Patent ID: 12215454

DETAILED DESCRIPTION

In the following description, like reference numerals refer to like elements throughout the specification. Well-known functions or constructions are not described in detail since they would obscure the one or more exemplar embodiments with unnecessary detail. Terms such as “unit”, “module”, “member”, and “block” may be embodied as hardware or software. According to embodiments, a plurality of “unit”, “module”, “member”, and “block” may be implemented as a single component or a single “unit”, “module”, “member”, and “block” may include a plurality of components.

It will be understood that when an element is referred to as being “connected” another element, it can be directly or indirectly connected to the other element, wherein the indirect connection includes “connection via a wireless communication network”.

Also, when a part “includes” or “comprises” an element, unless there is a particular description contrary thereto, the part may further include other elements, not excluding the other elements.

Throughout the description, when a member is “on” another member, this includes not only when the member is in contact with the other member, but also when there is another member between the two members.

It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, but is should not be limited by these terms. These terms are only used to distinguish one element from another element.

As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

An identification code is used for the convenience of the description but is not intended to illustrate the order of each step. The each step may be implemented in the order different from the illustrated order unless the context clearly indicates otherwise.

Reference will now be made in detail to embodiments of the disclosure, examples of which are illustrated in the accompanying drawings.

FIG.1schematically illustrates a washer according to an embodiment of the disclosure.

Referring toFIG.1, a washer100may include a drum130, a processor190, a motor drive200, a motor140, and a sensor180.

The drum130may accommodate laundry for washing. The drum130may be rotated by the motor140.

During the drum130is rotated, the laundry accommodated in the drum130may be washed. For example, during the drum130is rotated, the laundry may fall from top to bottom, and the laundry may be washed by mechanical impact (or friction) caused by the fall. As another example, during the drum130is rotated, the laundry may collide with water accommodated in the drum130, and the laundry may be washed by mechanical impact (or friction) caused by the collision.

In addition, water may be separated from the laundry by the rotation of the drum130. In other words, the laundry may be spin-dried by the rotation of the drum130. For example, during the drum130is rotated, water may be separated from the laundry by the centrifugal force, and the separated water may be discharged to an outside of the washer100.

The processor190may provide an electrical signal (hereinafter, referred to as a “target speed command”) corresponding to a target speed for rotating the drum130, to a motor drive200. For example, the processor190may store a rotational speed (angular velocity) of the drum130for washing, a rotational speed of the drum130for rinsing, and a rotational speed of the drum130for spin-drying. The processor190may provide the motor drive200with a target speed corresponding to a progress of a washing operation (washing, rinsing, or spin-drying).

In addition, the processor190may provide the motor drive200with a target speed command for measuring a weight (i.e., load) of the laundry accommodated in the drum130.

The target speed for measuring the load may vary over time. For example, as illustrated inFIG.1, the target speed may be provided as a sum of a first target speed having a predetermined magnitude that does not change over time and a second target speed in the form of a sinusoidal wave that changes over time. In other words, the target speed for measuring the load may be in the form of a sinusoidal wave in which a magnitude of a rotational speed changes over time without a change in a rotation direction.

As mentioned above, the processor190may provide a target speed command, which has a waveform in which a sinusoidal wave is superimposed on a constant value, to the motor drive200.

The motor drive200may receive the target speed command from the processor190, and may provide a driving current corresponding to the target speed command to the motor140.

The motor drive200may control the driving current, which is provided to the motor140, based on a difference between the target speed and the measured speed of the motor140. For example, the motor drive200may receive information about the rotation of the motor140from the sensor180. The motor drive200may receive rotational displacement of a rotating shaft of the motor140from the sensor180, and may determine a rotational speed of the rotating shaft based on the received rotational displacement. In this case, the motor drive200may provide information about a rotational speed of the rotating shaft to the processor190.

The motor drive200may increase the driving current in response to the measured speed of the motor140being less than the target speed. Further, the motor drive200may reduce the driving current in response to the measured speed of the motor140being greater than the target speed.

The motor drive200may receive the target speed command for measuring a load from the processor190.

The motor drive200may provide a driving current including a sinusoidal current to the motor140in response to a target speed command having a waveform in which a sinusoidal wave is superimposed on a predetermined value. Particularly, the motor drive200receiving the target speed command that changes over time may provide a driving current, which changes over time, to the motor140so as to allow the rotational speed of the motor140to follow the target speed command. Further, the motor drive200may provide an electrical signal representing a value of the driving current to the processor190.

The motor140may receive the driving current from the motor drive200and rotate the drum130and the laundry (load) accommodated in the drum130in response to the driving current supplied from the motor drive200.

For example, the motor140may include a permanent magnet that forms a magnetic field and a coil that forms a magnetic field in response to a driving current. The motor140may rotate the rotating shaft connected to the drum130using the magnetic field of the permanent magnet and a magnetic interaction between coils. In other words, the magnetic field of the permanent magnet and the magnetic interaction between the coils may provide a torque to the rotating shaft, and in response to the torque, the rotating shaft may be rotated.

In this case, the motor140may receive the driving current having the waveform, in which the sinusoidal wave is superimposed on the constant value, from the motor drive200. In other words, the motor140may receive the driving current having the magnitude that changes over time from the motor drive200.

Accordingly, a torque that changes over time may be applied to the rotating shaft of the motor140. Due to the time-varying torque, the rotational speed of the rotating shaft and the drum130may change over time as illustrated inFIG.1. In addition, due to the time-varying torque, the change in the rotational speed, that is, the rotational acceleration (angular acceleration) may also change over time.

In this case, the magnitude of the change in the rotational acceleration may be changed according to the weight of the laundry accommodated in the drum130, that is the load, according to the laws of physics (Newton's first law of motion). For example, as the load increases, the magnitude of the change in the rotational acceleration may decrease, and as the load decreases, the magnitude of the change in the acceleration may increase.

The sensor180may detect the rotation of the rotating shaft of the motor140(e.g., rotational displacement, rotational speed, rotation direction, etc.), and transmit an electrical signal corresponding to the detected rotation of the rotating shaft to the processor190and the motor drive200. For example, the sensor180may detect the rotational displacement and the rotation direction of the rotating shaft, and may provide the rotational displacement and rotation direction to the processor190.

The processor190may receive a driving current value and a rotational speed value of the rotating shaft from the motor drive200. The processor190may determine the rotational acceleration (angular acceleration of the rotating shaft) of the rotating shaft based on the rotational speed of the rotating shaft.

The driving current may be a waveform in which a sinusoidal wave is superimposed on a constant value. Further, the rotational speed may be in the form of a sinusoidal wave without a change in the rotation direction, and thus the rotational acceleration of the rotating shaft may be in the form of a sinusoidal wave.

The processor190may determine the magnitude of the load accommodated in the drum130based on the driving current value, in which the sinusoidal wave is superimposed, supplied to the motor140, and the rotational acceleration of the rotating shaft in the form of a sinusoidal wave. For example, the processor190may determine the magnitude of the load accommodated in the drum130based on a ratio between an amplitude of the driving current and an amplitude of the rotational acceleration.

As described above, the processor190may control the motor drive200to supply a driving current including a sinusoidal wave to the motor140, and the processor190may identify the rotational acceleration of the motor140by the driving current including the sinusoidal wave. The processor190may identify the magnitude of the load of the drum130connected to the rotating shaft of the motor140based on the driving current supplied to the motor140and the rotational acceleration of the motor140.

Hereinafter a configuration and operation of the washer100will be described.

FIG.2illustrates a configuration of the washer according to an embodiment of the disclosure.FIG.3illustrates an example of the washer according to an embodiment of the disclosure.FIG.4illustrates another example of the washer according to an embodiment of the disclosure.FIG.5illustrates an example of a motor drive included in the washer according to an embodiment of the disclosure.FIG.6illustrates another example of the motor drive included in the washer according to an embodiment of the disclosure.

Referring toFIGS.2,3,4,5and6, the washer100may include a control panel110, a tub120, the drum130, the motor140, a water supplier150, a detergent supplier155, a drain160, the motor drive200, a water level sensor170, and the processor190.

The washer100may include a cabinet101accommodating components included in the washer100. The control panel110, the water level sensor170, the motor drive200, the motor140, the water supplier150, the drain160, the detergent supplier155, the drum130and the tub120may be accommodated in the cabinet101.

An inlet101afor inserting or withdrawing laundry is provided on one surface of the cabinet101.

For example, the washer100may include a top-loading washer in which an inlet101afor inserting or withdrawing laundry is arranged on an upper surface of the cabinet101as illustrated inFIG.3or a front-loading washer in which an inlet101afor inserting or withdrawing is arranged on a front surface of the cabinet101as illustrated inFIG.4. In other words, the washer100according to an embodiment is not limited to the top-loading washer or the front-loading washer, and either the top-loading washer or the front-loading washer may be used. Alternatively, the washer100may include a washer of another loading type other than the top-loading washer and the front-loading washer.

A door102configured to open and close the inlet101ais arranged on one surface of the cabinet101. The door102may be arranged on the same surface as the inlet101a, and may be rotatably mounted to the cabinet101by a hinge.

The control panel110configured to provide a user interface for interaction with a user may be arranged on one surface of the cabinet101.

The control panel110may include an input button111configured to obtain a user input, and a display112provided to display laundry setting or laundry operation information in response to the user input.

The input button111may include a power button, an operation button, a course selection dial (or a course selection button), and a washing/rinsing/drying set button. The input button may include a tact switch, a push switch, a slide switch, a toggle switch, a micro switch, ora touch switch.

The input button111may provide an electrical output signal corresponding to a user input to the processor190.

The display112may include a screen provided to display a washing course selected by rotation of the course selection dial (or pressing a course selection button) and an operating time of the washer, and an indicator provided to display a washing setting/rinsing setting/spin-drying setting selected by the setting button. The display may include a liquid crystal display (LCD) panel, a light emitting diode (LED) panel, and the like.

The display112may receive information to be displayed from the processor190and display information corresponding to the received information.

The tub120may be arranged inside the cabinet101. The tub120may accommodate water for washing or rinsing.

The tub120may be formed in a cylindrical shape with one bottom open. The tub120may include a substantially circular tub bottom122and a tub sidewall121provided along a circumference of the tub bottom122. Another bottom surface of the tub120may be opened or an opening may be formed thereon to allow the laundry to be inserted or withdrawn.

In the case of the top-loading washer, as illustrated inFIG.3, the tub120may be arranged such that the tub bottom122faces a floor of the washer and a central axis R of the tub sidewall121is approximately perpendicular to the floor. In addition, in the case of the front-loading washer, as illustrated inFIG.4, the tub120may be arranged such that the tub bottom122faces the rear of the washer and a central axis R of the tub sidewall121is approximately parallel to the floor.

A bearing122aprovided to rotatably fix the motor140may be provided on the tub bottom122.

The drum130may be rotatably provided inside the tub120. The drum130may accommodate laundry, that is, a load.

The drum130may be formed in a cylindrical shape with one bottom open.

The drum130may include a substantially circular drum bottom132and a drum sidewall131provided along a circumference of the drum bottom132. Another bottom surface of the drum130may be opened or an opening may be formed thereon to allow the laundry to be inserted into or withdrawn from the drum130.

In the case of the top-loading washer, as illustrated inFIG.3, the drum130may be arranged such that the drum bottom132faces the floor of the washer and the central axis R of the drum sidewall131is approximately perpendicular to the floor. In addition, in the case of the front-loading washer, as illustrated inFIG.4, the drum130may be arranged such that the drum bottom132faces the rear of the washer and the central axis R of the drum side wall131is approximately parallel to the floor.

A through hole131aprovided to connect an inside and the outside of the drum130may be provided in the drum sidewall131to allow the water supplied to the tub120to be introduced into the inside of the drum130.

In the case of the top-loading washer, as illustrated inFIG.3, a pulsator133may be rotatably provided inside the drum bottom132. The pulsator133may be rotated independently of the drum130. In other words, the pulsator133may be rotated in the same direction as the drum130or rotated in a different direction. The pulsator133may be also rotated at the same rotational speed as the drum130or rotated at a different rotational speed.

In the case of the front-loading washer, as illustrated inFIG.4, a lifter131bis provided on the drum sidewall131to lift the laundry to an upper portion of the drum130during the drum130is rotated.

The drum bottom132may be connected to a rotating shaft141of the motor140configured to rotate the drum130.

The motor140may generate a torque for rotating the drum130.

The motor140may be provided outside the tub bottom122of the tub120, and may be connected to the drum bottom132of the drum130through the rotating shaft141. The rotating shaft141may penetrate the tub bottom122and may be rotatably supported by the bearing122aprovided on the tub bottom122.

The motor140may include a stator142fixed to the outside of the tub bottom122, and a rotor143configured to be rotatable with respect to the tub120and the stator142. The rotor143may be connected to the rotating shaft141.

The rotor143may be rotated through the magnetic interaction with the stator142, and the rotation of the rotor143may be transmitted to the drum130through the rotating shaft141.

The motor140may include a brushless direct current motor (BLDC Motor) or a permanent magnet synchronous motor (PMSM), which facilitates control of the rotational speed.

In the case of the top-loading washer, as illustrated inFIG.3, a clutch145configured to transmit the torque of the motor140to both of the pulsator133and the drum130, or to transmit the torque of the motor140to only the pulsator133may be provided. The clutch145may be connected to the rotating shaft141. The clutch145may distribute the rotation of the rotating shaft141to an inner shaft145aand an outer shaft145b. The inner shaft145amay be connected to the pulsator133. The outer shaft145amay be connected to the drum bottom132. The clutch145may transmit the rotation of the rotating shaft141to both of the pulsator133and the drum130through the inner shaft145aand the outer shaft145bor transmit the rotation of the rotating shaft141to only the drum130through the inner shaft145a.

The water supplier150may supply water to the tub120and the drum130. The water supplier150includes a water supply conduit151connected to an external water supply source to supply water to the tub120, and a water supply valve152arranged on the water supply conduit151. The water supply conduit151may be arranged on an upper side of the tub120and extend from the external water supply source to a detergent box156. Water is guided to the tub120through the detergent box156. The water supply valve152may allow or block supply of water from the external water supply source to the tub120in response to an electrical signal. The water supply valve152may include a solenoid valve configured to open and close in response to an electrical signal.

The detergent supplier155may supply detergent to the tub120and the drum130. The detergent supplier155includes the detergent box156arranged on the upper side of the tub120to store detergent, and a mixing conduit157provided to connect the detergent box156to the tub120. The detergent box156may be connected to the water supply conduit151, and water supplied through the water supply conduit151may be mixed with the detergent of the detergent box156. A mixture of detergent and water may be supplied to the tub120through the mixing conduit157.

The drain160may discharge the water accommodated in the tub120or the drum130to the outside. The drain160may include a drainage conduit161provided under the tub120and extend from the tub120to the outside of the cabinet101. In the case of the top-loading washer, as illustrated inFIG.3, the drain160may further include a drain valve162provided in the drain conduit161. In the case of the front-loading washer, as illustrated inFIG.4, the drain160may further include a drain pump163arranged on the drain conduit161.

The water level sensor170may be installed at an end of a connection hose connected to a lower portion of the tub120. In this case, a water level of the connection hose may be the same as a water level of the tub120. As the water level of the tub120is increased, the water level of the connection hose may be increased, and a pressure inside the connection hose may be increased due to the increase of the water level of the connection hose.

The water level sensor170may measure the pressure inside the connection hose, and may output an electrical signal corresponding to the measured pressure to the processor190. The processor190may identify the water level of the connection hose, that is, the water level of the tub110, based on the pressure of the connection hose measured by the water level sensor170.

The motor drive200may receive a driving signal from the processor190, and provide a driving current for rotating the rotating shaft141of the motor140to the motor140based on the driving signal of the processor190. The motor drive200may provide the driving current value supplied to the motor140and the rotational speed of the rotor of the motor140to the processor190.

As illustrated inFIGS.5and6, the motor drive200may include a rectifier circuit210, a direct current (DC) link circuit220, an inverter circuit230, a current sensor240or a drive processor250. Further, the motor140may be provided with a position sensor270configured to measure the rotational displacement (electrical angle of the rotor) of the rotor143.

The rectifier circuit210may include a diode bridge including a plurality of diodes D1, D2, D3, and D4, and may rectify AC power of the external power source (ES).

The DC link circuit220may include a DC link capacitor C1configured to store electrical energy, and the DC link circuit220may remove a ripple of the rectified power, and output DC power.

The inverter circuit230may include three pairs of switching elements Q1and Q2, Q3and Q4, Q5and Q6, and convert the DC power of the DC link circuit220into DC or AC driving power. The inverter circuit230may also supply a driving current to the motor140.

The current sensor240may measure a total current output from the inverter circuit230or measure each of the three-phase driving currents (a-phase current, b-phase current, and c-phase current) output from the inverter circuit230.

The position sensor270may be arranged in the motor140, and measure the rotational displacement (e.g., the electric angle of the rotor) of the rotor143of the motor140, and output positional data θ indicating the electric angle of the rotor143. The position sensor270may be implemented as a Hall sensor, an encoder, a resolver, or the like.

The drive processor250may be provided integrally with the processor190or provided separately from the processor190.

The drive processor250may include an application specific integrated circuit, (ASIC) configured to output a driving signal to the inverter circuit230based on the target speed command ω*, the driving current value, and the rotational displacement θ of the rotor143. Alternatively, the drive processor250may include a memory configured to store a series of instructions for outputting a driving signal based on the target speed command ω*, the driving current value, and the rotational displacement θ of the rotor143, and a processor configured to process the series of instructions stored in the memory.

A structure of the drive processor250may depend on the type of the motor140. In other words, the drive processors250including different structures may control different types of motors140.

For example, when the motor140is a BLDC motor, the drive processor250may include a speed calculator251, a speed controller253, a current controller254, and a pulse width modulator256, as illustrated inFIG.5.

The drive processor250may control a DC voltage applied to the BLDC motor by using pulse width modulation (PWM). Accordingly, the driving current supplied to the BLDC motor may be controlled.

The speed calculator251may calculate a rotational speed value w of the motor140based on a rotor electric angle θ of the motor140. For example, the speed calculator251may calculate the rotational speed value w of the motor140based on a magnitude of change in the electric angle θ of the rotor143received from the position sensor270. As another example, the speed calculator251may calculate the rotational speed value w of the motor140based on a change in the driving current value measured by the current sensor240.

The speed controller253may output a current command I* based on a difference between the target speed command ω* of the processor190and the rotational speed value ω of the motor140. For example, the speed controller253may include a proportional integral controller (PI controller).

The current controller254may output a voltage command V* based on the difference between the current command I* output from the speed controller253and the measured current value I measured by the current sensor240. For example, the current controller254may include a PI controller.

The pulse width modulator256may output a PWM control signal Vpwm for controlling the magnitude of the driving current that is supplied by the inverter circuit230to the motor140based on the voltage command V*.

As mentioned above, the drive processor250may control the magnitude of the driving current supplied by the inverter circuit230to the motor140based on the target speed command ω* received from the processor190.

The drive processor250may supply a driving current including a sinusoidal waveform to the motor140, in response to the target speed command ω* including the sinusoidal waveform. For example, the speed controller253may output the current command I* including the sinusoidal waveform, in response to the target speed command ω* including the sinusoidal waveform. Further, the current controller254may output a voltage command V* including a sinusoidal waveform, in response to the current command I* including the sinusoidal waveform.

Further, the drive processor250may supply a driving current including a sinusoidal waveform to the motor140, in response to a load measurement command of the processor190. For example, the speed controller253may output a current command I* including a sinusoidal waveform, in response to the load measurement command of the processor190. The speed controller253may output the current command I* in which a current command of a sinusoidal waveform is superimposed on a current command based on a difference between the target speed command ω* and the rotational speed value w. Further, the current controller254may output a voltage command V* including a sinusoidal waveform, in response to the load measurement command of the processor190. The current controller254may output the voltage command V* in which a voltage command of a sinusoidal waveform is superimposed on a voltage command based on a difference between the current command I* and the measured current I.

As another example, when the motor140is a PMSM, the drive processor250may include a speed calculator251, an input coordinate converter252, a speed controller253, a current controller254, an output coordinate converter255, and a pulse width modulator256, as illustrated inFIG.6.

The drive processor250may control the AC voltage applied to the PMSM using vector control. Accordingly, the driving current supplied to the PMSM may be controlled.

The speed calculator251may be the same as the speed calculator251illustrated inFIG.5.

The input coordinate converter252may convert a three-phase driving current value labc to a d-axis current value Id and a q-axis current value Iq (hereinafter, d-axis current and q-axis current) based on a rotor electrical angle θ. The d-axis may represent an axis in a direction coincident with the direction of the magnetic field generated by the rotor of the motor140. In addition, the q-axis may represent an axis in a direction 90 degrees ahead of the direction of the magnetic field generated by the rotor of the motor140.

The speed controller253may calculate a q-axis current command Iq* to be supplied to the motor140based on a difference between the target speed command ω* of the processor190and the rotational speed value w of the motor140. Further, the speed controller253may determine the d-axis current command Id*.

The current controller254may determine a q-axis voltage command Vq* based on a difference between the q-axis current command Iq* output from the speed controller253and the q-axis current value Iq output from the input coordinate converter252. Further, the current controller254may determine a d-axis voltage command Vd* based on a difference between the d-axis current command Id* and the d-axis current value Id.

The output coordinate converter255may convert a dq-axis voltage command Vdq* to a three-phase voltage command Vabc* (a-phase voltage command, b-phase voltage command, and c-phase voltage command) based on the rotor electrical angle θ of the motor140.

The pulse width modulator256may output a PWM control signal Vpwm for controlling the magnitude of the driving current that is supplied to the motor140by the inverter circuit230from the three-phase voltage command Vabc*.

As mentioned above, the drive processor250may control the magnitude of the driving current supplied by the inverter circuit230to the motor140based on the target speed command ω* received from the processor190.

The drive processor250may supply a driving current including a sinusoidal waveform to the motor140, in response to the target speed command ω* including the sinusoidal waveform. For example, the speed controller253may output a q-axis current command Iq* including a sinusoidal waveform, in response to the target speed command ω* including the sinusoidal waveform. Further, the current controller254may output a q-axis voltage command Vq* including a sinusoidal waveform, in response to the q-axis current command Iq* including the sinusoidal waveform.

Further, the drive processor250may supply a driving current including a sinusoidal waveform to the motor140, in response to the load measurement command of the processor190. For example, the speed controller253may output a q-axis current command Iq* with a sinusoidal waveform in response to a load measurement command from the processor190. The speed controller253may output a q-axis current command Iq*, in which a current command of a sinusoidal waveform is superimposed on a current command based on a difference between the target speed command ω* and the rotational speed value w. Further, the current controller254may output a q-axis voltage command Vq* including a sinusoidal waveform in response to a load measurement command of the processor190. For example, the current controller254may output a q-axis voltage command Vq* in which a voltage command of a sinusoidal waveform is superimposed on a voltage command based on the difference between the q-axis current command Iq* and the measured q-axis current Iq.

The processor190may be mounted on a printed circuit board provided on a rear surface of the control panel110.

The processor190may be electrically connected to the control panel110, the water level sensor170, the motor drive200, the water supply valve152, or the drain valve162/drain pump163.

The processor190may process an output signal of the control panel110, the water level sensor170, or the motor drive200, and the processor190may provide a control signal to the motor drive200, the water supply valve152, and the drain valve162/the drain pump163based on processing the output signal.

The processor190may include a memory191configured to store or memorize a program (a plurality of instructions) or data for processing a signal and providing a control signal. The memory191may include a volatile memory such as Static Random Access Memory (S-RAM) and Dynamic Random Access Memory (D-RAM), and a non-volatile memory such as Read Only Memory (ROM), and Erasable Programmable Read Only Memory (EPROM). The memory191may be provided integrally with the processor190as illustrated inFIG.2or may be provided as a semiconductor device separated from the processor190.

The processor190may further include a processing core (e.g., an arithmetic circuit, a memory circuit, and a control circuit) configured to process a signal based on a program or data stored in the memory191and configured to output a control signal.

The processor190may receive a user input from the control panel110and process the user input. The processor190may provide a control signal to the motor drive200, the water supply valve152, and the drain valve162/the drain pump163to sequentially perform the washing cycle, the rinsing cycle, and the spin-drying cycle in response to a user input signal.

The processor190may receive a water level measured by the water level sensor170. The processor190may provide a water supply signal to the water supply valve152or a drain signal to the drain valve162/the drain pump163based on the comparison between the measured water level and the target water level.

The processor190may provide a driving signal to the motor drive200to allow the motor140to rotate the drum130. For example, the processor190may provide a driving signal for the washing to the motor drive200. In addition, the processor190may provide a driving signal for the spin-drying to the motor drive200.

The processor190may provide a driving signal for measuring a load to the motor drive200.

For example, the processor190may provide a target speed command, in which a sinusoidal waveform is superimposed, for measuring a load to the motor drive200. The motor drive200may supply a driving current including the sinusoidal current to the motor140in response to the target speed command on which the sinusoidal waveform is superimposed.

As another example, the processor190may provide a load measurement signal for measuring a target rotational speed and a load to the motor drive200. The motor drive200may supply a driving current including a sinusoidal waveform to the motor140in response to the load measurement signal.

The processor190may receive a driving current value and a rotational speed of the motor140supplied to the motor140from the motor drive200. The processor190may measure the weight of the laundry accommodated in the drum130, i.e., a load, based on the driving current value of the motor140and the rotational speed of the motor140.

For example, the processor190may identify an amplitude of the change in the driving current based on the value of the driving current of the motor140, and identify an amplitude of the change in the rotational acceleration based on the rotational speed of the motor140. The processor190may identify a moment of inertia by the drum130and the load, based on a ratio between the amplitude of the change in driving current and the amplitude of the change in rotational acceleration. The processor190may identify the magnitude of the load accommodated in the drum130based on the moment of inertia caused by the drum130and the load.

Further, based on the identified load, the processor190may set the water level of the tub120or identify whether a waterproof fabric (e.g., waterproof clothing or waterproof bedding) is included in the laundry, or identify a moisture content of laundry during the spin-drying.

FIG.7illustrates a method of measuring a load of the washer according to an embodiment of the disclosure.FIG.8illustrates a rotational speed of the motor, a driving current of the motor, a rotational acceleration of the motor, and a load of the motor measured by the method illustrated inFIG.7.FIG.9illustrates the driving current of the motor on which a sinusoidal waveform is superimposed by the method illustrated inFIG.7.FIG.10illustrates a spectrum of the driving current of the motor illustrated inFIG.9.FIG.11illustrates a rotational acceleration of the motor on which the sinusoidal waveform is superimposed by the method illustrated inFIG.7.FIG.12illustrates a spectrum of the rotational acceleration of the motor illustrated inFIG.11.

A method1000in which the washer100measures the load accommodated in the drum130is described with reference toFIGS.7,8,9,10,11and12.

The rotation of the drum130is governed by [Equation 1] representing the following rotor dynamics equation.
τ=Ja+bω+c.[Equation 1]

Where T represents the torque applied to the rotating body (drum), J represents the moment of inertia of the rotating body (drum), a represents the rotational acceleration, ω represents the rotational speed, b represents the viscous friction coefficient, and c represents Coulomb friction.

The right side of [Equation 1] may be divided into “Ja” and “bω+c” by the rotational moment and rotational acceleration. At this time, when the change in the rotational speed is small, the rotational speed w and the viscous friction coefficient b are small values, and thus “bω+c” may be treated as a constant.

According to [Equation 1], the torque applied to the drum130may be proportional to the rotational acceleration of the drum130, and the ratio of the torque applied to the drum130to the rotational acceleration of the drum130may be equal to the moment of inertia of the drum130. In addition, the torque applied to the drum130by the motor140may be proportional to the magnitude of the driving current supplied to the motor140.

Accordingly, the washer100may identify the moment of inertia of the drum130based on the driving current supplied to the motor140and the rotational acceleration of the drum130. In other words, the washer100may identify the magnitude of the load accommodated in the drum130based on the driving current supplied to the motor140and the rotational acceleration of the drum130.

The washer100may rotate the motor140at a target speed (1010).

The processor190may provide a target speed command to the motor drive200to rotate the motor140at the target speed.

For example, before starting the washing of the washer100, the processor190may rotate the motor140at a first speed to measure a dry load (a weight of laundry that does not absorb water for washing) accommodated in the drum130.

As another example, before starting the spin-drying in the washer100, the processor190may rotate the motor140at a second speed to measure a wet load (a weight of laundry that absorbs water for washing) accommodated in the drum130.

As another example, during the spin-drying in the washer100, the processor190may rotate the motor140at a third speed to measure the wet load accommodated in the drum130.

The processor190may increase the rotational speed of the motor140stepwise or linearly or gradually until the rotational speed of the motor140reaches the target speed. In other words, the processor190may provide the motor drive200with a target speed command for the stepwise or linear or gradual increase, to allow the motor140to be accelerated.

Accordingly, the rotational speed of the motor140may be increased stepwise or linearly or gradually between time T1and time T2as illustrated inFIG.8.

The washer100identifies whether a time, for which the motor140is rotated at the target speed, is equal to or greater than a reference time (1020). In response to the time, for which the motor140is rotated at the target speed, being less than the reference time (no in1020), the washer100may wait until the rotational speed of the motor140is stabilized.

The processor190may wait for a reference time after the motor140reaches the target speed. The reference time is a time required for the rotational speed of the motor140to be stabilized, and may be set experimentally or empirically.

For example, in a state in which the load is small, an overshoot in which the rotational speed of the motor140exceeds the target speed may occur at a point of time in which the rotational speed of the motor140reaches the target speed. Due to the overshoot, the rotation (rotational speed and rotation acceleration) of the motor140may change due to external factors other than the driving current supplied to the motor140. In order to exclude the rotation of the motor140caused by the external factors, the processor190may wait for the rotational speed of the motor140to be stabilized.

Accordingly, the rotational speed of the motor140may be stabilized between time T2and time T3, as illustrated inFIG.8.

In response to the time, for which the motor140is rotated at the target speed, being equal to or greater than the reference time (yes in1020), the washer100may add a sinusoidal current to the driving current supplied to the motor140(1030).

The processor190may control the motor drive200to allow a sinusoidal waveform to be superimposed on the driving current supplied to the motor140.

For example, the processor190may add a sinusoidal waveform to the target speed command supplied to the motor drive200. The processor190may provide the target speed command that changes over time with a sinusoidal waveform, to the motor drive200.

In order to minimize the change in the rotational speed of the motor140during the load measurement, an amplitude of the added sinusoidal waveform may be minimized. For example, the amplitude of the added sinusoidal waveform may be a predetermined value (e.g., 5 RPM or less). Further, the amplitude of the added sinusoidal waveform may depend on the target speed. The amplitude of the added sinusoidal waveform may be 5% or less of the target speed (e.g., 5 RPM or less in response to the target speed of 100 RPM). Alternatively, the amplitude of the added sinusoidal waveform may be 0.5% or less of the maximum rotational speed for the spin-drying (e.g., 5 RPM or less in response to the target speed of 1000 RPM).

However, the disclosure is not limited thereto, and the amplitude of the sinusoidal waveform may be 2% or less of the target speed (e.g., 2 RPM or less in response to the target speed of 100 RPM). Alternatively, the amplitude of the added sinusoidal waveform may be 0.2% or less of the maximum rotational speed for the spin-drying (e.g., 2 RPM or less in response to the target speed of 1000 RPM).

An influence may occur by the movement of the laundry accommodated in the drum130during the load measurement. For example, in the case of the front-loading washer, laundry accommodated in the drum130may fall during the drum130is rotated at a low speed, thereby changing the rotational acceleration. In order to minimize the influence of the movement of laundry accommodated in the drum130during the load measurement, a frequency of the added sinusoidal waveform may be different from a frequency corresponding to the target speed. For example, the frequency of the added sinusoidal waveform may be less than the frequency corresponding to the target speed.

The motor drive200may provide a driving current on which the sinusoidal waveform is superimposed to the motor140in response to the target speed command on which the sinusoidal waveform is superimposed. Further, the motor drive200may provide the value of the driving current, on which the sinusoidal waveform is superimposed, to the processor190.

As another example, the processor190may provide the motor drive200with a load measurement command for adding a sinusoidal current to the driving current together with the target speed command. In response to the load measurement command, the motor drive200may provide the motor140with a driving current in which the sinusoidal current is added to a current based on the target speed command.

In order to minimize the change in the rotational speed of the motor140during the load measurement, the amplitude of the added sinusoidal current may be minimized. For example, the amplitude of the sinusoidal current may be limited within a predetermined range. Further, the amplitude of the sinusoidal current may depend on the target speed.

In addition, in order to minimize the influence of the movement of laundry accommodated in the drum130during the load measurement, the frequency of the added sinusoidal current may be different from the frequency corresponding to the target speed. For example, the frequency of the added sinusoidal current may be less than a frequency corresponding to the target speed.

Further, the motor drive200may provide the value of the driving current, to which the sinusoidal current is added, to the processor190.

The washer100may identify the rotational angular velocity of the motor140by the driving current including the sinusoidal waveform (1040).

The motor drive200may identify a rotational displacement of the rotor143of the motor140. For example, the motor drive200may identify the rotational displacement (electric angle) of the rotor143based on the output signal of the position sensor270provided in the motor140. As another example, the motor drive200may identify the rotational displacement (electric angle) of the rotor143based on a change in the current caused by the counter electromotive force of the motor140.

The motor drive200may identify the rotational speed (angular velocity) of the rotor143. For example, the motor drive200may identify the rotational speed of the rotor143based on a change in the rotational displacement of the rotor143per unit time.

The motor drive200may provide information about the rotational speed of the rotor143to the processor190.

The motor drive200may provide the rotational speed value of the rotor143to the processor190for each sampling period. As illustrated inFIG.8, the motor drive200may provide the rotational speed value of the rotor143to the processor190at times T4, T5, T6, T7. . . .

The processor190may identify the rotational acceleration (angular acceleration) of the rotor143. For example, for each sampling period, the processor190may identify the rotational acceleration of the rotor143based on a change in the rotational speed of the rotor143. As illustrated inFIG.8, the processor190may identify a rotational acceleration value of the rotor143at time T4, T5, T6, T7. . . .

In addition, the motor drive200may identify the rotational acceleration of the rotor143based on the change in the rotational speed of the rotor143per unit time, and transmit information about the rotational acceleration of the rotor143to the processor190.

The washer100may identify the magnitude of the load based on the driving current and the rotational acceleration (1050).

The processor190may identify the magnitude of the load accommodated in the drum130based on the driving current value and the rotational acceleration value obtained for each sampling period.

In order to remove a direct current (DC) component and a noise component included in the driving current value, the processor190may filter the driving current value (the sampled driving current value) obtained from the motor drive200for each sampling period.

As illustrated inFIG.9, the driving current may include a first driving current for rotating the drum130at a target speed, a second driving current by a sinusoidal component included in the target speed, and a third driving current for compensating for the movement of laundry in the drum130.

A frequency spectrum of the driving current may include a DC component for rotating the drum130at a target speed, a frequency component by the target speed of the sinusoidal wave, and a frequency component corresponding to the rotational speed (target speed) of the drum130. The frequency component according to the target speed of the sinusoidal wave and the frequency component corresponding to the rotational speed (target speed) of the drum130may be as illustrated inFIG.10.

The processor190may filter the driving current to remove the DC component and the frequency component corresponding to the rotational speed (target speed) of the drum130.

For example, the processor190may filter the driving current value by using a band pass filter (BPF) having the frequency of the sinusoidal wave added to the target speed (or the frequency of the sinusoidal current added to the driving current), as a center frequency. Accordingly, the DC component and the frequency component corresponding to the rotational speed of the drum130included in the driving current value may be removed.

However, filtering the sampled driving current value is not limited to filtering the driving current value using a band pass filter. For example, the filtering of the sampled driving current value may include filtering the driving current value using a low pass filter (LPF) for removing the DC component. In addition, the filtering of the sampled driving current value may include filtering the driving current value using a high pass filter (HPF) for removing the frequency component corresponding to the rotational speed of the drum130.

In order to remove a noise component included in the rotational acceleration value, the processor190may filter the rotational acceleration value (sampled rotational acceleration value) obtained from the motor drive200for each sampling period.

As illustrated inFIG.11, the rotational acceleration may include a first rotational acceleration by a sinusoidal component included in the target speed, and a second rotational acceleration by the movement of laundry in the drum130.

As illustrated inFIG.12, a frequency spectrum of the rotational acceleration may include a frequency component by the target speed of the sinusoidal wave and a frequency component corresponding to the rotational speed (target speed) of the drum130.

The processor190may filter the rotational acceleration to remove a frequency component corresponding to the rotational speed (target speed) of the drum130.

For example, the processor190may filter the rotational acceleration value by using a band pass filter (BPF) having the frequency of the sinusoidal wave added to the target speed (or the frequency of the sinusoidal current added to the driving current), as a center frequency. Accordingly, the DC component and the frequency component corresponding to the rotational speed of the drum130included in the rotational acceleration value may be removed. Alternatively, the processor190may filter the rotational acceleration value using a low-pass filter or a high-pass filter.

The processor190may identify the amplitude of the sampled driving current value and the amplitude of the sampled rotational acceleration value using the driving current model and the rotational acceleration model.

The driving current generated by the target speed of the sinusoidal waveform may be modeled as a cosine function (or sine function) as illustrated in [Equation 2], and the rotational acceleration may be modeled as illustrated in [Equation 3].
i(t)=Icos(θ−α)=Icos α* cos θ+Isin α*sin θ  [Equation 2]

Where i(t) represents the modeled driving current, I represents the amplitude of the driving current, a represents the phase delay of the driving current, and θ represents the phase of the sinusoidal waveform added to the target speed.
a(t)=Acos(θ−β)=Acos β*cos θ+Asin β*sin θ.  [Equation 2]

Where a(t) represents the modeled rotational acceleration, A represents the amplitude of the rotational acceleration, and β represents the phase delay of the rotational acceleration.

θ represents the phase of the sinusoidal wave at the time of sampling of the driving current and rotational acceleration. Accordingly, the processor190may identify the value of cos θ and the value of sin θ. Further, because i(t) represents the modeled driving current value, the processor190may identify the value of i(t).

Therefore, [Equation 2] and [Equation 3] may be simplified as [Equation 4] and [Equation 5], respectively.
zi=Mxi+Nyi.  [Equation 4]

Where zi represents the i-th sampled driving current value, M represents the product of the amplitude of the driving current and cos α, xi represents the cosine function value of the phase of the sinusoidal waveform added to the target speed at the i-th sampling, N represents the product of the amplitude of the driving current and sin α, and yi represents the sine function value of the phase of the sinusoidal waveform added to the target speed at the i-th sampling.
zi′=M′xi′+N′yi′.  [Equation 2]

Where zi′ represents the i-th sampled rotational acceleration value, M′ represents the product of the amplitude of the rotational acceleration and cos α, and xi′ represents the cosine function value of the phase of the sinusoidal waveform added to the target speed at the i-th sampling, N′ represents the product of the amplitude of rotational acceleration and sin α, and yi′ represents the sine function value of the phase of the sinusoidal waveform added to the target speed at the i-th sampling.

The processor190may identify a driving current value zi obtained by sampling of the driving current value, a cosine function value xi of the phase of the sinusoidal waveform, and a sine function value yi of the phase of the sinusoidal waveform, respectively. For example, the processor190may generate (z1, x1, y1), (z2, x2, y2), (z3, x3, y3) . . . (zi, xi, yi) through the sampling of the driving current value.

For example, the processor190may identify values of M and N in [Equation 4] using the least squares method. The processor190may identify the values of M and N by applying the least squares method to [Equation 4] to which (z1, x1, y1), (z2, x2, y2), (z3, x3, y3) . . . (zi, xi, yi) is given.

As another example, the processor190may identify the values of M and N in [Equation 4] using the recursive least squares method.

For example, as illustrated inFIG.8, the processor190may initialize parameters for applying the regressive least squares method using the least squares method at times T4, T5, T6, and T7.

As illustrated inFIG.8, at time T8, the processor190may identify the values of M and N by using the regressive least squares method by applying parameters that are initialized at times T4, T5, T6, and T7.

Because M represents the product of the amplitude of the driving current and cos α and N represents the product of the amplitude of the driving current and sin α, the processor190may identify the amplitude I of the driving current using [Equation 6].
I=√{square root over (M2+N2)}.  [Equation 6]

Where I represents the amplitude of the driving current, M represents the product of the amplitude of the driving current and cos α, and N represents the product of the amplitude of the driving current and sin α.

In addition, the processor190may identify a rotational acceleration value zi′ obtained by sampling of the rotational acceleration value, a cosine function value xi′ of the phase of the sinusoidal waveform, and a sine function value yi′ of the phase of the sinusoidal waveform, respectively. For example, the processor190may obtain (z1′, x1′, y1′), (z2′, x2′, y2′), (z3′, x3′, y3′) . . . (zi′, xi′, yi′) through the sampling of the rotational acceleration value.

For example, the processor190may identify the values of M′ and N′ in [Equation 5] using the least squares method. The processor190may identify the values of M and N by applying the least squares method to [Equation 5] to which (z1′, y1), (z2′, x2′, y2′), (z3′, x3′, y3′) . . . (zi′, xi′, yi′) is given.

In addition, the processor190may identify the values of M′ and N′ in [Equation 5] using the regressive least squares method. Thereafter, the processor190may identify the amplitude A of the rotational acceleration using [Equation 7].
A=√{square root over (M′2+N′2)}.  [Equation 7]

Where A represents the amplitude of the rotational acceleration, M′ represents the product of the amplitude of the rotational acceleration and cos α, and N′ represents the product of the amplitude of the rotational acceleration and sin α.

As mentioned above, the processor190may identify the amplitude of the driving current and the amplitude of the rotational acceleration by using the least-squares method or the regressive least-squares method, based on the sampled driving current value and the sampled rotational acceleration value.

The processor190may identify the moment of inertia of the drum130and the laundry based on a ratio of the amplitude of the driving current to the amplitude of the rotational acceleration. For example, the processor190may identify the moment of inertia using [Equation 8].

J=Kt⁢IA.[Equation⁢8]

Where J represents the moment of inertia, Kt represents the motor torque constant, I represents the amplitude of the driving current, and A represents the amplitude of the rotational acceleration.

The processor190may identify the magnitude of the load (the weight of the laundry accommodated in the drum) based on the moment of inertia of the drum130and the laundry.

In addition, in response to a sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify the moment of inertia of the drum130and the laundry based on the amplitude of the rotational acceleration.

For example, because the motor torque constant Kt in [Equation 8] is a known constant, the calculated value of the right side of [Equation 8] may be proportional to the moment of inertia J.

Accordingly, the processor190may calculate the moment of inertia J from the amplitude A of the rotational acceleration. In addition, the processor190may store a lookup table including a plurality of calculated values of the right side of [Equation 8] and a plurality of moments of inertia J corresponding thereto, and using the lookup table, may identify the moment of inertia J from the amplitude I of the driving current and the amplitude A of the rotational acceleration.

As described above, the washer100may supply the driving current including the sinusoidal current to the motor140and identify the magnitude of the load based on the rotational acceleration of the rotor143.

The washer100may identify the magnitude of the load while minimizing the change in the rotational speed of the motor140. Accordingly, the washer100may identify the magnitude of the load not only in the low-speed section but also in the high-speed section.

FIG.13illustrates a method for the washer according to an embodiment of the disclosure to set a water level for washing and rinsing.

A method1100of setting a washing/rinsing water level of the washer100will be described with reference toFIG.13.

The washer100may rotate the motor140at the first speed (1110).

The processor190may provide a target speed command to the motor drive200to rotate the motor140at the first speed in response to a user input for starting the operation of the washer100. For example, the processor190may provide the motor drive200with the target speed command, which is to increase stepwise or linearly or gradually, to allow the motor140to be accelerated to the first speed. The first speed may be a rotational speed of the drum130for measuring the dry load (the weight of the laundry that does not absorb water for washing) accommodated in the drum130. For example, the first speed may be less than a rotational speed corresponding to the resonant frequency of the tub120in order to prevent or suppress vibration and noise of the tub120.

Resonance is a phenomenon in which the vibration of the tub120is greatly increased by the rotation of the drum130, and the vibration of the tub120may be amplified at a specific rotational speed of the drum130. The resonance may include a first resonance generated in a first resonance section and a second resonance generated in a second resonance section. In the first resonance, the entire tub120may vibrate left and right, and in the second resonance, the upper (front) and lower (rear) portions of the tub120may vibrate in opposite directions.

The washer100may add a sinusoidal current to the driving current supplied to the motor140(1120).

Operation1120may be the same as operation1030illustrated inFIG.7. For example, the processor190may control the motor drive200to allow a sinusoidal waveform to be superimposed on the driving current supplied to the motor140.

The washer100may identify the magnitude of the first load based on the driving current and the rotational acceleration (1130).

Operation1130may be the same as operation1040and operation1050illustrated inFIG.7. For example, the motor drive200may provide the driving current value and the rotational speed value of the rotor143to the processor190for each sampling period. The processor190may identify a rotational acceleration value of the rotor143based on a differential value of the value of the rotational speed of the rotor143. Further, the processor190may identify the magnitude of the dry load accommodated in the drum130based on the driving current value and the rotational acceleration value obtained for each sampling period.

Further, in response to the sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify the magnitude of the dry load accommodated in the drum130based on the rotational acceleration value obtained for each sampling period.

The washer100may set the water level of the tub120based on the magnitude of the first load (the weight of the dry load) (1140), and supply water to the tub120based on the set water level (1150).

The processor190may store a lookup table including the magnitude of the dry load and the water level of the tub120corresponding the magnitude of the dry load. The processor190may identify the set level of the tub120corresponding to the measured magnitude of the first load using the lookup table.

Further, the processor190may store a lookup table including the amplitude of the rotational acceleration of the motor140and the water level of the tub120corresponding the amplitude of the rotational acceleration. The processor190may identify the set level of the tub120corresponding to the measured amplitude of the rotational acceleration using the lookup table.

The processor190may control the water supplier150to supply water to the tub120. The processor190may identify the water level of the tub120based on the output of the water level sensor170during water is supplied to the tub120. The processor190may stop supplying water to the tub120in response to the water level of the tub120being greater than or equal to the set water level.

The washer100may perform washing or rinsing (1160).

After supplying water to the tub120up to the set water level, the processor190may control the motor drive200to perform the washing or rinsing. For example, the processor190may control the motor drive200to allow the motor140to rotate the drum130or the pulsator133at the rotational speed for the washing/rinsing.

As described above, the washer100may measure the dry load by supplying a sinusoidal current to the motor140before starting an operation for washing laundry.

Accordingly, the washer100may measure the dry load without the rotational speed of the drum130entering a resonance region of the tub120.

FIG.14illustrates a method of identifying whether a waterproof fabric is included in a load of the washer according to an embodiment of the disclosure.FIG.15illustrates a rotational speed, a rotational acceleration and a driving current by the method illustrated inFIG.14.

A method1200of identifying whether or not a waterproof fabric is included in the laundry contained in the drum130is described with reference toFIGS.14and15.

The washer100may rotate the motor140at a second speed (1210).

As described with reference toFIG.13, the processor190may supply water to the tub120to perform the washing or rinsing. The processor190may control the drain160to discharge the water contained in the tub120to the outside based on the completion of washing or rinsing.

The processor190may control the motor drive200to rotate the drum130at the second speed in response to the water level of the tub120being less than or equal to the reference water level (e.g., “0”) during drainage. For example, the processor190may provide the motor drive200with a target speed command, which is to increase stepwise or linearly or gradually, to allow the motor140to be accelerated to the second speed. The second speed may be a rotational speed of the drum130for measuring a wet load (weight of laundry absorbing water for washing) accommodated in the drum130. For example, in order to prevent or suppress the vibration and noise of the tub120, the second speed may be less than or greater than the rotational speed corresponding to the first resonance section of the tub120.

As illustrated inFIG.15, the processor190may control the motor drive200to allow the rotational speed of the motor140to reach the second speed V2between time T1and time T2. The motor drive200may provide the motor140with a first driving current I1for increasing the rotational speed of the motor140between time T1and time T2. In response to the first driving current I1, the rotational acceleration of the motor140may increase to a first acceleration A1between time T1and time T2.

The washer100may add a sinusoidal current to the driving current supplied to the motor140(1220).

Operation1220may be the same as operation1030illustrated inFIG.7. For example, the processor190may control the motor drive200to allow a sinusoidal waveform to be superimposed on the driving current supplied to the motor140.

As illustrated inFIG.15, the processor190may provide a target speed command including a sinusoidal waveform or a load measurement command for load measurement to the motor drive200between time T2and time T3. The motor drive200may supply the second driving current I2including a sinusoidal current to the motor140between time T2and time T3. In response to the second driving current I2, the rotational acceleration of the motor140may be a second acceleration A2in the form of a sinusoidal wave between time T2and time T3.

The washer100may identify the magnitude of the second load based on the driving current and the rotational acceleration (1230).

Operation1230may be the same as operation1040and operation1050illustrated inFIG.7. For example, the processor190may identify the magnitude of the second load (wet load) accommodated in the drum130based on the driving current value and the rotational acceleration value obtained for each sampling period.

In addition, in response to a sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify the magnitude of the second load (wet load) accommodated in the drum130based on the rotational acceleration value obtained for each sampling period.

The second load (wet load) may indicate the weight of the laundry absorbing water for washing or rinsing. Accordingly, the second load may be greater than the first load (dry load) indicating the weight of the laundry that does not absorb water.

The washer100may identify whether the waterproof fabric is included in the laundry based on the magnitude of the second load (1240).

The processor190may identify whether or not the waterproof fabric is included in the laundry based on the comparison between the dry load (first load) and the wet load (second load).

In response to the laundry not including the waterproof fabric, a ratio of the second load to the first load may be within a predetermined range. Conventional fabrics (including clothing and bedding) may not absorb water indefinitely, and absorb water according to a specific range of absorption rates. In other words, the ratio of the weight of the wet fabric to the weight of the dry fabric may be less than a predetermined value (e.g., a maximum absorption of the conventional fabric).

On the other hand, in response to the laundry including the waterproof fabric, the ratio of the second load to the first load may be out of a predetermined range. The waterproof fabric may trap water that is supplied during the washing or rinsing. Accordingly, the ratio of the weight of the water-entrained waterproof fabric to the weight of the dry waterproof fabric may be greater than a predetermined value (e.g., the maximum absorption of the conventional fabric).

Accordingly, the processor190may identify whether the waterproof fabric is included in the laundry based on a ratio of the magnitude of the second load to the magnitude of the first load.

For example, the processor190may identify whether or not the waterproof fabric is included in the laundry based on [Equation 9].
J2>R1J1+J0[Equation 9]

Where J2 represents the second load (wet load), J1 represents the first load (dry load), R1 represents the maximum absorption of the conventional fabric, and J0 represents a constant.

The processor190may identify that the waterproof fabric is included in the laundry based on the fact that the inequality of [Equation 9] is satisfied. For example, the processor190may identify that the laundry includes the waterproof fabric based on the ratio of the second load to the first load being greater than the maximum absorption of the conventional fabric.

Further, the processor190may identify that the waterproof fabric is not included in the laundry, based on the fact that the inequality of [Equation 9] is not satisfied. For example, the processor190may identify that the waterproof fabric is not included in the laundry based on the ratio of the second load to the first load being less than or equal to the maximum absorption of the conventional fabric.

In addition, in response to a sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify whether the waterproof fabric is not included in the laundry based on the rotational acceleration caused by the dry load and the rotational acceleration of the wet load.

For example, the processor190may identify that the waterproof fabric is included in the laundry based on a ratio of the amplitude of the rotational acceleration of the dry load to the amplitude of the rotational acceleration of the wet load being greater than the maximum absorption of the conventional fabric. In addition, the processor190may identify that the waterproof fabric is not included in the laundry based on the ratio of the amplitude of the rotational acceleration of the dry load to the amplitude of the rotational acceleration of the wet load being equal to or less than the maximum absorption of the conventional fabric.

In response to determining that the laundry does not include the waterproof fabric (no in1240), the washer100may rotate the motor at a third speed (1250).

The processor190may control the motor drive200to rotate the drum130at the third speed based on determining that the laundry does not include the waterproof fabric. The third speed may be greater than the second speed, and may be a rotational speed of the drum130for measuring the wet load accommodated in the drum130. For example, the third speed may be a rotational speed between the first resonance section and the second resonance section of the tub120or may be greater than the rotational speed corresponding to the second resonance section.

As illustrated inFIG.15, the processor190may control the motor drive200to allow the rotational speed of the motor140to reach the third speed V3between time T3and time T4. The motor drive200may provide the motor140with a third driving current I3for increasing the rotational speed of the motor140between time T3and time T4. In response to the third driving current I3, the rotational acceleration of the motor140may increase to a third acceleration A3between time T3and time T4.

The washer100may add a sinusoidal current to the driving current supplied to the motor140(1260).

Operation1260may be the same as operation1030illustrated inFIG.7. For example, the processor190may control the motor drive200to allow a sinusoidal waveform to be superimposed on the driving current supplied to the motor140.

As illustrated inFIG.15, the processor190may provide a target speed command including a sinusoidal waveform or a load measurement command for load measurement to the motor drive200between time T4and time T5. The motor drive200may supply a fourth driving current I4including a sinusoidal current to the motor140between time T4and time T5. In response to the fourth driving current I4, the rotational acceleration of the motor140may be a fourth acceleration A4in the form of a sinusoidal wave between time T4and time T5.

The washer100may identify the magnitude of the third load based on the driving current and the rotational acceleration (1270).

Operation1270may be the same as operation1040and operation1050illustrated inFIG.7. For example, the processor190may identify the magnitude of the third load (wet load) accommodated in the drum130based on the driving current value and the rotational acceleration value obtained for each sampling period.

In addition, in response to a sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify the magnitude of the third load (wet load) accommodated in the drum130based on the rotational acceleration value obtained for each sampling period.

The third load (wet load) may indicate the weight of laundry measured during the drum130is rotated at the third speed V3. Due to the rotation of the drum130, some of the water may be separated from the laundry. Accordingly, the third load may be less than the second load measured during the drum130is rotated at the second speed V2which is less than the third speed V3.

The washer100may identify whether the waterproof fabric is included in the laundry based on the size of the third load (1280).

The processor190may identify whether or not the waterproof fabric is included in the laundry based on the comparison between the dry load (first load) and the wet load (third load).

Operation1280may be similar to operation1240.

For example, the processor190may identify that the laundry includes the waterproof fabric based on the ratio of the third load to the first load being greater than the maximum absorption of the conventional fabric. Further, the processor190may identify that the waterproof fabric is not included in the laundry based on the ratio of the second load to the first load being less than or equal to the maximum absorption of the conventional fabric.

In addition, in response to a sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify that the laundry does not include a waterproof fabric based on the rotational acceleration of the dry load and the rotational acceleration of the wet load.

In response to determining that the laundry does not include the waterproof fabric (no in1280), the washer100may rotate the motor at the fourth speed (1290).

The processor190may control the motor drive200to rotate the drum130at a fourth speed based on determining that the laundry does not include the waterproof fabric.

The fourth speed may represent a rotational speed of the drum130for spin-drying laundry not including a waterproof fabric. For example, the fourth speed may be approximately 1000 rpm or more.

In response to determining that the laundry includes the waterproof fabric (yes in1240or yes in1280), the washer100may rotate the motor at the fourth speed (1295).

The processor190may control the motor drive200to rotate the drum130at a fifth speed based on determining that the laundry includes the waterproof fabric.

The fifth speed may represent a rotational speed of the drum130for spin-drying laundry including the waterproof fabric, and may be less than the fourth speed. For example, the fourth speed may be approximately 500 rpm.

As described above, the washer100may identify the magnitude of the wet load while rotating the drum130for the spin-drying. Further, the washer100may identify whether the laundry includes the waterproof fabric based on the comparison between the dry load and the wet load.

Accordingly, the washer100may prevent or suppress the vibration of the drum130due to the unbalance of the load by the waterproof fabric.

FIG.16illustrates a method of identifying a moisture content of laundry during spin drying of the washer according to an embodiment of the disclosure.FIG.17illustrates a rotational speed, a rotational acceleration and a driving current by the method illustrated inFIG.16.

A method1300of identifying the moisture content of laundry accommodated in the drum130is described with reference toFIGS.16and17.

The washer100may rotate the motor140at a fourth speed (or fifth speed) (1310).

The processor190may control the motor drive200to rotate the drum130at the fourth speed (or fifth speed) during the spin-drying. The fourth speed (or fifth speed) may represent a final rotational speed (maximum rotational speed) for separating water from laundry. For example, in response to the laundry not including the waterproof fabric, the processor190may rotate the motor140at 1000 rpm or more. In addition, in response to the laundry including the waterproof fabric, the processor190may rotate the motor140at approximately 500 rpm.

As illustrated inFIG.17, the processor190may control the motor drive200to allow the rotational speed of the motor140to reach the fourth speed V4between time T1and time T2. The motor drive200may provide the motor140with a fifth driving current I5for increasing the rotational speed of the motor140between time T1and time T2. In response to the fifth driving current I5, the rotational acceleration of the motor140may increase to a fifth acceleration A5between time T1and time T2.

The washer100may add a sinusoidal current to the driving current supplied to the motor140(1320).

Operation1320may be the same as operation1030illustrated inFIG.7.

For example, the processor190may control the motor drive200to allow a sinusoidal waveform to be superimposed on the driving current supplied to the motor140.

As illustrated inFIG.17, the processor190may provide a target speed command including a sinusoidal waveform or a load measurement command for load measurement to the motor drive200between time T2and time T3. The motor drive200may supply a sixth driving current I6including a sinusoidal current to the motor140between time T2and time T3. In response to the sixth driving current I6, the rotational acceleration of the motor140may be a sixth acceleration A6in the form of a sinusoidal wave between the time T2and the time T3.

The washer100may identify the magnitude of the fourth load based on the driving current and the rotational acceleration (1330).

Operation1330may be the same as operation1040and operation1050illustrated inFIG.7. For example, the processor190may identify the magnitude of the fourth load, which is spin-dried, based on the driving current value and the rotational acceleration value obtained for each sampling period.

Further, in response to a sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify the magnitude of the fourth load based on the rotational acceleration value obtained for each sampling period.

The fourth load may represent the weight of the laundry from which water is separated by the drum130that is rotated at high speed. Accordingly, the fourth load may be greater than the first load indicating the weight of the laundry that does not absorb water, and may be less than the second or third load indicating the weight of the laundry before spin-drying.

The washer100may identify whether the laundry is sufficiently spin-dried based on the magnitude of the fourth load (1340).

The processor190may identify whether the laundry is sufficiently spin-dried based on the comparison between the first load and the fourth load.

As the spin-drying of laundry proceeds, the magnitude of the fourth load may decrease. In addition, as the spin-drying of the laundry proceeds, a ratio of the magnitude of the fourth load to the magnitude of the first load may decrease.

Accordingly, the processor190may identify the degree of spin-drying of laundry based on a ratio of the magnitude of the fourth load to the magnitude of the first load.

For example, the processor190may identify whether the laundry is sufficiently spin-dried based on [Equation 10].
J4<R2J1+J0.  [Equation 10]

Where J4 represents the fourth load, J1 represents the first load (dry load), R2 represents the reference moisture content for terminating the spin-drying, and J0 represents a constant.

The processor190may identify that the laundry is sufficiently spin-dried based on a fact that the inequality of [Equation 10] is satisfied. In other words, the processor190may identify that the laundry is sufficiently spin-dried, based on the weight ratio of water included in the spin-dried load being less than the reference moisture content.

In addition, the processor190may identify that additional spin-drying of laundry is required based on the fact that the inequality of [Equation 10] is not satisfied. In other words, the processor190may identify that the laundry is not sufficiently spin-dried based on the fact that the weight ratio of water included in the spin-dried load is greater than the reference moisture content.

In addition, in response to a sinusoidal current, which has a predetermined amplitude, being added to the driving current, the processor190may identify whether the laundry is sufficiently spin-dried based on the rotational acceleration of the dry load and the rotational acceleration of the wet load.

In response to identifying that the laundry is not sufficiently spin-dried (no in1340), the washer100may repeat to identify the fourth load and identify whether the laundry is sufficiently spin-dried.

In response to identifying that the laundry is sufficiently spin-dried (yes in1340), the washer100may decrease the rotational speed of the motor140(1350).

The processor190may identify that the laundry is sufficiently spin-dried based on the weight ratio of water included in the spin-dried load being less than the reference moisture content. Accordingly, the processor190may terminate the spin-drying. Accordingly, power consumption caused by the spin-drying may be reduced.

As described above, the washer100may identify the magnitude of the load during the spin-drying. Further, the washer100may identify whether the laundry is sufficiently spin-dried based on the magnitude of the load identified during the spin-drying.

Accordingly, the washer100may prematurely terminate the spin-drying according to the degree to which the laundry is spin-dried, thereby reducing power consumption caused by the spin-drying.

FIG.18illustrates a method of identifying a moisture content of laundry during spin drying of the washer according to an embodiment of the disclosure.

A method1400of identifying the moisture content of laundry contained in the drum130is described with reference toFIG.18.

The washer100may rotate the motor140at a fourth speed (1410). The washer100may add a sinusoidal current to the driving current supplied to the motor140(1420). The washer100may identify the magnitude of the fourth load based on the driving current and the rotational acceleration (1430).

Operations1410,1420, and1430may be the same as operations1310,1320, and1330illustrated inFIG.16, respectively.

The washer100may rotate the motor140at a sixth speed (1440). The washer100may add a sinusoidal current to the driving current supplied to the motor140(1450). The washer100may identify a magnitude of a fifth load based on the driving current and the rotational acceleration (1460).

The sixth speed may be different from or the same as the fourth speed.

Operations1440,1450, and1460may be the same as operations1310,1320, and1330illustrated inFIG.16, respectively.

The washer100may identify whether the laundry is sufficiently spin-dried based on the magnitude of the fourth load and the magnitude of the fifth load (1470).

The processor190may identify whether the laundry is sufficiently spin-dried based on the comparison between the fourth load and the fifth load.

As the spin-drying of laundry progresses, the magnitude of the wet load may be reduced. In other words, the magnitude of the fifth load may be less than the magnitude of the fourth load.

At this time, the small difference between the magnitude of the fourth load and the magnitude of the fifth load may indicate that the spin-drying due to the rotation of the drum130is saturated. Accordingly, in response to the difference between the magnitude of the fourth load and the magnitude of the fifth load being small, the processor190may identify whether the laundry is sufficiently spin-dried.

For example, the processor190may identify whether the laundry is sufficiently spin-dried in response to the ratio of the difference between the magnitude of the fourth load and the magnitude of the fifth load to the magnitude of the fourth load being less than a reference value.

In response to identifying that the laundry is not sufficiently spin-dried (no in1470), the washer100may repeat to identify the fourth load and the fifth load and identify whether the laundry is sufficiently spin-dried.

In response to identifying that the laundry is sufficiently spin-dried (yes in1470), the washer100may reduce the rotational speed of the motor140(1480).

The processor190may terminate the spin-drying.

As described above, the washer100may identify the magnitude of the load during the spin-drying. Further, the washer100may identify whether the laundry is sufficiently spin-dried based on the magnitude of the load identified during the spin-drying.

Accordingly, the washer100may prematurely terminate the spin-drying according to the degree to which the laundry is spin-dried, thereby reducing power consumption caused by the spin-drying.

A washer according to an embodiment may include a drum, a motor connected to the drum through a rotating shaft, a motor drive operatively connected to the motor, and a processor operatively connected to the motor drive. The processor may be configured to rotate the motor at a target speed and to determine a magnitude of a load accommodated in the drum while changing a rotational speed of the motor within a predetermined range.

The processor may be configured to periodically change the rotational speed of the motor within 5% of the target speed.

The processor may be configured to periodically change within 0.5% of the rotational speed of the motor during spin-drying.

Accordingly, the washer may identify the magnitude of the load in the high speed section as well as the low speed section because the change in the rotational speed of the motor is minimized while determining the magnitude of the load.

The processor may be configured to control the motor drive to supply a driving current including a sinusoidal current to the motor, and to determine the magnitude of the load accommodated in the drum based on a change in the rotational speed of the motor caused by the driving current including the sinusoidal current.

The processor may further be configured to provide a target speed signal including a sinusoidal waveform to the motor drive so as to supply a driving current including a sinusoidal current to the motor.

Accordingly, without adding a component for measuring the magnitude of the load in the high-speed section, the washer may identify the magnitude of the load even in the high-speed section by the periodic change of the driving current.

The processor may further be configured to control the motor drive to supply a first drive current including the sinusoidal current to the motor before supplying water to the drum, and to adjust an amount of water supplied to the drum based on a value of a first rotational speed of the motor caused by the first driving current.

Accordingly, the washer may measure the magnitude of the dry load at an approximately predetermined speed without generating noise and vibration due to the operation for measuring the magnitude of the dry load.

The processor may be configured to control the motor drive to supply a second drive current including the sinusoidal current to the motor after supplying water to the drum, to control the motor drive to control the rotational speed of the motor based on a value of a second rotational speed of the motor caused by the second drive current, and to determine a magnitude of a load accommodated in the drum based on a ratio of the value of the first rotational speed to the value of the second rotational speed.

The processor may further be configured to identify a magnitude of a dry load accommodated in the drum based on a change in the first rotational speed of the motor, and to identify a magnitude of a wet load accommodated in the drum based on a change in the second rotational speed of the motor.

Accordingly, the washer may identify whether or not the waterproof laundry is accommodated in the drum, based on the comparison of the magnitude of the dry load and the magnitude of the wet load.

The processor may control the motor drive to control the rotational speed of the motor based on a ratio of the magnitude of the wet load to the magnitude of the dry load.

The processor may be configured to control the motor drive to rotate the motor at a first speed based on the ratio of the magnitude of the wet load to the magnitude of the dry load being less than a first reference value, and to control the motor drive to rotate the motor at a second speed, which is less than the first speed, based on the ratio of the magnitude of the wet load to the magnitude of the dry load being equal to or greater than the first reference value.

Accordingly, the washer may reduce vibration and noise caused by the waterproof laundry by controlling the rotational speed of the drum during the spin-drying.

The processor may further be configured to control the motor drive to supply a third drive current including the sinusoidal current to the motor during rotating the motor at a third speed for spin-drying, and to identify a magnitude of spin-dried load of the drum based on a value of a third rotational speed of the motor including a sinusoidal waveform caused by the third driving current.

The processor may further be configured to control the motor drive to control the rotational speed of the motor based on the magnitude of the spin-dried load.

The processor may further be configured to control the motor drive to reduce the rotational speed of the motor based on a ratio of the magnitude of the spin-dried to the magnitude of the dry load being less than a second reference value, and to control the motor drive to maintain the rotational speed of the motor based on the ratio of the magnitude of the spin-dried to the magnitude of the dry load being equal to or greater than the second reference value.

Accordingly, the washer may identify whether spin-drying is completed while minimizing the change in the rotational speed of the drum during spin-drying at the minimum speed.

As is apparent from the above description, a washer and a control method thereof may measure a load accommodated in a drum while minimizing a change in a rotational speed of the drum. Accordingly, the washer may accurately measure the load.

Further, a washer and a control method thereof may measure a load accommodated in a drum even during high-speed rotation. Accordingly, the washer may measure the load and a change in the load during a spin-drying cycle

Meanwhile, the disclosed embodiments may be embodied in the form of a recording medium storing instructions executable by a computer. The instructions may be stored in the form of program code and, when executed by a processor, may generate a program module to perform the operations of the disclosed embodiments. The recording medium may be embodied as a computer-readable recording medium.

The computer-readable recording medium includes all kinds of recording media in which instructions which can be decoded by a computer are stored. For example, there may be a Read Only Memory (ROM), a Random Access Memory (RAM), a magnetic tape, a magnetic disk, a flash memory, and an optical data storage device.

Storage medium readable by machine, may be provided in the form of a non-transitory storage medium. “Non-transitory” means that the storage medium is a tangible device and does not contain a signal (e.g., electromagnetic wave), and this term includes a case in which data is semi-permanently stored in a storage medium and a case in which data is temporarily stored in a storage medium.

The method according to the various disclosed embodiments may be provided by being included in a computer program product. Computer program products may be traded between sellers and buyers as commodities. Computer program products are distributed in the form of a device-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or are distributed directly or online (e.g., downloaded or uploaded) between two user devices (e.g., smartphones) through an application store (e.g., Play Store™). In the case of online distribution, at least a portion of the computer program product (e.g., downloadable app) may be temporarily stored or created temporarily in a device-readable storage medium such as the manufacturer's server, the application store's server, or the relay server's memory.

Although a few embodiments of the disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.