WASHING MACHINE AND CONTROL METHOD THEREOF

A washing machine according to an aspect of the disclosure includes: a drum; a tub accommodating the drum and storing water; a drum motor configured to provide a rotation force to the drum; a water supplier configured to supply water to the tub; a hot air supplier configured to supply hot air to the drum; a current sensor configured to output a current signal corresponding to a magnitude of current applied to the drum motor; and a controller configured to perform a washing operation while controlling the water supplier and the drum motor, and perform a drying operation while controlling the hot air supplier and the drum motor.

BACKGROUND

The disclosure relates to a washing machine capable of washing and drying laundry, such as clothes, etc., and a control method thereof.

2. Description of the Related Art

A washing machine is a machine for washing clothes, and generally, the washing machine includes a tub for storing water and a drum for generating mechanical energy inside the tub to separate dirt from laundry.

There is a washing machine having a drying function. The washing machine includes a dryer for drying laundry by blowing hot air generated by a drying heater into an accommodating space where the laundry is accommodated, and the washing machine can perform a dehydrating function and a drying function in connection with a washing function.

The washing machine includes a sensor (for example, a humidity sensor) inside the drum, and uses a method of determining a dried state of laundry through the sensor directly contacting the laundry.

However, the method may generate an error in determining a dried state of laundry according to an installation location of the sensor and irregular movements of the laundry, which leads to incomplete drying of the laundry or a waste of energy due to excessive drying.

SUMMARY

In accordance with an aspect of the disclosure, a washing machine includes: a drum to receive an object, the drum being rotatable; a tub to accommodate the drum and to receive water; a drum motor configured to provide a rotation force to the drum, for the drum to rotate within the tub; a water supplier configured to supply the water to the tub; a hot air supplier configured to supply hot air to the drum; a current sensor configured to output a current signal based on a magnitude of current applied to the drum motor to rotate the drum; and a controller configured to perform a washing operation while controlling the water supplier and the drum motor, and a drying operation while controlling the hot air supplier and the drum motor, wherein the controller is configured determine a dryness of the object, accommodated in the drum, based on the current signal received while performing the drying operation, obtain an average measurement value corresponding to the dryness of the object by calculating an average of a plurality of measurement values measured during a preset time period, compare a first average measurement value with a second average measurement value obtained in succession to the first average measurement value, determine an event is generated based on a determination that the second average measurement value is greater than or equal to the first average measurement value, and control the hot air supplier based on the number of times by which the event is generated.

The controller may be further configured to control the hot air supplier based on a determination that the event is sequentially generated.

The controller may be further configured to control the hot air supplier based on a determination that a preset number of events have been sequentially generated, and erase the number of previously generated events according to a determination that the second average measurement value is smaller than the first average measurement value.

The washing machine may further include a first temperature sensor configured to measure temperature of air discharged from the drum and a second temperature sensor configured to measure temperature of air supplied from the hot air supplier to the drum, wherein the controller may be further configured to control the hot air supplier based on a difference between first temperature measured by the first temperature sensor and second temperature measured by the second temperature sensor, upon generation of the event.

The controller may be further configured to compare the difference between the first temperature and the second temperature with a preset reference value.

The controller may be further configured to determine an execution time of the washing operation based on the current signal.

The controller may be further configured to determine an amount of water to be supplied to the tub based on the current signal, and control the water supplier according to the amount of water.

The controller may be further configured to rotate the drum at preset revolutions per minute (rpm) before starting the washing operation to obtain a first magnitude value of motor current applied to the drum motor at the preset rpm, rotate the drum at the preset rpm during the drying operation to obtain a second magnitude value of motor current applied to the drum motor at the preset rpm, and finish the drying operation according to a determination that a difference between the first magnitude value and the second magnitude value is smaller than or equal to a preset current difference and the number of sequentially generated events reaches a preset number.

The controller may be further configured to rotate the drum at preset revolutions per minute (rpm) before starting the washing operation to obtain a first magnitude value of motor current applied to the drum motor at the preset rpm, rotate the drum at the preset rpm during the drying operation to obtain a second magnitude value of motor current applied to the drum motor at the preset rpm, and finish the drying operation according to a determination that a difference between the first magnitude value and the second magnitude value is smaller than or equal to a preset current difference and a difference between temperature measured by the first temperature sensor and temperature measured by the second temperature sensor is smaller than or equal to a first temperature difference.

The controller may be further configured to turn off a heater and turn on a fan to perform a cooling operation after finishing the drying operation.

In accordance with an aspect of the disclosure, a method for controlling a washing machine with a drying function, the washing machine including a drum to receive an object, the drum being rotatable, a tub to accommodate the drum and to receive water, a drum motor configured to provide a rotation force to the drum, for the drum to rotate within the tub, a water supplier configured to supply the water to the tub, a hot air supplier configured to supply hot air to the drum, and a current sensor configured to output a current signal based on a magnitude of current applied to the drum motor to rotate the drum, the method includes: determining a dryness of the object, accommodated in the drum, based on the current signal received while performing the drying operation; obtaining an average measurement value corresponding to the dryness of the object by calculating an average of a plurality of measurement values measured during a preset time period; comparing a first average measurement value with a second average measurement value obtained in succession to the first average measurement value; determining an event is generated based on a determination that the second average measurement value is greater than or equal to the first average measurement value; and controlling the hot air supplier based on the number of times by which the event is generated.

The controlling of the hot air supplier may include controlling the hot air supplier according to a determination that the event is sequentially generated.

The method may further include controlling the hot air supplier based on a determination that a preset number of events have been sequentially generated, and erasing the number of previously generated events according to a determination that the second average measurement value is smaller than the first average measurement value.

The washing machine may further include a first temperature sensor configured to measure temperature of air discharged from the drum and a second temperature sensor configured to measure temperature of air supplied from the hot air supplier to the drum, and the controlling of the hot air supplier may include controlling the hot air supplier based on a difference between first temperature measured by the first temperature sensor and second temperature measured by the second temperature sensor, upon generation of the event.

The controlling of the hot air supplier may further include comparing the difference between the first temperature and the second temperature with a preset reference value.

The method may further include determining an execution time of the washing operation based on the current signal.

The method may further include determining an amount of water to be supplied to the tub based on the current signal, and controlling the water supplier according to the amount of water.

The method may further include: rotating the drum at preset revolutions per minute (rpm) before starting the washing operation to obtain a first magnitude value of motor current applied to the drum motor at the preset rpm, rotating the drum at the preset rpm during the drying operation to obtain a second magnitude value of motor current applied to the drum motor at the preset rpm, and finishing the drying operation according to a determination that a difference between the first magnitude value and the second magnitude value is smaller than or equal to a preset current difference and the number of sequentially generated events reaches a preset number.

The method may further include: rotating the drum at preset revolutions per minute (rpm) before starting the washing operation to obtain a first magnitude value of motor current applied to the drum motor at the preset rpm, rotating the drum at the preset rpm during the drying operation to obtain a second magnitude value of motor current applied to the drum motor at the preset rpm, and finishing the drying operation according to a determination that a difference between the first magnitude value and the second magnitude value is smaller than or equal to a preset current difference and a difference between temperature measured by the first temperature sensor and temperature measured by the second temperature sensor is smaller than or equal to a first temperature difference.

The method may further include turning off a heater and turning on a fan to perform a cooling operation after finishing the drying operation.

DETAILED DESCRIPTION

Like reference numerals will refer to like components throughout this specification. This specification does not describe all components of the embodiments, and general information in the technical field to which the present disclosure belongs or overlapping information between the embodiments will not be described. As used herein, the terms “portion”, “part, “module, “member” or “block” may be implemented as software or hardware, and according to embodiments, a plurality of “portions”, “parts, “modules, “members” or “blocks” may be implemented as a single component, or a single “portion”, “part, “module, “member” or “block” may include a plurality of components.

It will be understood that when a certain part is referred to as being “connected” to another part, it can be directly or indirectly connected to the other part. When a part is indirectly connected to another part, it may be connected to the other part through a wireless communication network.

Also, it will be understood that when the terms “includes,” “comprises,” “including,” and/or “comprising,” when used in this specification, specify the presence of a stated component, but do not preclude the presence or addition of one or more other components.

In the entire specification, it will also be understood that when an element is referred to as being “on” or “over” another element, it can be directly on the other element or intervening elements may also be present.

Also, it will be understood that, although the terms “first”, “second”, etc., may be used herein to describe various components, these components should not be limited by these terms. The above terms are used only to distinguish one component from another.

Also, it is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

Reference numerals used in operations are provided for convenience of description, without describing the order of the operations, and the operations can be executed in a different order from the stated order unless a specific order is definitely specified in the context.

Therefore, it is an aspect of the disclosure to provide a washing machine capable of accurately determining a dried state of laundry through a non-contact sensor, and a method for controlling the washing machine.

FIG.1shows an outer appearance of a washing machine according to an embodiment of the disclosure.FIG.2is a side cross-sectional view of a washing machine according to an embodiment of the disclosure.FIG.3is an exploded view of a tub and a dryer included in a washing machine according to an embodiment of the disclosure.

Referring toFIGS.1,2, and3, a washing machine100may include: a cabinet101, a tub110, a drum120, a drum motor130, a water supplier140, a water drain150, a detergent supplier160, and a dryer200.

The washing machine100according to an embodiment of the disclosure may be an apparatus capable of performing a dry operation. The washing machine100may dry laundry by supplying hot air into the drum120, unlike an existing washing machine that performs only a washing operation and a dehydrating operation. The washing machine100may be a washing machine with a drying function, and configurations and operations which will be described below may also be applied to a drying apparatus for performing only a drying operation.

The cabinet101may accommodate configurations included in the washing machine100. For example, the cabinet101may accommodate the tub110, the drum120, the drum motor130, the water supplier140, the water drain150, the detergent supplier160, and the dryer200.

In a front center of the cabinet101, an entrance101athrough which a user puts laundry or takes laundry out may be formed.

In the entrance101a, a door102for opening and closing the entrance101amay be provided. The door102may be rotatably installed on the cabinet101by a hinge. In a closed state of the entrance101a, the door102may be locked by a locking device.

In a front upper portion of the cabinet101, a control panel103including a user inputter for obtaining a user input for the washing machine100from the user and a display displaying operation information of the washing machine100may be provided.

The tub110may be provided inside the cabinet101, and accommodate water for washing and/or rinsing.

The tub110may include a tub front part111having a front side in which an opening111ais formed, and a tub rear part112being in a shape of a cylinder of which a rear side is closed.

In the front side of the tub front part111, the opening111amay be provided to enable a user to put laundry into the drum120provided inside the tub110or take laundry out of the drum120.

In the opening111aof the tub front part111, a diaphragm113may be provided, and the diaphragm113may connect the opening111ato the entrance101aof the cabinet101. In an upper portion of the diaphragm113, a discharge port113amay be provided to discharge air heated and dried by the dryer200into the tub110or the drum120during a drying operation.

A lower portion of the tub front part111may be connected to a drain pipe151extending to a drain pump152.

In a rear wall112aof the tub rear part112, a bearing housing112eand a bearing112dfor rotatably fixing the drum motor130may be provided.

In a lower portion of the tub rear part112, a tub heater114may be provided. The tub heater114may heat water accommodated in the tub110. The tub heater114may operate to raise temperature of water accommodated in the tub110up to temperature set by a user.

In an upper portion of the tub rear part112, an inlet port112cfor sucking inside air of the tub110or the drum120into the dryer200during a drying operation may be provided. In a side wall112bof the tub rear part112, a condensing duct240for guiding inside air of the tub110or the drum120to the inlet port112cduring a drying operation may be formed.

The condensing duct240will be described in more detail below.

The drum120may be rotatably provided inside the tub110, and accommodate laundry.

The drum120may include a drum body121being in a shape of a cylinder, a drum front part122provided in a front side of the drum body121, and a drum rear part123provided in a rear side of the drum body121.

In an inner surface of the drum body121, a through hole121aconnecting inside of the drum120to inside of the tub110, and a lifter121bfor raising laundry upward while the drum120rotates may be provided. In the drum front part122, an opening122afor enabling a user to put laundry into the drum120or take laundry out of the drum120may be provided. The drum rear part123may be connected to a shaft131of the drum motor130for rotating the drum120.

The drum motor120may be provided on an outer side of the rear wall112aof the tub110, and connected to the drum120through the shaft131. The shaft131may penetrate the rear wall112aof the tub110, and the shaft131may also be rotatably supported by the bearing112dand the bearing housing112eprovided on the rear wall112aof the tub110.

The drum motor130may include a stator132fixed on the outer side of the rear wall112aof the tub rear part112, and a rotor133being rotatable and connected to the shaft131. The rotor133may rotate through a magnetic interaction with the stator132, and a rotation of the rotor133may be transferred to the drum120through the shaft131.

The drum motor130may include, for example, a BrushLess Direct Current (BLDC) motor capable of easily controlling revolutions per minute (rpm) or a Permanent Magnet Synchronous Motor (PMSM).

The water supplier140may be provided above the tub110, and supply water to the tub110or the drum120.

The water supplier140may include a water supply pipe141connected to an external water supply source to supply water to the tub110, and a water supply valve142provided on the water supply pipe141.

The water supply pipe141may extend from the external water supply source to a detergent case161, and guide water to the tub110via the detergent case161.

The water supply valve142may supply water from the external water supply source to the tub110or block water from being supplied from the external water supply source to the tub110, in response to an electrical signal. The water supply valve142may include, for example, a solenoid valve that is opened or closed in response to an electrical signal.

The water drain150may be provided below the tub110, and discharge water accommodated in the tub110or the drum120to outside.

The water drain150may include the drain pipe151extending from the tub110to the outside of the cabinet101, and the drain pump152provided on the drain pipe151. The drain pump152may pump water of the drain pipe151to the outside of the cabinet101.

The detergent supplier160may be provided above the tub110, and supply a detergent to the tub110or the drum120.

The detergent supplier160may include the detergent case161storing a detergent, and a mixing pipe162connecting the detergent case161to the tub110.

The detergent case161may be connected to the water supply pipe141, and water supplied through the water supply pipe141may be mixed with the detergent stored in the detergent case161. A mixture of the detergent and water may be supplied to the tub110via the mixing pipe162.

The dryer200may be provided on the tub110and the rear wall112aof the tub110to dry laundry accommodated in the drum120.

The dryer200may include a heating duct210, a filter housing220, a connecting pipe230, and the condensing duct240.

The heating duct210may be provided on the tub110, and air sucked from the tub110may be heated by passing through the heating duct210.

The heating duct210may extend from a rear side of the tub110to a front side of the tub110. A front side of the heating duct210may be connected to the discharge port113a, and a rear side of the heating duct210may be connected to the filter housing220.

The heating duct210may be in a shape of a tube extending from the rear side of the tub110to the front side of the tub110, and include a duct upper plate211and a duct lower plate212. However, the shape of the heating duct210is not limited to that shown inFIG.3.

A fan213, a fan motor214, and a duct heater215may be provided inside the heating duct210, that is, between the duct upper plate211and the duct lower plate212.

The fan motor214may be connected to the fan213through a rotation shaft, and provide a rotation force to the fan213.

The fan213may be positioned in an opening212aof the duct lower plate212, and the fan213may rotate to cause air to circulate between the tub110and the heating duct210. For example, the fan213may suck inside air of the tub110or the drum120from the rear side of the tub110to the heating duct210, and discharge air of the heating duct210to the front side of the tub110.

The duct heater215may heat air passing through the heating duct210. Air of the tub110may be sucked into the heating duct210by the fan213, and flow inside the heating duct210. The duct heater215may heat air flowing along the heating duct210. The heated air may be discharged to the tub110by the fan213.

The filter housing220may be provided between the heating duct210and the tub110, and guide air sucked from the tub110through the connecting pipe230to the heating duct210.

The filter housing220may be connected to the heating duct210. Also, the filter housing220may be connected to the tub110through the connecting pipe230.

The filter housing220may have a shape resulting from coupling two cylinders with each other. The upper cylinder may be connected to the heating duct210, and the lower cylinder may be connected to the connecting pipe230. A diameter of the upper cylinder may be different from that of the lower cylinder. A central axis of the upper cylinder may be not identical to that of the lower cylinder, although the central axis of the upper cylinder may be in parallel to that of the lower cylinder. However, the shape of the filter housing220is not limited to that shown inFIG.3.

A filter221for filtering dust included in air sucked from the tub110may be provided inside the filter housing220. For example, the filter221may be positioned at a portion where the upper cylinder is connected to the lower cylinder.

A washing water nozzle222for spraying water to wash the filter221may be provided inside the filter housing220. The washing water nozzle222may be connected to the external water supply source through a washing water pipe223, and a washing water valve224may be provided on the washing water pipe223. The washing water valve224may supply water to the washing water nozzle222or block water from being supplied to the washing water nozzle222, in response to an electrical signal. The washing water valve224may include, for example, a solenoid valve that is opened or closed in response to an electrical signal.

The connecting pipe230may be provided between the filter housing220and the tub110, and guide air sucked from the tub110to the tub110.

One end of the connecting pipe230may be connected to the condensing duct240. More specifically, the connecting pipe230may be connected to the inlet port112cof the tub110. The other end of the connecting pipe230may also be connected to the filter housing220.

The connecting pipe230may be in a shape of a bellows to prevent vibrations of the tub110from being transferred to the filter housing220. However, the shape of the connecting pipe230is not limited to that shown inFIG.3.

FIG.4is a control block diagram of a washing machine according to an embodiment of the disclosure.

The washing machine100may include a user inputter171, a display172, a current sensor173, a first temperature sensor174, a second temperature sensor175, a motor driving circuit180, the drum motor130, the water supply valve142, the drain pump152, the fan motor214, the tub heater114, the duct heater215, the washing water valve224, a condensed water valve246, and a controller190. Also, the washing machine100may perform an operation of sensing an amount of laundry, a washing operation, a rinsing operation, and a drying operation.

The washing machine100may perform a washing operation while controlling the water supplier140and the drum motor130, and perform a drying operation while controlling a hot air supplier212and the drum motor130.

The washing machine100may supply hot air to the drum20through the hot air supplier212including the fan motor214and the duct heater215. Hot air heated by the duct heater215may be supplied into the drum20by air current formed by the fan motor214.

The drum motor130, the water supply valve142, the drain pump152, the fan motor214, the tub heater114, the duct heater215, the washing water valve224, and the condensed water valve246have been described above with reference toFIG.3.

The user inputter171may be provided on the control panel103of the cabinet101, and include a dial171afor obtaining a user input by a rotation, and an input button for obtaining a user input by a reciprocating movement.

A user may select any one from among a plurality of washing courses by rotating the dial171a. The washing machine100may include a plurality of different washing courses for washing, for example, different kinds of laundry. The different washing courses may include different washing times, different rinsing times, and different dehydrating times.

The input button171bmay include a washing button for adjusting a washing time for which the washing machine1washes laundry, a rinsing button for adjusting the number of times of rinsing by which the washing machine100rinses laundry, and a dehydrating button for adjusting a dehydrating time for which the washing machine100dehydrates laundry. Also, the button171bmay include a power button for receiving power from an external power source or blocking power supplied from the external power source, and an operation button for starting or pausing an operation of the washing machine100.

The dial171aand the button171bmay transfer an electrical signal (voltage or current) corresponding to a user input received from a user to the controller190, in response to the user input.

The display172may be provided on the control panel103of the cabinet101, and display an operation state of the washing machine100or a user's control command. For example, the display172may display a washing course selected by a user, and display a time left until operation completion of the washing machine100while the washing machine100operates.

The display172may include a Light Emitting Diode (LED) panel, an Organic Light Emitting Diode (OLED) panel, or a Liquid Crystal Display (LCD) panel.

The display172may adopt a touch screen panel (TSP) for receiving a control command from a user and displaying operation information corresponding to the received control command.

As such, the display172may receive a display control signal from the controller190, and display an image corresponding to the display control signal.

The current sensor173may sense motor current applied to the drum motor130for providing a rotation force to the drum120. The drum motor130may consume more power according to an increase of a load caused by a weight of laundry at constant rpm, and consume less current according to a decrease of a load upon a reduction of water included in laundry.

The current sensor173may provide a measurement value of motor current to the controller190at regular time intervals. The current sensor173may include a current transformer (CT) for proportionally reducing a magnitude of current, and an ampere meter for detecting a magnitude of current proportionally reduced. That is, a current sensor173may detect current by proportionally reducing a magnitude of current by using the current transformer and then measuring a magnitude of the current proportionally reduced. The current sensor173may output a current signal corresponding to a magnitude of current applied to the drum motor130, and provide the current signal to the controller190.

The first temperature sensor174may be positioned at a location at which air enters the dryer200.

The first temperature sensor174may measure temperature of low-temperature air, the temperature lowered from temperature of high-temperature air, entered the dryer200. Also, the first temperature sensor174may measure temperature of water accommodated in the tub110or temperature of inside air of the tub110or the drum120. For example, the first temperature sensor174may indirectly measure temperature of water accommodated in the tub110during a washing operation and/or a rinsing operation. Also, the first temperature sensor174may measure temperature of inside air of the tub110or the drum120during a drying operation. In other words, the first temperature sensor174may measure temperature of air discharged from the drum120.

The first temperature sensor174may include a thermistor. An electrical resistance value of the thermistor may change according to temperature, and the first temperature sensor174may transfer an electrical signal (voltage or current) corresponding to an electrical resistance value of the thermistor to the controller190.

The second temperature sensor175may be positioned at a location at which air is discharged from the dryer200.

The second temperature sensor175may measure temperature of high-temperature air, the temperature raised from temperature of low-temperature air, passed through the dryer200. For example, the second temperature sensor175may be installed around the duct heater215. More specifically, the second temperature sensor175may be positioned downstream of the duct heater215on flow of air during a heating operation. Also, the second temperature sensor175may measure inside temperature of the heating duct210. For example, the second temperature sensor175may measure temperature of air heated by the duct heater215during a drying operation. In other words, the second temperature sensor175may measure temperature of air that is supplied from the hot air supplier212to the drum120.

The second temperature sensor175may include a thermistor. An electrical resistance value of the thermistor may change according to temperature, and the second temperature sensor175may transfer an electrical signal (voltage or current) corresponding to an electrical resistance value of the thermistor to the controller190.

Meanwhile, the controller190may obtain information about a temperature difference based on temperature obtained through the first temperature sensor174and the second temperature sensor175. The controller190may determine a degree of progress of a drying operation based on the temperature difference, and determine a time required for the drying operation. A more detailed description will be given below.

The motor driving circuit180may be mounted on a printed circuit board installed around the drum motor130.

The motor driving circuit180may supply driving current to the drum motor130. The motor driving circuit180may convert alternating current power of an external power source into driving power for driving the drum motor130.

The motor driving circuit180may have various topologies according to a kind of the drum motor130.

For example, in a case which the drum motor130is a direct current motor, the motor driving circuit180may convert alternating current power supplied from an external power source into direct current power, and intermittently supply the direct current power to the drum motor130. In a case in which the drum motor130is a brushless direct current motor, the motor driving circuit180may convert alternating current power into direct current power, then convert the direct current power into alternating current power being in a form of a square wave, and supply the alternating current power being in the form of the square wave to the drum motor130. In a case in which the drum motor130is a permanent magnet synchronous motor, the motor driving circuit180may convert alternating current power into direct current power, then convert the direct current power into alternating current power being in a form of a sine wave and supply the alternating current power being in the form of the sine wave to the drum motor130. In a case in which the drum motor130is an induction motor, the motor driving circuit180may intermittently supply alternating current power supplied from an external power source to the drum motor130.

The controller190may be mounted, for example, on a printed circuit board provided on a rear surface of the control panel103.

The controller190may be electrically connected to the user inputter171, the current sensor173, the first temperature sensor174, the second temperature sensor175, the display172, the motor driving circuit180, the water supply valve142, the drain pump152, the fan motor214, the tub heater114, the duct heater215, the washing water valve224, and the condensed water valve246.

The controller190may control the display172, the motor driving circuit180, the fan motor214, and the duct heater215based on an output from the current sensor173.

The controller190may control the display172, the motor driving circuit180, the fan motor214, and the duct heater215based on outputs from the first temperature sensor174and the second temperature sensor175.

The controller190may control the display172, the motor driving circuit180, the fan motor214, and the duct heater215based on outputs from the current sensor173, the first temperature sensor174, and the second temperature sensor175.

The controller190may include a processor191for generating a control signal for controlling an operation of the washing machine100, and a memory192memorizing or storing a program and data for generating a control signal for controlling an operation of the washing machine100. The processor191and the memory192may be implemented as separate chips or a single chip. Also, the controller190may include a plurality of processors or a plurality of memories.

The processor191may process data and/or a signal according to a program provided from the memory192, and provide a control signal to individual configurations of the washing machine100based on a result of the processing.

The processor191may receive an electrical signal about a user input from the user inputter171, receive an electrical signal about current from the current sensor173, receive an electrical signal about temperature of air entered the dryer200from the first temperature sensor174, and receive an electrical signal about temperature of air discharged from the dryer200from the second temperature sensor175. The processor191may process the electrical signal about the user input, the electrical signal about the current, and the electrical signal about the temperature.

The processor191may identify a washing course selected by a user based on a user input. The processor191may determine rpm and an operation cycle (for example, an on time and an off time) of the drum120depending on the washing course selected by the user, and provide a motor signal for rotating the drum motor130to the motor driving circuit180according to the determined rpm and operation cycle.

During a drying operation, the processor191may provide a blow signal for sucking inside air of the tub110or the drum120to the dryer200to the fan motor214, provide a duct heating signal for heating air of the heating duct210to the duct heater215, provide a condensation signal for spraying water to the condensing duct240to the condensed water valve246, and provide a driving signal for rotating the drum120to the motor driving circuit180.

The processor191may include an operation circuit, a memory circuit, and a control circuit. The processor191may include a single chip or a plurality of chips. Also, the processor191may include a single core or a plurality of cores.

The memory192may memorize or store a program and data for controlling an operation of the washing machine100according to a washing course. For example, the memory192may memorize or store rpm of the drum120according to a washing course, and a washing time/number of times of rinsing/dehydration time according to a washing course.

The memory192may memorize a user input received through the dial171aand the input button171b, or information (for example, information about an operation being currently performed or a time left until operation completion of the washing machine100) about an operation of the washing machine100.

The memory192may include a volatile memory, such as a Static Random Access Memory (S-RAM) and a Dynamic Random Access Memory (D-RAM), and a non-volatile memory, such as a Read Only Memory (ROM) and an Erasable Programmable Read Only Memory (EPROM).

The memory192may include a single memory device or a plurality of memory devices.

The controller190may control individual configurations of the washing machine100to wash/rinse/dehydrate/dry laundry. The controller190may perform a washing operation, a rinsing operation, a dehydrating operation, and a drying operation.

According to an increase in amount of laundry, current that is supplied from the motor driving circuit180to the drum motor130may increase. The controller190may control the motor driving circuit180to rotate the drum120forward or backward, and measure current supplied from the motor driving circuit180to the drum motor130to measure an amount of laundry. Accordingly, the controller190may estimate the amount of laundry based on the current supplied from the motor driving circuit180to the drum motor130. Also, the controller190may estimate a dehydrated state or a dried state of laundry based on current supplied from the motor driving circuit180to the drum motor130.

The controller190may supply water and a detergent to the tub110. The controller190may open the water supply valve142to supply water to the tub110depending on the measured amount of laundry. By opening the water supply valve151, water may be supplied to the tub110via the detergent case161. Accordingly, a detergent may be supplied to the tub110together with water during a first water supply for washing.

The controller190may rotate the drum120at low rpm for washing. The controller190may control the motor driving circuit180to rotate the drum120at low rpm (for example, rpm between about 45 rpm and about 60 rpm). The controller190may control the motor driving circuit180to rotate the drum120alternately in a first direction and a second direction. While the drum120rotates alternately in the first direction and the second direction, laundry accommodated inside the drum120may roll along an inner wall of the drum120or be lifted and then fall. Foreign materials attached to the laundry may be separated from the laundry by physical actions caused by rolling and falling of the laundry and chemical actions of the detergent.

The controller190may discharge water stored in the tub110. The controller190may operate the drain pump152to discharge the water stored in the tub110. The water stored in the tub110may be pumped to the outside by the drain pump152.

The controller190may rotate the drum120at high rpm for midway dehydrating. The controller190may control the motor driving circuit180to rotate the drum120at high rpm (for example, rpm between about 1000 rpm and about 1100 rpm). While the drum120rotates at high rpm, the laundry accommodated inside the drum120may be located along the inner wall of the drum120, and water absorbed in the laundry may be separated from the laundry by a centrifugal force. The water separated from the laundry may pass through the through hole121aof the drum120and then be discharged to the outside via the tub110and the drain pipe151.

Thereafter, the controller190may perform a rinsing operation. The controller190may supply water to the tub110, and rotate the drum120at low rpm for rinsing. The controller190may discharge water stored in the tub110and rotate the drum120at high rpm for midway dehydrating.

Then, the controller190may perform a dehydrating operation. The controller190may rotate the drum120at high rpm.

Thereafter, the controller190may perform a drying operation.

The controller190may operate the duct heater215to heat inside air of the tub110or the drum120. In response to preset temperature of the inside air of the tub110, the controller190may operate the duct heater215, while controlling the motor driving circuit180to rotate the drum120at constant rpm (for example, rpm between about 45 rpm and about 60 rpm). The controller190may open the condensed water valve246to supply water to the condensing duct240.

Meanwhile, the disclosure relates to estimating a dried state of laundry during a drying operation based on current applied to the drum motor130and/or temperature of air circulating through the dryer200without any direct contact to the laundry. Hereinafter, a process of determining a dried state of laundry and determining a completion time of a drying operation will be described in detail with reference to flowcharts shown inFIGS.5,8,10,11, and12.

FIG.5is a flowchart illustrating a method for controlling a washing machine according to an embodiment of the disclosure,FIG.6is a graph showing a reduction of motor current over drying time of laundry, andFIG.7shows data obtained by applying filtering to the graph ofFIG.6. The embodiment ofFIG.5will be described in detail with reference toFIGS.6and7.

The controller190may control the drum motor130to rotate the drum120, in operation501. The washing machine100may rotate the drum120at constant rpm to apply hot air generated by the dryer200to the entire of laundry during a drying operation.

The current sensor173may sense motor current in operation502, and output a current signal. The controller190may obtain a measurement value of motor current for determining a dryness of an object to be dried, accommodated in the drum120, based on a current signal, at regular time intervals, in operation503. The current sensor173may output a current signal corresponding to a magnitude of current applied to the drum motor130, and transfer the current signal to the controller190. For example, the controller190may control the drum120to rotate at constant rpm, and obtain a measurement value of motor current applied to the drum motor130at time intervals of one minute. The measurement value may be a magnitude of current applied to the drum motor130. The smaller magnitude of current may represent the smaller measurement value, and the smaller measurement value may represent a smaller weight of an object to be dried according to the progress of drying.

Also, the controller190may calculate an average measurement value by calculating an average of a plurality of measurement values for a preset time period, in operation503. Because a measure value may include noise due to a rotation of the drum120and an external factor, an average measurement value obtained by calculating an average in a unit of a preset time period may be used to raise reliability.

Referring toFIG.6, a magnitude of motor current may be reduced over time during a drying operation, and, after the drying operation proceeds up to a certain degree, the magnitude of motor current may be no longer reduced or converge to a certain range. The reason may be because water of laundry is removed by the drying operation and accordingly, a weight of the laundry is reduced. The disclosure may determine a dried state of laundry based on the tendency. As shown in the drawings, a magnitude of motor current and a change in magnitude of motor current may depend on an initial weight of laundry.

Optionally, the controller190may perform filtering on the measurement value and/or the average measurement value, in operation504. The measurement value and/or average measurement value of the motor current may deviate from a range of normal values according to falling or an arrangement of fabric inside the drum120. Accordingly, the controller190may perform filtering on the measurement value and/or average measurement value of the motor current obtained at the regular time intervals. At this time, the filtering may remove noise by installing a separate hardware filter circuit or by performing a separate software method. The filter may include a low pass filter, a moving average filter, etc.

The controller190may sequentially obtain average measurement values, compare the average measurement values with each other, and generate an event based on a result of the comparison, in operation506. For example, the controller190may compare a first average measurement value with a second average measurement value obtained in succession to the first average measurement value and generate an event according to a determination that the second average measurement value is greater than or equal to the first average measurement value, in operations505and506. The event may be an index for determining a dried state, and may be sequentially accumulated upon satisfaction of a preset condition.

A reduction of an average measurement value over time may represent a reduction in weight of an object to be dried according to the progress of drying. In a case in which water contained in an object to be dried has been nearly completely removed, an average measurement value may converge to a certain value. That is, according to completion of drying, an average measurement value and/or a measurement value may tend to be no longer reduced, and completion of drying may be estimated based on the tendency.

Therefore, the controller190may generate an event according to a determination that the second average measurement value is greater than or equal to the second average measurement value. That the second average measurement value is equal to the first average measurement value may indicate that a significant degree of drying has proceeded and accordingly, a weight of an object to be dried is no longer reduced.

Also, the controller190may generate an event according to a determination that the second average measurement value is greater than the first average measurement value. A case in which the first average measurement value is greater than the second average measurement value may indicate that a weight of an object to be dried is reduced, which is determined that drying is not yet completed but proceeding. The remaining cases except for the case may be determined to be cases in which drying has been completed. In the current embodiment of the disclosure, a case in which the second average measurement value is greater than the first average measurement value may be also included in event generation conditions by considering that noise may be generated by a rotation of the drum120and an external factor.

Meanwhile, after an event is generated, the controller190may further perform a comparison with an average measurement value (or a measurement value) sequentially calculated, in operation507, and generate an event based on a result of the comparison, in operation509. For example, the controller190may compare the second average measurement value with a third average measurement value calculated after the second average measurement value is calculated, and generate an event according to a determination that the third average measurement value is greater than or equal to the second average measurement value, in operations507and509. Upon satisfaction of the above-described conditions, two events may be accumulated in operations506and509. Operations505to510may be repeatedly performed. The above description relates to an event generation condition based on average measurement values, however, the operations505to510may also be applied to measurement values, not average measurement values.

According to an embodiment of the disclosure, the controller190may obtain a measurement value and/or an average measurement value of motor current periodically, and whenever the controller190obtains a measurement value and/or an average measurement value of motor current, the controller190may generate an event according to a determination that the measurement value and/or the average measurement value of the motor current is greater than or equal to a preset magnitude. A plurality of events may be sequentially generated in a case in which a load of the washing machine100converges to a certain range. Accordingly, based on a determination that the number of events sequentially generated is more than or equal to a preset number, the controller190may finish the drying operation.

The controller190may compare sequentially obtained average measurement values with each other, and according to a determination that the average measurement value generated later is smaller than the average measurement value generated earlier, the controller190may erase at least one event already generated, thereby performing initialization, in operation509. For example, in a case in which the second average measurement value is smaller than the first average measurement value, it may be determined that a load of the object to be dried is reduced, which represents a continuous reduction of water. That is, the case may correspond to a state in which drying has been not yet completed, which requires an additional drying time.

Meanwhile, the controller190may repeatedly perform operations505to510, thereby accumulating a plurality of events. The accumulated events may have been sequentially generated.

The controller190may finish the drying operation based on the number of the generated events, in operation511. That is, the controller190may control the hot air supplier212based on the number of events. The controller190may compare the number of events with the preset number, in operation510, and according to a determination that the number of events sequentially generated is more than or equal to the preset number, the controller190may finish the drying operation, in operation511, wherein the preset number may be 5, however, the preset number may be set to various values depending on a weight of laundry and/or a kind of laundry. For example, the preset number may be set to 7 that is greater than 5, with respect to heavy laundry from which a large amount of water needs to be removed. Also, the preset number may be set to 7 that is greater than 5, with respect to laundry made of cotton fiber not synthetic fiber, because speed at which water is removed from the cotton fiber is slower than speed at which water is removed from the synthetic fiber. In contrast, the preset number may be set to 3 that is smaller than 5, with respect to laundry made of a relatively light material or synthetic fiber.

Meanwhile, as described above, the disclosure may determine a dried state based on the number of events based on motor current. To raise reliability on the determination, the disclosure may determine a dried state by further considering a temperature difference of the dryer200, in addition to events. The operation will be described in detail with reference toFIGS.8and9.

FIG.8is a flowchart illustrating a method for controlling a washing machine including a dryer according to an embodiment of the disclosure, andFIG.9shows differences between inlet temperature and outlet temperature of the dryer according to an embodiment of the disclosure shown inFIG.8.

A determination on whether a condition according to the current embodiment of the disclosure is satisfied may be conducted independently from a determination on whether the condition described above with reference toFIG.5is satisfied. However, both a determination on whether the condition according to the current embodiment of the disclosure is satisfied and a determination on whether the condition described above with reference toFIG.5is satisfied may be conducted. In this case, in a case in which both the conditions are satisfied, it may be determined that a drying operation has been completed.

The controller190may operate the dryer200, in operation801. During a drying operation, the washing machine100may operate the dryer200to apply hot air to laundry accommodated in the drum120to thereby evaporate water contained in the laundry.

The dryer200according to an embodiment of the disclosure may include the first temperature sensor174and the second temperature sensor175. The controller190may obtain first temperature from the first temperature sensor174, in operation802, and obtain second temperature from the second temperature sensor175, in operation803. The first temperature sensor174may be positioned at a location at which air enters the dryer200, and the second temperature sensor175may be positioned at a location at which air is discharged from the dryer200.

Air entering the dryer200among air circulating through the drum120and the dryer200may be at relatively low temperature because the air has lost heat by water contained in laundry accommodated in the drum120, and air discharged from the dryer200may be at relatively high temperature because the air has been heated by the duct heater215(seeFIG.4). A difference between temperature measured by the second temperature sensor175and temperature measured by the first temperature174may be reduced according to the progress of the drying operation.

According to an embodiment of the disclosure, upon generation of an event, the controller190may control the hot air supplier212based on a difference between the first temperature measured by the first temperature sensor174and the second temperature measured by the second temperature sensor175. Generation of an event may represent that drying has been substantially performed, and satisfaction of the condition related to a temperature difference, as an additional condition, may be considered as completion of drying. In this case, the controller190may finish the drying operation by controlling the hot air supplier212.

It is seen fromFIG.9that a difference between temperature of entering air and temperature of discharging air is reduced according to the progress of a drying operation. Also, the temperature difference may be reduced more rapidly with respect to a lighter weight of laundry. However, the temperature difference may have a constant difference value upon completion of a drying operation, regardless of a weight. For example, upon completion of drying, the temperature difference may be about 10° C.

According to a determination that the difference between the first temperature measured by the first temperature sensor174and the second temperature measured by the second temperature sensor175is smaller than or equal to a preset temperature difference, in operation804, the controller190may finish the drying operation, in operation805.

According to an embodiment of the disclosure, the controller190may finish the drying operation according to a determination that the difference between the first temperature measured by the first temperature sensor174and the second temperature measured by the second temperature sensor175is smaller than or equal to the preset temperature difference, regardless of other conditions.

Also, in an embodiment of the disclosure, according to a determination that the number of sequentially accumulated events is more than or equal to a preset number (seeFIG.5) and a difference between temperature measured by the first temperature sensor174and temperature measured by the second temperature sensor175is smaller than or equal to the preset temperature difference, the controller190may finish the drying operation. Also, according to an embodiment of the disclosure, the controller190may control the hot air supplier212based on a result obtained by comparing the difference between the first temperature and the second temperature with a preset reference value.

Meanwhile, an additional condition for finishing a drying operation has been described with reference toFIGS.8and9. The above-mentioned temperature difference may be a condition for finishing a dying operation, however, another difference value may be used to change a condition for finishing a drying operation or as criterion for a time at which a dried state is determined. The operation will be described in detail with reference toFIGS.10and11.

FIG.10is a flowchart illustrating a method for controlling a washing machine according to an embodiment of the disclosure to reduce a number of events.

The controller190may operate the dryer200, in operation1001. During a drying operation, the washing machine100may operate the dryer200to apply hot air to laundry accommodated inside the drum120to thereby evaporate water contained in the laundry.

The controller190may obtain first temperature from the first temperature sensor174, in operation1002, and obtain second temperature from the second temperature sensor175, in operation1003.

Then, the controller190may finish the drying operation according to a determination that a difference between the first temperature measured by the first temperature sensor174and the second temperature measured by the second temperature sensor175is smaller than or equal to a first temperature difference, in operation1005. The first temperature difference may be the preset temperature difference applied to the embodiment ofFIG.8, and may be about 10° C. which is criterion for finishing a drying operation.

Meanwhile, the controller190may determine that the drying operation needs to continue to be performed, according to a determination that a difference between the first temperature measured by the first temperature sensor174and the second temperature measured by the second temperature sensor175is greater than the first temperature difference. Then, the controller190may determine whether the difference is smaller than or equal to a second temperature difference, in operation1006. The second temperature difference may be close to the first temperature difference although the second temperature difference is greater than the first temperature difference, and the second temperature difference may represent an approach to completion of a drying operation.

According to a determination that the difference between the first temperature measured by the first temperature sensor174and the second temperature measured by the second temperature sensor175is smaller than or equal to the first temperature difference, the controller190may reduce a preset number of events, in operation1007. The current embodiment of the disclosure may be considered together with the embodiment ofFIG.5, and may be applied to operation510ofFIG.5. According to a determination that a difference between temperature measured by the first temperature sensor174and temperature measured by the second temperature sensor175is smaller than or equal to a certain difference, an approach to completion of a drying operation may be determined, and by reducing the number of events, a condition for drying completion may be loosened.

So far, an embodiment for changing a condition for finishing a drying operation has been described with reference toFIG.10. Hereinafter, an embodiment for determining a time at which a dried state is determined will be described in detail with reference toFIG.11.

FIG.11is a flowchart illustrating a method for controlling a washing machine according to an embodiment of the disclosure to determine an event generation time.

Meanwhile, in the embodiment of the disclosure described above with reference toFIG.5, obtaining a measurement value of motor current or generating an event may be performed until a drying operation is finished after the drying operation starts. However, obtaining a measurement value of motor current or generating an event throughout a drying operation may cause unnecessary power consumption by the current sensor173.

The controller190may operate the dryer200, in operation1101. During a drying operation, the washing machine100may operate the dryer200to apply hot air to laundry accommodated inside the drum120to thereby evaporate water contained in the laundry.

The controller190may obtain first temperature from the first temperature sensor174, in operation1102, and obtain second temperature from the second temperature sensor175, in operation1103.

According to a determination that a difference between the first temperature measured by the first temperature sensor174and the second temperature measured by the second temperature sensor175is smaller than or equal to a third temperature difference, in operation1104, the controller190may obtain a measurement value and/or an average measurement value of motor current, at regular time intervals, or generate an event, in operation1105. That is, a condition for performing operation503or506in the method illustrated inFIG.5may be applied. The third temperature difference may be close to the second temperature difference ofFIG.10although the third temperature difference is greater than the second temperature difference, and the third temperature difference may represent a certain degree of progress toward completion of a drying operation even though the third temperature difference does not represent an approach to completion of a drying operation.

FIG.12is a flowchart illustrating a method for controlling a washing machine according to an embodiment of the disclosure to determine a completion time of a dry operation based on an initial load.

The current embodiment of the disclosure may consider an initial load of laundry upon putting the laundry, in addition to the conditions related to an event and a temperature difference of the dryer200, among the above-described conditions for finishing a drying operation. A difference between a weight of laundry containing no water before washing and a weight of the laundry containing little water after a drying operation may be small. Under an assumption that the drum120accommodating laundry rotates at the same rpm both before a washing operation and after a drying operation, the same or similar magnitude of motor current may be applied to the drum motor130due to the same load of the laundry. Based on the property, the condition related to an event, and the condition related to a temperature difference, a dried state may be more accurately determined.

The controller190may rotate the drum120at preset rpm before starting a washing operation, in operation1201. For example, the controller190may control, before water is supplied to laundry, that is, before a washing operation starts, the motor driving circuit180to rotate the drum120at low rpm (for example, rpm between about 45 rpm to about 60 rpm).

The controller190may obtain a first magnitude value of motor current, in operation1202. Through the process, the controller190may estimate a weight of laundry. As a result, the controller190may obtain a magnitude value of motor current that is applied for constant rpm before water is supplied to laundry.

The controller190may rotate the drum120at preset rpm during a drying operation, in operation1203. The preset rpm may be the same rpm as in operation1201. The controller190may consider a magnitude of motor current applied under a condition of the same rpm, to compare a weight of the laundry immediately after the laundry is put with a weight of the laundry after the laundry is dried.

The controller190may obtain a second magnitude value of motor current, in operation1204. Through the process, the controller190may estimate a weight of the laundry during the drying operation, or determine a degree of progress of the drying operation.

According to the current embodiment of the disclosure, additionally, individual operation times of the washing machine1may be determined based on a current signal depending on motor current. According to an embodiment of the disclosure, the controller190may determine an execution time of a washing operation based on a current signal. That is, the controller190may determine a time of a washing operation by considering a weight of laundry. Also, according to an embodiment of the disclosure, the controller190may determine an amount of water to be supplied to the tub110, based on a current signal, and control the water supplier140according to the amount of water.

The controller190may determine whether a difference between the first magnitude value and the second magnitude value is smaller than or equal to a preset current difference, in operation1205. According to a determination that the difference between the first magnitude value and the second magnitude is smaller than or equal to the preset current difference, the controller190may immediately finish the drying operation.

However, to secure reliability of a determination on a dried state, the controller190may further determine whether the following additional condition is satisfied.

The controller190may finish the drying operation according to a determination that the number of sequentially generated events is more than or equal to a preset number, in operation1208.

In an embodiment of the disclosure, according to a determination that the difference between the first magnitude value and the second magnitude value is smaller than or equal to the preset current difference and the number of sequentially generated events is more than or equal to the preset number, the controller190may finish the drying operation.

In contrast, according to a determination that the difference between the first magnitude value and the second magnitude value is greater than the preset current difference, the controller190may maintain the drying operation, in operation1209.

Also, the controller190may finish the drying operation according to a determination that a difference between temperature measured by the first temperature sensor174and temperature measured by the second temperature sensor175is smaller than or equal to a first temperature difference.

In an embodiment of the disclosure, according to a determination that the difference between the first magnitude value and the second magnitude value is smaller than or equal to the preset current difference and the difference between the temperature measured by the first temperature sensor174and the temperature measured by the second temperature sensor175is smaller than or equal to the first temperature difference, the controller190may finish the drying operation.

In contrast, the controller190may maintain the drying operation according to a determination that the difference between the temperature measured by the first temperature sensor174and the temperature measured by the second temperature sensor175is greater than the first temperature difference, in operation1209.

FIG.13is a flowchart illustrating a cooling operation of a washing machine according to an embodiment of the disclosure.

The washing machine100according to an embodiment of the disclosure may perform a cooling operation for a preset time period from a time at which a drying operation is finished or after a drying operation is finished. The cooling operation may be an operation for removing heat remaining in laundry by turning off the heater and operating the fan213. The cooling operation may prevent a user from being exposed to hot air excessively discharged from the door102opened after a drying operation is finished.

To perform the cooling operation, the controller190may turn off the heater, in operation1301, and operate the fan213, in operation1302. At this time, the fan213may be repeatedly turned on/off in a turned-off state of the heater. For example, the fan213may be set to be turned on for 20 seconds and then turned off for 10 seconds.

After the fan213operates for a preset time period, the cooling operation may terminate, in operation1303.

According to an aspect of the disclosure, by using the non-contact sensors already included in the washing machine, a dried state may be accurately determined.

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

The computer-readable recording medium may include all kinds of recording media storing instructions that can be interpreted by a computer. For example, the computer-readable recording medium may be Read Only Memory (ROM), Random Access Memory (RAM), a magnetic tape, a magnetic disc, flash memory, an optical data storage device, etc.

The machine-readable storage medium may be provided in the form of a non-transitory storage medium, wherein the term ‘non-transitory’ simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium. For example, a ‘non-transitory storage medium’ may include a buffer in which data is temporarily stored.

So far, the disclosed embodiments have been described with reference to the accompanying drawings. It will be apparent that those skilled in the art can make various modifications thereto without changing the technical spirit and essential features of the present disclosure. Thus, it should be understood that the embodiments described above are merely for illustrative purposes and not for limitation purposes in all aspects.