Patent Description:
In general, a laundry treating apparatus may include a washing machine, a dryer, a device for refreshing clothes, and the like. The washing machine may be a washing machine having a drying function.

In a washing machine, a drum accommodating laundry is rotatably provided in a tub that provides a space for storing water. Through holes are formed in such a drum, so that water in the tub flows into the drum. In this state, when the drum is rotated, the laundry in the drum flows and contamination of the laundry is removed.

Such a washing machine is also provided with a heater for heating the water in the tub. The heater is operated in a state of being submerged in water in the tub, so it is common to directly heat the water. However, since this type of heater must always be operated in a state of being submerged in water at all times for safety reasons, it can be used for heating the water in the tub, but it is not suitable for heating the air in the drum in a state where there is no water in the tub, or for heating wet laundry before spin-drying.

Recently, a washing machine in which a drum is heated by an induction heating system has been used. Such a washing machine may be configured to have a heat sensor disposed between the drum and a tank (or tub) to detect the temperature of water or air in the tank.

In the above mentioned scheme, the temperature of the drum is inevitably estimated based on the temperature of water or air. Meanwhile, the temperature of the drum is sensitively fluctuated according to the output of an induction heating system, but the temperature of water or air is slowly fluctuated. Therefore, the value detected by a heat sensor may not accurately reflect the temperature fluctuation of the drum.

Meanwhile, US Patent Application Publication No. <CIT> discloses a method of estimating a temperature by using a characteristic change of drum according to a temperature, in particular, by using an inductance change.

<FIG> shows a resonant circuit for using such a method. Referring to <FIG>, the driving of a power device Q1 is turned off near a zero crossing of system voltage by using a resonance circuit <NUM>, and at this time, resonance frequency (fres) can be measured by using an autonomous resonant voltage.

An inductance Leq can be derived by using the measured resonant frequency (fres) and using a relational expression ( <MAT>) for resonant frequency, inductance, and capacitance.

Here, as the temperature increases, the relative magnetic permeability increases and the inductance (Leq) also increases. Accordingly, the temperature of a drum <NUM> (load) can be estimated through the change in inductance (Leq) according to the temperature change.

<FIG> shows a voltage waveform when measuring a resonance frequency, and <FIG> shows an enlarged view of a portion A of <FIG>.

Referring to <FIG>, it can be seen that the resonance frequency (fres) changes by about <NUM>% when the load temperature changes by <NUM>. That is, it can be seen that the fluctuation of the resonance frequency (fres) according to the temperature change is too small to estimate the temperature by using the resonance frequency.

That is, referring to <FIG>, it can be seen that a portion of waveform W after a circuit is turned off is too small to measure the fluctuation.

In addition, the change in inductance (Leq) fluctuates by <NUM>%/°C. That is, it can fluctuate by <NUM>% depending on the temperature. In addition, the capacitance (Ceq) in the resonant frequency (fres) calculation formula should be less than or equal to <NUM>% depending on a dispersion of components and a fluctuation dispersion according to a temperature.

<FIG> is a graph illustrating a relationship between a temperature and a resonance frequency when estimating a temperature by using a resonance frequency.

Due to the circumstances described above, when a temperature is estimated by using a resonant frequency, an error of the estimated temperature may occur by about ±<NUM> or more. However, in order to be applied to general washing machine products, accuracy within ±<NUM> is required.

In addition, there is a problem in that a power of circuit must be turned off for a certain time in order to measure the resonance frequency (fres).

Therefore, an improvement or new method for accurately estimating the temperature of drum by solving these problems is required.

A further example of the prior art is disclosed in the patent application published under the following number: <CIT>.

An object of the present invention is to solve the above and other problems.

Another object of the present invention is to provide a laundry treating apparatus, such as a dryer which can accurately estimate a temperature of a drum, a washing machine, a washing machine-and-dryer, and an apparatus for refreshing clothes.

Another object is to provide a laundry treating apparatus capable of heating a drum by an induction heater and accurately estimating the temperature of the drum.

Another object of the present invention is to provide a laundry treating apparatus capable of accurately estimating the temperature of the drum by minimizing the influence of a magnetic field generated by the induction heater.

Another object of the present invention is to provide a laundry treating apparatus capable of accurately estimating the temperature of the drum regardless of a distance between a load (drum) and a tub.

Another object of the present invention is to provide a laundry treating apparatus capable of estimating the temperature of a rotating load (drum).

Another object of the present invention is to provide a laundry treating apparatus capable of continuously estimating a temperature without turning off a power device to estimate a temperature.

Another object of the present invention is to provide a laundry treating apparatus that minimizes vibration due to unbalance, even when a drum having a device for estimating a temperature rotates at a high speed.

In order to achieve the above object, there is provided a laundry treating apparatus according to an aspect of the present invention, including: a first circuit including a first coil and a second circuit including a second coil and a thermistor.

The resistance of the thermistor changes according to temperature, and the current value of the second coil changes according to the change in resistance of the thermistor. The resistance of the thermistor may change according to the temperature of a drum.

The thermistor may include an NTC thermistor whose resistance decreases when the temperature increases. The resistance of the NTC thermistor may decrease when the ambient temperature increases. The resistance of the NTC thermistor may decrease when the temperature of the drum increases.

The thermistor may include a PTC thermistor whose resistance increases when the temperature increases. The resistance of the PTC thermistor may increase as the ambient temperature increases. The resistance of the PTC thermistor may increase when the temperature of the drum increases.

The second circuit may be provided to be movable with respect to the first circuit. The second circuit may be provided to be movable with respect to the first coil.

The laundry treating apparatus includes a drum. The drum may be rotatably provided.

The laundry treating apparatus may further include a tub accommodating the drum.

The drum may be rotatably provided in the tub.

The laundry treating apparatus may include a cabinet. The cabinet may form an outer shape of the laundry treating apparatus. The cabinet may accommodate the tub.

The first coil may be installed in the tub. The first circuit may be installed in the tub.

The first coil may be installed inside the cabinet. The first circuit may be installed in the cabinet.

The second circuit is disposed in the drum.

The second coil may be disposed at a position overlapping the first coil in the length direction of the rotation central shaft of the drum.

The second coil may be installed in a position passing the shortest distance from the first coil according to the rotation of the drum. The second coil may be installed in a position where a straight line which passes the first coil and is perpendicular to the rotation center line of the drum meets the drum.

The second circuit may be installed on the outer surface of the drum.

The laundry treating apparatus may include a lifter provided on an inner surface of the drum.

The second circuit may be installed at a position corresponding to the lifter.

The second circuit may be installed at a position corresponding to the lifter on the outer surface of the drum.

The second circuit may be installed on an outer surface of a portion of the drum where the lifter is disposed.

The second circuit may be installed on the inner surface of the drum in a portion of the drum where the lifter is disposed.

The drum may include a body having an extended cylindrical shape and a through hole formed in the body.

The laundry treating apparatus may include a non-magnetic balance maintaining unit. The balance maintaining unit may be provided in the drum. The balance maintaining unit may be provided in the lifter. The balance maintaining unit may be provided in the lifter.

The second circuit and the balance maintaining unit may be arranged at regular intervals along a circumferential direction of the drum.

The balance maintaining unit may include one or more balance maintaining units. The second circuit and the one or more balance maintaining units may be arranged at regular intervals.

The lifter may include a plurality of lifters arranged at regular intervals along the circumferential direction of the drum.

The lifter may include a plurality of lifters. The plurality of lifters may be arranged at regular intervals along the circumferential direction of the drum.

The second circuit may be installed at a position corresponding to any one of the plurality of lifters.

The second circuit may be installed on an outer surface of a portion of the drum in which the any one lifter is disposed.

The balance maintaining unit may be provided at a position corresponding to remaining lifters among the plurality of lifters. The balance maintaining unit may be provided inside the remaining lifters.

The laundry treating apparatus includes an induction heater that heats the drum. The induction heater may generate a magnetic field. The induction heater heats the drum by using a magnetic field.

The induction heater may be spaced apart from the drum. The induction heater may be installed in the tub. The induction heater may be fixed to the tub.

The induction heater may be disposed inside the case or on an inner wall. In a laundry treating apparatus such as a dryer having no tub, it may be disposed inside a case or on an inner wall.

The first coil may be installed in an opposite side of the induction heater. The first coil may be installed in the opposite side of the induction heater with respect to the center of the tub. The first coil may be installed in the opposite side of the induction heater with respect to the center of the drum.

The first coil may be installed within a range of ±<NUM> degrees from an opposite point of the induction heater with respect to the center of the tub.

The induction heater may be disposed at a position spaced apart from the drum at an upper side, a lower side, or a right side of the drum inside the case, in a laundry treating apparatus having no tub such as a dryer. In this case, the first circuit including the first coil may be positioned opposite to the induction heater. Alternatively, it may be fixed to be spaced apart from the drum at a position spaced apart by a certain distance with respect to the drum rotation direction.

A size of the first coil may be greater than a size of the second coil. The first coil may occupy a larger area than the area occupied by the second coil along the circumferential direction of the drum.

The laundry treating apparatus may include a power supply unit for applying power to the first coil.

The power supply unit may apply AC power to the first coil. The power supply unit may apply a resonant frequency.

The first circuit may include a capacitor. The capacitor may be connected in parallel with the first coil.

The laundry treating apparatus may include a controller.

The controller may be connected to the first circuit. The controller may estimate the temperature of the drum.

The controller may estimate the temperature of the drum based on a resistance value of the thermistor.

The laundry treating apparatus may include a current detection unit. The current detection unit may be connected in series with the first coil. The current detection unit may be connected in series with the power supply unit.

The laundry treating apparatus may include a voltage detection unit. The voltage detection unit may be connected in parallel with the first coil. The voltage detection unit may be connected in parallel with the power supply unit.

The controller may estimate the temperature of the drum based on the measured impedance. The measured impedance may be defined as a value obtained by dividing a voltage value detected by the voltage detection unit by a current value detected by the current detection unit.

The controller may compensate an error based on the measured impedance and the equivalent impedance of the first and second circuits. The equivalent impedance of the first and second circuits may be an equivalent impedance at a resonant frequency.

The power supply may change an apply frequency, when the resonance frequency of the measured impedance is different from the resonance frequency of the equivalent impedance.

When the phase angle of the measured impedance is different from the phase angle of the equivalent impedance, the controller may compensate the error of phase angle by using the rotation angle of the drum.

According to an aspect of the present invention, the temperature of the load (drum) of the rotating induction heater may be estimated by using the NTC.

That is, a sensing coil (first coil) and a capacitor are configured in parallel to form a primary side (first circuit), and a secondary side (second circuit) is configured by an NTC and a second coil, and then the temperature of the drum can be estimated by using the voltage/current value of the NTC detected by the first coil.

At this time, the primary side (first circuit) may be attached in the opposite direction to the heater coil to minimize the magnetic effect with the induction heater coil, and the secondary side (second circuit) may be attached closely to the outer surface of one of three lifters located inside the load (drum).

To balance the high-speed rotating load (drum), a non-magnetic material that can balance the weight of the load (drum) can be attached inside or outside the remaining two lifters.

Therefore, the phase, frequency, and magnitude of the equivalent impedance Zeq may be derived by using the voltage and current values sensed from the primary side, and the Rntc value of the NTC and the temperature of the load (drum) may be estimated by using the derived value.

As a specific example for this, an embodiment of the present invention provides a laundry treating apparatus including a cabinet; a drum which is rotatably provided in the cabinet and accommodates a treating target (e.g. clothes); an induction heater which is spaced apart from the drum and disposed inside or on an inner wall of the cabinet to heat the drum; a first circuit which is disposed at a position spaced apart from the induction heater inside the cabinet or on an inner wall and includes a first coil; and a second circuit including a second coil which is disposed in the drum and disposed at a point in the drum area overlapping the first coil in a rotational direction of the drum when the drum rotates and a thermal variable resistance unit whose resistance changes according to the temperature of the drum.

A laundry treating apparatus according to another embodiment of the present invention includes: a tub; a drum which is rotatably provided in the tub and accommodates an object; an induction heater which is fixed to the tub while being spaced apart from the drum, and heats the drum; a first circuit which is installed in the tub and includes a first coil; and a second circuit having a second coil which is installed in the drum and positioned to pass a point within an area of the drum overlapping with the first coil to interact within the circumferential direction range of the drum upon rotation of the drum and a thermal variable resistance unit that transmits to the second coil at least one value of voltage and current values according to the temperature of the drum.

Another embodiment of the present invention may include a controller which is connected to the first circuit, and estimates the temperature of the drum by using the at least one value of voltage and current values according to the temperature of the drum received due to the interaction between the second coil and the first coil.

In addition, the first circuit may further include a capacitor connected in parallel with the first coil.

In addition, the laundry treating apparatus may include: a power supply unit; a current detection unit connected in series with the first coil; and a voltage detection unit connected in parallel with the first coil.

In addition, the power supply unit may apply a resonant frequency.

In addition, the capacitor may be for increasing the resolution of the value related to the temperature of the drum received through the second coil.

In addition, the detection unit may be an NTC that outputs a resistance value that changes according to a temperature as a voltage value.

In addition, the size of the first coil may be larger than the size of the second coil.

In addition, the first coil may be installed in the opposite side of the induction heater in the tub.

In addition, the first coil may be installed in a range of ±<NUM> degrees from the opposite side of the induction heater in the tub.

In addition, the second coil may be installed at a position passing the shortest distance from the first coil according to the rotation of the drum.

In addition, the second circuit may be installed on the outer surface of the drum.

In addition, the laundry treating apparatus may further include a balance maintaining unit installed at a position equalizing an angle with respect to a position where the second circuit of the drum is attached.

In addition, the controller may estimate the resistance value of the NTC and the temperature of the drum by comparing an impedance obtained by detecting the voltage and current values received from the second coil due to the interaction of the first coil and an equivalent impedance of the first and second circuits.

According to another embodiment of the present invention, a method of controlling a laundry treating apparatus including: a tub; a drum which is rotatably provided in the tub and accommodates an object; an induction heater which is fixed to the tub while being spaced apart from the drum, and heats the drum; a first circuit which is installed in the tub and includes a first coil; and a second circuit having a second coil which is installed in the drum and positioned to pass a point within an area of the drum overlapping with the first coil to interact within the circumferential direction range of the drum upon rotation of the drum and a detection unit that transmits to the second coil at least one value of voltage and current values according to the temperature of the drum, the method including: driving the laundry treating apparatus; detecting an output value of the detection unit through the first circuit; calculating an equivalent impedance of the first circuit; matching the impedance measured by an output value of the detection unit with a resonance frequency of the equivalent impedance; matching the impedance measured by the output value of the detection unit and the phase angle of the equivalent impedance; and estimating the temperature of the drum through the detection unit based on the magnitude of the equivalent impedance.

The matching of the resonance frequency may include: obtaining an error by comparing an impedance measured by an output value of the detection unit with a resonance frequency of the equivalent impedance; and compensating an error in the inductance value of the first coil.

The matching of the phase angles may include: obtaining an error by comparing the impedance measured by the output value of the detection unit with the phase angle of the equivalent impedance; and compensating the error in the phase angle by using the rotation angle of the drum.

The driving of the laundry treating apparatus may include heating and rotating the drum; and applying a voltage of a resonant frequency to the first circuit.

In addition, the driving of the laundry treating apparatus may include the first coil and arranging the first coil.

According to another embodiment of the present invention, a laundry treating apparatus includes a fixing part such as a cabinet and a rotating part rotating with respect to the fixing part, wherein a first circuit including a first coil is disposed in the fixing part, and the rotating part includes a second circuit including a second coil disposed at a position corresponding to the first coil and a thermal variable resistance unit which is electrically connected to the second coil and has a flowing current value or voltage value which is changed as the internal resistance is changed according to the temperature of the rotating part, wherein the temperature of the rotating part is determined by the current value or voltage value of the first coil corresponding to the current value or voltage value of the second coil.

The fixing part may be an inner wall of the cabinet or any position inside the cabinet, and may be a tub which is disposed inside the cabinet to accommodate the rotating part.

In a dryer or laundry treating apparatus having no tub, the first circuit may be disposed on an inner wall of the cabinet at a lower portion or a side surface of the rotating part.

The rotating part includes a drum disposed to rotate inside the cabinet or the tub. The second circuit may be disposed in the drum, and may be disposed on an outer surface or an inner surface of the drum.

The laundry treating apparatus may include a lifter disposed inside the drum, and the second circuit may be disposed in a drum area corresponding to the lifter. The second circuit may be disposed on an outer surface of the drum corresponding to the lifter or an inner surface of the drum in which the lifter is mounted.

The first coil and the second coil are disposed to overlap each other with respect to the drum rotation direction. The thermal variable resistance unit of the second circuit may be disposed in a drum area corresponding to the lifter or a drum area corresponding to the induction heater.

The first coil may be configured to be larger than or equal to the second coil. For example, the first coil may be configured to be larger than the second coil. Even if the first coil and the second coil have the same size, the number of turns of the first coil may be larger than the number of turns of the second coil.

A distance between the first coil and the second coil may be <NUM> to <NUM>.

The drum temperature may be estimated through the magnitude of the impedance at a specified frequency, when a frequency is specified between the first coil and the second coil.

The first coil may be disposed at a position opposite to the induction heater based on the drum rotation shaft, and may be disposed at a position within <NUM> degrees in both directions from a position opposite by <NUM> degrees to the induction heater.

The rotating part may dispose a balance weight at a position spaced apart from the second coil, and a laundry treating apparatus having a rotating part rotating at a low speed, such as a dryer, may not include the balance weight.

According to at least one of embodiments of the present invention, the temperature of a drum may be estimated by using the characteristics of a thermistor whose resistance changes according to a temperature.

According to at least one of embodiments of the present invention, the temperature may be estimated irrespective of a distance that is structurally generated due to a drum and a tub.

According to at least one of embodiments of the present invention, the temperature may be estimated even under a condition in which a load (drum) rotates.

In addition, the influence of an inductance/capacitance distribution on the temperature estimation can be reduced by including an NTC thermistor.

In addition, continuous temperature estimation can be performed without turning off a power device to estimate a temperature. Accordingly, the performance of laundry treating apparatus can be improved.

Description will now be given in detail according to exemplary embodiments disclosed herein, with reference to the accompanying drawings. For the sake of brief description with reference to the drawings, the same or equivalent components may be denoted by the same reference numbers, and description thereof will not be repeated.

In general, suffixes such as "module" and "unit" may be used to refer to elements or components. Use of such suffixes herein is merely intended to facilitate description of the specification, and the suffixes do not have any special meaning or function.

In the present invention, that which is well known to one of ordinary skill in the relevant art has generally been omitted for the sake of brevity. The accompanying drawings are used to assist in easy understanding of various technical features and it should be understood that the embodiments presented herein are not limited by the accompanying drawings.

It will be understood that when an element is referred to as being "connected with" another element, there may be intervening elements present. In contrast, it will be understood that when an element is referred to as being "directly connected with" another element, there are no intervening elements present.

In addition, when an element such as a layer, an area, or a module is referred to as existing "on" another element, it can be appreciated that it directly exists on other element or an intervening element may exist therebetween.

A singular representation may include a plural representation unless context clearly indicates otherwise.

A laundry treating apparatus of the present invention may correspond to a washing machine, a dryer, and a washing machine integrated with a dryer (a dryer-integrated washing machine). Hereinafter, as a laundry treating apparatus of the present invention, a washing machine will be described as a representative example. However, the laundry treating apparatus of the present invention is not limited thereto.

Hereinafter, a laundry treating apparatus according to an embodiment of the present invention will be described with reference to <FIG>.

<FIG> is a perspective view illustrating an exterior of a washing machine according to an embodiment of the present invention. <FIG> is a cross-sectional view illustrating an interior of a washing machine according to an embodiment of the present invention. <FIG> is a conceptual diagram in which a separate type induction heater module is mounted on a tub.

A washing machine according to an embodiment of the present invention may include a tub <NUM> and a drum <NUM>. The washing machine may further include a cabinet <NUM> forming an outer shape. The washing machine may further include an induction heater <NUM> provided to heat the drum <NUM>.

The tub <NUM> may be provided inside the cabinet <NUM>. The tub <NUM> may provide an accommodation space. The tub <NUM> may have an opening in a forward direction. The tub <NUM> may accommodate washing water. The tub <NUM> may be provided to accommodate the drum <NUM>.

The drum <NUM> may be rotatably provided inside the tub <NUM>. The drum <NUM> may be provided in the accommodation space of the tub <NUM>. The drum <NUM> may accommodate laundry. An opening may be provided in a forward direction of the drum <NUM>. Laundry may be loaded into the drum <NUM> through the opening.

A through hole <NUM> may be formed in the circumferential surface of the drum <NUM> so that air and washing water are communicated between the tub <NUM> and the drum <NUM>. Hereinafter, the circumferential surface of the drum <NUM> may also be referred to as a body of the drum <NUM>. The body of the drum <NUM> may extend in a cylindrical shape.

The drum <NUM> may be made of a conductor. The body of the drum <NUM> may be made of a conductor. The body of the drum <NUM> may be made of metal.

The induction heater or IH module <NUM> may heat the drum <NUM>. The induction heater <NUM> may generate a magnetic field. The induction heater <NUM> may be provided to heat the drum <NUM> by using a magnetic field.

The induction heater <NUM> may be provided on the outer circumferential surface of the tub <NUM>. The induction heater <NUM> may be provided in the upper portion of the tub <NUM>. The induction heater <NUM> may be fixed to the tub <NUM>. The induction heater <NUM> may be spaced apart from the drum <NUM>.

The tub <NUM> and the drum <NUM> may be formed in a cylindrical shape. The inner and outer circumferential surfaces of the tub <NUM> and the drum <NUM> may be formed in a substantially cylindrical shape.

Meanwhile, a laundry treating apparatus such as a dryer may not include a tub. The induction heater <NUM> may be provided in the cabinet. The induction heater <NUM> may be disposed inside the cabinet or on an inner wall. The induction heater <NUM> may be spaced apart from the drum <NUM> and fixed to the cabinet <NUM>.

<FIG> shows a washing machine in which the drum <NUM> is rotated based on a rotation shaft parallel to a ground. Unlike the drawing, the drum <NUM> and the tub <NUM> may have a tilting shape inclined in a rearward direction. The rotation shaft of the drum <NUM> may penetrate the rear surface of the washing machine. That is, a straight line extending from the rotation shaft <NUM> of a driving unit <NUM> may penetrate the rear surface of the washing machine.

The washing machine may further include a driving unit <NUM> provided to rotate the drum <NUM> inside the tub <NUM>. The driving unit <NUM> may include a motor <NUM>. The motor <NUM> may include a rotation shaft <NUM>. The rotation shaft <NUM> may be connected to the drum <NUM> to rotate the drum <NUM> inside the tub <NUM>.

The motor <NUM> may include a stator and a rotor. The rotor may be connected to the rotation shaft <NUM>.

The driving unit <NUM> may include a spider <NUM>. The spider <NUM> is a configuration that connects the drum <NUM> and the rotation shaft <NUM>, and may be a configuration for uniformly and stably transmitting the rotational force of the rotation shaft <NUM> to the drum <NUM>.

The spider <NUM> may be coupled to the drum <NUM> in such a manner that at least portion of the spider <NUM> is inserted into the rear wall of the drum <NUM>. To this end, the rear wall of the drum <NUM> may be formed in such a manner that it is recessed to the inside of the drum <NUM>. In addition, the spider <NUM> may be coupled to the drum <NUM> in such a manner that it is further inserted into the drum <NUM> at a portion of the center of rotation of the drum <NUM>.

A lifter <NUM> may be provided inside the drum <NUM>. A plurality of lifters <NUM> may be provided along the circumferential direction of the drum <NUM>. The lifter <NUM> may perform a function of agitating a laundry. For example, as the drum <NUM> rotates, the lifter <NUM> lifts a laundry to an upper portion.

The laundry moved to the upper portion is separated from the lifter <NUM> by gravity and falls to a lower portion. Washing may be performed by an impact force caused by the falling of such laundry. Agitation of laundry can enhance drying efficiency.

The lifter <NUM> may be formed by extending from a rear end of the drum <NUM> to a front end. Laundry may be evenly distributed back and forth inside the drum <NUM>.

The induction heater <NUM> is a device for heating the drum <NUM>.

As shown in <FIG>, the induction heater <NUM> may include a coil <NUM> that receives a current to generate a magnetic field. The coil <NUM> may generate an eddy current in the drum <NUM>.

The induction heater <NUM> may include a heater cover <NUM> accommodating the coil <NUM>. Hereinafter, a structure of the induction heater <NUM> and the principle of heating the drum <NUM> by the induction heater <NUM> will be omitted.

In the washing machine, the coil <NUM> heats the drum <NUM> to increase the temperature inside the drum <NUM> as well as the drum <NUM> itself. The induction heater <NUM> may heat the wash water in contact with the drum <NUM> through the heating of the drum <NUM>. The induction heater <NUM> may heat the laundry in contact with the inner circumferential surface of the drum <NUM>. The induction heater <NUM> may heat the laundry that is not in contact with the inner circumferential surface of the drum <NUM> by increasing the temperature inside the drum <NUM>.

The induction heater <NUM> may increase the washing effect by increasing the temperature of washing water, and laundry, and the ambient temperature inside the drum <NUM>. The induction heater <NUM> may dry a laundry by increasing the laundry, the drum <NUM> and the ambient temperature inside the drum <NUM>.

<FIG> shows that the induction heater <NUM> is provided in the upper side of the tub <NUM>, but it is not excluded that the induction heater <NUM> is provided on at least one surface of the upper side, lower side, and both sides of the tub <NUM>. The induction heater <NUM> may be installed at a position higher than the maximum water level of the wash water stored in the tub <NUM>.

The induction heater <NUM> may be provided in one side of the outer circumferential surface of the tub <NUM>, and the coil <NUM> may be provided to be wound at least once inside the cover <NUM> along a surface of the induction heater <NUM> adjacent to the tub <NUM>.

The induction heater <NUM> may generate an eddy current in the drum <NUM> by emitting an induced magnetic field directly to the outer circumferential surface of the drum <NUM>, and as a result, may directly heat the outer circumferential surface of the drum <NUM>.

The laundry treating apparatus according to an embodiment of the present invention may include a controller (not shown, it may have the same configuration as a controller <NUM> of <FIG>; hereinafter, it will be described using reference numeral <NUM>) for controlling an output of the induction heater <NUM>. The controller <NUM> may control an on/off and an output of the induction heater <NUM>.

The induction heater <NUM> may be connected to an external power supply source by an electric wire to receive power. Alternatively, the induction heater <NUM> may be connected to the controller <NUM> for controlling the operation of washing machine to receive power. The induction heater <NUM> may receive power from anywhere as long as it can supply power to the internal coil <NUM>.

When power is supplied to the induction heater <NUM> and AC current flows through the coil <NUM> provided in the induction heater <NUM>, the drum <NUM> is heated.

If power is supplied to the induction heater <NUM> and the drum <NUM> does not rotate, only a partial surface of the drum <NUM> is heated. Therefore, partial surface may be overheated and remaining surface of the drum <NUM> may not be heated or may be heated to a small degree. In addition, heat may not be smoothly supplied to the laundry accommodated in the drum <NUM>.

The controller <NUM> may rotate the drum <NUM> through the motor <NUM> of the driving unit <NUM> when the induction heater <NUM> is operated. The controller <NUM> may cause the induction heater <NUM> to operate when the drum <NUM> rotates.

If all surfaces of the outer circumferential surface of the drum <NUM> can face the induction heater <NUM>, the speed at which the motor <NUM> of the driving unit <NUM> rotates the drum <NUM> can safely be any speed.

Meanwhile, as the drum <NUM> rotates, all surfaces of the drum <NUM> may be heated, and the laundry inside the drum <NUM> may be evenly exposed to heat.

Accordingly, the laundry treating apparatus according to an embodiment of the present invention can evenly heat the outer circumferential surface of the drum <NUM>, even if the induction heater <NUM> is not installed in places such as the upper side, the lower side, both sides of the outer circumferential surface of the tub <NUM>, but is installed only in one place.

According to an embodiment of the present invention, the induction heater <NUM> can heat the drum <NUM> to a high temperature within a very short time. The induction heater <NUM> can heat the drum <NUM> to a target temperature within a very short time. The induction heater <NUM> can heat the drum <NUM> to <NUM> degrees Celsius or more within a very short time.

When the induction heater <NUM> is driven in a state where the drum <NUM> is stopped or is at a very slow rotation speed, a specific portion of the drum <NUM> may be overheated very quickly. When the induction heater <NUM> is driven in a state where the drum <NUM> is stopped or is at a very slow rotation speed, heat may not be sufficiently transmitted from the heated drum <NUM> to the laundry.

A correlation between the rotational speed of the drum <NUM> and the driving of the induction heater <NUM> may be very important. It may be more advantageous to rotate the drum <NUM> and drive the induction heater <NUM> than to drive the induction heater <NUM> and rotate the drum <NUM>.

<FIG> is a circuit diagram illustrating a circuit configuration of a washing machine according to an embodiment of the present invention. In addition, <FIG> is a schematic diagram illustrating an installation position of a circuit configuration of a washing machine according to an embodiment of the present invention.

Hereinafter, a circuit configuration of a laundry treating apparatus according to an embodiment of the present invention will be described in detail with reference to <FIG> and <FIG>.

The laundry treating apparatus according to an embodiment of the present invention may include a first circuit <NUM> which is installed in the tub <NUM> and includes a first coil <NUM>, a second coil <NUM> which is installed in the drum <NUM> and located to pass a point that interacts with the first coil <NUM> when the drum <NUM> rotates, and a second circuit <NUM> including a thermistor <NUM> whose resistance varies depending on temperature.

Like this, the second coil may be installed in the drum <NUM>, and may be located to pass a point within an area of the drum <NUM> overlapping to interact within a circumferential range of the first coil <NUM> and the drum <NUM> when the drum <NUM> rotates.

In addition, the washing machine according to an embodiment of the present invention may include a controller MCU <NUM> which is connected to the first circuit <NUM> and estimates a temperature of the drum <NUM> by using a value related to the temperature of the drum <NUM> received by the interaction between the second coil <NUM> and the first coil <NUM>.

Meanwhile, a laundry treating apparatus such as a dryer may not include a tub. The first circuit <NUM> may be disposed at a position capable of interacting with the second coil according to the rotational position of the drum on the inside or the inner wall of the cabinet <NUM>.

As shown in <FIG>, the first circuit <NUM> may further include a capacitor C connected in parallel with the first coil <NUM>.

The laundry treating apparatus may include a current detection unit <NUM> connected in series with the first coil <NUM> and a voltage detection unit <NUM> connected in parallel with the first coil <NUM>.

The thermistor <NUM> may be a Negative Temperature Coefficient-thermic resistor (NTC-thermistor) whose resistance decreases as the temperature increases. Hereinafter, the NTC-thermistor is also briefly referred to as an NTC.

The resistance value of the NTC may be referred to as Rntc. The NTC may have a resistance value Rntc that exponentially decreases according to the temperature of a load (drum). Hereinafter, the thermistor <NUM> and the NTC <NUM> will be described by using the same reference numeral.

As described above, the second circuit <NUM> installed in the drum <NUM> may output at least one (hereinafter, it will be expressed as a voltage value and/or a current value) of a voltage value and a current value according to a resistance value that decreases according to the temperature of the NTC <NUM>.

The output voltage value and/or current value of the NTC <NUM> may be transmitted to the second coil <NUM>. Thereafter, this value may be transmitted to the first circuit <NUM> by the interaction between the first coil <NUM> and the second coil <NUM>. That is, a current that fluctuates according to a change in the resistance value of the NTC <NUM> can be transmitted to the first coil <NUM> of the first circuit <NUM> by the interaction between the first coil <NUM> and the second coil <NUM>. In this case, the interaction may be an electromagnetic induction phenomenon in which current/voltage is induced between the first coil <NUM> and the second coil <NUM>.

The controller <NUM> may estimate a resistance value of the NTC <NUM> by using impedance obtained by detecting the voltage and current values obtained at this time. The controller <NUM> may estimate the temperature of the drum <NUM> from the estimated resistance value of the NTC <NUM>.

The controller <NUM> may compensate an error in the resistance value of the NTC <NUM> by comparing the impedance obtained by detecting the voltage and current values with an equivalent impedance of the first and second circuits <NUM> viewed from the capacitor. Through this, the error in the estimated temperature of the drum <NUM> can be compensated.

The process of estimating the temperature of the drum <NUM> will be described later in detail.

A power supply unit <NUM> of the first circuit <NUM> may apply a resonant frequency. This resonant frequency may be the same as the frequency of a signal induced to the primary coil <NUM> through the secondary coil <NUM>.

Impedance can be defined as a ratio of AC voltage and current which are generated in a reference point or applied to a specific object. An alternating signal, such as an AC voltage, has a phase. In order to compare the phases, it is necessary that the frequencies of two signals have the same state. This is because comparing of the phases may not be meaningful if the frequencies are different.

Therefore, in order to compare the measured impedance and the equivalent impedance, it may be necessary to compare the (resonant) frequency and then compare the phase angle.

Meanwhile, the capacitor C may increase the resolution (degree of change; degree of discrimination) of a value related to the temperature of the drum <NUM> received through the second coil <NUM>.

For example, in the case of a washing machine combined with dryer, a distance between the first coil <NUM> and the second coil <NUM> may occur due to a structural distance between the drum <NUM> and the tub <NUM>. The distance between the first coil <NUM> and the second coil <NUM> may be, for example, <NUM> to <NUM>. Accordingly, a mutual inductance M between the first coil <NUM> and the second coil <NUM> may be reduced.

Due to this, a change in the resistance value of the NTC <NUM> may not be significantly observed in the first circuit <NUM>. The capacitor C may compensate a phenomenon in which a change in the resistance value of the NTC <NUM> may not be significantly observed in the first circuit <NUM>.

Referring to <FIG>, the first coil <NUM> may be installed on the tub <NUM>, in the opposite side of the coil <NUM> of the induction heater <NUM>. In addition, the first coil <NUM> may be installed on the tub <NUM>, in a range of ±<NUM> degrees from the opposite side of the coil <NUM> of the induction heater <NUM>.

That is, in the case of a washing machine combined with dryer, the first coil <NUM> may be installed in the tub <NUM>. The first coil <NUM> may be located on the tub <NUM> in a direction opposite to the coil <NUM> of the induction heater <NUM>. Accordingly, the influence of the magnetic field generated in the coil <NUM> of the induction heater <NUM> on the first coil <NUM> may be minimized.

Meanwhile, the first coil <NUM> may be installed within a range between positions of adjacent lifters indicated by dotted line in <FIG>. That is, the first coil <NUM> may be installed on the tub <NUM> in a range within ±<NUM> degrees from the opposite side of the coil <NUM> of the induction heater <NUM>. Accordingly, the influence of the magnetic field generated in the coil <NUM> of the induction heater <NUM> on the first coil <NUM> may be minimized. Thus, interference of the first coil <NUM> with other structure that may be provided under the tub <NUM> such as a washing heater other than the induction heater <NUM> can be avoided.

The second coil <NUM> may be installed at a position passing the shortest distance from the first coil <NUM> according to the rotation of the drum <NUM>. That is, when the drum <NUM> rotates, the second coil <NUM> installed in the drum <NUM> may pass a position of the shortest distance from the first coil <NUM>.

In addition, the second circuit <NUM> including the second coil <NUM> may be installed on the outer surface of the drum <NUM>.

In the case of a washing machine combined with dryer, the second circuit <NUM> including the NTC <NUM> and the second coil <NUM> in the outside of the drum <NUM> can be installed at the lifter position of the drum <NUM> that is a load. Here, the dotted line in <FIG> indicates the position of the lifter.

When the second coil <NUM> is installed inside the drum <NUM>, current may not be transmitted to the first coil <NUM> side due to the material characteristics of the load (drum <NUM>).

Meanwhile, a balance maintaining unit <NUM> may be provided at a position that divides the circular angle of the drum <NUM> into equal parts with respect to a position where the second circuit <NUM> of the drum <NUM> is attached.

For example, in the case of a washing machine combined with dryer, it may be necessary to maintain the weight balance when rotating at high speed. Therefore, a weight balance may be achieved by attaching the balance maintaining unit <NUM> made of a material having non-magnetic properties.

In this case, for example, when the lifter is located at a position where the angle of the drum <NUM> is divided into three equal parts, and the second circuit <NUM> is provided in any one of three parts, such a balance maintaining unit <NUM> may be installed in the other two parts.

For example, in case of a dryer, it may not rotate at a high speed, the balance maintaining unit <NUM> for maintaining a weight balance may not be installed.

<FIG> is a schematic diagram illustrating an example of installation of a first coil and a second coil of a laundry treating apparatus according to an embodiment of the present invention.

Referring to <FIG>, the size of the first coil <NUM> may be greater than the size of the second coil <NUM>. That is, it may be advantageous that the size of the first coil <NUM> acting as a sensing coil is designed to be larger than the size of the second coil <NUM> transmitting a signal so as to maintain a constant inductance (L1, L2, M) value even during the rotation of the drum <NUM> in consideration of the rotation of the load (drum <NUM>).

In addition, depending on a distance between the applied washing machine and the first coil <NUM> and the second coil <NUM>, it may be necessary to optimize the number of turns of the first coil <NUM> and the value of the parallel capacitor C.

Meanwhile, the temperature error can be minimized by compensating an error by using rotation angle information of the drum <NUM>.

Hereinafter, a process of estimating the temperature of the drum <NUM> by using a circuit configuration of the washing machine according to an embodiment of the present invention shown in <FIG> will be described in detail.

Equation <NUM> is a calculation expression representing the equivalent impedance Zeq viewed from the first circuit <NUM> (first side). More specifically, Equation <NUM> is a calculation expression representing the equivalent impedance Zeq of the first and second circuits <NUM> and <NUM> viewed from the capacitor C. The explanation in terms of the equivalent impedance Zeq of the first and second circuits <NUM> and <NUM> shown in <FIG> is as follows.

In Equation <NUM>, L1 is an inductance of the first coil <NUM>, L2 is an inductance of the second coil <NUM>, and M is a mutual inductance. ω represents a (resonant) frequency, and C represents a capacitance of the capacitor of the first circuit <NUM>.

Referring to Equation <NUM>, the equivalent impedance Zeq of the first and second circuits <NUM> and <NUM> at a resonant frequency is briefly summarized as follows.

Referring to Equation <NUM> or Equation <NUM> above, it can be seen that the equivalent impedance Zeq of the first and second circuits <NUM> viewed from the capacitor C varies greatly according to a change in Rntc which is a resistance value of the NTC <NUM>. That is, the equivalent impedance Zeq is proportional to the resistance Rntc of the NTC <NUM>.

<FIG> is a graph illustrating a relationship between an impedance phase angle and a frequency. In addition, <FIG> is a graph illustrating a relationship between an impedance magnitude and a frequency.

Referring to <FIG> and <FIG>, it can be seen that the temperature estimation of the temperature estimation circuit using the NTC <NUM> is sufficiently possible.

As can be seen in <FIG> and <FIG>, it can be seen that both the phase angle and the magnitude of the equivalent impedance Zeq viewed from the first side (the first circuit <NUM>) change significantly.

At this time, as in <FIG>, if a distance between the first side (first circuit <NUM>) and the second side (second circuit <NUM>) is changed, the impedance phase angle is changed to specify a frequency to be measured. Thus, in order to compare two impedances, it may be necessary to specify a frequency.

In addition, as shown in <FIG>, the temperature may be estimated by measuring the magnitude of the impedance at the frequency specified above.

At this time, it can be seen that the magnitude of the impedance changes <NUM> times from 200Ω to <NUM> kΩ, which may mean that the discrimination power for temperature estimation is sufficient.

Hereinafter, a temperature estimation process under a specific simulation condition will be described with reference to <FIG> and <FIG>.

<FIG> is a graph illustrating a relationship between an impedance phase angle and a frequency under a simulation condition. In addition, <FIG> is a graph illustrating a relationship between an impedance magnitude and a frequency under a simulation condition. <FIG> is a graph illustrating a change in a resistance value according to a temperature of NTC.

At this time, the first side coil turn ratio of the first coil <NUM> and the second coil <NUM> is <NUM> to <NUM> (<NUM>:<NUM>), and a distance between the first circuit <NUM> and the second circuit <NUM> is <NUM>.

When a specific inductance L1, L2, M value for simulation is applied, and a distance between the first side (first circuit <NUM>) and the second side (second circuit <NUM>) is <NUM>, Equation <NUM> is summarized as follows. <MAT> <MAT>.

As shown in <FIG> and <FIG>, the Rntc value of the NTC <NUM> may be derived by using the phase of the equivalent impedance Zeq and the impedance magnitude at a specific frequency.

At this time, as shown in <FIG>, it can be seen that the Rntc value of the NTC <NUM> varies from <NUM> to <NUM>Ω, and at this time, the temperature of the NTC varies from <NUM> to <NUM>.

As described above, according to the present invention, the temperature of the drum <NUM> can be estimated with a sufficient accuracy by using a circuit shown in <FIG>.

According to an embodiment of the present invention as described above, accurate temperature estimation may be possible by using the characteristic of the NTC resistance that exponentially decreases depending on temperature.

In addition, it may be possible to estimate the temperature regardless of a distance that is structurally generated due to the drum and the tub.

In addition, accurate temperature estimation may be possible even under a rotating load (drum) condition.

In addition, since the temperature is estimated by using the NTC resistance, the influence on the inductance/capacitance distribution may be small.

For temperature estimation, since continuous temperature estimation is possible without turning off a power device, high efficiency can be achieved in case of being applied to a product.

<FIG> is a flowchart illustrating a method of controlling a laundry treating apparatus.

According to an embodiment of the present invention, the temperature of the drum <NUM> of the washing machine may be estimated by using the circuit as described with reference to <FIG>.

That is, due to an interaction between the first coil <NUM> included in the first circuit <NUM> and the second coil <NUM> included in the second circuit <NUM>, the resistance value of the NTC <NUM> and the temperature of the drum <NUM> can be estimated by comparing the impedance obtained by detecting the voltage and current values received from the second coil <NUM> with the equivalent impedance of the first and second circuits <NUM> and <NUM> viewed from the first circuit <NUM>.

Hereinafter, a process of estimating the temperature of the drum <NUM> of the laundry treating apparatus by using the first circuit <NUM> and the second circuit <NUM> will be described in detail with reference to <FIG> and <FIG> together.

First, a step S10 of driving the laundry treating apparatus may be performed. In this case, as mentioned above, the laundry treating apparatus may correspond to a washing machine, a dryer, and a washing machine (dryer-integrated washing machine) which is integrated with a dryer. Hereinafter, as a laundry treating apparatus of the present invention, a washing machine will be described as a representative example. However, the laundry treating apparatus of the present invention is not limited thereto.

The step S10 of driving the laundry treating apparatus may include a process S11 of heating and rotating the load (drum <NUM>).

In addition, the step S10 of driving the laundry treating apparatus may include a process S12 of applying a resonance frequency to the power supply unit <NUM> of the first circuit (first side <NUM>).

In addition, the step S10 of driving the laundry treating apparatus may include the process of aligning the first coil <NUM> (primary coil) and the second coil <NUM> (secondary coil). The process of aligning the first coil <NUM> (primary coil) and the second coil <NUM> (secondary coil) may be performed automatically or manually in the washing machine. In addition, in some cases, the process of aligning the first coil <NUM> (primary coil) and the second coil <NUM> (secondary coil) may be omitted.

When the process of aligning the first coil <NUM> (primary coil) and the second coil <NUM> (secondary coil) is performed, a process S11 of heating and rotating the load (drum <NUM>) may be performed after such an alignment process.

Thereafter, a step S20 of detecting the output value of the second circuit <NUM> through the first circuit <NUM> may be performed. In this case, the second circuit <NUM> may include the thermistor <NUM>. The thermistor <NUM> may be an NTC thermistor <NUM>.

The resistance of the NTC <NUM> may be changed by heating the drum <NUM>. Such a change in resistance may follow the graph shown in <FIG>. The change in a curve in this graph may vary according to the NTC <NUM>.

When the resistance of the NTC <NUM> changes and the drum <NUM> rotates, the output current (and/or voltage) of the NTC <NUM> may be transmitted to the first coil <NUM> through the second coil <NUM> (S21). That is, the output current (and/or voltage) by Rntc, which is the resistance value of the NTC <NUM> in the second side, may be transmitted to the first coil <NUM>.

Accordingly, in the first circuit <NUM>, the current (and/or voltage) reflecting Rntc may be detected (S22).

Then, a step S30 of calculating the equivalent impedance of the first and second circuits <NUM> may be performed by using the current (and/or voltage) value reflecting the detected Rntc.

The step S30 of calculating the equivalent impedance may include a process of determining the magnitude and phase angle of the equivalent impedance Zeq.

As mentioned above, impedance can be defined as the ratio of AC voltage and current which are generated in a reference point or applied to a specific object. An alternating signal, such as an AC voltage, has a phase. In order to compare the phases, it may be necessary for the frequencies of two signals have the same state. This is because comparing the phases may not be meaningful if the frequencies are different.

First, steps (S40, S41) of matching the impedance measured by an output value of the second circuit <NUM> with the resonance frequency of the equivalent impedance Zeq may be performed.

At this time, the steps (S40, S41) of matching the resonance frequency may include a step S40 of comparing the impedance measured by an output value of the second circuit <NUM> with the resonance frequency of the equivalent impedance Zeq to obtain an error, and a step S41 of compensating an error in the inductance value of the first coil <NUM>.

That is, if an error occurs by comparing the impedance measured by the output value of the second circuit <NUM> with the resonance frequency of the equivalent impedance Zeq, the error in the inductance value L1 of the first coil <NUM> can be compensated. In this case, the error value may include a capacitance value C.

Thus, an applied frequency applied to the power supply unit <NUM> of the first side <NUM> may be changed according to the compensated error value.

Next, steps (S50, S51) of matching the impedance measured by the output value of the second circuit <NUM> with the phase angle of the equivalent impedance Zeq may be performed.

That is, steps (S50, S51) of matching the phase angle may include a step S50 of comparing the impedance measured by the output value of the second circuit <NUM> and the phase angle of the equivalent impedance Zeq to obtain an error, and a step S51 of compensating the error of phase angle by using the rotation angle of the drum <NUM>.

That is, if an error occurs by comparing the impedance measured by the output value of the second circuit <NUM> and the phase angle of the equivalent impedance Zeq, compensation for the error using the rotation angle of the load (drum <NUM>) can be performed.

Through this process, when the frequency and phase angle of the impedance and the equivalent impedance Zeq coincide, a step S60 of estimating the temperature of the drum <NUM> through the thermistor NTC <NUM> with the magnitude of the equivalent impedance Zeq can be performed.

Claim 1:
A laundry treating apparatus comprising:
a tub (<NUM>);
a drum (<NUM>) rotatably provided in the tub (<NUM>);
an induction heater (<NUM>) which is fixed to the tub (<NUM>) while being spaced apart from the drum (<NUM>), and heats the drum (<NUM>);
characterized in that
a first circuit (<NUM>) comprising a first coil (<NUM>) installed in the tub (<NUM>);
a power supply unit (<NUM>) which applies AC power to the first coil (<NUM>); and
a second circuit (<NUM>) installed in the drum (<NUM>), the second circuit (<NUM>) comprising a second coil (<NUM>) disposed in a position overlapping with the first coil (<NUM>) in a length direction of a rotational central shaft of the drum (<NUM>) and a thermistor (<NUM>) whose resistance varies depending on temperature.