Power supply unit and washing machine

Abstract

This reduces the harmonic components in the power supply current without the need for a reactor. [Solution] The power supply unit 200 is connected to an AC power supply 700 and includes a rectifier circuit 210 that rectifies the power supply voltage from the AC power supply 700, a smoothing capacitor 220 connected to the rectifier circuit 210 that smooths the rectified power supply voltage and supplies it to multiple loads, and a control circuit 600 that controls the power supply to the main motor 320, the heat pump motor 420, and the fan motor 520. The control circuit 600 includes a determination unit 621 that determines whether the current I23 exceeds a threshold, and a limiting unit 622 that, if it is determined that the current I23 exceeds a threshold, limits the power supplied to the second motor other than the first motor, which is a specific motor among the main motor 320, the heat pump motor 420, and the fan motor 520.

Description

Technical Field

[0001] The present disclosure relates to a power supply device for an electric appliance and a washing machine.

Background Art

[0002] Patent Document 1 includes a converter that rectifies a power supply voltage, an inverter connected to the converter, and a control device that controls the operation of the inverter. The control device performs vibration suppression control to suppress vibration of the torque of the electric motor, and restricts a compensation value of the vibration suppression control so that a harmonic component included in the power supply current flowing between the AC power supply and the converter is reduced, and discloses a power conversion device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the technique disclosed in Patent Document 1 has a problem that the circuit scale increases because a reactor is connected between the rectifier circuit and the AC power supply.

[0005] The present disclosure has been made to solve such problems, and provides a power supply device and a washing machine that can reduce harmonic components included in a power supply current without providing a reactor.

Means for Solving the Problems

[0006] A power supply device in one aspect of the present disclosure is a power supply device for an electrical device, comprising: a rectifier circuit connected to an AC power source and rectifying a power supply voltage from the AC power source; a smoothing capacitor connected to the rectifier circuit and smoothing the rectified power supply voltage and supplying it to a plurality of loads; and a control circuit for controlling the power supply to the plurality of loads, wherein the control circuit comprises: a detection unit for detecting a physical quantity in the power supply device; a determination unit for determining whether the physical quantity exceeds a threshold; and, if it is determined that the physical quantity exceeds the threshold, a limiting unit for limiting the power supplied to a second load other than a first load, which is a specific load among the plurality of loads. [Effects of the Invention]

[0007] This disclosure demonstrates that harmonic components in the power supply current can be reduced without the need for a reactor. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view of the washing machine in Embodiment 1. [Figure 2] This is a circuit diagram of the power supply unit for the washing machine in Embodiment 1. [Figure 3] These are waveform diagrams of the harmonic components contained in the current output from the smoothing capacitor and the power supply current. [Figure 4] This is a detailed configuration diagram of the control circuit in Embodiment 1. [Figure 5] This flowchart shows a first example of the processing of the interlocking control unit in Embodiment 1. [Figure 6] This flowchart shows a second example of the processing of the interlocking control unit in Embodiment 1. [Figure 7] This flowchart shows a third example of the processing of the interlocking control unit in Embodiment 1. [Figure 8] This flowchart shows an example of the gate signal generation process in Embodiment 1. [Figure 9] This graph shows the temporal change in power consumption from an AC power source when interlocking control is not applied. [Figure 10] It is a graph showing the harmonic component suppression effect in the power supply device of Embodiment 1. [Figure 11] It is a circuit diagram of the power supply device of the washing machine in Embodiment 2. [Figure 12] It is a waveform diagram of each of the current output from the rectifier circuit and the voltage applied to the smoothing capacitor. [Figure 13] It is a waveform diagram of each of the harmonic components included in the voltage applied to the smoothing capacitor and the power supply current. [Figure 14] It is a detailed configuration diagram of the control circuit in Embodiment 2. [Figure 15] It is a flowchart showing the first example of the processing of the interlock control unit in Embodiment 2. [Figure 16] It is a flowchart showing the second example of the processing of the interlock control unit in Embodiment 2. [Figure 17] It is a flowchart showing the third example of the processing of the interlock control unit in Embodiment 2. [Figure 18] It is a graph showing the change over time of the threshold value changed by the threshold value setting unit. [Figure 19] It is a flowchart showing an example of the threshold value setting process. [Figure 20] It is a sequence diagram of the threshold value setting process. [Figure 21] In Modification 2 of the present disclosure, it is a graph showing the first example of the control pattern in the dehydration mode. [Figure 22] In Modification 2 of the present disclosure, it is a graph showing the second example of the control pattern in the dehydration mode. [Figure 23] In Modification 3 of the present disclosure, it is a graph showing an example of the control pattern in the drying mode.

Embodiments for Carrying Out the Invention

[0009] (Knowledge underlying the present disclosure) Electrical appliances such as washing machines use power supply units that include a rectifier circuit and smoothing capacitor that convert the AC power supply voltage to a DC voltage, and an inverter circuit that converts the DC voltage from the smoothing capacitor back to an AC voltage and supplies it to an AC load. Such power supply units have the problem of large harmonic components in the power supply current flowing between the AC power supply and the rectifier circuit. If the harmonic components become excessive, this affects the quality of the grid power supply. For this reason, such power supply units have limits set for each of the multiple harmonic components according to standards (standards of the Japan Electronics and Information Technology Industries Association).

[0010] If a reactor is placed between the rectifier circuit and the AC power supply, the reactor will function like a low-pass filter and reduce harmonic components. However, adding a reactor increases the circuit size. Also, if an AC load requiring a large current is connected to the inverter circuit, the current flowing through the reactor will be pulled towards the AC load, and the reactor alone may not be able to suppress harmonic components effectively.

[0011] On the other hand, some power supply devices employ a rectifier circuit with a voltage boosting function. In this case, since the rectifier circuit is equipped with a switching element, current can be supplied to the reactor at any desired timing, and harmonic components can be suppressed even when an AC load requiring a large current is connected to the inverter circuit. However, such a rectifier circuit with a voltage boosting function requires a reactor and a switching element, which increases the circuit size.

[0012] The power conversion device shown in Patent Document 1 balances the imbalance between the positive polarity power supply current and the negative polarity current supply by vibration suppression control, thereby reducing the harmonic components contained in the power supply current flowing between the AC power supply and the converter. However, the voltage conversion device shown in Patent Document 1 also requires a reactor, which increases the circuit size.

[0013] Incidentally, harmonic components tend to increase as the power supplied to the AC load increases, so if the power supplied to the AC load can be suppressed to an arbitrary value, the harmonic components can be suppressed. Some electrical devices have power supplies in which multiple AC loads are connected to a single rectifier circuit via multiple inverter circuits. In such electrical devices, depending on the operating mode, there are AC loads that are of higher importance among the multiple AC loads, and it is not always necessary to supply the required power to all AC loads. Furthermore, this is true not only for AC loads but also for DC loads.

[0014] Therefore, the inventors have come up with the idea for this disclosure based on the finding that by preferentially supplying power to high-priority loads while limiting the power supplied to low-priority loads, the total power supplied to all loads can be suppressed, thereby suppressing harmonic components without the need for a reactor.

[0015] The embodiments of the washing machine will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The accompanying drawings and the following explanation are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.

[0016] (Embodiment 1) Figure 1 is a schematic cross-sectional view of the washing machine 100 in Embodiment 1. This washing machine 100 washes and dries items such as clothing.

[0017] [Overall structure of the washing machine] The washing machine 100 includes a housing 110. The housing 110 has an opening into which the material to be processed is introduced. The housing 110 has a door 111 for opening and closing the opening. The housing 110 houses internal devices for performing the wash mode, rinse mode, spin-dry mode, and drying mode.

[0018] The housing 110 includes a water tank 114 and a rotating drum 115. The rotating drum 115 has a number of small holes 117 formed in its peripheral wall. The rotating drum 115 contains the material to be processed, which is fed in through the input port. The water tank 114 stores water in the washing and rinsing modes. The water tank 114 is elastically supported by a suspension mechanism 118 fixed to the bottom wall of the housing 110.

[0019] A water inlet 120 is provided at the top of the peripheral wall of the tank 114. The water inlet 120 supplies water to the tank 114 in washing mode and rinsing mode. A drain outlet 121 is provided at the bottom of the peripheral wall of the tank 114. The drain outlet 121 drains the water used for washing and rinsing.

[0020] An exhaust port 122 is formed on the upper part of the peripheral wall of the water tank 114. In drying mode, the exhaust port 122 exhausts air from the water tank 114 to dry the material being processed. An air inlet 123 is formed on the rear end wall of the water tank 114. In drying mode, the air inlet 123 allows the air exhausted from the exhaust port 122 to flow into the processing chamber 112.

[0021] A main motor 320 for rotating the rotating drum 115 is mounted on the outer surface of the rear end wall of the water tank 114.

[0022] A water supply unit 125 is provided above the water tank 114. The water supply unit 125 supplies water to the processing chamber 112. The upstream end of the water supply unit 125 is exposed on the outer surface of the housing 110 and is connected to a hose (not shown) extending from a water tap.

[0023] A drainage path 129 is provided on the underside of the tank 114. The drainage path 129 drains the water from the tank 114.

[0024] A circulating air passage 131 is provided on the outside of the water tank 114. The circulating air passage 131 is connected between the air intake 123 and the exhaust 122. A fan 152 is positioned inside the circulating air passage 131. The fan 152 draws air from the processing chamber 112 through the exhaust 122 and returns the drawn-out air to the processing chamber 112 through the air intake 123.

[0025] A dehumidifying unit 156 and an adsorbent material 139 are arranged within the circulating air passage 131. The dehumidifying unit 156 and the adsorbent material 139 remove moisture from the air flowing through the circulating air passage 131.

[0026] A heating unit 153 is positioned downstream of the dehumidifying unit 156 and the adsorbent 139. The dehumidifying unit 156 and the heating unit 153 constitute a heat pump device. The dehumidifying unit 156 includes an expansion valve for expanding the refrigerant and fins that are cooled by the expanded refrigerant. The heating unit 153 includes a compressor for compressing the refrigerant and fins that are heated by the compressed refrigerant.

[0027] [Circuit Configuration] Figure 2 is a circuit diagram of the power supply unit 200 of the washing machine 100 in Embodiment 1. The power supply unit 200 includes a rectifier circuit 210, a smoothing capacitor 220, and inverter circuits 310, 410, and 510.

[0028] The rectifier circuit 210 is connected to the AC power supply 700 and rectifies the power supply voltage from the AC power supply 700. The rectifier circuit 210 includes four diodes 11, 12, 13, and 14 connected in a full bridge configuration. The connection point between diode 11 and diode 13 is connected to one end of the AC power supply 700, forming the first AC input terminal 61. The connection point between diode 12 and diode 14 is connected to the other end of the AC power supply 700, forming the second AC input terminal 62. The rectifier circuit 210 full-wave rectifies the power supply voltage supplied from the AC power supply 700.

[0029] AC power supply 700 is a grid power supply that provides AC power at predetermined frequencies such as 50Hz and 60Hz.

[0030] The smoothing capacitor 220 smooths the power supply voltage rectified by the rectifier circuit 210. As a result, a DC voltage is generated between the positive node 64 and the negative node 65.

[0031] The smoothing capacitor 220 includes smoothing capacitors 21 and 22. One end of the smoothing capacitor 220 is connected to the cathodes of diodes 11 and 12, respectively, and to the positive node 64. The other end of the smoothing capacitor 220 is connected to the anodes of diodes 13 and 14, respectively, and to the negative node 65. The connection point 63 between smoothing capacitors 21 and 22 is connected to the other end of the AC power supply 700 via the second AC input terminal 62.

[0032] The power supply unit 200 further includes a current sensor 23. The current sensor 23 is configured, for example, as a shunt resistor and detects the current I23 output from the smoothing capacitor 220. The current sensor 23 is connected between one end of the smoothing capacitor 22 and the negative node 65.

[0033] Inverter circuits 310, 410, and 510 are each composed of three-phase inverter circuits. One end of each inverter circuit is connected to the positive node 64, and the other end is connected to the negative node 65.

[0034] The inverter circuit 310 converts the DC voltage output from the smoothing capacitor 220 into an AC voltage and supplies that AC voltage to the main motor 320.

[0035] The inverter circuit 410 converts the DC voltage output from the smoothing capacitor 220 into an AC voltage and supplies that AC voltage to the heat pump motor 420.

[0036] The inverter circuit 510 converts the DC voltage output from the smoothing capacitor 220 into an AC voltage and supplies that AC voltage to the fan motor 520.

[0037] The inverter circuit 310 includes switching elements 31, 32, 33, 34, 35, 36, and a current sensor 37. Switching elements 31 and 34 constitute a V-phase leg. The connection point of switching elements 31 and 32 is connected to the main motor 320 and constitutes a V-phase AC output terminal 72.

[0038] Switching element 32 and switching element 35 constitute a U-phase leg. The connection point of switching element 32 and switching element 35 is connected to the main motor 320 and constitutes a U-phase AC output terminal 71.

[0039] Switching element 33 and switching element 36 constitute a W-phase leg. The connection point of switching element 33 and switching element 36 is connected to the main motor 320 and constitutes a W-phase AC output terminal 73.

[0040] The switching elements 31-36 are composed of, for example, IGBTs (Insulated Gate Bipolar Transistors). However, this is just one example, and the switching elements 31-36 may also be composed of MOSFETs (metal-oxide-semiconductor field-effect transistors). Reverse flow diodes are connected to the switching elements 31-36. Reverse direction means the opposite direction to the forward direction, where the forward direction is defined as the direction in which current flows from the collector to the emitter.

[0041] The current sensor 37 is connected between the U-phase AC output terminal 71 and the main motor 320 to detect the load current I1. The load current I1 is the output AC current supplied to the main motor 320 by the inverter circuit 310. The current sensor 37 may be connected between the V-phase AC output terminal 72 or the W-phase AC output terminal 73 and the main motor 320, or between the negative node 65 and the emitter terminal of the V-phase switching element 34.

[0042] The inverter circuit 410 includes switching elements 41, 42, 43, 44, 45, 46, and a current sensor 47. Switching elements 41 and 44 constitute a V-phase leg. The connection point of switching elements 41 and 42 is connected to a heat pump motor 420 and constitutes a V-phase AC output terminal 82.

[0043] Switching element 42 and switching element 45 constitute a U-phase leg. The connection point of switching element 42 and switching element 45 is connected to the heat pump motor 420 and constitutes a U-phase AC output terminal 81.

[0044] Switching element 43 and switching element 46 constitute a W-phase leg. The connection point of switching element 33 and switching element 36 is connected to the heat pump motor 420 and constitutes a W-phase AC output terminal 83.

[0045] The configuration of switching elements 41-46 is the same as that of switching elements 31-36.

[0046] The current sensor 47 is connected between the U-phase AC output terminal 81 and the heat pump motor 420 to detect the load current I2. The load current I2 is the output AC current supplied to the heat pump motor 420 by the inverter circuit 410. The current sensor 47 may be connected between the V-phase AC output terminal 82 or the W-phase AC output terminal 83 and the heat pump motor 420, or between the negative node 65 and the emitter terminal of the V-phase switching element 44.

[0047] The inverter circuit 510 includes switching elements 51, 52, 53, 54, 55, 56, and a current sensor 57. Switching elements 51 and 54 constitute a V-phase leg. The connection point of switching elements 51 and 52 is connected to a fan motor 520 and constitutes a V-phase AC output terminal 92.

[0048] Switching element 52 and switching element 55 constitute a U-phase leg. The connection point of switching element 52 and switching element 55 is connected to the fan motor 520 and constitutes a U-phase AC output terminal 91.

[0049] Switching element 53 and switching element 56 constitute a W-phase leg. The connection point of switching element 53 and switching element 56 is connected to the fan motor 520 and constitutes a W-phase AC output terminal 93.

[0050] The configuration of switching elements 51-56 is the same as that of switching elements 31-36.

[0051] The current sensor 57 is connected between the U-phase AC output terminal 91 and the fan motor 520 to detect the load current I3. The load current I3 is the output AC current supplied to the fan motor 520 by the inverter circuit 510. The current sensor 57 may also be connected between the V-phase AC output terminal 92 or the W-phase AC output terminal 93 and the fan motor 520, or between the negative node 65 and the emitter terminal of the V-phase switching element 54.

[0052] The main motor 320 is a three-phase motor that rotates the rotating drum 115.

[0053] The heat pump motor 420 is a three-phase motor that drives the compressor that constitutes the heating unit 153.

[0054] The fan motor 520 is a three-phase motor that drives the fan 152.

[0055] The control circuit 600, for example, consists of a microcontroller and controls the washing machine 100. The control circuit 600 controls the power supply to the main motor 320, the heat pump motor 420, and 520.

[0056] The inverter circuit 310 and main motor 320, the inverter circuit 410 and heat pump motor 420, and the inverter circuit 510 and fan motor 520 are examples of multiple loads.

[0057] In the example shown in Figure 2, there are three loads, but this is just an example, and the number of loads may be two or four or more. The rectifier circuit 210 is composed of a voltage doubler rectifier circuit, but it may also be composed of a half-wave rectifier circuit or a full-wave rectifier circuit. In that case, the smoothing capacitor 220 is composed of smoothing capacitors 21 and 22, but it may also be composed of a single capacitor. Current sensors 37, 47, and 57 are examples of current detection units. Current sensor 23 is an example of a detection unit that detects physical quantities including motor current in the power supply unit 200.

[0058] Figure 3 shows the waveforms of the current I23 output from the smoothing capacitor 220 and the harmonic components contained in the power supply current. Current I23 is the current detected by the current sensor 23. In Figure 3, the upper panel shows the waveform of current I23, and the lower panel shows the waveforms of the harmonic components. In the waveform of current I23, the vertical axis is current and the horizontal axis is time. In the waveform of the harmonic components, the vertical axis is current and the horizontal axis is time, with the solid line showing the waveform 301 of the third harmonic component, the dotted line showing the waveform 302 of the fifth harmonic component, and the dashed line showing the waveform 303 of the seventh harmonic component.

[0059] As shown in Figure 3, when the current I23 increases, waveform 301 increases in proportion to the increase, and when the current I23 decreases, waveform 301 also decreases in proportion to the decrease. Thus, the current I23 and the third harmonic component have waveforms of almost the same shape, and they change in conjunction with each other. Also, when waveform 301 increases, waveforms 302 and 303 increase in proportion to the increase, and when waveform 301 decreases, waveforms 302 and 303 also decrease in proportion to the decrease. However, the amplitude of the waveform fluctuations decreases in the order of the third harmonic component, the fifth harmonic component, and the seventh harmonic component. Thus, the current I23 changes in conjunction with the third harmonic component, the fifth harmonic component, and the seventh harmonic component. Therefore, by monitoring the current I23, it is possible to determine whether or not the harmonic components exceed the limit value. Therefore, if the current I23 exceeds a threshold, the determination unit 621 (Figure 4) limits the power supply to the load in order to suppress harmonic components.

[0060] Figure 4 is a detailed configuration diagram of the control circuit 600 in Embodiment 1. The control circuit 600 includes a speed command generation unit 610, an interlocking control unit 620, a first drive unit 630, a second drive unit 640, and a third drive unit 650.

[0061] The speed command generation unit 610 generates speed command values ​​V11, V12, and V13 for the main motor 320, heat pump motor 420, and fan motor 520, respectively. Speed ​​command values ​​V11, V12, and V13 are target values ​​for the rotational speeds of the main motor 320, heat pump motor 420, and fan motor 520, respectively. The speed command generation unit 610 should generate speed command values ​​V11, V12, and V13 according to a predetermined control pattern for the target rotational speeds of the main motor 320, heat pump motor 420, and fan motor 520, depending on the operating mode of the washing machine 100.

[0062] The interlocking control unit 620 includes a determination unit 621 and a limiting unit 622. The determination unit 621 determines whether the current I23 exceeds a threshold. The threshold is a predetermined value of the current I23, where the values ​​of the harmonic components of each order included in the power supply current from the AC power supply 700 may exceed the limit values ​​defined by the standard.

[0063] The limiting unit 622, when it determines that the current I23 exceeds a threshold, limits the power supplied to the second motor (an example of a second load), excluding the first motor (an example of a first load), which is a specific motor among the main motor 320, heat pump motor 420, and fan motor 520. The number of first motors is, for example, one or more. The number of second motors is, for example, one or more. Note that the number of first and second motors may be just one.

[0064] The limiting unit 622 limits the power supplied to the second load by, for example, making the slope of the speed command value for the second motor gentler than the original speed command value, or by lowering the speed command value compared to the original speed command value.

[0065] Speed ​​command value V11 is the original speed command value for the main motor 320, and speed command value V21 is the limited speed command value for the main motor 320. Speed ​​command value V12 is the original speed command value for the heat pump motor 420, and speed command value V22 is the limited speed command value for the heat pump motor 420. Speed ​​command value V13 is the original speed command value for the fan motor 520, and speed command value V23 is the limited speed command value for the fan motor 520.

[0066] Furthermore, if the speed command value V11, speed command value V12, or speed command value V13 corresponds to the first motor, the limiting unit 622 outputs the speed command value V11, speed command value V12, or speed command value V13 as is, as speed command value V21, speed command value V22, or speed command value V23. In other words, the limiting unit 622 outputs the speed command value corresponding to the first motor as is to the first drive unit 630, the second drive unit 640, or the third drive unit 650.

[0067] The limiting unit 622 may, for example, determine as the first motor a predetermined priority motor from among the main motor 320, the heat pump motor 420, and the fan motor 520, according to the operating mode of the power supply unit 200.

[0068] Alternatively, the limiting unit 622 may determine the motor with the largest load current among the main motor 320, heat pump motor 420, and fan motor 520 as the first motor.

[0069] Alternatively, the limiting unit 622 may determine the motor with the largest load current among the main motor 320, heat pump motor 420, and fan motor 520 as the first motor, and determine a predetermined load other than the first motor as the second load according to the operating mode of the washing machine 100.

[0070] The first drive unit 630 outputs a gate signal to the inverter circuit 310. The first drive unit 630 includes a current command generation unit 631, a voltage command generation unit 632, and a gate signal generation unit 633.

[0071] The current command generation unit 631 generates current command values ​​for the U, V, and W phases using PI (proportional-integral) control so that the speed error between the speed command value V21 and the current speed V1 of the main motor 320 is zero. The current speed V1 is generated by differentiating sensing data detected by an angle sensor (not shown) such as a rotary encoder on the main motor 320 using a differentiator (not shown). If an angle sensor is not used, the current speed V1 may be estimated from the motor current.

[0072] The voltage command generation unit 632 generates voltage command values ​​for the U, V, and W phases using PI control so that the current error between the load current I1 and the respective current command values ​​for the U, V, and W phases is zero.

[0073] The gate signal generation unit 633 generates gate signals for each of the switching elements 31 to 36 by comparing the voltage command values ​​of the U, V, and W phases with a triangular wave, and inputs the generated gate signals to each of the switching elements 31 to 36. The gate signals are PWM signals.

[0074] The second drive unit 640 outputs a gate signal to the inverter circuit 410. The second drive unit 640 includes a current command generation unit 641, a voltage command generation unit 642, and a gate signal generation unit 643.

[0075] The current command generation unit 641 generates current command values ​​for the U, V, and W phases using PI (proportional-integral) control so that the speed error between the speed command value V22 and the current speed V2 of the heat pump motor 420 is zero. The current speed V2 is estimated from the motor current and voltage command values ​​of the heat pump motor 420.

[0076] The voltage command generation unit 642 generates voltage command values ​​for the U, V, and W phases using PI control so that the current error between the load current I2 and the respective current command values ​​for the U, V, and W phases is zero.

[0077] The gate signal generation unit 643 generates gate signals for each of the switching elements 41 to 46 by comparing the voltage command values ​​of the U, V, and W phases with a triangular wave, and inputs the generated gate signals to each of the switching elements 41 to 46.

[0078] The third drive unit 650 outputs a gate signal to the inverter circuit 510. The third drive unit 650 includes a current command generation unit 651, a voltage command generation unit 652, and a gate signal generation unit 653.

[0079] The current command generation unit 651 generates current command values ​​for the U, V, and W phases using PI (proportional-integral) control so that the speed error between the speed command value V23 and the current speed V3 of the fan motor 520 is zero. The current speed V3 is generated by differentiating sensing data detected by an angle sensor (not shown) such as a rotary encoder on the fan motor 520 using a differentiator (not shown). If an angle sensor is not used, the current speed V3 may be estimated from the motor current.

[0080] The voltage command generation unit 652 generates voltage command values ​​for the U, V, and W phases using PI control so that the current error between the load current I3 and the respective current command values ​​for the U, V, and W phases is zero.

[0081] The gate signal generation unit 653 generates gate signals for each of the switching elements 51 to 56 by comparing the voltage command values ​​of the U, V, and W phases with a triangular wave, and inputs the generated gate signals to each of the switching elements 51 to 56.

[0082] [Operation] Figure 5 is a flowchart showing a first example of the processing of the interlocking control unit 620 in Embodiment 1.

[0083] (Step S11) The current sensor 23 detects the current I23. The detected current I23 is input to the control circuit 600.

[0084] (Step S12) The determination unit 621 determines whether the current I23 is greater than the threshold.

[0085] (Step S13) The limiting unit 622 determines whether the priority motor is the main motor 320. If the priority motor is the main motor 320 (YES in step S13), the process proceeds to step S14; if the priority motor is not the main motor 320 (NO in step S13), the process proceeds to step S15. Whether or not a motor is a priority motor is predetermined according to the operating mode.

[0086] (Step S14) The limiting unit 622 generates speed command values ​​V22 and V23 by limiting the speed command values ​​V12 and V13 of the heat pump motor 420 and the fan motor 520, and inputs the generated speed command values ​​V22 and V23 to the current command generation unit 641 and the current command generation unit 651, respectively. In this case, the limiting unit 622 inputs the speed command value V11 of the main motor 320 as speed command value V21 to the current command generation unit 631.

[0087] For example, if the current I23 exceeds a threshold, the limiting unit 622 may generate a speed command value V22 that is a predetermined speed lower than the speed specified by the speed command value V12. In this case, the limiting unit 622 may generate the speed command value V23 in the same way as the speed command value V22.

[0088] Alternatively, the limiting unit 622 may generate the speed command value V22 by setting the slope at which the speed command value V22 increases to be smaller than the slope at which the speed command value V12 increases when the current I23 exceeds a threshold. In this case, the limiting unit 622 can generate the speed command value V23 in the same way as the speed command value V22. This lowers the acceleration rate of the speed command value V22 compared to the acceleration rate of the speed command value V12.

[0089] (Step S15) The limiting unit 622 determines whether the priority motor is the heat pump motor 420. If the priority motor is the heat pump motor 420 (YES in step S15), the process proceeds to step S16; if the priority motor is not the heat pump motor 420 (NO in step S15), the process proceeds to step S17.

[0090] (Step S16) The limiting unit 622 generates speed command values ​​V21 and V23 by limiting the speed command values ​​V11 and V13 of the main motor 320 and the fan motor 520, and inputs the generated speed command values ​​V21 and V23 to the current command generation unit 631 and the current command generation unit 651, respectively. In this case, the limiting unit 622 inputs the speed command value V12 of the heat pump motor 420 as speed command value V22 directly to the current command generation unit 641.

[0091] For example, if the current I23 exceeds a threshold, the limiting unit 622 may generate a speed command value V21 that is a predetermined speed lower than the speed specified by the speed command value V11. In this case, the limiting unit 622 may generate the speed command value V23 in the same way as the speed command value V21.

[0092] Alternatively, the limiting unit 622 may generate the speed command value V21 by setting the slope at which the speed command value V21 increases to be smaller than the slope at which the speed command value V11 increases when the current I23 exceeds a threshold. In this case, the limiting unit 622 can generate the speed command value V23 in the same way as the speed command value V21. This lowers the acceleration rate of the speed command value V21 compared to the acceleration rate of the speed command value V11.

[0093] (Step S17) The limiting unit 622 generates speed command values ​​V21 and V22 by limiting the speed command values ​​V11 and V12 of the main motor 320 and the heat pump motor 420, and inputs the generated speed command values ​​V21 and V22 to the current command generation unit 631 and the current command generation unit 641, respectively. In this case, the limiting unit 622 inputs the speed command value V13 of the fan motor 520 as speed command value V23 to the current command generation unit 651.

[0094] For example, if the current I23 exceeds a threshold, the limiting unit 622 may generate a speed command value V21 that is a predetermined speed lower than the speed specified by the speed command value V11. In this case, the limiting unit 622 may generate the speed command value V22 in the same way as the speed command value V21.

[0095] Alternatively, the limiting unit 622 may generate the speed command value V21 by setting the slope at which the speed command value V21 increases to be smaller than the slope at which the speed command value V11 increases when the current I23 exceeds a threshold. In this case, the limiting unit 622 can generate the speed command value V22 in the same way as the speed command value V21.

[0096] Once steps S14, S16, and S17 are completed, the process returns to step S11.

[0097] Figure 6 is a flowchart showing a second example of the processing of the interlocking control unit 620 in Embodiment 1. In the flowchart of the second example, the motor with the largest load current is determined as the first motor, rather than the priority motor.

[0098] The processing in steps S21 and S22 is the same as in steps S11 and S12. Also, the processing in steps S24, S26, and S27 is the same as in steps S14, S16, and S17.

[0099] (Step S23) The limiting unit 622 determines whether the motor with the largest load current (maximum motor) is the main motor 320. If the maximum motor is the main motor 320 (YES in step S23), the process proceeds to step S24. If the maximum motor is not the main motor 320 (NO in step S23), the process proceeds to step S25.

[0100] (Step S25) The limiting unit 622 determines whether the maximum motor is the heat pump motor 420. If the maximum motor is the heat pump motor 420 (YES in step S25), the process proceeds to step S26. If the maximum motor is not the heat pump motor 420 (NO in step S25), the process proceeds to step S27.

[0101] Once steps S24, S26, and S27 are completed, the process returns to step S21.

[0102] Figure 7 is a flowchart showing a third example of the processing of the interlocking control unit 620 in Embodiment 1. The flowchart of the third example has a configuration that combines the flowcharts of the first and second examples.

[0103] Steps S41 and S42 are the same as steps S11 and S12.

[0104] (Step S43) The limiting unit 622 determines whether the maximum motor is the main motor 320. If the maximum motor is the main motor 320 (YES in step S43), the process proceeds to step S45. If the maximum motor is not the main motor 320 (NO in step S43), the process proceeds to step S44.

[0105] (Step S44) The limiting unit 622 determines whether the maximum motor is the heat pump motor 420. If the maximum motor is the heat pump motor 420 (YES in step S44), the process proceeds to step S48. If the maximum motor is not the heat pump motor 420, i.e., if the maximum motor is the fan motor 520 (NO in step S44), the process proceeds to step S51.

[0106] (Step S45) The limiting unit 622 determines which of the heat pump motor 420 and the fan motor 520 has a higher priority, that is, which is the priority motor. If the priority motor is the heat pump motor 420 (heat pump motor in step S45), the process proceeds to step S46. If the priority motor is the fan motor 520 (fan motor in step S45), the process proceeds to step S47.

[0107] (Step S46) The limiting unit 622 limits the speed command value V13 of the fan motor 520 and generates a speed command value V23. An example of the method for limiting the speed command value V13 is the same as the method in step S14 described above.

[0108] (Step S47) The limiting unit 622 limits the speed command value V12 of the heat pump motor 420 and generates a speed command value V22. An example of a method for limiting the speed command value V12 is the same as the method in step S14 described above.

[0109] (Step S48) The limiting unit 622 determines which of the fan motor 520 and the main motor 320 has a higher priority, that is, which is the priority motor. If the priority motor is the fan motor 520 (fan motor in step S48), the process proceeds to step S49. If the priority motor is the main motor 320 (main motor in step S48), the process proceeds to step S50.

[0110] (Step S49) The limiting unit 622 limits the speed command value V11 of the main motor 320 and generates a speed command value V21. One example of a method for limiting the speed command value V11 is the same as the method in step S16 described above.

[0111] (Step S50) The limiting unit 622 limits the speed command value V13 of the fan motor 520 and generates a speed command value V23. An example of the method for limiting the speed command value V13 is the same as the method in step S14 described above.

[0112] (Step S51) The limiting unit 622 determines which of the main motor 320 and the heat pump motor 420 has a higher priority, that is, which is the priority motor. If the priority motor is the main motor 320 (main motor in step S51), the process proceeds to step S52. If the priority motor is the heat pump motor 420 (heat pump motor in step S51), the process proceeds to step S53.

[0113] (Step S52) The limiting unit 622 limits the speed command value V12 of the heat pump motor 420 and generates a speed command value V22. An example of a method for limiting the speed command value V12 is the same as the method in step S14 described above.

[0114] (Step S53) The limiting unit 622 limits the speed command value V11 of the main motor 320 and generates a speed command value V21. One example of a method for limiting the speed command value V11 is the same as the method in step S16 described above.

[0115] Once steps S46, S47, S49, S50, S52, and S53 are completed, the process returns to step S41.

[0116] Figure 8 is a flowchart showing an example of the gate signal generation process in Embodiment 1. The gate signal generation process is the same in the first drive unit 630, the second drive unit 640, and the third drive unit 650, so the first drive unit 630 will be used as an example to explain the process below.

[0117] (Step S30) The current command generation unit 631 obtains the speed command value V21 from the interlock control unit 620. The current command generation units 641 and 651 obtain the speed command values ​​V22 and V23, respectively, from the interlock control unit 620.

[0118] (Step S31) The current command generation unit 631 calculates the speed error between the speed command value V21 obtained in step S30 and the current speed V1 of the main motor 320.

[0119] (Step S32) The current command generation unit 631 calculates the current command values ​​for the U, V, and W phases so that the speed error calculated in step S31 becomes zero.

[0120] (Step S33) The current command generation unit 631 outputs the current command values ​​for the U, V, and W phases to the voltage command generation unit 632.

[0121] (Step S34) The voltage command generation unit 632 calculates the current error between the load current I1 and the current command values ​​for the U, V, and W phases.

[0122] (Step S35) The voltage command generation unit 632 calculates the voltage command values ​​for the U, V, and W phases so that the current error calculated in step S34 becomes zero.

[0123] (Step S36) The voltage command generation unit 632 outputs the respective voltage command values ​​for the U, V, and W phases to the gate signal generation unit 633.

[0124] (Step S37) The gate signal generation unit 633 generates gate signals for each of the switching elements 31 to 36 by comparing the voltage command values ​​of the U, V, and W phases with a triangular wave, and inputs the generated gate signals to each of the switching elements 31 to 36.

[0125] Once step S37 is completed, the process returns to step S30. The above process is repeated until the main motor 320 is driven.

[0126] [Examples] The upper part of Figure 9 is a graph showing the temporal progression of power input from the AC power supply 700 when interlocking control is applied, and the lower part of Figure 9 is a graph showing the temporal progression of the harmonic components of the power supply current from the AC power supply 700 when interlocking control is applied.

[0127] Interlocking control refers to the control described in Figures 5, 6, and 7, which is a control that limits the power supplied to the second motor in order to limit harmonic components when the current I23 exceeds a threshold.

[0128] Figure 9 shows the various waveforms when the washing, spin-drying, washing, spin-drying, and drying modes are executed in that order. As shown in the upper part of Figure 9, when interlocking control is applied, the power supply power is below the power reference value REF. As a result, as shown in the lower part of Figure 9, the 1st, 3rd, and 5th harmonic components decrease in conjunction with the decrease in power supply power. Consequently, it is possible to suppress the harmonic components from exceeding the limits specified in the standard.

[0129] Figure 10 is a graph showing the harmonic component suppression effect of the power supply device 200 of Embodiment 1. In Figure 10, the left figure shows the harmonic component graph when interlocking control is not applied, and the right figure shows the harmonic component graph when interlocking control is applied.

[0130] The solid line shows the experimental results obtained using a circuit simulator. In Figure 10, the vertical axis represents the harmonic component (A), and the horizontal axis represents the order.

[0131] As shown in the left diagram of Figure 10, when interlocking control is not applied, the 3rd, 5th, and 7th harmonic components are all high.

[0132] In contrast, when linked control is applied, as shown in the right-hand figure of Figure 10, harmonic components are significantly suppressed across all orders, and the suppression effect of harmonic components is particularly pronounced in the 3rd, 5th, and 7th orders.

[0133] [Effects, etc.] The power supply unit 200 limits the power supplied to the second motor (excluding the first motor), which is a specific motor, when the current I23 exceeds a threshold. This allows the power supply unit 200 to suppress the total power supplied to the main motor 320, the heat pump motor 420, and the fan motor 520 in cases where the harmonic components in the power supply current flowing between the rectifier circuit 210 and the AC power supply 700 are likely to exceed the limits set by the standard. As a result, the power supply unit 200 can suppress the harmonic components in the power supply current without the need for a reactor. On the other hand, in cases where the harmonic components are not likely to exceed the limits, the main motor 320, the heat pump motor 420, and the fan motor 520 are supplied with the required power, thus ensuring stable operation in the operating mode.

[0134] Furthermore, the power supply unit 200 can reliably limit the power supplied to the second motor by making the slope of the speed command value to the second motor gentler or by lowering the speed command value.

[0135] Furthermore, the power supply unit 200 does not limit the power supplied to motors with higher priority according to the operating mode, thereby ensuring stable operation of the operating mode while suppressing harmonic components.

[0136] Furthermore, since the power supply unit 200 determines the motor with the largest load current as the first motor, it can suppress harmonic components while ensuring stable operation of the operating mode.

[0137] (Embodiment 2) Embodiment 2 limits the power supply to the load using voltage V24 instead of current I23. In Embodiment 2, the same reference numerals are used for components that are the same as in Embodiment 1, and their descriptions are omitted.

[0138] Figure 11 is a circuit diagram of the power supply unit 200A of the washing machine 100 in Embodiment 2. Power supply unit 200A differs from power supply unit 200 in that it has a voltage sensor 24 instead of a current sensor 23. Also, in Embodiment 2, the control circuit 600 is referred to as control circuit 600A.

[0139] The voltage sensor 24 is connected between the positive node 64 and the negative node 65. The voltage sensor 24 detects the voltage V24, which is the voltage across the smoothing capacitor 22, and inputs it to the control circuit 600. The voltage sensor 24 is an example of a detection unit that detects physical quantities in the power supply unit 200.

[0140] Figure 12 shows the waveforms of the current I23 output from the rectifier circuit 210 and the voltage V24 applied to the smoothing capacitor 220. In Figure 12, the upper panel shows the waveform of the current I23, and the lower panel shows the waveform of the voltage V24. In the waveform of the current I23, the vertical axis represents current and the horizontal axis represents time. In the waveform of the voltage V24, the vertical axis represents voltage and the horizontal axis represents time.

[0141] As shown in Figure 12, when the current I23 increases, the voltage V24 decreases in proportion to the increase, and when the current I23 decreases, the voltage V24 increases in proportion to the decrease. Thus, the voltage V24 has a waveform that is the inverse of the current I23. That is, the voltage V24 has a negative correlation with the current I23, represented by a negative correlation coefficient α. The voltage drop V25 is the change in voltage V24 from the reference voltage Vref (here, approximately 240V) when the load is not operating, and is expressed as Vref-V24. The reference voltage Vref is the maximum value of voltage V24 because power is supplied from the AC power supply 700, but the load is not operating.

[0142] Figure 13 shows the waveforms of the voltage V24 applied to the smoothing capacitor 220 and the harmonic components contained in the power supply current. In Figure 13, the upper panel shows the waveform of the voltage V24, and the lower panel shows the waveforms of the harmonic components. The details of the lower panel waveform are the same as those of the lower panel waveform in Figure 3.

[0143] As shown in Figure 13, the voltage V24 and its harmonic components have a negative correlation, similar to the current I23 and voltage V24. Therefore, the determination unit 621A (Figure 14) limits the power supply to the load in order to suppress the harmonic components when the voltage V24 falls below a threshold.

[0144] Figure 14 is a detailed configuration diagram of the control circuit 600A in Embodiment 2. The control circuit 600A includes a speed command generation unit 610, an interlocking control unit 620A, a first drive unit 630, a second drive unit 640, and a third drive unit 650. The speed command generation unit 610, the first drive unit 630, the second drive unit 640, and the third drive unit 650 are the same as those in Embodiment 1.

[0145] The interlocking control unit 620A includes a determination unit 621A, a limiting unit 622, and a threshold setting unit 623. The determination unit 621A determines whether the voltage V24 has fallen below a threshold. The threshold is a predetermined value of the voltage V24 at which the values ​​of harmonic components of multiple orders contained in the power supply current from the AC power supply 700 may fall below the limit values ​​defined by the standard.

[0146] The limiting section 622 is the same as in Embodiment 1.

[0147] The threshold setting unit 623 decreases the threshold over time. The threshold setting unit 623 changes the initial value of the threshold according to the initial capacitance of the smoothing capacitor 220.

[0148] [Operation] Figure 15 is a flowchart showing a first example of the processing of the interlocking control unit 620A in Embodiment 2. The processing in Figure 15 differs from the processing in Figure 5 described in Embodiment 1 in steps S11A and S12A. Therefore, only steps S11A and S12A will be described, and the descriptions of the other steps will be omitted.

[0149] (Step S11A) The voltage sensor 24 detects the voltage V24. The voltage V24 is input to the control circuit 600A.

[0150] (Step S12A) The determination unit 621A determines whether the voltage V24 is less than the threshold value.

[0151] Figure 16 is a flowchart showing a second example of the processing of the interlocking control unit 620A in Embodiment 2. The processing in Figure 16 differs from the processing in Figure 6 described in Embodiment 1 in steps S21A and S22A. The processing in steps S21A and S22A is the same as steps S11A and S12A shown in Figure 15.

[0152] Figure 17 is a flowchart showing a third example of the processing of the interlocking control unit 620A in Embodiment 2. The processing in Figure 17 differs from the processing in Figure 7 described in Embodiment 1 in steps S41A and S42A. The processing in steps S41A and S42A is the same as steps S11A and S12A shown in Figure 15.

[0153] Figure 18 is a graph showing the change in the threshold over time as modified by the threshold setting unit 623. In Figure 18, the vertical axis represents the threshold, and the horizontal axis represents time.

[0154] The line 800 shows the change in the threshold value over time in the smoothing capacitor 220b, whose initial capacitance is the design value. Since the smoothing capacitor 220 deteriorates over time, the threshold setting unit 623 decreases the threshold value over time in accordance with this deterioration. The initial capacitance is the capacitance of the washing machine 100 shortly after it is manufactured.

[0155] Line 810 shows the change in threshold over time in smoothing capacitor 220c, where the initial capacitance is greater than the design value. Line 820 shows the change in threshold over time in smoothing capacitor 220a, where the initial capacitance is less than the design value. Lines 800, 810, and 820 are parallel lines, and are downward sloping lines where the threshold decreases as time passes. This is because although there is individual variation in initial capacitance, the degradation rate can be considered to be approximately constant. Note that smoothing capacitors 220a, 220b, and 220c each include smoothing capacitor 21 and smoothing capacitor 22, respectively, so the initial capacitance is, for example, the combined capacitance of the initial capacitances of smoothing capacitor 21 and smoothing capacitor 22.

[0156] A smoothing capacitor 220a with an initial capacitance smaller than the design value exhibits a greater voltage drop V25 compared to a smoothing capacitor 220b with an initial capacitance equal to the design value. Therefore, in a power supply 200A using a smoothing capacitor 220a, if the initial threshold value 801 corresponding to the smoothing capacitor 220b is adopted, the voltage V24 is more likely to fall below the threshold, potentially leading to unnecessary power limiting to the second load.

[0157] Therefore, if the initial voltage drop V251, which is the voltage drop V25 when any of the multiple loads is operated under constant load conditions in the initial stages of production, is greater than the reference value V250 of the initial voltage drop V251, the threshold setting unit 623 reduces the initial threshold value 801 according to the difference between the initial voltage drop V251 and the reference value V250. As a result, the initial threshold value of the power supply unit 200A that employs the smoothing capacitor 220a is set to the initial threshold value 821. The reference value V250 is the voltage drop V25 when any of the multiple loads is operated under constant load conditions in the power supply unit 200A that employs the smoothing capacitor 220b.

[0158] On the other hand, a smoothing capacitor 220c with an initial capacitance greater than the design value exhibits a reduced voltage drop V25 compared to a smoothing capacitor 220b with an initial capacitance equal to the design value. Therefore, in a power supply unit 200A using a smoothing capacitor 220c, if an initial threshold value of 801 is adopted, the voltage V24 will be less likely to fall below the threshold, potentially resulting in the failure to implement power limiting to the second load in situations where it should be implemented.

[0159] Therefore, if the initial voltage drop V251 is smaller than the reference value V250, the threshold setting unit 623 increases the initial threshold value 801 according to the difference between the initial voltage drop V251 and the reference value V250. As a result, the initial threshold value of the power supply unit 200A, which employs the smoothing capacitor 220c, is set to the initial threshold value 811.

[0160] Figure 19 is a flowchart illustrating an example of threshold setting processing. Threshold setting processing is performed, for example, when the washing machine 100 is first used. Threshold setting processing may also be performed, for example, when the power plug of the washing machine 100 is first connected to the outlet. Threshold setting processing may be performed before the washing machine 100 leaves the factory, or it may be performed when the washing machine 100 is installed.

[0161] (Step S101) The threshold setting unit 623 detects the voltage V24 when the main motor 320, heat pump motor 420, and fan motor 520 are in an unloaded state. This allows the reference voltage Vref to be obtained.

[0162] (Step S102) The threshold setting unit 623 sets current command values ​​to operate the main motor 320 under a constant load condition. In this case, the current command values ​​for the main motor 320 are, for example, 2A for the U phase, -1A for the V phase, and -1A for the W phase. This causes the main motor 320 to operate under a constant load condition. The constant load condition may also be determined by using a detection state that confirms whether the internal connector (not shown) of the washing machine 100 is correctly connected to the motor terminals. In the constant load condition, only the main motor 320 is operated, but at least one of the heat pump motor 420 and the fan motor 520 may be operated in place of or in addition to the main motor 320.

[0163] (Step S103) The threshold setting unit 623 obtains the voltage V24 from the voltage sensor 24 when the main motor 320 is operating under a constant load.

[0164] (Step S104) The threshold setting unit 623 subtracts the voltage detected in step S103 from the voltage V24 detected in step S101 to obtain the initial voltage drop V251, which is the voltage drop V25 when the main motor 320 is operated under a constant load, and stores the obtained initial voltage drop V251 in the memory shown in the figure.

[0165] (Step S105) The threshold setting unit 623 compares the initial voltage drop V251 with the reference value V250.

[0166] (Step S106) The threshold setting unit 623 sets the initial value of the threshold based on the comparison result. For example, the threshold setting unit 623 calculates the absolute value ΔV of the difference between the initial voltage drop V251 and the reference value V250. If the initial voltage drop V251 < reference value V250, the threshold setting unit 623 sets the initial value of the threshold 811 by adding the absolute value ΔV of the difference to the initial value of the threshold 801. For example, if the initial value of the threshold 801 is 210V, the initial voltage drop V251 is 3V, and the reference value V250 is 5V, then ΔV = 2V, so 210V + 2V = 212V is set as the initial value of the threshold 811.

[0167] On the other hand, the threshold setting unit 623 sets the initial threshold value 821 by subtracting the absolute difference ΔV from the initial threshold value 801 if the initial voltage drop V251 > reference value V250. For example, if the initial threshold value 801 is 210V, the initial voltage drop V251 is 6V, and the reference value V250 is 5V, then ΔV = 1V, so 210V - 1V = 209V is set as the initial threshold value 821.

[0168] Figure 20 is a sequence diagram of the threshold setting process. In Figure 20, the first row is the waveform diagram of voltage V24, the second row is the waveform diagram of the U-phase load current I1, the third row is the waveform diagram of the V-phase load current I2, and the fourth row is the waveform diagram of the W-phase load current I3. In the voltage drop 251 detection phase, load currents I1=2A, I2=-1A, and I3=-1A are supplied to the main motor 320. This brings the main motor 320 into a constant load state. The heat pump motor 420 and fan motor 520 are not supplied with current and are in an unloaded state.

[0169] When the main motor 320 is subjected to a constant load, an initial voltage drop V251 appears in the voltage V24. The threshold setting unit 623 sets the initial value of the threshold by comparing this initial voltage drop V251 with the reference value V250.

[0170] [Effects, etc.] Voltage V24 has a negative correlation with harmonic components. Therefore, by monitoring the voltage drop V25, it is possible to determine whether or not the harmonic components exceed the limit value. Power supply unit 200A detects voltage V24 as a physical quantity, and if the detected voltage V24 falls below the threshold, the power supplied to the second load is limited. As a result, power supply unit 200A can suppress harmonic components without using the load current flowing through each of the multiple loads.

[0171] Furthermore, in the power supply unit 200A, the initial voltage drop of the smoothing capacitor 220 is acquired, and the initial value of the threshold is changed by comparing the acquired initial voltage drop with the reference value of the initial voltage drop. Therefore, the initial value of the threshold can be set taking into account individual differences in initial capacitance.

[0172] The following variations of this disclosure may be adopted.

[0173] (Variation 1) The threshold setting unit 623 may calculate the rate of change of the voltage drop based on the history of the voltage drop V252, which is the voltage drop V25 across the smoothing capacitor 220 when any of the multiple loads is operated under a constant load condition.

[0174] Each time the washing machine 100 is in operation, the threshold setting unit 623 detects a voltage drop V252, for example, by setting the main motor 320 to a constant load state, and stores the detected voltage drop V252 in a memory (not shown in the figure) in association with the date and time of detection.

[0175] The threshold setting unit 623 calculates the rate of change, which indicates the change in voltage drop V252 over time, from the history of voltage drop V252. For example, the threshold setting unit 623 can calculate the rate of change by finding a regression line for the history of voltage drop V252 and then using the slope of this regression line. The threshold setting unit 623 changes the threshold based on the rate of change. For example, the time when the threshold was last changed is set to t -1 , the current time is t, and the previously changed threshold is TH t-1 If the rate of change is β, then the threshold setting unit 623 is THt-1 -β·Δt determines the threshold TH at the current time t. t Determine the following, where Δt = tt -1 That is the case.

[0176] As the capacitance of the smoothing capacitor 220 decreases over time, the voltage drop V252 increases over time. Therefore, if the threshold is fixed, the voltage V24 is more likely to fall below the threshold, potentially leading to unnecessary power limiting of the second load. Furthermore, the rate of decrease in capacitance over time may vary from one smoothing capacitor 220 to another. Consequently, the rate of change in the voltage drop may also vary from one capacitor to another. In this configuration, the rate of change in the voltage drop is calculated from the voltage drop history of the smoothing capacitor 220, and the threshold is lowered based on the calculated rate of change. This prevents unnecessary power loading to the second load.

[0177] (Modification 2) In embodiments 1 and 2, the power supply unit 200 limits the load to the second load when the current I23 exceeds a threshold or when the voltage V24 falls below a threshold. In modified example 2, the power supply unit 200 drives the main motor 320, the heat pump motor 420, and the fan motor 520 in the dehydration mode according to a predetermined control pattern.

[0178] Specifically, in the dehydration mode, when the control circuit 600 increases the speed command value V21 of the main motor 320, it limits the speed command value V22 of the heat pump motor 420 and also limits the speed command value V23 of the fan motor 520.

[0179] Figure 21 is a graph showing a first example of a control pattern in the dehydration mode in Modification 2 of the present disclosure. In Figure 21, the upper section shows the temporal changes of the speed command values ​​V21, V22, and V23 of the main motor 320, the middle section shows the speed command values ​​V21, V22, and V23 of the heat pump motor 420, and the lower section shows the speed command values ​​of the fan motor 520. The control circuit 600 suppresses harmonic components by driving the main motor 320, the heat pump motor 420, and the fan motor 520 according to the control pattern shown in Figure 21.

[0180] In Figure 21, the vertical axis represents the speed command value, and the horizontal axis represents time. This is also the case in Figures 22 and 23, which will be discussed later.

[0181] In the dehydration mode, the main motor 320 is important, so the speed command value V21 of the main motor 320 is controlled without restriction, while the speed command values ​​V22 of the heat pump motor 420 and the fan motor 520 are restricted, respectively.

[0182] In Figure 21, speeds VH, VL, and VM may have different values ​​for the main motor 320, heat pump motor 420, and fan motor 520, respectively. The same applies to Figures 22 and 23, which will be discussed later.

[0183] Since the main motor 320 is not subject to restrictions, the speed command value V21 is the same as the original speed command value V11.

[0184] Time T1 marks the start of the dehydration mode. During the period from time T1 to T2, the speed command value V21 increases linearly from zero to speed VH (high speed). During the period from time T2 to T3, the speed command value V21 remains at speed VH. During the period from time T3 to T4, the speed command value V21 decreases linearly from speed VH to zero. From time T4 onward, the speed command value V21 increases linearly from zero to speed VL (low speed), which is lower than speed VH, and after maintaining speed VL for a certain period, the speed decreases linearly to zero, repeating this intermittent operation periodically.

[0185] In dehydration mode, the speed command value V22 of the heat pump motor 420 is limited. Specifically, during the period from time T1 to T2, the speed command value V21 increases from zero to speed VH, and in conjunction with this increase, the speed command value V22 is limited to speed VL2 (second low speed), which is lower than speed VL1 (first low speed). That is, during the period from time T1 to T3, the speed command value V22 would normally maintain speed VL1, but during the period from time T1 to T2, it is limited (reduced) to speed VL2. As a result, during the period from time T1 to T2, when the power consumption of the main motor 320 is high, the speed command value V21 of the heat pump motor 420 is limited, thereby suppressing the harmonic components of the power supply current supplied from the AC power supply 700.

[0186] During the period from time T2 to T3, the speed command value V22 maintains speed VL1. During the period from time T3 to T4, the speed command value V21 decreases from speed VH to zero, and in conjunction with this decrease, the speed command value V22 increases from speed VL1 to speed VH. From time T4 onward, the speed command value V21 operates intermittently with a peak speed of VL, and in conjunction with this intermittent operation, the speed command value V22 maintains speed VH.

[0187] In dehydration mode, the speed command value V23 of the fan motor 520 is limited. Specifically, from the start (time T1) to the end of the dehydration mode, the speed command value V23 is limited from speed VM (or speed VH) to speed VL. This more reliably suppresses the harmonic components of the power supply current supplied from the AC power supply 700.

[0188] Thus, in the dehydration mode, the main motor 320 is of high importance, while the heat pump motor 420 and fan motor 520 are not as important as the main motor 320. When the speed command value of the main motor 320 increases, the power supply unit 200 limits the speed command value of the heat pump motor 420 and also limits the speed command value of the fan motor 520. Therefore, even without providing a reactor in the rectifier circuit 210, the total power of the main motor 320, heat pump motor 420, and fan motor 520 is reduced, and harmonic components can be suppressed in the dehydration mode.

[0189] Figure 22 is a graph showing a second example of a control pattern in the dehydration mode in Modification 2 of the present disclosure. In Figure 22, the upper section shows the temporal changes of the speed command values ​​V21, V22, and V23 of the main motor 320, the middle section shows the speed command values ​​V21, V22, and V23 of the heat pump motor 420, and the lower section shows the speed command values ​​of the fan motor 520. The control circuit 600 suppresses harmonic components by driving the main motor 320, the heat pump motor 420, and the fan motor 520 according to the control pattern shown in Figure 22.

[0190] The second example of the control pattern differs from the first example in how the speed command value V22 of the heat pump motor 420 is limited. In the second example, at time T0, a predetermined time before time T1, the speed command value V22 is set to speed VL2. Then, the speed command value V22 is maintained at speed VL2 from period T0 to time T21, between time T2 and time T3. More specifically, the speed command value V22 maintains speed VL2 for a longer period from time T0 to time T21 than the acceleration period of the main motor 320 from time T1 to time T2. In other words, the timing of the first rise of the speed command value V22 is moved forward from time T1 to time T0, and consequently, the timing of the second rise of the speed command value V22 is moved backward from time T2 to time T21. This allows the heat pump motor 420 to be started prior to the start timing of the dewatering mode while suppressing power consumption. Furthermore, the rise time of the speed command value V23 has also been moved forward from time T1 to time T0.

[0191] (Variation 3) In modified example 3, the power supply unit 200 drives the main motor 320, the heat pump motor 420, and the fan motor 520 in drying mode according to a predetermined control pattern.

[0192] Specifically, in drying mode, when the power supply unit 200 increases the speed command value V22 of the heat pump motor 420, it limits the speed command value V23 of the fan motor 520 and also limits the speed command value V21 of the main motor 320.

[0193] Figure 23 is a graph showing an example of a control pattern in drying mode in Modification 3 of the present disclosure. In Figure 23, the upper section shows the temporal progression of the speed command values ​​V21, V22, and V23 of the main motor 320, the middle section shows the speed command values ​​V21, V22, and V23 of the heat pump motor 420, and the lower section shows the speed command values ​​of the fan motor 520. The control circuit 600 suppresses harmonic components by driving the main motor 320, the heat pump motor 420, and the fan motor 520 according to the control pattern shown in Figure 23.

[0194] In drying mode, the heat pump motor 420 is important, so its speed command value V22 is not restricted, while the main motor 320 and fan motor 520 are restricted by speed command values ​​V21 and V23, respectively.

[0195] Since the heat pump motor 420 is not subject to restrictions, the speed command value V22 is the same as the original speed command value V12.

[0196] Time T1 marks the start of the drying mode. During the period from time T1 to T2, the speed command value V22 increases linearly from speed VL (low speed) to speed VH (high speed). During the period from time T2 to T3, the speed command value V22 remains at speed VH. During the period from time T3 to T4, the speed command value V22 decreases linearly from speed VH to speed VM (medium speed), which is intermediate between speed VH and speed VL. From time T4 onward, the speed command value V22 remains at speed VM.

[0197] In drying mode, the speed command value V23 of the fan motor 520 is limited. Specifically, during the period from time T1 to T2, the speed command value V22 increases from speed VL to speed VH, and in conjunction with this increase, the speed command value V23 decreases from speed VH to speed VM. During the period from time T2 to T3, the speed command value V22 maintains speed VH, and in conjunction with this maintenance, the speed command value V23 maintains speed VM. During the period from time T3 to T4, the speed command value V22 of the heat pump motor 420 decreases from speed VH to speed VM, and in conjunction with this decrease, the speed command value V23 increases from speed VM to speed VH. From time T4 onward, the speed command value V22 of the heat pump motor 420 maintains speed VM, and in conjunction with this maintenance, the speed command value V23 maintains speed VH.

[0198] In drying mode, the speed command value V21 of the main motor 320 is limited. Specifically, the speed command value V21 periodically repeats an intermittent operation in which it rises from zero to speed VL, maintains speed VL for a certain period, and then decreases back to zero. Although the speed command value V21 operates intermittently, its peak is limited to speed VL. As a result, the power consumption of the main motor 320 is suppressed, and the high-frequency components of the power supply current supplied from the AC power supply 700 can be further suppressed.

[0199] In drying mode, the heat pump motor 420 is of high importance, while the fan motor 520 and main motor 320 are not as important. According to Modification 3, when the speed command value of the heat pump motor 420 is increased, the speed command values ​​of the fan motor 520 and main motor 320 are limited. Therefore, the power supply unit 200 can suppress the total power of the main motor 320, heat pump motor 420, and fan motor 520 and suppress harmonic components in drying mode, even without providing a reactor in the rectifier circuit 210.

[0200] (Modification 4) In the examples in Figures 2 and 11, the main motor 320, heat pump motor 420, and fan motor 520 are all AC loads, but multiple DC loads may be connected instead of AC loads. In this case, the multiple DC loads are connected to the output side of the smoothing capacitor 220, i.e., between the positive node 64 and the negative node 65. In this case, the inverter circuits 310, 410, and 510 are not connected to the smoothing capacitor 220.

[0201] (Variation 5) The electrical appliance is not limited to the washing machine 100, but can be any electrical appliance that has a power supply unit with multiple loads connected to a single rectifier circuit. Other examples of electrical appliances include dishwashers, air conditioners, and refrigerators.

[0202] (Technology 1) A power supply device in one aspect of the present disclosure is a power supply device for an electrical device, comprising: a rectifier circuit connected to an AC power source and rectifying a power supply voltage from the AC power source; a smoothing capacitor connected to the rectifier circuit and smoothing the rectified power supply voltage and supplying it to a plurality of loads; and a control circuit for controlling the power supply to the plurality of loads, wherein the control circuit comprises: a detection unit for detecting a physical quantity in the power supply device; a determination unit for determining whether the physical quantity exceeds a threshold; and, if it is determined that the physical quantity exceeds the threshold, a limiting unit for limiting the power supplied to a second load other than a first load, which is a specific load among the plurality of loads.

[0203] This configuration limits the power supplied to a second load (other than the first load) when a physical quantity in the power supply unit exceeds a threshold. This allows the total power supplied to multiple loads to be suppressed in cases where the harmonic components in the power supply current flowing between the rectifier circuit and the AC power supply are likely to exceed the limits set by the standard. As a result, this configuration can suppress the harmonic components in the power supply current without the need for a reactor. On the other hand, in cases where the likelihood of the harmonic components exceeding the limits is low, the power required by multiple loads is supplied, ensuring stable operation in the operating mode.

[0204] (Technology 2) In the power supply device described in Technical 1, the detection unit may detect the current output from the rectifier circuit as the physical quantity, and the determination unit may determine that the current has exceeded the threshold value if the current exceeds the threshold value.

[0205] The current output from the rectifier circuit changes in conjunction with the harmonic components contained in the AC current output from the AC power supply. Therefore, by monitoring this current, it is possible to determine whether or not the harmonic components exceed a limit value. In this configuration, the current flowing from the rectifier circuit is detected as a physical quantity, and if the detected current exceeds a threshold, the power supplied to the second load is limited. Therefore, this configuration can suppress harmonic components without using multiple load currents flowing through each of the multiple loads.

[0206] (Technology 3) In the power supply device described in Technology 1 or 2, the detection unit may detect the voltage of the smoothing capacitor as the physical quantity, and the determination unit may determine that the voltage has exceeded the threshold if it falls below the threshold.

[0207] The voltage across a smoothing capacitor has a negative correlation with the harmonic components contained in the AC current output from the AC power supply. Therefore, by monitoring the voltage drop, it is possible to determine whether or not the harmonic components exceed a limit. In this configuration, the voltage across the smoothing capacitor is detected as a physical quantity, and if the detected voltage falls below a threshold, the power supplied to the second load is limited. Therefore, this configuration can suppress harmonic components without using the load current flowing through each of the multiple loads.

[0208] (Technology 4) In the power supply device described in any of Technical 1 to 3, the limiting unit may limit the power supplied to the second load by making the slope of the speed command value for the second load gentler, or by lowering the speed command value.

[0209] This configuration allows for reliable limiting of the power supplied to the second load by making the slope of the speed command value to the second load gentler or by lowering the speed command value.

[0210] (Technology 5) In the power supply device described in any of Technical 1 to 4, the limiting unit may determine a predetermined load as the first load according to the operating mode of the electrical equipment.

[0211] This configuration does not limit the power supplied to a predetermined load according to the operating mode, thus ensuring stable operation of the operating mode while suppressing harmonic components.

[0212] (Technology 6) In the power supply device described in any of Technical 1 to 5, a load current detection unit is further provided for detecting the load current flowing through each of the plurality of loads, and the limiting unit may determine the load with the largest load current as the first load.

[0213] This configuration determines the load with the maximum load current as the first load, thereby ensuring stable operation in the operating mode while suppressing harmonic components.

[0214] (Technology 7) In the power supply device described in any of Technical 1 to 6, the power supply device further comprises a load current detection unit that detects the load current flowing through each of the plurality of loads, and the limiting unit may determine the load with the largest load current as the first load, and determine a load other than the first load, which is predetermined according to the operating mode of the electrical equipment, as the second load.

[0215] In this configuration, the load with the maximum load current is determined as the first load, and among the loads other than the first load, a predetermined load according to the operating mode is determined as the second load. Therefore, high-frequency components can be suppressed more reliably while ensuring stable operation of the operating mode.

[0216] (Technology 8) The power supply device described in Technical 3 may further include a threshold setting unit that calculates the rate of change of the voltage drop based on the voltage drop history of the smoothing capacitor and lowers the threshold based on the rate of change.

[0217] As smoothing capacitors degrade over time, their capacitance decreases, causing their voltage drop to increase over time. Therefore, if the threshold is fixed, the voltage across the smoothing capacitor is more likely to fall below the threshold, potentially leading to unnecessary power limiting to the second load. Furthermore, since the rate of capacitance decrease over time varies from one smoothing capacitor to another, the rate of change in voltage drop also varies from one capacitor to another. In this configuration, the rate of change in voltage drop is calculated from the voltage drop history of the smoothing capacitor, and the threshold is lowered based on the calculated rate of change. This prevents unnecessary power loading to the second load.

[0218] (Technology 9) The power supply device described in Technical 3 may further include a threshold setting unit that acquires the initial voltage drop of the smoothing capacitor and changes the initial value of the threshold by comparing the initial voltage drop with a reference value of the initial voltage drop.

[0219] Since the initial capacitance of smoothing capacitors varies from one unit to another, the initial voltage drop of the smoothing capacitor also varies from unit to unit. With this configuration, the initial voltage drop of the smoothing capacitor is obtained, and the initial value of the threshold is changed by comparing the obtained initial voltage drop with a reference value for the initial voltage drop. Therefore, the initial value of the threshold can be set taking into account the individual differences in initial capacitance.

[0220] (Technology 10) In the power supply device described in Technical 9, the threshold setting unit may, when the initial voltage drop is smaller than the reference value, calculate the difference between the initial voltage drop and the reference value and set the initial value of the threshold by adding the absolute value of the difference to the initial value of the threshold; or, when the initial voltage drop is larger than the reference value, set the initial value of the threshold by subtracting the absolute value of the difference from the initial value of the threshold.

[0221] This configuration allows for more accurate setting of the initial threshold value, taking into account individual differences in initial capacitance.

[0222] (Technology 11) In the power supply device described in any of the Techniques 1 to 10, each of the plurality of loads includes an inverter circuit and a motor driven by the inverter circuit, and the power supply device may also include a plurality of inverter circuits connected to the smoothing capacitor.

[0223] This configuration is applicable to AC loads because each of the multiple loads consists of an inverter circuit and a motor driven by the inverter circuit.

[0224] (Technology 12) A washing machine in another aspect of this disclosure comprises a power supply device as described in any of the Art 1 to 11. [Industrial applicability]

[0225] This disclosure can suppress harmonic components without the need for a reactor, and is therefore applicable to electrical equipment connected to a grid power supply. [Explanation of symbols]

[0226] 21: Smoothing Capacitor 22: Smoothing Capacitor 23: Current Sensor 24: Voltage sensor 37: Current sensor 47: Current Sensor 57: Current Sensor 61: First AC input terminal 62: Second AC input terminal 63: Connection point 64: Positive side node 65: Negative side node 100: Washing machine 220: Smoothing Capacitor 310: Inverter Circuit 320: Main motor 410: Inverter Circuit 420: Heat pump motor 510: Inverter Circuit 520: Fan motor 600: Control circuit 610: Speed ​​command generation section 620: Interlocking Control Unit 621: Judgment section 622: Restriction section 623: Threshold setting section 630: First drive unit 631:Current command generation section 632: Voltage command generation unit 633: Gate signal generation unit 640: Second drive unit 641:Current command generation section 642: Voltage command generation unit 643: Gate signal generation unit 650: Third drive unit 651:Current command generation section 652: Voltage command generation unit 653: Gate signal generation unit 700: AC power supply

Claims

1. A power supply unit for electrical equipment, A rectifier circuit connected to an AC power source and which rectifies the power supply voltage from the AC power source, A smoothing capacitor connected to the rectifier circuit, which smooths the rectified power supply voltage and supplies it to multiple loads, The system includes a control circuit that controls the supply of power to the plurality of loads, The aforementioned control circuit is The power supply unit includes a detection unit for detecting physical quantities, A determination unit for determining whether the aforementioned physical quantity exceeds a threshold, The system includes a limiting unit that, when it is determined that the aforementioned physical quantity exceeds the threshold, limits the power supplied to a second load other than the first load, which is a specific load among the plurality of loads, power supply.

2. The detection unit detects the current output from the rectifier circuit as the physical quantity, The determination unit determines that the current has exceeded the threshold value if the current exceeds the threshold value. The power supply device according to claim 1.

3. The detection unit detects the voltage of the smoothing capacitor as the physical quantity, The determination unit determines that the voltage has exceeded the threshold if it falls below the threshold. The power supply device according to claim 1.

4. The limiting unit limits the power supplied to the second load by making the slope of the speed command value with respect to the second load gentler, or by lowering the speed command value. The power supply device according to claim 1.

5. The limiting unit determines a predetermined load as the first load according to the operating mode of the electrical equipment. The power supply device according to claim 1 or 2.

6. The system further includes a load current detection unit that detects the load current flowing through each of the aforementioned multiple loads, The limiting unit determines the load with the largest load current as the first load. The power supply device according to claim 1 or 2.

7. The system further includes a load current detection unit that detects the load current flowing through each of the aforementioned multiple loads, The limiting unit determines the load with the maximum load current as the first load, and determines a load other than the first load, which is predetermined according to the operating mode of the electrical equipment, as the second load. The power supply device according to claim 1.

8. Based on the voltage drop history of the smoothing capacitor, the rate of change of the voltage drop is calculated. The system further includes a threshold setting unit that lowers the threshold based on the rate of change. The power supply device according to claim 3.

9. The system further includes a threshold setting unit that obtains the initial voltage drop of the smoothing capacitor and changes the initial value of the threshold by comparing the initial voltage drop with a reference value of the initial voltage drop. The power supply device according to claim 3.

10. The threshold setting unit, when the initial voltage drop is smaller than the reference value, calculates the difference between the initial voltage drop and the reference value and sets the initial value of the threshold by adding the absolute value of the difference to the initial value of the threshold; when the initial voltage drop is larger than the reference value, it sets the initial value of the threshold by subtracting the absolute value of the difference from the initial value of the threshold. The power supply device according to claim 9.

11. Each of the aforementioned plurality of loads includes an inverter circuit and a motor driven by the inverter circuit. The power supply device includes a plurality of inverter circuits connected to the smoothing capacitor, A power supply device according to any one of claims 1 to 3.

12. A washing machine comprising a power supply device according to any one of claims 1 to 3.

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