JP6605836B2 - Motor drive device for washing machine - Google Patents

Description

  The present invention relates to an apparatus for driving a motor of a washing machine having a reactor between an AC power source and a rectifier circuit.

  For example, in Patent Document 1, a reactor, a rectifier circuit that generates a DC power supply, and a means for short-circuiting the AC input terminals of the rectifier circuit are connected between an AC power supply and an inverter circuit, and a half of the AC power supply voltage is obtained. Within the period, the AC input terminals are short-circuited a plurality of times, current is passed through the reactor, and the DC power supply bus voltage is boosted.

JP 2010-273505 A

  However, in the boost control of Patent Document 1, if the number of short circuits is increased in order to obtain a high boost effect, the fluctuation of the power supply current value increases and the harmonic current increases each time a short circuit is performed. In addition, a method has been proposed in which a short circuit is started from the zero crossing point of the AC power supply voltage, and the boosting effect is adjusted by adjusting the short circuit duration, but there is a limit to the electromagnetic energy that can be stored in the reactor within the short circuit time. There is. In addition, if the short-circuit time is lengthened, the distortion of the power source current waveform also increases, leading to an increase in harmonic current.

  Therefore, a motor driving device for a washing machine that can obtain a high boosting effect and suppress an increase in harmonic current is provided.

According to the motor drive device of the washing machine of the embodiment,
A rectifier circuit connected to an AC power source via a reactor;
Short-circuit means for short-circuiting between the input terminals of the rectifier circuit;
An inverter circuit that is connected to the output side of the rectifier circuit to convert DC power into AC power and drives a motor that generates at least rotational driving force for performing dehydration operation;
In accordance with a change in control parameters when performing the dehydration operation, short circuit control means for changing the number of times the input terminals are short-circuited between zero-cross timings of the voltage waveform of the AC power supply by the short circuit means,
The short-circuit control means controls to perform in the first half of the half cycle when the short-circuit is performed a plurality of times within a half cycle of the AC power supply, and causes a current peak value each time a current change occurs due to a short circuit. Increase.

The figure which is 1st Embodiment and shows schematically the drive control system of each motor in a washing-drying machine Longitudinal side view showing the configuration of a drum-type washing and drying machine Flow chart schematically showing the operation of the dehydration operation The flowchart which shows the start / end determination processing of pressure | voltage rise control A flowchart showing the start-up process of the boost control Flowchart showing second and subsequent short-circuit operation processing Diagram showing an example of actual power supply voltage / current waveform The figure which shows an example of the power supply voltage and electric current waveform at the time of performing the pressure | voltage rise control of patent document 1 The figure which shows an example of the result of having measured the harmonic current value about the pressure | voltage rise control of this embodiment The figure which shows an example of the result of having measured the harmonic current value about the pressure | voltage rise control of patent document 1 The figure which shows an example of a power supply voltage and a current waveform at the time of setting the output interval of a pulse longer than the case shown in FIG. The figure which shows an example of the result of having measured the harmonic current value The figure which is 2nd Embodiment, and shows the numerical example which changes the delay time of the short circuit pulse output for the first time according to the alternating current value in step S13, and the short circuit time by each pulse. Functional block diagram showing the configuration of the control system according to the third embodiment

(First embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 12. FIG. 2 is a longitudinal side view showing the configuration of the drum type washing and drying machine. The outer box 1 has a hollow shape including a front plate, a rear plate, a left side plate, a right side plate, a bottom plate, and a top plate. A front plate of the outer box 1 is formed with a through-hole shaped entrance 2. A door 3 is attached to the front plate of the outer box 1. The door 3 can be operated by the user between the closed state and the open state from the front. The door 2 is closed when the door 3 is closed, and the door 2 is opened when the door 3 is open. A water receiving tank 4 is fixed inside the outer box 1. The water receiving tank 4 has a cylindrical shape with a closed rear surface, and is arranged in an inclined state in which the axial center line CL descends from the front toward the rear. The front surface of the water receiving tank 4 is open. When the door 3 is closed, the door 3 closes the front surface of the water receiving tank 4 in an airtight state.

  A drum motor 5 is fixed to the rear plate of the water receiving tank 4 so as to be located outside the water receiving tank 4. The drum motor 5 is a DC brushless motor capable of speed control, and the rotating shaft 6 of the drum motor 5 protrudes into the water receiving tank 4. The rotating shaft 6 is disposed so as to overlap the axial center line CL of the water receiving tank 4, and the drum 7 is fixed to the rotating shaft 6 so as to be located inside the water receiving tank 4. The drum 7 has a cylindrical shape with a closed rear surface, and rotates integrally with the rotary shaft 6 when the drum motor 5 is in operation. The front surface of the drum 7 faces the inlet / outlet 2 from the rear via the front surface of the water receiving tank 4. Inside the drum 7, the door 2 is opened and the front of the inlet / outlet 2, the front of the water receiving tank 4 and the drum 7 are opened from the front. Laundry is put in and out through the front.

  A plurality of through holes 8 are formed in the drum 7, and the internal space of the drum 7 is connected to the internal space of the water receiving tank 4 through each of the plurality of through holes 8. A plurality of baffles 9 are fixed to the drum 7. Each of the plurality of baffles 9 moves in the circumferential direction around the axis line CL as the drum 7 rotates, and the laundry in the drum 7 is caught by each of the plurality of baffles 9. While moving in the circumferential direction, it is stirred by dropping by gravity.

  A water supply valve 10 is fixed inside the outer box 1. The water supply valve 10 has an inlet and an outlet, and the inlet of the water supply valve 10 is connected to a water tap. This water supply valve 10 uses a water supply valve motor 11 (see FIG. 2) as a drive source, and the outlet of the water supply valve 10 is switched between an open state and a closed state according to the amount of rotation of the water supply valve motor 11. The outlet of the water supply valve 10 is connected to a water injection case 12, and tap water is injected into the water injection case 12 through the water supply valve 10 when the water supply valve 10 is open, and tap water is injected when the water supply valve 10 is closed. It is not injected into the case 12. The water injection case 12 is fixed inside the outer box 1 at a higher position than the water receiving tank 4 and has a cylindrical water inlet 13. The water injection port 13 is inserted into the water receiving tank 4, and the tap water injected from the water supply valve 10 into the water injection case 12 is injected into the water receiving tank 4 from the water injection port 13.

  An upper end portion of a drain pipe 14 is connected to the water receiving tank 4 at the bottom, and a drain valve 15 is interposed in the drain pipe 14. This drain valve 15 uses a drain valve motor 16 (see FIG. 2) as a drive source, and is switched between an open state and a closed state according to the amount of rotation of the drain valve motor 16. In the closed state of the drain valve 15, tap water injected into the water receiving tank 4 from the water inlet 13 is stored in the water receiving tank 4, and in the open state of the drain valve 15, tap water in the water receiving tank 4 passes through the drain pipe 14. It is discharged outside the water receiving tank 4.

  A main duct 17 is fixed to the bottom plate of the outer box 1 below the water receiving tank 4. The main duct 17 has a cylindrical shape directed in the front-rear direction, and the lower end of the front duct 18 is connected to the front end of the main duct 17. The front duct 18 has a cylindrical shape directed in the vertical direction, and the upper end of the front duct 18 is connected to the internal space of the water receiving tank 4 at the front end of the water receiving tank 4. A fan casing 19 is fixed to the rear end portion of the main duct 17. The fan casing 19 has a through-hole-like intake port 20 and a cylindrical exhaust port 21, and the internal space of the fan casing 19 is connected to the internal space of the main duct 17 via the intake port 20.

  A fan motor 22 is fixed to the fan casing 19 outside the fan casing 19. The fan motor 22 has a rotating shaft 23 protruding into the fan casing 19, and a fan 24 is fixed to the rotating shaft 23 so as to be located inside the fan casing 19. The fan 24 is a centrifugal type that sucks air from the axial direction and discharges it in the radial direction. The air inlet 20 of the fan casing 19 faces the fan 24 from the axial direction of the fan 24, and the air outlet 21 of the fan casing 19. Faces the fan 24 from the radial direction of the fan 24.

  A lower end portion of the rear duct 25 is connected to the exhaust port 21 of the fan casing 19. The rear duct 25 has a cylindrical shape oriented in the vertical direction, and the upper end of the rear duct 25 is connected to the internal space of the water receiving tank 4 at the rear end of the water receiving tank 4. The rear duct 25, the fan casing 19, the main duct 17, the front duct 18, and the water receiving tank 4 constitute an annular circulation duct 26 that starts and ends at the internal space of the water receiving tank 4. When the fan motor 22 is operated in the closed state, the air in the water receiving tank 4 is sucked into the fan casing 19 from the front duct 18 through the main duct 17 based on the rotation of the fan 24 in a certain direction. The water is returned from the fan casing 19 to the water receiving tank 4 through the rear duct 25.

  A compressor (compressor) 27 is fixed inside the outer box 1. The compressor 27 is disposed outside the circulation duct 26 and has a discharge port for discharging the refrigerant and a suction port for sucking the refrigerant. The compressor 27 is driven by a compressor motor 28 (see FIG. 2), and the compressor motor 28 is constituted by a DC brushless motor capable of speed control.

  A condenser (condenser) 29 is fixed inside the main duct 17. The condenser 29 heats air and is configured by fixing each of a plurality of plate-like heating fins 31 in contact with the outer peripheral surface of one refrigerant pipe 30 that bends in a meandering manner. . The refrigerant pipe 30 of the condenser 29 is connected to the outlet of the compressor 27, and the refrigerant discharged from the outlet of the compressor 27 enters the refrigerant pipe 30 of the condenser 29 when the compressor motor 28 is operating.

  FIG. 1 schematically shows a drive control system of the drum motor 5, the fan motor 22, and the comp motor 28. The inverter circuit 34 is configured by connecting six IGBTs (switching elements) 35a to 35f in a three-phase bridge, and flywheel diodes 36a to 36f are connected between collectors and emitters of the IGBTs 35a to 35f. Yes. Each phase output terminal of the inverter circuit 34 is connected to each phase winding of the drum motor 5.

  The emitters of the IGBTs 35d, 35e, and 35f on the lower arm side are connected to the ground through shunt resistors 37u, 37v, and 37w. A common connection point between the emitters of the IGBTs 35d, 35e, and 35f and the shunt resistors 37u, 37v, and 37w is connected to an input terminal of a control circuit (microprocessor, microcomputer) 42A.

  Although not shown in the figure, the control circuit 42A includes an operational amplifier and the like, and a level shift circuit amplifies the terminal voltage of the shunt resistors 37u to 37w so that the output range of the amplified signal is within the positive side (for example, , 0 to + 3.3V). Further, the control circuit 42A has a function of performing overcurrent detection in order to prevent circuit destruction when the upper and lower arms of the inverter circuit 34 are short-circuited.

  An inverter circuit 38 and a shunt resistor 39 (u, v, w) configured similarly are arranged for the fan motor 22, and an inverter circuit 40 and a shunt resistor 41 (u) are arranged for the comp motor 28. , V, w) are arranged. The inverter circuits 38 and 40 are controlled by another control circuit 42B (microprocessor, microcomputer) and short-circuit control means), and the control circuits 42A and 42B are capable of bidirectional communication by serial communication. .

  A drive power supply circuit 43 is connected to the input side of the inverter circuits 34, 38, 40. The drive power supply circuit 43 is connected to a 100V AC power supply via a reactor (inductive reactor) 44 on one end side, and a full-wave rectifier circuit 45 configured by a diode bridge, and an output of the full-wave rectifier circuit 45 And two capacitors 46a and 46b connected in series on the side. A common connection point of the capacitors 46 a and 46 b is connected to one of the input terminals of the full-wave rectifier circuit 45. When the boosting operation using the reactor 44 described later is not performed, the driving power supply circuit 43 performs double voltage full-wave rectification of an AC power supply of 100 V and supplies a DC voltage of about 280 V to the inverter circuit 34 and the like.

  Another full-wave rectifier circuit 47 (short-circuit means), which is also formed of a diode bridge, is connected in parallel to the input terminal of the full-wave rectifier circuit 45, and between the output terminals of the full-wave rectifier circuit 47, , IGBT48 (short circuit means) is connected. The control circuit 42B performs on / off control of the IGBT 48.

  A series circuit of resistors 49a and 49b and a series circuit of resistors 50a and 50b are connected between the input terminals of the inverter circuits 34 and 38, respectively. It is connected. The control circuits 42A and 42B detect the drive power supply voltage input to the inverter circuits 34 and 38 by referring to the voltages at the common connection points.

  For the drum motor 5, a position sensor 51 (u, v, w) constituted by, for example, a Hall IC is arranged to detect the rotor position, and the sensor signal output from the position sensor 51 is Is provided to the control circuit 42A. Further, a current sensor 52 composed of, for example, a current transformer (CT) is inserted between the AC power source and the reactor 44, and a sensor signal output from the current sensor 52 is given to the control circuit 42B. .

The control circuits 42A and 42B detect currents flowing through the phase windings of the motors 5, 22, and 28, estimate the phase θ and rotational angular velocity ω of the secondary rotating magnetic field based on the current values, and An excitation current component Id and a torque current component Iq are obtained by performing orthogonal coordinate transformation and dq (direct-quadrature) coordinate transformation of the phase current. Then, when a speed command is given from the outside, the control circuits 42A and 42B generate current commands Idref and Iqref based on the estimated phase θ, rotational angular velocity ω, and current components Id and Iq, and generate the voltage commands Vd and Vq. When converted to, rectangular coordinate transformation and three-phase coordinate transformation are performed. Finally, a drive signal is generated as a PWM signal and is output to each phase winding of the motors 5, 22, and 28 via the inverter circuits 34, 38, and 40.
In the above configuration, the inverter circuit 34, the control circuits 42 </ b> A and 42 </ b> B, the drive power supply circuit 43, the reactor 44, the rectifier circuit 47, and the IGBT 48 constitute the drive device 60.

  Next, the operation of the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart schematically showing the process of the dehydration operation. First, acceleration is performed so as to gradually increase the rotational speed of the drum 7 (S1), and when the rotational speed reaches 1000 rpm (S2: YES), permission for boost control is set (S3). Thereafter, when the preset dehydration time ends (S4: YES), the permission of the boost control is cleared (S5). Then, when the brake is operated (S6) and the rotation of the drum 7 is stopped (S7: YES), the dehydrating operation is finished.

  FIG. 4 is a flowchart showing a boost control start / end determination process executed in response to an interrupt that occurs every 1 msec. In step S3 shown in FIG. 3, if the permission for boost control is set (S11: YES), it is determined whether or not the current status is “during boost control” (S12). If the boost control permission is not set (S11: NO), the status of “boost control in progress” is cleared (S16), and the interrupt process is terminated.

  If the current status is not “boosting control” in step S12 (NO), whether or not the AC power supply current at that time is equal to or greater than a preset value (boosting start value, control parameter) for starting boosting control. (S13). The boosting start value is about 6 A when the power consumption is 550 W, for example. Here, if it is equal to or higher than the boosting start value (YES), the status of “boosting control is in progress” is set (S14) to end the interrupt process, and if it is less than the boosting start value (NO), the interrupt process is ended as it is.

  If the current status is “in step-up control” at step S12 (YES), whether or not the AC power supply current at that time is equal to or lower than a preset value (step-up stop value) for stopping the step-up control. Is determined (S15). If it is equal to or lower than the boost stop value (YES), the process proceeds to step S16. If it exceeds the boost stop value (NO), the interrupt process is terminated.

  FIG. 5 is a flowchart showing a boost control start process that is executed in response to an interrupt that occurs every 1 msec as in the flow shown in FIG. 4. If the current status is “step-up control in progress” (S21: YES), the AC power supply current value at that time and the delay time from the zero cross point set according to either the power supply frequency 50 Hz or 60 Hz (for example, 1 (5 ms to 2 ms), a setting is made so that a short-circuit pulse is output during the first short-circuit operation (turning on the IGBT 48) (pulse width, for example, 0.6 ms) (S22). On the other hand, if the current status is not “in step-up control” (S21: NO), the output of the short-circuit pulse is cleared, that is, the short-circuit operation is not performed (S23) and the interrupt process is terminated.

  FIG. 6 is a flowchart showing the second and subsequent short-circuit operation processing executed every half cycle of the AC power supply. If a short-circuit pulse is currently being output (immediately after the first short-circuit pulse is output) (S31: YES), it is determined whether the rotational speed (control parameter) of the drum 7 is 1600 rpm or more (S32). If the number of revolutions has not reached 1600 rpm (NO), the number of short-circuit pulses is one, that is, only the first short-circuit pulse is output (S35), and the interrupt process is terminated.

  If the rotational speed is 1600 rpm or higher in step S32 (YES), it is determined whether or not the DC power supply voltage at that time is 295 V (an example of a target voltage) or higher (S33). If the DC power supply voltage is 295 V or higher (YES), the limit is set to “6” and the number of short-circuit pulses is increased by 1 (S34). When outputting a plurality of short-circuit pulses, the pulse output interval is set to, for example, 0.2 milliseconds. Further, the pulse width is reduced stepwise such that the width of the pulse output at the second and third times is, for example, 0.15 ms, and the width of the pulse output at the fourth to sixth times is, for example, 0.075 ms. In step S33, if the DC power supply voltage is less than 295 V (NO), the number of short-circuit pulses is decreased by 1 from the number of pulses output in the current AC half cycle (S36).

FIG. 7 shows an example of an actual power supply voltage / current waveform. The commercial AC power supply is rated at 50 Hz / 100 V, the DC power supply voltage is 304 V, and the number of short-circuit pulses is “4”. In this case, the decrease value of the current at the start of the second and subsequent short-circuit operations and the decrease amount with respect to the current peak value within the AC half cycle, and the increase value and the increase amount of the current accompanying the short-circuit operation are as follows: It has become.
Number of short-circuits Decrease value (decrease amount) Increase value (increase amount)
2nd 1.6A (10%) 3.4A (21%)
3rd 1.2A (7%) 3.0A (19%)
4th 1.2A (7%) 2.2A (14%)
These boosting control conditions are defined in claim 1, and when the short-circuit is performed a plurality of times within a half cycle of the AC power supply, the second and subsequent short-circuits are reached until the current peak value within the half cycle is reached. The amount of decrease in current at the start of operation is less than 30% of the current peak value in a half cycle, and the amount of increase in current accompanying the short circuit operation is less than 40% of the current peak value. It is controlled.

On the other hand, FIG. 8 shows a case where the boost control (the number of short-circuit pulses is “2”) in Patent Document 1 under the same power supply condition. The decrease value and decrease amount of current at the start of the second short-circuit operation, and the increase value and increase amount of current accompanying the short-circuit operation are as follows:
Number of short-circuits Decrease value (decrease amount) Increase value (increase amount)
The second 7.2A (40%) 15.2A (84%)
It is. It can be seen that the change in the waveform of the current flowing through the reactor 44 is more gradual in FIG. 7, and the DC power supply voltage after rectification is less varied in FIG.

  FIG. 9 and FIG. 10 show an example of the result of measuring the harmonic current value for the step-up control of this embodiment and Patent Document 1. FIG. In the case of Patent Document 1 shown in FIG. 10, the ninth, eleventh, thirteenth, and nineteenth harmonics exceed the regulation value (100% Limit, IEC standard for washing machines). On the other hand, in the case of the present embodiment shown in FIG. 9, all the harmonics up to the 40th order are below the regulation value.

Further, FIG. 11 shows a case where the pulse output interval is longer than that of the present embodiment shown in FIG. 9 and is set to 0.5 milliseconds (the number of short-circuit pulses is “3”). This is a substantially critical case where the boost control conditions of the present embodiment described above are maintained.
Number of short-circuits Decrease value (decrease amount) Increase value (increase amount)
2nd 2.5A (17%) 4.0A (27%)
3rd 2.0A (13%) 6.0A (40%)
As a result, as shown in FIG. 12, only the 23rd harmonic current exceeds the regulation value.

  As described above, according to the present embodiment, the control circuit 42B causes the IGBT 48 to switch between the input terminals of the rectifier circuit 45 between the zero-cross timings of the voltage waveform of the AC power supply according to the change of the control parameter when performing the dehydration operation. Change the number of shorts. When the short-circuit operation is performed a plurality of times within a half cycle of the AC power supply, the current decrease amount at the time of starting the second and subsequent short-circuit operations until the current peak value within the half cycle is reached. The peak value is controlled each time a current change is caused by a short circuit by controlling so that the increase in current accompanying the short circuit operation is less than 40% of the current peak value so as to be less than 30% of the peak value. Increase. By performing boost control in this way, a high boost effect can be obtained and an increase in harmonic current can be suppressed.

Further, the control circuit 42B detects the DC voltage output from the rectifier circuit 45 and changes the number of short circuits so that the DC voltage maintains the target voltage, so that the boost control can be stabilized. As a result, it is possible to avoid an event such as a circuit component being damaged due to an excessively high voltage temporarily generated, or a reduction in the rotational speed of the drum 7 due to insufficient boosting.
Furthermore, the control circuit 42B detects the number of rotations of the motor 5 that performs the dehydration operation, and changes the number of short circuits in a region where the number of rotations is equal to or greater than a threshold value. As a result, a high voltage required in a region where the rotational speed is high can be obtained, and the boost control can be executed efficiently.

(Second Embodiment)
FIG. 13 shows a second embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different parts will be described below. In the second embodiment, in step S13 shown in FIG. 4, the delay time of the short-circuit pulse output for the first time is changed according to the alternating current value at that time, and the short-circuit time (pulse width) by each pulse is also changed. The delay time is changed from a current value of 6 A to 0.6 A at a maximum exceeding 14.4 A, from 2.152 msec when the power supply frequency is 50 Hz, to 2.490 msec in increments of 0.024 msec. Further, the width of the short-circuit pulse is changed from 0.579 msec to 0.647 msec in steps of 0.0184 msec (current value of 10.2 A or more is the same value). The pulse widths output in the second to fourth times are 1/3, 1/4, and 1/7 in the first time, respectively, and the pulse widths after the fifth time are the same as those in the fourth time.

  As described above, according to the second embodiment, the control circuit 42B determines the short-circuit time according to the current value of the AC power supply current, so that the harmonic reduction effect can be optimized according to the current value. become.

(Third embodiment)
FIG. 14 shows a third embodiment. In the first embodiment, control is performed so as to increment and decrement the number of short-circuit pulses output according to the flowchart shown in FIG. On the other hand, in the third embodiment, processing using the control system shown in FIG. 14 (function blocks formed mainly by software processing by the control circuit 42B) is executed every half cycle of alternating current. The voltage control unit 61 sets the target voltage to, for example, 295V. The voltage detector 62 includes the resistance elements 50a and 50b shown in FIG. 1 and an A / D converter in the control circuit 42B, and detects the actual DC voltage value. The subtractor 63 calculates the difference between the target voltage and the actual voltage and inputs the difference to the voltage PI unit 64.

  The voltage PI unit 64 performs a PI (Proportional-Integral) control calculation on the input differential voltage, and outputs a short-circuit time width as the calculation result. For example, the proportional term of the PI gain is set to 0.05% / V, the integral term is set to 10% / V · sec, etc., and the range of the short-circuit time width is set to 0 to 20% of the AC half cycle. The time width → pulse number conversion unit 65 outputs the number of short-circuit pulses corresponding to the input short-circuit time width. The short-circuit pulse output unit 66 generates a gate drive signal corresponding to the number of input short-circuit pulses and outputs it to the gate of the IGBT 48.

  As described above, according to the third embodiment, the control circuit 42B determines the number of short-circuit pulses by performing PI control on the difference between the target voltage and the actual DC power supply voltage. As a result, the boost control can be performed so that the actual DC power supply voltage approximates the target voltage.

(Other embodiments)
The control circuits 42A and 42B may be integrated into one control circuit.
The pulse width when the short circuit is performed by the IGBT 48 and the delay time from the zero cross point may be appropriately changed.
The semiconductor switching element is not limited to the IGBT, and a bipolar transistor or a MOSFET may be used.
The setting of the threshold values relating to the rotation speed, voltage, current, and power is an example, and may be changed as appropriate according to individual design.
Specific numerical values such as the delay time of the initial short-circuit pulse, the output interval of each pulse, and the pulse width are examples, and may be appropriately changed according to the individual design.
You may apply to the washing machine which does not have a drying function.

  Although several embodiments of the present invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawing, 5 is a drum motor, 7 is a drum, 22 is a fan motor, 27 is a compressor, 28 is a compressor motor, 42B is a control circuit (short-circuit control means), 34, 38 and 40 are inverter circuits, and 43 is a drive power supply. Reference numeral 44 denotes a reactor, 45 denotes a full-wave rectifier circuit (rectifier circuit), 47 denotes a full-wave rectifier circuit (short-circuit means), 48 denotes an IGBT (short-circuit means), and 60 denotes a drive device.

Claims (5)

A rectifier circuit connected to an AC power source via a reactor;
Short-circuit means for short-circuiting between the input terminals of the rectifier circuit;
An inverter circuit that is connected to the output side of the rectifier circuit to convert DC power into AC power and drives a motor that generates at least rotational driving force for performing dehydration operation;
In accordance with a change in control parameters when performing the dehydration operation, short circuit control means for changing the number of times the input terminals are short-circuited between zero-cross timings of the voltage waveform of the AC power supply by the short circuit means,
The short-circuit control means controls to perform in the first half of the half cycle when the short-circuit is performed a plurality of times within a half cycle of the AC power supply, and causes a current peak value each time a current change occurs due to a short circuit. Increase the motor drive of the washing machine.   The motor driving device for a washing machine according to claim 1, wherein the short-circuit control means detects a DC voltage output from the rectifier circuit and changes the number of short-circuits so that the DC voltage maintains a target voltage.   The motor driving device for a washing machine according to claim 1 or 2, wherein the short-circuit control means detects the number of rotations of a motor that performs the dehydration operation and changes the number of short-circuits in a region where the number of rotations is equal to or greater than a threshold value.   The motor driving device for a washing machine according to any one of claims 1 to 3, wherein the short-circuit control means detects an alternating current and determines a short-circuit time according to the current value. When the short-circuit control means performs the short-circuit a plurality of times within a half cycle of the AC power supply, the current decreases at the time of starting the second and subsequent short-circuit operations until reaching the current peak value within the half cycle. Each time a current change is caused by a short circuit, the amount is controlled to be less than 30% of the current peak value and the increase amount of the current accompanying the short circuit operation is less than 40% of the current peak value. The motor driving device for a washing machine according to any one of claims 1 to 4, wherein the peak value is increased.

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