JP2017034897A - Motor controller and washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid influence of switching noise on A/D conversion even when a plurality of PWM control periods are different.SOLUTION: A motor controller for a washing machine, according to an embodiment, includes a plurality of motor drive circuits and a plurality of control circuits for individually performing PWM control of the respective motor drive circuits, the motor drive circuits and control circuits being arranged on a single circuit board. A current of each motor is detected by the control circuit by performing A/D conversion on a terminal voltage of a shunt resistor disposed on a corresponding motor drive circuit. At least any one or more control circuits change a phase of a PWM carrier in order to avoid agreement between timing of switching operation by each motor drive circuit and timing of execution of A/D conversion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device in which a plurality of motor drive circuits and a plurality of control circuits for performing PWM control of the respective motor drive circuits are arranged on the same circuit board, and a washing machine including the device. .

  Conventionally, in a configuration where multiple motors are driven by PWM (Pulse Width Modulation) control using a single control circuit, the operating current on the other side becomes noise and affects the detected current value on one side. Operation (for example, error display or generation of abnormal noise) may occur. As a technique for preventing such malfunction, there is, for example, Patent Document 1. In Patent Document 1, synchronization is performed at the peak or bottom of the carrier signal amplitude so that the PWM cycles of the plurality of inverter circuits that drive the plurality of motors are the same or an integer multiple. The timing of A / D conversion to detect the phase current of each motor is also synchronized with the PWM cycle, thereby avoiding the other PWM switching from affecting the current detection performed by one control circuit as noise. ing.

Japanese Patent No. 4682727

  However, as in Patent Document 1, in order to synchronize a plurality of PWM control cycles, it is necessary to use a common clock signal oscillator for each. Unlike Patent Document 1, in a configuration in which a plurality of motors are PWM-controlled by a plurality of control circuits (for example, a microcomputer), a clock oscillator is mounted on each control circuit, so the configuration of Patent Document 1 is applied. Is difficult.

  Similarly to Patent Document 1, when a plurality of motors are controlled by a single control circuit, it is necessary to provide a number of output pins in the control circuit and to include a plurality of PWM timers and A / D converters. The options will be limited. Further, with respect to the wiring pattern of the substrate, it is desirable that the ground is concentrated at one point if there is one control circuit. However, in this case, if the number of switching elements to be used increases, the wiring distance to the ground point must be increased, and malfunction due to noise generated in the switching operation is likely to occur.

  Therefore, there are provided a motor control device capable of avoiding the influence of switching noise on A / D conversion even when a plurality of PWM control cycles are different, and a washing machine including the device.

  According to the motor control device of the embodiment, a plurality of motor drive circuits and a plurality of control circuits that respectively PWM control each motor drive circuit are arranged on the same circuit board, and the control circuit Is detected by A / D converting the terminal voltage of the shunt resistor arranged in the corresponding motor drive circuit, the timing of the switching operation by each motor drive circuit, the execution timing of the A / D conversion, and In order to avoid the coincidence, at least one of the control circuits changes the phase of the PWM carrier.

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 The flowchart which shows the content of the process by the control circuit about the part which concerns on the summary of this embodiment Timing chart explaining PWM carrier phase adjustment processing The figure which shows the actual current waveform and its A / D conversion value of a drum motor, and the actual current waveform of a compressor motor The figure which adds the waveform which extracted the noise component about the actual current waveform of the drum motor shown in FIG. FIG. 5 equivalent diagram showing the result of executing the processing shown in FIG. Timing chart explaining operation of Patent Document 1 The figure which shows the ground wiring pattern in patent document 1 as a model The figure which shows the ground wiring pattern in this embodiment modelly The flowchart which is 2nd Embodiment and shows the interruption process performed at the detection timing of the zero crossing point of commercial AC power supply voltage

(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 (motor drive circuit) 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. 36f is connected. 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 (motor drive circuit) and a shunt resistor 39 (u, v, w) configured similarly are arranged for the fan motor 22, and an inverter circuit 40 ( A motor driving circuit) and a shunt resistor 41 (u, 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. .

  Ceramic or crystal oscillators 53A and 53B are connected to the control circuits 42A and 42B, respectively, and these are connected to an oscillation circuit built in the control circuits 42A and 42B. As an example, the control circuit 42A internally multiplies the 12.5 MHz oscillation signal by 8 and operates with a 100 MHz clock, and the control circuit 42B multiplies the 8 MHz oscillation signal by 8 and operates with a 64 MHz clock. ing.

  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, which is similarly formed of a diode bridge, is connected in parallel to the input terminal of the full-wave rectifier circuit 45, and an IGBT 48 is connected between the output terminals of the full-wave rectifier circuit 47. Has been. The control circuit 42B performs on / off control of the IGBT 48. Further, a zero-cross point detection circuit 54 for detecting a zero-cross point of the commercial AC power supply voltage is connected to an input terminal of the full-wave rectifier circuit 45. An output terminal of the zero-cross point detection circuit 54 is connected to the control circuits 42A and 42B. Connected to the interrupt signal input terminal.

  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. The common connection point is connected to the input terminals of the control circuits 42A and 42B. 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. At least the inverter circuits 34, 38 and 40 and the control circuits 42A and 42B are mounted on the same circuit board.

  Next, the operation of the present embodiment will be described with reference to FIGS. FIG. 8 shows a technique disclosed in Patent Document 1. A / D conversion is performed by synchronizing the PWM output period and A / D conversion timing in a plurality of inverter circuits (first and second motor circuits). The effect of noise on the value is reduced. That is, the timing at which the control circuit performs A / D conversion and the timing at which the IGBTs constituting the inverter circuit are switched based on the PWM signal are avoided from overlapping.

  FIG. 5 shows that the drum motor 5 (DD motor in the figure) and the comp motor 28 are connected to the inverter circuits 34 and 40 by the two control circuits 42A and 42B which are the configuration of this embodiment under the same conditions as FIG. An A / D conversion value noise waveform on the drum motor 5 side when driven is shown. The PWM carrier wave is 15.6 kHz on the dehydration motor side and 7.8 kHz on the comp motor 28 side, and is in a 2: 1 relationship. However, since the oscillators 53A and 53B connected to the control circuits 42A and 42B have inherent errors, the mutual relationship between the PWM periods is gradually shifted, resulting in periodic A / D conversion value noise. It captures the period when the phenomenon of increasing is occurring.

  Further, as shown in FIG. 6, the noise amount can be calculated by calculating the difference from the previous A / D conversion value, thereby erasing the motor current value and extracting only the noise component (noise). Extracted waveform). This makes it possible to determine the amount of noise.

  FIG. 3 is a flowchart showing the contents of the processing by the control circuit 42A for the portion according to the gist of the present embodiment, and is interrupt processing executed every 128 μs. First, the control circuit 42A samples each phase current of the drum motor 5 by A / D conversion (S1), and performs vector control processing based on the sampled phase current (S2).

  Next, for example, a difference value between the current sampled for the U-phase current and the current sampled last time is calculated (S3), and the absolute value of the difference value is added using, for example, an accumulator (S4). If the number of additions does not reach 20 (S5; NO), the process is terminated and the process returns to the main routine (not shown).

  When the number of additions in step S4 reaches 20 (S5; YES), an average value is calculated by dividing the accumulated addition value by the number of additions (S6). Then, on the condition that 50 ms has passed since the previous determination, it is determined whether or not the average value is 0.3 A or more (S7). Here, the condition that “50 ms has passed since the last determination” is, for example, that the period of noise occurring in FIG. 6 is about 200 ms. On the other hand, if the occurrence of noise again is detected within a short time such as 50 ms from the previous determination, the possibility of erroneous detection is extremely high.

  If the average value is less than 0.3 A in step S7 (NO), the process is terminated and the process returns to the main routine. On the other hand, if the average value is 0.3 A or more (YES), the output of the PWM signal is temporarily stopped (S8), the phase of the PWM carrier is shifted by a half cycle, and the output of the PWM signal is resumed (S9). The processing for shifting the phase of the PWM carrier here by a half cycle is specifically performed by writing a counter value corresponding to a half cycle to the counter for the control circuit 42A to output the PWM carrier.

  With the above processing, the switching operation in the inverter circuit 40 based on the PWM signal shown on the upper side of FIG. 4 affects the A / D conversion processing of the current performed by the control circuit 42A shown on the lower side of FIG. 4 as noise. When the state is reached (S7; YES), the control circuit 42A temporarily stops the output of the PWM signal (S8), shifts the phase of the PWM carrier by a half cycle, and restarts the output (S9). Thereby, the timing at which the control circuit 42A performs A / D conversion and the timing at which the switching operation is performed on the inverter circuit 40 side do not overlap, and the state affecting the A / D conversion processing is eliminated. As a result, as shown in FIG. 7, the amplitude of the noise extraction waveform is reduced.

  Here, in FIG. 9, as in Patent Document 1, an IPM (Intelligent Power Module: 1, 2), which is a drive circuit corresponding to two motors (1, 2), is controlled by one microcomputer (control circuit). Regarding the configuration, the ground wiring pattern around the shunt resistor is shown as a model. In this case, if all the ground wirings are concentrated at one point, the wirings become long, so that the potential difference from the ground point becomes large, and the possibility of malfunctioning becomes higher.

  On the other hand, FIG. 10 shows a case where control is performed by two microcomputers as in this embodiment, and since the respective grounds are independent (circle numbers 1 and 2 in the figure), the area around the shunt resistor is The ground wiring is shortened, the inductance is reduced, and the possibility of malfunctions is further reduced. In addition, noise generated in that portion during switching is also reduced.

  As described above, according to the present embodiment, the inverter circuits 34, 38 and 40 and the control circuits 42A and 42B are arranged on the same circuit board, and the control circuits 42A and 42B are connected to the motors 5, 22 and 28, respectively. Is detected by A / D converting the terminal voltages of the shunt resistors 37, 39 and 41 arranged in the corresponding inverter circuits 34, 38 and 40, respectively. The control circuit 42A changes the phase of the PWM carrier in order to avoid the coincidence of the timing at which the inverter circuit 40 performs the switching operation and the timing at which the control circuit 42A performs the A / D conversion.

  Therefore, even if the PWM cycles of the control circuits 42A and 42B are different, mutual interference due to switching noise can be reduced. Further, since the A / D conversion grounds respectively executed by the control circuits 42A and 42B can be separated, the ground wiring length can be shortened, noise generation at the time of switching can be reduced, and the inverter circuits 34, 38 and 40 In addition, it is possible to prevent malfunction of the IPM including these gate drive circuit and protection circuit. In addition, since the microcomputers used for the control circuits 42A and 42B may be small, the number of component options at the time of design increases.

(Second Embodiment)
Hereinafter, the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof will be omitted, and different parts will be described. FIG. 11 shows an interrupt process executed each time the falling edge of the detection signal is input to the control circuit 42A by detecting the zero cross point of the commercial AC power supply voltage by the zero cross point detection circuit 54 shown in FIG. is there. When the control circuit 42A executes the process for the first time (S11; YES), the control circuit 42A activates a built-in clock frequency dividing timer to start measuring the interrupt interval (S22), ends the process, and returns. To do.

  When the interrupt process is the second or later (S11; NO), it is subsequently determined whether or not the process has reached the tenth time (S12), and if it has not reached the tenth time (NO), the process is terminated. Return. When the interrupt process reaches the 10th time (YES), the measurement is finished (S13), and the timer value is read (S14). Then, it is determined whether or not the timer value is equal to or greater than a value corresponding to 183 ms (S15). If the timer value is equal to or greater than a value corresponding to 183 ms, it is determined that the AC power supply frequency is in a region of 50 Hz (S16). In this case, it is further determined whether or not the timer value is in the range of 195 ms to 205 ms (S17). If it is within the range (YES), the cycle of the PWM carrier generated from the clock of the control circuit 42A is corrected (S18). ).

  In step S15, if the timer value is less than the value corresponding to 183 ms (NO), it is determined that the AC power supply frequency is in the area of 60 Hz (S19). In this case, it is further determined whether or not the timer value is in the range of 162 ms to 173 ms (S20). If it is within the range (YES), the process proceeds to step S18. Note that the determinations in steps S19 and S20 correspond to monitoring of the commercial AC power supply cycle.

The correction value (correction coefficient) in step S18 is determined as follows for each district.
50 Hz area: correction value = (timer value) / 200 ms
60 Hz area: correction value = (timer value) / 167 ms
If (NO) is determined in steps S17 and S20, the correction value is set to “1” (S21). Then, the carrier period is adjusted by multiplying the correction value thus determined by the timer value for setting the carrier wave period.

  That is, since the timer value obtained in step S14 is a value corresponding to 10 times the AC power supply period, accurate values corresponding to 50 Hz and 60 Hz are values corresponding to 200 ms and 167 ms, respectively. Therefore, if the timer value is accurate, the correction value in step S18 is “1” and is not substantially adjusted. If there is an error, the timer value is adjusted to a value other than “1”.

  Further, the case of determining “NO” in steps S17 and S20 is a state in which the count value of the AC power supply frequency by the timer exceeds the allowable range on which the adjustment is performed. Therefore, the correction value is set to “1” in order to avoid making an adjustment based on such a result.

  As described above, according to the second embodiment, the control circuit 42A adjusts the period of the PWM carrier using the commercial AC power supply period. That is, since the commercial AC power supply cycle is relatively stable, the carrier cycle can be accurately adjusted based on the cycle. In this case, the control circuit 42A monitors the commercial AC power supply cycle, and stops the adjustment when it is determined that the cycle exceeds the allowable range. Thereby, when the commercial AC power supply period monitored by the control circuit 42A exceeds the allowable range, it is possible to avoid making an incorrect adjustment.

(Other embodiments)
The control circuit 42B side may change the phase of the PWM carrier.
The time for resuming the output of the PWM signal when changing the phase of the PWM carrier is not limited to ½ of the carrier period, and may be appropriately changed according to the individual design.
The semiconductor switching element is not limited to the IGBT, and a bipolar transistor or a MOSFET may be used.
You may apply to the washing machine which does not have a drying function. Moreover, you may apply to motors other than a washing machine.

The operation clock frequency of the control circuit, the interrupt processing cycle, and the like are examples, and may be appropriately changed according to individual designs.
The setting of the number of times in step S5 for obtaining the average value in step S6 of the first embodiment may be appropriately changed.
Moreover, what is necessary is just to change the timer value of step S15, S17, S20 in 2nd Embodiment according to the setting of the frequency | count in step S12, and how much the allowable range is set.
When three or more control circuits perform PWM control, two or more control circuits may change the phase of the PWM carrier in order to avoid the influence of noise.

  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 drawings, 5 is a drum motor, 7 is a drum, 22 is a fan motor, 27 is a compressor, 28 is a compressor motor, 42 is a control circuit, 34, 38 and 40 are inverter circuits (motor drive circuits), and 60 is a drive device. Show.

Claims (6)

A plurality of motor drive circuits and a plurality of control circuits for PWM controlling each motor drive circuit are arranged on the same circuit board,
The control circuit detects the current of each motor by A / D converting the terminal voltage of the shunt resistor arranged in the corresponding motor drive circuit,
A motor control device in which at least one of the control circuits changes the phase of the PWM carrier in order to avoid that the timing of the switching operation by each motor drive circuit coincides with the execution timing of the A / D conversion. .   The motor control device according to claim 1, wherein the control circuit changes the phase of the PWM carrier based on at least one of the current detection values.   2. The motor control device according to claim 1, wherein, when the output of the PWM signal is stopped, the control circuit changes the phase of the PWM carrier by restarting the output of the PWM signal after a half of the carrier period has elapsed.   The motor control device according to claim 1, wherein the control circuit adjusts a carrier cycle by using a commercial AC power supply cycle.   The motor control device according to claim 4, wherein the control circuit monitors a commercial AC power supply cycle and stops the adjustment when it is determined that the cycle exceeds an allowable range.   A washing machine comprising the plurality of motors and the motor control device according to any one of claims 1 to 5.

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