JP6713824B2 - Washing machine motor controller - Google Patents

Description

Embodiments of the present invention relate to a device that controls a three-phase permanent magnet motor that generates a rotational driving force for performing a washing operation.

Conventionally, various configurations have been proposed for detecting a disconnection abnormality of a motor used in a washing machine. For example, in Patent Document 1, (1) detection by temperature, (2) determination by comparing maximum value and average value of input current of inverter circuit, (3) detection of current of switching element that is ON, (4) motor Various methods have been disclosed, such as comparing the number of revolutions with the ripple current.

However, these methods have the following problems. (1) is not reliable and may cause false detection when a large amount of laundry is put in, and (2) is also uncertain, and when the load fluctuation is large, the difference between the average and maximum values is normal. Is likely to be falsely detected. In the case of (3), a large number of current detection elements are required, and a high-speed amplifier and A/D converter are also required to read the signal of the current detection element that the control circuit turns ON/OFF at high speed, which is expensive. Also in (4), the current detector is expensive, and there is a risk of false detection when the rotational load changes.
Further, as other configurations, there are those disclosed in Patent Documents 2 and 3.

JP, 10-145960, A JP-A-6-205599 Japanese Patent Laid-Open No. 2009-61164

In Patent Document 2, in the motor inverter applied to the air conditioner, the switching elements are sequentially turned on to determine the disconnection phase, but a current transformer is arranged on the AC side to detect the motor current. It is an expensive structure. In addition, Patent Document 3 also uses a high-speed microcomputer and three current sensors for performing vector control calculation, and is also an expensive configuration.

Therefore, there is provided a washing machine motor control device capable of more reliably detecting disconnection without using expensive components.

A control device for a washing machine motor according to an embodiment includes a three-phase permanent magnet motor that generates a rotational driving force for performing a washing operation, an inverter circuit that drives this motor, and a lower switching that configures this inverter circuit. In a process of detecting a current detection resistor inserted between an element and a ground, a position sensor that detects a rotor rotation position of the motor and outputs a sensor signal, and a rotation abnormality of the motor based on the sensor signal. When detecting a disconnection abnormality by A/D converting the terminal voltage of the current detection resistor and comparing it with a reference value, the current detected by the current detection resistor is the winding of any one phase of the motor. The switching state of the inverter circuit is controlled so that the current is concentrated in the current, and the switching state is changed at least once to change the phase of the current detected by the current detection resistor. And an abnormality detection unit that refers to the current generation state of.

Further, the control device for a washing machine motor according to the embodiment includes a three-phase permanent magnet type motor that generates a rotational driving force for performing a washing operation, an inverter circuit that drives the motor, and a lower part that configures the inverter circuit. A disconnection abnormality is detected in the process of detecting an overcurrent by A/D converting the current detection resistor inserted between the side switching element and the ground and the terminal voltage of this current detection resistor and comparing it with a reference value. At this time, the switching state of the inverter circuit is controlled so that the current detected by the current detection resistor becomes a current that is concentrated and conducted in any one-phase winding of the motor, and the switching state is set to 1 An abnormality detection unit that changes the phase of the current detected by the current detection resistor by changing the current more than once and refers to the current generation state of all the phases.

It is 1st Embodiment and is a flowchart which shows the process which detects an overcurrent abnormality and a disconnection abnormality. The figure which shows the switching pattern for detecting disconnection (the 1) The figure which shows the switching pattern for detecting disconnection (the 2) The figure which shows the switching pattern for performing disconnection detection (Part 3) Waveform diagram showing each switching pattern in two-phase modulation Flowchart showing voltage determination processing in voltage/phase control Diagram showing the table that determines the voltage command DUTY according to the overcurrent value The figure explaining an example of a voltage command. Diagram showing the drive control system of the motor Vertical side view showing the overall structure of a fully automatic washing machine It is 2nd Embodiment and is a flowchart which shows the process which detects an overcurrent abnormality and a disconnection abnormality. Diagram showing switching pattern for detecting disconnection The figure which shows an example of the electric current A/D conversion value change according to the presence or absence of disconnection detection. It is 3rd Embodiment and is a flowchart which shows the process which detects an overcurrent abnormality and a disconnection abnormality.

(First embodiment)
Hereinafter, a first embodiment applied to a vertical type fully automatic washing machine will be described with reference to FIGS. 1 to 10. FIG. 10 is a vertical cross-sectional view showing the overall configuration of the fully automatic washing machine 1. In the outer box 2 having a rectangular shape as a whole, only one of the four water receiving tanks 3 is elastically supported via the illustrated vibration isolation mechanism 4. In this case, the vibration-proof mechanism 4 includes a suspension rod 4a whose upper end is locked upward in the outer case 2 and a vibration damping damper 4b attached to the other end of the suspension rod 4a. Has been done. The water receiving tub 3 is elastically supported through the vibration isolating mechanism 4 to prevent the vibration generated during the washing operation from being transmitted to the outer box 2.

A rotating tub 5 serving as a washing tub and a dehydrating tub is provided in the water receiving tub 3, and an agitator 6 is provided at an inner bottom portion of the rotating tub 5. The rotary tank 5 is composed of a tank body 5a, an inner cylinder 5b provided inside the tank body 5a, and a balance ring 5c provided at the upper ends of these. Then, when the rotary tank 5 is rotated, the water inside is pumped up by the rotational centrifugal force and discharged into the water receiving tank 3 through the dehydration hole 5d in the upper part of the tank body 5a.

Further, a water passage 7 is formed at the bottom of the rotary tank 5, and the water passage 7 is connected to the drainage port 8 through the drainage passage 7a. A drainage channel 10 having a drainage valve 9 is connected to the drainage port 8. Therefore, when water is supplied to the rotary tank 5 with the drain valve 9 closed, water is stored in the rotary tank 5, and when the drain valve 9 is opened, the water in the rotary tank 5 is drained to the drain passage 7a, the drain port 8 and It is discharged through the drainage channel 10. An auxiliary drainage port 8a is formed at the bottom of the water receiving tank 3, and the auxiliary drainage port 8a is connected to the drainage channel 10 by bypassing the drainage valve 9 via a connecting hose (not shown). When 5 rotates, the water discharged into the water receiving tank 3 is discharged from the upper part.

Further, a mechanism housing 11 is attached to the outer bottom portion of the water receiving tank 3, and a hollow tank shaft 12 is rotatably provided on the mechanism housing 11 and the tank shaft 12 rotates. The tank 5 is connected. A stirring shaft 13 is rotatably provided inside the tank shaft 12, and a stirring body 6 is connected to an upper end portion of the stirring shaft 13. The lower end of the stirring shaft 13 is connected to the rotor 14a of the outer rotor type DC brushless motor 14. The motor 14 directly drives the stirring body 6 in normal and reverse directions during washing. The DC brushless motor 14 is a permanent magnet type motor, and will be simply referred to as a motor hereinafter.

In addition, the motor 14 directly drives the rotary tank 5 and the stirring body 6 in one direction while the tank shaft 2 and the stirring shaft 13 are connected by a clutch (not shown) during dehydration. Therefore, in the present embodiment, the rotation speed of the motor 14 is the same as that of the stirring body 6 at the time of washing, and is the same as that of the rotary tank 5 and the stirring body 6 at the time of dehydration, that is, a so-called direct drive system is adopted. .. The motor 14 is configured to increase the output torque in the low speed region.

FIG. 9 is a functional block diagram showing a drive control system of the motor 14. The inverter circuit 21 is configured by connecting six IGBTs 22a to 22f in a three-phase bridge connection, and flywheel diodes 23a to 23f are connected between collectors and emitters of the IGBTs 22a to 22f. The IGBT 22 corresponds to a semiconductor switching element. The emitters of the lower arm side IGBTs 22d, 22e, 22f are connected to the ground via a shunt resistor 24. The shunt resistor 24 corresponds to a current detection resistor. The common connection point between the emitters of the IGBTs 22d, 22e, 22f and the shunt resistor 24 is connected to the ground via the resistance element 25 and the capacitor 26. The common connection point of the resistance element 25 and the capacitor 26 is connected to the input terminal of the peak hold circuit 27 and the inverting input terminal of the comparator 28.

The peak hold circuit 27 is configured by using a comparator 29, and this comparator 29 is built in the IC 30 together with the comparator 28. That is, the IC 30 includes the comparator 2 circuit. The outputs of these comparators 28 and 29 are of the open collector type.

The non-inverting input terminal of the comparator 29 is connected to the common connection point of the resistance element 25 and the capacitor 26 via the resistance element 25+, and is also connected to the ground via the capacitor 32. These form an RC filter. The inverting input terminal of the comparator 29 is connected to the ground via the resistance elements 33 and 34. The output terminal of the comparator 29 is pulled up to the 5V power source via the resistance element 35 and connected to the ground via the diode 36 and the capacitor 37. The cathode of the diode 36 is connected to the common connection point of the resistance elements 33 and 34 via the resistance element 38, and is also connected to the input terminal of the control circuit 39.

A series circuit of the resistance elements 40 and 41 is connected between the 5V power source and the ground, and a common connection point of both is connected to the non-inverting input terminal of the comparator 28. The output terminal of the comparator 28 is pulled up to the 5V power source via the resistance element 42, connected to the ground via the capacitor 43, and further connected to the input terminal of the control circuit 39. The output signal of the comparator 28 becomes an emergency stop signal based on overcurrent detection, and the control circuit 39 stops the output of the PWM signal to the inverter circuit 21 when the emergency stop signal is input. The control circuit 39 corresponds to an abnormality detection unit and a PWM control unit.

The motor 14 is provided with a position sensor 44 (A, B) for detecting the rotational position of the rotor. The position sensor 44 is composed of, for example, a Hall IC, and outputs two-phase signals whose phases are different by 90 degrees. The sensor signal output from the position sensor 44A, that is, the rising edge of the position signal corresponds to the electrical angle of 0 degree of the rotor 14a. The output terminals of the sensor signal are connected to the input terminals of the control circuit 39 via the NOT gates 45A and 45B, respectively, and the output terminals of the NOT gates 45A and 45B are connected to the ground via the capacitors 46A and 46B.

A drive power supply circuit 47 is connected to the input side of the inverter circuit 21. The driving power supply circuit 47 double-voltage full-wave rectifies an AC power supply 48 of 100V by a full-wave rectification circuit 49 composed of a diode bridge and two capacitors 50a and 50b connected in series to obtain a DC voltage of about 280V. Is supplied to the inverter circuit 21. Each phase output terminal of the inverter circuit 21 is connected to each phase winding 14u, 14v, 14w of the motor 14.

The first power supply circuit 51 supplies the control circuit 39 and the drive circuit 52 when the driving power supply of about 280V supplied to the inverter circuit 21 is stepped down to generate a 15V power supply. The second power supply circuit 53 is a three-terminal regulator that steps down the driving power supply to generate a 5V control power supply and supplies it to the control circuit 39. The high voltage driver circuit 54 is arranged to drive the upper arm side IGBTs 22 a to 22 c in the inverter circuit 21.

A series circuit of resistance elements 55a and 55b is connected between the output terminal of the driving power supply circuit 47, that is, the positive side DC bus of the inverter circuit 21 and the ground. It is connected to the input terminal of the circuit 39. The control circuit 39 is composed of, for example, an 8-bit microcomputer, and generates three-phase upper and lower PWM signals whose voltage ratio changes in a sinusoidal manner by performing voltage/phase control. Then, those PWW signals are output to the gates of the respective IGBTs 22a to 22f forming the inverter circuit 21 via the drive circuit 52 and the high voltage driver circuit 54 for the upper side. Details of the sine wave driving method are disclosed in, for example, JP-A-2014-39724.

Next, the operation of this embodiment will be described with reference to FIGS. 1 to 8. The control circuit 39 generates a PWM signal based on the sensor signals of the position sensors 44A and 44B synchronized with the rotor rotation position of the motor 14. The inverter circuit 21 generates a three-phase AC voltage whose voltage and frequency are controlled by the PWM signal from a DC power supply of about 180V to 300V. At that time, the control circuit 39 detects the voltage divided by the resistance elements 55a and 55b in order to eliminate the influence of the output fluctuation due to the ripple of the DC power supply voltage, and outputs by adding the voltage component for canceling the ripple.

The control circuit 39 causes the motor 14 to perform a normal/reverse operation in about 1 second during the washing operation, and outputs a PWM signal with a fixed duty so that the rotation speed thereof is set to about 100 rpm to 150 rpm. At this time, the rotation load of the motor 14 is heavy and the number of rotations becomes lower than the control target value, or the current increases significantly when the motor 14 is locked. As a result, problems such as demagnetization of the motor 14 and heat generation of the IGBT 22 may occur. In order to prevent such a situation, the control circuit 39 detects the output of the peak hold circuit 27 every 1 msec, and when it detects a current value of 7.5 A or more, the PWM duty is temporarily reduced by proportional control.

The peak hold time is adjusted by the output side capacitor 37 of the peak hold circuit 27 and the discharging resistance elements 38 and 34. In one rotation of the motor 14, the current peak occurs 144 times, for example. Therefore, the peak hold time is adjusted so that the level can be held between the current peaks so that the control circuit 39 can reliably read the A/D converted current value. Also, the feedback resistance ratio is adjusted so as to maximize the amplification factor of the peak hold circuit 27 in consideration of the current value and the input range of the A/D converter. This reduces the influence of noise.

2 to 5 show switching patterns for detecting disconnection after the rotation of the motor 14 has stopped due to an abnormality such as an overload, disconnection of the power line or position sensor line, or failure of the IGBT 22 while the motor 14 is being driven. .. In the pattern (A) shown in FIG. 2, the U-phase and V-phase upper IGBTs 22a and 22b are turned on with the same PWM duty to generate the same voltage. Since the W-phase turns on the lower IGBT 22f, the same current is applied to the U-phase and V-phase windings 14u and 14v of the motor 14, and the combined current flows through the W-phase winding 14w to the shunt resistor 24. .. In the pattern (B) shown in FIG. 3, current is conducted from the upper U-phase and W-phase to the lower V-phase, and in the pattern (C) shown in FIG. 4, the upper V-phase and W-phase are lower than the lower U-phase. Current is passed through the phases. Therefore, the winding in which the current is concentrated in one phase becomes the W phase in the pattern (A), the V phase in the pattern (B), and the U phase in the pattern (C), and is equivalent to the current flowing in the shunt resistor 24.

If, for example, the W phase of the power line of the motor 14 is broken, no current flows through the shunt resistor 24 during energization according to the pattern (A), and the control circuit 39 cannot detect the output voltage of the peak hold circuit 27. That is, when there is a pattern in which the output voltage of the peak hold circuit 27 becomes less than a predetermined threshold value when the patterns (A) to (C) are switched, the phase in which the disconnection has occurred can be specified. The same applies to the case where the IGBT 22 of the inverter circuit 21 fails, but the overload of the motor 14 and the disconnection abnormality of the signal line of the position sensor 44 can be distinguished.

FIG. 5 shows output voltage waveforms of U, V, and W phases when a sinusoidal current is generated in the winding of the motor 14 by two-phase modulation, the horizontal axis shows the rotor angle, and the vertical axis shows the output voltage. In the actual control, the output signal obtained by multiplying the instructed PWM duty by the waveform amplitude is output as the PWM signal based on the rotor angle obtained by temporally complementing the sensor signal of the position sensor 44 and its data. .. When the disconnection is detected, the patterns (A) to (C) are realized by energizing at the rotor position indicated by the broken line in the figure. Note that (A)' and (B)' shown in the drawing will be described in the second embodiment.

FIG. 1 is a flow chart showing a process for detecting an overcurrent abnormality and a disconnection abnormality of the motor 14. The control circuit 39 executes this processing every 1 ms while the motor 14 is rotating. First, it is determined whether or not an overcurrent abnormality is detected (S1), and if not detected (NO), it is determined whether or not an overcurrent is occurring at that time (S2). Here, for example, it is determined that an overcurrent has occurred when a current of 15 A or more continues to flow for 2 μsec or more. If an overcurrent has occurred (YES), the statuses of "current detection of overcurrent" and "current of U-phase detection" are set (S3, S4), the conduction angle of the rotor position is 270°, and the voltage is equivalent to 50V. The PWM duty is output (S5). This corresponds to the switching pattern (C) shown in FIG.

On the other hand, if "YES" is determined in step S1 or "NO" is determined in step S2, it is determined whether "U phase is being detected" (S6). If "U phase is being detected" (YES), wait for 0.5 seconds (S7). Until 0.5 seconds has passed (NO), the average value of the current during detection is calculated and then the process returns (S22). When 0.5 second has elapsed in step S7 (YES), it is determined whether the average current of the U phase is less than 2 A (S8). If it is 2 A or more (NO), the status of "V phase is being detected" is set (S9), and the output is performed with the conduction angle of the rotor position of 150° and the PWM duty corresponding to the voltage of 50 V (S10). This corresponds to the switching pattern (B) shown in FIG. If the average current of the U phase is less than 2 A in step S8 (YES), the disconnection of the U phase is confirmed (S20). When it is determined that there is a disconnection abnormality, it is assumed that the electric power line of the motor 14 is disconnected. Therefore, the user's operation on the operation panel (not shown) of the washing machine 1 is set to the permanent lock state, and "abnormality display" is performed (S21). ).

If "U phase is not being detected" in step S6 (NO), it is determined whether "V phase is being detected" (S11). Subsequent steps S12 to S15 are processing corresponding to steps S7 to S10 in the case of "during V phase detection". In step S14, the status of "W phase is being detected" is set, and in step S15, the rotor position is 30° and the output is performed with the PWM duty corresponding to the voltage of 50V. This corresponds to the switching pattern (A) shown in FIG.

Further, if "V phase is not being detected" in step S11 (NO), the process proceeds to step S16. Steps S16 and S17 are processes corresponding to steps S7 and S8 in the case of “W phase detection is being performed”. Then, if "NO" is determined in step S17, "overcurrent abnormality" is confirmed (S18), and the corresponding abnormality display is performed on the operation panel (S19). That is, if one or more of the three phases have an average current value of 2 A or less, the disconnection abnormality is confirmed in step S20, and if not, the overcurrent abnormality is determined in step S19.

Next, voltage control will be described with reference to FIGS. 6 to 8. FIG. 6 is a flowchart showing a process for determining the voltage in the voltage/phase control, that is, the PWM duty, and this process is executed, for example, in a cycle of 1 msec. In the figure, the PWM duty is DUTY. Details of the phase control are also disclosed in JP-A-2014-39724. When the control circuit 39 A/D-converts the output signal of the peak hold circuit 27 and reads it (S41), the peak hold value (hereinafter referred to as the detected current value) is used as a threshold value for current control (for example, current 7. (Value corresponding to 5A) (S42). If the detected current value is equal to or more than the threshold value, the "overcurrent flag" is set to "H" (S43). That is, here, a state in which the detected current value is equal to or higher than the threshold value is referred to as “overcurrent”.

In this case, since it is determined that the duty setting in the PWM control is excessive, the duty is controlled to be decreased in the subsequent step S44. That is, the over value, which is the difference between the detected current value and the threshold value, is obtained, and the degree of reduction is changed according to the magnitude of the over value. The over value may be obtained in step S42. That is, as shown in FIG. 7A, if the over value is 0.4 A or less, the duty is not reduced and the current value is maintained. Further, if 1.6A or less, 8%, 2.4A or less, 12%, 3.2A or less, 16%, 3.6A or less, 24%, 4.0A or less, 39%. %, and if it exceeds 4.0 A, it is 47%, and so on.

In the subsequent step S45, if the duty is less than the predetermined minimum value as a result of reducing the duty as described above (YES), the duty is fixed to the minimum value (S46). If it does not fall below the minimum value (NO), the process ends.

On the other hand, if the detected current value is less than the threshold value in step S42, it is determined whether the "overcurrent flag" is "H, L" (S47). If the "overcurrent flag" is "L (reset)", there is no need to perform any particular process, and the process ends. If the "overcurrent flag" is "H", the duty is increased (S48), but with respect to the increase, the increase value is not set in multiple stages as in the case of the decrease, and the increase is shown in FIG. 7(b). Always set to 16%.

Then, at this stage, it is judged whether or not the actual duty increased in step S48 is equal to or larger than the command duty determined in the process shown in FIG. 6 (S49), and if it is less than the command duty (NO). The process is terminated as it is. If it is equal to or greater than the command DUTY (YES), the actually output DUTY is fixed to the command DUTY, that is, matched. Then, when the "overcurrent flag" is set to "L" (S50), the process ends.

FIG. 8 shows an example of changes in the detected current value and DUTY corresponding to the processing shown in FIG. The circled numbers shown in the figure correspond to the processing parts of the same circled numbers shown in FIG. The period when the detected current value does not exceed the threshold value and the command duty and the actual duty value are the same (3) "No overcurrent detection", and the actual duty value is decreased when the detected current value exceeds the threshold value. The period during which it is active is (1) “DUTY reduction processing unit”. The period during which the actual duty is increased is (2) "DUTY recovery processing section".

As shown in FIG. 8A, when the detected current value exceeds the threshold value, the actual duty decreases with respect to the command DUTY, and when the two deviate from each other, the detected current value is suppressed so as not to exceed the threshold value. The control is performed so that they match each other.

As described above, according to the present embodiment, the control circuit 39 detects the overcurrent by reading the terminal voltage of the shunt resistor 24 via the peak hold circuit 27, A/D converting it, and comparing it with the reference value. A disconnection abnormality is also detected in the processing. At that time, the switching state of the inverter circuit 21 is controlled so that the current detected by the shunt resistor 24 becomes a current that is concentrated and applied to any one-phase winding of the motor 14, and the switching state is set to 1 The phase of the current detected by the shunt resistor 24 is changed by changing the phase more than once, and the current generation states of all the phases are referred to. Specifically, the switching state in which two phases of the upper IGBTs 22a to 22c constituting the inverter circuit 21 and one phase of the lower IGBTs 22d to 22f excluding these two phases are simultaneously turned on is changed three times.

As described above, by performing the process of detecting the overcurrent and the process of detecting the disconnection abnormality, the overload of the motor 14, the disconnection abnormality of the signal line of the position sensor 44, the disconnection abnormality of the power line, and the failure of the IGBT 22 are performed. It is possible to distinguish them, and it is possible to collectively carry out these abnormality handling processing. Further, since the disconnection of three phases is individually detected, the operation is reliable. Further, the shunt resistor 24 is used for current detection without using an expensive current transformer or the like. Since the components such as the shunt resistor 24 and the peak hold circuit 27 are commonly used for controlling the overcurrent abnormality and the overcurrent of the motor 14, the cost can be reduced and the size of the circuit board can be reduced.

Instead of the above switching state, one phase of the upper IGBTs 22a to 22c and two phases of the lower IGBTs 22d to 22f excluding this one phase may be turned on at the same time.
Further, the control circuit 39 outputs a sinusoidal voltage to the motor 14 according to the energization pattern based on the timing obtained by interpolating the output intervals of the sensor signals A and B. Therefore, it is possible to drive the motor 14 with a sine wave by increasing the control accuracy even with a low cost and simple configuration.

(Second embodiment)
11 to 13 show the second embodiment. The same parts as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Different parts will be described. As shown in FIG. 11, in the second embodiment, the rotation abnormality of the motor 14 is detected instead of the detection of the overcurrent abnormality. If the rotation abnormality has not been detected (S23: NO), for example, if it is recognized that there is no change in the position sensor signal for 0.1 seconds or more (S24: YES), the "rotation abnormality is being detected" and the "first detection" are detected. The status of "medium" is set (S25, S26). Then, output is performed at a conduction angle of the rotor position of 60° and with a PWM duty corresponding to a voltage of 50V (S27). This corresponds to the switching pattern (A)' shown in FIG.

On the other hand, if "YES" is determined in step S23 or "NO" is determined in step S24, it is determined whether "first detection is in progress" (S28). If "first detection is in progress" (YES), steps S7 and S8 are executed, and then the status of "second detection is in progress" is set (S29). Then, output is performed at the conduction angle of the rotor position of 120° and at the PWM duty corresponding to the voltage of 50V (S30). This corresponds to the switching pattern (B)' shown in FIG.

If it is not "first time detection" in step S28 (NO), steps S12 and S13 are executed, and if "NO" is determined in step S13, detection of "abnormal rotation" is confirmed (S31). Then, the corresponding abnormality display is performed on the operation panel (S32).

As shown in FIG. 12, in the switching pattern (A)′, the U-phase voltage which is the first phase is “large”, the W-phase voltage which is the third phase is “0”, and the V-phase voltage which is the second phase. Is "medium", that is, about 1/2 of "large". At this time, the current shown by the solid line in the figure branches from the upper U phase to the lower V and W phases, and the current shown by the broken line flows from the upper V phase to the lower W phase. Therefore, equal currents flow in opposite directions in the V-phase winding 14v, and the current value becomes "0". Further, in the W-phase winding 14w, 1/2 of the U-phase current and the current shown by the broken line are combined, so that a current equal to the U-phase current flows. As a result, the shunt resistor 24 detects the U-phase current.

In the switching pattern (B)', the U-phase voltage is "large", the V-phase voltage is "0", and the W-phase voltage is "medium". At this time, the current shown by the solid line in the figure flows similarly to the pattern (A)', and the current shown by the broken line flows from the upper W phase to the lower V phase. Therefore, in the W-phase winding 14w, equal currents flow in opposite directions and the current value becomes "0", and in the V-phase winding 14v, 1/2 of the U-phase current and the current indicated by the broken line are combined. Current equal to the U-phase current flows. That is, in the switching pattern (B)', the second phase and the third phase are switched from the pattern (A)'.

As shown in FIG. 13, when the disconnection is not detected, the A/D converted value of the current is about 8% to 9% of the full scale, for example. On the other hand, the A/D converted value when a disconnection occurs in any of the U, V, and W phases is, for example, a value of about 4% to 6% of full scale. Therefore, by setting the determination threshold to, for example, about 7% of the full scale, it is possible to distinguish the occurrence of the wire breakage failure.

As described above, according to the second embodiment, the control circuit 39 causes the W-phase winding 14w to pass a current of the same value in the opposite direction in a state where the U-phase winding 14u is concentrated and energized. Moreover, after the switching pattern (A)' in which the current is not substantially applied to the V-phase winding 14v is executed, the energization is performed again by the switching pattern (B)' in which the V-phase and the W-phase are switched. .. That is, the disconnection can be quickly detected by executing the two switching patterns. However, it is not possible to specify in which phase the disconnection has occurred.

Further, according to the second embodiment, the switching pattern in the two-phase modulation output can be diverted as it is to detect the disconnection, so that an overcurrent is generated as in the case where the IGBTs 22 are continuously turned on. There is nothing.

(Third Embodiment)
The third embodiment shown in FIG. 14 replaces the rotation abnormality detection performed in the second embodiment with the overcurrent abnormality detection of the first embodiment.

Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 spirit of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

In the first embodiment, rotation abnormality may be detected instead of overcurrent detection.
It may be applied to three-phase modulation.
The threshold current value with respect to the detected current, the decrease value and the increase value of DUTY may be changed as appropriate. Also, a plurality of increment values may be set.
The time for averaging the currents may also be changed as appropriate.
It is not always necessary to use the IC 30.

The peak hold circuit may be configured using an operational amplifier.
Further, it is not always necessary to use the peak hold circuit for detecting the current.
The number of position sensors may be three or more.
The configuration of the motor 14 is not limited to 48 poles/36 slots.
The control circuit 39 does not necessarily have to be configured by an 8-bit microcomputer.
The relationship between the over value and the duty increase/decrease value shown in FIG. 7 is an example, and may be appropriately changed according to the individual design.
It may be applied to a drum type washing machine.

In the drawing, 1 is a fully automatic washing machine, 5 is a rotary tub, 6 is a stirring blade, 14 is a DC brushless motor, 14a is a rotor, 21 is an inverter circuit, 24 is a shunt resistor, 27 is a peak hold circuit, 30 is an IC, Reference numeral 39 is a control circuit, and 44 is a position sensor.

Claims (6)

A three-phase permanent magnet type motor that generates a rotational driving force for performing a washing operation,
An inverter circuit that drives this motor,
A current detection resistor that is inserted between the lower switching element and the ground that make up this inverter circuit,
A position sensor that detects a rotor rotation position of the motor and outputs a sensor signal,
In the process of detecting the rotation abnormality of the motor based on the sensor signal, when detecting the disconnection abnormality by A/D converting the terminal voltage of the current detection resistor and comparing it with a reference value,
The switching state of the inverter circuit is controlled so that the current detected by the current detection resistor is a current that is concentrated and applied to any one phase winding of the motor, and the switching state is changed at least once. A controller for a washing machine motor, comprising: an abnormality detection unit configured to change a phase of a current detected by the current detection resistor and refer to current generation states of all phases. A three-phase permanent magnet type motor that generates a rotational driving force for performing a washing operation,
An inverter circuit that drives this motor,
A current detection resistor that is inserted between the lower switching element and the ground that make up this inverter circuit,
When a disconnection abnormality is detected in the process of detecting an overcurrent by A/D converting the terminal voltage of the current detection resistor and comparing it with a reference value,
The switching state of the inverter circuit is controlled so that the current detected by the current detection resistor is a current that is concentrated and applied to any one phase winding of the motor, and the switching state is changed at least once. A controller for a washing machine motor, comprising: an abnormality detection unit configured to change a phase of a current detected by the current detection resistor and refer to current generation states of all phases. The anomaly detection unit applies a current of the same value in the opposite direction to the winding of the second phase in a state where the current is concentrated in the winding of the first phase and is applied to the winding of the third phase. Is a state where no current is applied,
The washing machine motor control device according to claim 1 or 2, wherein the second phase and the third phase are exchanged with each other and electricity is supplied again. The said abnormality detection part changes the switching state which turns on simultaneously two phases of the upper side switching element which comprises the said inverter circuit, and one phase of the lower side switching element which excludes these two phases 3 times. Control device for washing machine motor. The said abnormality detection part changes the switching state which turns on simultaneously the 1 phase of the upper side switching element which comprises the said inverter circuit, and the 2 phase of the lower side switching element except this 1 phase 3 times. Control device for washing machine motor. A position sensor that detects a rotor rotation position of the motor and outputs a sensor signal,
6. The washing machine motor control device according to claim 1, further comprising: a PWM control unit that PWM-controls the inverter circuit based on the sensor signal and outputs a sinusoidal voltage to the motor.

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