JP2001320894A - Motor drive - Google Patents

Abstract

(57) [Problem] In a motor drive device that drives a motor by an inverter circuit, a self-diagnosis is performed before the motor is rotationally driven to determine whether or not the overcurrent protection function operates normally. Prevent abnormal overheating. SOLUTION: DC power of a rectifier circuit 3 connected to an AC power supply 1 is converted into AC power by an inverter circuit 4 to drive a motor 5, and a control means 11 controls the inverter circuit 4. The control means 11 includes an inverter drive circuit 11b for driving the inverter circuit 4, an overcurrent determination circuit 11d for determining an overcurrent from an output signal of the current detection means 6 for detecting a current of the inverter circuit 4, and an overcurrent determination circuit 11d.
And an inverter output control circuit 11a for controlling the output of the inverter drive circuit 11b in accordance with the output signal of the above. An abnormality is determined from the output signal of 11d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving device for driving a motor by an inverter circuit.

[0002]

2. Description of the Related Art In recent years, an electric washing machine or a dishwasher for home use has been proposed in which the rotation speed of a motor is controlled by an inverter device to improve dehydration performance or pump performance.

Conventionally, this type of washing machine has been disclosed in
No. 0960. That is,
An overcurrent of the inverter circuit is detected by an overcurrent protection circuit, and a signal of the overcurrent protection circuit is applied to a microcomputer for controlling the inverter circuit, thereby protecting the circuit from overcurrent.

[0004]

However, in such a conventional configuration, if the overcurrent protection circuit for protecting the inverter circuit has failed, the power switching element of the inverter circuit may be destroyed, or There is a drawback that an overcurrent flows through the motor and the motor overheats.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. Before the motor is driven to rotate, a self-diagnosis is made as to whether or not the overcurrent protection function operates normally. The purpose of the present invention is to prevent short circuit failure of the inverter circuit and abnormal overheating of the motor.

[0006]

In order to achieve the above object, the present invention converts the DC power of a rectifier circuit connected to an AC power supply into AC power by an inverter circuit, drives a motor, and controls the inverter circuit. Control means for controlling an inverter circuit; an inverter drive circuit for driving the inverter circuit; an overcurrent determination circuit for determining an overcurrent from an output signal of the current detection means for detecting a current of the inverter circuit; and an overcurrent determination circuit. An inverter output control circuit that controls the output of the inverter drive circuit by the output signal of
Before rotating the motor, at least one of the motor coils
The phase is forcibly energized for a predetermined time, and an abnormality is determined based on an output signal of the overcurrent determination circuit.

Thus, it is possible to make a self-diagnosis as to whether the overcurrent protection function operates normally before the motor is driven to rotate, and in the case of an abnormality, stop the drive of the inverter circuit to notify the abnormality, Not only the overcurrent protection function and the failure of the motor circuit can be determined before operation, but also the short-circuit failure of the inverter circuit and abnormal overheating of the motor can be prevented.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided an AC power supply, a rectifier circuit connected to the AC power supply,
An inverter circuit for converting DC power of the rectifier circuit into AC power, a motor driven by the inverter circuit, current detection means for detecting a current of the inverter circuit, and control means for controlling the inverter circuit,
An inverter drive circuit for driving the inverter circuit; an overcurrent determination circuit for determining an overcurrent from an output signal of the current detection means; and an output of the inverter drive circuit based on an output signal of the overcurrent determination circuit. And an inverter output control circuit for controlling the operation of the motor, forcibly energizing at least one phase of the motor coil for a predetermined time before rotating the motor, and determining an abnormality based on an output signal of the overcurrent determination circuit. Before the motor is rotationally driven, a current is simulated, and the output signal of the overcurrent determination circuit allows the overcurrent protection function of the overcurrent determination circuit, inverter output control circuit, etc. A self-diagnosis can be performed to determine whether or not the operation is normal.In the case of an abnormality, the inverter circuit can be stopped and the abnormality can be notified. Not only the fault can be determined before the operation, it is possible to prevent short-circuit failure or abnormal overheating of the motor of the inverter circuit.

According to a second aspect of the present invention, in the first aspect of the present invention, the overcurrent determination circuit comprises a comparing means,
An overcurrent setting means capable of changing an overcurrent setting value, wherein the overcurrent setting means lowers the current setting value of the overcurrent setting means before rotating the motor so as to determine the overcurrent,
The overcurrent determination circuit can be operated at a normal motor current or less, and the operation of the overcurrent determination circuit can be performed without flowing an abnormal current.
Alternatively, the operation of the overcurrent protection function can be confirmed.

According to a third aspect of the present invention, in the first aspect of the present invention, the control means includes an inverter circuit connected to the P
The motor current is controlled by the WM control, and at least one phase of the motor coil is forcibly energized at a predetermined conduction ratio for a predetermined time before the motor is rotationally driven, and abnormality is determined based on an output signal of the overcurrent determination circuit. Since the operation of the overcurrent determination circuit can be confirmed by reducing the motor current by the PWM control, even if the overcurrent determination circuit has failed, the self-diagnosis is performed with a small motor current. There is no danger of overheating the motor or demagnetizing the permanent magnet of the rotor.

According to a fourth aspect of the present invention, in the third aspect of the invention, the inverter circuit comprises a three-phase full-bridge inverter circuit, and the control means performs PWM control on the upper arm transistor of the inverter circuit. In this way, the motor current is controlled so that the current is forcibly supplied at a predetermined conduction ratio for a predetermined time, and the upper arm transistor driving power supply of the inverter circuit can be easily formed by PWM controlling the upper arm transistor. By employing the bootstrap drive power supply, the inverter drive circuit can be made simple and inexpensive.

According to a fifth aspect of the present invention, there is provided an AC power supply, a rectifier circuit connected to the AC power supply, an inverter circuit for converting DC power of the rectifier circuit into AC power, and a plurality of power supplies driven by the inverter circuit. A motor, load switching means for switching the output of the inverter circuit, current detection means for detecting the inverter circuit current, and control means for controlling the inverter circuit and the load switching means. An inverter circuit selectively connectable to at least two of the plurality of motors, forcibly energizing at least one phase of the motor coil for a predetermined time before driving one of the plurality of motors by the inverter circuit; Abnormality is determined based on the current value detected by the current detection means. The self-diagnosis of whether the current determination circuit operates normally and the confirmation of whether the load switching means is normally connected to the motor can be performed. Alternatively, a highly reliable motor drive device that can prevent demagnetization of the motor and the like can be realized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a washing machine will be described below with reference to the drawings.

(Embodiment 1) As shown in FIG. 1, an AC power supply 1 applies AC power to a rectifier circuit 3 via a line filter 2 and converts the rectifier circuit 3 into DC power. The rectifier circuit 3 constitutes a voltage doubler rectifier circuit. When the AC power supply 1 has a positive voltage, the full-wave rectifier diode 30 provides a capacitor 31.
a, and when the AC power supply 1 has a negative voltage, the capacitor 3
1b and capacitors 31a, 31 connected in series
A double voltage DC voltage is generated at both ends of b, and the double voltage DC voltage is applied to the inverter circuit 4.

The inverter circuit 4 is constituted by a three-phase full-bridge inverter circuit comprising six power switching semiconductors and an anti-parallel diode, and is generally an intelligent circuit including a power transistor and an anti-parallel diode, and a drive circuit and a protection circuit built therein. It is composed of a power module (hereinafter referred to as IPM). Inverter circuit 4
Motor 5 is connected to the output terminal of the agitating blade (not shown)
Alternatively, a dehydration tank (not shown) is driven.

The motor 5 is constituted by a DC brushless motor, and a first position detecting means 5a detects a relative position (rotor position) between a permanent magnet constituting a rotor and a stator. The first position detecting means 5a is usually constituted by a Hall IC. Current detecting means 6, a so-called shunt resistor, is connected between the negative voltage terminal of the inverter circuit 4 and the negative voltage terminal of the rectifier circuit 3.

A water supply valve 7, a drain valve 8, and a clutch 9 are connected between the output AC voltage terminals of the line filter 2, and are controlled by a switching means 10. The water supply valve 7 supplies tap water to a washing tub (not shown), and is constituted by an electromagnetic valve, and the drain valve 8 controls drainage of water in the washing tub. The clutch 9 controls whether the rotation drive shaft of the motor 5 is connected to the stirring blade or the dewatering tub.

The switching means 10 is constituted by a solid state relay such as a bidirectional thyristor or a mechanical relay.

The control means 11 controls the inverter circuit 4 and the switching means 10, and includes an inverter output control circuit 11a composed of a microcomputer.
An inverter driving circuit 11b for controlling the inverter circuit 4 based on an output signal of the inverter output control circuit 11a to control the rotational driving of the motor 5;
And an overcurrent judging circuit 11d for detecting an overcurrent of the inverter circuit 4 based on an output signal of the current detecting means 6 and applying an abnormal signal to the inverter output control circuit 11a.

The overcurrent judging circuit 11d can change the overcurrent set value by the signal S from the inverter output control circuit 11a. The output signal of the overcurrent judging circuit 11d is supplied to an interrupt terminal (I
In addition to the RQ terminal, the microcomputer gives priority to the interrupt signal and inhibits the inverter drive output signal.

The inverter circuit 4 includes, as shown in FIG.
Six power MOSFETs (transistors) 40a, 40b, 40 constituting a three-phase full-bridge inverter circuit
c, 40a ', 40b', 40c 'and six antiparallel diodes 41a, 41b, 41c, 41a', 41b ',
41c 'and its gate drive circuits 42a, 42b,
42c, 42a ', 42b', and 42c '.

The power MOSFETs 40a, 40b, 40c connected to the positive terminal VP of the DC power supply are upper arm power MOSFETs, and the power MOSFETs 40a ', 40b', 40 connected to the negative terminal VN of the DC power supply.
c ′ is called a lower arm power MOSFET.

Upper arm power MOSFETs 40a, 40
Upper arm drive IC 4 for driving gate terminals of b and 40c
The gate output terminals of 2a, 42b, 42c are connected to the gate terminals of the respective power MOSFETs 40a, 40b, 40c, and the minus N terminal is connected to the source terminals of the power MOSFETs, ie, the inverter output terminals U, V, W, respectively.

Upper arm drive ICs 42a, 42b, 42c
Input terminals Up, Vp, Wp are at 5V signal level,
Power MOSFE by high voltage level conversion circuit inside IC
A gate drive signal is applied to the T gate terminal. The lower arm drive ICs 42a ', 42b', and 42c 'do not require a high voltage level conversion circuit, and the gate drive signals are simply 5 V signal levels and the power MOSFETs 40a', 40b ', and 40c'.
Is added to Gate drive voltage is usually DC12-15V
And the lower arm drive IC from the gate drive power supply 43
12 to the power supply terminals Vb of 42a ', 42b', and 42c '.
15V is applied.

Upper arm drive ICs 42a, 42b, 42c
Is a circuit system called a bootstrap system, and resistors 44a, 44
Power energy is stored in the capacitors 46a, 46b, 46c via a series circuit of the diodes 46a, 46c and the diodes 45a, 45b, 45c, and the capacitors 46a, 46b, 4c
6c is a positive terminal of the upper arm drive IC 42a, 42b,
The negative terminal is connected to the N terminal of the upper arm drive ICs 42a, 42b, and 42c, that is, the source terminal of the power MOSFET. Note that there is no particular problem even if an insulated gate bipolar transistor (IGBT) is used instead of the power MOSFET.

As shown in FIG. 3, the overcurrent judging circuit 11d comprises a comparing means 11e and an overcurrent setting means 11f capable of changing an overcurrent set value.
The signal VL of the current detecting means 6 is compared with the output signal Vs of the overcurrent setting means 11f, and when the inverter current exceeds the set overcurrent, an abnormal interrupt signal IRQ is generated. The output signal Vs of the overcurrent setting means 11f can be changed by the inverter output control means 11a.

Lower arm power MOS of inverter circuit 4
Since the minus terminal VN of the FET and the ground potential of the control means 11 are common, the signal VL of the current detection means 6 has a negative potential. Therefore, since the comparing means 11e needs to compare with a negative potential, it has a special circuit as shown in FIG.

The signal VL of the current detecting means 6 is a resistor 110a
A noise filter is provided by an RC integrating circuit including a resistor 110a and a capacitor 110b, and a signal Vi is applied to a plus terminal input of the comparator 112 via an RC integrating circuit including a resistor 111a and a capacitor 111b. A resistor 113 is connected between the plus terminal input signal Vi and the DC power supply Vcc so that the potential of the plus terminal input Vi becomes higher than the ground potential.

When the inverter circuit current increases, the signal V
L increases to the negative voltage side, the input signal Vi of the comparator 112 decreases, and when the input signal Vi decreases below the set potential Vs, the output signal OC becomes low, and the inverter output control means 11a receives the interrupt signal IRQ and Driving is stopped with top priority.

The output signal Vs of the overcurrent setting means 11f can be set and changed in two steps by the inverter output control means 11a. A resistor 114a and a resistor 114b are connected in series between the DC power supply Vcc and the ground. 112 is connected to the minus input terminal. In addition, resistance 1
The collector / emitter terminals of the transistor 115 are connected in parallel with 14b, and the setting signal Vs of the comparator 112 is controlled by switching on / off via the base resistor 116 by the output signal S of the inverter output control means 11a. ing.

When the setting signal Vs of the comparator 112 is increased, the overcurrent set value is decreased. When the setting signal Vs is decreased, that is, when the transistor 115 is turned on, the overcurrent set value is increased.
Is turned on, and the overcurrent set value is set higher.

The operation of the above configuration will be described with reference to FIGS. FIG. 4 shows an inverter driving circuit 1
1b, the current I of the current detecting means 6, and the output signal OC of the overcurrent determination circuit 11d.
p and Wp are upper arm power MOSFETs 40a, 40
Drive signals Un, Vn, and Wn of b and 40c indicate drive signals of the lower arm power MOSFETs 40a ', 40b' and 40c '.

An abnormality determination routine is started from step 200 in FIG. 5, and a bootstrap subroutine is executed in step 201. A section from time t0 to time t1 is a bootstrap operation section, and the lower arm power MOSFET is used.
T40a ', 40b', and 40c 'are simultaneously turned on and off.
When b 'and 40c' are turned on, the gate drive power supply 43 supplies the resistors 44a, 44b and 44c and the diodes 45a and 45c.
b, 45c via a series circuit of capacitors 46a, 46c.
b, 46c are charged with electric charges, and the capacitors 46a, 46c are charged.
The terminal voltages of b and 46c are substantially equal to the voltage of the gate drive power supply 43.

Next, the routine proceeds to step 202, where the overcurrent set value is reduced. Specifically, it controls the overcurrent setting means 11f to increase the setting signal Vs of the comparator 112,
Decrease the overcurrent setting. For example, the overcurrent set value of 5 A is usually set to about 0.5 A.

Next, proceeding to step 203, the driving signal Wn is applied to make the lower arm power MOSFET 41c 'conductive, and proceeding to step 204, the PWM-controlled driving signal Up is added, and the upper arm power MOSFET 41a is turned on at the period T0. On / off control is performed at a predetermined duty in the period Ta. The on-off duty at this time, that is,
The PWM value is a set value lower than the normal operation value. However, if the overcurrent set value is set to 0.5 A, it is necessary to set the inverter circuit current to a value that is 0.5 A or more.

At time t2, the inverter circuit current flows from the U-phase to the W-phase of the motor 5 from the upper arm power MOSFET 41a, and the lower arm power MOSFET 41
The current flows to the negative voltage terminal of the DC power supply 3 via the current detecting means 6 after flowing to c ′.

At the moment when the upper arm power MOSFET 41a is turned off, a flywheel current flows through the anti-parallel diode 42a 'of the lower arm power MOSFET 41a', the U-phase potential becomes equal to the minus potential of the inverter circuit 4, and the gate drive power supply 43 charges the capacitor 46a via a series circuit of a resistor 44a and a diode 45a, and performs charging by a bootstrap method. Therefore, when the upper arm power MOSFET 41a is subjected to PWM control, the capacitor 46a is always charged, so that there is no particular problem even if the drive pulse widths t2 to t4 are increased.

In step 205, it is determined whether or not the overcurrent signal OC, that is, the interrupt signal IRQ is generated. If the motor 5 is normal, the interrupt signal IRQ is generated at time t3 and the process jumps to step 206. Stop all inverter drive signals. Next, the routine proceeds to step 207, in which the overcurrent set value is increased to the value of the normal operation, and the routine proceeds to step 208, where after the same bootstrap operation as in step 201, the motor rotation driving subroutine of step 209 is executed.

If no interrupt signal is generated in step 205, the process proceeds to step 210, where the power MOSFET
It is determined whether or not the forced conduction period has elapsed for a predetermined time, and if within the predetermined time, the process returns to step 203. If the interrupt signal IRQ does not occur even after the predetermined time has elapsed, the process proceeds to step 211, where an abnormality is determined and the inverter drive is started. The signal is stopped, and the process proceeds to step 212 to execute an abnormality processing subroutine such as abnormality notification or abnormality memory.

In the above embodiment, since the coil connection of the motor 5 is a star connection, the two phases U and W are energized. However, if the connection is a delta connection, one phase and the other two phases are connected in series. , But the operation is the same. When the U-phase and the W-phase are energized, and then the V-phase lower-arm power MOSFET 41b 'is energized and the U-phase upper-arm power MOSFET 41a is PWM-controlled, the current of all phases can be checked. In particular, disconnection of the motor coil and the like can be reliably determined because no current flows. Of course, an abnormality can also be determined if the overcurrent determination circuit 11d fails or is broken due to disconnection.

(Embodiment 2) FIG. 6 shows an embodiment in which a plurality of motors are driven by one inverter circuit, in which a washing motor of a washing machine and a pump motor for supplying bath water are driven. The connection of the basic inverter circuit is the same as that of FIG.

As shown in FIG. 6, the load switching means 12
The output of the inverter circuit 4 is connected to the output of the inverter circuit 4, and the output of the inverter circuit 4 is connected to either the first motor (washing motor) 5 or the second motor (pump motor) 13.
The load switching means 12 comprises a 2c contact relay,
The V phase is switched by a relay, and the W phase is commonly connected.

The control means 11 'additionally includes a relay drive circuit 11g for controlling the switching of the relay 12, and a second position detection means 11h called a sensorless circuit for extracting a position signal from the terminal voltage of the second motor 13. Have.

The sensorless circuit extracts the position signals φ1, φ2, φ3 shifted by 90 degrees from the half of the peak voltages of the motor terminal voltages Vu, Vv, Vw as shown in FIG. There is no need to provide a position signal of an IC or the like, and a connecting wire can be omitted, so that an inexpensive DC brushless motor can be configured.

However, in order to detect the back electromotive force of the motor, it is necessary to perform so-called one-side PWM control for performing PWM control on the upper arm power MOSFET or the lower arm power MOSFET. Considering the bootstrap method, the upper arm side PWM is preferable. Since the first motor 5 is provided with the first position detecting means 5a, the driving of the first motor 5 may be a sine wave drive or an alternating PWM.

The overcurrent determination circuit 11d 'changes overcurrent detection levels when driving the first motor and when driving the second motor, and is basically the same as that shown in FIG. It is. That is, the overcurrent setting value is changed according to the drive motor to be switched by the load switching means 12, which is constituted by the comparing means 11e and the overcurrent setting means 11f capable of changing the overcurrent setting value.

In the case of a washing machine, since the first motor 5 is a washing motor and the second motor 13 is a pump motor, the output capacities of the motors are about 300 W and about 30 W, and the overcurrent set values are greatly different. Therefore, as described with reference to FIGS. 4 and 5, when the operation of the overcurrent protection function is confirmed by lowering the overcurrent set value before driving the first motor 5, Since the abnormality can be detected after setting the overcurrent set value, there is a feature that it is not necessary to change the overcurrent set value in many steps for the abnormality detection.

The program flowchart of the microcomputer constituting the inverter output control circuit 11a is basically the same as that of FIG.
To perform an abnormality detection operation from step 200. If the output of the inverter circuit 4 is connected to the side of the second motor 13 due to the welding of the relay 12 or the failure of the relay drive circuit 11g, the motor coil series resistance of the second motor 13 is large. As the overcurrent detection signal OC is not generated, an abnormality is determined. That is, not only the self-diagnosis of the abnormality protection device such as the overcurrent determination circuit 11d ', but also the load switching means 12
Has the feature of being able to judge abnormalities even if welding failure occurs on the side,
It is possible to prevent an accident in which a large current flows to the second motor 13 side to cause demagnetization and abnormal overheating.

If there is a D / A conversion circuit in the inverter output control circuit 11a 'comprising a microcomputer, FIG.
The overcurrent setting means 11f as described above is unnecessary, and there is no problem even if the output signal of the D / A conversion circuit is directly applied to the setting input Vs of the comparison means 11e, and it is possible to change the overcurrent setting value more finely.

[0050]

As described above, according to the first aspect of the present invention, an AC power supply, a rectifier circuit connected to the AC power supply, and an inverter for converting DC power of the rectifier circuit into AC power. Circuit, a motor driven by the inverter circuit, current detection means for detecting a current of the inverter circuit, and control means for controlling the inverter circuit, wherein the control means drives the inverter circuit to drive the inverter circuit. A circuit, an overcurrent determination circuit that determines an overcurrent from an output signal of the current detection unit, and an inverter output control circuit that controls an output of the inverter drive circuit based on an output signal of the overcurrent determination circuit, Before the motor is driven to rotate, at least one phase of the motor coil is forcibly energized for a predetermined time, and an abnormality is determined based on an output signal of the overcurrent determination circuit. This makes it possible to self-diagnose whether the overcurrent protection function operates normally before rotating the motor, and in the case of an abnormality, stop the inverter circuit drive to notify the abnormality, Not only can a circuit failure be determined before operation, but also a short circuit failure in the inverter circuit and abnormal overheating of the motor can be prevented.

According to the second aspect of the present invention, the overcurrent judging circuit includes a comparing means and an overcurrent setting means capable of changing an overcurrent set value, wherein the overcurrent setting circuit changes the overcurrent setting value before driving the motor. Since the overcurrent is determined by lowering the current setting value of the current setting means, the overcurrent determination circuit can be operated at a normal motor current or less, and the operation of the overcurrent determination circuit can be performed without flowing an abnormal current. Or the operation of the overcurrent protection function can be confirmed.

According to the third aspect of the present invention, the control means controls the motor current by performing PWM control on the inverter circuit, so that at least one phase of the motor coil has a predetermined time period before the motor is driven to rotate. Since the power is forcibly supplied at a predetermined conduction ratio and the abnormality is determined based on the output signal of the overcurrent determination circuit, the operation of the overcurrent determination circuit can be confirmed by reducing the motor current by the PWM control. Even if the overcurrent determination circuit has failed, the self-diagnosis is performed with a small motor current, so that there is no danger that the motor will overheat or the permanent magnet of the rotor will be demagnetized.

According to the invention, the inverter circuit is constituted by a three-phase full-bridge inverter circuit, and the control means controls the motor current by performing PWM control on the upper arm transistor of the inverter circuit. Then, the power is forcibly supplied for a predetermined time at a predetermined conduction ratio. Therefore, by controlling the upper arm transistor by PWM, a power supply for driving the upper arm transistor of the inverter circuit can be easily formed. The use of a power supply makes it possible to make the inverter drive circuit simple and inexpensive.

According to the fifth aspect of the present invention, an AC power supply, a rectifier circuit connected to the AC power supply, an inverter circuit for converting DC power of the rectifier circuit to AC power, and the inverter circuit A plurality of motors to be driven; load switching means for switching an output of the inverter circuit; current detection means for detecting the inverter circuit current; and control means for controlling the inverter circuit and the load switching means. Switching means enables the inverter circuit to be selectively connected to at least two of the plurality of motors, and forcibly forces at least one phase of the motor coil for a predetermined time before driving one of the plurality of motors by the inverter circuit. The motor is turned on because the current is supplied and the abnormality is determined based on the current value detected by the current detecting means. Self-diagnosis of whether the overcurrent determination circuit operates normally, and whether or not the load switching means is normally connected to the motor can be checked. A highly reliable motor driving device that can prevent overcurrent or demagnetization of the motor can be realized.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of a motor drive device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of an inverter circuit of the motor drive device.

FIG. 3 is a circuit diagram of an overcurrent determination circuit of the motor drive device.

FIG. 4 is a time chart of abnormality determination of the motor drive device.

FIG. 5 is a flowchart of abnormality determination of the motor drive device.

FIG. 6 is a block circuit diagram of a motor drive device according to a second embodiment of the present invention.

FIG. 7 is a time chart of the position detecting means of the motor drive device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 3 Rectifier circuit 4 Inverter circuit 5 Motor 6 Current detection means 11 Control means 11a Inverter output control circuit 11b Inverter drive circuit 11d Overcurrent judgment circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02P 6/04 H02P 6/02 301 (72) Inventor Hisashi Hagiwara 1006 Kazuma Kazuma, Kadoma City, Osaka Matsushita Electric Industrial F-term within the company (reference) 5G004 AA05 AB02 BA03 BA04 CA02 CA08 DC03 EA01 5G042 FF01 FF07 FF09 FF23 FF32 5G053 AA01 BA01 DA01 EB01 FA04 5H007 AA17 BB06 CA02 CB02 CB05 CC23 DB01 DB07 DC02 EA02 A03 FA13 EB01 EC10 GG01 JJ02 JJ06 JJ18 JJ20 SS07 TT05 TT07 TT15 UA05 UA06 XA12 XB10

Claims (5)

[Claims] An AC power supply, a rectifier circuit connected to the AC power supply, an inverter circuit for converting DC power of the rectifier circuit into AC power, a motor driven by the inverter circuit, and a current for the inverter circuit. Current detecting means for detecting, and control means for controlling the inverter circuit, the control means comprising: an inverter driving circuit for driving the inverter circuit; and an overcurrent for judging an overcurrent from an output signal of the current detecting means. A determination circuit; and an inverter output control circuit for controlling an output of the inverter drive circuit based on an output signal of the overcurrent determination circuit, wherein at least one phase of a motor coil is forcibly forced for at least one phase before the motor is rotationally driven. And a motor drive device configured to determine whether an abnormality has occurred based on an output signal of the overcurrent determination circuit. 2. An overcurrent judging circuit comprising a comparing means and an overcurrent setting means capable of changing an overcurrent set value, wherein the overcurrent setting means lowers the current set value of the overcurrent setting means before driving the motor to rotate. The motor drive device according to claim 1, wherein an overcurrent is determined. 3. The control means controls the motor current by PWM-controlling the inverter circuit, and at least applies a predetermined time to at least one phase of the motor coil before rotating the motor.
2. The motor drive device according to claim 1, wherein current is forcibly applied at a predetermined conduction ratio, and abnormality is determined based on an output signal of an overcurrent determination circuit. 4. The inverter circuit comprises a three-phase full-bridge inverter circuit, and the control means controls a motor current by performing PWM control on an upper arm transistor of the inverter circuit, and controls the motor current for a predetermined time and a predetermined conduction ratio. 4. The motor drive device according to claim 3, wherein current is forcibly supplied. 5. An AC power supply, a rectifier circuit connected to the AC power supply, an inverter circuit for converting DC power of the rectifier circuit into AC power, a plurality of motors driven by the inverter circuit, Load switching means for switching the output, current detection means for detecting the inverter circuit current, and control means for controlling the inverter circuit and the load switching means, wherein the load switching means connects the inverter circuit to a plurality of motors. At least 2
And one of the plurality of motors is forcibly energized for at least one phase of a motor coil for a predetermined time before driving one of the plurality of motors by an inverter circuit. A motor drive device that determines an abnormality.