JP2001178184A - Inverter device and electric washing machine using the same - Google Patents

Abstract

(57) [Problem] To reliably detect a back electromotive force waveform generated in an armature winding to drive a motor even when a load fluctuates during driving of the motor as a synchronous motor. SOLUTION: A control means 3 for controlling on / off of switching means 2a to 2f constituting an inverter circuit 2, an applied voltage control means 4 for controlling an applied voltage of armature windings 1b to 1d, and an armature winding 1b to A voltage detecting means 5 for detecting a terminal voltage of 1d, a comparing means 6 for comparing an output of the voltage detecting means 5 with a reference voltage, and a reference voltage setting means 7 for setting a reference voltage are provided. 1 is controlled as a synchronous motor, and the speed of the motor 1 is increased.
And the applied voltage control means 4 controls the load angle of the motor 1 to increase, and then the control means 3 controls the switching means 2 a to 2 f on and off according to the output of the comparison means 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter for driving an electric motor having a rotor having a permanent magnet, and an electric washing machine having the inverter.

[0002]

2. Description of the Related Art FIG. 10 is a circuit diagram of a main part of a conventional inverter device.

The electric motor 1 is composed of a rotor having a permanent magnet 1a and a stator having a three-phase winding composed of three armature windings 1b to 1d.

[0004] The inverter circuit 2 has a three-phase six-stone configuration with switching means 2a, 2b, 2c on the high potential side and switching means 2d, 2e, 2f on the low potential side. The switching means 2a to 2f are constituted by a parallel circuit of an IGBT and a reverse connection diode capable of supporting high-frequency switching and large current capacity.

The control means 41 is composed of a microcomputer or a plurality of logic circuits.
On / off control is performed on 2f for a period of 120 electrical degrees.

The applied voltage control means 42 is provided in a microcomputer constituting the control means 41, and controls the energization ratio of the switching means 2a to 2f during the ON period to thereby control the armature windings 1b to 1d. The average value of the applied voltage is controlled. That is, the voltage applied to the electric motor 1 is controlled by pulse width modulation (PWM).

The voltage detecting means 43 includes voltage dividing circuits 43a and 43b each including at least two resistors and one capacitor.
43c is connected to each terminal of the armature windings 1b to 1d.

The comparing means 44 comprises three comparators 44
a, 44b, and 44c.
The outputs of 3a, 43b and 43c are compared with the reference voltage set by the reference voltage setting means 45, and a high or low is output to the control means 41.

The reference voltage setting means 45 includes a three-phase virtual neutral point circuit 45d in which at least three resistors 45a, 45b, 45c having the same constant are star-connected, and a neutral point voltage of the virtual neutral point circuit 45d. And a voltage dividing circuit 45e composed of at least two resistors for dividing the voltage.

The AC power supply 9 is connected to a rectifier circuit 10, and the rectifier circuit 10 is configured as a voltage doubler rectifier circuit by a series circuit of a diode bridge 10a and two smoothing capacitors 10b and 10c. The rectifier circuit 10 supplies DC power to the inverter circuit 2.

FIG. 11 shows a time chart of drive control of the electric motor 1. (I) shows the output frequency of the power output from the inverter circuit 2. (J) shows the armature windings 1 b to 1 b controlled by the applied voltage control means 42.
The average value of the applied voltage d is shown.

The operation will be described with reference to FIGS. t
When the operation of the motor 1 is started at 0, the switching means 2a and 2e are turned on by the applied voltage v0 during the period from t0 to t1, and power is supplied to the armature windings 1b and 1c. As a result, an N-pole or S-pole magnetic field is generated at the teeth (teeth) of the iron core around which the armature windings 1b and 1c are wound, and the S magnet of the permanent magnet 1a is generated.
The pole and the N pole are attracted, and the relative position of the permanent magnet 1a with respect to the armature windings 1b to 1d is determined.

[0013] From time t1, the control means 41 controls the switching means 2a to drive the motor 1 as a synchronous motor.
To 2f are on / off controlled. At this time, the control unit 41 controls the switching units 2a to 2f to be turned on only during a period of 120 electrical degrees. This allows
A rotating magnetic field proportional to the output frequency of the inverter circuit 2 is generated in the armature windings 1b to 1d.
The rotor is rotationally driven by an electromagnetic force generated therebetween. t
In the period from 1 to t2, the control unit 41 controls the switching units 2a to 2f so that the output frequency of the inverter circuit 2 increases. The applied voltage control unit 42 controls the energization ratio of the switching units 2a to 2f so that the average value of the applied voltages of the armature windings 1b to 1d increases.

At t2, the output frequency of the inverter circuit 2 becomes a predetermined value f1. That is, when the motor 1 is not out of synchronization, the motor 1 is rotating at a speed proportional to the predetermined frequency f1. At this time, the armature windings 1b to
The average value of the applied voltage of 1d is v6. After t2, the control unit 41 controls the switching units 2a to 2f to turn on and off according to the logic output from the comparison unit 44. The applied voltage control means 42 performs PWM control on the duty ratio of the switching means 2a to 2f so that the average value of the applied voltages to the armature windings 1b to 1d increases.

[0015]

As described above, in the conventional inverter device, when starting the motor,
Regardless of the output of the comparing means, the control means drives the motor as a synchronous motor, and then controls the switching means on / off according to the output of the comparing means,
The motor drives the motor as a brushless DC motor. In order to reliably operate the motor as a synchronous motor due to a large variation in the amount of the laundry to be washed, such as an electric washing machine, there is sufficient armature winding of the motor. Supplying a current, as a result, when the load is small, the current flowing through the armature winding with respect to the output of the voltage detection means has a large delay phase, and the voltage detection means is generated in the armature winding There is a problem that the back electromotive force cannot be detected, and the motor does not operate when the motor is controlled as a brushless DC motor. In addition, this subject had a tendency to become more remarkable as it became a copper machine.

The present invention solves the above-mentioned problems of the conventional inverter device. Even if the load changes every time the motor is started, the motor is started reliably, and thereafter the armature is reliably started. It is an object of the present invention to provide an inverter device that drives the electric motor based on a back electromotive force waveform generated in a winding, and an electric washing machine using the same.

[0017]

In order to achieve the above object, the present invention provides a motor having a permanent magnet in a rotor and an armature winding in a stator, an inverter circuit connected to the motor, and Control means for controlling a switching means constituting an inverter circuit; applied voltage control means for controlling an applied voltage of the armature winding; voltage detection means for detecting a terminal voltage of the armature winding; Comparing means for comparing the output voltage of the means with a reference voltage, and reference voltage setting means for setting the reference voltage, wherein the control means is driven as a synchronous motor when the motor is started,
Since the load angle is increased and the switching means is controlled in accordance with the output of the comparison means, the current of the motor fluctuates while the motor is driven as a synchronous motor, and the current flowing through the armature winding is reduced. Even if the phase is delayed with respect to the back electromotive force generated in the slave winding, this state is corrected, and the voltage detection means reliably detects a waveform in the range of about 30 degrees behind the zero voltage of the back electromotive force. After that, the motor can be controlled according to the back electromotive force waveform.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 of the present invention provides a motor having a permanent magnet in a rotor and an armature winding in a stator, an inverter circuit connected to the motor, and the inverter. Control means for controlling switching means constituting a circuit; applied voltage control means for controlling an applied voltage of the armature winding; voltage detection means for detecting a terminal voltage of the armature winding; and the voltage detection means Comparison means for comparing the output voltage and the reference voltage, and reference voltage setting means for setting the reference voltage, the control means is driven as a synchronous motor at the time of starting the motor, after that, increasing the load angle, Since the switching means is controlled in accordance with the output of the comparing means, a current flowing through the armature winding changes due to a change in the load of the motor during driving as a synchronous motor. Even if the phase is delayed with respect to the back electromotive force generated in the wire, this state is corrected, and the voltage detecting means detects a waveform in the range of 30 degrees delayed from zero voltage of the back electromotive force generated in the armature winding. The electric motor can be reliably driven as a brushless DC motor based on the back electromotive force.

According to a second aspect of the present invention, in the first aspect, the control means controls on / off of the switching means so as to increase the speed of the motor, and the applied voltage control means comprises an armature. Since the load angle is increased by controlling the applied voltage of the winding to a predetermined value, the motor is accelerated, and the brushless DC motor is controlled based on the back electromotive force generated in the armature winding while accelerating the motor. it can.

According to a third aspect of the present invention, in the first aspect of the present invention, the applied voltage control means adjusts the applied voltage of the armature winding at a smaller increase rate than the speed increase rate of the motor. Since the load angle is increased by controlling the motor to increase, the motor can be controlled as a brushless DC motor based on the back electromotive force generated in the armature winding while accelerating the motor. Loss of synchronization can be prevented during the period when the motor is driven as a synchronous motor, particularly immediately before control as a brushless DC motor.

According to a fourth aspect of the present invention, in the first aspect of the invention, the control means controls on / off of the switching means so that the speed of the motor becomes a predetermined value, and the applied voltage control means comprises: Since the load angle is increased by controlling the voltage applied to the armature winding to decrease, even if the load fluctuates while the motor is driven as a synchronous motor, the motor is reliably driven at a predetermined speed. Can be controlled as a brushless DC motor based on the back electromotive force generated in the armature winding.

According to a fifth aspect of the present invention, in the first aspect of the present invention, there is provided a determining means for determining that the load angle is within a predetermined range. Then, the switching means is turned on / off in accordance with the output of the comparison means, so that the electric motor can be detected by the brushless DC motor in a state where the voltage detection means can surely detect a predetermined phase of the back electromotive force waveform generated in the armature winding. As a result, an inverter device and an electric washing machine with stable performance can be realized.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the determining means includes an on / off state of the switching means in accordance with an output signal of the comparing means;
Since the on / off state of the switching means output by the control means is compared, when switching the control of the electric motor from the control as a synchronous motor to the control as a brushless DC motor, there is no need to change the on / off state of the switching means. Switching can be realized.

According to a seventh aspect of the present invention, in accordance with the fifth or sixth aspect of the present invention, the applied voltage control means receives the output of the determination means and applies the applied voltage to the armature winding. Therefore, when the control of the motor is switched from a control as a synchronous motor to a control as a brushless DC motor, a decrease in the speed of the motor can be suppressed.

According to an eighth aspect of the present invention, the electric washing machine according to any one of the first to seventh aspects includes the inverter device according to any one of the first to seventh aspects. Even if the amount of the laundry changes and the load of the electric motor changes, and even if the phase difference between the current flowing through the armature winding and the back electromotive force waveform generated in the armature winding changes, An electric washing machine with stable performance in which the control means can control the switching means according to the output of the comparison means can be realized.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a circuit diagram of a main part of an inverter device according to this embodiment.

The motor 1 has a configuration in which a rotor is provided inside a stator. The rotor has a configuration in which eight-pole permanent magnets 1a are arranged on the outer periphery of an iron core. Although not particularly shown in the present embodiment, each pole of the permanent magnet 1a is divided, and after being arranged on the iron core so as to have eight poles, resin molding is performed. The stator includes an iron core formed by laminating silicon steel plates having a shape of 12 slots and armature windings 1b, 1b.
c, 1d, and the armature windings 1b to 1d are concentratedly wound around each slot. The armature windings 1b to 1d are formed by three-phase star connection. Note that the configuration of the electric motor is not limited to this, and may be, for example, an outer rotor configuration, the number of poles of the permanent magnet or the number of slots of the stator may be changed, and the armature winding may be changed. A configuration of a distributed winding may be used.

The inverter circuit 2 has a three-phase six-stone configuration with three high-potential-side switching means 2a, 2b, and 2c and three low-potential-side switching means 2d, 2e, and 2f. Supplies full-phase AC power. The switching means 2a to 2f are constituted by a parallel circuit of an IGBT and a reverse connection diode. This embodiment is an example, and the IGBT is replaced with a power transistor or a MOS transistor.
An FET, a thyristor, or the like may be used, or the configuration of the inverter circuit 2 may be a three-phase three-stone or single-phase four-stone.

The control means 3 comprises a microcomputer and a plurality of logic circuits, and includes switching means 2a to 2a.
The on / off state of 2f is set. In this embodiment, the ON period of each of the switching means 2a to 2f is the electrical angle 1
It is set to 20 degrees. First storage means 3a, 3
b is constituted by a memory in the microcomputer. The timer 3c uses a timer in the microcomputer. The first storage means 3a stores ON / OFF states of the switching means 2a to 2f corresponding to the time elapsed from the start of driving of the electric motor 1 outputted by the timer 3c. In the second storage unit 3b, ON / OFF states of the switching units 2a to 2f according to the output of the comparison unit 6 described later are set.

The applied voltage control means 4 is composed of a microcomputer and a logic circuit, like the control means 3, and controls the duty ratio of the switching means 2a to 2f during the ON period. That is, in this embodiment, the average value of the voltage applied to the armature windings 1b to 1d is controlled by performing pulse width modulation (PWM). In this embodiment, in order to reduce noise, PWM
Is set to about 15.625 kHz. However, this is merely an example, and the DC voltage output from the rectifier circuit 2 may be controlled by configuring the rectifier circuit 2 with a booster circuit, a step-down circuit, a step-up / step-down circuit, or the like. May be changed. In this embodiment, the microcomputers constituting the control means 3 and the applied voltage control means 4 are integrated.

The voltage detecting means 5 detects the voltage between the armature windings 1b to 1d and the connection terminal of the inverter circuit 2. In the present embodiment, a voltage dividing circuit 5a, 5b, 5c is provided which is composed of a plurality of resistors and capacitors provided for each terminal.

The comparison means 6 comprises three comparators 6a, 6
b, 6c and a filter circuit 6d. The comparators 6a to 6c compare the output voltages of the voltage dividing circuits 5a to 5c with the reference voltage Vref, and output high or low to the filter circuit 6d. The filter circuit 6d is composed of a plurality of logic circuits, and by latching the output for a predetermined period,
Unnecessary components of the output signals of the comparators 6a to 6c are removed. Note that this is an example, and for example, the comparators 6a to 6c are changed to magnitude comparators and AD
A converter is provided to divide the voltage dividing circuits 5a to 5c and the reference voltage into AD.
The output value may be converted and compared by a magnitude comparator, or the filter circuit 6d may be configured by a microcomputer constituting the control means 3 and the applied voltage control means 4, and the comparator circuit may be operated by the microcomputer. Unwanted components of the output signals 6a to 6c may be removed. In this case, the comparing means is constituted only by the comparator.

The reference voltage setting means 7 is a star neutral connection in which at least three resistors 7a, 7b, 7c are star-connected so as to be three-phase, and the other is connected to the input terminals of the armature windings 1b-1d. The circuit 7d and the virtual neutral point circuit 7d are composed of a voltage dividing circuit 7e composed of a resistor and a capacitor for dividing a neutral point voltage. However, the configuration of the reference voltage setting means 7 is not limited to this. For example, the neutral point voltage of the armature windings 1b to 1d may be used as the reference voltage, or the output voltages of the voltage dividing circuits 5a to 5c may be used. The composite voltage may be used as the reference voltage.

As described above, in the voltage detecting means 5, the comparing means 6, and the reference voltage setting means 7, the magnetic flux linked to the armature windings 1b to 1d changes due to the rotation of the permanent magnet 1a,
Accordingly, the relative position of the permanent magnet 1a with respect to the armature windings 1b to 1c may be detected using the back electromotive force generated in the armature windings 1b to 1d. Therefore, for example, an integrating circuit is connected to the outputs of the voltage detecting means 5 and the reference voltage setting means 7, and the output value of the integrating circuit is compared with the comparing means 6
The reference voltage setting means may not only correspond to the neutral point voltage of the electric motor 1 but may be based on the combined voltage of the remaining two-phase terminals of the armature winding. is there.

The drive circuit 8 has, for example, a push-pull circuit configuration using an NPN transistor and a PNP transistor.
A power of V is supplied, and when the power is off, the voltage of the gate terminal is set to 0V.

Reference numeral 9 denotes an AC power supply to which a rectifier circuit 10 is connected. The rectifier circuit 10 is configured as a voltage doubler rectifier circuit by a series circuit of a diode bridge 10a and two electrolytic capacitors 10b and 10c, and supplies DC power to the inverter circuit 3.

FIG. 2 shows an example of a flowchart for driving the electric motor 1 in the inverter device shown in FIG. FIG. 2 will be described with reference to FIG.

When the operation of the electric motor 1 is started, the block 1
At 1, the start control of the electric motor 1 is performed.

In the start control 11, the control means 3 turns on the switching means 2a, 2e for a predetermined period. At the same time, the applied voltage control means 4 controls the duty ratio of the switching means 2a or 2e so that the average value of the applied voltage of the armature winding becomes a predetermined value. As a result, current flows through the armature windings 1b and 1c, and the teeth (teeth) around which the armature windings 1b and 1c are wound.
, A magnetic field of N pole or S pole is generated. The S and N poles of the permanent magnet 1a are attracted or repelled by this magnetic field, and are fixed at predetermined positions. After a lapse of a predetermined period, a synchronous motor control for driving the electric motor 1 as a synchronous motor is performed in block 12.

When the synchronous motor control 12 is started, the timer 3c counts the elapsed time and outputs the current elapsed time to the first storage means 3a. The ON / OFF state of the switching units 2a to 2f according to the elapsed time output from the timer 3c is set in the first storage unit 3a in advance. Based on the setting of the first storage unit 3a, the control unit 3 switches the switching units 2a to 2f in accordance with the elapsed time from the start of the control.
Is turned on and off, and the motor 1 is driven as a synchronous motor. In the present embodiment, the on / off state of the switching means 2a to 2f is set in the first storage means 3a so that the speed of the electric motor 1 increases with time. At the same time, the applied voltage control means 4 controls the duty ratio of the switching means 2a to 2f during the ON period to increase according to the output of the timer 3c.

In the switching control 14, the applied voltage control means 4 controls the energization ratio of the switching means 2a to 2f so that the average value of the applied voltages of the armature windings 1b to 1d becomes a predetermined value. The control means 3 sets on / off of the switching means 2a to 2f in accordance with the output of the timer 3c as in the synchronous motor control 12, and controls the motor 1 as a synchronous motor. At this time, the on / off state of the switching means 2a to 2f is stored in the first storage means 3 so that the speed of the electric motor 1 increases.
a is set. Accordingly, while the average value of the applied voltages to the armature windings 1b to 1d is constant, the speed of the motor 1 increases, so that the load angle of the motor 1 increases and changes from negative to zero. Here, the load angle is a phase difference between the terminal voltage of the electric motor and the electromotive force induced by the permanent magnet. That is, the phase difference of the lag phase of the armature winding current with respect to the back electromotive force generated in the armature windings 1b to 1c gradually decreases, and the voltage detecting means 5 detects the voltage waveform in the phase near zero voltage of the back electromotive force. In block 15, the control unit 2 controls the switching units 2a to 2f to turn on and off according to the output of the comparison unit 6 in block 15,
The motor 1 can be driven as a brushless DC motor.

In the brushless DC motor control 14, the control means 2 controls the switching means 2 according to the output of the comparison means 6.
On / off control of a to 2f. The switching means 2a to 2d according to the output of the comparison means 6 are stored in the second storage means 3b in advance.
The on / off state of 2f is set, and on / off control of the switching means 2a to 2f is performed based on this setting.
When the rotation direction of the motor 1 is both forward and reverse, it is necessary to set the switching means 2a to 2f for the output of the comparison means 6 for each rotation direction. The applied voltage control means 4 increases the energization ratio of the switching means 2a to 2f from a predetermined value set by the switching control 14 according to the elapsed time output from the timer 3c.

As described above, the switching means 2a-2
switching means 2a to 2d so as to control the energization ratio during the ON period of f to a predetermined value and increase the speed of the motor.
By controlling the on / off of f, the load angle of the motor 1 can be increased, so that the voltage detection means 5 can detect the back electromotive force waveform generated in the armature windings 1b to 1d at a desired phase and stop the motor. It is possible to switch from control as a synchronous motor to control as a brushless DC motor without causing this. This embodiment shows one embodiment of claims 1 and 2 of the present invention. (Embodiment 2) FIG. 3 shows an example of a time chart when the electric motor 1 is driven in the inverter device shown in FIG. (A) has shown the output frequency of the inverter circuit 2 which outputs to the electric motor 1. FIG. (B) shows the average value of the applied voltage of the armature windings 1b to 1d controlled by the applied voltage control means 4.

FIG. 3 will be described with reference to FIGS.
When the operation of the electric motor 1 is started at t0, t0 to t1
During the period, the switching means 2a and 2e are turned on by the applied voltage v0 to supply power to the armature windings 1b and 1c. As a result, an N-pole or S-pole magnetic field is generated in the armature windings 1b and 1c, the S-pole and the N-pole of the permanent magnet 1a are attracted, and the relative position of the permanent magnet 1a with respect to the stator is determined.

After t1, the synchronous motor control 12 is performed to drive the motor 1 as a synchronous motor. During the period from t1 to t2, the control unit 3 sets the first storage unit 3a
The switching means 3a to 3f are controlled on the basis of the setting of, and the output frequency of the inverter circuit 3 is increased. The applied voltage control means 4 controls the energization ratio of the switching means 2a to 2f so that the average value of the applied voltages of the armature windings 1b to 1d increases.

From t2, the switching control 1 shown in FIG.
Perform 4. At t2, the output frequency of the inverter circuit 2 becomes the predetermined value f1. That is, when the motor 1 is not out of synchronization, the motor 1 is rotating at a speed proportional to the predetermined frequency f1. The control unit 3 controls the switching units 2a to 2f to be on / off based on the setting of the first storage unit 3a, and increases the output frequency of the inverter circuit 2. At the same time, the applied voltage control means 4
The energization ratio of the switching means 2a to 2f is controlled so that the average value of the applied voltage d becomes v1. In this embodiment,
The period from t2 to t3 is a period of 360 electrical degrees.
During this period, the load angle of the electric motor 1 gradually increases,
It changes from negative to zero. At the same time, the lag phase of the armature winding current with respect to the back electromotive force generated in the armature winding is gradually corrected. As a result, the voltage detecting means 5 can detect the phase of the back electromotive force near zero voltage, and the comparing means 6 can output an accurate position detection signal to the control means 3.

From t3, the brushless DC shown in FIG.
Perform motor control. The control means 3 controls on / off of the switching means 2a to 2f based on the setting of the second storage means according to the logic output from the comparison means 6 at t2. The applied voltage control means 4 controls the switching means 2a to 2f so that the average value of the applied voltages to the armature windings 1b to 1c increases.
Is controlled. Therefore, the motor 1 is
It will be driven as a C motor.

This embodiment shows a second embodiment of the present invention. (Embodiment 3) FIG. 4 shows another example of a time chart when the electric motor 1 is driven in the inverter device shown in FIG. (C) shows the output frequency of the inverter circuit 2 that outputs to the electric motor 1. (D) shows the average value of the applied voltages of the armature windings 1b to 1d controlled by the applied voltage control means 4.

FIG. 4 will be described with reference to FIGS.
When the operation of the electric motor 1 is started at t0, t0 to t1
During the period, the switching means 2a and 2e are turned on by the applied voltage v0 to supply power to the armature windings 1b and 1c. As a result, an N-pole or S-pole magnetic field is generated in the armature windings 1b and 1c, the S-pole and the N-pole of the permanent magnet 1a are attracted, and the relative position of the permanent magnet 1a with respect to the stator is determined.

From t1, the synchronous motor control 12 is performed to drive the motor 1 as a synchronous motor. During the period from t1 to t2, the control unit 3 sets the first storage unit 3a
The switching means 3a to 3f are controlled on the basis of the setting of, and the output frequency of the inverter circuit 3 is increased. The applied voltage control means 4 controls the energization ratio of the switching means 2a to 2f so that the average value of the applied voltages to the armature windings 1b to 1d increases in proportion to the elapsed time output from the timer 3c.

From t2, the switching control 1 shown in FIG.
Perform 4. At t2, the output frequency of the inverter circuit 2 becomes the predetermined value f1. That is, when the motor 1 is not out of synchronization, the motor 1 is rotating at a speed proportional to the predetermined frequency f1. During the period from t2 to t3, the control unit 3 controls the switching units 2a to 2f to turn on and off based on the setting of the first storage unit 3a,
To increase the output frequency. At the same time, the applied voltage control means 4
Indicates that the average value of the applied voltages of the armature windings 1b to 1d is a predetermined value v
The energization ratio of the switching means 2a to 2f is controlled so as to increase from 1 in proportion to the elapsed time output from the timer 3c. The rate of increase, that is, the proportionality constant, at this time is set smaller than that in the case of the synchronous motor control 12. During this period, the load angle of the electric motor 1 gradually increases, and the lag phase of the armature winding current with respect to the back electromotive force generated in the armature winding is gradually corrected. That is, the time ratio of the phase change is smaller than that of the second embodiment of the present invention, the voltage detecting means 5 can detect the phase near the zero voltage of the back electromotive force for a long time, and the comparing means 6 has an accurate position. A detection signal can be output to the control means 3, and the time required for the load angle of the electric motor 1 to become excessive and the lag phase to advance to the phase can be prolonged.

If the control means 3 overlooks the position detection signal from the comparison means 6, the motor 1 may be stopped out of synchronization. In this embodiment, the position detection signal can be obtained over a long period of time. It is considered that this also works effectively in improving the reliability of the device.

From t3, the brushless DC shown in FIG.
Perform motor control. The control means 3 controls on / off of the switching means 2a to 2f based on the setting of the second storage means according to the logic output from the comparison means 6 at t2. The applied voltage control means 4 controls the switching means 2a to 2f so that the average value of the applied voltages to the armature windings 1b to 1c increases.
Is controlled. Therefore, the motor 1 is
It will be driven as a C motor.

As described above, in this embodiment, the control means 3
Switching means 2 to increase the speed of motor 1
a to 2f, and the applied voltage control means 4 controls the energization ratio of the switching means 2a to 2f so that the average value of the applied voltages of the armature windings 1b to 1d increases. The difference in the lag phase of the armature winding current with respect to the back electromotive force generated in 1b to 1d can be gradually reduced. Accordingly, the period until the phase of the armature winding current with respect to the back electromotive force changes from the lag phase to the leading phase is lengthened to prevent the motor 1 from being out of synchronization, and the voltage detecting means 5 determines whether the back electromotive force is desired. Is longer, the motor 1 can be reliably controlled by the output of the comparing means 6. (Embodiment 4) FIG. 5 shows another example of a time chart when the electric motor 1 is driven in the inverter device shown in FIG. (E) shows the output frequency of the inverter circuit 2 that outputs to the electric motor 1. (F) shows the average value of the applied voltages of the armature windings 1b to 1d controlled by the applied voltage control means 4.

FIG. 5 will be described with reference to FIGS.
When the operation of the electric motor 1 is started at t0, t0 to t1
During the period, the switching means 2a and 2e are turned on by the applied voltage v0 to supply power to the armature windings 1b and 1c. As a result, an N-pole or S-pole magnetic field is generated in the armature windings 1b and 1c, the S-pole and the N-pole of the permanent magnet 1a are attracted, and the relative position of the permanent magnet 1a with respect to the stator is determined.

After t1, the synchronous motor control 12 is performed to drive the motor 1 as a synchronous motor. During the period from t1 to t2, the control unit 3 sets the first storage unit 3a
The switching means 3a to 3f are controlled on the basis of the setting of, and the output frequency of the inverter circuit 3 is increased. The applied voltage control means 4 controls the energization ratio of the switching means 2a to 2f so that the average value of the applied voltages to the armature windings 1b to 1d increases in proportion to the elapsed time output from the timer 3c.

From t2, the switching control 1 shown in FIG.
Perform 4. At t2, the output frequency of the inverter circuit 2 becomes the predetermined value f1. That is, when the motor 1 is not out of synchronization, the motor 1 is rotating at a speed proportional to the predetermined frequency f1. During the period from t2 to t3, the control unit 3 controls the switching units 2a to 2f to turn on and off such that the output frequency of the inverter circuit 2 becomes the predetermined value f1. At the same time, the applied voltage control means 4 controls the armature windings 1b to 1d
The energization ratio of the switching means 2a to 2f is controlled so that the average value of the applied voltage decreases from the predetermined value v1 in proportion to the elapsed time output from the timer 3c. During this period, the load angle of the electric motor 1 gradually increases, and the lag phase of the armature winding current with respect to the back electromotive force generated in the armature winding is gradually corrected. As a result, the voltage detecting means 5 can detect the phase of the back electromotive force near zero voltage, and the comparing means 6 can output an accurate position detection signal to the control means 3.

From t3, the brushless DC shown in FIG.
Perform motor control. The control means 3 controls on / off of the switching means 2a to 2f based on the setting of the second storage means according to the logic output from the comparison means 6 at t2. The applied voltage control means 4 controls the switching means 2a to 2f so that the average value of the applied voltages to the armature windings 1b to 1c increases.
Is controlled. Therefore, the motor 1 is
It will be driven as a C motor.

As described above, in this embodiment, the control means 3
Controls on / off of the switching means 2a to 2f so that the speed of the motor 1 becomes a predetermined value, and the applied voltage control means 4 controls the switching means 2a so that the average value of the applied voltages of the armature windings 1b to 1d decreases. Since the current-carrying ratio is controlled to 2f, the difference in the lag phase of the armature winding current with respect to the back electromotive force generated in the armature windings 1b to 1d can be reduced. Accordingly, the lag phase of the armature winding current with respect to the back electromotive force can be reduced at a predetermined speed, so that the motor 1 is always driven as a brushless DC motor at a speed at which sufficient back electromotive force is detected by the voltage detecting means 5. You can switch to This embodiment shows a fourth embodiment of the present invention. (Embodiment 5) FIG. 6 is a circuit diagram of a main part of an inverter device which is another example different from FIG.

The judging means 21 and the switching means 22 correspond to the control means 3
And a microcomputer constituting the applied voltage control means 4. Therefore, in this embodiment, the control unit 3, the applied voltage control unit 4, the determination unit 21, and the switching unit 2
The microcomputers constituting 2 are integrated. The determination means 21 compares the on / off setting of the switching means 2a to 2f output from the first storage means 3a with the on / off setting of the switching means 2a to 2f output from the second storage means 3b. Are output to the switching means 22 as to whether or not. Other configurations are the same as those in FIG.

The switching means 22 receives the output of the judging means 21 and outputs to the driving circuit 8 the switching means 2a to 2f
Is switched between the setting by the first storage means 3a and the setting by the second storage means 3b.

Note that this is only an example, and the judging means 21 may be constituted by a logic circuit such as a 6-input EXOR circuit and a 6-input AND circuit, and the switching means 22 may be a commercially available data selector IC. May be used.

FIG. 7 shows a flowchart of the switching control 13 in FIG.

FIG. 7 will be described with reference to FIG. When the switching control 13 is started, at block 31 the determination means 21
Initialize output low. In block 32, the applied voltage control means switches the switching means 2a to 2f so that the average value of the applied voltages of the armature windings 1b to 1d becomes a predetermined value v1.
Is PWM controlled. In the present example, the switching control 13
Until the operation is completed, the average value of the applied voltages to the armature windings 1b to 1d remains at the predetermined value v1. In block 33, the second storage unit 3 b outputs the on / off setting of the switching units 2 a to 2 f to the switching unit 22 according to the output of the comparison unit 6. At this time, the output of the judgment means 21 is low, and the switching means 22 outputs to the drive circuit 8 the on / off state of the switching means set by the first storage means 21. In block 34, on / off control of the switching means 2a to 2f is performed so that the output frequency of the inverter circuit 3 increases. In the present embodiment, the first storage unit 3a
The on / off state of the switching means 2a to 2f corresponding to the elapsed time output from the timer 3c is stored in advance, and the output frequency of the inverter circuit 3 is increased based on this setting. In block 35, the first storage unit 3a and the second storage unit 3b are determined by the determination unit 21.
Are determined to be the same, and if they are the same, a high is output to the switching means 22. If the output of the determination means 21 is high, the switching means 22 outputs the switching means 2a to
The on / off setting of 2f is output to the drive circuit 8,
The switching control 13 ends. When the output of the determination means 22 is low, the output frequency of the inverter circuit 3 is continuously increased until the output becomes high.

Therefore, in this embodiment, FIGS.
The period from t2 to t3 in the time chart shown in FIG. 5 is not constant, but fluctuates according to the output of the determination means 21.

As described above, in this embodiment, the on / off state of the switching means 2a to 2f set by the first storage means 3a and the timer 3c, and the setting by the second storage means 3b and the comparison means 6 are set. Switching means 2a-2
Since the determination means 21 for determining whether the load angle of the motor 1 is appropriate by comparing the on / off states of f is provided, the output of the determination means 21 ensures that the motor 1 is controlled as a synchronous motor. From the control to the brushless DC motor can be realized. This embodiment shows one embodiment of claims 5 and 6 of the present invention. (Embodiment 6) FIG. 8 is a block diagram of a main part of an electric washing machine using the inverter device of FIG. 6, and shows an embodiment of the electric washing machine according to claim 8 of the present invention. As shown in FIG. 8, the water receiving tub 31 is provided with a washing / dehydrating tub 33 rotatably provided with a stirring blade 32 rotatably provided on an inner bottom thereof, and is suspended from a washing machine main body 35 by a suspension 34.
The speed reduction mechanism 36 is provided at the bottom of the water receiving tank 31,
The motor 1 is provided below the speed reduction mechanism 36 for transmitting power to the washing and dewatering tub 33. The water supply valve 37 supplies water to the washing and dewatering tub 33, and the drain valve 38 drains washing water and the like in the washing and dehydration tub 33. The control board 39 includes, in addition to the inverter device shown in FIG. 6, a drive circuit for the water supply valve 37 and the drain valve 38, an operation display unit for the user to operate, and the like.

The speed reduction mechanism 36 has a planetary gear, and when the stirring blade 32 is driven to rotate, the sun gear is driven by the output shaft of the electric motor 1 and the rotation of the planetary gear is transmitted to the stirring blade 32. , And reduces the output torque of the electric motor 1 to 6 times. In the case of rotating and driving the washing and dewatering tub 33 such as dehydration, the speed reduction mechanism 36 is separated from the output shaft of the electric motor 1 by a clutch mechanism (not shown), and the washing and dewatering tub 33 is directly driven by the electric motor 1.
However, the present invention is not particularly limited to such a configuration of the motor. For example, a configuration in which the power of the motor 1 is transmitted to the reduction mechanism 36 by a belt, or the configuration of the motor 1 without the reduction mechanism 36 is provided.
May be directly transmitted to the stirring blade 32.

As described above, in the electric washing machine of this embodiment,
Since it is not necessary to provide the motor 1 with a position detecting means constituted by a Hall IC or the like, there is no need to connect the position detecting means and the control board 39 by wiring, and wiring costs and the like are eliminated and cost can be reduced. it can. In addition, since it is not necessary to provide a location for installing the position detecting means, the motor 1
Can be reduced in size, and as a result, the height of the electric washing machine can be reduced.

FIG. 9 shows an example of a time chart when the stirring blade 32 of the electric washing machine shown in FIG. (G) shows the output frequency of the inverter circuit 2 that outputs to the electric motor 1. (H) shows the average value of the applied voltage of the armature windings 1b to 1d controlled by the applied voltage control means 4.

FIG. 9 will be described with reference to FIGS. When the operation of the motor 1 is started at t0, t0 to t0
During the period of t1, the switching means 2a and 2
e is turned on to supply power to the armature windings 1b and 1c. As a result, an N-pole or S-pole magnetic field is generated in the armature windings 1b and 1c, the S-pole and the N-pole of the permanent magnet 1a are attracted, and the relative position of the permanent magnet 1a with respect to the stator is determined.

After t1, the motor 1 is driven as a synchronous motor. In the period from t1 to t2, the control unit 3 controls the switching units 3a to 3f based on the setting of the first storage unit 3a, and increases the output frequency of the inverter circuit 2. The applied voltage control means 4 includes the armature windings 1b to
The energization ratio of the switching means 2a to 2f is controlled so that the average value of the applied voltage 1d increases. As a result, a rotating magnetic field proportional to the output frequency of the inverter circuit 3 is generated in the armature windings 1b to 1d, and the rotor is rotationally driven by the electromagnetic force between the permanent magnets 1a. In the electric washing machine, the load of the electric motor 1 is constantly changed because the stirring blade 32 is rotationally driven to stir the cloth to be washed. Therefore, when controlling the motor 1 as a synchronous motor, the average value of the applied voltages to the armature windings 1b to 1d needs to be sufficiently large so that the motor 1 does not lose synchronization.

From time t2, the switching control shown in FIG. 7 is performed. At t2, the output frequency of the inverter circuit 2 becomes the predetermined value f1. That is, when the motor 1 is not out of synchronization, the motor 1 is rotating at a speed proportional to the predetermined frequency f1. The control unit 3 controls the switching units 2a to 2f to be on / off based on the setting of the first storage unit 3a, and increases the output frequency of the inverter circuit 2.
At the same time, the applied voltage control means 4 controls the energization ratio of the switching means 2a to 2f so that the average value of the applied voltages of the armature windings 1b to 1d becomes v1. At the same time, the determination means 21 compares the output of the first storage means 3a with the output of the second storage means 3b. As described above, when the switching control is started,
The load angle of the motor 1 increases, and the phase of the armature winding current with respect to the back electromotive force generated in the armature winding is gradually corrected from the lagging phase to the leading phase direction. As a result, the voltage detecting means 5 can detect the phase of the back electromotive force near zero voltage, and the comparing means 6 can output an accurate position detection signal to the second storage means 3b. Switching means 2a to 2f output from the second storage means 3b
And the on / off states of the switching means 2a to 2f output from the first storage means 3a coincide with each other, and the judging means 21 judges that they coincide with each other, and ends the switching control.

After t3 when the switching control is completed, the brushless DC motor control shown in FIG. 2 is performed. The control means 3 controls on / off of the switching means 2a to 2f based on the setting of the second storage means 3b according to the logic output from the comparison means 6. Immediately after the switching control ends, the applied voltage control means 4 switches the switching means 2a to 2a so that the average value of the applied voltage of the armature windings 1b to 1c increases from a predetermined value v1.
PWM control is performed on the energization ratio of f. Therefore, the electric motor 1 is driven as a brushless DC motor.

As described above, in a device such as an electric washing machine in which the stirring blade 32 is rotationally driven to constantly change the state of the object to be washed, and as a result, the load of the electric motor 1 constantly changes. By controlling so as to increase the load angle of the electric motor 1 and determining the degree of the load angle of the electric motor 1 by the determination means 21, it is possible to reliably switch the electric motor 1 to control as a brushless DC motor. In the case of a small inertia such as the agitating blade 21, the period during which the motor 1 is rotationally driven by the inertial force is short, so that when the power supply is stopped, the motor 1 immediately stops operating.
By providing the determination means 21, the electric motor 1 can be controlled as a brushless DC motor without stopping power supply. Further, as soon as the output of the judgment means 21 is received, the applied voltage control means 4 performs PWM control on the duty ratio of the switching means 2a to 2f so as to increase the average value of the applied voltages of the armature windings 1b to 1d. Motor 1 is brushless DC
Immediately after switching to the control as a motor, it is possible to suppress the load from becoming large due to the cloth being stuck to the laundry and the speed of the electric motor 1 being reduced. This embodiment shows one embodiment of the inverter device and the electric washing machine according to claims 6, 7 and 8 of the present invention.

[0076]

As described above, according to the first aspect of the present invention, a motor having a permanent magnet in a rotor and an armature winding in a stator, and an inverter connected to the motor. Control means for controlling a circuit and a switching means constituting the inverter circuit, applied voltage control means for controlling an applied voltage of the armature winding, voltage detection means for detecting a terminal voltage of the armature winding, Comparing means for comparing the output voltage of the voltage detecting means with a reference voltage, and reference voltage setting means for setting the reference voltage, wherein the control means is driven as a synchronous motor when starting the motor, And the switching means is controlled in accordance with the output of the comparison means, so that the load of the motor fluctuates while the motor is driven as a synchronous motor and the armature windings Even if the detected current has a lag phase with respect to the back electromotive force generated in the armature winding, the lag phase is corrected in the leading direction, and the voltage detecting means detects the zero voltage of the back electromotive force generated in the armature winding. And a waveform in the range of a phase lag of 30 degrees from the motor can be detected, and the motor can be reliably driven as a brushless DC motor based on the back electromotive force.

According to the second aspect of the present invention,
In the invention according to claim 1, the control means controls on / off of the switching means so as to increase the speed of the motor, and the applied voltage control means controls the applied voltage of the armature winding to a predetermined value. Thus, since the load angle is increased, the motor can be controlled as a brushless DC motor based on the back electromotive force generated in the armature winding while accelerating the motor.

According to the third aspect of the present invention,
In the invention according to claim 1, the applied voltage control means controls the applied voltage of the armature winding to increase at a small increase rate as compared with the increase rate of the motor speed,
Since the load angle is increased, it is possible to control the motor as a brushless DC motor based on the back electromotive force generated in the armature winding while accelerating the motor, and to drive the motor as a synchronous motor. This has the effect of preventing loss of synchronization during a certain period, especially immediately before control as a brushless DC motor.

According to the invention described in claim 4 of the present invention,
In the invention described in claim 1, the control means controls on / off of the switching means so that the speed of the motor becomes a predetermined value, and the applied voltage control means controls the applied voltage of the armature winding to decrease. Thus, since the load angle is increased, even if the load fluctuates while the motor is being driven as a synchronous motor, the motor is reliably reduced at a predetermined speed to the back electromotive force generated in the armature winding. This has the effect that it can be controlled as a brushless DC motor based on this.

According to the fifth aspect of the present invention,
The invention according to any one of claims 1 to 4, further comprising a determination unit for determining that the load angle is within a predetermined range, receiving the output of the determination unit, and turning on / off the switching unit according to the output of the comparison unit. Since the control is performed, the motor is controlled as a brushless DC motor in a state where the voltage detection means can reliably detect the predetermined phase of the back electromotive force waveform generated in the armature winding, and the inverter with stable performance This has the effect of realizing the device.

According to the invention described in claim 6 of the present invention,
In the invention according to claim 5, the determination means compares the on / off state of the switching means according to the output signal of the comparison means with the on / off state of the switching means output by the control means. When switching the control of the electric motor from the control as a synchronous motor to the control as a brushless DC motor, there is an effect that it is possible to realize a smooth switching without having to change the on / off state of the switching means.

According to the seventh aspect of the present invention,
In the invention according to any one of claims 5 and 6, the applied voltage control means is configured to perform control so as to increase the applied voltage to the armature winding upon receiving the output of the determination means. When switching from control as a synchronous motor to control as a brushless DC motor, the present invention has an effect of suppressing a decrease in the speed of the motor.

According to the invention described in claim 8 of the present invention,
In the invention according to any one of claims 1 to 7, since the inverter device according to any one of claims 1 to 7 is provided, the load of the electric motor is reduced due to a change in the amount of the laundry to be washed of the electric washing machine. Changes, and even if the phase difference between the current flowing through the armature winding and the back electromotive force waveform generated in the armature winding fluctuates, the control means reliably controls the switching means in accordance with the output of the comparison means. This has the effect of realizing an electric washing machine with stable performance that can be controlled.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a main part of an inverter device according to first to fourth embodiments of the present invention.

FIG. 2 is a drive control flowchart of the motor of the inverter device according to the first embodiment of the present invention;

FIG. 3 is a drive control time chart of a motor of an inverter device according to a second embodiment of the present invention.

FIG. 4 is a drive control time chart of a motor of an inverter device according to a third embodiment of the present invention.

FIG. 5 is a drive control time chart of an electric motor of an inverter device according to a fourth embodiment of the present invention.

FIG. 6 is a circuit diagram of a main part of an inverter device according to a fifth embodiment of the present invention.

FIG. 7 is a switching control flowchart of the inverter device.

FIG. 8 is a main block diagram of an electric washing machine according to a sixth embodiment of the present invention.

FIG. 9 is a drive control flowchart of the electric motor at the time of driving the stirring blades of the electric washing machine.

FIG. 10 is a circuit diagram of a main part of a conventional inverter device.

FIG. 11 is a drive control time chart of a motor of a conventional inverter device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 1a Permanent magnet 1b-1d Armature winding 2 Inverter circuit 2a-2f Switching means 3 Control means 4 Applied voltage control means 5 Voltage detection means 6 Comparison means 7 Reference voltage setting means

Continued on the front page (72) Inventor Yasudo Kobayashi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (Reference) 5H007 AA06 BB06 CA01 CB05 DA06 DB01 DB12 DC05 EA02 GA01 5H560 AA10 BB04 BB12 DA13 DB13 DC13 EB01 EC10 GG04 HA04 JJ12 SS07 TT01 TT08 TT15 UA06 XA04 XA12

Claims (8)

[Claims] An electric motor having a permanent magnet in a rotor and an armature winding in a stator, an inverter circuit connected to the electric motor, and control means for controlling a switching means constituting the inverter circuit; An applied voltage control unit that controls an applied voltage of the armature winding, a voltage detection unit that detects a terminal voltage of the armature winding, a comparison unit that compares an output voltage of the voltage detection unit with a reference voltage, A reference voltage setting unit for setting a reference voltage; wherein the control unit is driven as a synchronous motor at the time of starting the motor, and thereafter increases the load angle and controls the switching unit according to an output of the comparison unit. Inverter device. The control means controls on / off of the switching means so as to increase the speed of the electric motor, and the applied voltage control means controls the applied voltage of the armature winding to a predetermined value, thereby controlling the load. The inverter device according to claim 1, wherein the angle is increased. 3. The load voltage control device according to claim 1, wherein the applied voltage control means increases the load angle by controlling the applied voltage of the armature winding to increase at a smaller increase rate than the increase rate of the motor speed. 3. The inverter device according to claim 1. 4. The control means controls on / off of the switching means so that the speed of the motor becomes a predetermined value, and the applied voltage control means controls the applied voltage of the armature winding to be reduced, so that the load angle is controlled. The inverter device according to claim 1, wherein 5. The apparatus according to claim 1, further comprising: a determination unit configured to determine that the load angle is within a predetermined range, wherein the switching unit is controlled to be turned on / off in response to an output of the determination unit. The inverter device according to any one of the above. 6. The inverter device according to claim 5, wherein the judging means compares the on / off state of the switching means according to the output signal of the comparing means with the on / off state of the switching means output from the control means. 7. The inverter device according to claim 5, wherein the applied voltage control means controls so as to increase the applied voltage to the armature winding upon receiving the output of the determination means. 8. An electric washing machine provided with the inverter device according to claim 1.