JP2001259281A - Electric washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of increasing the height of a motor due to the arrangement of a position detection means made up of a Hall IC to detect a relative position of a permanent magnet in relation to a stator in the motor and costliness due to the need for wiring to connect the position detection means and a control means in a vacuum cleaner provided with a motor having a permanent magnet. SOLUTION: This electric washing machine detects a counter electromotive force of armature windings 4a to 4c forming a motor 4 and rotationally drives the motor 4 by providing the machine with an inverter circuit 3 comprised of switching means 3a to 3f, a voltage detection means 5 to detect voltage of the motor 4 connected to the inverter circuit 3 and input terminals U, V and W of the motor 4, a control means 6 to turn on or off the switching means 3a to 3f by output signals of the voltage detection means 5, and a driving circuit 7 to drive the switching means 3a to 3f by on/off signals of the control means 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric washing machine driven by an electric motor connected to an output of an inverter.

[0002]

2. Description of the Related Art FIG. 13 shows a configuration of an inverter device provided in a conventional electric washing machine. The AC power supply 1 is connected to a rectifier circuit 2, which supplies DC power to an inverter circuit 3, and an output terminal of the inverter circuit 3 is connected to a motor 4.

The rectifier circuit 2 is configured as a voltage doubler rectifier circuit by a series circuit of a diode bridge 2a and two capacitors 2b and 2c for smoothing.

[0004] The inverter circuit 3 has a three-phase six-stone structure with switching means 3a, 3b, 3c on the high potential side and switching means 3d, 3e, 3f on the low potential side. Each of the switching means 3a to 3f is constituted by a parallel circuit of an IGBT and a reverse connection diode capable of supporting high-frequency switching and large current capacity.

The electric motor 4 comprises a rotor 4d having a permanent magnet and a stator having armature windings 4a, 4b, 4c. The armature windings 4a to 4c have a three-phase star connection configuration. Note that the stator is not particularly illustrated.

The position detecting means 61 detects the relative positions of the permanent magnet constituting the rotor 4a and the stator 4b, and comprises three Hall ICs 61a, 61b and 61c. The Hall ICs 61a to 61c detect the direction of the field of the permanent magnet and output high or low to the control means 62.

The control means 62 is constituted by a microcomputer or a logic circuit. According to the combination of the logic of the output signal of the position detection means 61 and the direction of rotation, a predetermined switching means is turned on / off and the three-phase power is supplied to the motor 4. An on / off signal is output to the drive circuit 7 so as to supply the IGBT to the IGBT.

The drive circuit 7 has, for example, a push-pull circuit configuration using an NPN transistor and a PNP transistor. When the drive circuit 7 is on, 15 V is applied to the gate terminal of the IGBT.
Is supplied, and when the power is off, the voltage of the gate terminal is set to 0V.

FIG. 14 shows an electric washing machine provided with the inverter device shown in FIG. The water receiving tub 11 is provided with a washing and dewatering tub 13 rotatably provided with a stirring blade 12 rotatably provided on an inner bottom thereof, and is suspended from a washing machine body 15 by a suspension 14. The speed reduction mechanism 16 is provided at the bottom of the water receiving tank 11, and transmits power to the stirring blade 12 and the washing and dewatering tank 13. The electric motor 4 is provided below the speed reduction mechanism 16. The motor 4 has three Hall ICs 61a to 6
The position detecting means 61 constituted by 1c is disposed on the upper part. The water supply valve 17 supplies water to the washing and dewatering tub 13, and the drainage valve 18 drains washing water and the like in the washing and dehydration tub 13.

The control device 71 is provided with the inverter device shown in FIG. 13, the output of which is connected to the electric motor 4, and switches the predetermined switching means 3 a to 3 f in accordance with the output logic of the position detecting means 61. On / off control, motor 4
Is driven to rotate. The control device 71 also controls the water supply valve 17 and the drain valve 18.

Here, the speed reduction mechanism 16 has a planetary gear. When the stirring blade 12 is driven to rotate, the sun gear is driven by the shaft of the electric motor 4 to rotate the planetary gear.
, The output torque of the electric motor 4 is reduced by a factor of six and the output torque of the electric motor 4 is converted into a factor of six. In the process of rotating the washing and dewatering tub 13 such as dehydration, although not particularly shown, the speed reduction mechanism 16 is connected to the electric motor 4 by a clutch mechanism.
And the washing and dewatering tub 13 is directly driven by the electric motor 7 without deceleration.

As described above, in an electric washing machine in which an electric motor having a permanent magnet on a rotor is driven by an inverter circuit, a position formed by a Hall element or a Hall IC for detecting the magnetic pole of the permanent magnet provided on the rotor. Detecting means for detecting a relative position of the rotor and the stator based on an output signal of the position detecting means, controlling on / off of switching means constituting the inverter circuit, rotating and driving the electric motor, and washing and dewatering. Was to do.

[0013]

As described above, in the conventional electric washing machine, since the electric motor is provided with the position detecting means constituted by a plurality of Hall ICs or Hall elements,
It is necessary to wire between the control means and the position detection means to communicate power supply for driving the position detection means and output signals of the position detection means, and in the electric washing machine, a motor is provided at a lower part. Therefore, there is a problem that the wiring becomes long.

Further, since a certain amount of space is required for arranging the position detecting means, the height of the motor is correspondingly increased, and the effect of making the motor thinner is particularly large. It had the following.

Further, it is necessary to take noise countermeasures in order to prevent electromagnetic noise from the electric motor from being put on a signal line from which the position detecting means transmits an output signal to the control means, thereby preventing malfunction of the inverter device. There was a problem that there is.

Further, there has been a problem that the cost is increased by performing a waterproofing treatment so that water does not enter into the connector for connecting the position detecting means and the wiring due to water splash or the like.

The present invention solves the above-mentioned problems of the conventional electric washing machine, and determines the relative position of the rotor and the stator by using a back electromotive force generated in an armature winding constituting the electric motor. An object of the present invention is to eliminate a position detecting means constituted by a Hall IC or a Hall element by detecting.

[0018]

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 on / off of a switching means constituting an inverter circuit, and voltage detection means for detecting a back electromotive force generated in an armature winding of the electric motor during rotation driving of the rotor, wherein the control means includes: An inverter for controlling the switching means to be turned on and off by an output of the voltage detecting means in accordance with a rotation direction of the motor, wherein a part of the back electromotive force generated in the armature winding is a terminal voltage of the motor. Therefore, the relative position of the rotor and the stator of the motor can be detected without providing the motor with a position detecting means constituted by a Hall IC. It can be.

Furthermore, since the wiring between the position detecting means and the control means can be eliminated and the height of the electric motor can be reduced, the electric washing machine can be made compact at low cost.

[0020]

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 on / off of a switching means constituting a circuit, and voltage detection means for detecting a back electromotive force generated in an armature winding of an electric motor during rotation driving of the rotor, wherein the control means is An inverter device for controlling the switching means to be turned on and off by an output of the voltage detecting means in accordance with the rotation direction of the motor, wherein a part of the back electromotive force generated in the armature winding is determined by a terminal voltage of the motor. Detecting the relative position of the rotor and the stator of the electric motor without providing the electric motor with position detecting means constituted by a Hall IC. Can, or eliminate wiring between said position detecting means and said control means, it is possible to reduce the height of the motor can be made compact electric washing machine at a low cost.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a current detecting means for detecting a current corresponding to a current flowing through the armature winding of the electric motor. According to the outputs of the current detection means and the voltage detection means,
The on / off timing of the switching means is delayed by a predetermined phase, whereby the phase of the back electromotive force waveform generated in the armature winding due to the current flowing in the armature winding is changed by the permanent magnet of the rotor. Even if the phase is advanced from the position, the current position of the permanent magnet of the rotor can be estimated, and the switching means can be turned on and off almost in synchronization with the position of the permanent magnet of the rotor.

Thus, the switching timing can be adjusted so that the ratio of the output torque per current of the electric motor is maximized, so that the operable region of the electric motor can be expanded, and various washing methods can be performed by the electric washing machine. Can be realized. Further, the efficiency of the electric washing machine can be increased.

According to a third aspect of the present invention, in the first aspect of the present invention, there is provided a speed detecting means for detecting a speed of the electric motor based on an output of the voltage detecting means. The on / off timing of the switching means is changed by a predetermined phase according to the output of the voltage detecting means. In a motor having a permanent magnet in the rotor, if the current flowing through the armature winding is constant, the phase of the back electromotive force generated in the armature winding due to the rotation speed of the motor and the permanent magnet of the rotor Has the characteristic that the phase varies. Basically, as compared with the phase of the permanent magnet, the lower the rotational speed of the electric motor, the more advanced the phase.

In general, the magnitude and frequency of the back electromotive force generated in the armature winding are proportional to the rotation speed of the motor, and the lower the speed, the lower the back electromotive force and the lower the frequency. Therefore, if the voltage detection means has a configuration having a low-pass filter or a high-pass filter, the phase of the output signal of the voltage detection means is synchronized with the position of the permanent magnet of the rotor by the rotation speed of the motor due to the frequency characteristic. No longer.

If the voltage detecting means compares the back electromotive force generated in the armature winding with a predetermined reference voltage, the magnitude of the back electromotive force generated in the armature winding depends on the magnitude of the back electromotive force generated in the armature winding. The phase to be detected fluctuates.

Therefore, the rotational speed of the electric motor is detected by the speed detecting means, and the control means changes the on / off timing of the switching means by a predetermined phase in accordance with the detected speed of the speed detecting means. Thus, the electric motor can be driven to rotate. Thus, even in an electric washing machine having a plurality of rotation speed conditions, the electric motor can be reliably driven to rotate, and the washing and dewatering performance can be satisfied.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a speed detecting means for detecting a speed of the motor by an output of the voltage detecting means, and a current flowing through an armature winding of the motor. A current detection unit for detecting a corresponding current; and the control unit changes the on / off timing of the switching unit by a predetermined phase according to the outputs of the speed detection unit, the current detection unit, and the voltage detection unit. Things.

Therefore, even if the phase of the back electromotive force generated in the armature winding changes due to a change in the rotation speed of the motor or the current flowing in the armature winding, the phase of the permanent magnet of the rotor changes. The switching means can be turned on and off substantially in synchronization with the motor, so that the operable region of the motor can be expanded.

Thus, even in an electric washing machine having a plurality of washing conditions, the electric motor can be surely driven to rotate, and the washing and dewatering performance can be satisfied. Further, since the operable region of the electric motor can be expanded even when the amount of laundry increases, an electric washing machine which can sufficiently cope with the problem can be realized.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the control means includes a first half of a switching period of the switching means.
2, the regenerative current period generated when the switching means is turned off can be kept constant regardless of whether the switching means is on the high potential side or the low potential side. The voltage detecting means can detect the back electromotive force generated in the armature winding without being affected by the switching means, so that the control means can easily control the on / off timing of the switching means. And a low-cost inverter device can be realized.

Further, since the period of the regenerative current is lengthened, the change in the current flowing through the armature winding can be reduced, and the motor can be rotationally driven with low noise. Therefore, a low noise or low cost or compact electric washing machine can be realized.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the control means includes a second half of a switching period of the switching means.
In the second aspect, the conduction ratio is controlled, and the regenerative current period generated when the switching means is turned off can be made constant regardless of whether the switching means is at the high potential side or the low potential side, as in the fifth aspect. . Further, since the regenerative current period is shortened, the period for detecting the back electromotive force generated in the armature winding can be lengthened, and the voltage detecting means can reliably detect the back electromotive force. it can.

Therefore, the control means can easily control the on / off timing of the switching means, and a low-cost and highly reliable electric washing machine can be realized.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the voltage detecting means divides a terminal voltage of an armature winding constituting the motor. Circuit, the voltage dividing circuit is configured to switch the voltage dividing ratio according to the output of the speed detecting means, and the voltage dividing ratio can be adjusted according to the rotation speed of the electric motor, so that the rotation speed of the electric motor is reduced. Even if the back electromotive force generated in the armature winding is low, the dynamic range can be widened, so that the detection accuracy of the voltage detecting means can be improved and a highly reliable electric washing machine can be realized.

[0035]

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

(Embodiment 1) FIG. 1 is a circuit diagram of an inverter device provided in an electric washing machine in this embodiment. Reference numeral 1 denotes an AC power supply to which a rectifier circuit 2 is connected. The rectifier circuit 2 is configured by a series circuit including a diode bridge 2a and two smoothing electrolytic capacitors 2b and 2c, and supplies a DC power of twice the AC power 1 to the inverter circuit 3. Therefore, the effective voltage of the AC power supply 1 is 10
At 0 V, a DC power of about 280 V is output.

The inverter circuit 3 has a three-phase six-stone structure with three high-potential-side switching means 3a, 3b, 3c and three low-potential-side switching means 3d, 3e, 3f. Supply wave AC power.
Each of the switching means 3a to 3f is constituted by a parallel circuit of an IGBT and a reverse connection diode capable of supporting high-frequency switching and large current capacity. The switching means 3
a to 3f are not limited to this, and may be, for example, a parallel circuit of a triac and a reverse connection diode.

Although not particularly shown, the electric motor 4 comprises a rotor and a stator. The stator is an armature winding 4
a, 4b and 4c, and the armature windings 4a to 4c
Has a three-phase star connection configuration. The rotor has a configuration having a permanent magnet 4d. The specific configuration is shown in FIGS.

The voltage detecting means 5 detects the voltage of each terminal of the electric motor. In this embodiment, integrating circuits 5a, 5b, 5c and comparators 5d, provided for each terminal,
5e, 5c. Integrating circuits 5a, 5b, 5
c is composed of at least two resistors and capacitors, and the comparators 5d, 5e and 5f are integrated circuits 5a, 5b and 5f.
The composite voltage of two output voltages out of c is compared with the output voltage of the remaining one integration circuit, and a high or low is output according to the result.

However, the circuit configuration of the voltage detecting means 5 is not particularly limited to this. For example, the integration circuit 5
A DC cut capacitor may be connected to the outputs from a to 5c. Further, a method of detecting the voltage at the neutral point of the three-phase winding constituted by the armature windings 4a to 4c and comparing the voltage at the neutral point with the terminal voltage of the electric motor 4 may be used. As described above, the rotation of the rotor changes the magnetic flux linking the armature windings 4a to 4c, thereby generating a back electromotive force in the armature winding 4a. What is necessary is just to detect the back electromotive force and output a signal indicating the relative position of the permanent magnet 4b of the rotor with respect to the stator.

The control means 6 is constituted by a microcomputer or a plurality of logic circuits. The control means 6 sends on / off signals of the switching means 5a to 5f to the drive circuit 7 in accordance with a combination of three logic signals output from the voltage detection means 5. Output. In this embodiment, the combination of the output signal of the voltage detecting means 5 and the ON / OFF state of the switching means are stored in advance in a memory in the microcomputer as a table, and each time the output signal of the voltage detecting means 5 is switched, The on / off signals of the switching means 5a to 5f are output to the drive circuit 7.

In the electric washing machine of this embodiment, the electric motor 4
There are forward and reverse rotation directions, and in the voltage detecting means 5 of the present embodiment, the order of logic output for each rotation direction changes. Therefore, it is necessary to provide the table for each rotation direction. However, this table is an example, and the present invention is not limited to this. Further, the control means 6 sets the on / off state of the switching means 3a to 3f and sets the conduction ratio of the switching means 3a to 3f.
An on / off signal is output to the drive circuit 7 at kHz. In this embodiment, the microcomputer used is capable of performing 8-bit parallel processing, and has an internal ROM.
(Read only memory) has an inverter circuit 3
In addition to the above control, a washing / dehydrating sequence required to operate as the electric washing machine of the present embodiment is programmed.

In the present embodiment, the drive circuit 7 is constituted by a push-pull circuit including an NPN transistor and a PNP transistor. When the drive circuit 7 is on, it supplies 15 V power to the gate terminals of the IGBTs constituting the switching means 3a to 3f. When it is off, the voltage of the gate terminal is set to 0V. The configuration of the drive circuit 7 is not limited to this, but may be a dedicated IC or an electrically insulated IC.
Or the like may be used.

Although the present embodiment employs an intelligent power module in which the inverter circuit 3 and the drive circuit 7 are packaged in one module to reduce the mounting area, it is particularly limited to the intelligent power module. It does not matter if it has an inverter circuit 3 and a drive circuit 7 instead.

As described above, by providing the voltage detecting means 5, the relative positions of the permanent magnet 4b constituting the rotor of the electric motor 4 and the stator of the electric motor 4 can be detected. Alternatively, there is no need to provide a position detecting means constituted by a Hall element.

FIG. 2 is a block diagram of the electric washing machine according to the present embodiment. As shown in FIG. 2, the water receiving tub 11 is a washing and dewatering tub 13 in which a stirring blade 12 is rotatably provided on the inner bottom.
Is rotatably provided, and is suspended from a washing machine main body 15 by a suspension 14. The speed reduction mechanism 16 is provided in the water receiving tank 1.
The motor 4 is provided at the bottom of the motor 1 and transmits power to the stirring blade 12 and the washing and dewatering tub 13. The water supply valve 17 supplies water to the washing and dewatering tub 13, and the drainage valve 18 drains washing water and the like in the washing and dehydration tub 13. The control device 19 of the electric motor 4 is provided with an inverter device having the same configuration as that shown in FIG. 1. In addition to the inverter device, a drive circuit of the water supply valve 17 and the drain valve 18 and a user operate the same. And an operation display unit for the operation.

The speed reduction mechanism 16 has a planetary gear. When the stirring blade 12 is driven to rotate, the sun gear is driven by the output shaft of the electric motor 4 and the rotation of the planetary gear is transmitted to the stirring blade 12. , And reduces the output torque of the electric motor 4 to 6 times. In the case of rotating the washing and dewatering tub 13 such as dehydrating, the speed reduction mechanism 16 is separated from the output shaft of the electric motor 4 by a clutch mechanism (not shown), and the washing and dewatering tub 13 is directly driven by the electric motor 4.
However, the present invention is not particularly limited to such a configuration of the electric motor. For example, a configuration in which the power of the electric motor 4 is transmitted to the reduction mechanism 16 by a belt, or the power of the electric motor 4 is directly provided to the stirring blade 12 without providing the reduction mechanism 16. A direct drive configuration that communicates may be used.

FIG. 3 shows the mechanical structure of the electric motor 4. As shown in FIG. 3, the stator 21 is composed of a stator 21 and a rotor 22. The stator 21 has windings 21b, 2
1c, 21d, 21e, 21f, 21g, 21h, 21
i, 21j, 21k, 21l, and 21m are wound.

The rotor 22 includes a cup-shaped iron core 22a operating as a back yoke and permanent magnets 22b, 22c, 22d, 22e, 22f, and 22f adhered to the surface of the iron core 22a.
2g, 22h, 22i and an output shaft 22j. Here, as the permanent magnets 22b to 22i, parallel-oriented ferrite magnets are used. In addition, the permanent magnet 22
The magnets c, 22e, 22g, and 22j are magnetized so that the N poles come outward, and the permanent magnets 22b, 22d, and 22j
f and 22h are magnetized so that the south pole comes to the outside.

In this embodiment, the stator 21 is disposed outside and the rotor 22 is disposed inside. However, the present invention is not limited to such a configuration. May be provided outside the stator.

As described above, in the electric motor 4 of the present embodiment, the relative position detection of the permanent magnets 22b to 22i with respect to the stator 21 does not have to be performed by the position detecting means constituted by the Hall IC or the Hall element. As a result, there is no need to connect the position detecting means and the control device 19 by wiring, so that wiring costs and the like are eliminated, and the cost can be reduced. In addition, since the noise of the electric motor 4 does not adhere to the wiring, a reliable electric washing machine having high noise resistance can be realized. Also, there is no need to provide an installation location for the position detecting means, and the electric motor 4 can be made thin, so that the height of the electric washing machine can be reduced. In the present embodiment, the motor 4 has a configuration of 8 poles and 12 slots. However, the present invention is not particularly limited to this configuration, and other numbers of poles and slots may be used.

FIG. 4 shows the connection of the windings 21b to 21m. As shown in FIG. 4, by connecting four windings in series, the armature windings 4a, 4b, 4
c. The black circles on each winding indicate the polarity. When a current is applied from the side with the black circle on each winding, the winding is performed so that an N pole is generated on the inner (rotor side) surface of each tooth. The wire is wound.

As described above, by detecting the back electromotive force generated in the armature winding by using the voltage detecting means 5, it is not necessary to provide the motor 4 with a position detecting means constituted by a Hall IC or the like. In addition, wiring for connecting the control device 19 of the electric washing machine and the position detecting means is not required, so that cost reduction and improvement of noise resistance can be realized. In addition, the height of the electric motor 4 can be reduced by the height of the position detecting means, and the size or capacity of the electric washing machine can be reduced.

(Embodiment 2) FIG. 5 shows the characteristics of a motor having a permanent magnet in a rotor on dq coordinate axes. Eo is the back electromotive force generated in the armature winding, Φa is the magnetic flux of the permanent magnet, I is the current flowing in the armature winding, L is the mutual inductance between the permanent magnet and the armature winding, and Φo is Φ
The vector sum of a and LI, R is the resistance of the armature winding.
Va is a voltage applied between the terminals of the armature windings 4a to 4c. Eo and Ea can be expressed by the following equations using the electrical angular velocity ω.

Eo = ωΦo Ea = ωΦa As shown in FIG. 5, the phase of the back electromotive force Eo generated in the armature winding is such that as the current I flowing through the armature winding increases, the back electromotive force Ea generated by the magnetic flux of the permanent magnet increases. It can be seen that the phase is advanced with respect to the phase. In other words, the phase of the output signal of the voltage detecting means 5 that detects the back electromotive force Eo is advanced,
If the switching means is controlled to be turned on and off at the same timing, unstable operation such as a decrease in the torque of the electric motor 4 or an excessive current flowing through the armature windings will occur. In experiments by the authors, it has been confirmed that when the advance phase exceeds 30 degrees, the operation becomes particularly unstable and stops.

FIG. 5 also shows that the phase of the back electromotive force Eo becomes more advanced than the phase of the back electromotive force Ea generated from the magnetic flux Φa of the permanent magnet as the inductance L increases.

FIG. 6 shows a configuration of an inverter device provided in an electric washing machine according to a second embodiment of the present invention. The current detecting means 31 includes a current detecting resistor 31a, a first peak hold circuit 31b, an amplifier circuit 31c, and a second peak hold circuit 31d. The current detection resistor 31a detects the peak value of the input current of the inverter circuit 3.

In this embodiment, detecting the peak value of the input current of the inverter circuit 3 means detecting the peak value of the current flowing through all the armature windings 4a, 4b, 4c. Therefore, the armature windings 4a, 4a, 4c, and 4c can be surely formed with a simpler configuration than when currents flowing through the armature windings 4a, 4b, 4c are detected using three current transformers.
b, 4c can be detected.

The first peak hold circuit 31b peak-holds the voltage waveform of 16 kHz output from the current detection resistor 31a and outputs it to the amplifier circuit 31c. The voltage waveform at this time is a waveform close to the envelope of the voltage waveform output from the current detection resistor 31a. The amplifier circuit 31c is an operational amplifier O
By using P1, the first peak hold circuit 31
b is inverted and amplified, and the second peak hold circuit 31
Output to d.

The second peak hold circuit 31d holds the peak value of the amplifier circuit 31c and outputs it to the control means 33 as a DC voltage. The output voltage Vin of the current detecting means 31 is substantially proportional to the magnitude of the current flowing through the current detecting resistor 31a. That is, the output voltage Vin increases as the current increases.

The configuration of the current detecting means 31 is not limited to this, and a high-speed operational amplifier may be used without using the first peak hold circuit 31b, or the current detecting resistor 31a may be directly used. Output may be detected.

The speed detecting means 32 detects the period Tin of the output signal of the comparator 5a constituting the voltage detecting means 5 by measuring it with a counter in the microcomputer. The frequency of the output signal of the comparator 5a is the same as the frequency of the back electromotive force generated in the armature windings 4a to 4c. That is, the frequency is proportional to the rotation speed of the electric motor 4.

The control means 33 comprises a microcomputer and a plurality of logic circuits. The microcomputer also detects the speed of the electric motor 4 as described above. Further, the output voltage of the current detecting means 31 is detected by the AD input terminal of the microcomputer. The microcomputer has a current detecting means 3 in advance.
The delay phase θd corresponding to the output voltage Vin of 1 is set on the memory as a data table. (This data table is referred to as a Vin-θd table.) When the control means 33 detects the output voltage Vin of the current detection means 31 and sets the delay phase θd, the control means 33 detects the voltage detected by the speed detection means 32. The delay time Td is set using the period Tin of the output signal of the means 5. Td, Ti
The relational expression of n and θd is as follows.

Td = Tin * θd / 360 The on / off signals of the switching means 3a to 3f are driven by the delay time Td after the logic of the output signal of the voltage detection means 5 is switched using the timer in the microcomputer of the control means 33. Output to the circuit 7.

FIG. 7 shows a Vin-θd table set in the microcomputer. As shown in FIG. 7, θd is divided into five levels. As a result, the microcomputer detects the current detecting means 3
Since the delay phase θd can be easily determined simply by determining which rank of the output voltage Vin of 1 is in the Vin-θd table shown in FIG. 7, the control time can be reduced. Further, the control unit 33 turns off all the switching units 3a to 3f when Vin is input such that the level of θd exceeds the maximum level.

Although the data table shown in FIG. 7 is provided in this embodiment, the present invention is not limited to this. For example, the relational expression between the output voltage Vin and the delay phase θd is stored in the microcomputer. Alternatively, θd may be set based on this formula every time the logic of the output signal of the voltage detection means 5 switches.

As described above, the current flowing in the armature winding is detected by the current detecting means 31, and the on / off timing of the switching means 3a to 3f is delayed in accordance with the detected current value, so that the armature windings 4a to 4c Can be made almost 90 degrees to the magnetic flux of the permanent magnet 4d, so that the output torque of the electric motor 4 can be made sufficient.

Next, the operation of the electric washing machine shown in FIG. 2 in this embodiment will be described. When the operation is started in a state where the user puts the laundry and the detergent into the washing and dewatering tub 13, the water supply valve 17 is opened, the tap water is poured into the water receiving tub 11, and the water in the water receiving tub 11 is drained. Raise to the specified water level.

In the present embodiment, the washing and dewatering tub 13 is directly connected to the output shaft of the electric motor 4 by the clutch mechanism, and the rotation of the washing and dewatering tub 13 is performed at about 150 rpm. By rotating the washing and dewatering tub 13 at 150 rpm, the laundry is stuck to the inside of the washing and dewatering tub 13 by centrifugal force, and the water in the water receiving tub 11 decreases when the water level at the center decreases. At the same time, a water flow is generated in a circulation path in which the water level outside the washing and dewatering tub 13 rises and falls again from the upper part of the water receiving tub 11 into the washing and dewatering tub 13.

With this water flow, the washing liquid is passed through the laundry to wash the laundry. In the present invention, this cleaning method is referred to as pass-through cleaning. Here, since the washing liquid passing through the laundry has a strong force particularly directed to the outside of the washing and dewatering tub 13 due to centrifugal force, the effect of the passing washing is very large. 13 increases as the rotation speed increases, and increases as the number of holes around the washing and dewatering tub 13 increases.

In the case of performing the pass-through washing, the washing and dewatering tub 13 is rotated while the washing liquid and the laundry containing the washing liquid are placed in the washing and dewatering tub 13.
Although a high torque of about m is required, a brushless DC motor having a permanent magnet in the rotor is adopted as the electric motor 4 and a high torque output at a low speed is ensured, so that the passage cleaning can be realized. .

In the present embodiment, after the passage cleaning, the cleaning by the stirring blade 12 is performed. In this cleaning, the washing and dewatering tub 13 is disconnected from the output shaft of the electric motor 4 by the clutch mechanism, and the speed reduction mechanism 16 is connected to the output shaft of the electric motor 4 to reduce the rotation speed of the electric motor 4 to 1/6 and agitate. The wing 12 is rotationally driven. At this time, the control device 19 controls the electric motor 4 to repeat forward rotation and reverse rotation. Washing by the stirring blades 12 often involves laundry, and the torque applied to the electric motor 4 tends to vary from 1 to 5 Nm.

When the washing with the stirring blade 12 is completed, the drain valve 18 is opened, and the washing liquid in the water receiving tank 11 is drained. Thereafter, the output shaft of the electric motor 4 is directly connected to the washing and dewatering tub 13 by the clutch mechanism in the same manner as in the pass washing, and the washing and dehydrating tub 13 is rotationally driven by the electric motor 4 at a higher rotational speed than in the pass washing. Then, the washing liquid contained in the laundry is centrifugally dehydrated.

Next, rinsing is performed. Here, the stirring blade 12 is driven to rotate by the electric motor 4 via the speed reduction mechanism 16 by the same operation as the cleaning by the stirring blade 12.

In the last dehydration step, the drain valve 18 is opened to drain the cleaning liquid in the water receiving tub 11, and the washing and dehydrating tub 13 and the electric motor 4 are directly connected by the clutch mechanism in the same manner as in the case of the pass-through cleaning. The dewatering tub 13 is driven by the electric motor 4 for 900 r.
The washing and dewatering tub 13 is rotated by centrifugal force and the laundry is dehydrated by centrifugal force. At this time, a torque of about 1 Nm is required.

As described above, in the electric washing machine, the required torque of the electric motor 4 differs depending on the washing and dehydrating process. This torque also varies depending on the amount of laundry. Therefore, by providing the inverter device shown in FIG. 6, even if the torque fluctuates and the current flowing through the armature winding changes, the permanent magnet 4d in the dq coordinates shown in FIG.
By controlling the switching means 3a to 3f so that a current flows through the armature winding so as to be substantially orthogonal to the magnetic flux of the electric motor 4, the electric motor 4 can be reliably driven and the washing and dehydration can be performed. Machine can be realized.

(Embodiment 3) The memory in the microcomputer of the control means 33 shown in FIG. 6 stores the delay phase θd corresponding to the cycle Tin of the output signal of the voltage detection means 5 detected by the speed detection means 32 in advance. A data table has been set. (This table will be referred to as a Tin-θd table.) The control means 33 thereby controls the switching means 3a to 3f in accordance with the output of the speed detection means 32.
Is delayed by a predetermined phase θd from the point in time when the output signal of the voltage detecting means 5 switches. Others are the same as the second embodiment.

Although a table is provided in the present embodiment, the present invention is not limited to this. For example, a relational expression between the output Tin of the speed detecting means and the delay phase θd is provided in the microcomputer, and the voltage detection is performed. Each time the logic of the output signal of the means 5 switches, θd may be set based on this equation. When the delay phase θd is determined as in the second embodiment, the control means 33 calculates a delay time Td of the on / off timing of the switching means 3a to 3f, and outputs an on / off signal of the switching means 3a to 3f to the drive circuit 7 based on this. I do.

FIG. 8 is a graph showing an example of the relationship between Tin and the leading phase θ with respect to the phase of the magnetic flux of the permanent magnet 4d of the output signal of the voltage detecting means 31. The voltage detecting means 5 shown in FIG. 6 connects low-pass filters 5a to 5c to terminals of the electric motor 4. The low-pass filters 5a to 5c have a terminal voltage waveform of 9 at the rotation speed of the motor 4 of 900 rpm.
Although the phase is set so as to be a 0-degree lag phase, when the rotation speed of the electric motor 4 changes, the lag phase becomes smaller due to the frequency characteristics of the low-pass filters 5a to 5c.

That is, the switching timing of the output signal of the voltage detecting means 5 is advanced as the rotation speed of the electric motor 4 decreases. However, by compensating for this advance phase using a Tin-θd table provided in the microcomputer of the control means 33, the output signal of the voltage detection means 5 determines the on / off timing of the switching means 3a to 3f according to the speed of the motor 4. The phase is delayed by a predetermined phase θd from the time when the switching is performed. Therefore, the switching means 3a to 3f are controlled so that a current flows through the armature winding so as to be substantially orthogonal to the magnetic flux of the permanent magnet 4d in the dq coordinates shown in FIG. And the operating conditions of the washing and dewatering process required for the electric washing machine described in the second embodiment can be realized.

(Embodiment 4) The memory in the microcomputer of the control means 33 shown in FIG. 6 stores the output voltage Vin of the current detection means 31 and the delay phase θd corresponding to the detection cycle Tin of the speed detection means 32 in advance. A data table is provided. Other configurations are the same as in the second embodiment.

FIG. 9 shows a data table of θd set in the microcomputer in this embodiment. As shown in FIG. 9, θd is classified into five ranks. Each set value θd1, θd2, θd3, θd4,
The magnitude relationship of θd5 is as follows.

Θd1 <θd2 <θd3 <θd4 <θd5 As described above, in this embodiment, the microcomputer is provided with the data detecting means 31 by providing the data table.
Output voltage Vin, the detection period Tin of the speed detection means 32
Θd can be easily set simply by detecting.
Accordingly, the calculation processing time can be reduced, and high-speed control can be performed. However, the present invention is not limited to this. If the microcomputer is a high-speed microcomputer, V
A relational expression between in, Tin and θd is provided, and Vin and T
When in is determined, θd may be derived by calculation.

As described above, the switching means 3a to 3f are delayed by a predetermined phase θd from the switching point of the output signal of the voltage detecting means 5 in accordance with the current flowing through the armature windings 4a to 4c and the rotation speed of the motor 4. By performing the on / off control, the phase advance of the output signal of the voltage detection means 5 due to the current flowing through the armature windings 4a to 4c and the rotation speed of the electric motor 4 described in the second and third embodiments can be corrected. Since the switching means 3a to 3f are controlled so that a current flows through the armature winding so as to be substantially orthogonal to the magnetic flux of the permanent magnet 4d in the dq coordinates shown in FIG. 5, the operation of the electric motor 4 is possible. The region can be widened, and as a result, the operating conditions of the washing and dewatering process required for the electric washing machine described in the second embodiment can be realized.

(Embodiment 5) FIG. 10 shows operation waveforms of each part of the inverter device shown in FIG. (A) shows the output waveform of the comparator 5a, (b) shows the output waveform of the comparator 5b, and (c) shows the output waveform of the comparator 5c. (D) is an on / off waveform of the switching means 3a,
(E) is the ON / OFF waveform of the switching means 3b, (f)
Is an on / off waveform of the switching means 3c, (g) is an on / off waveform of the switching means 3d, (h) is an on / off waveform of the switching means 3e, and (i) is an on / off waveform of the switching means 3f. (J) shows the voltage waveform at the U terminal, (k) shows the voltage waveform at the W terminal, and (l) shows the voltage waveform at the V terminal.

As shown in FIG. 8, the control means 33 performs on / off control so as to attain a predetermined conduction ratio at about 16 kHz during the first half of the ON period of the IGBTs constituting the switching means 3a to 3f. It is what you are doing. Others are the same as the fourth embodiment.

Td in FIG. 8 is a delay time of the switching timing of the switching means 3a to 3f set by the microcomputer provided in the control means 31 based on the output values of the current detection means 31 and the speed detection means 32. Further, t1 in FIG. 8 is the energizing period of the reverse connection diode constituting the switching means 3c, and t2 is the switching means 3f.
Shows the energization period of the reverse connection diode that constitutes.

As shown in FIG. 8, the switching means 3a
Are controlled on and off so as to have a predetermined conduction ratio at about 16 kHz in the first half of the on period. As a result, the voltage applied to the armature winding having the open terminal becomes smaller and becomes substantially constant regardless of which of the switching means 3a to 3f is turned off. Is also substantially constant as di / dt decreases. As a result, the conduction period t of the reverse connection diode
1, t2 becomes almost constant and becomes longer. As a result, the influence on the low-pass filter of the voltage detecting means 5 due to the conduction period of the reverse connection diode becomes constant, so that the stability of the output of the voltage detecting means 5 can be ensured.

Further, as described above, the switching means 3
The period of the first half of the ON period from a to 3f is 16 kHz.
By performing on / off control in step (1), di / dt of the fall of the regenerative current flowing through the armature winding can be reduced, and electromagnetic noise caused by the large di / dt can be reduced. An electric washing machine can be realized.

(Embodiment 6) FIG. 11 shows operation waveforms of the inverter device shown in FIG. (A) shows the output waveform of the comparator 5d, (b) shows the output waveform of the comparator 5e, and (c) shows the output waveform of the comparator 5f. (D) is an on / off waveform of the switching means 3a,
(E) is the ON / OFF waveform of the switching means 3b, (f)
Is an on / off waveform of the switching means 3c, (g) is an on / off waveform of the switching means 3d, (h) is an on / off waveform of the switching means 3e, and (i) is an on / off waveform of the switching means 3f. (J) shows the voltage waveform at the U terminal, (k) shows the voltage waveform at the W terminal, and (l) shows the voltage waveform at the V terminal.

As shown in FIG. 9, the control means 33 performs on / off control so as to have a predetermined conduction ratio at about 16 kHz in the latter half of the on-period of each of the switching means 3a to 3f. . Others are the same as the fourth embodiment.

Td in FIG. 9 is a delay time of the switching timing of the switching means 3a to 3f set by the microcomputer provided in the control means 31 based on the output values of the current detection means 31 and the speed detection means 32. Further, t1 in FIG. 9 is the energizing period of the reverse connection diode constituting the switching means 3c, and t2 is the switching means 3f
Shows the energization period of the reverse connection diode that constitutes.

As shown in FIG. 9, the switching means 3a
Are controlled on and off so as to have a predetermined conduction ratio at about 16 kHz in the second half of the on period. As a result, the voltage applied to the armature winding having the open terminal increases and becomes substantially constant regardless of which of the switching means 3a to 3f is turned off. Di / dt also increases and becomes substantially constant. As a result, the conduction period t of the reverse connection diode
1, t2 becomes shorter and almost constant. As a result, the effect on the low-pass filter of the voltage detecting means 5 due to the energizing period of the reverse connection diode becomes constant and the energizing period of the reverse connecting diode becomes short, so that the influence on the voltage detecting means 5 becomes small, so that the output characteristics are stabilized. Voltage detecting means can be realized.

(Embodiment 7) FIG. 12 shows the configuration of the voltage detecting means. As shown in FIG. 10, the voltage dividing circuit 51 includes a series circuit of a resistor R1 and a resistor R2, a capacitor C1 connected in parallel to the resistor R2, a resistor R51a and a transistor tr1.
And a series circuit of a resistor R51b and a transistor tr2. Transistors tr1 and tr
Although not shown in FIG. 10, 2 is connected to the output terminal of the control means and is controlled on / off by the control means.

In this embodiment, it is assumed that the base terminal of tr1 is connected to the terminal a of the control means. It is also assumed that the base terminal of tr2 is connected to the terminal b of the control means. The voltage dividing circuits 52 and 53 have the same configuration. The base terminals of tr3 and tr5 are connected to terminal a of the control means. The base terminals of tr4 and tr6 are connected to the terminal b of the control means. In addition,
The configuration other than the voltage detection means is the same as that of the fourth embodiment. The voltage dividing circuits 51, 52, and 53 function to divide the terminal voltage of the electric motor 4 and also function as an integrating circuit.

The operation of the electric washing machine provided with the inverter device having the voltage detecting means shown in FIG. 10 will be described. As described in the second embodiment, the operating conditions of the electric washing machine of the present invention are roughly divided into three. The first operating condition is a passing washing process in which the washing and dewatering tub 13 is rotated at about 150 rpm, and water is passed through the laundry using the centrifugal force generated at that time to wash. The second operation condition is a spin-drying step in which the washing and spin-drying tub 13 is driven to rotate at about 900 rpm, and spin-drying of the laundry is performed using centrifugal force generated at that time. The third operation condition is a stirring and washing process in which the stirring blade 12 is rotationally driven via the speed reduction mechanism 16. In the stirring and washing process, the rotation speed of the electric motor 4 is 720 rpm.

In the pass washing step, the control means is a terminal,
The terminals b are both kept off. Thereby, the voltage dividing circuit 5
The output voltage of No. 1 is divided by the resistors R1 and R2.

In the stirring and washing process, the control means keeps the terminal a on and the terminal b off. Thus, the voltage output from the voltage dividing circuit 51 is divided by the combined resistance of the resistor R2 and the resistor R51a and the resistor R1.

In the dehydration step, the control means keeps both the terminal a and the terminal b on. As a result, the output voltage of the voltage divider 51 is divided by the resistor R1 and the combined resistor of the resistor R2, the resistor R51a, and the resistor R51b.

As described above, by changing the magnitudes of the resistance values of the voltage dividing circuits 51, 52 and 53 for each of the steps where the rotation speed of the electric motor 4 is different, the voltage dividing ratio of the series circuit by the resistance is changed. Even when the rotation speed of the motor 4 is low, the back electromotive force generated in the armature winding can be reliably detected. Therefore, 5 to 6 like the electric washing machine of the present embodiment.
Even if the motor has an operating condition having a difference in rotation speed twice, the back electromotive force can be reliably detected and the motor can be driven to rotate. Particularly, even when the rotation speed of the electric motor is low, the back electromotive force can be detected accurately, so that the electric motor can be driven to rotate accurately and the washing performance of the electric washing machine can be improved.

[0101]

As described above, according to the first aspect of the present invention, the electric washing machine of the present invention has a motor having a permanent magnet on a rotor and an armature winding on a stator. A control means for controlling on / off of an inverter circuit connected to the motor and a switching means constituting the inverter circuit, and a voltage for detecting a back electromotive force generated in an armature winding of the motor during rotation driving of the rotor. Detecting means for detecting the back electromotive force generated in the armature winding, the control means including an inverter device for controlling on / off of the switching means by an output of the voltage detecting means in accordance with a rotation direction of the electric motor; The motor can be detected by the terminal voltage of the motor, so that the relative position between the rotor and the stator of the motor can be increased without providing the motor with a position detecting means constituted by a Hall IC. Position can be detected, the wiring between the position detecting means and the control means can be eliminated, and the height of the electric motor can be reduced, so that the electric washing machine can be made compact at low cost. .

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a current detecting means for detecting a current corresponding to a current flowing through an armature winding of the electric motor, The control means delays the on / off timing of the switching means by a predetermined phase according to the outputs of the current detection means and the voltage detection means,
Thereby, even if the phase of the back electromotive force waveform generated in the armature winding due to the current flowing in the armature winding is advanced from the position of the permanent magnet of the rotor,
The current position of the permanent magnet of the rotor is estimated, and the switching means can be turned on and off substantially in synchronization with the position of the permanent magnet of the rotor.

Thus, the switching timing can be adjusted so that the ratio of the output torque per current of the electric motor is maximized, so that the operable region of the electric motor can be expanded, and various washing methods can be performed by the electric washing machine. Can be realized. Moreover, the electric washing machine can be made highly efficient.

According to a third aspect of the present invention, in the first aspect of the present invention, there is provided a speed detecting means for detecting a speed of the electric motor based on an output of the voltage detecting means, wherein the control means is provided. The on-off timing of the switching means is changed by a predetermined phase according to the outputs of the speed detecting means and the voltage detecting means. In a motor having a permanent magnet in the rotor, if the current flowing in the armature winding is constant, the phase of the back electromotive force generated in the armature winding due to the rotation speed of the motor and the rotation of the rotor It has the characteristic that the phase of the permanent magnet fluctuates. Basically, when compared with the phase of the permanent magnet,
As the rotational speed of the electric motor is lower, the phase is advanced.

Generally, the magnitude and frequency of the back electromotive force generated in the armature winding are proportional to the rotation speed of the motor, and the lower the speed, the lower the back electromotive force and the lower the frequency. Therefore, if the voltage detection means has a configuration having a low-pass filter or a high-pass filter,
Due to the frequency characteristic, the phase of the output signal of the voltage detecting means is not synchronized with the position of the permanent magnet of the rotor due to the rotation speed of the motor.

If the voltage detecting means compares the back electromotive force generated in the armature winding with a predetermined reference voltage, the magnitude of the back electromotive force generated in the armature winding depends on the magnitude of the back electromotive force generated in the armature winding. The phase to be detected fluctuates. Accordingly, the rotation speed of the electric motor is detected by the speed detection unit, and the control unit changes the on / off timing of the switching unit by a predetermined phase according to the detection speed of the speed detection unit. Can be rotationally driven. Thereby, the electric motor can be reliably driven to rotate even in the electric washing machine having a plurality of rotation speed conditions,
The washing and dewatering performance can be satisfied.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a speed detecting means for detecting a speed of the electric motor based on an output of the voltage detecting means, and an armature of the electric motor. A current detecting means for detecting a current corresponding to a current flowing through the winding; and the control means determines an on / off timing of the switching means in accordance with outputs of the speed detecting means, the current detecting means, and the voltage detecting means. Even if the phase of the back electromotive force generated in the armature winding changes due to a change in the rotation speed of the electric motor or a current flowing in the armature winding, the rotor may be changed in phase. Since the switching means can be turned on and off substantially in synchronization with the phase of the permanent magnet, the operable region of the electric motor can be expanded.

As a result, even in an electric washing machine having a plurality of washing conditions, the electric motor can be reliably driven to rotate, and the washing and dewatering performance can be satisfied. Further, since the operable region of the electric motor can be expanded even when the amount of laundry increases, an electric washing machine which can sufficiently cope with the problem can be realized.

According to the invention described in claim 5, in the invention described in any one of claims 1 to 4, the control means sets the conduction ratio in a first half of a switching period of the switching means. The regenerative current period generated when the switching means is turned off can be kept constant regardless of whether the switching means is on the high potential side or the low potential side, and the voltage detecting means Can detect the back electromotive force generated in the armature winding without being affected by the switching means, and can easily control the on / off timing of the switching means by the control means. And a low-cost inverter device can be realized.

Further, since the period of the regenerative current is lengthened, the change in the current flowing through the armature winding can be reduced, and the motor can be rotationally driven with low noise. Therefore, a low noise or low cost or compact electric washing machine can be realized.

According to the invention of claim 6, in the invention of any one of claims 1 to 4,
The control unit controls the conduction ratio in the latter half of the switching period of the switching unit, and the switching unit sets a regenerative current period generated when the switching unit is turned off in the same manner as in the fifth embodiment. It can be constant on both the high potential side and the low potential side.
Further, since the regenerative current period is shortened, the period for detecting the back electromotive force generated in the armature winding can be lengthened, and the voltage detecting means can reliably detect the back electromotive force. it can. Therefore, the control means can easily control the on / off timing of the switching means, and a low-cost and highly reliable electric washing machine can be realized.

According to the invention of claim 7, in the invention of any one of claims 1 to 6,
The voltage detecting means has a voltage dividing circuit for dividing a terminal voltage of an armature winding constituting the electric motor, and the voltage dividing circuit is configured to switch a voltage dividing ratio according to an output of the speed detecting means. Since the voltage division ratio can be adjusted in accordance with the rotation speed of the motor, the dynamic range can be increased even if the number of rotations of the motor is low and the back electromotive force generated in the armature winding is small. The detection accuracy of the means can be improved, and a highly reliable electric washing machine can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of an inverter device included in an electric washing machine according to a first embodiment of the present invention.

FIG. 2 is a system configuration diagram of the electric washing machine.

FIG. 3 is a top view of a main part of a motor provided in the electric washing machine.

FIG. 4 is a connection diagram of armature windings of the electric motor of the electric washing machine.

FIG. 5 is a vector diagram at dq coordinates of the electric motor of the electric washing machine.

FIG. 6 is a block diagram showing an example of an inverter device provided in the electric washing machine according to the second to seventh embodiments of the present invention.

FIG. 7 is a diagram showing a data table provided in control means of the electric washing machine according to the second embodiment of the present invention.

FIG. 8 is a diagram showing a frequency characteristic of the voltage detecting means according to the third embodiment of the present invention.

FIG. 9 is a diagram showing a data table provided in the control means of the electric washing machine according to the fourth embodiment of the present invention.

FIG. 10 is a diagram showing operation waveforms of main parts of an inverter device provided in the electric washing machine according to a fifth embodiment of the present invention.

FIG. 11 is a diagram showing operation waveforms of main parts of an inverter device provided in an electric washing machine according to a sixth embodiment of the present invention.

FIG. 12 is a block circuit diagram of voltage detecting means provided in an electric washing machine according to a seventh embodiment of the present invention.

FIG. 13 is a block diagram of an inverter device provided in a conventional electric washing machine.

FIG. 14 is a system configuration diagram of the electric washing machine.

[Explanation of symbols]

 Reference Signs List 3 inverter circuit 3a to 3f switching means 4 motor 4a to 4c armature winding 4d permanent magnet 5 control means 31 current detection means 32 speed detection means

 ──────────────────────────────────────────────────の Continued on the front page (72) Tomoya Toto, Inventor 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yasumichi Kobayashi 1006 Kadoma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. F term (for reference) 3B155 AA06 AA10 BA03 BA23 BB05 BB19 CA16 CB06 GC06 HB10 HC06 HC07 KA33 KB08 LA04 LB18 LC02 LC15 LC28 MA01 MA02 MA05 MA07 MA09 5H560 AA10 BB04 BB07 BB15 DA13 EB01 EC02 TT0711 GG03RR

Claims (7)

[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 on / off of a switching means constituting the inverter circuit. A voltage detecting means for detecting a back electromotive force generated in an armature winding of the motor during rotation driving of the rotor, wherein the control means outputs an output of the voltage detecting means according to a rotation direction of the motor. An electric washing machine provided with an inverter device for turning on and off the switching means. 2. An electric motor further comprising a current detecting means for detecting a current flowing through an armature winding of the motor, wherein the control means sets an on / off timing of the switching means to a predetermined phase in accordance with outputs of the current detecting means and the voltage detecting means. The electric washing machine according to claim 1, wherein the electric washing machine is changed. 3. A speed detecting means for detecting a speed of the electric motor based on an output of the voltage detecting means, wherein the control means determines an on / off timing of the switching means in accordance with the outputs of the speed detecting means and the voltage detecting means. The electric washing machine according to claim 1, wherein the phase is changed. 4. A motor comprising: a speed detecting means for detecting a speed of the motor based on an output of the voltage detecting means; and a current detecting means for detecting a current corresponding to a current flowing through an armature winding of the motor.
2. The electric washing machine according to claim 1, wherein the control unit changes the on / off timing of the switching unit by a predetermined phase according to the outputs of the speed detection unit, the current detection unit, and the voltage detection unit. 3. 5. The electric washing machine according to claim 1, wherein the control unit controls the duty ratio in a first half of a switching period of the switching unit. 6. The electric washing machine according to claim 1, wherein the control means controls the duty ratio in a latter half of a switching period of the switching means. 7. The voltage detecting means has a voltage dividing circuit for dividing a terminal voltage of an armature winding constituting the motor, and the voltage dividing circuit switches a voltage dividing ratio according to an output of the speed detecting means. The electric washing machine according to any one of claims 3 to 6.