JP2000024365A - Electric washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent conduction noises or radiation noises of an operation display circuit from interfering with another electric apparatus or prevent malfunctions of the operation display circuit due to external noises by electrically insulating it and to preclude the possibility of an electric shock even if the operation display circuit is broken and a user touches the broken circuit. SOLUTION: Capacitors 3, 4 are connected to the output of a rectifier 2 for rectifying an alternating current power source 1 to control an inverter circuit 5 connected to the output of the rectifier 2 by means of a control circuit 6, whereby an electric power is supplied to the circuit 6 and an operation display circuit 7 through a power source circuit 8. The circuit 8 includes a transformer 13 having a plurality of secondary windings 20, 21, and an electric power is supplied to the control circuit 6 and the operation display circuit 7 from the windings 20, 21, respectively, and the circuit 7 is electrically insulated.

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 having an inverter circuit connected to an output of a rectifier for rectifying an AC power.

[0002]

2. Description of the Related Art Conventionally, an electric washing machine is disclosed in Japanese Patent Laid-Open No. 8-228.
No. 497 discloses an electric washing machine in which an electronic rectification circuit composed of three-phase six stones, that is, an inverter circuit, is connected to a stator of a motor having three-phase windings, and an output voltage of the inverter is connected. Connect the voltage digitizing circuit from
The output is input to a rectification control signal generator, and a pulse width modulation control means and a motor control microcomputer are provided, and a console microcomputer, that is, a washing condition selected by a user through an operation display circuit is instructed to the motor control microcomputer. A device for controlling an electronic motor is shown.

[0003]

However, in the above-mentioned conventional configuration, there is no description about the power supply for operating the components such as the inverter circuit, the motor control microcomputer, and the operation display circuit. For example, it is considered that power is supplied to each component from the same power supply circuit that outputs a DC voltage.

The inverter circuit is a high frequency PWM.
(Pulse width modulation), it is a source of noise. When the operation display circuit is operated by the same power supply, the noise from the inverter circuit is connected to the operation display circuit. To the AC power supply line, radiating noise from the operation display circuit or wiring, and transmitting conduction noise to the AC power supply, possibly damaging other electrical equipment.Conversely, for example, impulse noise or lightning There is a problem that a malfunction such as an inverter circuit is likely to occur due to an external noise such as a surge.

Here, the operation display circuit is a part where a user operates a button or the like. Therefore, if the operation part is damaged, the operation display circuit is switched to the same power supply as the inverter circuit connected to the AC power supply. There is a problem that the operation display circuit to be connected becomes a charging unit, and there is a fear of electric shock.

The power supply circuit receives power from an AC power supply and supplies power to the control circuit. However, the power supply circuit has a complicated structure and a structure for detecting the input current of the inverter circuit. Had the problem of becoming

The present invention solves the above-mentioned conventional problems. The operation display circuit is configured to be electrically insulated so that other electrical equipment may be damaged by radiation noise or conduction noise, or conversely, external noise may be caused. It is a first object of the present invention to prevent erroneous operation due to the electric shock, and to prevent the possibility of electric shock even when the operation display portion is destroyed and touched by a user.

It is a second object of the present invention to realize a power supply circuit with a relatively simple configuration and to detect an input current of an inverter circuit with a relatively simple configuration by using a current detection resistor.

[0009]

According to the present invention, a capacitor is connected to an output of a rectifier for rectifying an AC power supply, and an inverter circuit connected to the output of the rectifier is controlled by a control circuit. Then, power is supplied from the power supply circuit to the control circuit and the operation display circuit. The power supply circuit has a transformer having a plurality of secondary windings, and supplies power to the control circuit and the operation display circuit from separate secondary windings, and the operation display circuit is electrically insulated. .

Thus, the operation display circuit can be configured to be electrically insulated to prevent other electrical equipment from being damaged by radiated noise or conducted noise, or to prevent malfunction due to external noise. Even when the operation display portion is destroyed and touched by the user, there is no fear of electric shock.

In order to achieve the second object, a capacitor is connected to the output of the rectifier for rectifying the AC power, and an inverter circuit connected to the output of the rectifier is controlled by a control circuit. Supply power. A negative input terminal of the inverter circuit, a negative terminal of the control circuit, and a first terminal of the power supply circuit are connected as a common terminal, and a current detection resistor is connected between the common terminal and the negative terminal of the capacitor. , A switching power supply that receives a voltage between a second terminal and the first terminal as an input, a second terminal of the power supply circuit is connected to another terminal of the capacitor, and a control circuit is connected to the second terminal of the power supply circuit. It is configured to operate by being supplied with a DC voltage output between a first terminal and the third terminal.

Thus, the power supply circuit can be realized with a relatively simple configuration, and the input current of the inverter circuit can be detected with a relatively simple configuration using the current detection resistor.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 of the present invention provides an AC power supply, a rectifier for rectifying the AC power, a capacitor connected to an output of the rectifier, and an inverter connected to an output of the rectifier. A control circuit for controlling the inverter circuit, an operation display circuit, and a power supply circuit for supplying power to the control circuit and the operation display circuit, wherein the power supply circuit has a plurality of secondary windings. And a separate 2 for the control circuit and the operation display circuit.
Power is supplied from the next winding, the operation display circuit is electrically insulated, the operation display circuit is electrically insulated from the AC power supply, radiation noise to other electric devices,
In addition to suppressing the emission of conducted noise, preventing malfunction of the device due to extraneous noise, and making the operation display circuit a non-charging part, if the operation display circuit is damaged, the user touched it As a result, electric shock can be prevented.

According to a second aspect of the present invention, there is provided an AC power supply, a rectifier for rectifying the AC power, a capacitor connected to an output of the rectifier, an inverter circuit connected to an output of the rectifier, and an inverter circuit. A control circuit for controlling, and a power supply circuit for supplying power to the control circuit,
A negative input terminal of the inverter circuit, a negative terminal of the control circuit, and a first terminal of the power supply circuit are connected as common terminals, and a current detection resistor is connected between the common terminal and the negative terminal of the capacitor. And
The power supply circuit is a switching power supply that receives a voltage between a second terminal and the first terminal as an input, and the second terminal of the power supply circuit is connected to another terminal of the capacitor, The circuit is configured to operate by being supplied with a DC voltage output between the first terminal and the third terminal of the power supply circuit, and to connect the first terminal of the power supply circuit to input and output. A relatively simple configuration with a common terminal can be used, and the input current of the inverter can be detected by the current detection resistor, so that the configuration can be realized with a relatively simple configuration.

According to a third aspect of the present invention, in the second aspect of the present invention, the power supply circuit has a decoupling capacitor between the first terminal and the second terminal. The resistance makes it possible to realize an electric washing machine that can also detect the input current of the inverter, and in addition, stabilizes the voltage input to the power supply circuit, and high-frequency ripple current flowing from the decoupling capacitor to the power supply circuit. Is supplied, the high-frequency ripple current flowing through the current detection resistor is reduced, and highly accurate current detection becomes possible.

[0016]

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

(Embodiment 1) As shown in FIG. 1, an AC power supply 1 is a commercial power supply of 100 V and 60 Hz, and the AC power supply 1 is rectified by a rectifier 2. The output of the rectifier 2 was connected to electrolytic capacitors 3 and 4 having a capacitance of 560 μF and a withstand voltage of 250 V, and the output of the rectifier 2 was configured using a transfer-molded intelligent power module of DIP type. The inverter circuit 5 is connected.

The control circuit 6 controls the inverter circuit 5, and supplies power to the control circuit 6 and the operation display circuit 7 from a power supply circuit 8. The output of the inverter circuit 5 is connected to a motor 12 constituted by a DC brushless motor having three-phase armature windings 9, 10, and 11.

Here, as described later, the power supply circuit 8
Transformer 13 having two secondary windings, rectifying diodes 14, 15, 16, electrolytic capacitors 17, 18, 1,
The control circuit 6 and the operation display circuit 7 are supplied with power from separate secondary windings 20 and 21, and the operation display circuit 7 is electrically insulated.

The operation display circuit 7 has, for example, a light emitting diode and a 7-segment display or a liquid crystal display for display, and a momentary switch provided below the membrane resin for operation. It sets the time, time, etc., and displays the operating status, the remaining time, and the like.

The communication circuit 22 performs communication between the control circuit 6 and the operation display circuit 7 by using, for example, a photocoupler.
It is configured to transmit and receive digital signals of a book. In addition, besides the photocoupler, for example, a device using a pulse transformer may be used, and a device for transmitting data using an optical fiber may also secure electrical insulation as in the present embodiment. In addition, data is exchanged.

Bootstrap circuits 23, 24, 25
Supplies drive power for the high-potential-side switching element in the inverter circuit 5, and during the period in which the low-potential-side switching element in the inverter circuit 5 is in the ON state,
By supplying the current from the capacitor 18, VUFB-VU
A DC voltage of about 15 V is supplied between the FSs, and this is applied between the gate and the emitter of the IGBT, which is a high-potential side switching element, and can be turned on. The same applies to the V phase and the W phase.

With the above configuration, in this embodiment, the output voltage of the AC power supply 1 is double-voltage rectified by the rectifier 2 and the capacitors 3 and 4, and a DC voltage of about 280 V is applied between the PN terminals of the inverter circuit 5. The signals are supplied and the signals are output in order from the control circuit 6 to the inverter circuit 5, whereby the washing, rinsing, and spin-drying are sequentially performed, thereby operating as a fully automatic electric washing machine.

In this embodiment, since the inverter circuit 5 is electrically insulated from the inverter circuit 5, it is possible to prevent malfunction of the inverter circuit 5 when external noise is present on the wiring between them. In addition, the inverter circuit 5
In some cases, the noise between the inverter circuit 5 and the wiring between the display and the operation display circuit 7 may be about 1 meter. It is also possible to reduce the generation of radiated noise outside the device, and the noise radiated inside the device leaks again to the power cord connected to the AC power supply 1 by electrostatic coupling or electromagnetic coupling. Accordingly, it is possible to effectively prevent the conduction noise (noise terminal voltage) from increasing.

The inverter circuit 5 and the operation display circuit 7
In the event that the insulation of the wiring between
Since the wiring portion is electrically insulated from the AC power supply 1, there is no fear of electric shock or the like, and a highly safe electric washing machine is realized.

(Embodiment 2) As shown in FIG. 2, a power supply circuit 26 is provided with a switching power supply 27 operating as a flyback converter, and includes a primary winding 28, secondary windings 29, 30, and 31. A high-frequency transformer 32 operating at about 100 kHz is provided, and in series with the primary winding 28,
A switching element 33 using a MOSFET is connected, and is configured to operate by receiving a DC voltage of about 140 V from both ends of the capacitor 4.

The diodes 34, 35, and 36 rectify the output of each secondary winding, and the output of the diodes 34, 35, and 36 is reduced in ripple voltage by electrolytic capacitors 37, 38, and 39.

In this embodiment, since the flyback method is employed, the switching element 33 is turned off during the off period.
Through the diodes 34, 35 and 36, the capacitor 3
7, 38 and 39 are charged.

Here, the secondary windings 29 and 30 are connected in series, but the secondary winding 31 has no electrical contact with the secondary windings 29 and 30. The present invention realizes the first aspect of the present invention by outputting a power supply output electrically insulated to the operation display circuit 7.

The negative input terminal N of the inverter circuit 5 is used as a common terminal, that is, a GND terminal, and the negative terminal of the control circuit 6, that is, a GND terminal is connected thereto.
Further, the first terminal d of the power supply circuit 26 is connected as a common terminal.

A metal film type current detecting resistor 40 having a resistance of 0.22Ω is connected between the common terminal and the negative terminal of the capacitor 4. A DC voltage of about 140 V is input between the second terminal and the first terminal d.

Then, the second terminal a of the power supply circuit 26 is connected to the plus terminal of the capacitor 4, and the control circuit 6 outputs the voltage between the first terminal d and the third terminal c of the power supply circuit 26. It operates by being supplied with a DC voltage of 5V.

Further, a communication circuit 22 for performing digital data communication while ensuring electrical insulation is provided between the control circuit 6 and the operation display circuit 7. The motor 12 is connected to the output terminals U, V, W of the inverter circuit 5 in the same manner as in the first embodiment, and the three-phase armature windings 9, 10, 11
Is provided.

The current detection circuit 41 inputs a voltage value generated in accordance with the current from the left terminal of the current detection resistor 40 from an R terminal. Is output from the AD terminal to the control circuit 6 in proportion to the peak value of. Other configurations are the same as those in the first embodiment.

With the above configuration, as in the first embodiment, the output voltage of the AC power supply 1 is reduced by the rectifier 2 and the capacitor 3,
4 is rectified by the double voltage and the PN of the inverter circuit 5
A DC voltage of about 280 V is supplied between the terminals, and a power supply circuit 26 using a switching power supply 27 supplies power to the control circuit 6 and the operation display circuit 7 that are electrically insulated from separate secondary windings. The signals are output in order from the control circuit 6 to the inverter circuit 5, so that washing, rinsing,
Dehydration is performed sequentially, and it operates as a fully automatic electric washing machine.

For example, when the amount of cloth becomes excessive, a high output voltage corresponding to the peak value of the voltage generated between both ends of the current detection resistor 40 is supplied from the AD terminal of the current detection circuit 41 to the control circuit 6. The control circuit 6 performs the feedback control of reducing the PWM duty value with respect to the inverter circuit 5 so that the operation is performed while preventing an excessive current from flowing through the inverter circuit 5 and the electric motor 12.

In this embodiment, the power supply circuit 26 is constituted by using the switching power supply 27, and the secondary winding of the high-frequency transformer 32 is separately provided in the control circuit 6 and the operation display circuit 7, and Although the communication circuit 22 is capable of transmitting digital signals while ensuring electrical insulation, the communication circuit 22 is not so configured. The configuration in which the power supply of the power supply circuit 26 and the operation display circuit 7 are taken out in parallel is also within the scope of claim 2. In particular, while the configuration of the power supply circuit 26 is relatively simple, an inverter circuit is provided from both ends of the current detection resistor 40. The effect that the current detection at the input portion of No. 5 can be performed with a relatively simple configuration can be obtained.

(Embodiment 3) As shown in FIG. 3, the decoupling capacitor 42 is composed of a metallized polyester type capacitor having a capacitance of 0.033 μF, and a first terminal d of the switching power supply 27 and a second terminal d. Are connected between the terminals a. Other configurations are the same as those of the second embodiment.

FIG. 4 is a partial circuit diagram illustrating a loop of a current flowing through the current detection resistor 40. As shown in FIG. 4, the inverter circuit 5 has a voltage VC2 applied across the series circuit of the capacitors 3 and 4 between the P terminal and the N terminal at about 280 V DC. A current IINV indicated by a thick line flows through the capacitors 3 and 4, the inverter circuit 5, and the current detection resistor 40.

On the other hand, a power supply circuit 26 constituted by a switching power supply 27 has a first terminal d (GND).
Since 1) uses a common terminal for the input and the output, the circuit configuration inside the switching power supply 27 is simple and low-cost. Without providing any other means, the feedback control can be performed by directly connecting to the switching element 33, and the power supply circuit 26 having highly accurate constant voltage characteristics can be realized.

However, for that purpose, as shown in FIG.
1 flowing through the primary winding 28 and the switching element 33
The next current flows through the capacitor 4 and the power supply circuit 26 and flows from the d terminal of the power supply circuit 26 to the current detection resistor 40. Therefore, by detecting the voltage of the left terminal of the current detection resistor 40 by the current detection circuit 41, Even if an attempt is made to detect the current IINV flowing through the inverter circuit 5, an error is caused by the primary current of the power supply circuit 26.

However, since the power consumption (watt value) of the power supply circuit 26 is generally smaller than the magnitude of the current value I INV flowing through the inverter circuit 5, the average value of the power supply circuit 26 The ratio of the error due to the current is low.

However, in a general inverter circuit, when the inverter circuit 5 of PWM control which is often used is used, in order to detect the current of the motor 12, the peak value of the voltage of the current detection resistor 40 (the bottom value in terms of polarity). Is detected, the operation frequency of the switching power supply 27 constituting the power supply circuit 26 is 100 kHz,
The peak value of the harmonic component is added, resulting in a large error in the operation of the current detection circuit 41.

Here, the decoupling capacitor 42
Has a function of bypassing particularly high frequency components, so that a steep peak current generated by the switching operation of the power supply circuit 26
The current detection circuit 41 can detect the current with high accuracy. For example, the protection operation due to the stop of the inverter circuit 5 when an overcurrent flows may malfunction, and the current detection circuit 41 may operate normally. Electric motor 1
It is also possible to prevent such a problem that the rotation of the second motor stops.

In the present embodiment, the decoupling capacitor 42 having a capacitance of 0.033 μF is used. For example, in the present embodiment, the optimum value may be determined by a noise prevention filter circuit or the like provided in the current detection circuit 41 in consideration of necessary responsiveness and the like.

In this embodiment, the power supply circuit 26
Is connected to the positive terminal of the capacitor 4 on the low potential side, which is rectified by voltage doubler, so that a voltage of about 140 V is input to operate. It is not necessary to use the voltage of the low potential side capacitor 4 as the input voltage of the power supply circuit 26. For example, the second terminal a of the power supply circuit 26 is connected to the plus terminal of the high potential side capacitor 3 and connected. And about 28
The same effect can be obtained in a configuration in which a DC voltage of 0 V is input.

In the first to third embodiments, the motor 12 is a DC brushless motor using a permanent magnet for the rotor, but is particularly limited to such a structure. Instead, an induction motor, a switch reluctance motor, a configuration called a hysteresis motor may be used.
The effect is the same.

In each of the embodiments, the inverter circuit 5 and the motor 12 have a three-phase structure. However, the invention is not limited to the three-phase structure. As a configuration of a total of four stones including two potential-side switching elements and two low-potential-side switching elements, a motor having a single-phase winding may also be used as the electric motor 12.

[0049]

As described above, according to the first aspect of the present invention, an AC power supply, a rectifier for rectifying the AC power, a capacitor connected to an output of the rectifier, and an output of the rectifier. A control circuit for controlling the inverter circuit, an operation display circuit, and a power supply circuit for supplying power to the control circuit and the operation display circuit, wherein the power supply circuit includes a plurality of secondary circuits. A power supply is provided to the control circuit and the operation display circuit from separate secondary windings, and the operation display circuit is electrically insulated, so that radiation to other electric devices is provided. It can suppress the emission of noise and conduction noise, prevent malfunction of the device due to external noise, and prevent electric shock even if the user touches if the operation display circuit is broken.

According to the second aspect of the present invention, an AC power supply, a rectifier for rectifying the AC power, a capacitor connected to an output of the rectifier, and an inverter circuit connected to an output of the rectifier, A control circuit for controlling the inverter circuit; and a power supply circuit for supplying power to the control circuit. A common terminal is used as a negative input terminal of the inverter circuit, a negative terminal of the control circuit, and a first terminal of the power supply circuit. And a current detection resistor connected between the common terminal and the negative terminal of the capacitor, and the power supply circuit receives a voltage between a second terminal and the first terminal as an input. Switching power supply,
The second terminal of the power supply circuit is connected to another terminal of the capacitor, and the control circuit is supplied with a DC voltage output between the first terminal and the third terminal of the power supply circuit. , The power supply circuit can have a relatively simple structure in which the first terminal is a common terminal for input and output, and the input current of the inverter can be detected by the current detection resistor. It can be realized with a relatively simple configuration.

According to the third aspect of the present invention, since the power supply circuit has the decoupling capacitor between the first terminal and the second terminal, the input current of the inverter is controlled by the current detection resistor. It is possible to realize an electric washing machine capable of performing detection, and in addition, to stabilize the voltage input to the power supply circuit and supply a high-frequency ripple current flowing from the decoupling capacitor to the power supply circuit. In addition, the high-frequency ripple current flowing through the current detection resistor can be reduced, and highly accurate current detection can be performed.

[Brief description of the drawings]

FIG. 1 is a partially block circuit diagram of an electric washing machine according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a partially-blocked electric washing machine according to a second embodiment of the present invention.

FIG. 3 is a partially block diagram of an electric washing machine according to a third embodiment of the present invention.

FIG. 4 is a main part circuit diagram illustrating a current flowing through a current detection resistor of the electric washing machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectifier 3 Capacitor 4 Capacitor 5 Inverter circuit 6 Control circuit 7 Operation display circuit 8 Power supply circuit 13 Transformer 20 Secondary winding 21 Secondary winding

Continued on the front page (72) Inventor Hideki Ryuko 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 3B155 BA23 HB10 HC04 HC06 HC07 KB08 KB22 LC08 LC15 MA09

Claims (3)

[Claims] An AC power supply; a rectifier for rectifying the AC power; a capacitor connected to an output of the rectifier; an inverter circuit connected to an output of the rectifier; a control circuit for controlling the inverter circuit; A display circuit, a power supply circuit for supplying power to the control circuit and the operation display circuit, the power supply circuit includes a transformer having a plurality of secondary windings, and the control circuit and the operation display circuit Is an electric washing machine in which power is supplied from separate secondary windings and the operation display circuit is electrically insulated. 2. An AC power supply, a rectifier for rectifying the AC power, a capacitor connected to an output of the rectifier, an inverter circuit connected to an output of the rectifier, a control circuit for controlling the inverter circuit, A power supply circuit for supplying power to a control circuit, wherein a negative input terminal of the inverter circuit, a negative terminal of the control circuit, and a first terminal of the power supply circuit are connected as a common terminal, and the common terminal and the capacitor are connected. A current detection resistor connected between the negative terminals of the
And a switching power supply that receives a voltage between the terminal of the power supply circuit and the first terminal, the second terminal of the power supply circuit is connected to another terminal of the capacitor, and the control circuit is An electric washing machine configured to operate by being supplied with a DC voltage output between the first terminal and the third terminal. 3. The electric washing machine according to claim 2, wherein the power supply circuit has a decoupling capacitor between the first terminal and the second terminal.