JPH11276781A - Inverter washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electromotive force generated by nnertial revolution of a motor at the time of controlling the motor from being wastfully consumed, in an inverter washing machine. SOLUTION: By connecting a power storage means 33 and a charge/discharge means 34 (switching element, or the like) in parallel to a smoothing capacitor 32 and controlling charge and discharge by arbitrary timing from a control part 43 via charge/discharge means 34a, 34b, electric power by inertial revolution just after a motor is stopped is charged in a 'washing mode', for instance, electric power is discharged at the time of an operation, the starting of the motor is more smoothly performed and generated power of the motor is efficiently used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter washing machine provided with inverter means for varying the rotation speed of an electric motor, and more particularly to switching of a smoothed rectified voltage obtained by rectifying an alternating current to change an output voltage to control the rotation speed. The present invention relates to an energy saving technology for an inverter washing machine.

[0002]

2. Description of the Related Art A conventional general washing machine uses a single-phase induction motor and rotates a pulsator or a dehydration tub at a rotation speed determined by the frequency of a commercial power supply. A reduction gear, a pulley, and a belt are used to match the desired rotation speed and torque, and the rotation speed of the pulsator and dehydration tub is switched using a clutch to produce two types of rotation speed. .

[0003] Further, as a device for changing the rotation speed, O
N / OFF method, phase control method and the like have been proposed. However, they have disadvantages such as large noise and vibration and narrow variable width. Recently, inverter control method using a three-phase motor has been proposed to eliminate this disadvantage. Washing machines have been proposed.

FIG. 2 shows a schematic configuration of a conventional inverter washing machine. The washing machine 1 is a one-tank type fully automatic washing machine,
A dewatering tub 2 also serving as a washing tub and a water tub 3 are provided inside the main body. The water tank 3 is suspended from the main body by a suspension unit 4, and the dewatering tank 2 is rotatably installed inside the water tank. A pulsator 5 is provided at the bottom of the dewatering tank 2. The lid 6 is provided so as to be freely opened and closed for taking in and out laundry.

[0005] A transmission mechanism 8 having a motor 7 and a rotating shaft is fixed to a lower portion of the water tank 3. The rotation of the motor 7 is controlled by the belt 1 hung between a motor pulley 9 provided on the rotating shaft and a gear pulley 10 provided on the transmission rotating shaft.
1 to the transmission mechanism 8. The transmission mechanism 8 has a built-in reduction gear and clutch, and reduces the number of rotations of the motor to transmit the rotation to the dewatering tank 2 and the pulsator 5.

An operation unit 12 and a display unit 1 are provided on an upper part of the main body 1.
3, lid sensor 1 for detecting opening / closing of buzzer 14 and lid 6
The water tank 3 is provided with a water level sensor 16 for detecting the water level in the water tank. Further, a main control unit 17 composed of a microcomputer for controlling the entire operation of the washing machine is provided below the operation unit 12, and controls the rotation drive of the motor on the top plate separately from the main control unit 17. And a sub-control unit 18 composed of a microcomputer for controlling the rotation of the motor via the driving means.

FIG. 3 schematically shows a configuration relating to the operation of the washing machine. The main control unit 17 stores the contents of the operation of each step such as washing, rinsing, and dehydration, and a program describing an execution order of the steps, that is, a processing course, and according to the program, the water supply valve 19 and the drain valve 20 are stored. Opening / closing and switching control of the transmission destination of the rotation of the motor in the transmission mechanism are performed, and the rotation of the motor 7 is controlled via the sub-control unit 18.

As shown in FIG. 4, a three-phase four-pole DC brushless motor is used as the motor 7, and six switching means 36a to 36c and 37a to 37c (hereinafter abbreviated as 36 and 37) are constituted by a three-phase full-wave bridge. Inverter means 3
The drive power is supplied from the motor 5 to the motor 7.
The main controller 17 transmits control data necessary for controlling the rotation of the motor 7 to the sub controller together with the synchronization clock 21. After reading the signal, the sub control unit transmits the signal 23 in synchronization with the clock.

Next, the configuration of the sub control unit 18 will be described with reference to FIG. The commercial power supply 30 is converted into a pulsating DC by the rectifier 31. A diode bridge is used for the rectifier 31. The DC voltage rectified by the rectifier 31 is smoothed by a smoothing capacitor 32. Then, this DC power is supplied to the inverter means 35, and is converted into three-phase AC by the switching means 36 and 37. When the three-phase AC drive current is supplied to the DC brushless motor 7, the DC brushless motor 7 rotates.

A pair of arms corresponding to three phases are formed as switching means 36 and 37 in the inverter means 35, and six transistors are provided as switching elements. The three transistors connected to the (+) side of the smoothing capacitor 32 are called an upper arm 36,
The three transistors connected to the (-) side are referred to as a lower arm 37.

The diodes 38a to 38c and 39a to 39c (hereinafter abbreviated as 38 and 39) are connected in parallel to the six transistors, respectively. Upper arm 3
6 and the lower arm 37 are connected to the respective phases (U phase, V phase, W phase) of the armature winding of the DC brushless motor. A drive circuit 41 is connected to each of the bases of the transistors, and drives the transistors according to a signal of a microcomputer of the control unit 43.

In this inverter control system, a three-phase motor (induction motor or DC brushless motor) is used instead of the conventionally used single-phase induction motor. It was necessary to apply. In order to output this three-phase AC waveform, three sets of half-bridge configurations in which two switching means 36 and 37 such as power transistors and IGBTs are connected in series to the inverter means 35 are provided. It has a full-wave bridge configuration.

[0013] A DC brushless motor may be used as a motor for the three-phase inverter type washing machine in order to reduce noise and reduce vibration. However, this DC brushless motor generally has a three-phase armature winding. A line is provided with a rotor formed of a permanent magnet, and a Hall element for detecting the rotational position of the rotor. Unlike an induction motor, a DC brushless motor converts a three-phase AC into a three-phase AC based on a signal 42 synchronized with a rotor position detected by the Hall element, and supplies the three-phase AC to a three-phase armature winding. Is to be rotated.

[0014]

Conventionally, in the "wash mode" of such a washing machine, the pulsator 5 is rotated forward,
The machine is running so that it rotates intermittently while repeating stop, reverse, and stop. At this time, when the motor 7 is stopped, the switching means 3 for motor drive shown in FIG.
When all the switches 6 and 37 are turned off, the motor is in a free state, and the DC brushless motor 7 generates electric power by inertial rotation, and smoothes the power through the diodes 38 and 39 connected in parallel to the switching means 36 and 37. Since the charge is returned to the capacitor 32, the charge voltage of the smoothing capacitor 32 increases. Therefore, the capacity of the smoothing capacitor 32 also needs to be set in consideration of the ripple voltage.

Further, the upper arm 3 of the switching means is provided.
Only 6 is turned off, and all the lower arms 37 are turned on, and the regenerative current is consumed. In this case, the power of the DC brushless motor operating as a generator is wasted.

Even in the intermittent operation in the "dehydration mode", the operation, stop, operation, and stop are repeatedly performed intermittently.
Similar to the operation in the "wash mode", the power is returned to the smoothing capacitor when the motor is stopped, and the power generated by the DC brushless motor that operates as a generator is wasted.

[0017]

A description will be given with reference to the sub-control block diagram of FIG. By connecting a power storage means 33 and a charging / discharging means 34 (switching element or the like) in parallel with the smoothing capacitor 32 and controlling charging / discharging at an arbitrary timing from the control section 43 via the charging / discharging means 34, for example, In the "mode", the electric power by the inertial rotation immediately after the stop of the motor is charged, and the electric power is discharged at the time of the operation, so that the motor is started more smoothly and the generated electric power of the motor is used without waste.

Further, by inserting a diode 40 between the smoothing capacitor 32 and the inverter means 35, power is not returned to the smoothing capacitor 32, so that a voltage jump can be prevented and the ripple voltage of the smoothing capacitor 32 can be suppressed. You can do it.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a washing machine to which the present invention is applied will be described with reference to FIG. 1, but the same parts as those in FIG. The feature of FIG. 1 resides in that a configuration surrounded by a dotted line is added.

That is, the DC power supply is
According to the present invention, a power storage means 33 is provided in parallel with the smoothing capacitor 32, DC power is supplied to the inverter means 35 via the charging / discharging means 34, and then the three-phase power is supplied to the switching means 36 and 37. Converted to AC. This 3
The DC brushless motor rotates by supplying the phase AC drive current to the DC brushless motor.

The charging / discharging means 34 is provided, and the charging timing and the discharging timing are arbitrarily controlled by a signal from a microcomputer of the control unit 43.
There is a diode 40 between 4a and 34b, and the circuit does not return the power generated by the motor to the smoothing capacitor.
An example of the switching timing of the charging / discharging means will be described below.

First, in the washing and rinsing step, when the pulsator 5 is intermittently controlled to rotate forward, stop, reversely rotate, and stop, immediately after shifting from the forward rotation to the stop mode, the upper arm 36 and the lower arm 37 are controlled. Both are turned off,
The microcomputer of the sub control unit 44 turns on one side 34b of the charging / discharging means. At that time, the motor is pulsator 5
Becomes a generator by the inertia rotation, and supplies power to the smoothing capacitor 32 through a diode connected in parallel with the transistor, so that the power storage means 33 can be charged.

Then, immediately after shifting from the stop mode to the reverse mode, one side 34a of the charging / discharging means is turned on, and power is supplied to the inverter means 35, so that it can be used as a power source for starting the motor. By performing the same sequence operation immediately after shifting from the reverse rotation mode to the stop mode, the motor operates as a generator and the energy sent to the smoothing capacitor 32 side can be used without waste, and as a result, the total consumption of the washing machine Power can be reduced.

In the intermittent operation of the dehydration step, the operation and the stop of the dehydration tub 2 are intermittently repeated and controlled. The microcomputer of the sub-control unit 44 turns off both the upper arm 36 and the lower arm 37.
N. At that time, the motor is driven by the inertial rotation of the spin-drying tub 2,
The power storage means 33 can be charged because the power is supplied to the smoothing capacitor 32 through the diode 36 connected in parallel with the transistor.

Then, immediately after the transition from the stop mode to the next rotation, one side 34a of the charging / discharging means is turned on, and power is supplied to the inverter means 35, so that it can be used as a power source for starting the motor. As a result, when the motor operates as a generator, the energy sent to the smoothing capacitor 32 can be used without waste, and the power consumption can be reduced.

[0026]

According to the inverter washing machine of the first aspect of the present invention, electric power can be charged from the motor by the inertial rotation when the motor is stopped, and can be discharged when the motor is rotating. be able to. According to the second aspect of the present invention, since a diode is provided between the charging / discharging means 34a and 34b, power is not returned to the smoothing capacitor when the motor is generating power, so that ripple can be reduced. , Reduce the capacity of the smoothing capacitor,
Cost reduction can be achieved.

Since the regenerative current immediately after the motor is stopped can be charged and discharged by the switching element, the regenerative current can be freely controlled when it is desired to use it. For example, when the motor is operated at full power, the regenerative current is discharged. When
Voltage drop can be reduced, power can be used without waste,
Power consumption can be reduced.

According to the inverter washing machine of the third aspect of the present invention, since the electric power charged at the time of starting the motor in the "washing mode" is used, the starting is smooth and the power consumption can be reduced. According to the inverter washing machine of the invention of claim 4,
Since the power charged at the start of the intermittent operation in the "dehydration mode" is used, the start is smooth and the power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a sub control according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of the entire conventional washing machine.

FIG. 3 is a block diagram of a conventional washing machine.

FIG. 4 is a block diagram of a conventional sub control unit.

[Explanation of symbols]

 7 Motor 31 Rectifying means 32 Smoothing capacitor 33 Power storage means 34a, 34b Charge / discharge means 35 Inverter means 40 Diode 43 Control unit

Claims (4)

[Claims] 1. A full-bridge inverter comprising rectifying means for rectifying an AC voltage from a commercial power supply, a smoothing capacitor for smoothing the voltage rectified by the rectifying means, and switching means for inputting the smoothed voltage. Means, a motor whose rotation is controlled by the output of the inverter means, and a control unit for controlling the operation of the inverter means. A regenerative current generated in the inverter means with rotation control of the motor. An inverter washing machine comprising a power storage means for storing power. 2. A current controlling diode is provided between the smoothing capacitor and full-bridge type inverter means,
2. The inverter washing machine according to claim 1, wherein the power storage means is charged and discharged through two switching elements provided on the anode side and the cathode side of the diode. 3. In the washing mode, during repetitive rotation of the motor in the normal rotation and the reverse rotation, the power during the coasting rotation when the one-way rotation drive is turned off is charged in the power storage means, and the charged power is stored in the next cycle. The inverter washing machine according to claim 1 or 2, wherein the inverter is controlled so as to discharge when rotating. 4. In the dehydration mode, when the motor is operated intermittently, the power during the inertial rotation when the rotation drive is turned off is charged in the power storage means, and the charged power is discharged during the next rotation drive. The inverter washing machine according to claim 1 or 2, wherein: