JPH05228291A - Washing machine - Google Patents

Abstract

PURPOSE:To surely start a motor having a variable rotating speed by applying all the power voltage to the motor at the time of a start, and variably PWM- controlling the voltage applied to the motor after the start. CONSTITUTION:A microcomputer 28 feeds the PWM control signal to a transistor 20 via a transistor drive circuit 34 to on/off-control it, and the voltage applied to a motor 5 is variably PWM-controlled. When the motor 5 is rotatively driven in the positive rotational direction, the excitation direction to the motor 5 is switched to the positive rotation side by a positive/reverse rotation switching circuit, the PWM control signal having the duty of 100% is fed to the transistor 20, and 100% of the power voltage of a commercial AC power source 15 is applied to the motor 5 when the motor 5 is started. The duty of the PWM control signal is changed after the rotating speed reaches the target rotating speed, and feedback control is performed so that the rotating speed of the motor 5 is made nearly equal to the target rotating speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine constructed such that an agitator for washing is rotationally driven by a motor.

[0002]

2. Description of the Related Art In a washing machine, an induction motor is generally used as a motor for rotationally driving an agitator for washing or a basket for dehydration. At the time of washing, the induction motor is rotated normally and reversely. , A normal water flow and a reverse water flow are generated. In this case, the optimum washing water flow is generated by changing the strength of the water flow according to the type of laundry. In the conventional configuration, specifically,
The strength of the water flow is changed by appropriately changing the on-time for rotating the induction motor forward and backward and the off-time for changing the rotation direction of the induction motor.

[0003]

However, in the above-mentioned conventional configuration, since the induction motor is rotated at the maximum rotation speed while the induction motor is on, the strength of the water flow generated during that period is After all it becomes the maximum. For this reason, it was not possible to generate a water flow having a strength corresponding to the type of laundry.

On the other hand, it is conceivable that the rotational speed of the induction motor is variably controlled to generate an optimum washing water flow according to the type of laundry. In this case, as a configuration for variably controlling the rotation speed of the induction motor, a configuration in which the voltage applied to the induction motor is PWM-controlled to be variable can be considered.

In this PWM control configuration, the rotation speed of the induction motor can be set to a desired rotation speed, so that an optimum wash water flow can be generated according to the type of laundry. However, in the above configuration, when the PWM control is performed so that the voltage applied to the induction motor is lowered in order to rotate the induction motor at a low speed, the starting torque of the induction motor becomes small, so that the motor cannot be started. is there. Therefore, when the water flow intensity of the washing machine is variably controlled, the PWM control configuration cannot be used.

Therefore, an object of the present invention is to provide a washing machine which is capable of variably controlling the rotation speed of the motor by PWM-controlling the voltage applied to the motor, and which is capable of reliably starting the motor. There is

[0007]

A washing machine of the present invention is a washing machine constructed such that a stirring member for washing is rotationally driven by a motor, and a rotation speed detecting means for detecting a rotation speed of the motor is provided. In addition, at the time of startup, a voltage of 100% of the power supply voltage is applied to the motor, and after startup,
The present invention is characterized in that a rotation speed control means for controlling the detected rotation speed detected by the rotation speed detection means to be equal to a target rotation speed by PWM controlling the voltage applied to the motor to vary ..

[0008]

According to the above means, at the time of start-up, the voltage of 100% of the power supply voltage is applied to the motor.
The motor can be surely started. After the startup, the voltage applied to the motor is PWM-controlled to vary so that the detected rotation speed detected by the rotation speed detection means is controlled to be equal to the target rotation speed. It is possible to set the speed to the desired rotation speed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a combined washing machine for dehydration will be described below with reference to the drawings. First, in FIG. 2 showing the configuration of the entire washing machine, a water receiving tub 2 is elastically supported in an outer box 1 via an elastic suspension mechanism (not shown). In the water receiving tank 2, a rotating tank 3 which is a washing tank and a dehydration basket is arranged. An agitator 4 for washing is disposed on the inner bottom of the rotary tub 3.

At the outer bottom of the water receiving tank 2, a motor 5 for washing and dewatering operation and a mechanism portion 6 are provided. The motor 5 is, for example, a single-phase induction motor. Then, the mechanism unit 6 decelerates the rotation of the motor 5 during washing and transmits it to only the stirring body 4 to rotate it, and transmits the rotation of the motor 5 to the stirring body 4 and the rotary tub 3 during dehydration. Then, both are integrally rotated at high speed.

A drain valve 8 and a drain pipe 9 are provided at the drain port 7 formed at the bottom of the water receiving tank 2. An air trap 10 is provided adjacent to the drainage port 7. The air trap 10 includes a water level sensor 11
Are connected via the air tube 12. The water level sensor 11 is arranged in the rear portion of the upper cover 13 of the outer box 1. In addition, at the rear of this upper cover 13,
A water supply valve 14 is provided.

Now, in FIG. 3 showing the electrical configuration, power source buses 16 and 17 are derived from a commercial AC power source 15. A motor 5 is provided between these power supply buses 16 and 17.
Also, a switching circuit 18 for connecting and disconnecting the motor 5 to perform PWM control is connected. The switching circuit 18 includes a bridge-type full-wave rectifier circuit 19 and a switching element such as an NPN-type transistor 20.
It consists of and. By controlling the transistor 20 to be turned on and off, the motor 5 is cut off.

A flywheel circuit 21 is connected in parallel between both terminals of the motor 5. The flywheel circuit 21 includes a series circuit composed of a flywheel diode 22 having a polarity shown in the figure and a switching means 23 for turning on and off the diode 22, a flywheel diode 24 having a polarity opposite to that of the flywheel diode 22 and the diode 24. It is configured to be connected in parallel with a series circuit composed of switching means 25 for turning off and on.

In this case, when the transistor 20 of the switching circuit 18 is turned off, the flywheel circuit 21 energizes one of the flywheel diodes 22 and 24 in accordance with the sign of the AC voltage of the commercial AC power supply 15. By doing so, the energy stored in the inductance of the motor 5 is discharged and returned to the power supply side. A noise absorbing capacitor 26 is connected between the power supply buses 16 and 17 derived from the commercial AC power supply 15.

On the other hand, between the power source buses 16 and 17,
A DC power supply circuit 27 is connected, and the DC power supply circuit 27 is configured to apply a DC constant voltage to a control circuit such as a microcomputer 28. This microcomputer 28 has a program for controlling the washing and dehydrating operations stored in its internal memory. The microcomputer 28 has a function of rotation speed control means.

Further, the microcomputer 28 has various switch signals from an input circuit 29 provided with various switches provided on an operation panel (not shown) and the water level sensor 1.
1 receives the water level detection signal and the rotation speed detection means 30 for detecting the rotation speed of the motor 5. The rotation speed detecting means 30 is composed of, for example, a rotary encoder.

The microcomputer 28 has a display circuit 3 having various display portions provided on the operation panel.
1 is drive-controlled, and the drain valve 8 and the water supply valve 14 are drive-controlled via the drive circuits 32 and 33, respectively. Further, the microcomputer 28 is
By controlling the on / off of the transistor 20 via the transistor drive circuit 34, the motor 5 is turned on / off. Particularly, in this case, the microcomputer 28 connects the transistor 20 to the transistor drive circuit 3
The voltage applied to the motor 5 is PWM-controlled to be variable by applying a PWM control signal via 4 to perform on-off control.

The above PWM control will be briefly described below with reference to FIGS. 5, 6 and 7. Now, when a PWM control signal (see FIG. 5A) having a duty of 50% is applied to the transistor 20, the voltage V applied to the motor 5 is increased.
Changes on and off as shown in FIG. Here, the average voltage Va applied to the motor 5 is as shown in FIG.
As shown by the broken line. The duty of the PWM control signal is a ratio of ON time t1 / (ON time t1 + OFF time t2).

When a PWM control signal (see FIG. 6A) having a duty of 25% is given to the transistor 20,
The voltage V applied to the motor 5 changes on and off as shown in FIG. Here, the average voltage Va applied to the motor 5 decreases as shown by the broken line in FIG.

On the other hand, the rotational speed of the motor 5 and the torque of the motor 5 have a relationship as shown in FIG. Here, the torque curves T1, T2, T3 are V when the average voltage Va applied to the motor 5 is high, when Va is medium,
The case where a is low is shown. As is apparent from FIG. 7, if the average voltage Va is lowered, the rotation speed of the motor 5 can be lowered accordingly. That is,
By changing the duty of the PWM control signal,
The rotation speed of the motor 5 is variable.

Although not shown in FIG. 3, the motor 5
There is provided a forward / reverse rotation switching circuit for reversing the rotation direction of the. The forward / reverse rotation switching circuit is configured to rotate the motor 5 in the forward and reverse directions by switching the direction of energizing the main coil and the auxiliary coil of the motor 5.

Next, the operation of the above structure will be described with reference to FIGS. The flow chart of FIG. 1 schematically shows the control contents of the rotation speed control means of the microcomputer 28. FIG. 1 shows a case where the motor 5 is rotationally driven in the forward rotation direction, that is, a case where washing is performed with a forward rotation water flow. The washing operation is an operation in which the washing with the normal rotation water flow and the washing with the reverse rotation water flow are alternately repeated for a set washing operation time. The washing time with the normal rotation water flow (usually, the washing time with the reverse rotation water flow is the same time) is set in advance.

Therefore, as shown in FIG. 1, when the motor 5 is rotationally driven in the forward rotation direction, with the forward / reverse rotation switching circuit switching the energization direction to the motor 5 to the forward rotation side,
First, by applying a PWM control signal with a duty of 100% to the transistor 20 (step S1), 100% of the power supply voltage of the commercial AC power supply 15 is started when the motor 5 is started.
Is applied to the motor 5. As a result, the motor 5 is activated and the rotation speed thereof increases (see FIG. 4).

In this case, the voltage of 100% of the power supply voltage is applied to the motor 5 until the rotation speed of the motor 5 reaches the target rotation speed. After the rotation speed of the motor 5 reaches the target rotation speed, the duty of the PWM control signal is changed to perform feedback control so that the rotation speed of the motor 5 becomes substantially equal to the target rotation speed.

Specifically, first, it is determined whether or not the washing time by the normal rotation water flow has ended (step S2). In this case, since the washing time by the normal rotation water flow has not ended, in step S2. Proceed to "NO". Then, it is determined whether or not the detected rotation speed of the motor 5 detected by the rotation speed detection means 30 has reached the target rotation speed (step S).
3). Here, when the detected rotation speed of the motor 5 has not reached the target rotation speed, the process proceeds to “NO” in step S3, and 100% of the power supply voltage is continuously applied to the motor 5.

On the other hand, when the detected rotation speed of the motor 5 reaches the target rotation speed in step S3, the process proceeds to "YES" in step S3 and the duty of the PWM control signal is changed to change the duty of the motor 5. The rotation speed is controlled to be equal to the target rotation speed (step S
4).

In this case, specifically, when the rotation speed of the motor 5 becomes higher than the target rotation speed, the PWM
When the duty of the control signal is set small and the rotation speed of the motor 5 becomes lower than the target rotation speed, PW
The duty of the M control signal is set to a large value so that the rotation speed of the motor 5 is controlled to be kept substantially equal to the target rotation speed (see FIG. 4).

After that, when the washing time by the normal rotation water flow ends, the process proceeds to "YES" in step S2, and the motor 5
Stop energizing the. Then, after a lapse of a predetermined motor stop period, the forward / reverse rotation switching circuit switches the energization direction to the motor 5 to the reverse rotation side, and washing with the reverse rotation water flow is performed. The washing with the reverse rotation water flow is controlled in substantially the same manner as the washing with the normal rotation water flow described above. Hereinafter, the operation in which the washing with the normal rotation water flow and the washing with the reverse rotation water flow are alternately repeated is performed for the set washing operation time.

After the washing operation is completed, the rinsing operation is performed, and the rinsing operation is also configured to be controlled in substantially the same manner as the above-described washing operation.

According to the present embodiment having such a configuration, since the voltage of 100% of the power supply voltage is applied to the motor 5 at the time of starting, the motor 5 can be surely started. After the startup, the voltage applied to the motor 5 is PWM-controlled to vary so that the detected rotation speed detected by the rotation speed detection unit 30 is controlled to be equal to the target rotation speed. It becomes possible to set the rotation speed of 5 to a desired rotation speed.
Therefore, it is possible to generate a wash water flow having an optimum strength according to the type of laundry, that is, the cloth quality, improve the cleaning performance, and prevent damage to the cloth.

When washing with a weak water flow, the motor 5 can be rotated at a low speed.
The noise generated from the washing machine can be reduced, and the noise of the entire washing machine can be reduced.

In the above embodiment, 100% of the power supply voltage is applied to the motor 5 from the time of startup until the target rotational speed is reached. However, the present invention is not limited to this, and only during startup, for example. A configuration may be adopted in which a voltage of 100% of the power supply voltage is applied (only for a set time after startup). Also,
In the above embodiment, the induction motor is applied, but instead of this, a DC motor may be applied.

[0033]

As is apparent from the above description, the present invention is configured to apply a voltage of 100% of the power supply voltage to the motor at the time of starting, so that the motor can be started reliably and the starting can be started. After that, the voltage applied to the motor is PWM
By controlling and varying the rotation speed, it is possible to set the rotation speed of the motor to a desired rotation speed.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

[Figure 2] Vertical side view of the entire washing machine

[Fig. 3] Electric circuit diagram

FIG. 4 is a graph showing a change in duty of a PWM control signal and a graph showing a change in rotation speed of a motor.

FIG. 5 is a graph showing a change in a PWM control signal and a graph showing a change in a voltage applied to a motor.

FIG. 6 is a graph showing a change in a PWM control signal having a different duty and a graph showing a change in a voltage applied to a motor.

FIG. 7 is a graph showing the relationship between motor rotation speed and torque.

[Explanation of symbols]

1 is an outer box, 3 is a rotary tank, 4 is a stirrer, 5 is a motor, 15
Is a commercial AC power supply, 18 is a switching circuit, 20 is a transistor, 28 is a microcomputer (rotational speed control means), and 30 is rotational speed detection means.

Claims (1)

[Claims] 1. A washing machine configured to rotationally drive a stirring body for washing by a motor, wherein a rotation speed detecting means for detecting a rotation speed of the motor and a power supply voltage of 100 to the motor at the time of starting. % Voltage is applied, and after starting, the voltage applied to the motor is PWM
And a rotation speed control means for controlling so that the rotation speed detected by the rotation speed detection means becomes equal to the target rotation speed by controlling and varying.