JPS6324987A - Motor driver of washing machine - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a motor drive device for a washing machine or the like that drives a motor for rotating a pulsator or the like in forward and reverse directions.

(Prior Art) Generally, in a washing machine, a pulsator is rotated forward and reverse at a predetermined period to improve cleaning performance. To do this, a single-phase induction motor capable of forward and reverse rotation is used as the pulsator drive motor, and the forward rotation terminal is energized for a predetermined period of time to cause the motor to rotate forward, and then the motor is decelerated after a predetermined power-off period. Then, the cycle of energizing the reversing terminal for a predetermined period of time to reverse the motor is repeated.

(Problem to be solved by the invention) However, with the above configuration, depending on the inertia of the load, the motor does not completely stop within the power-off period, and the reverse terminal is energized while the motor is rotating forward at low speed. Sometimes it happens. In this case, the reverse torque generated by the motor causes an impact force to act on the motor and its surroundings, making it necessary to provide sufficient structural reinforcement, or placing an excessive burden on the motor, shortening its lifespan. This results in the problem of

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a motor drive device for a washing machine or the like that can reliably stop the motor before reversing the motor and prevent reverse torque from acting on the motor while it is rotating.

[Structure of the Invention] (Means for Solving the Problems) A motor drive device for a washing machine or the like according to the present invention has a forward energization period for rotating the motor in the forward direction, and a reverse energization period for rotating the motor in the reverse direction. The feature is that DC braking is performed by applying a DC voltage to the windings of the motor.

(Function) Since DC braking is applied by applying DC voltage to the windings of the motor, the motor can be decelerated more rapidly than when deceleration is simply caused by a power cut.

(Example) A first example in which the present invention is applied to a washing machine will be described below with reference to FIGS. 1 and 2.

Reference numeral 1 designates a motor for driving a pulsator (not shown), which is a single-phase induction motor that is equipped with first and second windings 2 and 3 and is capable of forward and reverse rotation. A common terminal 1c of this motor 1 is connected to one bus bar 4a of a power source 4, and a phase splitting capacitor 5 is connected between the forward rotation terminal 1f and the reverse rotation terminal 1b. Further, the forward rotation terminal 1f and the reverse rotation terminal 1b are respectively connected to the other bus bar 4b of the power source 4 via the first and second triacs 6.7, and the bus bar 4b is connected to the motor via the thyristor 8 with the polarity shown. It is connected to the normal rotation terminal 1f. Reference numeral 9 denotes a control circuit that controls the gates of each of the triacs 6 and 7 and the thyristor 8, which controls the triac 6 at the following timing.
．． 7 and thyristor 8 are on/off controlled.

That is, when the washing process is started, as shown in FIG. 2(A), the forward rotation energization period begins, and only the first triac 6 is turned on for a predetermined period of time based on the gate signal from the control circuit 9. do. When the first triac 6 is turned on, an AC voltage from the power supply 4 is applied to the forward rotation terminal 1f of the motor 1, and as shown in FIG. 2(B), the motor 1 starts in the forward direction and increases its rotation speed. let Then, simultaneously with the end of the normal rotation energization period, the first triac 6 is turned off by a gate signal from the control circuit 9, and
Thyristor 8 is turned on.

As a result, a half-wave DC voltage is applied to the forward rotation terminal 1f of the motor 1, so that a DC current flows through the first winding 2 and DC braking is applied. Therefore, the motor 1 rapidly decelerates and comes to a stop (see FIG. 2(B)). After this, the current flow period for reverse rotation begins, and the second
Only the triac 7 is turned on, and the AC voltage from the power supply 4 is applied to the reverse rotation terminal 1b of the motor 1, and the motor 1 is started in the reverse direction to increase its rotational speed. and,
When the reversal energization period ends, the second triac 7 is turned off and the thyristor 8 is turned on again. Therefore, DC current flows through the second winding 2 of the motor 1 again, applying DC braking, and the motor 1 rapidly decelerates and comes to a stop. Thereafter, this process is repeated for the washing process time to complete the washing process.

As described above, in this embodiment, a DC voltage is applied to the second winding 2 of the motor 1 between the forward rotation energization period and the reverse rotation energization period to perform DC braking, so that the forward rotation is not possible. After reversal, motor 1 decelerates rapidly and by the time the reversal operation starts, motor 1 has completely stopped and motor 1
will start the reversing operation from a completely stopped state. For this reason, an excessive load may be placed on the motor 1, or the motor 1 may
It is possible to reliably prevent impact force from acting on the engine, drive mechanism, etc., or generation of noise.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3 to 5. The difference from the first embodiment is that the DC voltage applied to the second winding 2 is gradually increased for DC braking. For this purpose, instead of the thyristor 8 in the first embodiment, as shown in FIG. A capacitor 12 is connected between the common connection point of the resistor 10 and the second thyristor 11 and the bus bar 4a. The other configurations are the same as those in the first embodiment, so the same reference numerals are given and the explanation will be omitted.

In the above configuration, as shown in FIG. 4, the point where the first and second triacs 6.7 are turned on alternately is
Although it is similar to the embodiment, each of the first and second cycle risks 9.11 is applied between the forward rotation energization period and the reverse rotation energization period.
are turned on at the same time, and the second thyristor 11 is turned off later than the first thyristor 9. With such on/off timing, the resistor 10 and capacitor 12 form an integral circuit, so during the period when DC braking is performed, the voltage applied to the second winding 2 of the motor 1 is as shown in FIG. -F gradually increases. In this way, even under the circumstances that in the DC braking system, the braking force increases as the rotational speed of the motor increases, it is possible to prevent excessive braking force from being applied at the beginning of braking and apply gentle braking. Can be done. Furthermore, the second
The reason why the turn-off of the first thyristor 11 is delayed from that of the first thyristor 9 is so that the capacitor 12 is completely discharged at the end of braking so that the applied voltage can rise from approximately O when the next braking starts. This is to do so.

Furthermore, the present invention is not limited to the embodiments described above and shown in the drawings; for example, in order to gradually increase the DC voltage for DC braking, the thyristor 8 of the first embodiment may be phase-controlled. The control angle may be gradually increased from the start of braking.

Furthermore, the DC voltage for braking may be applied to all windings of the motor. In addition, the present invention is applicable to a washing machine configured to rotate a container-shaped agitator provided at the bottom of a washing tank forward and backward at a predetermined cycle, and a drum dryer configured to rotate a drum forward and backward at a predetermined cycle. Various modifications can be made without departing from the spirit of the invention, such as application to a motor drive device.

[Effects of the Invention] As described above, the present invention is characterized in that DC braking is performed by applying a DC voltage to the windings of the motor between the forward rotation energization period and the reverse rotation energization period. However, as a result, it is possible to completely stop the motor before reversing the motor and reliably prevent the application of reverse torque during rotation, which is an excellent effect.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a circuit diagram, FIG. 2 is a time chart shown together with a motor speed change diagram, and FIGS. 3 to 5 are a diagram of a first embodiment of the present invention. The second embodiment is shown, FIG. 3 is a circuit diagram, FIG. 4 is a time chart, and FIG.
The figure is a voltage waveform diagram. In the drawings, 1 is a motor, and 2 is a first winding (winding).

Claims (1)

[Scope of Claims] 1. In a device that drives a motor for forward and reverse rotation of a pulsator or the like of a washing machine, a forward rotation energization period for forward rotation of the motor and a reverse rotation energization period for reverse rotation of the motor are provided. A motor drive device for a washing machine or the like, characterized in that DC braking is performed by applying a DC voltage to the windings of the motor. 2. The motor drive device for a washing machine or the like as set forth in claim 1, wherein the DC voltage for DC braking is applied so as to gradually increase.