KR100311650B1 - Apparatus for breaking of Washing Machine - Google Patents

Abstract

The present invention relates to a braking control circuit for releasing an overvoltage flow in a system due to back EMF generated by a motor during braking of a washing machine.

Unlike conventional braking resistors for discharging the overvoltage flowing in the system, conventionally, only a rectifier diode is used to construct a converter that receives a commercial (AC) power and converts it into a direct current (DC) power. The transistors are connected in parallel to each other, and the bases of the transistors are controlled by signals generated by the microcomputer to selectively turn on / off a plurality of transistors when the voltage flowing in the system exceeds a predetermined voltage during braking. It is to prevent over voltage over the system by sending the over voltage flowing to the commercial power.

This configuration can eliminate the braking resistor of the prior art, simplifying the circuit configuration, and as the washing machine becomes larger, the braking resistor has a larger capacity, thereby providing a significant contribution to lowering the cost of the product.

Description

Braking Control Circuit of Washing Machine {Apparatus for breaking of Washing Machine}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake control circuit of a washing machine, and more particularly to a circuit configuration capable of releasing overvoltage flowing in a system without using a brake resistor.

In today's washing machines, noise from motion is also important.However, the safety of the user is to stop the operation of the motor in a hurry when the door is unbalanced during dewatering or when the door is opened during dewatering. It is important.

In the related art, various solutions have been proposed to solve the above-mentioned safety problem. A brake control method of the washing machine according to the prior art will be described with reference to FIG. 1 as follows.

The washing machine includes a rectifier 1 for converting and outputting AC power supplied to the system from the outside into DC power as shown in FIG. 1; A motor driver (2) for generating a voltage to drive control the motor (M) when DC power is supplied through the rectifier (1); A voltage detector (3) for sensing a voltage flowing in the system when braking the washing machine and outputting a detection voltage (Vdc); A voltage comparator (4) for comparing the sensed voltage (Vdc) sensed by the voltage detector (3) with a reference voltage (Vref) predetermined in the system; A switching unit (5) determining on / off of the braking resistor (R) according to the comparison result of the voltage comparing unit (4); A sensor (6) for detecting an operating state such as a rotation position and a speed of the motor (M); The microcomputer 7 is configured to receive a control signal from the sensor 6 and logically control the motor driver 2.

In general, the washing process is performed in the order of washing, rinsing, and dehydration. In particular, during the dehydration, the lid of the washing machine is suddenly opened or the washing tank is unbalanced so that the dehydration process needs to be stopped suddenly. If the system is to stop the motor (M).

At this time, since the motor (M) is a brushless DC motor and becomes a load when viewed from the system side during normal washing operation, the motor (M) flows in the direction (I-) in which current is discharged from the rectifier (1) to the motor (M) side. When the motor M is suddenly stopped during the high-speed rotation, the motor M itself becomes a generator and the current I is charged in the direction I +, that is, the current is rectified by the motor M. ), The voltage level of the rectifier 1 rises rapidly.

If the reverse current charged in the rectifier 1 is not discharged, the DC voltage level rises indefinitely to exceed the internal voltage of the internal circuit of the system, causing damage to the entire system. Accordingly, braking means such as voltage sensing section 3, voltage comparing section 4, switching section 5, and braking resistor R are required to release the overvoltage flowing in the system.

The operation of the brake control circuit of the conventional washing machine constructed as described above will be described with reference to FIG. 1 as follows.

First, when AC power is supplied from the outside, the rectifier 1 converts it to a DC voltage, and the motor driver 2 receives the converted DC voltage of the rectifier 1 to drive the motor M.

When the rotating motor M is suddenly stopped, the voltage detector 3 detects a voltage between the rectifier 1 and the motor M and simultaneously transmits the detected voltage Vdc to the voltage comparator 4.

The voltage comparator 4 compares the reference voltage Vref already set by the system with the sensed voltage Vdc sensed by the voltage detector 3 and transmits the comparison result to the switching unit 5.

The switching unit 5 turns on the braking resistor R when the comparison result of the voltage comparing unit 4 determines that the sensing voltage Vdc exceeds the reference voltage Vref. When the braking resistor R is operated, the overvoltage flowing between the rectifying unit 1 and the motor M does not flow to the rectifying unit 1 but passes through the braking resistor R, so that the excess overvoltage flowing in the system is released in the form of thermal energy. This allows the system to be maintained at a constant voltage level.

At this time, the voltage sensing unit 3 continuously detects the voltage level of the system. When it is determined that the sensing voltage between the rectifying unit 1 and the motor M is less than or equal to the reference voltage Vref set by the system, the braking resistor By turning off (R), no current flows through the braking resistor (R) any more, and current flows only through the rectifying section (1).

However, as described above, in the conventional case, since the voltage level of the system is controlled by hardware, the circuit design becomes complicated, and the motor M is connected to the rectifier 1 through the braking resistor R of the motor M. Since the use of the principle of releasing the charged energy as thermal energy, the capacity of the washing machine is increased in the end, thereby increasing the capacity of the braking resistor, thereby complicating component installation and increasing the product cost.

The present invention has been made to solve the problems of the prior art as described above, in place of the braking resistor that releases the overvoltage of the system during braking of the washing machine by changing the configuration of the converter and controlling it in the microcomputer to convert the converter when the overvoltage is detected in the system By designing the overvoltage to escape to the commercial power supply, it is possible to significantly reduce the capacity of the braking resistor or to remove the braking resistor, simplifying the installation, and improving the reliability of the voltage level stability of the system during braking. It also aims to reduce the cost of the product by not using the braking resistor.

1 is a block diagram schematically showing a brake circuit configuration of a washing machine according to the prior art.

Figure 2 is a block diagram schematically showing the configuration of a brake circuit of a washing machine according to the present invention.

3 is a detailed circuit diagram in which a control signal of the microcomputer is applied to the converter according to the present invention;

4 is a timing diagram of a microcomputer control signal for converter control of FIG. 2.

<Explanation of symbols for main parts of the drawings>

1 ............. Rectifier 10 ......... Converter

2,40 ......... Motor drive part 20 ......... smoothing circuit part

3,30 ....... Voltage detection part 5 .......... switching part

6,50 ....... Sensor 7,60 ....... Microcomputer

M .......... Motor R .......... Brake Resistance

Q1 ~ Q10 ..... transistors D1 ~ D10 ..... diode

Features of the braking control circuit of the washing machine according to the present invention to achieve the above object, the converter for converting the voltage supplied from the external to the voltage required in the system, the switching function according to the control signal; A smoothing circuit part which smoothly smoothes the voltage converted by the converter part; A motor driver for generating a voltage for driving the motor by using the output voltage of the smoothing circuit part as an input; A voltage sensing unit positioned between the motor driving unit and the smoothing circuit unit to sense a voltage of a system; And receiving a signal from the voltage sensing unit and the motor and outputting a signal to control the operation of the converter and the motor driving unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram schematically illustrating a configuration of a braking circuit of a washing machine according to the present invention.

First, referring to FIG. 2, the present invention provides a plurality of transistors Q1, Q2, Q3, and Q4 for converting an externally supplied AC voltage into a DC voltage and serving as a switching function when an external control signal is input. ) And a converter 10 comprising a plurality of diodes D1, D2, D3, and D4 connected in parallel to the plurality of transistors, and a smoothing circuit unit 20 for stably smoothing the voltage converted by the converter 10, In parallel with the plurality of transistors Q5, Q6, Q7, Q8, Q9, Q10 and the plurality of transistors to generate a voltage for driving the motor M by using the output voltage of the smoothing circuit unit 20 as an input. A reference voltage connected between the motor driver 40 including the plurality of diodes D5, D6, D7, D8, D9, and D10, the smoothing circuit part 20, and the motor driver 40. Vref) and the voltage flowing through the system to compare the result to the microcomputer (60). The converter 10 and the motor driving unit receive a signal output from the voltage sensing unit 30 for outputting, the sensor 50 for detecting the speed and position of the voltage sensing unit 30 and the motor (M). And a microcomputer 60 for outputting a signal for controlling 40.

Operation by the braking control circuit of the washing machine configured as described above is as follows.

When the commercial power (AC) is externally input to the converter 10, the converter 10 converts the commercial (AC) power input from the outside into a direct current (DC) voltage, the converted DC voltage is smoothed circuit unit 20 Stabilized in. After that, the stable DC voltage is applied to the motor driving unit 30, and the motor driving unit 40 is controlled by the microcomputer 50 to change the DC voltage applied from the smoothing circuit unit 20 to a driving voltage for driving the motor. The motor M is driven by the drive voltage.

When dehydration begins, the current in the system flows from the smoothing circuit to the motor (indicated by I- in the figure). As described in the related art, when the door of the washing machine is opened during dehydration or an unbalancing of the washing tank is detected, the dehydration stroke is stopped and the motor M is suddenly stopped. The voltage induced at (M) is transferred to the smoothing circuit section 20 and charged to the capacitor constituting the smoothing circuit section 20, thereby increasing the capacitor voltage. At this time, the current flows from the motor M side to the smoothing circuit section 20 (indicated by I + in the figure). Thus, the voltage of the capacitor in the smoothing circuit part 20 becomes high.

The voltage sensing unit compares the reference voltage (Vref) set in the system with the voltage of the system (DC link) and applies the result to the microcomputer 60, and in the microcomputer 60 from the voltage sensing unit 30 When it is determined that the detected voltage of the system (Link) is greater than the reference voltage (Vref), the control signal is input to the base terminal of the plurality of transistors constituting the converter unit 10.

The method of controlling the converter 10 by the microcomputer 60 under the above conditions will be described in detail with reference to FIGS. 3 and 4 as follows.

First, the converter unit 10 includes four transistors Q1, Q2, Q3, and Q4 and four diodes D1, D2, D3, and D4 connected in parallel to the transistors, respectively. When a detection signal indicating that an overvoltage flows from the input to the microcomputer 60 is input to the microcomputer 60, the microcomputer 60 outputs a control signal as shown in FIG. 4 and inputs the control signal to the base of each transistor to the converter 10. Will be controlled.

By the control signal input from the microcomputer 60, the transistors Q1 and Q2 and Q3 and Q4 of the converter 10 are operated to complement each other. In addition, transistors Q1 and Q4 and Q2 and Q3 are controlled to operate simultaneously.

When the voltage sensing unit 30 detects that an overvoltage is applied to the system (DC link terminal), the transistors constituting the converter 10 are selectively turned on / off by receiving a control signal of the microcomputer 60. The overvoltage can be flowed to the commercial power supply.

In addition, when the voltage of the system (DC link stage) detected by the voltage sensing unit 30 is less than the reference voltage (Vref), by turning off all the transistors constituting the converter 10 by flowing the voltage of the system toward the commercial power source It prevents and serves to convert the commercial power supplied from the outside into direct current (DC) voltage.

The braking control circuit of the washing machine according to the present invention configured as described above does not use a braking resistor to release the overvoltage flowing in a conventional system, and configures a converter that receives a commercial (AC) power and converts it into a direct current (DC) voltage. Unlike the conventional rectifier diodes, transistors are connected to the plurality of diodes in parallel, and the bases of the transistors are controlled by signals generated by the microcomputer 60 to control the braking system (DC link stage). When the voltage flowing in the system exceeds a certain voltage, the transistors can be selectively turned on / off to pass the overvoltage flowing in the system toward the commercial power supply, thereby preventing the system from flowing a certain voltage or more. Not only simplify the circuit configuration, but also use large-capacity washing machines It is possible. In addition, it can contribute greatly to lowering the cost of the product.

Claims (3)

A converter for converting power supplied from the outside into power required by the system and switching in accordance with a control signal; A smoothing circuit unit for smoothly smoothing the voltage converted by the converter; A motor driver for generating a voltage for driving the motor by inputting an output voltage of the smoothing circuit part; A voltage sensing unit positioned between the motor driving unit and the smoothing circuit unit to sense a voltage of a system; Sensors to detect the position and speed of the motor; and And a microcomputer configured to receive a signal from the voltage sensing unit and the sensor and output a signal for controlling the converter and the motor driving unit. The brake control circuit of claim 1, wherein the converter comprises a plurality of transistors and a plurality of diodes connected in parallel to the plurality of transistors, respectively. The control apparatus of claim 2, wherein the converter receives the control signal of the micom to allow the overvoltage of the system to flow toward an external power source of the system when the detected voltage value input from the voltage sensing unit is a voltage higher than a reference value set by the system. A brake control circuit for a washing machine, which selectively turns on / off transistors constituting the converter.