KR100878471B1 - PCB safety device of washing machine - Google Patents

Abstract

[0001] The present invention relates to a PCB safety device for a washing machine, and more particularly, to a PCB safety device for a washing machine, and more particularly to a PCB safety device for a washing machine which prevents overheating due to PCB leakage The present invention relates to a PCB safety device for a washing machine.

The present invention relates to a washing machine having a plurality of sensors associated with a washing cycle and a PCB to which sensing data of the sensor is input, the washing machine comprising: an overcurrent flowing from the sensor to an input port of the PCB when an overcurrent is generated by tracking by at least one sensor; And an overcurrent shutoff unit for shutting off the overcurrent shutoff unit.

Description

[0001] The present invention relates to a safety device for a washing machine,

FIG. 1A is a schematic block diagram of a conventional washing machine control system,

1B is a circuit diagram of a motor driving unit of a conventional washing machine control system,

FIG. 2 is a circuit diagram of a PC security device of a washing machine according to an embodiment of the present invention,

FIG. 3 is a detailed circuit diagram of a PC security device of a washing machine according to an embodiment of the present invention,

4A and 4B are graphs of overcurrent data for the concentration of the washing water according to the embodiment of the present invention.

Description of the Related Art [0002]

1: PCB power section 2: PCB microcomputer

10: voltage regulator 20: voltage IC

100: sensor unit R1, R11, R12, R13, R14: resistance

C1 to C5: Capacitor TF: Transformer

SW: Poly switch F: Fuse

D1 to D2: Diode BD: Bridge diode

[0001] The present invention relates to a PCB safety device for a washing machine, and more particularly, to a PCB safety device for a washing machine, and more particularly to a PCB safety device for a washing machine which prevents overheating due to PCB leakage The present invention relates to a PCB safety device for a washing machine.

Generally, a washing machine is largely composed of a washing machine for washing and dewatering laundry, a motor for providing a rotational driving force to the washing machine, and a printed circuit board (PCB) for controlling the motor.

1A and 1B show a motor control system of a conventional inverter washing machine. FIG. 1A is a schematic block configuration diagram of an overall system, and FIG. 1B is a circuit configuration diagram of a motor driving section (inverter).

That is, the motor control system of the conventional inverter washing machine includes a rectifying part 102 that receives an AC power source 101 from the outside to convert it into a DC current and outputs the DC current, and a rectifying part 102 that removes AC components mixed in the DC voltage through the rectifying part 102 A motor drive unit 104 for converting the DC voltage through the capacitor 103 to a three-phase alternating current and supplying the DC voltage to the motor 105, and a shunt resistor for current flowing in the system. A sensor (Hall sensor) 108 for detecting the position of the rotor of the motor 105, and a current detector 107 for detecting the position of the rotor of the motor 105 from the current protector 107 and the sensor 108 A microcomputer 109 for controlling all the logic related to ON / OFF of the switching elements S1 to S6 in the motor driving section for controlling the operation of the motor 105 based on the signal ). In FIG. 2, reference characters Q1 to Q6 denote transistors and D1 to D6 denote diodes D1 to D6, respectively. The operation of such a washing machine is as follows.

First, when an external AC power source (for example, AC 220 V, 60 Hz) 101 is supplied to the washing machine, the rectifying unit 102 converts the inputted AC voltage into a DC voltage and outputs it. Then, the motor driving unit 104 converts the DC voltage to a three-phase (U, V, W) AC voltage and supplies it to the motor 105. Here, the operation of the motor driving unit 104 is performed according to a control command of the microcomputer 109 as well. Accordingly, the switching elements S1 to S6 are turned on / off according to the control command to supply the three-phase AC voltage to the motor 105. [

As described above, when the three-phase AC voltage is supplied from the motor driving unit 104 to the motor 105, the motor 105 rotates, thereby performing washing and dewatering processes.

On the other hand, when an abnormal current flows to the DC link end due to a severe fluctuation of the AC power supply 101 supplied from the outside during normal operation of the washing machine, the current protector 107 detects the current flowing through the shunt resistor 106, And transmits it to the computer 109.

Then, the microcomputer 109 compares the detected current with the set reference current value, and turns off the driving signal of the motor driving section 104 when the detected current value is equal to or larger than the reference current value. As a result, the operation of the motor driving unit 104 is stopped, thereby protecting the motor driving unit 104.

However, there is a separate safety device for preventing damage to the internal system of the washing machine when the overcurrent occurs due to the influence of tracking of the DC sensor stage and the AC stage due to leakage of the washing machine.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the prior art as described above, and it is an object of the present invention to provide an overcurrent detecting apparatus, To provide a PCB safety device for a washing machine capable of preventing PCB components from being burned and thereby preventing a fire PL.

In order to achieve the above object, a technical means according to the present invention is a washing machine having a plurality of sensors associated with a washing cycle and a PCB to which sensing data of the sensor is input, And an overcurrent blocking unit for blocking an overcurrent flowing from the sensor to an input port of the PCB.

DC power is used and the earth is close to the sensor. In case leakage occurs due to leakage, the overcurrent is prevented from flowing into the sensor and PCB in case of tracking due to insulation breakdown. It is possible to secure from damage and fire PL.

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

FIG. 2 is a block diagram of a PCB of a washing machine according to an embodiment of the present invention, and FIG. 3 is a detailed block diagram of a PCB safety device.

A PCB (Printed Circuit Board) is composed of a power supply unit 1 for supplying driving power to each component of the washing machine and a microcomputer 2 for controlling the washing cycle of the washing machine. More specifically, a relay RY for turning on or off the power of the washing machine, a bridge diode BD for converting AC power inputted from the outside into AC power and outputting the DC power when the AC power is inputted from the outside, and a bridge diode BD Capacitors C1 and C2 for smoothing the DC power by removing pulsation mixed in the DC power supplied through the capacitors C1 and C2 and a transformer TF for converting the smoothed DC power outputted from the capacitors C1 and C2 using electromagnetic induction phenomenon, Diodes D1 and D2 for rectifying the converted current or converted voltage outputted from the transformer; capacitors C3 and C4 connected to the diodes D1 and D2 for removing noise components of the rectified voltage; Capacity A voltage regulator 10 connected to the capacitor C3 and converting the input DC voltage into a predetermined DC voltage and outputting the DC voltage and outputting the converted DC voltage; 20, a resistor R1 connected to the voltage regulator 10, and a capacitor C5.

The microcomputer 2 of the PCB compares various data inputted from the sensor unit 100 with preset reference data and controls a display unit (not shown) when the sensing data of each sensor is out of a predetermined range of reference data And controls to display an error of the corresponding sensor.

The sensor unit 100 includes a first temperature sensor 110 for sensing the temperature of water, a second temperature sensor 120 for sensing the temperature of the heater, a door opening / closing sensor 130 for sensing the opening / closing of the door, A water level sensor 140 for sensing the height of the washing water, a pressure sensor (not shown) for sensing the weight of the laundry, and a Hall sensor (not shown) for sensing the rotor position of the motor.

The plurality of sensors constituting the sensor unit 100 receive DC driving power from the PCB and drive the sensed data to the microcomputer 2 of the PCB.

The overcurrent blocking part is mounted between the PCB and the sensor part. When the washing machine is driven, leakage may occur in the washing machine. Multiple sensors using DC power supply are close to the ground, , The overcurrent is prevented from flowing into the PCB from the multiple sensors in advance to prevent damage to the PCB components due to the overcurrent and to secure the safety from the fire PL.

Here, the overcurrent shut-off unit is installed inside the PCB, and is connected between each sensor and the PCB, and when the over current is generated due to leakage, a poly switch (SW) or a fuse (not shown) It is preferable to use one.

In this case, the fuse blows when the overcurrent flows, and the fuse is blown to protect the converter, thereby preventing the PCB from being damaged.

In addition, although a fuse is used for the overcurrent protection PCB, there is an inconvenience of replacing the fuse once it is disconnected by an overcurrent, and the fuse may be disconnected due to the surge voltage. Therefore, it is more preferable to use a poly switch Do.

The poly switch is an electronic fuse that protects the fuse's disadvantages. The operation principle is composed of a special polymer and a conductive material. When an overcurrent flows into the PCB, the poly switch is generally turned on It acts like a fuse that opens the PCB by changing from a very low low resistance (0 to 5 ohms) to a high resistance.

In addition, when the cause of the overcurrent is removed, the polis position becomes low resistance state and can be reused.

When the overcurrent flows along the ground surface of the PCB and the sensor, the PCB and the sensor are partially decomposed due to the ripple heat, and a carbonaceous conductive path is generated in which a minute flame is generated, thereby preventing the erosion tracking.

The overcurrent blocking unit is installed inside the PCB, and is a low capacity resistor (R11 to R14) connected between the plurality of sensors and the PCB, and blocks the overcurrent flowing from the plurality of sensors to the plurality of input ports of the PCB.

Here, the poly switch SW and the low-capacity resistors R11 to R14 can be mounted together inside the PCB, and can be mounted separately.

As shown in FIGS. 4A to 4C, the amount of water leaking during washing machine operation is an overcurrent waveform according to detergent concentration due to detergent water.

That is, FIG. 4A shows that the maximum current is 12 A with a detergent concentration of 10%, FIG. 4B shows a maximum current of 24 A with the detergent concentration of 20% concentration, FIG. 4C shows the maximum current of 32 A with a detergent concentration of 30% , The overcurrent increases because the amount of the electrolyte increases as the detergent concentration increases.

Accordingly, it is preferable to operate at least one of the poly switch SW and the resistors R11 to R14 according to the magnitude of the overcurrent flowing when the overcurrent due to the leakage is applied.

Also, the overcurrent blocking unit is installed outside the PCB, and is a fuse (F) connected between the plurality of sensors and the PCB, thereby blocking the overcurrent flowing into the plurality of input ports of the PCB from the plurality of sensors.

In addition, it is preferable that the ground which is commonly drawn out to the outside of the ground of the PCB and the sensor is drawn out through the fuse F.

Here, the fuse F may be mounted together with the low capacity resistors R11 to R14 and the poly switch SW, or may be separately provided.

That is, the fuse F, the low-capacity resistors R11 to R14, and the poly-switch SW are preferably mounted between the PCB and at least one of the PCBs.

Accordingly, the sensor using the DC power source is in close proximity to the ground, so that the insulation breakdown due to leakage occurs when the leakage occurs, and the overcurrent can be prevented from flowing into the plurality of sensors and the PCB when the tracking is caused by the insulation breakdown.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

As described in detail above, according to the present invention, insulation breakdown due to water leakage occurs when leakage occurs due to the proximity of a sensor using a DC power source, and when overloading occurs due to insulation breakdown, It is possible to prevent the damage of the PCB parts due to the overcurrent and to secure the safety from the fire PL.

Claims (7)

1. A washing machine comprising a plurality of sensors associated with a washing cycle and a PCB to which sensing data of the sensor is inputted, An overcurrent shutoff unit for shutting off an overcurrent flowing from the sensor to an input port of the PCB when an overcurrent is generated by tracking by at least one sensor; And a low-capacitance resistor connected between the input port of the PCB and the sensor connected to the input port, for blocking an overcurrent flowing into the PCB. 2. The overcurrent shut-off device according to claim 1, Wherein the PCB is one of a poly switch or a fuse mounted inside the PCB and interposed between the PCB and a plurality of sensors to block an overcurrent flowing into the PCB. delete The method according to claim 1, Further comprising a fuse mounted on the outside of the PCB and interposed between the input port of the PCB and a plurality of sensors to shut off an overcurrent flowing into the PCB when an overcurrent is generated. The method according to claim 1, Wherein the plurality of sensors and the ground that is commonly drawn out of the PCB are grounded through one of a poly switch and a fuse. The apparatus of claim 1, wherein the plurality of sensors A second temperature sensor for sensing the temperature of the heater, a pressure sensor for sensing the weight of the laundry, a water level sensor for sensing the height of the wash water, A door open / close detection sensor, and a hall sensor for detecting a rotor position of the motor. The method according to claim 1, Further comprising a display unit for displaying an abnormality of the sensor in accordance with the control of the PCB if at least one of the sensing data of the plurality of sensors input to the PCB is not within the preset reference data range Safety device of washing machine.

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