KR200252661Y1 - Circuit for protecting over current in bldc motor - Google Patents

Abstract

The present invention relates to an overcurrent protection circuit of the BCD motor, the power supply for providing an AC voltage which is a commercial power supply; A filter circuit for filtering a specific voltage of the AC voltage provided from the power supply unit; A bridge rectifier for bridge rectifying the alternating voltage filtered by the filter circuit; A buffer circuit for removing noise of the AC voltage rectified by the bridge rectifier; A power supply unit receiving the AC voltage rectified by the bridge rectifier to supply a motor driving voltage for driving the BLDC motor; A transformer for converting an AC voltage and a motor driving voltage from which noise is provided by the buffer circuit and the power supply unit into DC voltages; A rectifier for rectifying the AC voltage remaining in the DC voltage converted by the transformer; A BLDC motor operating according to the motor driving DC voltage rectified by the rectifier and the turn-on state of the transistor by the driving signal of the microcomputer; When overcurrent is supplied from the motor-driven DC voltage rectified by the rectifier, an overcurrent protection circuit that turns off the state of the transistor controlling the operation of the BLDC motor to stop the operation of the BLDC motor is prevented from overcurrent. Equipped. Therefore, it is possible to protect the BLDC motor, and also to prevent the phenomenon in which the voltage corresponding to the overcurrent is not applied to the microcomputer A and is destroyed.

Description

CIRCUIT FOR PROTECTING OVER CURRENT IN BLDC MOTOR}

The present invention relates to an overcurrent protection circuit of a brushless direct current (hereinafter abbreviated as BLDC) motor. In particular, in the operation of a refrigerator BLDC FAN motor, a microcomputer and a BLDC motor circuit for driving a BLDC motor through an overcurrent flow A circuit is provided to prevent breakage.

In general, a refrigerator is a generalized product that allows food to be kept fresh in a low temperature state by repeatedly performing a refrigeration cycle of compressing, condensing, expanding, and evaporating a refrigerant.

Among them, a compressor that compresses the refrigerant and increases the pressure thereof is a device used in a refrigerator or an air conditioner, and is a device that compresses the refrigerant by using the rotational force of the BLDC motor.

As such, the schematic structure of the BLDC motor and its driving circuit used in the compressor is shown in FIG.

Referring to FIG. 1, a driving circuit of a conventional BLDC motor includes a power supply unit 1 for providing an AC voltage as a commercial power supply, and a filter circuit 2 for filtering a specific voltage of the AC voltage provided from the power supply unit 1. ), A bridge rectifier 3 for bridge rectifying the AC voltage filtered by the filter circuit 2, and a surge voltage rectified by the bridge rectifier 3 and generated when the switching transistor s is turned off. A transformer for converting an AC voltage from which noise is provided by the buffer circuit 4 to be removed, the power supply unit 5 for supplying the microcomputer voltage, and the buffer circuit 4 and the power supply unit 5 to a DC voltage ( 6), the rectifier 7 for rectifying the AC voltage remaining in the DC voltage converted by the transformer 6, the motor-driven DC voltage rectified by the rectifier 7 and the drive signal of the microcomputer A. By turning on the transistor 9, It includes a BLDC motor 8 is, the BLDC motor as a drive (8) to which the compressor is driven by the rotor rotation of the BLDC motor 8.

That is, the counter electromotive force is output to the windings as the motor rotor rotates. When an excessively high voltage or current is applied to the BLDC motor, the microcomputer A and the BLDC motor circuit for driving the BLDC motor are destroyed.

Therefore, the present invention has been devised to solve the above-described drawbacks, and its purpose is to turn on the operation of the BLDC motor by using an overcurrent protection circuit when abnormal motor driving current is detected due to the overload and component destruction of the BLDC motor circuit. The present invention provides an overcurrent protection circuit of a BLDC motor to turn off / off a state of a transistor to control the motor circuit and the microcomputer configuration circuit.

In the present invention for achieving the above object, the overcurrent protection circuit of the BLDC motor is a power supply for providing an AC voltage which is a commercial power source; A filter circuit for filtering a specific voltage of the AC voltage provided from the power supply unit; A bridge rectifier for bridge rectifying the alternating voltage filtered by the filter circuit; A buffer circuit for removing noise of the AC voltage rectified by the bridge rectifier; A power supply unit receiving the AC voltage rectified by the bridge rectifier to supply a motor driving voltage for driving the BLDC motor; A transformer for converting an AC voltage and a motor driving voltage from which noise is provided by the buffer circuit and the power supply unit into DC voltages; A rectifier for rectifying the AC voltage remaining in the DC voltage converted by the transformer; A BLDC motor operating according to the motor driving DC voltage rectified by the rectifier and the turn-on state of the transistor by the driving signal of the microcomputer; When overcurrent is supplied from the motor-driven DC voltage rectified by the rectifier, an overcurrent protection circuit that turns off the state of the transistor controlling the operation of the BLDC motor to stop the operation of the BLDC motor is prevented from overcurrent. It is characterized by including.

1 is a diagram of a driving circuit of a conventional BC motor,

2 is a detailed view of the overcurrent protection circuit of the BCD motor according to the present invention.

<Description of the symbols for the main parts of the drawings>

10: power supply unit 20: filter circuit

30: bridge rectifier 40: buffer circuit

50: power supply 60: transformer

70: rectifier 80: overcurrent protection circuit

90: motor 81, 83, 100: transistor

A: Micom

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

Referring to FIG. 2, a detailed diagram of an overcurrent protection circuit of a BLDC motor according to the present invention includes a power supply unit 10, a filter circuit 20, a bridge rectifier 30, and a buffer circuit 40. ), A power supply unit 50, a transformer 60, a rectifier 70, an overcurrent protection circuit 80, a BLDC motor 90, and a transistor 100.

The power supply unit 10 provides an AC voltage, which is a commercial power supply (for example, 230V), to the filter circuit 20 when driving a BLDC motor.

The filter circuit 20 is driven by the inductances L3 and L4 and the capacitor C6 and filters the specific voltage of the AC voltage provided from the power supply unit 10 to provide it to the bridge rectifier 30.

The bridge rectifier 30 bridges the AC voltage filtered by the filter circuit 20 and provides the bridge rectifier to the buffer circuit 40 and the power supply 50.

The buffer circuit 40 is a snubber circuit and removes noise of a surge voltage generated when the switching transistor TR (s) in the power supply unit 50 is turned off and provides it to the transformer 60. do.

The power supply unit 50 receives the AC voltage rectified by the bridge rectifier 30 and supplies the motor driving voltage to the transformer 60 to drive the BLDC motor.

The transformer 60 converts the AC voltage and the motor driving voltage from which the noise provided by the buffer circuit 40 and the power supply unit 50 are removed to a DC voltage to provide the rectifier 70.

The rectifier 70 is a circuit composed of a diode, and overcurrent is generated at the rectified DC voltage while providing the BLDC motor 90 with a motor driving DC voltage rectified from the DC voltage remaining in the DC voltage converted by the transformer 60. If provided, the overcurrent is applied to the overcurrent protection circuit 80.

The BLDC motor 90 operates by turning on the transistor 100 by the motor driving DC voltage rectified by the rectifier 70 and the driving signal of the microcomputer A. On the other hand, the BLDC motor 90 stops operating as the transistor 100 is turned off by the motor driving DC voltage rectified by the rectifier 70 and the driving signal of the overcurrent protection circuit 80.

The overcurrent protection circuit 80 is a circuit for stopping the operation of the BLDC motor 90 according to the overcurrent when the overcurrent is provided by the motor driving DC voltage rectified by the rectifier 70, and provided by the rectifier 70. The state is changed by the resistors R5 and R6 for distributing the voltage corresponding to the overcurrent, the capacitor C3 for charging the voltage divided by the resistors R5 and R6, and the voltage charged in the capacitor C3. A transistor 81 to be turned on, a capacitor C4 for charging a voltage applied according to the turn-on state of the transistor 81, resistors R7 and R8 for distributing a voltage charged in the capacitor C4, and a resistor; With the transistor 83 whose state is turned on by the voltage divided by R7 and R8, the state of the transistor 100 controlling the operation of the BLDC motor 90 is turned off. The operation of the BLDC motor 90 is stopped.

Based on the above configuration, the operation of the overcurrent protection circuit of the BLDC motor according to the present invention will be described in more detail.

First, when driving a BLDC motor, when a user inserts the power supply unit 10 into an outlet (not shown), the AC voltage, which is a commercial power supply (eg, 230 V) in the power supply unit 10, is a filter circuit ( 20, the filter circuit 20 filters the specific voltage of the AC voltage provided from the power supply unit 10 and provides it to the bridge rectifier 30.

Then, the bridge rectifier 30 rectifies the AC voltage filtered by the filter circuit 20 and provides the buffer circuit 40 and the power supply unit 50, respectively.

The buffer circuit 40 removes noise of the AC voltage rectified by the bridge rectifier 30 and provides the transformer 60 to the transformer 60, and the power supply unit 50 receives the AC voltage rectified by the bridge rectifier 30. The motor driving voltage for driving the BLDC motor is supplied to the transformer 60.

The transformer 60 converts the AC voltage and the motor driving voltage from which the noise provided by the buffer circuit 40 and the power supply unit 50 are removed to a DC voltage to provide the rectifier 70.

The rectifier 70 provides the BLDC motor 90 with a motor driving DC voltage obtained by rectifying the AC component remaining in the DC voltage converted by the transformer 60. At the same time, the microcomputer A provides a driving signal to the transistor 100 through the voltage distribution resistors R3 and R4 so that the transistor 100 is turned on.

As a result, the BLDC motor 90 receives the motor driving DC voltage from the rectifier 70 and the compressor is driven by the rotation of the rotor of the BLDC motor 90 as the transistor 100 is turned on.

As described above, when an overcurrent is provided at the DC voltage rectified by the rectifier 70 during the normal operation of the BLDC motor 90, the microcomputer driving the BLDC motor 90 according to the overcurrent described above ( A) and the overcurrent protection circuit 80 is applied to prevent the BLDC motor 90 circuit from being destroyed.

That is, when a voltage corresponding to the overcurrent provided from the rectifier 70 is provided to the resistors R5 and R6 and the capacitor C3, the voltage is divided by the resistors R5 and R6, and this divided voltage is the capacitor. (C3) is charged.

In this way, the state of the transistor 81 is turned on by the voltage charged in the capacitor C3, and the voltage is charged in the capacitor C4 according to the turn-on state of the transistor 81, and the charged voltage is a resistor ( The voltage is divided by R7 and R8, and the divided voltage turns off the state of the transistor 100 that controls the operation of the BLDC motor 90 as the state of the transistor 83 is turned on. (turn off) to stop the rotor operation of the BLDC motor 90.

Accordingly, the BLDC motor 90 can be protected, and the phenomenon in which the voltage corresponding to the overcurrent is not applied to the microcomputer A can be prevented from being destroyed.

Therefore, the present invention protects the BLDC motor by turning off the state of the transistor controlling the operation of the BLDC motor by using the overcurrent protection circuit when an abnormal motor driving current is detected due to the overcurrent of the BLDC motor circuit. In addition, the microcomputer A may also be prevented from being destroyed due to the voltage corresponding to the overcurrent not being applied.

Claims (2)

In a driving circuit for driving a BLC motor (hereinafter, abbreviated as BLDC) motor, A power supply unit providing an AC voltage which is a commercial power supply; A filter circuit for filtering a specific voltage of the AC voltage provided from the power supply unit; A bridge rectifier for bridge rectifying the alternating voltage filtered by the filter circuit; A buffer circuit for removing noise of an AC voltage rectified by the bridge rectifier; A power supply unit receiving an AC voltage rectified by the bridge rectifier and supplying a motor driving voltage for driving the BLDC motor; A transformer for converting an AC voltage and a motor driving voltage from which noise is provided by the buffer circuit and a power supply unit into a DC voltage; A rectifier for rectifying the AC voltage remaining in the DC voltage converted by the transformer; A BLDC motor operating according to the motor driving DC voltage rectified by the rectifier and the turn-on state of the transistor by the driving signal of the microcomputer; When overcurrent is provided from the motor driving DC voltage rectified by the rectifier, the operation of the BLDC motor is stopped by turning off the state of a transistor controlling the operation of the BLDC motor to prevent the overcurrent. An overcurrent protection circuit of a BLDC motor comprising an overcurrent protection circuit. The method of claim 1, wherein the overcurrent protection circuit, When the overcurrent is detected in the rectifier, the resistors R5 and R6 for distributing the voltage corresponding to the overcurrent, the capacitor C3 for charging the voltage divided by the resistors R5 and R6, and the capacitor ( The transistor 81 whose state is turned on by the voltage charged in C3), the capacitor C4 which charges the voltage applied according to the turn-on state of the transistor 81, and the capacitor C4 are charged. Resistor R7 and R8 for distributing the received voltage and transistor 83 whose state is turned on by the voltage divided by the resistors R7 and R8 are further included. Motor overcurrent protection circuit.