KR200220816Y1 - Refrigerator Brushless Fan Motor Control Circuit - Google Patents

Abstract

Disclosed is a brushless fan motor control circuit of a refrigerator which suppresses a ripple generated in a current waveform during bypass of a transistor in a brushless fan motor driving circuit to prevent a counter voltage. The brushless fan motor control circuit of the refrigerator includes: a first transistor configured to turn on when an output voltage applied when a hall sensor sensing an electric field senses an N pole of the rotor is input to a base terminal; A second transistor that turns on when an output voltage applied when the hall sensor senses the S pole of the rotor is input to the base terminal; First and second zener diodes connected to the base terminal and the anode terminal of the first and second transistors, and connected to the collector terminal and the cathode terminal, respectively, to apply a constant voltage; The first and second capacitors are provided in parallel contact with the collector terminal and the emitter terminal of the first and second transistors to absorb sparks of the contacts. Therefore, in the driving circuit of the brushless fan motor, it is possible to prevent the counter electromotive voltage generated when the transistor is bypassed.

Description

Refrigerator brushless fan motor control circuit.

The present invention relates to a brushless fan motor control circuit of a refrigerator. In particular, in a brushless fan motor driving circuit, a brushless fan of a refrigerator which prevents a counter electromotive voltage by suppressing a ripple occurring in a current waveform during bypass of a transistor It relates to a motor control circuit.

Referring to FIG. 1, a control circuit of a general fan motor includes a temperature control switch 80 at a power supply (AC) side and a timer 90 connected at a rear end thereof to a compressor circuit (overload protection) at a terminal T4 of the timer. Connect the device 140, the compressor 130, the starter 120 and the fan motor circuit (fan motor 70, the freezing door switch 50, the refrigerator door switch 40), the refrigerator door switch 40 The power supply AC is connected to the internal lamp 60 or the fan motor circuit to be selectively applied. The terminal T2 of the timer 90 has a defrost control switch 150, a defrost heater 100, and a temperature fuse (). The power source AC is applied through the 110.

At this time, the cam and the terminal operating portion of the timer 90 are composed of a cam (not shown) that is rotated by the timer driving motor 91 and terminals T2 to T4 that are in cross contact with each other by the shape of the cam.

Therefore, when the switching terminals T3 and T4 of the timer 90 are at any position in the compressor operating section of the cam, the contacts of the terminals T3 and T4 are brought into contact with each other so that the terminals T3 and T4 of the timer 90 are in contact. Since the state is connected to the on / off of the temperature control switch 80, the compressor 130 driving circuit and the fan motor 70 driving circuit unit is operated.

On the other hand, when the terminal T4 enters the defrost section of the cam, the terminal T3 is separated from the terminal T4 and comes into contact with the contact point of the terminal T2. Thus, in the circuit diagram, the contacts T3 and T2 of the timer 90 Since the power source AC flows from the contact point T3 to the contact point T2 and the defrost control switch 150, the time driving motor 91 stops operation and the defrost heater 100 generates heat to start defrosting.

Then, when the ambient temperature is increased due to the heating of the defrost heater 100 and the set temperature value of the defrost control switch 150 is greater than the defrost control switch 150 is turned off, the timer drive motor 91 operates and the cam rotates accordingly. In this case, the compressor 130 and the fan motor 70 are operated because the terminals T2 to T3 are separated from each other and the terminals T3 to T4 are contacted.

The driving of the conventional fan motor (Cooling FAN) is driven at a constant speed by using an AC power source (AC) by controlling the fan motor in conjunction with the drive of the compressor on / off.

By the way, the driving of the fan motor by such a switch is relatively high in efficiency and suitable for controlling the speed and position, but has a mechanical switch mechanism called a brush and a commutator.

That is, since the brush and the commutator are frictionally contacted at a high speed, the brush is worn and graphite or metal powder is generated, thereby causing an electrical obstacle.

In order to solve this problem, a brushless motor (BLDC) is used. The brushless motor is also referred to as a commutatorless motor, and the brush and the commutator of the DC motor are referred to as transistors or silicon. The motor is replaced with a silicon controlled rectifier (SCR).

As for the brushless fan motor driving circuit of the two-phase driving method (bipolar method), referring to FIG. 2, a rotor sensor (Magenet Rotor) 10 is located at a position as shown in FIG. 20) is close to the magnetic pole of the rotor 10, and at this time is the state receiving the maximum magnetic flux.

The Hall sensor 20 senses the magnet N pole, and the Hall sensor 10 output voltage VH + sends an operation signal to the base terminal of the first transistor 30 side of the power supply to generate a large voltage. The first coil current i1 flows while the first coil 90 is conducting, and the first coil 90 is excited.

When the first coil current i1 flows, an N pole is generated in the first coil 90 according to Fleming's right hand law, and pulls the S pole of the rotor 10.

When the magnet N pole due to rotation moves away from the hall sensor 10, the magnetic flux passing through the hall sensor 10 disappears, and neither of the output voltages VH + and VH- of the hall sensor 10 occurs.

Therefore, the first and second transistors 30 and 40 are turned off at the same time.

However, since the rotation is continued due to the inertia of the rotor 10 even if the excitation of the coil is broken, it moves 180 degrees from the S pole to the N pole position.

At this time, the Hall sensor 20 receives the magnetic flux of the S pole to the maximum, and the second transistor 40 is in a conducting state. As a result, the second coil current i2 flows and the second coil 100 is excited to excite the S pole. Occurs and this pulls the N pole of the rotor 10 to generate a rotational force.

This operation is repeated to continue the rotation operation continuously.

However, when the current flows through the coil of the BLDC motor and the current is suddenly cut off, that is, when the transistor is switched off, the counter electromotive phenomenon occurs in the direction of disturbing the change of the current in the coil, thereby generating a very high voltage.

Accordingly, there is a problem in that a ripple occurs in the current waveform during bypass of the transistor, resulting in a counter voltage.

The present invention was devised to solve the above problems, and in the brushless fan motor driving circuit, a brushless fan motor of a refrigerator which suppresses a ripple occurring in a current waveform during bypass of a transistor to prevent counter voltage. The purpose is to provide a control circuit.

1 is a fan motor control circuit diagram of a conventional refrigerator freezer cold air circulation,

2 is a fan motor control circuit diagram using a conventional BLDC motor;

3 is a circuit diagram of a brushless fan motor control circuit of a refrigerator according to the present invention;

<Description of the code | symbol about the principal part of drawing>

10 ... rotor 20 ... hall sensor

30 ... 1st transistor 40 ... 2nd transistor

50 ... 1st Zener Diode 60 ... 2nd Zener Diode

70 ... first capacitor 80 ... second capacitor

90 ... first coil 100 ... second coil

The brushless fan motor control circuit of the present invention refrigerator that achieves the above object comprises a first transistor for turning on when an output voltage applied when a Hall sensor sensing an electric field is detected at the N pole of the rotor and inputted to a base terminal, and a Hall sensor A brushless fan motor having a second transistor, which is turned on when an output voltage applied when the S pole of the rotor is input to the base terminal; First and second zener diodes connected to the base terminal and the anode terminal of the first and second transistors, and connected to the collector terminal and the cathode terminal, respectively, to apply a constant voltage; The first and second capacitors are provided in parallel contact with the collector terminal and the emitter terminal of the first and second transistors to absorb sparks of the contacts.

According to the feature of the present invention configured as described above, the brushless fan motor control circuit of the refrigerator according to the present invention, in the drive circuit of the brushless fan motor, suppresses the ripple generated in the current waveform when the transistor bypasses the counterweight The voltage can be prevented.

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

Referring to FIG. 3, the brushless fan motor control circuit of the present invention refrigerator turns on when an output voltage applied when the hall sensor 20 that senses an electric field senses an N pole of the rotor 10 is input to a base terminal. A first transistor 30; A second transistor 40 which turns on when an output voltage applied when the hall sensor 20 detects the S pole of the rotor 10 is input to the base terminal; First and second coils 90 and 100 that are excited when the first and second transistors are turned on; First and second zener diodes 50 and 60 connected to the base terminal and the anode terminal of the first and second transistors 30 and 40 and the collector terminal and the cathode terminal respectively to apply a constant voltage; First and second capacitors 70 and 80 are respectively provided in parallel contact with the collector terminals and the emitter terminals of the first and second transistors 30 and 40 to absorb sparks of the contacts.

In more detail, in the brushless fan motor driving circuit of the two-phase driving method (bipolar method), the rotor (Magenet Rotor) 10, which is a rotor, is a Hall sensor at the position as shown in FIG. 20 is the state closest to the magnetic pole of the rotor 10 and at this time is receiving the maximum magnetic flux.

The Hall sensor 20 senses the magnet N pole, and the Hall sensor 10 output voltage VH + sends an operation signal to the base terminal of the first transistor 30 side of the power supply to generate a large voltage. 30, the first coil current i1 flows and the first coil 90 is excited.

When the first coil current i1 flows, an N pole is generated in the first coil 90 according to Fleming's right hand law, and attracts the S pole of the rotor 10.

When the magnet N pole due to rotation moves away from the hall sensor 10, the magnetic flux passing through the hall sensor 10 disappears, and neither of the output voltages VH + and VH- of the hall sensor 10 occurs.

Therefore, the first and second transistors 30 and 40 are turned off at the same time.

However, since the rotation is continued due to the inertia of the rotor 10 even if the excitation of the coil is broken, it moves 180 degrees from the S pole to the N pole position.

At this time, the Hall sensor 20 receives the magnetic flux of the S pole to the maximum, and the second transistor 40 is in a conducting state. As a result, the second coil current i2 flows and the second coil 100 is excited to excite the S pole. Occurs and this pulls the N pole of the rotor 10 to generate a rotational force.

This operation is repeated to continue the rotation operation continuously.

On the other hand, if current flows through the coils 90 and 100 of the brushless fan motor and the current is interrupted, a reverse voltage phenomenon occurs in a direction that prevents the change of the current in the coil, thereby generating a high voltage.

Accordingly, the first and second zener diodes 50 and 60 (Zener diode) connected to the base terminal and the anode terminal of the first and second transistors 30 and 40 and the collector terminal and the cathode terminal are respectively connected to a constant voltage. Is authorized.

Zener breakdown refers to a phenomenon in which when the reverse current of a pn junction is applied with a reverse voltage above a certain value, the zener effect rapidly increases and the operating resistance becomes almost zero. It is called.

In the first and second zener diodes (constant voltage diodes) 50 and 60, a current flows rapidly at an arbitrary value in the reverse direction, and the voltage becomes constant.

Therefore, if a reverse voltage is applied to the first and second zener diodes 50 and 60, the current flows very little before the applied voltage reaches the constant voltage, but when the voltage exceeds the constant voltage, the current flows rapidly and the first and second zener diodes The voltage of (50, 60) becomes constant.

In addition, the first and second capacitors 70 and 80, which are in parallel contact with the collector terminals and the emitter terminals of the first and second transistors 30 and 40, respectively, may temporarily store and release electricity. Therefore, the ripple of the contact can be absorbed.

The brushless fan motor control circuit of the refrigerator according to the present invention, in the drive circuit of the brushless fan motor, by attaching a zener diode and a capacitor to suppress the ripple voltage generated in the current waveform during the bypass of the transistor and to prevent back EMF It becomes possible.

Claims (1)

The first transistor turns on when an output voltage applied when the Hall sensor sensing the electric field senses the N pole of the rotor, and the output voltage applied when the Hall sensor detects the S pole of the rotor is connected to the base terminal. In the brushless fan motor having a second transistor that is turned on when input, First and second zener diodes connected to the base terminal and the anode terminal of the first and second transistors, and connected to the collector terminal and the cathode terminal, respectively, to apply a constant voltage; And a first and a second capacitor in parallel contact with the collector terminal and the emitter terminal of the first and second transistors, respectively, to absorb sparks of the contact.