KR0123429B1 - Cooling fan motor method & circuit of refrigerators - Google Patents

Abstract

The method is to maintain a constant rotational speed of the cooling fan motor for circulating cooling air even when the input voltage of the cooling fan motor changes, and makes the cooling fan motor rotate at high speed in order to rapidly raise the internal temperature of the refrigerator after the initial starting and defrosting steps. The method controls the fan motor by rotating the cooling fan motor at a high speed for rapid cooling operation during the initial starting and defrosting steps, reducing the rotational speed of the fan motor when an overvoltage is detected from the sensed intensity of the input voltage applied to a micro-computer, and raising the rotational speed of the fan motor when the a low voltage is applied to the micro-computer. The revolution number of the fan motor is controlled by varying the capacity of a starting condenser connected to the subline of the fan motor.

Description

Refrigerator fan motor control method and circuit

1 is a cooling fan motor control circuit diagram of a conventional refrigerator.

2 is a cooling fan motor control circuit diagram of a refrigerator according to the present invention.

* Explanation of symbols for main parts of the drawings

10: high voltage detection means 11: first comparator

12,22: Voltage divider circuit 13,23: Noise canceling circuit

20: low voltage detection means 21: second comparator

30: micom 40: switching unit

40a, 40ｂ: First and second inverters 50: Motor control unit

50a, 50ｂ: First and second relay switch 60: Fan motor

70: power supply

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device of a refrigerator. In particular, in the function of an electronic refrigerator, the control of a cooling fan motor that circulates cold air always maintains a constant rotational speed even when an input voltage fluctuates. The present invention relates to a cooling fan motor control method and a circuit of the refrigerator to allow a high speed rotation in order to rapidly increase the temperature inside the refrigerator at the time of return, so that the rotation speed is controlled by changing the capacity of the starting capacitor.

In general, the cooling fan (FAN) installed in the refrigerator serves to circulate the cool air to the inside, the starting capacitor is connected in parallel to the power line of the motor driving the fan and has one contact point under the control of the microcomputer. The relay is operated to drive only one fixed number of revolutions.

That is, the cooling fan motor control circuit of the conventional refrigerator is connected to the relay RY through the inverter INV at the output terminal A of the microcomputer 30 as shown in FIG. 1 and is driven by the relay RY. The relay switch RSW, which is in contact, is connected to the power supply unit 70 and the main line ML of the fan motor 60, and a starting capacitor (B) between the main line ML and the sub line SL of the fan motor 60. C) is configured in parallel connection.

In the conventional fan motor control circuit configured as described above, when the high signal is output from the microcomputer 30 in order to drive the fan motor 60, the relay RV is operated by inverting the low level by the inverter INＶ to operate the relay switch. (RSW) is connected to the on state and supplies a drive current to the fan motor 60 to rotate the cold air as it is rotated, the start capacitor (C) at the start of the fan motor 60, the winding winding operation The fan motor rotates by creating a phase difference between the current and the starting winding current.

In addition, when the microcomputer 30 outputs a low signal in order to stop the driving of the fan motor 60, the inverter INV is inverted to a high level so that the relay RY stops operating and the relay switch RSW is turned on. And the rotation of the fan is stopped by cutting off the current supplied to the fan motor 60.

As described above, the conventional fan motor control circuit is driven by only one fixed rotation speed, and thus, various functions cannot be secured, and the fan motor is operated with the cooling power determined by the product set to reduce the freshness of the product. In addition to increasing the power consumption, the reliability of the refrigerator is to be lowered.

In addition, the torque T that generates the actual torque in a general motor

(Tf is the normal torque, Tb is the reverse torque, Im is the main current and Ia is the sub current.)

In the above equation, the torque T increases in proportion to Im and Ia (the remaining terms are constants determined by the core of the motor and the number of turns).

Ia and Im (the main and sub input currents) become smaller when their respective reactance values become smaller (Ia and Im become larger, and each reactance value becomes smaller as the capacitor capacity increases).

In other words

therefore

Becomes

Therefore, the torque T of the motor changes as the C value of the sub changes.

The present invention has a high and low voltage detecting means for detecting the input voltage of the upper and lower limit lines using this principle, and has two circuits and two contacts after connecting a plurality of starting capacitors having different capacities to the subline of the fan motor. By controlling one or more relays at the microcomputer to selectively change the starting capacitor capacity value of the fan motor, it adjusts the phase difference between the motor winding current and the starting winding current to maintain a constant rotational speed even when the input voltage changes. And a cooling fan motor control method of the refrigerator to maintain a high-speed rotation in order to rapidly lower the temperature inside the refrigerator during initial start-up and return after defrosting, and to be controlled in multiple stages according to the function of the product and the state of the SET. It is an object of the present invention to provide a circuit.

In order to achieve the above object, the present invention provides a cooling fan motor control method of a refrigerator operating under the control of a microcomputer to regulate cold air. Detects the strength of the input voltage applied to the microcomputer and reduces the rotational speed of the fan motor when overvoltage is applied, and detects the strength of the input voltage applied to the microcomputer and increases the speed of the fan motor when the low voltage is applied. The motor is controlled at a constant rotation speed irrespective of the change in the input voltage, and the rotation speed control of the fan motor is made to control by varying the capacity of the starting capacitor connected to the subline of the fan motor.

In addition, the present invention is a cooling fan motor control circuit of a refrigerator for switching the microcomputer to the output side of the microcomputer to circulate the cold air by the control of the microcomputer, connected to the input side of the microcomputer to sense the level of the input voltage than the reference voltage set High voltage detection means for detecting a high voltage, low voltage detection means connected to the input side of the microcomputer to detect a voltage lower than the set reference voltage by detecting the level of the input voltage, and connected in parallel to the sub-line of the fan motor to phase difference A plurality of first to third starting capacitors to be provided and connected between the switching unit and the fan motor to supply a driving current to the fan motor, and to connect the first to third starting capacitors to sublines of the fan motor, The motor control unit comprises first and second relays having two circuits and two contacts.

Hereinafter, described in detail by the accompanying drawings as follows.

2 is a cooling fan motor control circuit diagram of a refrigerator according to the present invention, and high and low voltage detecting means 10 and 20 are connected to two input terminals X1 and X2 of the microcomputer 30, respectively. The first and second relays 50a having two circuits and two contacts, which are the motor control unit 50, through the first and second inverters 40a and 40b which are the switching units 40. ) 50b.

In addition, one end of the first to third starting capacitors Ca-Cc is connected in parallel to the subline SL of the fan motor 60, and the other end of the first to third starting capacitors Ca-Cc is connected to each other. It is connected to each contact of the 2nd relay switch 50b.

The high and low voltage detection means (10, 20) includes a stabilization circuit (14) for rectifying and smoothing the output of the transformer (TS), and a voltage dividing circuit (12) for dividing the output voltage of the stabilization circuit (14) ( 22 and the first and second comparators 11 and 21 for generating a signal having a predetermined level by comparing the outputs of the voltage dividing circuits 12 and 22 with a reference voltage, and turning on the outputs according to the output level of the comparator. Transistors Q1 and Q2 for determining a state and transmitting a signal according to an input voltage state to the microcomputer 30, and a noise removing circuit 13 for reducing noise included in an output signal of the transistors Q1 and Q2. (23) is configured.

In addition, the connection configuration relationship between the first and second relays 50a and 50b of the motor control unit 50 and the fan motor 60 may include a power supply unit at a common contact C1 and C2 of the first relay 50a. The common contact C2 of the second relay 50b is connected to the main line ML of the fan motor 60 and the normal close contact NC1 and NC1 'of the first relay 50a. And the normal open contact NO2 and the first starting capacitor Ca are respectively connected.

Then, the normal open contact NO1 (NO1 ') of the first relay 50a is connected to each other and connected to the normal open contact NO2' of the second relay 50b, and the second relay 50b ' The second and third starting capacitors Cb and Cc are connected to the normal open contact NO2 'and the normal close contact NC2', respectively.

According to the second embodiment of the present invention, the motor generated as a signal generated at the output terminals A and B of the microcomputer 30 according to the condition and function of the input voltage by the high and low voltage detection means 10 and 20 according to FIG. The driving of the first and second relays 50a and 50b of the control unit 50 is determined, and the first to third starting capacitors Ca-Cc connected to the subline SL of the fan motor 60 are selected. The control process for each step will be described in a state in which the capacity sizes of the first to third starting capacitors Ca-Cc are assumed to be CaCbCc order.

First, as shown in FIG. 2, the secondary voltage induced by the primary input voltage of the transformer TS is rectified and smoothed through the stabilization circuit 14 of the diode D and the capacitor C1. It is applied to the voltage divider circuits 12 and 22 of the means 10 and the low voltage detection means 20 and transmitted to the first and second comparators 11 and 21.

At this time, the first comparator 11 is supplied with a voltage at a time when the noise of the fan motor 60 is drastically increased as a reference voltage, and the second comparator 21 is a time when the rotational force of the fan motor 60 is rapidly decreased. Is applied as a reference voltage, and the voltage applied from the voltage dividing circuits 12 and 22 is compared with each other to output a high or low signal according to the level of the input voltage.

Accordingly, the transistors Q1 and Q2 are determined to be turned on or off according to the outputs of the first and second comparators 11 and 21, and their output is passed through the noise canceling circuits 13 and 23. By being transmitted to the microcomputer 30, the microcomputer 30 recognizes signals output from the high voltage detecting means 10 and the low voltage detecting means 20 to control the rotation speed of the fan motor 60.

That is, the high and low voltage detection means 10 and 20 transmit a low signal to the microcomputer 30 in a normal state, and an input voltage is applied such that an overvoltage of the fan motor 60 shows a sharp increase in noise. In this case, the output of the high voltage detecting means 10 is inverted to a high level so that the microcomputer 30 recognizes that the current input voltage is in a high voltage state.

Therefore, the microcomputer 30 outputs a high signal through the terminal A in order to reduce the rotation speed of the fan motor 60, and the signal thereof is inverted to the low level via the first inverter 40a of the switching unit 40. By driving the first relay 50a of the motor controller 50, the first relay switch SW1 (SW1 ') is connected to the normal open contact NO1 (NO1').

Therefore, the first relay switch SW1 (SW1 ') is connected to the main line ML of the fan motor 60 so that the driving power is supplied and the sub relay of the fan motor 60 is connected through the second relay switch SW2'. The third starting capacitor Cc having the smallest capacity is connected to the line SL to rotate the fan motor 60 at a low speed to prevent overspeed rotation of the fan motor 60 due to the overvoltage supply.

In addition, a high signal is output from the B output terminal of the microcomputer 30 at the initial startup or in the return state after defrosting regardless of the output signals of the high and low voltage detection means 10 and 20, and thus, the fan motor 60 as described above. By increasing the rotational force of the refrigerator to increase the temperature inside the refrigerator to increase the cooling efficiency.

On the other hand, the high and low voltage detection means 10 and 20 transmits a high signal to the microcomputer 30 in a normal state, and a low voltage such that the input voltage is such that the fan motor 60 is unable to perform a cooling function due to the low rotational force. When applied, the output of the low voltage detecting means 20 is inverted to a low level so that the microcomputer 30 recognizes that the current input voltage is in a low voltage state.

Therefore, the microcomputer 30 outputs a high signal through the B terminal to increase the rotation speed of the fan motor 60, and the signal thereof is inverted to the low level via the second inverter 40b of the switch unit 40. By driving the second relay 50b of the motor control unit 50, the second relay switch SW2 (SW2 ') is connected to the normal open contact NO2 (NO2').

Therefore, the driving power is supplied to the main line ML of the fan motor 60 through the first and second relay switches SW1, SW1 ', and SW2, and at the same time, the fan motors are connected through the second relay switch SW2. The first starting capacitor Ca having the largest capacity is connected to the subline SL of 60 to prevent the fan motor 60 and the cooling capacity from being lowered due to the low voltage supply by rotating the fan motor 60 at high speed. .

As described above, the present invention includes a high and low voltage detection means for detecting input voltages of the upper and lower limits, and connects two starters with two circuits having different capacities having different capacities to the subline of the fan motor. By controlling one or more relays in the microcomputer to selectively change the starting capacitor capacity value of the fan motor, by adjusting the phase difference between the motor winding current and the starting winding current, the constant rotation speed is always maintained even when the input voltage changes. It is possible to increase the cooling efficiency by controlling a number of stages in accordance with the function of the product and the state of the set (SET) in order to maintain a high speed, so as to quickly lower the temperature inside the refrigerator during initial startup and recovery after defrosting.

Claims (5)

In the method of controlling a cooling fan motor of a refrigerator operated by a microcomputer to control cold air, the fan motor is rotated at a high speed during initial startup and defrosting to cool rapidly and senses the intensity of the input voltage applied to the microcomputer. When the over voltage is applied, the rotation speed of the fan motor is reduced, and the intensity of the input voltage applied to the microcomputer is sensed, and when the low voltage is applied, the rotation speed of the fan motor is increased to rotate the fan motor regardless of the change of the input voltage. And controlling the number of revolutions of the fan motor by varying the capacity of the starting capacitor connected to the subline of the fan motor. In the cooling fan motor control circuit of the refrigerator that is connected to the output side of the microcomputer to circulate the cold air by the control of the microcomputer, connected to the input side of the microcomputer 30 senses the level of the input voltage than the set reference voltage High voltage detecting means (10) for detecting a high voltage, low voltage detecting means (20) connected to an input side of the microcomputer (30) for detecting a level of an input voltage and detecting a voltage lower than a set reference voltage; A plurality of first to third starting capacitors Ca-Cc connected in parallel to the subline SL of the fan motor 60 to provide a phase difference, and between the switching unit 40 and the fan motor 60. Cooling the refrigerator provided with a motor control unit 50 connected to supply a drive current to the fan motor, and selectively connects the first to third starting capacitors Ca-Cc to the subline SL of the fan motor. Fan motor control circuit. 3. The cooling fan motor control circuit according to claim 2, wherein the capacitance values of the first to third starting capacitors (Ca-Cc) are set differently. 3. The control circuit according to claim 2, wherein the motor controller (50) comprises first and second relays (50a) and (50b) having two circuits and two contacts. The method of claim 3, wherein the common contact (C1) (C2) of the first relay (50a) is connected to the power supply and the main line (ML) of the fan motor 60, the normal closing of the first relay (50a) The common contact C2 of the second relay 50b, the normal open contact NO2, and the first starting capacitor Ca are connected to the contacts NC1 and NC1 ', and the normal open of the first relay 50a is connected. The contacts NO1 and NO1 'are connected to each other to the common contact C2 of the second relay 50b, and the normal open contact NO2' and the normal close contact NC2 'of the second relay 50b are connected to each other. Cooling fan motor control circuit of the refrigerator, characterized in that the second and third starting capacitor (Cb) (Cc) is connected to.