KR970004345B1 - Method for defrosting heat automatic return of refrigerators - Google Patents

Abstract

The automatic returning method of a defrost heater in a refrigerator comprises the steps of: if a defrost mode is on, reading a temperature value sensed by a defrost sensor to compare the read temperature and a first heater off temperature; if the temperature value of the defrost sensor is over the first heater off temperature, stopping the heating of the defrost heater; if under the first heater off temperature, determine whether a set delay time elapses; if the delay time has elapsed, reading a temperature value sensed by a temperature sensor for a freezing chamber to compare the read temperature value with a second heater off temperature; if the temperature value is over the second heater off temperature, stopping the heating of the defrost heater.

Description

Automatic defrost heater return method

1 is a hardware block diagram of a refrigerator to which the present invention is applied.

2 is a control flowchart showing a method of automatically returning a defrost heater of the present invention.

* Description of the symbols for the main parts of the drawings *

10: micom 20: temperature detection unit

30: compressor driving unit 40: fan driving unit

50: heater driving unit TH1-TH3: temperature sensor

HTR: Defrost heater RY1-RY3: Relay

The present invention relates to a failure diagnosis and improved safety of a refrigerator. In particular, when the defrost heater generates heat, even if a defect occurs in the defrost sensor, the temperature sensor for the freezer compartment detects the off temperature of the defrost heater and automatically generates heat to generate heat. The present invention relates to a method for automatically returning a defrost heater to a refrigerator so as to prevent malfunctions or malfunctions caused by the refrigerator.

In general, the refrigerator has a defrost heater to remove frost generated around the evaporator. If the accumulated operation time of the compressor is more than a predetermined time (for example, 9 hours), the defrost is unconditionally entered, and the cumulative time of the compressor is a predetermined time (for example; If the cumulative door opening time is longer than a predetermined time (for example, 10 minutes) in a state of 6 hours or more, the defrost is started at that time.

When entering the defrost mode, the defrost heater detects the ambient temperature of the evaporator while heating the defrost heater. When the temperature detected by the defrost sensor reaches the set heater off temperature (eg 13 ℃), the defrost heater automatically stops heating. However, if the temperature sensed by the defrost sensor is below the set heater off temperature, the defrost heater is turned off after being heated for a set time (eg, 90 minutes).

However, in this method, if the defrost sensor is not detected during the defrosting and the heater off temperature is not detected, the defrost heater continues to generate heat. It malfunctions and turns off after the defrost heater generates heat for a set time.

Therefore, after-sales service is required to replace broken defrost sensor and defective defrost sensor. If the defrost heater continues to generate heat, the freezer temperature rises to a certain temperature, so the food inside the freezer melted. There was a problem of freezing again.

The present invention is to solve the above conventional problems, an object of the present invention is to check the temperature together with the temperature sensor for the freezer compartment of the defrost sensor when in the defrost mode, even if the defrost sensor has a set heater off temperature is When the defrost heater is turned off automatically to improve the safety to provide a defrost heater automatic return method.

Another object of the present invention is to provide a method for automatically returning a defrost heater to a refrigerator to prevent food inside the freezing chamber from melting or spoiling and to reduce the need for after-sales service due to a refrigerator failure.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the attached FIGS. 1 and 2.

1 is a hardware configuration diagram of a refrigerator to which the present invention is applied.

As shown in the drawing, the refrigerator of the present invention senses the temperature of the microcomputer 10 for controlling the overall operation related to the internal temperature control, the internal temperature of the freezer compartment and the refrigerating compartment and the evaporator temperature at the time of defrosting, and inputs it to the microcomputer 10. The detection unit 20, the compressor drive unit 30 for switching the AC power supply AC to the compressor COMP according to the control signal of the microcomputer 10, and for operating or stopping the compressor, and the control signal of the microcomputer 10. According to the control signal of the microcomputer 10 and the fan drive unit 40 for switching the AC power supply AC to the fan F, and the AC power supply AC to the defrost heater HTR. It is composed of a heater drive unit 50 for switching the supply to heat or turn off the defrost heater.

Here, the temperature sensing unit 20 is installed in the freezer compartment and the first temperature sensor (TH1) that the resistance value is variable according to the temperature, and the second temperature sensor (TH2) is mounted in the refrigerating compartment and the resistance value varies depending on the temperature And a defrosting sensor TH3 mounted around the evaporator and having a variable resistance value according to the temperature at the time of defrosting, and connected to the temperature sensors TH1-TH3, respectively, for distributing a voltage Vcc. And a resistor (R4-R6) and a capacitor (C1-C3) for dropping and stabilizing the temperature values divided by the temperature sensors (TH1-TH3) and resistors (R1-R3), respectively, and inputting them to the microcomputer (10). It consists of.

The microcomputer 10 compares the internal temperature sensed by the temperature sensors TH1 and TH2 with the set temperature in order to maintain the internal temperature at the set temperature, and according to the comparison result, the compressor driver 30 and the fan driver 40. The control signal is outputted to repeat the operation and stop operation continuously.

The compressor driving unit 30 includes an inverter INV1 for inverting the output signal of the microcomputer 10, a relay RY1 turned on / off according to the output signal of the inverter INV1, and a diode connected across the relay RY1. (D1) and the compressor (COMP) which is switched on or off as the AC power supply is switched as the relay RY1 is turned on / off.

Similarly, the fan driver 40 includes an inverter INV2 for inverting the output signal of the microcomputer 10, a relay RY2 turned on / off according to the output signal of the inverter INV2, and both ends of the relay RY2. The connected diode D2 and a fan FAN are switched and rotated or stopped as the AC power supply is switched on and off.

The heater driving unit 50 is connected to both ends of the inverter INV3 for inverting the output signal of the microcomputer 10, the relay RY3 turned on / off according to the output signal of the inverter INV3, and the relay RY3. The diode D3 and the defrost heater HTR are switched on and off as the relay RY3 is turned on and off.

2 is a control flow chart showing the automatic defrost heater recovery method of the present invention.

First, the microcomputer 10 enters the defrost mode when the accumulated operating time of the compressor is equal to or longer than the set time or when the cumulative opening time of the compressor is equal to or greater than the predetermined time.

When the motor enters the defrost mode, the microcomputer 10 outputs a high potential signal to the heater driver 50, which is inverted by the inverter INV3 and then applied to one side of the relay RY3. The current flows and is driven, whereby the relay RY3 switch is connected, so that the AC power source AC is supplied to the defrost heater HTR to generate heat.

When the defrost heater HTR generates heat as described above, the ambient temperature value of the evaporator detected by the defrost sensor TH3 is read (step 102), and the heater off temperature is set to the temperature value detected by the defrost sensor TH3. (Example; 13 ° C) (step 103).

When the temperature value detected by the defrost sensor TH3 is lower than the heater off temperature, the temperature value of the defrost sensor TH3 returned to step 101 is continuously checked, and the detected temperature value is equal to or higher than the heater off temperature. In this case, a low potential signal is output to the heater driver 50 to stop the heat generation of the defrost heater HTR and complete the defrost (step 107).

At this time, since the low potential signal input to the heater driver 50 is inverted by the inverter INV3, no current flows in the relay RY3. When the relay RY3 is turned off, the relay RY3 switch is opened so that the AC The power source AC is cut off and the defrost heater HTR stops heating.

If the temperature value of the defrost sensor TH3 continuously read in step 101 is lower than the set heater-off temperature due to poor characteristics of the defrost sensor, it is determined whether the set delay time (eg, 10 minutes) has elapsed. (Step 104).

If the set delay time has elapsed, the internal temperature value of the freezer compartment detected by the first temperature sensor TH1 is read (step 105), and the temperature value detected by the first temperature sensor TH1 is compared with the designated heater off temperature. Compare (step 106).

When the temperature value detected by the first temperature sensor TH1 is lower than the heater off temperature, the process returns to step 101 and the above-described process is repeated. When the detected temperature value is higher than the heater off temperature, the heater driver ( The low potential signal is outputted to 50) to stop the heat generation of the defrost heater HTR, and complete the defrost (step 107).

Here, the heater off temperature compared to the internal temperature value of the freezer compartment detected by the first temperature sensor TH1 is a value determined by many experiment data, and is compared with the evaporator ambient temperature value detected by the defrost sensor TH3. The heater off temperature is another value.

As described above, the present invention allows the defrost sensor and the temperature sensor mounted in the freezing chamber to check the temperature together when entering the defrost mode. This prevents the food inside the freezer from melting or spoiling.

In addition, it is possible to reduce the need for after-sales service due to the refrigerator failure, it is possible to improve the safety.

Claims (1)

Reading the temperature value sensed by the defrost sensor when the defrost mode is started and comparing it with the set first heater on temperature; Stopping heat generation of the defrost heater when the temperature value of the defrost sensor is greater than or equal to the first heater off temperature; Determining whether a set delay time has elapsed when a temperature value of the defrost sensor is lower than a first heater off temperature; Reading a temperature value detected by a temperature sensor for a freezer compartment and comparing it with a set second heater off temperature when the set time elapses; When the temperature value of the temperature sensor for the freezer compartment is lower than the second heater off temperature, the process returns to the initial stage and continuously checks the temperature value of the defrost sensor, and when the temperature value of the temperature sensor for the freezer compartment is higher than the second heater off temperature, the defrost heater Defrost heater automatic return method of the refrigerator, characterized in that the control to stop the heat generation.