JP2777504B2 - Power supply control device for refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control device for a refrigerator, and provides a power supply control device which does not use a transformer for a PTC motor but also serves as a power supply transformer for an automatic ice maker or the like.

[0002]

2. Description of the Related Art FIG. 4 is an external perspective view showing a state in which a door of a freezer compartment of a conventional general refrigerator is opened. As shown in FIG. 4, a freezer compartment 1 is provided above the refrigerator. The freezer compartment 1 is provided with double doors 2 and 3.
When the double doors 2, 3 are closed, frost is generated at a portion where the open / close side ends of the double doors 2, 3 come into contact, and the double doors 2, 3 are prevented from freezing and opening. PTC heaters 4 and 5 as heaters for use, and an automatic ice maker 6 for automatically producing ice are provided at the upper left.

FIG. 5 is a circuit diagram showing a conventional power supply control device for a refrigerator. As shown in FIG. 5, in a refrigerator equipped with an automatic ice maker, a large amount of DC power is used for driving the automatic ice maker 6 and the like, and the transformer 21 for the PTC heater and the automatic ice maker 6 are used.
Power transformers 7 are provided separately, and PTC
PTC heaters 4 and 5 are connected in parallel to secondary terminals of the heater transformer 21. The primary terminal of the power transformer 7 is connected to an AC power source,
The primary terminal of the PTC heater transformer 21 is connected to connection points H and I between the secondary terminal and the AC power supply side. A rectifier circuit 8 for rectifying an AC voltage is connected to a secondary terminal of the power transformer 7, a minus side of the rectifier circuit 8 is grounded, and a load is connected to a plus side via a control circuit power supply unit 22. It is connected to the control circuit 18. The load control circuit 18 controls driving of loads such as a compressor 19, a fan motor 20 for circulating cool air in the refrigerator, and an automatic ice maker 6.

In the power supply control device for a refrigerator constructed as described above, if the PTC heater transformer 21 is also used as the power supply transformer 7, the resistance of the PTC heaters 4 and 5 is low when the power is turned on. As a result, the output voltage of the rectifier circuit 8 becomes lower due to the voltage drop, and the load control circuit 18 malfunctions via the control circuit power supply unit 22. In order to prevent this malfunction, the transformers are provided independently of each other.

[0005]

However, since two transformers are required for the power supply control device of the refrigerator, there has been a problem that the storage space for the electrical components has to be enlarged and the cost is high. . The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a power supply control device for a refrigerator that can share two transformers with one transformer.

[0006]

According to the present invention, there is provided a power supply control apparatus for a refrigerator, comprising: a power supply transformer, a power supply, and a power supply. A PTC heater connected to the secondary side of the transformer, a rectifying circuit for rectifying an AC voltage obtained via the power transformer, a stabilizing circuit for stabilizing an output voltage of the rectifying circuit, a compressor and indoor cold air circulation. a load control circuit for controlling the driving of the load such as use fan motor and automatic ice maker, characterized in that a and that control circuit delays the start of operation of the load control circuit immediately after power-on.

[0007]

In the above configuration, by using two transformers as one transformer, the electrical component storage portion of the refrigerator can be reduced, the effective internal volume can be increased, and the cost can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. The same parts as those of the conventional example of the present invention are denoted by the same reference numerals. FIG. 1 is a circuit diagram showing one embodiment of a power supply control device for a refrigerator according to the present invention. As shown in FIG. 1, an AC power supply is connected to a primary terminal of the power transformer 7, and a rectifier circuit 8 for rectifying an AC voltage is connected to a secondary terminal of the power transformer 7. Two PTC heaters 4, 5 are provided at connection points A and B between the power transformer 7 and the rectifier circuit 8.
Are connected in parallel. A negative side of the rectifier circuit 8 is grounded, and a stabilizing circuit 9 for stabilizing an output voltage of the rectifier circuit 8 is connected to a positive side.

The stabilizing circuit 9 includes a transistor 1
0 is provided, and the base terminal 10 a of the transistor 10 is grounded via the Zener diode 11. The collector terminal 10b of the transistor 10 in the stabilizing circuit 9 is connected to the plus side of the rectifying circuit 8 at a connection point C, and the other end of the electrolytic capacitor 12 in which one end in the stabilizing circuit 9 is grounded is connected. A connection point D connected between the connection point C and the collector terminal 10b of the transistor 10;
A resistor 13 for flowing a base power supply is connected between a connection point E between Oa and the Zener diode 11.

A microcomputer control circuit 14 is connected to a connection point F between the rectifier circuit 8 and the stabilizing circuit 9, and a microcomputer 15 is provided in the microcomputer control circuit 14. A diode 16 is connected in the microcomputer control circuit 14 on the connection point F side, and an electrolytic capacitor 17 is connected to the diode. The microcomputer 15 is connected to a connection point G between the diode 16 and the electrolytic capacitor 17, and the signal line 15 a of the microcomputer 15 is connected to the load control circuit 1.
8 is connected. Further, the stabilizing circuit 9 is also connected to the load control circuit 18, and the load control circuit 18 controls driving of loads such as the compressor 19, the fan motor 20 for circulating cool air in the refrigerator, and the automatic ice maker 6.

FIG. 2 is a time chart of various waveforms after power-on according to an embodiment of the power supply control device for a refrigerator of the present invention. FIG. 2A shows the waveform of the PTC heater current. Since the resistance value decreases due to the positive temperature characteristics of the PTC heater, an inrush current of about 3 amps (hereinafter abbreviated as A) immediately after the power is turned on. It flows and decreases after a lapse of time t _{1 to} a stable current of about 0.15 A.

FIG. 2B shows the waveform of the output voltage of the rectifier circuit. The inrush current of the PTC heaters 4 and 5 is large immediately after the power is turned on. _The voltage drops significantly to _zero . Then, the power supply voltage v with decreasing the inrush current of the PTC heater 4 and 5 rises, after time t elapses supply voltage to v ₂ is restored.
Stabilizing circuit 9 flows to the load control circuit 18 if the minimum necessary voltage v ₁ or the operation of the load control circuit 18, is not a malfunction due to normal operation of the load of the load control circuit 18.

FIG. 2C shows the waveform of the operation of the load of the load control circuit. The compressor 19, the fan heater 20 for circulating cold air in the refrigerator, and the elapse of t ₂ hours after the power is turned on.
The automatic ice maker 6 and the like are operated.

FIG. 2D shows the waveform of the microcomputer power supply voltage of the microcomputer control circuit.
Even if the output voltage of the rectifier circuit 8 drops from 12 volts (hereinafter abbreviated as V) to about 6 V due to the inrush current, the microcomputer 15 of the microcomputer control circuit 14 secures the voltage V ₃ required for operation, for example, 5 V. Therefore, the microcomputer 15 can operate normally.

FIG. 3 is a flowchart of a microcomputer program showing an embodiment of the refrigerator power supply control apparatus of the present invention. As shown in FIG. 3, and the power of the refrigerator body input, performs initial setting of the microcomputer in step S1, in step S2, the set not to perform the control of the load until the elapsed t ₂ hours after power . And
In step S3, it is determined whether or not elapsed after power-on t ₂ hours, when it is determined that YES, the process advances to step S4, the control load is operated. NO in step S3
If it is determined that without the operation of willing control load to step S5, not controlled load until t ₂ hours after the return after power before step S2. This program is repeated many times unless t ₂ hours elapse.

In the above-described embodiment, since the resistance of the PTC heater is low immediately after the power is turned on due to the positive temperature characteristic, a large inrush current flows through the PTC heater, and the output voltage of the rectifier circuit drops. In order to eliminate the malfunction of the load control circuit, the microcomputer sends a preset signal to the load control circuit, and the stabilization circuit executes a program in which the load control circuit does not operate until the output voltage of the rectifier circuit becomes stable. By setting in the microcomputer, one transformer can be used.

[0017]

Since the power supply control device for a refrigerator according to the present invention is constructed as described above, it is possible to eliminate a malfunction of an automatic ice maker or the like due to a rush current of a PTC heater.
In addition, by being used also as a power transformer, the electrical component storage portion can be made small and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a power supply control device for a refrigerator according to the present invention.

FIG. 2 is a time chart of various waveforms after power-on according to an embodiment of the power supply control device for a refrigerator of the present invention;
(A) is a waveform diagram of a PTC heater current, (b) is a waveform diagram of an output voltage of a rectifier circuit, (c) is a waveform diagram of a load operation of a load control circuit, and (d) is a microcomputer power supply voltage of a microcomputer control circuit. FIG.

FIG. 3 is a flowchart of a program of a microcomputer showing an embodiment of a power supply control device for a refrigerator according to the present invention.

FIG. 4 is an external perspective view showing a state in which a door of a freezer compartment of a power supply control device of a conventional general refrigerator is opened.

FIG. 5 is a circuit diagram showing a conventional power supply control device for a refrigerator.

[Explanation of symbols]

 4, 5 PTC heater 7 Power transformer 9 Stabilization circuit 14 Microcomputer control circuit 18 Load control circuit

Claims (1)

(57) [Claims] 1. A power supply control device for a refrigerator having a heater for preventing a door from freezing in a freezing compartment of the refrigerator, comprising: a power transformer; and a positive temperature characteristic ceramic heater (hereinafter referred to as a PTC heater) connected to a secondary side of the power transformer. Abbreviated), a rectifier circuit for rectifying an AC voltage obtained via the power transformer, a stabilizing circuit for stabilizing an output voltage of the rectifier circuit, a compressor, a fan motor for circulating cool air, an automatic ice maker, and the like. a load control circuit for controlling the driving of the load of a refrigerator of the power supply control apparatus is characterized by providing a slow <br/> racemate Ru control circuit operation start of the load control circuit immediately after power-on.