JPS60228872A - Driving circuit for defrostation of cooling device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a defrosting drive circuit for a cooling device such as a refrigerator, which starts defrosting operation of a cooler in a cooling device.

[Technical background of the invention]

Conventionally, in a cooling device such as a fan-type refrigerator that uses a fan to circulate cold air from the cooler into the freezing chamber, an electronic timer is installed to count the total operating time of the compressor. A configuration has been proposed in which the defrosting operation of the cooler is started every time a timer finishes counting a set time, for example, 30 hours.

[Problems with background technology]

In the conventional configuration described above, if the power to the refrigerator is momentarily cut off, the electronic timer is reset even in the middle of timing operation, so when the power outage is restored, the timer starts timing operation from the beginning using the RC system. , Therefore, the time until the start of defrosting operation of the cooler is the above-mentioned set time 3
There was a problem that when the time was longer than 0 hours, the cooler became overly frosted.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and provides a defrosting drive circuit for a cooling device that can reliably prevent the cooler from becoming overloaded even if the power supply of the cooling device is cut off. The purpose is to

[Summary of the invention]

The present invention provides a normal operation timer that outputs a defrosting start signal to start the defrosting operation of the cooler of the cooling device every time the normal setting time ends, and the initial period is shorter than the normal setting time. An initial operation timer is provided which outputs the same defrosting start signal as described above each time the clocking operation for the set time is completed, and when power supply to the cooling device is detected, the initial operation timer is selected and the initial operation timer is activated. The feature is that a power state detection circuit is provided to select the normal operation timer after the timing operation is finished, and the time until the start of the first defrosting operation after power is supplied to the cooling device is determined. Second
This is shorter than the time it takes to start the next defrosting operation.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a DC power supply terminal, to which a DC voltage +V obtained by rectifying the AC voltage of an AC power supply supplied to the refrigerator, which is a cooling device, is applied. 2 is a control V sensor consisting of a negative characteristic thermistor, which senses the temperature inside the freezing chamber. This controller sensor 2 is connected between the DC power supply terminal 1 and the ground via a resistor 3 in series.
A series circuit of resistors 4 and 5 is connected in parallel to this series circuit. The detection terminal 6, which is the common connection point of the control sensor 2 and the resistor 5, is connected to the positive (a) input terminal VC of the comparison circuit 7, and the reference terminal 8, which is the common connection point of the resistances 4 and 5, is connected to the comparison circuit 7. A negative (-) input terminal VC is connected, and a negative feedback resistor 9 is connected between the output terminal of the comparator circuit 7 and the negative (-) input terminal. Furthermore, the output terminal of the comparator circuit 7 is connected to an NPN type transistor 110 through a resistor 10T, and the emitter of this transistor 11 is grounded, and the collector is connected to a DC power supply terminal through a 12K relay for driving the compressor. 1
1C connected. In this case, when the relay 12 is energized, it closes the energized path of the drive motor of the compressor of the refrigeration system and the drive motor of the fan, and when the relay 12 is turned off, it opens the energized path. I' to circulate the cold air from the refrigerator's cooler into the freezer compartment.
l(becomes.

A portion of the cold air from the cooler is also circulated into the refrigerator compartment. Therefore, the above control sensor 2. Comparison circuit 7. The transistor 11, the relay 12, etc. constitute a temperature control circuit 13.

Now, the configuration of the defrosting drive circuit 14 will be described.

15 and 16 are a capacitor and a resistor for detecting the supply of AC power to the refrigerator, and these are connected in series between the DC power supply terminal 1 and the ground, and the detection terminal 17, which is the common connection point, is A set input terminal 8rc of an R8 type flip-flop circuit 18 is connected. 19
and 20 are the capacitors 15. It is an AND circuit that constitutes the power state detection circuit 21 together with the resistor 16 and the flip-flop circuit 18, and one input terminal of each of these circuits is connected to the output terminal of the comparison circuit 7. The input terminals of the output terminals 19 and 90 are respectively connected to the set output terminal Q and the reset output terminal 18 of the flip-flop circuit 18.

22 is a timer for initial operation consisting of a binary counter, its enable terminal E is connected to the output terminal of the AND circuit 19, the clock terminal OK is connected to the output terminal of the clock pulse generator circuit 23, and the output terminal Oi; :
It 8 type flip-flop circuit 240 set input terminal 8vC is connected. In this case, the clock bus TV generation circuit 23 is configured to generate a clock pulse V at regular time intervals, and performs a timekeeping operation by counting the clock pulse W given from the slave CKVC clock pulse generation circuit 25. The initial operation timer 22 is configured to output a defrosting start signal Sx2, which is a high level/V output signal, from the output terminal O every time the initial operation timer 22 completes the timing operation for the initial set time (for example, 5 hours). There is. 25 is a normal operation timer 0 consisting of a binary counter, its enable terminal E is connected to the output terminal of the AND circuit 20, the clock terminal CK is connected to the output terminal of the clock pulse generation circuit 26, and the output terminal 0#IR8
It is connected to the set input terminal 8 of the flip-flop circuit 27 of the form.

In this case, the clock bus zV bus generating circuit 26 generates the clock pin IV similarly to the clock bus bus generating circuit 26, and the normal operation timer 25 receives the signal from the enable V terminal Evc high Vpeν. While the clock is being supplied, the clock basis generation circuit 26 is connected to the clock terminal OK.
The normal operation timer 25 outputs a high-level V output signal from the output terminal O every time the normal operation timer 25 completes the time measurement operation for the normal set time (for example, 30 hours). A barrel defrosting start signal 825 is output. Furthermore, each set output terminal Q of the flip-flop 71 circuits 24 and 27 is connected to one input terminal and the other input terminal of an OR circuit 28, respectively, and the output terminal of the OR circuit 28 is connected to an NPN transistor 30 via a resistor 29. connected to the base. In this transistor 301C, the emitter is grounded, and the collector is connected to the DC power supply terminal 1rc via the defrosting heater driving relay 31. In this case, when the relay 51 is energized, it closes the energizing path of the defrosting heater connected to the cooler vclt, and when the relay 51 is deenergized, it opens the energizing path. Therefore, the OR circuit 28
The output terminal of is branched via the inverter circuit 32,
One branch end thereof is connected to the output terminal of the comparator circuit 7 via a diode 33 with the polarity shown, and the other branch end is connected to the initial operation timer 22 and the normal operation timer 25 via a diode 34 with the polarity shown. are connected to each reset terminal R of. Reference numeral 35 is a debris removal sensor made of a negative characteristic thermistor, which senses the temperature of the cooler. This dust removal sensor 35 is connected between the DC power supply terminal 1 and ground via a resistor 36 in series, and a series circuit of resistors 37 and 38 is connected in parallel to the series circuit. Reference numeral 39 is a comparison circuit that constitutes the removal end detection circuit 4D together with the waste removal sensor 35 and the resistors 56 to 38, and its positive (+) input terminal is connected to the removal waste sensor 3.
The negative (-) input terminal is connected to a reference terminal 42 that is a common connection point of resistors 37 and 38, and the output terminal is connected to a detection terminal 41 that is a common connection point of the flip-flop circuits 24 and 27. Each reset input terminal Rib
It is connected.

Next, the operation of this embodiment will be explained.

When AC power is turned on to the refrigerator, DC voltage +V is applied to the DC power terminal 11C, and accordingly, the detection voltage ■6 and the reference voltage ■ are applied to the detection terminal 6 and the reference terminal 8, respectively. 8 occurs. In this case, when the power is turned on to the refrigerator, the temperature inside the freezer compartment is higher than the upper limit set temperature (for example, -15°C), so it is detected from the reference voltage V8 (2, which indicates approximately -15°C in terms of temperature) generated at the reference terminal 8. Since the detection voltage v6 generated at terminal 6 is larger, comparison circuit 7
generates a high level ν output signal. As a result, transistor 11 is turned on and the compressor drive relay is turned on.
When the compressor of the refrigeration cycle is driven so that the 12vC current is applied, the 41C fan is driven, and therefore,
Cooling operation is started.

On the other hand, when a DC voltage is applied to the DC power supply terminal 1, a current flows through the capacitor 15 and the resistor 161C for a short period of time until the capacitor 15 is fully charged.
The detection voltage Vzy of high level ν is generated for a short period of 7vc, thereby setting the flip-flop circuit 18 and the set output signal of the set output terminal Q becomes high Vbay. At this time, the output signal of the comparator circuit 7 is at a high level ν, so the output signal of the AND circuit 19 becomes a high level ν, and the initial operation timer 22 is selected. The clock valve rV from the MS generation circuit 23 is counted to start the timekeeping operation. Thereafter, when the temperature inside the freezer reaches the lower limit setting temperature (for example -20°C), the reference voltage v8 changes to approximately -20°C based on the action of the negative feedback resistor 9 of the comparator circuit 7.
Since it corresponds to CvC, when the detection voltage V6 is smaller than the reference voltage V8, the output signal of the comparator circuit 7 becomes low level ν, the transistor 11 is turned off, and the relay 12 is cut off by 9%. The compressor and fan will be shut down. Then, as the output signal of the comparison circuit 7 becomes low level ν, the output signal of the AND circuit 19 also becomes low level ν, and the initial operation timer 22 interrupts the timing operation.

Thereafter, when the temperature inside the freezing chamber reaches the upper limit setting temperature, the output signal of the comparator circuit 7 becomes high level ν, the compressor and fan are driven again, and the initial operation timer 22 restarts the timing operation. The following similar movements f'lli
By repeating this, the compressor and fan are operated intermittently to control the temperature inside the freezing chamber between the upper limit temperature and the lower limit temperature, and the initial operation timer 22 starts to count the total operating time of the compressor. do.

When the initial operation timer 22 finishes counting the initial set time (for example, 5 hours 2), the initial operation timer 22 outputs a defrosting start signal 8u, which is a high level ν output signal, from the output terminal O. Vc, the defrosting start signal 822 of this high level ν sets the shift flip-flop circuit 24, and the set output signal of the set output terminal Q becomes high level V, and the flip-flop circuit 18
is reset, and the reset output signal of the reset output terminal becomes high level V. Furthermore, the flip-flop circuit 2
Based on the fact that the set output signal of No. 4 becomes high level V, the output signal of the OR circuit 28 becomes high level ν and is outputted as the defrosting signal 828, and the transistor 30 is turned on by this defrosting signal 82sK. Relay 31
The relay 31 closes the energization path of the defrosting heater, and the defrosting heater heats the cooler and starts defrosting operation. Further, when the defrosting signal 828 of high level ν is output from the OR circuit 28, the output signal of the inverter circuit 32 is not equal to the low level ν, so the output signal of the comparator circuit 7 becomes the low level V via the diode 53. , the transistor 11 is turned off, the compressor and the fan are stopped, and the output signal of the inverter circuit 32 becomes low level ν, so that each reset terminal R of the initial operation timer 22 and the normal operation timer 25 is connected to the diode 3.
4 through low level V and both timers 22 and 25
is reset to its initial state.

When the defrosting of the cooler is completed and the temperature of the cooler reaches the positive set temperature, the detection voltage Va+ generated at the detection terminal 41 becomes larger than the reference voltage V42 generated at the reference terminal 42Vc, and the comparison circuit 39 When the output signal reaches the high level ν, the flip-flop circuits 24 and 27 are reset, and the output signal of the flip-flop circuit 24 becomes low level ν9, and the OR circuit 28 stops outputting the defrosting signal 8za.

Therefore, the transistor 30 is turned off, cutting off the power to the relay 31, and the relay 31 comes to open the energizing path of the defrosting heater, thereby ending the defrosting operation.
When the output of the defrosting signal 826 from the inverter circuit 52 is stopped, the output signal of the inverter circuit 52 becomes high level ν, and accordingly, the output signal of the comparator circuit 7 becomes high level ν.
9, the relay 12 is energized and the cooling operation is restarted. Further, the high level ν output signal of the comparator circuit 7 is given to AND circuits 19 and 201C, but at this time, since the reset output signal of the reset output terminal Q of the 1'CH flip-flop circuit 18 is high level ν, the AND circuit The output signal of 20 becomes the high repeat v, and the normal operation timer 25 is selected this time, and the normal operation timer 25 counts the clock pulses from the clockbasis generation circuit 26 and starts timekeeping operation.

The normal operation timer 25 operates in the same manner as the initial operation timer 22, and operates to count the cumulative operating time of the compressor. Then, when the normal operation timer 25 finishes counting the normal set time (for example, 60 hours), the normal operation timer 25 starts outputting the defrosting start signal 825, which is a high-level ν output signal. Based on this, the OR circuit 28 outputs the defrost signal 828.The operation of stopping the cooling operation and starting the defrosting operation is the same as described above, and the timer 25 for normal operation is reset. After that, when the defrosting of the cooler is completed, the output signal of the comparator circuit 39 becomes high rep ν, which resets the flip-flop circuit 27, and the output of the defrost signal 82s from the OR circuit 28 becomes The defrosting operation is stopped and the cooling operation is restarted in the same manner as described above.

However, the flip-flop circuit 1 of the power state detection circuit 21
Since the reset output terminal 8 has been outputting the reset output signal of the high-repe V since summer, the normal operation timer 25 performs the timekeeping operation 1' (after that).

Therefore, if the AC power supply to the refrigerator is interrupted even momentarily during the cooling operation or defrosting operation as described above, the DC voltage applied to the DC power supply terminal 1 will also disappear, so that the initial operation timer 22 and normal operation will be interrupted. Both timers 25 are reset to their initial states. After that, when the AC power is restored, DC voltage is applied to the DC power supply terminal 1 again, so the flip-flop circuit 18 is set so that the detection voltage V17 is generated for a short time at the detection terminal 171C, and the set output is The set output signal at the terminal Q becomes high repeat ν, and the initial operation timer 22 is selected again. The subsequent operations are the same as described above.

As described above, according to this embodiment, the normal operation timer 25, which measures the normal set time (for example, 30 hours),
In addition, an initial operation timer 22 is provided to time an initial set time (for example, 5 hours) that is shorter than the normal set time, and a power state detection circuit 21vc detects the supply of AC power to the refrigerator. When the c6-1 initial operation timer 22 is selected, and after the initial operation timer 22 finishes measuring, the normal operation timer 25 is selected, so even if the refrigerator's AC power supply fails, there is no power outage. Defrosting operation of the cooler will start after the initial set time (for example, 5 hours) has passed after the power is restored. Unlike the conventional method in which the defrosting operation is not started, it is possible to reliably prevent the cooler from becoming overly frosted.

Although the above embodiments describe six cases in which the present invention is applied to a refrigerator, the present invention is not limited to this, and for example, it can be applied to a refrigerator.
7. It goes without saying that the present invention can be modified as appropriate without departing from the scope of the invention, such as being applicable to IC.

〔Effect of the invention〕

As explained above, the defrosting drive circuit for the cooling device of the present invention selects the initial operation timer that measures the initial setting time, which is shorter than the normal setting time, when power supply to the cooling device is detected. After the initial operation timer finishes counting, the normal operation timer that measures the normal setting time is selected, so even if the cooling device's power is cut off, the cooler will not be overloaded. This has the excellent effect of reliably preventing frost conditions.

[Brief explanation of the drawing]

The figure is an explanatory diagram of an electrical configuration showing an embodiment of the present invention. In the drawing, 2Fi controller ν sensor, 12 [compressor drive relay, 15 temperature control circuit, 14 defrost drive circuit, 211d power state detection circuit, 22#: initial operation timer, 25id normal operation timer, 31 35 is a defrosting sensor, and 4D is a defrosting completion detection circuit.

Claims (1)

[Claims] 1. A normal operation timer that outputs a defrosting start signal to start the defrosting operation of the cooler of the cooling device every time the normal set time ends, and an initial set time that is shorter than the normal set time. An initial operation timer outputs the same defrosting start signal as described above each time the timing operation ends, and when power supply M to the cooling device is detected, the initial operation timer is selected and the initial operation timer starts the timing operation. A defrosting drive circuit for a cooling device, comprising: a power state detection circuit that selects the normal operation timer after completion of the normal operation.