JPS62225854A - Air conditioner - 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 The present invention relates to an air conditioner, and more particularly to a control device that performs control by detecting a drop in power supply voltage.

<Prior art> Conventional air conditioner control devices do not have voltage detection circuits, so when the power supply is poor or the power cable is extremely long, a large current (
For example, when 40rlLA) flows, a voltage drop occurs instantaneously. As a result, the compressor cannot be started, and the starting current continues to flow for a while until the safety device operates, causing the compressor to stop. In such a case, the problem could easily be mistaken for a failure of the air conditioner itself, and the repeated operation of the protection device could eventually damage the device itself.

<Purpose> In view of the above, the present invention aims to provide an air conditioner that can prevent damage to the main body of the device due to a drop in power supply voltage by providing a function to detect a drop in power supply voltage.

<Embodiment> Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 5. An air conditioner according to the present invention includes a heat medium cycle 2 having a compressor 1 that compresses and discharges a heat medium. and the compression P
A power supply circuit 3 that supplies power to Ii1, a voltage detection circuit 4 that detects the power supply voltage of the power supply circuit 3, and a control circuit 5 that controls the compressor 1 based on the output signal of the voltage detection circuit 4.
The control circuit 5 compares the output value of the voltage detection circuit 4 with a set value and outputs a signal to stop the compressor 1 when the output value is lower than the set value. It is something that has a function.

The control circuit 5 also has a display function for outputting an alarm signal to the display device A during the output of the comparison/judgment 811 function.

FIG. 5 is a configuration diagram of an air conditioner according to the present invention, in which the heat medium cycle 2 includes a compressor 8!1 for discharging refrigerant, and an outdoor heat exchanger 6 connected to the discharge side of the compressor 1. , an indoor heat exchanger 8 whose negative side is connected to the outdoor heat exchanger 6 via a pressure reducer 7, and whose other side is connected to the compressor 1.

An outdoor blower 9 is disposed in the outdoor heat exchanger 6, and an indoor blower 10 is disposed in the indoor heat exchanger 8.

FIG. 1 is a circuit diagram of the control device, in which 11.11a is the power source of the power supply circuit 3, 12 is an electronic control circuit unit using a microcomputer, has relay outputs 13.14, and the relay contacts of the relay 13. Indoor blower 10 with 13a,
The outdoor blower 9 and the upstream compressor 1 are controlled by relay contacts 14a of the relay 14, respectively.

FIG. 2 is a detailed diagram of the electronic control unit 12. Reference numeral 15 is a transformer for converting the power supply voltage to a low voltage, and a closed circuit of the transformer 15 and the power supplies 11 and 11a constitutes the power supply circuit 3. 16 is a DC constant voltage circuit 16 that converts the AC voltage stepped down by the transformer 15 into a DC constant voltage. The power output from the constant voltage circuit 16 is supplied to each control element through a positive side 17 and a ground side 18.

The control circuit 5 is a general one-chip microcomputer, and internally includes a program ROM, data RAM, and AL.
In synchronization with the signal from the reference clock oscillation circuit 19, instructions in the program ROM are sequentially read and analyzed, data is read from the input ports (INI to IN4), and data is read from the input ports (INI to IN4), and the output ports (OUT1) ~0UT4 outputs data.

20 is an operation switch connected to the input capo (INI) of the control circuit 5, and 21 is a pull-down resistor. Reference numeral 22 denotes a thermistor for detecting room temperature, and its resistance and resistance change are sent to the control circuit 5 as a voltage (room temperature data) divided by a voltage dividing resistor 23.
input port) IN2 (analog input port).

The voltage detection circuit 4 includes a voltage transformer 24 for converting the power supply voltage into a low voltage and inputting it to the analog input capacitor IN3 of the control circuit 5, and a diode for rectifying the AC low voltage stepped down by the voltage transformer 24. 25 and the diode 2
5 and a smoothing capacitor 26 for smoothing the rectified voltage.

The output, which has become a direct current at the smoothing capacitor 26, is input as voltage data to the analog input capacitor (IN3) of the control circuit 5 through the resistor 27. Note that 28 is a discharge resistor.

Reference numeral 29 is a variable volume for setting the room temperature, and the voltage is divided by a resistor 30 and inputted to the analog input capacitor (IN4) of the control circuit 5 as room temperature setting data.

31 is a transistor array for controlling the relay 13, the relay 14, and the LED 27 as the display device A;
The output of the control circuit 5 is controlled from OUT1 to 0UT3. 32 is a resistor, and LED 3 as display device A
This is for limiting the current of No. 3.

Next, the operation will be explained. First, when the operation switch 20 is pressed, an H signal is input to the input port (INI) of the control circuit 5, and the H signal is input to the output port of the control circuit 5.

An H signal is output to the UTI, the relay 13 is turned on, and the indoor ventilation filO starts the ventilation operation. Then enter the capo)
Read the room temperature data from IN2 and input it) IN4
Compare the room temperature setting data read from , and if the room temperature is higher, output a signal to output port 01JT2 and relay 1
Turn on 4 and turn on compression 8!11 and outdoor ventilation 8!9.
Press N to start cooling operation.

The refrigerant discharged from the compressor 8!1 is condensed and liquefied in the outdoor heat exchanger 6, decompressed in the pressure reducer 7, evaporated in the indoor heat exchanger 8, and cooled by blowing cold air into the room by the indoor blower 10. Drive.

When the cooling operation continues for a while and the room temperature decreases, the resistance value of the thermistor 22 increases, and the voltage input to the control circuit 5's input capo IN2 decreases, causing the input capo to decrease.
When the voltage becomes lower than the voltage input to IN4, it means that the room temperature has reached the room temperature set value, so a low voltage is applied to the output port 0UT2.
A signal is output, the relay 14 is turned off, the compressor 1 and the outdoor blower 9 are set to 0FFL, and only the indoor blower 10 is in the air blowing operation.

The above is a general explanation of the operation.

Next, the characteristic operation of the present invention will be explained.

First, the power supply voltage of the power supply circuit 3 is input by the voltage detection circuit 4 to the input capacitor (INS) of the control circuit 5.

That is, the voltage stepped down by the voltage transformer 24 is smoothed into direct current by the diode 25 and the capacitor 26, and is then supplied to the power supply 11.
．． The voltage is inputted to the input port IN3 of the control circuit 5 through the resistor 27 as a DC low voltage proportional to the voltage of the voltage across the terminal 11a.

The control circuit 5 constantly checks the voltage value, and if the voltage value drops below a certain value, for example 82V, the output capo OUTI is set to 0FFL and the compressor 1 is turned off.
At the same time, the output capacitor OUT3 is turned on to light the LED 33 to warn of a drop in the power supply voltage.

A drop in power supply voltage becomes a problem mainly when the compressor 1 starts up and during operation. An example of this will be explained with reference to FIG. In Figure 4, the vertical axis shows voltage and the horizontal axis shows time. Compression Pl
While i1 is stopped, the voltage is set to, for example, 100 V, and when the compressor 1 starts at point A, a starting current flows and the voltage drops instantaneously (point B) to, for example, 90 V. If the rotation of compression 8!1 becomes stable (0 point), the voltage will be 95V, for example.

In such a case, generally speaking, if the voltage at point B is below a certain level, compression is possible! 1 cannot be started, becomes locked, and the starting current continues to flow. In that case, as mentioned above,
Either the safety device (not shown in Figure 2) will trip or the power breaker will trip.

Therefore, in the present invention, the operating limit voltage of the compressor 1 is checked by detecting the voltage after point B or point 0 in FIG. The alarm is issued by a display device A such as an LED 33. Therefore, it is possible to clearly distinguish between a failure of the air conditioner and a drop in voltage, so that the failure can be repaired quickly.

Further, after the compression 8!1 is stopped, the stop is forcibly continued for a certain period of time, and then the original state is automatically restored again, and the compressor 1 is restarted. In this case, normal operation can be automatically restored if the cause of the power supply voltage drop is removed.

The above operation will be explained with reference to 70-chart in FIG. 3. This 70-chart is a subroutine of a part of the entire program, and only the portions that are characteristic of the present invention are extracted.

First, enter from IN and check the voltage flag at 40. The voltage flag is normally [0], and when the voltage drops, compression I! When 1 is stopped, it is [11]. If the flag is [01, go to 41, check the voltage because it is in normal operation, and if the input data of control circuit 5 IN3 is above the set value, it is normal, so it is 42.43. Each L
Clear ED33 and OFF timer and return.

If the voltage falls below the set value at 41, enter 44 and set the voltage flag to 1.
Set to 11. Then, the next time it enters IN, it goes from 40 to 45, outputs rLJ to output capo) OUT2, compresses 8!11 to 0FFL, and outputs rHJ to output capo) OUT3.
is output, turns on the LED 33, counts the timer at 47, and enters the voltage drop alarm state.

Next, enter 48 and check the timer time up.
If the time is not up, the program returns as is, and if the time is up, the voltage flag is cleared and the program returns.

In the above explanation, the voltage was detected at one point, but as mentioned in the explanation of Figure 4, the voltage changes at two points, the B point and after the 0 point, so the voltage setting value at the B point and after the 0 point By providing two types of voltage setting values for control, more effective control can be achieved.

In addition, when a voltage drop is detected, the system goes into an alarm state and automatically returns after a certain period of time, but for example, it counts the number of times this occurs, and if it exceeds a certain number of times, it completely stops, thereby eliminating wasteful compression. The machine may not be restarted.

If the present invention is applied to a control device for an air conditioner equipped with a recent inverter device, the operating frequency of the compressor can be automatically lowered to lower the current when the voltage drops, and the compressor can be stopped. It also becomes possible to perform linear control.

<Effects> As is clear from the above description, the present invention provides a heating medium cycle having a compressor that compresses and discharges a heating medium, a power supply circuit that supplies power to the compressor, and a power supply voltage of the power supply circuit that is detected. and a control circuit that controls the compressor using an output signal of the voltage detection circuit, and the control circuit compares the output value of the voltage detection circuit with a set value to determine whether the output value is The present invention relates to an air conditioner characterized in that it has a comparative determination function that outputs a signal to stop the compressor when the value is lower than a set value.

Therefore, according to the present invention, by detecting the power supply voltage, it is possible to check the operating limit voltage of the compressor, and when the voltage falls below the limit voltage, the compressor is stopped, thereby preventing damage to the air conditioner. It has excellent effects.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of a control device for an air conditioner showing an embodiment of the present invention, Figure 2 is a detailed diagram of the control circuit, Figure 3 is a control flowchart, and Figure 4 is the voltage after the start of operation. The change characteristic diagram, FIG. 5, is a heat medium cycle diagram. 1: Compressor, 2: Heat medium cycle, 3: Power supply circuit, 4: Voltage detection circuit, 5: Control circuit, 6: Outdoor heat exchanger, 7: Pressure reducer, 8: Indoor heat exchanger, 9: Outdoor blower , 10: Indoor blower, 11.11a: Power supply, 12: Electronic control circuit unit, 13.14: Relay, 13a, 14a: Relay contact, 15 Nidorance, 16: Constant voltage circuit, 17: Positive side, 18 Nigeround side, 19: Oscillation circuit, 20: Operation switch, 22: Thermistor, 23: Voltage dividing resistor, 24:
Voltage transformer, 25: diode, 26: smoothing capacitor, 28: discharge resistor, 29: variable volume, 31: relay 13. 33: LED, A: display device.

Claims (1)

[Claims] A heat medium cycle having a compressor that compresses and discharges a heat medium, a power supply circuit that supplies power to the compressor, a voltage detection circuit that detects the power supply voltage of the power supply circuit, and an output signal of the voltage detection circuit that detects the and a control circuit for controlling the compressor.
The control circuit has a comparative determination function that compares the output value of the voltage detection circuit with a set value and outputs a signal to stop the compressor when the output value is lower than the set value. An air conditioner featuring: