JPS5919232Y2 - Air conditioner control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air conditioner control device that detects indoor and outdoor temperatures and controls a compressor motor.

This type of air conditioner has both a function to detect the temperature difference between indoor and outdoor and a function to compare the indoor temperature with the set value. Some devices are configured to operate the compressor motor when the temperature is higher than the room temperature, thereby lowering the indoor temperature.

This is because if the operation of the compressor motor is controlled regardless of the temperature difference between indoors and outdoors, for example, even when the outdoor temperature is very high and the temperature difference between indoors and outdoors is large, the room may be cooled, and the temperature difference becomes even more This is to eliminate problems such as discomfort and air conditioning sickness due to sudden changes in temperature when a person enters a room from outside.

Conventionally, there is a control device for this type of air conditioner as shown in FIG.

A pair of power transmission cables 5 are connected to a common contact point of a relay contact 4 to which the indoor temperature sensing element 1 is connected and which switches between a temperature measurement circuit 2 equipped with a DC power supply for low voltage supply and a commercial AC power supply 3 for high voltage supply. is connected.

A compressor motor 7 , an outdoor temperature detection element 8 , and a relay coil 9 are connected in parallel to the outdoor side of the cable 5 . Switch and connect.

Here, when the relay contact 6 is connected to the motor 7 side, it is turned on, and when it is connected to the temperature detection element 8 side, it is turned off.

After the relay contact 4 is switched to the temperature measuring circuit 2 side, the DC power is applied to the temperature measuring circuit 2, and signals from the temperature detecting elements 1 and 8, which detect indoor and outdoor temperatures, are input. Relay coil 10 that switches and operates relay contact 4
A controller 11 is connected to the controller 11 for giving signals to the controller.

In the control circuit of the air conditioner having such a configuration, when the relay contact 4 is switched from the commercial AC power supply 3 to the temperature measurement circuit 2 side equipped with a low voltage DC power supply, that is, when a low voltage is applied to the relay coil 9, the relay contact 6 is turned off, temperature measuring circuit 2
and the temperature sensing elements 1 and 8 form a closed circuit to monitor indoor and outdoor temperatures.

However, since the low voltage of the DC power supply is also applied to the relay coil 9 when monitoring the indoor and outdoor temperatures, the signal from the detection element 8 is affected by the impedance change of the relay coil 9 due to changes in the outdoor temperature. As a result, the outdoor temperature could not be measured accurately and the control performance was poor.

The present invention was developed in view of the above points, and the relay coil for turning on/off the first switch means for supplying/cutting off the excitation current to the compressor motor and the indoor/temperature rise detection element are connected to one another. The above-mentioned drawbacks of the conventional relay coil are solved by providing a cut-off means for cutting off the current to the relay coil when the low voltage is applied to the parallel circuit consisting of the relay coil.

Hereinafter, one embodiment of the present invention will be described based on FIG. 2.

21 is a control unit built into the indoor main body of the indoor/outdoor separated air conditioner, 22 is a control unit built into the outdoor main body of the air conditioner, and 23 connects the control units 21 and 22. Power transmission cable (hereinafter referred to as cable).

), 24 is a commercial AC power source as a high-voltage power source, 25 is a compressor electric motor built into the outdoor main body, 26 is an outdoor temperature detection element such as a thermistor, and 27 is a cable 2.
3 as a common contact, and 28 is a relay contact as a first switch means for switching energization to the motor 25 side when on and to the outdoor temperature sensing element 26 side when off; 28 is a protection connected in series to the outdoor temperature sensing element 26. Resistor, 29 is outdoor temperature sensing element 2
A bidirectional constant voltage diode is connected in parallel to the sensing element 26 as an overvoltage prevention device that bypasses the current to the sensing element 26 at a predetermined voltage so that an excessive current does not flow through the sensing element 6 .

30 is a relay coil that is interposed between the cables 23 and turns on the relay contact 27 when the high voltage of the commercial AC power supply is applied, and turns off the relay contact 27 when the low voltage of the DC power supply is applied, and is parallel to the detection element 26 and the motor 25. It is connected to the.

31 is when the relay contact 27 is off, that is, the relay coil 30
When the low voltage is applied to the parallel circuit consisting of the and outdoor temperature sensing element 26, a capacitor 32 is connected in series to the relay coil 30 as a interrupting means to interrupt the current to the relay coil 30, and 32 is a thermistor or the like. A temperature detection element 33 is interposed between the cable 23 and a relay coil 30
A relay contact is used as a second switch means to selectively apply the commercial AC power source 24 and the DC power source to the commercial AC power source 24 side when on and to the DC power source side when off.

Numeral 34 is a temperature measurement circuit that receives signals from the detection elements 26 and 32 to measure indoor and outdoor temperatures, and is equipped with a low-voltage DC power source that serves as the low-voltage power source.

A relay contact 35 serves as a changeover switch that selectively supplies the low DC voltage to the indoor temperature detection element 32, and is interposed between the low voltage power supply and the relay contact 33, and is connected to the relay contact 33 side when on, and indicates the indoor temperature when off. Switching to the detection element 32 side.

36 is connected to the output of the temperature measuring circuit y, and compares the set indoor temperature with the indoor temperature, and also the difference between the indoor temperature and the outdoor temperature with a predetermined temperature difference, and outputs a signal to turn on/off the relay contacts 33 and 35. A control circuit 37 is a temperature setting volume for adjusting the indoor set temperature of the control circuit 36, and when the difference between the outdoor temperature and the indoor temperature exceeds the predetermined temperature difference, the indoor set temperature is changed to a new higher indoor temperature by the control circuit 36. The set temperature is selected.

38 is a relay coil that turns on and off the relay contact 33 in response to an output signal from the control circuit 36; 39 is a relay coil that turns on and off the relay contact 35 in response to an output signal from the control circuit 36, and the relay contact 33 is turned off. In other words, when a high residual voltage remains in the compressor motor 25, the relay is activated after a predetermined delay to prevent the residual voltage from being applied to the temperature measuring circuit 34 etc. and damaging the measuring circuit 34 etc. Turn on contact 35.

Next, the action will be explained.

For example, if the indoor temperature is higher than the set indoor temperature and the difference between the indoor temperature and the outdoor temperature is less than a predetermined temperature difference, the control circuit 36 gives signals to the relay coils 38 and 39, respectively,
Relay contact 33 is turned on and relay contact 35 is turned off.

When the relay contact 33 is turned on, the high voltage of the commercial AC power supply 24 is applied to the relay coil 30, the relay contact 27 is turned on, and the compressor motor 25 is excited to perform cooling operation.

On the other hand, since the relay contact 35 is in the OFF state, the indoor temperature sensing element 32 is connected to the temperature measuring circuit 34 and monitors the indoor temperature.

Note that even if the relay contact 33 is turned on at this time, the selector switch 27 remains off for a short time due to the delay of the relay coil 30, and the high voltage of the commercial AC power supply 24 is applied to the outdoor temperature detection element 26. However, the sensing element 26
Since the bidirectional voltage regulating diode 29 is connected in parallel with the detecting element 26, a high voltage is not applied to the detecting element 26 and the detecting element 26 is not damaged.

In addition, since it is bidirectional, the indoor/outdoor control unit 21.
When connecting 22, there is no problem even if the polarity is wrong.

The cooling operation continues and the indoor temperature is set at temperature setting volume 37.
When the indoor temperature falls below the set indoor temperature, the control circuit 36
is determined, and signals are given to the relay coils 38 and 39 respectively, the relay contact 33 is turned off and the relay contact 35 is turned on, and the high voltage supply to the compressor motor 25 is cut off.

At this time, even if relay contact 33 is turned off, relay contact 27
does not turn off immediately, and the relay contact 27 remains on for a short time due to the time delay of the J sea coil 30, and there is a risk that the residual voltage of the motor 25 will be applied to the temperature measurement circuit 34, etc., but the changeover switch 35 Since it is configured to turn on after a predetermined period of time has elapsed, the residual voltage decreases during that time, so that no high voltage is applied to the temperature measurement circuit 34, etc., and there is no fear of damage.

Then, the relay contact 35 is in the on state and the relay contact 27 is in the on state.
, 35 are turned off, the temperature measurement circuit 3 is connected to the parallel circuit consisting of the relay coil 30 and the outdoor temperature detection element 26, etc.
The low voltage of the DC power supply No. 4 will be applied, and the outdoor temperature will be monitored.

At this time, since the relay coil 30 is connected in series with a capacitor 31 that blocks the DC component, no current flows through the relay coil 30.

Therefore, even if the impedance of the relay coil 30 changes due to the outdoor temperature, it will not affect the signal from the outdoor temperature detection element 26, so the outdoor temperature can be accurately measured, and the performance of the control device can be improved. I can do it.

Further, during cooling operation, if the difference between the indoor temperature and the outdoor temperature reaches a predetermined temperature difference even though the indoor temperature is higher than the indoor set temperature, the control circuit 36 finally adjusts the indoor temperature corresponding to the signal. It is determined that the difference with the measured outdoor temperature has reached a predetermined temperature difference, and a signal is output to the relay coils 38 and 39, respectively.

As a result, the relay contacts 33, 35 are switched in the same manner as above, the high voltage supply to the compressor motor 25 is cut off, the cooling operation is stopped, and the outdoor temperature is accurately detected by the outdoor temperature detection element 26 in the same manner as above. .

Then, the signal from the detection element 26 is sent to the temperature measurement circuit 34.
The control circuit 36 automatically sets a new indoor temperature setting by adding a certain value (for example, 1° C.) to the indoor temperature setting.

In the example, a capacitor was used to cut off the current to the relay coil when a DC power supply voltage was applied to the parallel circuit between the outdoor temperature sensing element and the relay coil, but it is also possible to connect a bidirectional thyristor or the like to the relay coil. It's okay.

Further, although the protective bidirectional diode is connected in parallel to the outdoor temperature sensing element, a diode that allows current to flow in one direction may be connected with consideration to polarity.

Further, these devices may be provided in an indoor temperature sensing element or a component portion that may be damaged by transient application of high voltage.

Although a relay contact is used as the switching means, it goes without saying that a semiconductor analog switch may also be used.

Furthermore, it goes without saying that the present invention can be applied not only to an outdoor temperature sensing element and a relay coil connected in parallel, but also to an indoor temperature sensing element and a relay coil connected in parallel.

As explained above, according to the present invention, the first switch means for supplying and interrupting the excitation current to the compressor motor is made up of a parallel relay coil and a temperature detection element that are switched on and off by switching between high voltage and low voltage. Since the circuit is provided with a cutoff means that cuts off the current to the relay coil when a low voltage that turns off the first switch means is applied to the circuit, when the temperature is detected by the temperature detection element, the Since a change in the impedance of the relay coil due to a change in temperature does not change the influence on the signal from the temperature sensing element, accurate temperature measurement can be performed and control performance can be greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a control system for a conventional indoor/outdoor air conditioner, and FIG. 2 is a diagram of a control system for the above-mentioned air conditioner, which is an embodiment of the present invention. 24...Commercial AC power supply, 25...Compressor motor, 26...Outdoor temperature detection element, 27
...Relay contact, 30...Relay coil, 31...Capacitor, 32...
Indoor temperature detection element, 33... Relay contact, 34
...Temperature measurement circuit, 36...Control circuit, 38...Relay coil.

Claims (5)

[Scope of utility model registration request] (1) A compressor electric motor and an excitation current applied to the electric motor.
a first switch means for shutting off; and a first switch means for turning on and off the switch means;
a relay coil to be turned off; a second switch means for selectively applying a high voltage for turning on the switch means and a low voltage for turning off the switch means to the relay coil; an indoor temperature sensing element; and an outdoor temperature sensing element. In the air conditioner control device, the air conditioner control device includes a control circuit that detects an indoor temperature rise based on a signal from the controller and controls the second switch means, and one of the detection elements and the relay coil are connected in parallel. A control device for an air conditioner, characterized in that the air conditioner control device is provided with a cutoff means for cutting off current to the relay coil when the low voltage is applied to a parallel circuit consisting of either one of the temperature detection elements and a relay coil. (2) The air conditioner control device according to claim 1, wherein the low voltage is a DC low voltage, and the cutoff means is a capacitor connected in series to the relay coil. (3) The temperature sensing element connected in parallel to the relay coil is provided with an overvoltage prevention means so that a voltage exceeding a predetermined value is not applied.
A control device for an air conditioner as described in Section 1. (4) The air conditioner control device according to claim 3, wherein the overvoltage prevention means is a bidirectional constant voltage diode connected in parallel to the detection element. (5) The temperature sensing element that is not connected in parallel with the relay coil is connected in parallel to the power source via a changeover switch interposed between the power source that supplies the low voltage and the second switch means, and The changeover switch is configured such that after a predetermined period of time has passed after the second switch means has been switched from the high voltage side to the low voltage side in response to a signal from the control circuit, the changeover switch is switched from the sensing element to the second switch means side. A control device for an air conditioner according to any one of claims 1 to 4, which is registered as a utility model.