JPS6262147A - Control device for air-conditioning machine - Google Patents

Abstract

PURPOSE:To prevent the trouble of a compressor by a method wherein the compressor is stopped when the value of the operating electric current of the compressor exceeds a specified medium electric current once and falls under a specified condition. CONSTITUTION:The control device for this air-conditioning machine turns an outdoor fan OFF until the value I of detecting electric current exceeds a specified large electric current I1 and the same value becomes smaller than a specified small electric current I3 when the value I of detecting electric current has exceeded a specified medium electric current I2. When the detecting value I does not become smaller than the specified small electric current I3 or higher than the specified large electric current I1 after a specified time A (3min for example) has elapsed and the operation of a compressor has been continued with the outdoor fan stopped, the compressor is also stopped. When the condition of a room temperature thermostat changes to turn ON the compressor after 3min, the compressor is re-started. In this case, the outdoor fan is also operated. When this stop-and-operation cycle is repeated a specified number of times B (twice), the repetition is considered to be due to the defficiency of a func tional part of a current detecting circuit and all of the operation is stopped. The compressor may be protected from breakage in such manner.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a control device for protecting a compressor of an air conditioner such as a heat pump type.

Conventional technology> Conventionally, heat pump air conditioners have been provided with a current sensing circuit that senses the operating current flowing through the compressor motor during heating, as shown in Figure 3, and the sensed current value of the current sensing circuit is If the current increases to the specified medium current 12 or more, the evaporator side blower fan is stopped (OFF), and when the sensed current value I increases to the specified large current 11 or more, the compressor is stopped (OFF), and the sensed current value I
A microcomputer-made control circuit ICI is provided which rotates (ON) the evaporator side blower fan when the specified small current II decreases to a specified small current 13 or less, and the specified large current II > the specified medium current I2.
>The specified small current I3 is set.

The electric motor of the evaporator side blower fan, that is, the outdoor fan, is controlled as follows.

(a) Keep the outdoor fan at H (high speed rotation) until the sensed current value ■ exceeds the specified small current I3.

(b) When the sensed current value I exceeds the specified small current I3, the outdoor fan is kept at L (low speed rotation) until the wind speed switching current falls below 14 and until the specified medium current exceeds 2.

(c) If the detected current value ■ exceeds the specified small current ■3 but falls below the wind speed switching current 14, the outdoor fan is kept at H.

(d) When the sensed current value I exceeds the specified medium current I2, the outdoor fan is turned off until it exceeds the specified large current (1) and until it becomes below the specified small current I3.

(e) If the detected current value I exceeds the specified heavy snow;
Turn off the outdoor fan and turn off the compressor.

Once the compressor is stopped, it will pause for 3 minutes.
It cannot be restarted during these 3 minutes. After 3 minutes, if the room temperature thermostat conditions are such that the compressor is turned on, the compressor will be restarted.

However, in order to prevent malfunction due to the starting current when the compressor is turned on, f-11 is cut off as the wind speed switching current is 14 or less for 5 seconds after the compressor is turned on.

Next, the conventional current sensing circuit and control circuit will be explained based on FIG. 4.The current sensing circuit consists of a current transformer C
The operating current of the compressor is detected by the current transformer CT as a sensed current value ■, and when it exceeds the set value, the comparator IC6 outputs an H level signal to the control circuit ICI. is configured to do so. Therefore, a voltage proportional to the compressor motor current is induced in the current lance CT, which is half-wave rectified by diode D5 and smoothed by capacitor C8. Then, the voltage divided and adjusted by the resistors R5 and R8 and the semi-fixed resistor VR is applied to the positive input terminal (No. 3 bin) of the comparator c6. In addition, the negative input terminal (No, 2nd pin)
In order to determine which zone the voltage at the positive input terminal is in, four types of voltages are intermittently applied from the control circuit, and their waveforms are as shown in FIG.

For example, if 1.60V is applied to the positive input terminal, and 1.51V is applied to the negative input terminal, the Hunhalator IC
The output of 6 becomes <H level as shown in Figure 6, and the negative input terminal is 1.6? When V, the output of comparator IC6 is L.
level, and it can be determined whether the sensed current value (operating current) is in the current zone between the wind speed switching current I4 (12A) and the specified small current 13 (13A).

In the above control device, if the detected current value ■ stagnates between the specified medium current I2 and the specified large current 1 due to a defect in the current sensing function of the current sensing circuit, the outdoor fan will stop. As a result, the compressor continues to operate for heating, and the outdoor heat converter (evaporator) does not evaporate sufficiently, and the refrigerant liquid is compressed by the compressor, which causes the compressor's circulating oil to This can lead to dilution and this condition can last for a long time, and in the worst case scenario, the compressor motor may lock up.

Normally, the operating current is detected by a current sensing circuit, and if the current becomes excessive and the compressor is overloaded, the evaporator side blower fan (outdoor fan) on the outdoor heat exchanger side is stopped.
One misstep in an attempt to lighten the compressor load on the cycle can destroy an expensive compressor due to a faulty inexpensive component in the current sensing circuit.

<Purpose> In view of the above, the present invention provides a control device that performs overload control of an air conditioner. The object of the present invention is to provide a control device for an air conditioner that prevents an expensive compressor from malfunctioning due to the compressor being operated for a long period of time while stopped (OFF).

<Examples> Examples of the present invention will be described in detail below. First, to explain the first embodiment, a current sensing circuit is provided to sense the operating current flowing through the motor of the compressor. The device side ventilation fan (corresponds to the outdoor fan during heating operation of the heat pump type air conditioner and the indoor fan during cooling operation) is stopped (OFF), and the sensed electric current; light value ■ increases to a specified large current of 11 or more. Then, a microcomputer-made control circuit ICI is provided which stops the compressor (OFF) and turns on (ON) the evaporator side blower fan when the sensed current value (■) decreases to a specified small current of 13 or less. 11〉Specified medium current I
2> Specified small current ■ In the control device of the air conditioner set to 3, the control circuit is configured to, for example, detect the sensed current value once the sensed current value ■ exceeds the specified medium current I2 and meets the specified condition. When ■ once exceeds the specified medium current I2, and then the state between the specified large current ■1 and the specified small current 13 (the state where the evaporator side blower fan is stopped and the compressor is running (ON)) continues for the specified time l\ This has an added function to stop the compressor even if the detected current value ■ is less than the specified large current 11.

The present invention will be explained with reference to the 70-chart of the control circuit in FIG. 1. For example, during heating operation, the control is performed as follows.

[1] In addition to items (a) to (e) of the conventional control device, the following [
Add items 2] to [6].

[2] When the sensed current value ■ exceeds the specified medium current 12, the timer TMI is counted, and even if the specified time A (for example, 3 minutes) has passed, the specified small current 13 or less, or the specified large current ii1
If the value does not exceed 1 and the compressor continues to operate with the outdoor fan stopped, the compressor is stopped and the counter C is set to +1.

[3] After the compressor stops (3 minutes),
That is, when the delay timer TM2 is cleared, the compressor is operated when the room temperature falls below the set value and the room temperature thermostat causes the compressor to be restarted (ON).

[4] If the sensed current value I does not fall below the specified small current I3, the outdoor fan will remain stopped.

[5] If items (2) and (3) are repeated, all operations will be stopped if the specified number of times B (2 times) is repeated.

[6] If the sensed current value I falls below the specified small current 13 even once, the counter C is cleared to 0.

In addition, in the flowchart, the H and L of the evaporator side ventilation fan are determined by the specified small current (■3) and the wind speed switching current (■4) line.
Although the control is omitted, in this embodiment, control is performed in the same manner as in the conventional control device.

Normally, when the above control is performed, the sensed current value ■ increases for some reason, and the specified current T -)
Circle Lj-ner n ”#Il't M '7
'-L, l-wh L Shizu2 (
The heat exchange rate of the heat exchanger (evaporator) decreases, the compression (work) of the compressor decreases, and the sensed current value decreases, becoming less than the specified small current of 13, and the outdoor fan also operates. i1g.

Even so, when an overload occurs due to the operating environment of the air conditioner, the conventional control device continues to operate the compressor while the outdoor fan is stopped, which may result in the compressor being destroyed as described in 111j.

In the present invention, as in item [2], the compressor is stopped once after a maximum specified time of A minutes. In this way, when the compressor is stopped, the sensed current value (operating current) decreases, and the next time the compressor is started,
The outdoor fan also rotates.

Repeating the specified number of times as described in item [5] is obviously abnormal, so stop the operation and protect the compressor from destruction. Note that the indoor fan heats the room only when the compressor is operating.

Further, since most of the operating current of the air conditioner is current flowing through the compressor, the current flowing through the compressor is approximately equal to the operating current of the air conditioner.

Because excessive current may flow temporarily when the compressor is started, etc., the sensed current value ■ will not exceed that value (for example, specified medium current ■2, specified small current ■3, etc.) even after 5 seconds have passed. Determine by

Next, a second embodiment of the present invention will be described based on FIG. When the air conditioner is heating, the detected current value ■ exceeds the specified medium current l2 (14A), the outdoor fan is stopped, and even after the specified time A has passed, the specified small current l3 (13A> or less) Under conditions where the current does not exceed 1 (15A), the following are possible causes: (a): The air conditioner's current sensing circuit is defective; and (b): actual overload operation.

However, in the first embodiment, the compressor is immediately stopped under the above conditions, and if the room temperature thermostat is on after the stop time (3 minutes), the compressor is turned on again.

In the case of cause (a), the same as in the first embodiment may be used, but in the case of cause (1), the compressor is stopped, the sensed current value r decreases, and the force and Kunter C are cleared repeatedly. It will never happen twice. Therefore, in the case of overload operation due to unfavorable conditions, the compressor will be turned off repeatedly.

This is effective from the perspective of protecting the compressor, but from the user's perspective, if the compressor stops immediately due to a slight overload, it means that the heating will repeatedly turn off immediately when you want it. In some respects, this is causing inconvenience.

However, in the second embodiment, the specified condition of the control circuit is that even if the evaporator side blower fan is stopped for a specified period of time A, the detected current is between the specified large current 11 and the specified small current I3. In this state, the evaporator-side blower fan is rotated specially, and the evaporator-side blower fan is rotated a specified number of times B.

That is, the control circuit is given the following functions.

[1] When the sensed current value (■) of the compressor's current sensing circuit exceeds the specified medium current 12 (14A), the outdoor fan is stopped.

[2] Even after the outdoor fan is stopped and the specified time A (3 minutes) has elapsed, the sensed current value I does not fall below the specified small current l3 (13A), and the specified large current ■1 (15A) or more If it does not, it is assumed that the detected current value (■) exceeds the specified low current l3 (13A), and the outdoor fan is specially operated at L (low speed rotation).

[3] Again, the sensed current value I increases, and the specified current l
2 (14A), the outdoor fan is stopped as in [1].

[4] When (1)-[2] NO OUTDOOR 77 NO ON-OFF is repeated the specified number of times B (10 times), the operation of the air conditioner is stopped.

However, when the sensed current value (■) falls to the specified small current I3, the specified number of times B is cleared and the counter C is returned to O.

The functions 1) added to the control circuit of the second embodiment are as follows. That is, during heating, when the temperature sensor that detects the temperature of the indoor heat exchanger detects the first specified temperature during heating operation, the indoor temperature changes slightly from the first specified temperature until it senses the second specified temperature. The outdoor fan for blowing air to the heat exchanger is stopped, and the operation of the air conditioner is stopped when the outdoor fan falls under the following conditions. If the temperature does not fall below the temperature detected by the temperature sensor or a second specified temperature, the detected temperature is deemed to have exceeded the second specified temperature due to a rise in temperature, and the conditions for special rotation of the outdoor fan, and the number of special rotations of the outdoor fan. The condition is that the number of times reaches a specified number of times. That is, in this embodiment, the temperature of the indoor heat exchanger is sensed by a temperature sensor, and when the temperature becomes higher than a specified value, the outdoor fan is stopped, and the outdoor fan is stopped by the sensed current value I of the compressor. During the operation, an outdoor fan stop signal is generated by the control circuit to turn on the outdoor fan for a specified time A minutes due to high temperature. At that time, counter C counts as one time, and under no circumstances should the compressor be turned on for more than the specified time A (3 minutes) with the outdoor fan turned off.

In addition, the counter C adds up the number of times based on the temperature of the indoor heat exchanger and the number of times based on the sensed current value I, and calculates the specified number of times B (
(10 times) or more, stop the operation of the air conditioner.

<Effects> As is clear from the above description, the present invention is provided with a current sensing circuit that senses the operating current flowing through the motor of the compressor, and when the sensed current value of the current sensing circuit increases beyond the specified current, evaporation occurs. Control that stops the evaporator side blower fan, stops the compressor when the sensed current value increases to a specified large current or more, and rotates the evaporator side blower fan when the sensed current value decreases to a specified small current or less. In a control device for an air conditioner in which a circuit is provided and the relationship is set to a specified large current > specified medium current > specified small current, 11
1. The control circuit has a sensing type l! when the sensed current value exceeds the specified current once and meets the specified condition. This invention relates to a control device for an air conditioner, characterized in that it has an additional function of stopping the compressor even if the current value is less than a specified large current.

Once upon a time, according to the present invention, an inexpensive current sensing circuit for a compressor fi! This has an excellent effect of preventing the expensive compressor from breaking down due to the compressor being operated for a long time with the evaporator side blower fan stopped due to a defective part.

[Brief explanation of drawings]

FIG. 1 is a flowchart of the control circuit in the first embodiment of the control device of the present invention, FIG. 2 is a flowchart of the control circuit in the second embodiment, and FIG. 3 is a diagram for explaining the operation of the conventional control device. FIG. 4 is an electronic circuit diagram of the current sensing circuit of the compressor, and FIGS. 5 and 6 are diagrams for explaining the operation of the current sensing circuit. ■: Sensing current value, 11: Specified large current, I2: Specified medium current, ■3: Specified small current, A: Specified time, C: Calantar,
TM1: Timer, TM2: Delay timer, IC
I: control circuit, CT: current transformer, IC6: comparator.

Claims (3)

[Claims] (1) A current sensing circuit is provided to sense the operating current flowing through the motor of the compressor, and if the sensed current value of the current sensing circuit increases to a specified medium current or higher, the evaporator side blower fan is stopped, and the sensed current A control circuit is provided which stops the compressor when the sensed current value increases above a specified large current, and rotates the evaporator side blower fan when the sensed current value decreases below a specified small current. >In an air conditioner control device that is set to a specified small current relationship, the control circuit is configured such that when the sensed current value exceeds the specified medium current once and meets the specified condition, the sensed current value becomes the specified large current. A control device for an air conditioner, characterized in that it has an added function of stopping a compressor even if the air pressure is lower than that. (2) The specified condition is a condition in which the sensed current value exceeds the specified medium current once, and then the state between the specified large current and the specified small current continues for a specified period of time. ) A control device for an air conditioner as described in item 2. (3) The specified condition is that even if the evaporator side blower fan is stopped for a specified time, if the sensed current value is between the specified large current and specified small current, the evaporator side blower fan is The control device for an air conditioner according to claim (1), characterized by comprising a condition that the evaporator-side blower fan rotates to a specified number of times, and a condition that the number of special rotations of the evaporator-side blowing fan reaches a predetermined number of times.