JPH0719613A - Air conditioner - Google Patents

Abstract

PURPOSE:To ensure comfortable air conditioning control without having unnecessary waiting time upon restarting an air conditioner after interruption of the operation of the air conditioner. CONSTITUTION:When an overcurrent detector circuit 14 outputs an overcurrent signal, a timer 16 measures time since the time of starting of a compressor motor 5 to the time of detection of the overcurrent. When the measured time is less than 40 seconds, a first restarting control circuit 17 decides that a pressure difference between a high pressure side and a low pressure side is not so much greater, and immediately outputs a restarting instruction to a driver control circuit 15. In contrast, when the measured time exceeds 40 seconds, a second restarting control circuit 18 decides that the pressure difference between the low pressure side and the high pressure side gets greater, and outputs a restarting instruction to the driver control circuit 15 after the lapse of waiting time of two minutes and 20 seconds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a function of stopping the operation of a compressor motor when a motor overcurrent is detected.

[0002]

2. Description of the Related Art Most models of recent air conditioners are designed to drive a compressor motor at a variable speed via an inverter. And in such an air conditioner,
In order to protect the semiconductor elements inside the inverter, the operation of the compressor motor is stopped immediately when an overcurrent of the motor is detected.

On the other hand, if the compressor motor is temporarily stopped during operation, it is necessary to wait for a certain waiting time (for example, 2 minutes and 20 seconds) to elapse before restarting. This is to reliably prevent the compressor from being damaged by balancing the high pressure side and the low pressure side in the refrigerant circuit to some extent.

Therefore, even when the operation is stopped due to the protection operation based on the detection of the overcurrent of the compressor motor, the restart is uniformly prohibited within a fixed time.

[0005]

However, the above-mentioned waiting time when the restart of the compressor motor is prohibited is because the values on the high-pressure side and the low-pressure side, which have reached the level corresponding to the normal operating state, balance each other. It is set by considering it as necessary time.

On the other hand, the motor overcurrent may be detected in a short time after starting the compressor motor and the operation may be stopped. The cause of the motor overcurrent is the state of the sliding portion of the compressor drive mechanism. There are things due to subtle factors such as. In this case, if the operation is once stopped and then immediately restarted, then in many cases, the operation can be normally started smoothly.

Further, in this case, since the pressure difference between the high pressure side and the low pressure side is not so large, the compressor should not be damaged even if the compressor is immediately restarted.

Therefore, even if the operation is stopped by the protection operation based on the detection of the motor overcurrent,
Prohibiting the restart for a certain period of time not only delays the time it takes for the room temperature to reach the set value, but also increases the user's feeling of dryness. It was unfavorable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an air conditioner which eliminates unnecessary waiting time and performs more comfortable air conditioning control.

[0010]

As a means for solving the above-mentioned problems, the present invention operates the compressor motor when a compressor motor is driven at a variable speed by an AC output from an inverter and a motor overcurrent is detected. In the air conditioner to be stopped, overcurrent detection means for detecting the motor overcurrent, timer means for measuring the time from the start of the compressor motor, and at the time when the overcurrent detection means detects the overcurrent, When the measured time of the timer means is a predetermined time or less, a first restart control means that immediately outputs a restart command to the compressor motor, and a time point when the overcurrent detection means detects an overcurrent, When the time measured by the timer means exceeds a predetermined time, the compressor motor is operated after a preset waiting time has elapsed. A second restart control means for outputting a restart command, is characterized in that it comprises a.

[0011]

In the above structure, when the overcurrent detecting means detects the motor overcurrent, the timer means measures the time from the activation of the compressor motor to the detection of the overcurrent.

When the time measured by the timer means is less than the predetermined time, the first restart control means judges that the pressure difference between the high pressure side and the low pressure side is small, and does not wait for the waiting time. , Outputs a restart command immediately and restarts the compressor motor.

On the other hand, when the time measured by the timer means exceeds the predetermined time, the second restart control means judges that the pressure difference between the high pressure side and the low pressure side is large, and waits for the waiting time. After a lapse of, the restart command is output and the compressor motor is restarted.

[0014]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In FIG. 1, the AC power from the AC power supply 1 is converted into DC power by the converter unit 2, smoothed by the capacitor 3, and then converted into AC power again by the inverter unit 4. This AC power is supplied to the compressor motor 5, and the rotation of the compressor motor 5 drives the compressor 6.

The output of the inverter section 4 is subjected to variable voltage variable frequency control by the inverter control circuit 8 via the driver 7, whereby the compressor motor 5 is driven at a variable speed. A current detector 9 for detecting an overcurrent flowing through the compressor motor 5 is provided between the converter unit 2 and the inverter unit 4.

Explaining the refrigerant circuit, the refrigerant discharged from the compressor 6 is sent to the indoor heat exchanger 11 after passing through the four-way valve 10 in the heating mode. Then, the refrigerant that has undergone heat exchange in the indoor heat exchanger 11 is transferred to the expansion valve 1
After passing through 2 to the outdoor heat exchanger 13 where heat exchange is performed again, the heat is again circulated through the four-way valve 10 to the suction port of the compressor 6.

The inverter control circuit 8 is composed of a microcomputer, and as shown in the figure, an overcurrent detection circuit 14, a driver control circuit 15, a timer 16, a first restart control circuit 17, and a second restart. It has a control circuit 18 and the like.

Next, the operation of the present embodiment configured as described above will be described with reference to the flowchart of FIG.

The overcurrent detection circuit 14 constantly receives the detection signal from the current detector 9 and outputs an overcurrent signal when the detected value exceeds a set value. Now, assuming that the overcurrent detection circuit 14 detects an overcurrent during operation execution (steps 1 and 2), the driver control circuit 15
Controls the driver 7 based on the overcurrent signal from the overcurrent detection circuit 14 so as to stop the output of the signal. As a result, the transistor forming the inverter unit 4 is switched off, and the operation of the compressor motor 5 is stopped (step 3).

At this time, the overcurrent signal from the overcurrent detection circuit 14 is also sent to the second restart control circuit 18.
The second restart control circuit 18 determines whether the number of overcurrent detections is three or less (step 4).

In this case, since the overcurrent is detected for the first time, the determination in step 4 is YES, and the second restart control circuit 18 issues a command to prohibit restarting the compressor motor 5. It is output to the driver control circuit 15 (step 5).

On the other hand, the timer 16 includes the driver control circuit 1
5 and the signal input from the overcurrent detection circuit 14, the time from when the compressor motor 5 is activated to when the overcurrent is detected is measured.

Then, the first and second restart control circuits 1
7, 18 determines whether or not the measurement time of the timer 16 is 40 seconds or less (step 6), and if it is longer than 40 seconds, the second restart control circuit 18 makes the high-voltage side and the low-voltage side. Judging that the pressure difference between the two has become quite large, 2
After waiting for 20 minutes (step 7), the prohibition of restart is released (step 8), and a restart command signal is output (step 9). As a result, the driver control circuit 15 causes the inverter unit 4 to output AC power via the driver 7 and restarts the compressor motor 6.

However, when the measured time of the timer 16 is 40 seconds or less, the first restart control circuit 17 immediately determines that the pressure difference between the high pressure side and the low pressure side is not so large and immediately. Then, the prohibition of restart is released (step 8), and a restart command signal is output (step 9).

In this way, when the compressor motor 5 is restarted and the operation is restarted (step 1), the detection of overcurrent is caused by the condition of the subtle sliding portion of the compressor 6 and the like. If so, the restart will continue stable operation.

However, if an overcurrent is generated due to a failure of the compressor motor 5 or the compressor 6 itself, an overload, or the like, the motor overcurrent is immediately detected even if the above restart is performed. (Step 2), the operation will be stopped.

The determination of the number of times of detection performed in step 4 takes such a case into consideration. That is,
The second restart control circuit 18 outputs a total stop command and an abnormality display command to prevent unnecessary restart when the number of overcurrent detections exceeds three (step 1).
0). As a result, not only the compressor motor 5 but also all the equipment such as the outdoor fan and the indoor fan are stopped, and the abnormality is displayed on the display provided in the indoor unit.

By the way, in the recent inverter section, IP
There is an M (Intelligent Power Module), that is, one having a short-circuit current protection function. This can be considered that the inverter unit 4 in FIG. 1 incorporates the current detector 9, the overcurrent detector 14, and other circuits, and when a motor overcurrent occurs, the inverter unit 4 itself. The function automatically turns off the transistor to stop the operation.

The present invention is also applicable to an air conditioner using such an IPM built-in inverter unit, but the configuration of FIG. 1 in that case omits the current detector 9 and the overcurrent detection circuit 14. It will be what you did.

[0031]

As described above, according to the present invention, when the overcurrent is detected shortly after the start and the operation is stopped, the restart is immediately started without waiting for the elapse of a certain waiting time. Since the configuration is performed, unnecessary waiting time can be eliminated and comfortable air conditioning control can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of FIG.

[Explanation of symbols]

 4 Inverter section 5 Compressor motor 6 Compressor 8 Inverter control circuit 9 Current detector 14 Overcurrent detection circuit 15 Driver control circuit 16 Timer 17 First restart control circuit 18 Second restart control circuit

Claims (2)

[Claims] 1. An air conditioner that drives a compressor motor at a variable speed by an AC output from an inverter and stops the operation of the compressor when a motor overcurrent is detected. Means, timer means for measuring the time from the start of the compressor motor, and at the time when the overcurrent detection means detects an overcurrent, immediately when the measurement time of the timer means is less than or equal to a predetermined time. First restart control means for outputting a restart command to the compressor motor, and when the overcurrent detection means detects an overcurrent, if the measurement time of the timer means exceeds a predetermined time, Second restart control means for outputting a restart command to the compressor motor after a set waiting time has elapsed, Air conditioner according to claim. 2. The air conditioner according to claim 1, wherein the predetermined time is 40 seconds.