JPS59191838A - Control method of compressor of air conditioner - Google Patents

Abstract

PURPOSE:To reduce aggregate input by preventing mallubrication of a sliding part from occurring, protecting a compressor and controlling suspension frequency of the compressor, by a method wherein the compressor is suspended after running the compressor continuously for more than a fixed period of time at frequency less than common frequency under overloading terms of heating. CONSTITUTION:A refrigeration cycle is constituted with an indoor side heat exchanger 8, an outdoor side heat exchanger 9, a compressor 10 and an expansion valve 11. Checking in relation to establishment of a room temperature is made by taking a signal of a temperature sensor 12 of the indoor side heat exchanger 8 in a frequency control part 13. When a temperature, namely, sensed by the temperature sensor 12 is higher than a room temperature under overloading terms of heating, a signal K whose frequency has been reduced is applied to the frequency control part 13. Sensing is kept on at regular intervals. With this construction, a frequency converting part 14 received a signal L reduces the frequency to a minimum. Then a pressure switch 16 is operated through pressure of the heat exchanger 8 and an operation signal P is being kept signaled so long as the pressure does not become less than a predetermined value.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a compressor control method for a heat pump air conditioner in which the rotation speed of the compressor is controlled by frequency conversion control according to the air conditioning load. .

The structure and problems of the conventional example The structure and problems of the conventional example will be explained with reference to FIGS. 1 to 3. A variable capacity air conditioner that uses the generally known frequency conversion method to control the compressor rotation speed changes the compressor rotation speed by converting the frequency of the compressor power supply, and sets the compressor rotation speed quickly at the start-up stage. It allows the indoor unit to reach room temperature and supplies the required capacity at the temperature setting of the indoor unit at an appropriate rotation speed.

In Fig. 1, the frequency at which high-speed rotation is performed is BHz.

The frequency that performs rotation corresponding to the set room temperature A is CHZ~DH
It is z. As a result, the required air conditioning conditions can be reached more quickly, and an air conditioning condition with the minimum supply capacity can be obtained. Note that 8 indicates the set room temperature.

FIG. 2 shows an example of compressor operation control for the set room temperature using the frequency conversion method. In the case of a normal compressor whose capacity cannot be varied by frequency conversion, control using a thermostat will prevent the indoor temperature from falling below (cooling) or rising above the set value. (heating), the compressor is stopped and the compressor is restarted when the room temperature returns to the set value. A large amount of electricity is consumed during the process.

On the other hand, in indoor temperature control using a compressor whose rotation speed can be freely changed by frequency conversion control, if the temperature falls below the set value by a certain range α or β (cooling) or exceeds the set value ( (heating), by lowering the frequency of the compressor, the rotational speed of the compressor is reduced, the supply capacity is reduced, and the room temperature is controlled to the set temperature, thereby eliminating the need for electricity from stopping the compressor to stabilizing restart. The indoor temperature can be maintained at the set value. Note that the operating frequencies of the compressor are shown in E to H in the figure.

Due to the above advantages, overall power consumption can be reduced and required air conditioning conditions can be maintained.

Here, the compressor rotational speed changes due to changes in indoor heat load and outside air conditions, and since the rotation speed is wide, problems arise from the lubrication side of the compressor. Next, FIG. 3 shows the configuration of the compressor drive of a conventional air conditioner, and its problems will be described.

In FIG. 3, an electric motor 2. A compression element 3 and lubricating oil 4 are housed therein, and an oil pump 6 provided below a rotary shaft 5 forming the center of the compression element 3 supplies the lubricating oil 4 to the @ section. The refrigerant compressed by the compression element 3 is discharged into the lower space M of the electric motor 2, passes through the gap N between the electric motor 2 and the outer shell 1, moves to the upper space of the electric motor 2, and is provided in the second part of the outer shell 1. It is sent out to the outside through the entire piping 7.

The lubricating oil 4 is supplied by an oil pump 6 provided on the rotating shaft 6. The lubricating oil supplying capacity of the oil pump 6 changes depending on the rotational speed of the rotating shaft 6, and as the rotational speed decreases, the lubricating oil 2 is supplied. supply capacity will decline. Conversely, as the rotational speed increases, the lubricating oil 4 supply capacity also increases.

Here, in a compressor used in an air conditioner that controls room temperature using frequency conversion control, at low rotational speeds, sliding parts (not shown) that require lubricant supply from the oil pump 6 run out of lubricating oil. , burn-in is more likely to occur.

OBJECTS OF THE INVENTION The present invention aims to improve compressor control by frequency conversion control, maintain the lubrication performance of the compressor, and protect the compressor.

Composition of the Invention The present invention provides a method for reducing the frequency when the frequency output from the compressor operating frequency control section of an air conditioner is a low frequency outside the normal frequency range.
If the compressor is operated continuously for a certain period of time with the indoor pressure detector operating, the compressor will be completely stopped.

DESCRIPTION OF EMBODIMENTS The present invention will be described below with reference to FIG. 4 of the accompanying drawings showing one embodiment thereof.

In FIG. 4, indoor heat exchanger 8. Outdoor heat exchanger 9
．． Compressor 10. The expansion valve 11 constitutes a refrigeration cycle. A temperature sensor 12 is disposed in the indoor heat exchanger 8, and a temperature signal detected by the sensor 12 is inputted to a frequency control section 13, and an arbitrary signal set by an operation section (not shown) of the indoor unit is inputted into the frequency control section 13. Check the room temperature settings. A frequency conversion unit 14 controlled by the frequency control unit 13 converts the general commercial power input from the power supply 15 into the required frequency power, and applies it to the compressor 10, thereby converting it according to the indoor heat load. Drive.

When performing heating operation, if the compressor 10 is operated with the set temperature of the indoor unit low, the frequency control section 13 sends a signal to the frequency conversion section 14 to lower the frequency, and the compressor 10 is operated at the minimum temperature. The entire operation is performed at the same rotation speed, and this state is maintained.

As mentioned in the conventional example, this situation is bad for the lubrication of the compressor 10, so if it continues for a certain period of time, it is necessary to increase the rotation speed to a slightly higher speed to circulate the lubricating oil sufficiently. need to be added.

Here, a frequency that gives a slightly higher rotational speed is defined as a common frequency.

In addition, the indoor heat exchanger 8 disposed in the indoor unit is equipped with a pressure switch that regulates the pressure rise to protect the compressor 1o and the indoor heat exchanger 9 when the pressure rise during heating becomes large. There are 16. When the pressure gas isolator 16 operates, the frequency control section 13 needs to perform control to prohibit the frequency from increasing.

During heating operation, the set temperature of the indoor unit is low and the outside air temperature is high, which is a so-called heating overload condition.

In the present invention, a temperature sensor 12 detects the temperature of warm air blown out from an indoor unit under a heating overload condition, and if the temperature is higher than the room temperature set by the indoor unit, a frequency range signal is sent to a frequency control unit 13. K is sent, and thereafter it continues to detect and transmit at regular intervals. Frequency control unit 1 receiving frequency range signal Ki
3) A command signal in the frequency range is transmitted to the frequency converter 14, and the frequency converter 14 receives this signal and lowers the frequency to the lowest frequency.

The pressure gas isolator 16 provided in the device 8 operates when the set value is all set, and transmits an operation signal P to the frequency control unit 13.
The transmission continues as long as the pressure does not fall below the set value of the compressor protector 16. If this state continues and the lowest frequency continues for a certain period of time as described above, an f-word to slightly increase the frequency is transmitted from within the frequency control section 13 having a timer function. Note that 15 is a power supply terminal.

If the pressure switch 16 provided in the indoor heat exchanger 8 is operated continuously at a frequency lower than the normal frequency for a certain period of time, the compressor ion will be stopped.
The protection of various devices including those removed.

Effects of the Invention Since the compressor is stopped when it is continuously operated for a certain period of time or less at a frequency below the normal use frequency, it prevents poor lubrication of the sliding parts of the compressor, protects the compressor, and improves the protection of the compressor protector. By defining the operation to be continuous for a certain period of time, it is possible to reduce the frequency of stopping the compressor and reduce the overall input.

[Brief explanation of the drawing]

1 and 2 are control characteristic diagrams of an air conditioner using frequency conversion control, FIG. 3 is a sectional view of the compressor of the air conditioner, and FIG. 4 is a diagram of the air conditioner according to an embodiment of the present invention. FIG. 2 is a block diagram of a compressor control method. 8... Indoor heat exchanger, 10... Compressor, 12... Temperature sensor, 13... Frequency control unit, 14... Frequency conversion section, 16...
...Pressure switch (compressor protector). Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 of the drawing field

Claims (1)

[Claims] The frequency converter detects the temperature of the indoor heat exchanger that constitutes the heat pump type air conditioner and controls the rotation speed of the compressor. A compressor control method for an air conditioner that completely stops the compressor after a certain period of time from when a compressor protector provided to protect the compressor is activated.