JPH0510570A - Air conditioner control method - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the heating operation capacity of the air conditioner. [Structure] The figure is a block diagram of a main part of a control system of an air conditioner, in which 1 is an indoor temperature Tr detection unit, 2 is an indoor heat exchanger temperature Tn detection unit, 3 is an indoor control unit, and 4 is a room. The outer control unit 5 is an inverter unit controlled by the outdoor control unit 4, 6
Is an inverter-controlled compressor. When the indoor temperature Tr reaches the lower limit value of the preset temperature control zone during the heating operation, the temperature of the indoor heat exchanger (the discharge pipe temperature of the compressor 6) Tn is detected by the temperature detecting means 2. This temperature T
When n is greater than 55 ° C., the operating frequency of the compressor 6 is increased by 1 Hertz every 2 seconds, for example, and the temperature Tn is 55.
When the temperature is lower than 0 ° C, the operating frequency of the compressor 6 is increased by 1 Hertz every 0.4 seconds, for example. When the room temperature reaches the upper limit value, the operating frequency of the compressor 6 is decreased by 1 Hz every 1 second.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a compressor during heating operation of an air conditioner.

[0002]

2. Description of the Related Art In an air conditioner, when the room temperature during heating operation reaches a lower limit value of a preset temperature control zone, the operating frequency of the compressor is, for example, 1 hertz / 0.4.
It is controlled so as to increase at a speed of 2 seconds and to decrease the operating frequency of the compressor at a speed of, for example, 1 hertz / second when the indoor temperature reaches the upper limit value. On the other hand, the discharge pressure of the compressor is determined to have a maximum allowable value of, for example, 26.5 kilograms / square centimeter G (G represents a gauge pressure). Although it is necessary to control the operating frequency of the compressor, there are technical and cost problems in directly detecting the discharge pressure of the compressor. It is estimated from the temperature. However, in this method, when the discharge pressure sharply rises from the point a to the point b as shown in FIG. 3A, the discharge pipe temperature detected by the temperature detecting means is the actual discharge pressure. Since the change (rising speed) cannot be followed and a time delay occurs between the two, the discharge will occur if the upper limit value of the temperature control zone shown in FIG. 3B is set higher than the position shown in the drawing. The pressure will exceed its maximum allowable value of 26.5 kilograms per square centimeter G. Therefore, when setting the upper limit value (operating temperature) b ′ of the temperature control zone, it should be set to a lower value in advance in consideration of the above-mentioned time delay, and the discharge pressure can reach its maximum allowable value even in the case of overload operation. I try not to exceed the value.

[0003]

However, in actual operation, the rise of the discharge pressure may be gradual as shown between a and c in FIG. 3A, and thus the pressure change is gradual. In this case, since there is almost no time delay between the discharge pipe temperature detected by the temperature detecting means and the actual discharge pressure, the discharge pipe temperature before the discharge pressure (point c) reaches its maximum allowable value. Will reach the upper limit (operating temperature) c ′ of the temperature control zone. In such a case, the discharge pressure (point c) has a sufficient margin with respect to the maximum allowable value of 26.5 kilograms / square centimeter G, and there is a problem that the original performance of the air conditioner cannot be fully exerted. .. Therefore, it is an object of the present invention to provide a method for controlling an air conditioner that solves such a problem and is capable of sufficiently exhibiting the ability of the air conditioner.

[0004]

The present invention has been made to solve the above problems, and when the indoor temperature reaches the lower limit value of the preset temperature control zone, the operating frequency of the compressor is reduced. In an air conditioner that is controlled so as to increase at a predetermined speed and decrease the operating frequency of the compressor at a predetermined speed when the room temperature reaches an upper limit value, the indoor side detected by the temperature detecting means during heating operation. When the heat exchanger temperature is equal to or higher than a predetermined value, the operating frequency of the compressor is increased at a slower rate, and when the indoor heat exchanger temperature is a predetermined value or less, the operating frequency of the compressor is increased at a faster rate. I decided to control it.

[0005]

With the above control method, when the indoor temperature reaches the lower limit value of the temperature control zone during the heating operation, the operating frequency of the compressor rises, but at that time, the temperature of the indoor heat exchanger exceeds a predetermined value. In other words, if the discharge pressure of the compressor is able to reach the maximum allowable value rapidly, the increase rate of the operating frequency of the compressor is slowed down. The detection delay of the temperature of the inner heat exchanger is reduced, and the upper limit value of the temperature control zone can be increased by the amount of the reduction of the detection delay. If the temperature of the indoor heat exchanger is equal to or lower than the predetermined value, the operating frequency of the compressor is increased at a higher speed.However, if the temperature of the indoor heat exchanger is increased again from the predetermined value or lower, Since the temperature of the indoor heat exchanger rises almost following the discharge pressure of the compressor, the difference between the discharge pressure and its maximum allowable value is reduced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram of a main part of a control system of an air conditioner. In the figure, 1 is a temperature detecting means for detecting the indoor temperature, 2 is a temperature detecting means for detecting the temperature of the indoor heat exchanger, and 3 is an indoor blower based on an input signal from the temperature detecting means 1, 2, etc. (Not shown) and the like, and an indoor-side control unit that exchanges signals with the outdoor unit side,
Reference numeral 4 denotes an outdoor control unit provided inside the outdoor unit, 5 denotes an inverter unit whose drive is controlled by the outdoor control unit 4, and 6 denotes an inverter-controlled compressor.

By the way, the indoor control unit 3 has a memory for storing an indoor temperature set by a remote controller or the like,
The indoor side control unit 3 obtains a temperature difference between the set temperature stored in the memory and the indoor temperature Tr obtained from the temperature detecting means 1, and transfers a frequency command code according to the temperature difference to the outdoor side control unit 4. At the same time, it is determined whether or not the temperature Tn of the indoor heat exchanger detected by the temperature detecting means 2 is 55 ° C. or higher. When Tn ≧ 55 ° C., the signal “L” is output.
When Tn <55 ° C., the signal “H” is output to the outdoor side control unit 4
It is designed to output to. On the other hand, in the outdoor side control unit 4, a control signal (compressor 6) for controlling the drive of the inverter unit 5 based on the frequency command code from the indoor side control unit 3.
The operating frequency of the compressor 6 is controlled to drive the inverter unit 5, and when the above signal "L" is input, the operating frequency of the compressor 6 is increased by 1 Hz every 2 seconds, and the above signal " When "H" is input, control is performed to increase the operating frequency of the compressor 6 by 1 Hz every 0.4 seconds.

FIG. 2 is a flow chart showing the state of control. The heating operation is started in step ST1, and when the process proceeds to step ST2, the room temperature Tr is detected by the temperature detecting means 1 shown in FIG. In step ST3, the room temperature Tr is compared with the set temperature Ts to calculate the temperature difference. In step ST4, the operating frequency of the compressor 6 is determined according to the temperature difference calculated in step ST3. Continuing,
In step ST5, the temperature detecting means 2 shown in FIG. 1 detects the temperature Tn of the indoor heat exchanger, and in step ST6, whether the temperature Tn of the indoor heat exchanger detected in step ST5 is 55 ° C. or higher, for example. Is determined, and if the determination result is Tn ≧ 55 ° C., the process proceeds to step ST7.

Then, in this step ST7, the compressor 6
The operating frequency is increased by 1 Hz every 2 seconds. if,
If the determination result in step ST6 is Tn <55 ° C., the process proceeds to step ST8. Then, this step ST
In 8, the operating frequency of the compressor 6 is increased by 1 Hz every 0.4 seconds. In the next step ST9, it is determined whether the temperature Tn of the indoor heat exchanger has reached the upper limit value of the temperature control zone, and if it has not reached the upper limit value, the process is returned to step ST2 and a series of operations are repeated. .. And
When the temperature Tn of the indoor heat exchanger reaches the upper limit value of the temperature control zone, the process proceeds to step ST10, and the operating frequency of the compressor 6 is decreased by 1 Hz every 1 second. It should be noted that steps ST2 to ST5 are mainly performed by the indoor side control section 3, and steps ST6 and subsequent steps are mainly performed by the outdoor side control section 4.

[0010]

According to the air conditioner control method described above, the overload protection operating temperature, that is, the upper limit value of the temperature control zone can be increased, so that the capacity of the air conditioner is sufficient. And the comfort during heating operation is further improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a control system of an air conditioner showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a control method of the present invention.

FIG. 3 is a diagram illustrating a conventional control example.

[Explanation of symbols]

 1 Temperature Detection Means 2 Temperature Detection Means 3 Indoor Side Control Section 4 Outdoor Side Control Section 5 Inverter Section 6 Compressor

Claims (1)

Claim: What is claimed is: 1. When the room temperature reaches the lower limit value of the preset temperature control zone, the operating frequency of the compressor is increased at a predetermined speed, and when the room temperature reaches the upper limit value, the compressor is compressed. In an air conditioner controlled to lower the operating frequency of the machine at a predetermined speed, if the indoor heat exchanger temperature detected by the temperature detecting means during heating operation is equal to or higher than a predetermined value, the compressor A method for controlling an air conditioner, characterized in that the increasing rate of the operating frequency of the compressor is increased when the increasing rate of the operating frequency is slowed and the indoor heat exchanger temperature is equal to or lower than a predetermined value. ..