JPH01134148A - Frequency control device for air conditioner - Google Patents

Abstract

PURPOSE:To reduce abnormal vibration of a compressor due to deficiency in torque, by a method wherein, in a frequency control device to control the rotation speed of the compressor of an air conditioner, the raising speed of the frequency of the compressor is increased and the lowering speed thereof is reduced. CONSTITUTION:A control device is formed with a set temperature memory means to store an indoor thermo set temperature T0, a room temperature detecting means to detect an indoor temperature T1, a comparison deciding means to decide comparison between the set temperature T0 and the room temperature T1, a frequency varying means to vary a frequency by means of an output signal, and a frequency change speed varying means to control the lowering speed of a frequency change in delay than a raising speed. Thus, by rapidly increasing the raising speed of a frequency, fall characteristic during cooling and rise characteristics during heating are improved. Since, by delaying the lowering speed of a frequency, a deficiency in torque of a compressor on a load is improved and strain of the waveform of a motor current is improved, and since the motion of a protecting device is rendered ineffective and the compressor is continuously run, amenity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a frequency control device for controlling the rotational speed of a compressor.

BACKGROUND OF THE INVENTION Conventionally, air conditioners have been equipped with this type of frequency converter to convert the frequency of power supplied to the compressor motor to control the capacity of the compressor. The rising and falling speeds change at a constant rate.

Problems to be Solved by the Invention However, the air conditioner equipped with the frequency converter as described above has the following problems.

In order to improve the startup characteristics during heating operation and the shutdown characteristics during cooling operation, setting the frequency change speed quickly will improve startup and shutdown characteristics, but when the outdoor load is large, If the temperature in the room reaches the set temperature and the frequency drops, the speed of the frequency drop is too fast and there is insufficient torque to drive the compressor, which corresponds to the load, and the compressor motor current waveform is distorted and the protection device is activated. . In addition, due to insufficient torque, the compressor vibrates significantly, causing abnormal noise and damage to connecting piping. On the other hand, if the frequency change rate is slowed down, there is no problem with insufficient torque of the compressor during overload, but there is a problem that the start-up characteristics during cooling and the start-up during heating become worse.

Means for Solving the Problems and In order to solve the above problems, the present invention provides a set temperature storage means for storing an indoor thermo set temperature TO, and a room temperature T.
1, a comparison/judgment means for comparing and determining the set temperature To and the room temperature T1, a frequency changing means for changing the frequency based on this output signal, and a frequency controlling means for controlling the rate of decrease in frequency change to be slower than the rate of increase. It is composed of change speed changing means.

Operation With the above configuration, the air conditioner frequency control device of the present invention increases the rate of increase in the frequency of the compressor and slows down the rate of decrease in the frequency of the compressor, thereby improving the start-up characteristics during heating operation and cooling operation. It has good ramp-down characteristics and can compensate for the lack of motor torque when the frequency drops, such as during overload.

Embodiment Hereinafter, an embodiment of the frequency control device for an air conditioner according to the present invention will be described with reference to the drawings.

FIG. 1 shows a circuit diagram of a frequency control device for an air conditioner according to this embodiment.

In Figure 1, 1 is a microcomputer (hereinafter referred to as LS).
11), 2 is a power transistor device, 3 is a room temperature detection circuit, 4 is a three-phase capacity control compressor, and 5 is a power supply device including a power supply, a fuse, a noise filter, a diode bridge, etc.

The operation of the frequency control device for an air conditioner configured as described above will be described below with reference to FIGS. 1 to 4.

First, Fig. 2 is a block diagram expressing the control device as a function realizing means, and the memory circuit that stores the indoor temperature setting built in LSI 1 shown in Fig. 1 is the set temperature memory circuit shown in Fig. 2. The room temperature detection circuit 3 corresponds to the room temperature detection means in FIG. 2, and the arithmetic circuit built in the LS11 that compares and determines the set temperature and the temperature detected by the room temperature detection circuit is the comparison and determination means in FIG. The built-in control circuit of LS11, which changes the frequency based on the comparison result between the set temperature and the detected temperature, corresponds to the frequency changing means in Fig. 2, and changes the frequency based on the comparison result between the set temperature and the detected temperature. L to change speed
The control circuit built into S11 corresponds to the frequency change speed changing means shown in FIG.

FIG. 3 is a flowchart showing the operation flow of the control device. First, the indoor thermostat temperature To is set, then the indoor temperature T1 is read, and it is determined whether the air conditioner is operating as cooling or heating. The temperature To and the indoor temperature T1 are compared and determined. For example, in the case of heating, when To≦T1, the frequency lowering speed is set to U2 and an output is output to lower the frequency, and the power transistor device 2 is used to control the compressor. Drive 4.

At the time of To)T1, the frequency increase rate is set to 'ftU1, an output is output to increase the frequency, and the power transistor device 2 drives the compressor 4.

Figure 4 shows the characteristics of the frequency change rate of the control device, and shows the rate of increase from frequency 0 to quantity 1, 1-0/
According to the present embodiment, by increasing the rate of increase in frequency as compared to the rate of decrease from the mouth to O at 111,
The falling characteristics during cooling and the rising characteristics during heating are improved. In addition, by slowing down the rate of frequency decline, the lack of torque in the compressor relative to the load is corrected, and the waveform distortion of the motor current is improved, eliminating the need for the protection device to operate and improving comfort as the compressor operates continuously. Improved. In addition, large vibrations of the compressor due to insufficient torque can be alleviated, and abnormal noises can be suppressed.

Effects of the Invention As described above, according to the present invention, by changing the rate of rise and fall of the frequency, the falling characteristics during cooling and rising during heating are improved, and the compression caused by insufficient torque when the frequency falls is improved. The waveform distortion of the motor current is improved, the protection device does not operate, and comfort is improved, and the abnormal vibration of the compressor due to insufficient torque is reduced, reducing noise and piping vibration.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit diagram of a frequency control device for an air conditioner according to an embodiment of the present invention, FIG. 2 is a block diagram expressing the control device using function realizing means, and FIG. 3 is a flowchart of the control device. FIG. 4 is a characteristic diagram of the frequency change rate of the same control device, and FIG. 5 is a characteristic diagram of the conventional frequency change rate. 1...Microcomputer, 3...
Room temperature detection circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4 Figure t2

Claims (1)

[Claims] a set temperature storage means for storing the indoor thermoset temperature T_0; a detection means for detecting the room temperature T_1;
a comparison determination means for comparing and determining _0 and the room temperature T_1;
A frequency control device for an air conditioner, comprising a frequency changing means for changing the frequency according to the output signal determined by the comparison and determining means, and a frequency changing speed changing means for controlling the decreasing speed of the frequency change to be slower than the increasing speed. .