JPS60228782A - Controller of air conditioner - Google Patents

Abstract

PURPOSE:To prevent the bubbling phenomenon, shortage of lubricant and liquid from being compressed inside a compressor by keeping the compressor to run at a low speed for a certain period from the starting time of the compressor. CONSTITUTION:A compressor is started in response to a starting command. After the starting, the compressor is urged to raise the revolutional speed as fast as possible to a low speed value at which sufficient lubricant can be supplied. The low revolutional speed is kept for a certain period with the aid of a timer. The compressor is then placed in a stable condition. An example of the low speed revolutional speed to be increased is 3,000rpm.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control device for a capacity control air conditioner.

[Background of the invention]

A control method for a conventional capacity-controlled air conditioner, particularly one in which the rotational speed of a compressor motor is made variable, will be described with reference to FIG.

In FIG. 1, after the air conditioner is started, a rotation speed commensurate with the load is commanded to the compressor, and the compressor rapidly increases its rotation speed to reach the commanded number of times N1-L. At this time, the smaller the commanded rotational speed Nl (time t at which it reaches)l is, the faster the air conditioner starts up, and its functions can be activated sooner.

However, since such an air conditioner reaches its maximum rotational speed in a short period of time, it has the disadvantage that the stability of the refrigeration cycle of the compressor and the air conditioner is neglected. Specifically, the rapid increase in the compressor rotational speed induces a bubbling phenomenon inside the compressor, and the lubricating oil in the compressor dissolves into the refrigerant and is discharged into the refrigeration cycle, resulting in a lack of lubricating oil. In the worst case, the compressor will become locked. Furthermore, depending on the load condition, the liquid refrigerant may be compressed for a short period of time before the refrigeration cycle reaches a stable state due to a rapid increase in the rotational speed, which also poses a risk of locking the compressor.

It is.

[Summary of the invention]

In other words, after starting the air conditioner, even if the command rotation speed corresponding to the load is a high rotation speed, the rotation speed of the compressor is maintained at a low speed, and after the refrigeration cycle and compressor have settled into a stable equilibrium state. , the rotational speed is increased to the commanded rotational speed and normal operation is maintained.

[Embodiments of the invention]

The present invention will be explained below with reference to an embodiment shown in FIG. Second
In the figure, after the air conditioner is started, the rotation speed stops increasing when it reaches a low rotation speed. The term "low speed" as used herein refers to the lowest rotational speed of the compressor, that is, the rotational speed at which the compressor can be sufficiently lubricated and a stable state can be maintained without any problems. The locking state of the compressor described above can be avoided by maintaining the stability of the refrigeration cycle while maintaining the low rotational speed and, after a certain period of time, excluding the commanded rotational speed according to the load.

Note that it is desirable to increase the rotation speed of the compressor to a low speed as quickly as possible. This is because the compressor is not sufficiently lubricated from startup to low rotational speed. usually,
For conventional compressors, the minimum rotational speed without any problem with lubrication is 15.
It is around 00 rpm.

Further, although not shown in the drawings, the low rotational speed can be set to around 3000 rpm, which is the rated rotational speed of a conventional compressor. This is 3000 when a conventional compressor is applied to the air conditioner of the present invention.
This is because it is designed to be in the most stable state around rpm.

FIG. 6 shows a block diagram of the control device of the present invention.

To explain the present invention from a control perspective, in FIG. 3, the indoor side control section 1 detects the temperature on the indoor side, takes the difference ΔT from the temperature set by the user, and regards this as a load.

After converting this load, that is, the temperature difference ΔT, into a command rotation speed NR, when manual power is applied to the compressor drive unit 2 on the outdoor side, the compressor 6 starts based on the command and accelerates to the low speed rotation speed of the compressor. . After the low speed rotation speed is detected by the compressor drive section 2, a timer is activated for a certain period of time, and the compressor rotation speed is increased to the commanded rotation speed when the time is up. 4 is an indoor air conditioner, and 5 is an outdoor air conditioner.

〔Effect of the invention〕

As described above, the present invention does not increase the compressor rotation speed to the command rotation speed in a short time, but maintains operation at a low rotation speed once during the increase, and after the refrigeration cycle and compressor reach a stable state. , it is possible to provide a control method that reaches a predetermined commanded rotation speed, and therefore a locking state of the compressor can be avoided.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a control method of a conventional rotation speed controlled air conditioner. FIG. 2 is a diagram showing a control method of the rotation speed controlled air conditioner of the present invention. FIG. 3 is a control block diagram of the present invention. 1... Indoor side control section, 2... Compressor drive section, 6...
-Compressor, 4...Indoor air conditioner, 5...Outdoor air conditioner. 1F2 diagram

Claims (1)

[Claims] In an air conditioner having a compressor with a built-in variable rotation speed electric motor, the rotation speed of the compressor electric motor is maintained at a low rotation speed after the air conditioner is started, and the rotation speed is increased after a certain period of time has elapsed. Features: Air conditioner control device.