One-driving-multiple frequency-change central air conditioner

Abstract

The invention belongs to the technical field of central air conditioners, and in particular relates to a central air conditioner with multiple inverters. Including compressor unit, four-way valve, condenser, at least one indoor evaporator, and refrigerant, connecting pipes, an electronic expansion valve is installed in front of each indoor evaporator; on the main pipe between the condenser and all indoor evaporators , A throttling device in which a thermal expansion valve and a check valve are connected in parallel is installed. The one-drag multi-frequency conversion central air conditioner of the present invention has the advantages of simple installation, low development cost and long service life.

Description

[0001] (1) The technical fields mentioned [0002] The invention belongs to the technical field of central air conditioners, and in particular relates to a central air conditioner with multiple inverters. (2) Background technology [0003] One-to-multi-inverter air conditioner is composed of one inverter compressor and multiple terminal evaporators connected to the refrigerant air-conditioning system. Since the operation mode and wind speed of each terminal evaporator can be set freely by the user, the capacity of the air-conditioning system will change. Very wide, its control is quite difficult. In order to adapt to the load change of the terminal evaporator, an electronic expansion valve is used to control the flow of refrigerant and the state quantity of the refrigeration cycle. In the variable-capacity air-conditioning system driven by frequency conversion, in order to improve the cooling flow control characteristics and increase the flow control range, the current air-co...

AI Technical Summary

Problems solved by technology

The electronic expansion valve adopts PID control, but due to the regulator parameter K P 、K I 、D D Improper selection will cause the refrigeration system to oscillate, because the PID adjustment cannot achieve a good control effect on the nonlinear system, and the control is very complicated. For this reason, foreign companies have improved the PID control algorithm and applied for a patent to perform more complicated Calculation to realize the control of the electronic expansion valve

my country's central air-conditioning manufacturers have not yet mastered this technology, and cannot fully realize the control of the electronic expansion valve. Generally, they purchase the patented technology of foreign manufacturers.

[0004] However, the electronic expansion valve has the following disadvantages. ①The development of the electronic expansion valve control system requires a long cycle and a large investment, requiring a set of complex algorithms, and its calculation value needs to be verified by all parties. Since the operating conditions of the air conditioner vary widely, it is impossible Verify various operating conditions, rendering it unreliable in use

②Traditional central air-conditioning, its indoor and outdoor coupling control, is very sensitive to system changes. Due to changes in the length, height, and switch adjustment of the end evaporator of the pipeline, it is easy to cause the control of the entire system to be unstable.

③Because the system is unstable, it is easy to cause liquid return, overheating, and compressor damage

④ When heating, the opening of the expansion valve of the outdoor unit should be adjusted according to the opening of the electronic expansion valve of each terminal evaporator, which makes the logic operation more complicated, and the fluctuation of the valve opening is relatively ordinary, which affects the electronic expansion. valve service life

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