Research On Motor Drive Control Of Frequency Conversion Refrigerator Compressor

As people demand for high efficiency and low noise of refrigerator compressors, the development of refrigerator compressors drive control technology and issue of the energy logo measures, the permanent magnet brushless motor has been widely used in the refrigerator compressor control system. Adopting the vector control and position-sensorless control technology to improve the efficiency and performance of the refrigerator compressor has become a research focus. Looking from the driving way, DC frequency conversion compressor can be driven by square wave or sine wave. Comparing with driven by square wave, sine wave drive control of refrigerator compressor has the advantages of low noise, small vibration, high efficiency, and more satisfied with the development direction of energy saving and environmental protection.This paper mainly researches on sine wave drive control technology of the DC frequency conversion refrigerator compressor. According to the characteristics of refrigerator compressor, position-sensorless control technology and vector control technology have been used in this paper. In order to improve drive control efficiency of frequency conversion refrigerator compressors, first of all, losses in the compressor was analyzed, established the minimum loss mathematical model of compressor and deduced the d-axis current when compressor is adopting the minimum loss control method. Meanwhile, synchronous motor coordinate transformation principle and implementation methods of voltage space vector PWM were introduced; using the method of sliding-mode observer to estimate the motor rotor angle and speed so as to implement compressor sensorless vector control, then analyzed the design of sliding-mode observer and how to select the sliding gain; besides, initial position and start rotor are analyzed when adopting sensorless vector control.Secondly, established the simulation model of the control system in Matlab/Simulink based on the theoretical analysis above, and verified the control strategy that has been used, the simulation results showed that the sliding-mode observer can implement compressor sensorless control, and also verified the minimum loss model and vector control.Finally, this paper designed the hardware of compressor drive control with TMS320F28035 digital signal processor and intelligent power modules as control core, completed the software design, and validated the system on 28035 experimental evaluation boards. Virtual control model simulation of the control system that has been established and evaluation experiment showed the feasibility of the control strategy and method for frequency conversion refrigerator compressor, and effect that expected has been achieved.