Variable-frequency Speed Control System Of Air Conditioning Compressor Based On The Four-switch Three-phase Rectifier

As the popularity of frequency conversion air conditioning, demands for variable frequency air conditioner control performance become higher and higher.So, this paper begins from two aspects to study variable-frequency speed control system of air conditioning compressor based on the four-switch three-phase rectifier,one is improving the system power factor, the other is lower the speed pulse under low speed operation of air conditioner compressor. In the study, system mathematical model is built and effective control strategy is made, simulation verification is also made.The mathematical model of Three Phase Four Switch Rectifier(TPFSR)topology and Permanent-Magnet Synchronous Motor(PMSM) is deduced and analyst, and the basic control strategy is determined. For the problems of TPFSR capacitor voltage unbalance and speed fluctuation under low speed operation of air conditioner compressor, this paper make the simulation and analysis, as the theoretical and simulation basis of the further research.According to the generating mechanism of TPFSR bus capacitor voltage unbalance, this paper choose a current feedforward control method, the effectiveness of the chosen control strategy is validated by the simulation.System’s operation frequency is same as the fluctuation frequency of the pulse of PMSM load torque, for this property, this paper introduces a kind of Proportional Resonant(PR) in the traditional PI controller. This control method can refrain the speed fluctuation which pulse frequency is same as the load torque fluctuate frequency. This paper also validate this control method by MATLAB simulation.At last this paper designs the important parameters of TPFSRT and the main control circuit. The entire control strategy of variable-frequency speed control system of air conditioning compressor based on the four-switch three-phase rectifier is presented. And the simulation is made, the result shows that the designed system can operate as expect.