Study on phase current reconstruction of inverter compressor based on single-resistor sampling

LI Yue， XV Ming， HUANG Yue-jin， GU Jiang-ping， SHEN Xi
（College of Mechanical Engineering， Zhejiang University of Technology， Hangzhou 310014， China）

Abstract： In order to improve the control efficiency of the DC inverter compressor and reduce cost，the phase current of motor stator should be sampled. Aiming at the relationship between the motor three-phase current，DC bus current and inverter switch states，three-phase current reconstruction using only a single-resistor in the inverter DC link was proposed. Firstly，based on the mathematical model of permanent magnet synchronous motor（PMSM），the key technology and difficulties in reconstructing three-phase current by single-resistor sensor were analyzed. Then，a mathematical method of using predictive state observer to the non-observable regions of the middle and high frequency modulation region in the process of space vector PWM modulated was adopted. The three-phase current was constructed effectively and accurately. Finally，based on STM32 chip，a system of senseless DC inverter compressor control was designed. The hardware circuit of the single-resistor sensor was given. The results indicate that this method can correctly reconstruct the phase current and has a high practical value in the field of low-cost frequency conversion refrigerator.
Key words： inverter compressor； vector control； single-resistor current sampling； phase current reconstruction； permanent magnet synchronous motor（PMSM）