Method to three-phase current reconstruction of PMSM compressor

To improve the performance of permanent magnet synchronous motor (PMSM) sensorless control, the three-phase current should be sampled. According to the principle of PMSM phase current measurement, in this paper, the request of sampling time is analysed and a solution for reconstructing three phase currents by single-resistor sensor in the motor is adopted. Meanwhile, based on the analysis of non-observable regions of space vectors, a control method which synthesizes additive observed vector and compensating vector into command vector is proposed. The method has three phase current effective reconstruction in non-observable region. And based on IRMCF343 chip, a system of sensorless PMSM control has been designed. The results indicate that this method has high practical value in the field of low-cost variable-frequency air conditioner.