Sensorless vector control of IPMSM drive system with small DC-link capacitor

This paper studies a sensorless drive system of interior permanent magnet synchronous motor (IPMSM) fed by single phase diode rectifier with small dc-link capacitor. Because the large electrolytic capacitors have the disadvantages of both large volume and limited life span, the system uses small dc-link capacitor instead of traditional large electrolytic capacitor. In the system, the inverter controls not only the speed of the motor, but also the input grid current waveform. A novel flux weakening scheme generating d-axis current reference is devised and q-axis current is modified for the unity power factor. A speed and position estimation method based on adaptive full order observer is developed to apply to the drive system. The simulation results illustrate the validity and efficiency of the proposed method.