PMSM position sensorless control in the inverter overmodulation range

In this paper, Permanent Magnet Synchronous Motor(PMSM) position sensorless control system in the inverter overmodulation range has been proposed. Operating PMSM in the inverter overmodulation range achieves fast torque response and widens high-speed drive region of PMSM. In the range, however, because of the effect from harmonic currents, a closed loop current control system become unstable, further more because of harmonic voltage output from the inverter makes position estimation error and it may destabilize sensorless control system. First of all describes mechanism of destabilization of sensor-less control system in the overmodulation range. Second of all propose PMSM sensorless control system with the inverter model and the harmonic current model which stabilizes control system. Last of all the experimental results show that the proposed sensorless control system achieves widening high-speed drive region.