An inverter dead-time feedforward compensation scheme for PMSM sensorless drive operation

In this paper, we propose a feedforward compensation scheme of the inverter dead-time to improve the performances of a sensorless Permanent Magnet Synchronous Machine (PMSM) drive at low speed and low load torque. Based on the identification of the duty cycle error due to the inverter dead-time an analytical expression depending on the phase currents is derived. It allows adjusting the input voltage of the Extended Kalman Filter that estimates the position and the speed. The experimental results in sensorless mode show a significant improvement in the position estimation, in the balance of the phase currents and also a reduction of the torque ripples while maintaining the torque average value.