Dead-Time Effect Analysis and Compensation for a Sliding-Mode Position Observer-Based Sensorless IPMSM Control System

This paper presents an extended electromotive-force-based discrete-time sliding-mode observer (DSMO) for rotor position/speed sensorless control of interior permanent-magnet synchronous machines (IPMSMs). Without using voltage sensors to measure IPMSM terminal voltages, the reference voltages generated by the vector control system are used as inputs for the DSMO. However, due to the inverter dead-time effect, the mismatch between the reference voltages and actual terminal voltages will degrade the performance of DSMO. In this paper, the periodically oscillating rotor position estimation error caused by the dead-time is first analyzed. Then, a dead-time compensation scheme is proposed to mitigate this position estimation error. The proposed DSMO with the dead-time compensation scheme is validated on an IPMSM control system used in heavy-duty, off-road, hybrid, and electric vehicles.