A Winding-based DC-Bus Capacitor Discharge Strategy for PMSM Drive System in EVs Considering Position Sensor Fault

Abstract

This paper directly uses the machine windings to discharge the capacitor voltage in the PMSM drive systems when an emergency happens to electric vehicles. The winding-based method needs to control the d, q-axis current in the motor and it requires accurate position information during the whole discharge process. Whereas, the position sensor installed in the motor is likely to fail due to the violent vibration and impact in the emergency. Considering the position sensor faults, this paper proposes a more reliable current control algorithm based on a sliding mode position estimator to bleed the capacitor voltage. The proposed discharge strategy treats the machine as a generator so as to regulate the DC-bus voltage, and takes advantage of the maximum discharge capacity of the drive system and manages to maintain the discharge time within 2.7 s for the studied system. Simulation and experimental results are presented to verify the effectiveness of the proposed algorithm.