A Charging-Torque Suppression in Three-Phase Integrated Dual-Battery Charger for EV Based on Six-Winding Machine Drive System

This article proposes a torque elimination in three-phase integrated dual-battery charger using a six-winding permanent magnet synchronous machine (PMSM) drive system. The proposed system can charge both a high voltage main-battery and low voltage secondary-battery from the reconfiguration of the motor drive and the existed half-bridge converter as dual battery charger. Due to the anisotropic characteristic of the motor windings’ inductance used as a grid harmonic current filter, an unbalanced current sharing can occur in stator windings during charging, which leads to torque production. In this article, a balanced current-sharing technique is proposed to cancel the charging torque and improve the performance of charging. The theoretical analysis of the charging current distribution within stator windings is conducted to determine the electromagnetic torques in both unbalanced and balanced current-sharing scenarios. The control algorithm, which is based on equal current sharing under different rotor positions, and winding-short-circuit-fault, is implemented. Simulation and experimental results are provided to validate the theoretical analysis.