Comparative Analysis of Integrated Onboard Battery Chargers for Zero Charging Torque Using PMSM with and without Neutral Point Access

This study compares the performance of integrated onboard battery chargers (IOBCs) in electric vehicles (EVs) when using motor windings as filter inductors. Both conventional three-wire three-phase permanent magnet synchronous motor (PMSM) and neutral-point-accessible PMSM (NP-PMSM) are studied in a split single-phase charger. A charging torque minimization strategy is analysed to address the torque oscillations that are inherently generated in conventional PMSMs. Simulation studies are conducted to analyze the charging torque oscillations in IOBCs based on conventional PMSMs and NP-PMSMs. The associated power losses in the power converter are meticulously examined to gain valuable insights for selecting an appropriate IOBC configuration. The study demonstrates that NP-PMSM-based IOBCs offer significant advantages, exhibiting no charging torque and lower power loss compared to conventional PMSM-based IOBCs.