Mutual Inductance Compensation for Charging Torque-Free Multiphase Integrated On-Board Chargers

This paper investigates mutual inductance effects in integrated on-board charging (IOBC) systems that repurpose multiphase permanent magnet synchronous motor (PMSM) windings as filter inductors. The parameter imbalance caused by motor winding mutual inductance will lead to current distortion and DC-link voltage ripple. The parameter imbalance caused by motor winding mutual inductance will lead to current distortion and DC-link voltage ripple. These effects further result in electromagnetic torque oscillations, harmonic amplification, and safety concerns. Thus, a resistance-inductance compensation method based on equivalent circuit modeling is proposed. The winding inductance characteristics is first analyzed to demonstrate how imbalanced parameters create current imbalance and DC-link voltage ripple. After deriving the equivalent circuit model, the proposed resistance-inductance compensation method is applied to the grid-side three-phase circuit and further regulated by Model predictive control (MPC) control to mitigate these effects. Finally, simulation results show that three-phase current imbalance reduces from 5.24% to 0.66%, grid current THD drops from 2.83% to 0.38%, and 100 Hz DC-link ripple THD decreases from 6.62% to 2.93%. The compensation method features simple control logic and broad PMSM applicability, enhancing charging safety and power quality.