Pre- and post-fault operation of symmetrical six-phase electric-drive-reconstructed onboard charger based on subspace current injection

The proposal of the electric-drive-reconstructed onboard charger (EDROC) provides a new idea for the research of electric vehicles (EVs), which utilizes the existing electric-drive components and shows broad commercial prospects. In this paper, pre- and post-fault operations of the EDROC incorporating a symmetrical six-phase permanent magnet synchronous motor (SSPMSM) are studied. Firstly, by employing the vector space decomposition (VSD) technique, the decoupled subspaces currents of the motor under healthy and fault conditions are solved. And their trajectories associated with torque generation are depicted, which reveals there are pulsating and rotating magnetic fields in the event of one open-phase fault (One-OPF) and two open-phase fault (Two-OPF), respectively. To eliminate the unwished magnetic fields, a subspace current injection method is proposed, which can solve the fault-tolerant current online by constructing the Lagrange function under the constraint of the minimum copper loss. Finally, the feasibility and reliability of the proposed fault-tolerant scheme is verified by experiment. This paper proposes a fault-tolerant method for the EDROC incorporating the SSPMSM. The decoupled subspace trajectories associated with torque generation are depicted, which reveals there are pulsating and rotating magnetic fields in the event of One-OPF and Two-OPF, respectively. To eliminate the unwished magnetic fields, a subspace current injection method is proposed, which can solve the fault-tolerant current online by constructing the Lagrange function considering the minimum copper loss. Finally, the feasibility and reliability of the proposed fault-tolerant scheme is verified by experiment. image