A Harmonic Current Injection Technique for Dual‐Channel Integrated Onboard Charger

ABSTRACT The concept of the dual channels provides integrated onboard charger (IOC) with robust fault tolerance capability and high reliability. This paper investigates a dual‐channel IOC system integrated symmetrical six‐phase permanent magnet synchronous machine (SSPMSM) drives. A key challenge in this system is the inevitable occurrence of unbalanced charging powers between the two channels, which results in a rotating field and hence a charging torque generation during charging. To address this issue, a harmonic current injection technique is proposed, leveraging the inherent multicontrol degrees of freedom of the SSPMSM to counteract the rotating field. By injecting harmonic components of the x ‐, y ‐, and 0 1 ‐axes, the desired straight‐line‐shaped trajectory can be maintained in the α – β subspace. Then, the specified harmonic components can be calculated with two constraints of balanced grid currents and zero average charging torque. Subsequently, a unified controller is designed for dual‐channel IOC. Finally, the efficacy of the harmonic current injection technique is validated through experimentation.