Improved Operation and Control of Single-Phase Integrated On-Board Charger System

Single-phase grid-connected integrated on-board charger (IOBC) can significantly reduce the cost and the bulk of electric vehicles and has been used in real products. However, there are still two problems that have not been discussed and solved. First, when permanent magnet synchronous motor drives are used for single-phase IOBC, there are second-order current harmonic and the possibility of instability in the system. Second, when multiphase motor (MPM) drives are used for single-phase IOBC, the currents' assignment strategy and the dc voltage utilization of inverter need to be dissected. This article does detailed research works about these two problems. The origin of the second-order harmonic and the instability are exposed. Furthermore, proportional-double-resonant regulator and adaptive proportional (P) parameter control schemes are proposed to solve these problems. The operation principle of single-phase IOBC with MPM drive is analyzed. Two different operating modes are recommended, and an optimal zero-sequence voltage is designed to increase the dc voltage utilization capability of the inverter. At last, the feasibility of the proposed operation and control schemes are verified by experiments.