Development of permanent magnet synchronous generator drive in electrical vehicle power system

In the applications of hybrid electrical vehicle (HEV) and electrical vehicle (EV) power systems, the permanent magnet synchronous machines (PMSM) provide better torque generating capabilities, higher power density and higher power conversion efficiency. This paper develops the permanent magnet synchronous generator (PMSG) drive for the electrical vehicle. The PMSM can be driven in both motor mode and generator modes, and the main objective of this study is to establish the PMSG drive for charging the batteries embedded in EV/HEV. The voltage and torque equations of the PMSG are derived in this study. In addition, the machine parameters including back-EMF constant, winding inductance and winding resistance are estimated. Therefore, the space-vector based feedforward current control scheme is proposed via the voltage equations. The corresponding duty ratio of each power semiconductor switch in the PMSG drive is determined by the single chip microcontroller. The power switches and power diodes are chosen according to the rating of the PMSG. After the establishment of the PMSG drive, some experimental results are measured to verify the generation performance. The soft starting of the PMSG drive is developed to avoid unsuspected voltage and current transients. High power conversion efficiency of the PMSG drive and low harmonic distortion of the generator winding current are obtained via the proposed current control scheme.