General Derivation Law With Torque-Free Achieving of Integral On-Board Charger on Compact Powertrains

Abstract

Integrated charging for electric vehicles (EVs) is considered as a good transitional scheme to expand the mileage range under the battery capacity limit. It can save the costs and reduce the volume by replacing the on-board charger, and can increase the charging power by reusing the high power propulsion system. Then, the charging and propulsion system will therefore be light and compact. As the charging topology is based on the propulsion system, the design degrees of freedom are not very high, further resulting in limited application. And the laws of topological construction are lacking. Therefore, most of the integrated charging schemes are designed for a specific occasion and are difficult to adopt for other applications. In this article, a general derivation law with a unified design criterion is proposed to improve the generality of integrated charging, by considering the charging torque and equivalent filter inductance of the multiplexed converter and motor. The criterion is illustrated and analyzed in a specific scheme that is applied in the Toyota plug-in hybrid EV. The simulation results in a software-in-the-loop environment and experimental results in a down-scaled prototype are demonstrated to confirm the validity of the unified criterion and the effectiveness of the control schemes. It is suitable for the design of integrated charging solutions with multiphase power and multiphase motors.