Advanced Hybrid Battery System for Power Driving and Regeneration of Electric Vehicles

This paper presents a new Hybrid Battery System (HBS) for power driving and regeneration of Electrical Vehicle (EV) applications. The proposed topology employs two Lithium-Ion Batteries (LIB) (i.e.; main battery and sub-battery) with different specifications. The main LIB has high capacity with low power capability, whereas the sub-battery has low capacity with high power capability. Each battery is controlled by a bidirectional dc-dc converter connected in series with a common inductor during driving and regeneration modes of the EV. Therefore, both dc-dc converters and the sub-battery are installed between the main battery storage element and three-phase motor drive dc-ac voltage source inverter (VSI) to reduce main battery current and loss, hence keep its temperature within the permissible limits, which in-turn enhances its lifetime and prevent EV sudden power down at high temperature of LIBs. Also, the proposed HBS provides dc voltage control at the input dc terminals of the motor drive VSI according to the reference speed, which in-turn reduces inverter switching loss and enhances the inverter efficiency. The validity of the proposed HBS has been verified theoretically using PSIM simulation software and experimentally through laboratory prototype of 200V, 2kW.