Design and Performance Evaluation of a Battery Simulator

Abstract

The increasing demand on alternative fuel vehicles, especially electric vehicles (EVs), has created an enormous market, as well as great opportunities for further improvements, for battery industry. However, using battery packs as the energy source in the design/development process of new electric vehicles, is not an optimal choice, due to high cost and cycle life reduction of battery cells. Utilizing a battery simulator, with bidirectional power transactions with the grid, which can emulate different battery cell chemistries and battery pack sizes, is a viable solution to the problem.

In this work, a battery simulator is proposed which has the potential of providing a high power DC supply, while emulating multiple types of battery cell chemistries, including Li-ion, lead-acid, NiCd, NiMH, and polymer-lithium. The proposed battery simulator consists of two main parts. The first part is the battery model that generates the reference signal for the DC terminal voltage of the battery simulator according to the present value of the load current. The second part is a voltage-source converter (VSC) that controls its DC-side voltage according to the reference signal provided by the battery model. Different battery modelling approaches are introduced and compared to select the most appropriate model to be realized. The control strategy and controller tuning method are also discussed following a systematic approach. Simulations under various loading conditions are carried out and extended simulation results are presented to verify the expected capabilities of the proposed battery simulator.