A bidirectional series resonant matrix converter topology for electric vehicle DC fast charging

A series resonant matrix converter (MC) based topology for high power electric vehicle (EV) battery charging is presented. The system performs DC fast charging and is capable of bidirectional power flow, for V2G (vehicle-to-grid) applications. The proposed topology can be divided into three sections: (i) a front-end 3×1 matrix converter, (ii) L_rC_r series resonant tank and high frequency (HF) transformer, and (iii) a single phase PWM rectifier. The matrix converter takes a three phase line frequency voltage and produces a high frequency (14.94 kHz) AC output. The resonant tank frequency is set to 13.7 kHz and helps to achieve zero voltage switching (ZVS) turn ON and low turn OFF switching losses. The secondary of the transformer is then interfaced to the EV battery bank through a PWM rectifier. The advantages of such a system include high efficiency due to soft switching operation, low VA transformer ratings due to resonant operation, and high power density due to the absence of electrolytic capacitors. A design example rated 30 kW, which charges a 500 V battery system, is presented. Analysis and simulation results demonstrate the performance of the proposed bidirectional topology. Preliminary experimental results are provided for a scaled down prototype operating at 500 W using a 15 kHz ferrite transformer.