Experimental validation of off-board EV charging station with reduced active switch count

This paper presents the experimental validation of the proposed off-board electric vehicle (EV) charging station that complies with the IEEE 519-2014 power quality (PQ) standard. The proposed EV charging station constitutes a two-stage power conversion, ac-dc conversion at the front-end (interfacing the grid and dc-link), and dc-dc conversion at the end-stage (interfacing dc-link and EV battery). The ac-dc conversion stage at the front-end of the proposed EV charging station with a fewer active switch count makes it unique from other available EV charging. It utilizes multi-phase transformers to reduce the total harmonic distortion (THD) in the line current drawn, and to improve the power factor (PF). The multi-phase transformers convert the grid power supply to a multi-phase supply that makes the input line current stepped and reduces the THD, thus facilitating the reduction of active front-end power conversion, filter circuitry, and PF correctors. The multi-phase power supply is rectified to feed the dc-link from which the EV battery is charged with a dc-dc converter in constant current (CC) and constant voltage (CV) mode. The experimental validation was performed in a laboratory on a developed prototype of the proposed EV charger. The THD measured in the input line current was 3.78% with high PF (about unity) that meets the recommended IEEE 519-2014 PQ standard. The efficiency of the charger recorded was 90.4%. A comparative analysis of the proposed EV charge is presented on five metrics namely: PQ, cost, power density, control complexity, and robustness, which confirms the effectiveness of the proposed EV charger.

Automated summary

This paper validates an off-board electric vehicle charging station that meets the IEEE 519-2014 power quality standard, with experimental results showing high efficiency and the effectiveness of multi-phase transformer technology in reducing harmonic distortion and improving power factor.