Harmonic distortion caused by EV battery chargers in the distribution systems network and its remedy

An effective way to minimise harmonic pollution in power systems is by careful design of the equipment connected to them. It is important for designers of equipment associated with emerging technologies to be aware of the potential impact of their designs on power system quality. One such upcoming technology is electric vehicle (EV) battery charging which may contribute to high harmonic distortion in the power system during the charging period. The literature notes total harmonic distortion of up to 50%. These findings are the impetus behind the present paper, where an EV battery charger has been designed, with an inherent power quality control feature. A parallel power circuit topology has been proposed on an existing ferroresonant charger, which ensures that the THD of the input current remains within the acceptable harmonic distortion limits of the distribution system. The design and control of the battery charger are elaborated upon in the paper and simulation results are presented which confirm the performance of the charger.