Novel reactive power control strategy based on constant DC-capacitor voltage control for reducing the capacity of smart charger for electric vehicles on single-phase three-wire distribution feeders

This paper proposes a novel reactive power control strategy to reduce the capacity of the previously proposed smart charger for electric vehicles (EVs) on single-phase three-wire distribution feeders. The proposed reactive power control strategy is based on the constant dc-capacitor voltage control of the grid-connected PWM rectifier. Any calculation blocks of load-side active current are not needed. Thus, we offer the simplest reactive power control strategy. The basic principle of the proposed reactive power control strategy is discussed in detail, and then confirmed by a digital computer simulation using PSIM software. A prototype experimental model is constructed and tested. Experimental result demonstrates that balanced source currents with a power factor of 0.9, which is acceptable value in Japanese home appliances, are obtained on the secondary side of the pole-mounted distribution transformer during battery charging operation in EVs reducing the capacity of the smart charger by 36% as compared with that of the smart charger with the previously proposed control strategy.