Reduced-Capacity Smart Charger for Electric Vehicles on Single-Phase Three-Wire Distribution Feeders With Reactive Power Control

In this paper, we propose a new control algorithm to reduce the capacity of a previously proposed smart charger for electric vehicles (EVs) on single-phase three-wire distribution feeders with reactive power control. The basic principle of the proposed control algorithm is discussed in detail. It is shown that controlling the reactive power on the source side reduces the capacity of the previously proposed smart charger. A digital computer simulation is implemented to confirm the validity of the proposed control algorithm using PSIM software. A prototype experimental model is also constructed and tested. Experimental results demonstrate that balanced source currents with a power factor of 0.9, which is acceptable for Japanese home appliances, are obtained on the secondary side of the pole-mounted distribution transformer during both the battery charging and discharging operations in EVs. The capacity of dc capacitor $C_{\rm DC}$ is also reduced by 37% with the proposed reactive power control algorithm.

I. Introduction

ELECTRIC vehicles (EVs) are now commercially available. The Mitsubishi i-MiEV is a five-door hatchback electric Kei car, and the Nissan LEAF is a medium-size five-door hatchback electric car. The lithium-ion batteries equipped in the i-MiEV can store an electric energy of 16 kWh, whereas in the LEAF, the maximum stored electric energy is 24 kWh. These EVs are highly mobile with the stored electric power. As a result of this mobility, the interesting concept to inject the stored power of EVs into grids and homes (vehicle-to-grid and vehicle-to-home, respectively) has been proposed [1]– [4]. To achieve this, a pulsewidth-modulated (PWM) rectifier with a bidirectional dc–dc converter is used as a charger. The PWM rectifier with the bidirectional dc–dc converter is used with a photovoltaic (PV) system [5]. Control and power management of the PV system has been discussed.