The battery charging power electronics interface of an electric vehicle (EV) must be capable of bidirectional power flow to enable both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) operations. In the presence of a single/three-phase AC supply, the front-end of the EV charger employs a power factor correction (PFC) rectifier, which should have the bidirectional capability to facilitate V2G mode. A conventional active rectifier functions in boost mode while performing PFC and voltage regulation. In most of the currently available EVs, however, the battery nominal voltage is low and, hence, a downstream high step-down DC-DC converter and high voltage DC bus capacitor are required in the charging interface. To overcome these issues, this work proposes a bidirectional AC-to-DC buck rectifier topology that can operate in G2V and V2G modes, both in single-and three-phase versions. The proposed topology utilizes the switched capacitors principle to achieve self-balancing of voltages in the capacitors. In addition, it is highly modular in structure. This paper describes the proposed topology, its working and modulation and its applications. The hardware proto model is used to validate the proposed power converter and the control approach to achieve PFC and voltage regulation. In addition, a comparison with other topologies is presented to demonstrate its competence.

An extensive use of electric vehicles (EVs) is evolving as an important solution to counter environmental pollution, rapid exhaustion of fossil fuels and insecurity caused by fluctuations in the price of petroleum products in the international market. The integration of EVs to the grid is required for the future enhancement of the transportation system. Grid integration of EVs also presents an interesting opportunity to solve the issues faced due to intermittent nature of renewable energy sources (RES) connected to the grid. The charging of EVs must be well coordinated with the grid otherwise it will result into an uncertain large electric load, causing peak-load and grid issues. Thus, the EV technology presents opportunities as well as challenges to the electricity grid. The development in EV technologies, battery systems, and different charging methodologies are reviewed with special focus on vehicle to grid technology as a solution to many grid issues, especially with RES connected to it. This paper presents a brief overview of these issues and various solutions.