Overview of the requirements and implementations of bidirectional isolated AC-DC converters for automotive battery charging applications

This paper is divided into three main parts. In the first part, i.e. Section II, a general outline of the system level aspects regarding battery chargers (power converters) for plug-in electric vehicles (PEVs) is given. Thereby, the different charging modes of the converters, the corresponding power levels, and the infrastructural facilities are discussed. Moreover, Vehicle-to-Grid (V2G) operation by means of grid-forming, grid-feeding, and grid-supporting converter functionality is briefly explained, and the input power quality and electromagnetic compatibility requirements are summarized. In the second part, i.e. Section III, the mutually coupled indices that determine the overall performance of the system, such as power losses (efficiency), volume (power density), weight (specific power), failure rate (reliability), and costs (relative cost), are outlined. In this context, the role that wide band-gap power semiconductors (e.g. SiC, GaN) can play in order to further improve the system performance is highlighted. In the third part, i.e. Section IV, a concise overview of the possible topological implementations for the mentioned power converters is provided. The focus is on conductive, isolated AC-DC converter topologies with high AC input power quality in terms of power factor correction (PFC) and harmonic distortion, and with bidirectional power flow capability in order to facilitate V2G operation.