High impedance grounding for onboard plug-in hybrid electric vehicle chargers

Plug-in Hybrid Electric Vehicles (PHEV) are currently on the early stages of production. PHEV interacts with the electric grid to exchange power through a power conditioner unit (PCU). Developing a PHEV PCU is a subject of growing interest in industry and academia. The related standards are currently under development and the required guidelines to design and develop PHEV PCU are not well established. This paper investigates the available standards regarding grounding requirements and the role of galvanic isolation among the concepts affecting the design procedure of onboard PHEV PCUs. Both isolated and non-isolated PCUs are studied in relation to operating conditions, and safety concerns. The high impedance reference grounding method is suggested as a possibility of grounding connection and compared to the direct grounding connection for both isolated and non-isolated PHEV PCUs.