The power electronics in electric vehicles are moving towards very high efficiency and even higher power densities. A recent trend for on-board chargers is to remove the isolation transformer in order to save losses, size and cost. However, non-isolated chargers require a smart system design and control to limit leakage and touch currents to a few mA. In this paper, a novel modulation scheme eliminating the leakage current through the parasitic capacitances is proposed for three-phase neutral-point connected rectifiers/inverters. The effectiveness and performance of the proposal is validated by means of simulation and in the final paper also by experimental results based on an industrial 20-kW grid-connected NPC inverter with digital control.
