Isolated Single – Stage Interleave Resonant Converter for EV Charger with Passive Output Ripple Cancellation Circuit

Despite the attractiveness of isolated single-stage power factor correction (PFC) converter in terms of efficiency and lower component count, they are mostly plunged with the drawback of high DC bus voltage at the input side and twice the grid frequency ripple appearing at the output. This behaviour drives the converter cost higher due to higher voltage switches and large output capacitance needed in suppressing the low-frequency ripple. However, an isolated interleave bridgeless resonant converter topology and an output passive ripple cancellation circuit was proposed. The proposed topology offered the benefit of reduced DC bus voltage, low input current ripple, more straightforward control, low capacitance and extremely low THDi of 0.48%. The ripple cancellation circuit reduced the output ripple voltage of about 27V to 431mV for a 400V, 7KW EV charger design case with the use of only a total of 2.2mF capacitance at the output stage.