Modelling and Control of Novel Bidirectional Single-Phase Single-Stage Isolated AC-DC Converter with PFC for Charging of Electric Vehicles

The small signal analysis of bidirectional single-phase single-stage AC-DC converter and its application for EV charging are presented in this paper. A unique control strategy for establishing soft switching without any additional circuit is developed utilizing the traditional state-space averaging technique. The small signal model in each mode of operation is presented. Using this model, current at the input of the ac side can be regulated to realize power factor correction (PFC) and also to regulate active and reactive power flow in either direction. Four quadrant operation of the converter can be utilized for improving the stability of the power grid. Controller designed using the derived small signal model is used to validate the operation as well as transition of the converter between V2G and G2V modes. Simulation results are presented to demonstrate four quadrant operation of the designed converter. Design of the converter, closed loop controller, and the results are presented for 1.5kVA converter.