An Efficient Three-Port Partial Power Converter Based EV On-Board Fast Charger

Abstract

The objective of this work is to design and develop a new three port boost AC-DC converter which facilitates on-board fast charging for electric vehicles using partial power processing (PPP) at bidirectional DC-DC stage. As compared to conventional two-stage chargers with two port AC-DC and full-power processing (FPP) DC-DC converter, the three-port converter (TPC) ensures reduced voltage stress across the switches. This allows the converter operation at higher power without additional stress on devices while reducing the charging time. The PPP at DC-DC stage makes it highly efficient due to reduced power conversion stages. The proposed TPC is able to generate three levels of output voltage, which reduces the converter switching loss. The proposed TPC with PPC concept further minimizes the power losses as only a fraction of the power is processed by the DC-DC converter switches and components. Hence, the charger overall size and cost can be reduced while achieving significantly high efficiency as compared to conventional two-stage charger with FPP, even without soft-switching. The performance of proposed charger is validated under different operating conditions using MATLAB/Simulink based simulation model for 6.6 kW and scaled down-lab prototype for 1.5 kW.