A Single- and Three-Phase Grid Compatible Converter for Electric Vehicle (EV) On-Board Chargers

This paper proposes a voltage-source converter for an on-board Electric Vehicle (EV) charger which is compatible with both the single- and three-phase (1-ϕ and 3-ϕ) grids. The classic 3-ϕ active AC-DC rectifier circuit is used for both the 1-ϕ and 3-ϕ connection, but a new control scheme and LCL filter are designed to address the double-line frequency power pulsation issue caused by a 1-ϕ grid without using bulky DC capacitors. The third leg of the circuit is utilized to control the power pulsation in conjunction with stored energy in the LCL filter between the grid and charger rectifier. Neither additional active nor passive components are required. For the 3-ϕ connection, the rectifier is under balanced operation; when connected with the 1- ϕ grid, all three legs are controlled cooperatively as a 3-ϕ rectifier but under unbalanced operation to recreate the 1-ϕ voltage. Hence advantages from the 3-ϕ rectifier such as space vector pulse width modulation (SVPWM) and Y/Δ transformation can be utilized to increase utilization of DC-link voltage and filter capacitance respectively. The operation principle, control, and LCL filter design are reported and validated by both simulation and experiments of a 3-kW porotype.This work was supported by Innovate UK (TS/R016968/1)