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

摘要

This article proposes a voltage-source converter for an on-board electric vehicle charger, which is compatible with both the single- and three-phase (1-phi and 3-phi) grids. The classic 3-f active ac-dc rectifier circuit is used for both the 1-phi and 3-phi connections, but a new control scheme and LCL filter are designed to address the double-line frequency power pulsation issue caused by a 1-phi 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-phi connection, the rectifier is under balanced operation; when connected with the 1-phi grid, all three legs are controlled cooperatively as a 3-phi rectifier but under unbalanced operation to recreate the 1-phi voltage. Hence, advantages from the 3-phi rectifier, such as space vector pulsewidth modulation and Y/Delta 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.