Three-port ac-dc bidirectional converter with V2G reactive power support

This paper presents an isolated three-port ac-dc converter with vehicle-to-grid (V2G) reactive power capability. Port 1 of the proposed converter is interfaced with AC through a matrix converter while Port 2 and Port 3 are connected respectively to supercapacitor (SC) and battery. The SC can be charged by receiving active power from the AC grid, and can also provide reactive power to the AC grid when reactive power regulation is required. While the SC charges from the AC grid, the battery in port 3 is charged through the SC and does not charge directly from the AC grid. As such, the SC also serves as energy buffer and ensures pulsation-free power transfer to the battery. In addition, a tuned inductor-capacitor-inductor (LCL) resonant tank is used in the secondary and tertiary side of this converter to improve efficiency.