A closed loop controlled bidirectional contactless grid interface with a soft DC-link

Abstract

Bidirectional contactless grid interfaces are gaining popularity as an alternative to conventional hardwired interfaces in vehicle-to-grid (V2G) and grid-to-vehicle (G2V) applications. However, such systems typically employ a large input inductor as well as a large and expensive electrolytic DC-link capacitor, which compromises the reliability of the entire system. Although, back-to-back converter (BTBC) based bidirectional contactless grid interfaces with a variable or soft DC-link have been recently proposed as an alternative, the total harmonic distortion (THD) associated with grid currents of the BTBC based system exceeds the acceptable limits set by standards. As a solution, this paper proposes a closed loop controlled bidirectional contactless interface that employs a small input inductor, a small DC-link capacitor, and a grid converter operated at low frequency, for grid integration. The feasibility of the proposed system is validated through simulations of a 1 kW simulation model.