A Matrix Converter-Based Bidirectional Contactless Grid Interface

Abstract

Bidirectional contactless grid interfaces based on inductive power transfer technology have shown substantial promise in vehicle-to-grid and grid-to-vehicle applications as an alternative to hardwired interfaces. Such a bidirectional contactless grid interface typically includes a two-stage power conversion in conjunction with a bulky and expensive dc-link capacitor and a large low-frequency inductor to generate voltages at high frequency from low-frequency utility grid. This paper proposes a matrix converter (MC) that directly produces voltages at high frequency from the utility grid to drive resonant networks of the bidirectional contactless interface. A comprehensive mathematical model that predicts the steady-state voltages and currents as well as the power drawn by the system is proposed to gain an insight into the operation of the proposed MC topology. Utilizing the mathematical model, a modulation strategy is also proposed to attenuate the undesirable harmonics in the grid current. Experimental results obtained from a 1-kW prototype system show excellent agreement with those obtained from the mathematical model, validating the practical applicability of the proposed approach. Experimental results of total harmonic distortion of grid currents are also presented to demonstrate the effectiveness of the proposed modulation strategy at attenuation of grid current harmonics.