Output power increase of a series-series compensated inductive power transfer system via asymmetric loading

This work implements an asymmetric loading rectification technique in an Inductive Power Transfer System (IPTS) intended for use in electric vehicle wireless chargers. Asymmetric loading is performed by a half-cycle short-circuit / half-cycle loading operation, in the secondary side of a series-series compensated IPTS. The aim is to reduce the value of the load resistance as reflected to the power supply, in order to increase the power intake from a given voltage source. Increase in the power provided to the battery is of great importance in wireless charging systems, as it decreases the duration of charging. Achieving it without intervention on the input voltage source is an additional advantage, since it decreases the number of converters used for the system. Simulations and experiments are carried out in a series-series compensated prototype IPTS for a variety of resistive loads. Results show a significant increase in the output power, especially for high resistance loads, in comparison with the conventional full wave rectification. Equivalent results are obtained by charging a 28.8 V, 20 Ah LiFePO₄ battery pack.