LCL Pickup Circulating Current Controller for Inductive Power Transfer Systems

This paper proposes a fast switching control topology for a series–parallel-tuned LCL pickup for inductive power transfer systems. This topology employs a similar idea to traditional controlled rectifiers that regulate the average output current through the rectifier. The proposed topology is able to provide continuous power regulation and smooth power transitions between the fully ON and fully OFF state. Due to the way in which the circuit operates, the proposed controller necessarily introduces additional reflected reactive power back onto the primary power supply. A steady-state analysis is presented enabling this reflected real and reactive power to be investigated and compared against SPICE simulations. These results are further verified by practical measurements on a 1.5-kW 300-V dc output pickup controller prototype which achieves an efficiency of 95% at full load and is still above 85% when operating at one third of its rated power.