An AC processing pickup for IPT systems

This paper presents a new type of Inductive Power Transfer (IPT) pickup which directly regulates power in AC form, hence producing a controllable high-frequency AC source. The pickup has significant advantages in terms of increasing system efficiency, reducing pickup size and lowering production cost compared to traditional pickups that also produce a controlled AC output using complex AC-DC-AC conversion circuits. The new AC processing pickup employs switches operating under soft switching conditions to clamp parts of the resonant voltage across a parallel tuned LC resonant tank to achieve power regulation over a wide load range. A complete IPT system using the AC processing pickup is tested on a 500 W lighting system and an efficiency of 96% is obtained when delivering 500 W to multiple resistive light bulbs.