New technique for inductive power transfer using a single controller

Inductive power transfer (IPT) technology has become a preferred technique for supplying contactless' power to numerous applications, ranging from microwatt bio-engineering devices to high-power battery charging systems. Typical IPT systems employ two separate controllers, one on the powering or primary side and the other on the receiving or pick-up side of the system, to facilitate contactless power transfer across an air-gap in an efficient and controllable way. This study presents a new IPT control technique, which requires only a single controller, located on the primary side, to effectively regulate the output voltage, which in turn controls the amount of 'contactless' power delivery to the pick-up side. The proposed technique uses only the variation in phasor relationship of circuit variables on the primary side to accurately regulate the output voltage or power without any wired or wireless feedback from the secondary side. Theoretical analysis and simulated results are presented, with experimental measurements of a prototype IPT system, to validate the viability of the proposed technique for IPT systems with constant magnetic coupling and single pick-ups. In contrast to existing IPT systems, the proposed IPT system with only a single controller is low in cost, more efficient, and thus can be considered as an attractive choice for many applications.