Self-Resonant Antisymmetric Planar Coil for Compact Inductive Power Transfer System Avoiding Compensation Circuits

Compensation circuits, the unavoidable components of the traditional inductive power transfer (IPT) systems for high efficiency, not only increase the circuit complexity, but also reduce the system reliability. Self-resonant coils are promising in capacitorless IPT systems. A high-efficiency novel antisymmetric planar coil (APC) is proposed to improve the performance of self-resonant coils. The APC consists of two antisymmetric planar windings that are arranged in two parallel layers, and exhibits an intrinsic parasitic series capacitor. Possessing the simplest configuration, the APCs IPT system is only composed of two APCs, an ac source and a load. Based on analysis and simulations, the design guidelines for developing transmitting and receiving APCs according to the maximum power transfer principle and the maximum energy efficiency principle with given voltage transfer ratio are derived, respectively. The novel APC, the corresponding compact IPT system and the design guidelines are validated by design examples with experimental tests and a demonstration. Avoiding the compensation circuits, the APCs IPT system has compact configuration, high reliability, and proves to be a good candidate in wireless power transfer applications.