Resonant converter with coupling and load independent resonance for omnidirectional wireless power transfer application

Omnidirectional wireless power transfer (WPT) system has been studied recently due to its better user experience compared with directional WPT system. And this paper focus on resonant converter topologies study in omnidirectional WPT system. At first, three challenges of resonant converter design are identified: I. moving resonant frequency under variable coupling condition; II. voltage controllability under load change; III. complicated system control with coupling between multiple coils. CLCL-LC resonant converter is proposed to solve all the challenges and provide zero voltage switching (ZVS) operation for primary device at resonant frequency. A 6.78MHz CLCL-LC resonant converter for omnidirectional WPT system is built and tested.