Analysis, Design, and Optimization of LC/S Compensation Topology with Excellent Load-Independent Voltage Output for Inductive Power Transfer

Compensation circuit is vital for inductive power transfer (IPT) systems to achieve higher system efficiency, power density, and reliability. This paper proposes a novel compensation topology LC/S (primary inductor-capacitor and secondary series). The characteristic of load-independent voltage output (LIVO) is analyzed on the basis of LC (inductor-capacitor) and CL (capacitor-inductor) resonant tanks. The realization of zero voltage switching and reactive power demand are discussed by means of theoretical deduction and numerical simulation, aimed at balancing inductor current and capacitor voltage. The stress-based optimization method is also presented to further lower inductor current and capacitor voltage. Detailed steps to design a prototype fulfilling all performance requirements are given. A prototype is subsequently built according to these steps. A series of verification experiments is carried out. The output voltage only drops by 7.5% when the load decreases by half, implying a quite well characteristic of LIVO. The experimental results match well with the calculations, validating the rightness of the newly proposed parameter tuning method. An end-To-end efficiency (from dc input to dc output with all power loss incorporated) of 92.28% is achieved, showing a bright future for IPT technology.