Analysis of Coupled-Coils

This chapter introduces a design-oriented analysis of various wireless power links driving a resistive load, which include the ideal coupled-coils, the coupled-coils with parasitic resistors, the coupled-coils with series-resonant primary and series-resonant secondary, and the coupled-coils with series-resonant primary and parallel-resonant secondary. The standard equation-pair of coupled-inductors is employed to analyze the above configurations to obtain (1) the reflected impedance of the secondary circuit detected at the primary side, (2) the link voltage gain and (3) the link efficiency. We label the analysis as design-oriented by presenting the equations with parameters arranged in a way that expose the physical meaning of the results and help with designing the coupled-coils more systematically and effectively.