General Unified Analyses of Two-Capacitor Inductive Power Transfer Systems: Equivalence of Current-Source SS and SP Compensations

A general and systematic comparison of eight compensation schemes in the inductive power transfer system (IPTS) of single magnetic coupling and two capacitors is proposed in this paper. The characteristics of series-series (SS), series-parallel (SP), parallel-series (PS), and parallel-parallel (PP) compensation schemes for a voltage source or a current source are widely explored in terms of maximum efficiency, maximum power transfer, load-independent output voltage or current, magnetic coupling coefficient (k) independency, and allowance of no magnetic coupling (k = 0). Through comparative analyses using a general unified IPTS model, the current-source-type SS and SP are found to be superior to other compensation schemes in terms of the five criteria mentioned above, and they are found to have nearly the same efficiency, load power, and component stress characteristics for the same load quality factor. A design guideline for the current-source-type SS and SP is suggested and experimentally verified by a 200-W prototype of air coils at 100 kHz.