Characteristics Analysis of Series/Series Compensated IPT Converter With Adjustable Load-Independent Output Voltage

To simplify the control circuity, the output of the inductive power transfer (IPT) system is usually designed to be independent of load. However, since the physical parameters of the loosely coupled transformer explicitly appear in the analysis model used during the design process, the load-independent output inevitably relates to the transformer’s parameters, making the design procedure complicated and needs iterative process to meet both output requirement and transformer’s space constrain. In this paper, the derivation of the compensating parameters to achieve output voltage gain which is irrelevant to load and transformer’s parameters based on mathematical analysis is presented. Also, an implicit transformer model, in which the transformer ratio is irrelevant to physical parameters, is introduced to give an intuitive explanation of the compensating method. By changing compensation parameters, the output voltage of the basic S/S compensation can be adjusted according to different system requirements without redesigning transformer. The decoupling of IPT output and transformer’s physical parameters gives high freedom of transformer design. The criteria of adjustable voltage gain is revealed based on the mathematical analysis. Prototypes based on a single loosely coupled transformer are built to demonstrate the correctness of the theoretical analysis.