Decomposition and Synthesis of High-Order Compensated Inductive Power Transfer Systems for Improved Output Controllability

High-order compensation provides more design freedom for inductive power transfer systems and can help improve output voltage/current controllability. This paper develops a simplified decomposition and synthesis method for high-order-compensated inductive power transfer systems. It can achieve load-independent (LI) output under coupling variation, and easily fulfill the various charging requirements, such as constant voltage or constant current. The coupling independent resonance is ensured by using the induced source model, and the whole resonant tank is effectively decomposed as three parts. The power transfer characteristics are discussed for each part, and the requirements for LI output and zero phase angle (ZPA) operation are combined to generate the compensation candidates for both sides. Two families of topologies are synthesized for four kinds of conversions, i.e., voltage to voltage, voltage to current, current to voltage, and current to current. Meanwhile, the proposed method dramatically simplifies the evaluation for the influence of the coil equivalent series resistors on the transfer function and efficiency. These resistor-caused effects are quite different for two families of topologies. Finally, a 6.78-MHz system with 10-W output is designed to verify the difference between two-family topologies.