Triple Phase Shift Modulation Scheme for Bidirectional Wireless Power Transfer Systems With Efficiency Maximization

This brief proposed an optimal and unified triple phase shift (TPS) control strategy for some widely-used bidirectional inductive power transfer (BIPT) systems. The phase shift angles of the full-bridge converters at both the primary and secondary sides, as well as that between them, are developed and regulated dynamically to get zero-voltage switching (ZVS) operation over the full range of power level. Additionally, the resonant tank current is optimized to minimize the system conduction loss. Therefore, the proposed BIPT system will benefit with its efficiency maximization in terms of possible voltage gain (i.e., Buck, Boost, and Unity). A series-series (S-S) compensated BIPT system is taken as an example and a 250W GaN-based experimental prototype is built to verify the proposed modulation scheme. Its peak efficiency is up to 95.1% and increased by 1.9% compared with the conventional TPS control method.