A Novel Full-Bridge Step Density Modulation for Wireless Power Transfer Systems

Aiming for wireless power transfer (WPT) systems with high efficiency demands inverters under zero-voltage switching (ZVS) conditions. This letter presents a novel full-bridge step density modulation (FB-SDM) for WPT systems based on the step density averaging principle, which can achieve full-range ZVS operation. Compared with existing ZVS modulation schemes, such as pulse density modulation and hybrid frequency pacing, the proposed modulation scheme has the ability of balancing power device losses and the minimum low frequency output fluctuation. Simulation and experimental results prove that FB-SDM is one of the most potential ZVS modulation schemes for WPT systems.