Step Density Modulation for Wireless Power Transfer Systems

Zero voltage switching (ZVS) techniques can significantly reduce the losses of power semiconductors in wireless power transfer (WPT) system. Hybrid frequency pacing (HFP) modulation is one of the most potential candidates to achieve ZVS for power regulation, but the principle of HFP is not intuitive enough and the implementation of HFP is a little bit complicated. This paper gives a radically new perspective on existing ZVS modulation for WPT system, and proposes a novel step density modulation (SDM) to regulate output power of WPT system. The simulation and experimental results proves that SDM has the same performance as HFP but the modulator structure of SDM is more simple.