Low-Frequency Pulse Control for Self-Oscillation-Based Resonance Tracking of Wireless Power Transfer Systems

Self-oscillation-based resonance tracking is an effective solution to address the real-time detection issues of resonance states in wireless power transfer (WPT) systems with high efficiencies. Conventional self-oscillation implementations by designing equivalent negative resistances are costly and complicated. To this end, two types of low-frequency pulse (LFP) control in achieving transmitter-side current self-oscillation via the voltage pulse charging, are proposed in this article. One is a feedback-free LFP control, which has the merits of negligible delay and lower costs. The other is a zero-current switching (ZCS)-based LFP control, which performs higher efficiency with soft switching. Experimental results verify the effectiveness of both controls in tracking the outputs accurately and superior performance than the conventional control. The empirical results also demonstrate the pros and cons of both controls and validate that the proposed feedback-free LFP control is more suitable for fast dynamic WPT systems, while the ZCS-based LFP control is more suitable for efficient WPT systems.