A Multireceiver Wireless Power Transfer System Using Self-Oscillating Source Composed of Zero-Voltage Switching Full-Bridge Inverter

Nowadays, much effort focuses on research for the multireceiver wireless power transfer (WPT) system based on magnetic resonance. However, its output characteristics are significantly deteriorated by the variation of transfer spacing, loads, and cross-couplings, which exerts harmful effects on the performances of cascading bucks before loads if needed. Inspired by the work of a single-receiver WPT system based on the parity time symmetric model, in this article, the self-oscillating source is first applied to the multireceiver WPT system to tackle these drawbacks. Based on the coupled-mode theory, the proposed system's modeling is established and deduced to analyze its performance. The model analysis shows how the system can achieve zero-voltage switching simply via choosing the minimum dead time and leading time whose calculation method is provided. Meanwhile, a transmitting coil for a uniform magnetic field is designed to improve the free-positioning performance. The analysis is validated on a 36-W prototype, including the effects of the variation of transfer spacing, cross-couplings, and loads on the output characteristics, efficiency, and operating frequency. The proposed system is demonstrated to provide a much more robust power transfer than the conventional magnetic-resonant multireceiver WPT system, which helps extend the transfer distance and improve the system efficiency.