Pulsed Self-Oscillating Nonlinear Systems for Robust Wireless Power Transfer

TL;DR

This paper introduces a robust wireless power transfer system that uses pulsed self-oscillation and feedback design to automatically adapt to load and position changes without additional tuning circuitry, achieving high efficiency.

Contribution

The authors propose a novel self-oscillating WPT system with pulsed oscillations that automatically maintains optimal power transfer without extra control circuits.

Findings

System achieves robustness under load and position variations

Experimental results match analytical models

Efficient power transfer comparable to wired connections

Abstract

While wired-power-transfer devices ensure robust power delivery even if the receiver position or load impedance changes, achieving the robustness of wireless power transfer (WPT) is challenging. Conventional solutions are based on additional control circuits for dynamic tuning. Here, we propose a robust WPT system in which no additional tuning circuitry is required for robust operation. This is achieved by our systematically designing the load and the coupling link to be parts of the feedback circuit. Therefore, the WPT operation is automatically adjusted to the optimal working condition under a wide range of load and receiver positions. In addition, pulsed oscillations instead of single-harmonic oscillation are adopted to increase the overall efficiency. An example system is designed with the use of a capacitive coupling link. It realizes a virtual, nearly-ideal oscillating voltage source at the load site, giving efficient power transfer comparable to that of the ideal wired-connection scenario. We numerically and experimentally verify the robustness of the WPT system under the variations of load and coupling, where coupling is changing by our varying the alignment of aluminum plates. The working frequency and the transferred power agree well with analytical models. The proposed paradigm can have a significant impact on future high-performance WPT devices. The designed system can also work as a smart table supporting multiple receivers with robust and efficient operation.