• Proposes a novel fixed-frequency Zero Phase Angle (ZPA) compensation strategy for wireless power transfer (WPT) systems using a Nonlinear Capacitor (NC). • Achieves rapid dynamic recovery of ZPA within 5 ms (load change) and 20 ms (coupling change), ensuring stable and energy-efficient operation. • Enables ultra-low additional power loss (only 0.79 W) and minimal average efficiency degradation (0.3%) compared to the ideal resonant state. • Features a lightweight, primary-side-only compensation structure, eliminating the need for secondary-side modifications for practical deployment. • Contributes to enhanced energy efficiency and system robustness in WPT applications, directly supporting the development of more reliable and sustainable wireless charging solutions. Wireless power transfer (WPT) systems are essential for modern electronic platforms, yet their efficiency is highly sensitive to parameter detuning, which disrupts the critical Zero Phase Angle (ZPA) input condition, leading to reduced power factor and increased losses. To address this issue without altering the operating frequency, this paper proposes a fixed-frequency ZPA compensation strategy based on a Nonlinear Capacitor (NC). By dynamically adjusting the phase shift angle of the NC to offset parameter deviations in real-time, the system rapidly recovers the ZPA state. Experimental results demonstrate that the proposed system restores ZPA within 5 ms under load variations and 20 ms under coupling changes, with an ultra-low additional power loss of 0.79 W and an average efficiency degradation of only 0.3% compared to the ideal resonant state. Compared with mainstream compensation technologies, this scheme achieves an optimal balance among lightweight design, dynamic response, and energy efficiency, offering a low-complexity, cost-effective solution for stable WPT operation.
Yang et al. (Fri,) studied this question.