A Simplified Dynamical Model for Tuned Wireless Power Transfer Systems

TL;DR

This paper introduces a simplified dynamical model for tuned wireless power transfer systems that reduces complexity by decomposing the system into controllable and uncontrollable parts, validated through experiments.

Contribution

The paper presents a novel, simplified dynamical model for tuned WPT systems, enabling easier analysis and control design by focusing on the controllable component.

Findings

The simplified model accurately describes the system at the tuned condition.

Experimental validation confirms the model's effectiveness in time and frequency domains.

The uncontrollable part exponentially converges to zero and can be ignored.

Abstract

Dynamical models of wireless power transfer (WPT) systems are of primary importance for the dynamical behavior studies and controller design. However, the existing dynamical models usually suffer from high orders and complicated forms due to the complex nature of the coupled resonances and switched-mode power converters in WPT systems. This letter finds that a well-tuned WPT system can be accurately described by a much simpler dynamical model. Specifically, at the tuned condition, the existing dynamical model can be decomposed into two parts. One is controllable and the other one is uncontrollable. The former should be considered in the modeling while the latter can be ignored because it always exponentially converges to zero. For illustration, the recently proposed zero-voltage-switching full-bridge pulse-density modulation WPT system is modeled as an example since such a system can efficiently operate at the tuned condition with soft switching and control capabilities. The derived model was verified in experiments by time-domain and frequency-domain responses.