Evaluation of the Impact of Small Signal Models on the Control Strategies Performances of a Series-Series Compensated Wireless System

In this paper, the Extended Describing Function Method (EDF) is applied to a resonant DC/DC converter in inductive Wireless Power Transfer (WPT) systems, to derive its Small Signal Model (SSM). A check of the reliability of SSM is done with different tests in Simulink environment. The SSM is then used to tune a Proportional-Integrative-Derivative (PID) controller for the regulation of the resonant converter. Two different closed-loop control strategies, based respectively on the switching frequency and the duty cycle regulations, are proposed and investigated. Finally, the full system converter-control is numerically tested in Simulink environment under multiple working conditions, analyzing how the SSM use can influence the control strategies performances.