Approximate Linearization of Rectifier Load in Wireless Power Transfer Systems

Abstract

This article presents an approximate linearization method for the rectifier load used in wireless power transfer (WPT) systems. The related complex non-linear relationship between the WPT load and rectifier input impedance is transferred to simple linear expressions through the proposed method, which will be helpful for system design and control. First, the equivalent circuit model is established considering WPT system with the uncontrolled diode rectifier and LCC compensation. Then, the complete expressions of the rectifier load equivalent impedance are obtained based on the model. Moreover, the monotonicity of the parameter relationships is discussed in order to clarify the linearization prerequisite. Furthermore, the linearization process is presented and the analysis indicates that it will be affected by the selected linearized point and the related WPT parameters. Finally, a WPT prototype is developed. The experiments and simulations have proved the effectiveness of the presented rectifier load analysis and its linearization method on the conditions of mutual-inductance, compensation parameter, and battery voltage variations.