Modeling and advanced control of wireless power transfer system with Z-source inverter

In many practical applications of wireless power transfer (WPT) system, high power transmission efficiency is required and has been widely studied as an important issue. This paper presents and analyzes a Series-Parallel compensated WPT system with a Z-source inverter network inserted. To obtain higher efficiency, asymmetrical voltage-cancellation (AVC) control is applied and the ZVS operation is achieved. The AVC control algorithm should also be modified to help Z-source inverter to realize voltage boosted and fully utilize the null state existed in the AVC control. On account of the ZVS operation, the power factor of the system decreases inevitably, but it decreases less in Series-Parallel compensated topology than in Series-Series compensated topology. To verify the feasibility of the proposed method, a small-signal model is fully analyzed, and a controller is designed to help to realize AVC control. Finally, a simulation model is established and the result agrees with the analysis.