Indirect Control Strategy of Secondary Current for LCC-Series Compensated Wireless Power Transfer System Based on Primary Current Closed-Loop Control

Abstract

In this article, the steady-state and transient characteristics and current control strategy of LCC-S compensated wireless power transfer (LCC-S-WPT) system with the battery as a load is researched in detail. It is proven that the steady-state secondary current is proportional to the primary inverter output current. The small-signal model of the LCC-S-WPT system based on the extended description function method is established. Based on the above theoretical analysis results, the indirect control strategy of the secondary current based on the primary current closed-loop control is accordingly proposed. And it is proven that the closed-loop system automatically eliminates the transient oscillation of the secondary current. Further, the parameters of the controller are designed to ensure the excellent dynamic performance and stability of the LCC-S-WPT system. Furthermore, a mutual inductance identification method based on the dual secondary current references is proposed to ensure the control accuracy of the secondary current. Finally, the correctness of the theoretical analysis and the feasibility of the proposed strategy are verified by experiments.