Research On Properties And Sensitivity Of Compensation Topologies In Wireless Power Transfer System

Wireless Power Transfer(WPT)systems have the advantages of safety,aesthetics,and saving human and material resources compared with traditional conductive power supply technologies.With the development of high-frequency power conversion technology,WPT technology has gained wide attention.In WPT systems,a certain amount of reactive power loss is generated during the operation of the system due to the availability of a certain number of passive components.By increasing the compensation topology and operating at resonant frequencies,it contributes to reduce the system circulating losses and improve the power factor,which in turn improves the overall transmission efficiency and power transfer capability of the IPT system.In addition,the parameters and configuration of the compensation topology vary widely in their effects on the transmission characteristics of the system.Therefore,the parameter selection and configuration methods of the compensation topology are crucial.Aiming at studying second and higher order compensation topologies for WPT covering Inductive Power Transfer(IPT)and Capacitive Power Transfer(CPT)systems,and providing design guidelines for various types of compensation circuits for addressing the common and inevitable issues arising from wide variations of coupling and compensation parameters,a systematic and rapid design guide for various types of compensation circuits is presented in this thesis to solve the problem of unavoidable effects on system performance due to fluctuations of coupling and compensation parameters in different environments.To offer direct insights into the choice of appropriate compensation topologies and their relationship with performance,a unified T-type two-port network model for IPT and CPT converters is first presented in this thesis.General transfer characteristics and corresponding operating conditions of the presented T-model IPT and CPT converters are summarized.On this basis,all possible second-order compensation topologies are systematically analyzed in depth to lay the theoretical foundation for further analysis of diverse compensation networks.A systematic extension of the basic second-order compensated IPT and CPT converters is then presented for achieving load-independent current(LIC)or load-independent voltage(LIV)output,to higher order compensated converters through adding an inductor or capacitor at the input or output side.Conditions on the parameters to achieve the required output performance are given.Then,the system’s sensitivity to various parameters’ fluctuation is analyzed.Results from sensitivity analysis provide a convenient design guide for selecting parameters and compensation topologies to achieve the required LIV and LIC operation for IPT and CPT systems with fewer design constraints.Moreover,the analysis effectively reveals the roles of extra input-side or output-side inductors and capacitors in making the whole system less sensitive,and hence provides a fast understanding of the choice of various compensation circuits for applications addressing wide ranges of coupling and compensation parameter values.In order to exemplify the advantages of various compensation topologies of WPT systems and the applications of the above design,the parametric design and system output stability studies of IPT and CPT systems are carried out,and the diversity of load types and operating conditions are analyzed in depth.The conclusions of the topology analysis and design methods of IPT and CPT are validated.For implant medical applications,the detailed design of the power supply systems for two load types,Left Ventricular Assist Device(LVAD)and Electroactive Polymer(EAP)film,using IPT is presented,The topology optimization method is proposed.The IPT and CPT systems are designed for aerospace applications,and the optimal compensation topology design is obtained by revealing the influence of external and self-influencing factors on the output,with respect to the fluctuation of system parameters caused by the special environmental changes.Corresponding experimental platforms are designed and built for each scenario to test the capability of different compensation topologies for the system output stability under different conditions,and to verify the relationship between compensation topology and load and the effectiveness of the design method.