Research Of High-voltage And High-power Wireless Power Transmission Technology

Wireless power technology(WPT)is a technology that does not need a conduction medium to perform electrical transmission.The technology eliminates the need for wire connec-tions between power sources and electrical equipment,and fundamentally solves a series of safety problems such as electric sparks and mechanical friction caused by contact charging.At present,for high-voltage and high-power scenarios,traditional single-input single-output WPT equipment often has problems such as excessive inverter input voltage,excessive bus current,and large heat loss of power devices.The medium-voltage DC distribution network is equipped with the development of high-power power electrical facilities such as large factories and ports,and the development of multi-level inverter technology,making the WPT equip-ment directly from the distribution network to high-voltage high-power DC power.Therefore,this paper takes WPT system as the research object,aims at high-voltage and high-power power transmission,takes series inverters and parallel rectifier bridges as the starting point,focuses on a series of issues that the WPT equipment is running in high-voltage power sce-narios.First of all,this paper proposes a series-input multi-to-one WPT topology,the parameter design method of the resonant loops and the transmission characteristics in both zero phase angle and non-zero phase angle states are studied by circuit analysis methods.At the same time,the synchronous design method of high-frequency series inverters was also studied.Synchronous operation of multiple high-frequency inverters is implemented by the master-slave control strategy.The feasibility of the system is verified under high-voltage and high-power conditions through experiments in this paper.At the same time,the input voltage equalization problem of the series-input multi-to-one WPT topology is studied.Considering the component parameters of each loop and the mutual inductances between the coils,the research method combining circuit analysis and simulation are adopted,the mechanism of the unbalanced input voltage of the series inverter has been explored,the input voltage expression equation of the series inverter in the series-input multi-to-one WPT topology is solved.In order to implement the series inverter input voltage equalization,this paper propose input voltage equalization strategies,and verifies the effectiveness of the strategies by simulation and experiment.Finally,the balance of the input voltage of the series inverter is realized.Furthermore,in order to optimize the topology of the series-input multi-to-one WPT topology,a series-input multi-to-one WPT topology based on multiphase transformer is pro-posed in this paper.The suppression effect of the multi-phase transformer on the input voltage of the series inverter is verified which fundamentally solves the problem of unbalanced input voltage in series inverters.Moreover,according to the characteristics of the multi-phase trans-former,a multi-to-one anti-offset WPT system was designed in this paper.The power transfer characteristics of the multi-to-one coils are studied,and the mutual inductance characteristics are analyzed when the relative position of the load side and the transmitted coil group changes.Besides,a multi-to-one coils adaptive working mode is proposed to effectively improve the anti-offset capability of the WPT system.Finally,for the problem of parallel rectifier bridge output current unbalanced in high-voltage and high-power WPT systems,based on the electrical characteristics of the multi-phase transformer,a parallel bridge topology with the multi-phase transformers is designed along with theoretical analysis and simulation.And the effectiveness of multi-phase trans-formers to solve the equalization problem of parallel joint bridge output current is verified.Combined with the series-input multi-to-one WPT topology,a series-input parallel-output many-to-many wireless power transfer system suitable for high-voltage and high-power sce-narios is proposed in this paper.Based on the simulation and analysis of the transmission channel,the transmission characteristics and parameter design methods of the series-input parallel-output many-to-many wireless power supply system are studied.