Research On Resonance Bidirectional Wireless Power Transfer System

In the field of wireless power transfer technology,Bidirectional Wireless Power Transfer(BD-WPT)technology not only has the advantages of safety,reliability,flexibility and convenience of one-way wireless power transfer technology,but also can realize peak cutting and valley filling optimization process for power grid and when electric vehicle is flexible load and distributed energy storage power supply,and improve the interaction with the power grid,so it has important social an d economic significance.However,the mature application of BD-WPT still has the problems of difficult control technology,high voltag e and current stress of coupling elements and difficult operation of soft switch.In order to solve the above problems,this paper mainly studies the optimization of control strategy and the optimization design of compensation network parameters.The main research contents are as follows:In this paper,the model of BD-WPT system with S-S,LCL-LCL and LCCLLCCL compensation topologies is analyzed by using the circuit theory,and the formulas of transmission power and efficiency are derived.The transmission performance of BD-WPT system with the above three topologies under the condition of open circuit and short circuit on the secondary side is compared and analyzed,and the system performance of LCCL-LCCL compensation topologies is obtained It is more suitable for fault tolerance and transmission of BD-WPT system.Secondly,taking the magnetic coupling resonant LCCL-LCCL BD-WPT system as the research object.Based on the dual phase-shifting control strategy,this paper proposes a dual phase-shifting optimization control strategy.By controlling and optimizing the range of power phase angle,the effective control of the system is realized,and the problems of constant power transmission,power flow direction conversion and size adjustment,synchronous operatio n control technology in the system are solved.The simulation model of BD-WPT system with dual phase-shifting optimal control strategy is built by using Simulink software.The simulation results show that the dual phase-shifting optimal control strategy has the advantages of good effectiveness,strong operability and relatively simple control structure.Aiming at the problems of large voltage and current stress of compensation elements and difficult operation of soft switch in the operation of the system,a compensation network is designed The voltage and current stress of the compensation element is only related to the value of the secondary side parallel compensation capacitor,and the soft switching operation of the system under low voltage and current st ress is only related to the value of the secondary side series compensation capacitor.The simulation analysis of the system model after the optimization of the compensation network parameters is carried out,and the simulation results prove the correctnes s of the theoretical analysis Considering that the parameters of the coupling coil and the load resistance,coupling coefficient and frequency of the main influence factors have a vital impact on the transmission performance of the system,the simulation a nalysis of the coupling coil and the transmission characteristics of the system are carried out respectively,and the corresponding conclusions are obtained.Finally,according to the circuit design of the system,a static resonant bidirectional wireless power transfer device is built.Within the allowable error range,the experimental results are basically consistent with the theoretical and simulation analysis,which verifies the feasibility and correctness of the dual phase-shifting optimal control strategy and the optimal design scheme of compensation network parameters.