Constant Voltage/constant Voltage Wireless Charging System Based On The TS/FS Variable Structure Compensation Network Of Transmitting Terminal

Lithium batteries are favored by new energy markets such as electric vehicles because of their unique characteristics and advantages.However,the existing charging methods of lithium batteries are mostly contact charging,and the charging process cannot be automated and intelligent.If the non-contact charging of the lithium battery can be realized based on the WPT technology,It will greatly improve the flexibility and safety of lithium battery charging.The constant current and constant voltage output of the wireless charging system is the key to realize the non-contact charging of the lithium battery,and the constant output characteristics of WPT system are closely related to its compensation network structure.For this reason,the CC and CV characteristics of the WPT system compensation network will be analyzed in depth.It is great significance to promote the development of WPT technology.The main innovation of the paper is to propose a construction method of WPT system composite compensation network.According to the output characteristics of Series-Series compensation and high-order passive compensation networks,the method combines them organically to form a series of composite compensation WPT topologies with CC and CV outputs.Then,a constant voltage/constant current wireless charging system based on the TS/FS variable structure compensation network at the transmitting terminal is proposed,which verifies the feasibility of constructing the compensation network method.This paper mainly studies from the following three aspects:(1)Composite compensation network construction methodThe first aspect deeply analyzes the constant output characteristics of the Series-Series(S-S)compensation circuit under different inputs.Based on this,the construction mechanism of the composite compensation network is introduced in detail,and summarized the constant output and the ZPA restriction.(2)TS/FS-S variable structure compensation network constant current / constant voltage charging systemThe mathematical model of output gain and input impedance for the two charging modes of the system is established.This part specifically analyzed the constant output of the system and ZPA restriction,and gives the system parameter design method.Finally,the experimental prototype was established.It can realize that the load CC output and CV output float within 1.9% and 3.1% when the load changes from 5? to 200?,and the system works in the Zero Phase Angle state.(3)Stability analysis and control of variable structure WPT systemFirstly,the mathematical model about the influence of internal resistance on system output is established.Then,the problem of deviation of system output gain caused by mutual inductance fluctuation is analyzed.Finally,the output voltage of inverter is changed by switching duty cycle control to ensure system output stability.