Research On Positive And Negative Pulse Charging Of Battery Based On Bidirectional LLC Resonant Converter

LLC resonant converter for the soft-switching circuit topology can be realized in the inverter switch zero voltage switching and rectifier switch zero current off, the switching frequency can be designed very high, and the converter can achieve high efficiency and high power density of the two-way jobs. In order to improve the charging efficiency and speed of the charging equipment of the power battery, this paper studies the bidirectional DC-DC converter based on the full bridge LLC resonant, and analyzes the resonant topology of the LLC. The simulation design of the pulse charging method and the fuzzy charging method And simulation verification. Specific work has been carried out from the following:Firstly, aiming at the problem of increasing the charging speed of the battery, the principle of fast charging of the power battery is studied and the advantages and disadvantages of the traditional and the existing fast charging method are compared. The inevitable polarization phenomenon in the charging process is analyzed. In this paper, the positive and negative pulse charging is used to depolarize. In order to improve the charging efficiency of the converter, the common bidirectional DC-DC topology circuit is compared and analyzed.Combining the soft switching characteristics of the resonant topology, Pulse can be the battery energy back to the front capacitor to the polarization, improve power efficiency and shorten the total charging time; clear to two-way full bridge LLC resonant circuit as the main circuit;proposed a smooth pulse charging curve for the purpose of improved Two - way full bridge LLC topology. In addition, the analysis of two-way full-bridge LLC basic network structure,the establishment of its steady-state mathematical model to study the resonant tank parameters on the converter gain characteristics of the positive and negative pulse charging method of phase shift control and voltage and current double closed-loop control strategy The In the Simulink simulation environment, the simulation model of bidirectional full bridge LLC resonant converter is established, and the simulation of open and closed loop and positive and negative pulse charging is carried out. It is verified that the improved topology can smooth the pulse charging current, the pulse charge energy can be fed back and the The charging method is fast. Considering the characteristics of battery discretization and non - linearity, Simulink simulation model of fuzzy charging is established by fuzzy control. Simulation shows that the fuzzy control is superior to traditional PI control. Secondly, DSP TMS320F28335 chip is used as the master chip of full bridge LLC resonant converter. The design of digital converter is pulse charging current, the pulse charge energy can be fed back and the The charging method is fast. Considering the characteristics of battery discretization and non - linearity, Simulink simulation model of fuzzy charging is established by fuzzy control. Simulation shows that the fuzzy control is superior to traditional PI control. Secondly, DSP TMS320F28335 chip is used as the master chip of full bridge LLC resonant converter. The design of digital converter is discussed, and the parameters of the main circuit components are selected and designed. The control circuit and some software flow are designed. Finally, using simulink-DSP co-modulation Real-Time Workspace and CCS configuration, you can generate C language code without inputting the program, compile and debug in DSP, and verify the feasibility and correctness of RTW based on in-loop debugging scheme.