基于双向LLC谐振变换器的电池正负脉冲充电研究

发布时间：2018-05-06 22:08

本文选题：动力电池 + 快速充电　；参考：《西安理工大学》2017年硕士论文

【摘要】：LLC谐振变换器为软开关型电路拓扑,可实现逆变开关管的零电压开通与整流开关管的零电流关断,开关频率可以设计的很高,且变换器能实现高效高功率密度的双向工作。为了提高动力电池充电设备的充电效率及速度,本课题对基于全桥LLC谐振的双向DC-DC变换器进行了研究,重点分析了 LLC谐振拓扑,对脉冲充电方法、模糊充电方法进行了仿真设计和仿真验证。具体从以下方面开展了工作:首先针对提高电动汽车动力电池充电速度的问题,分析了动力电池的快速充电机理并对现有的快速充电方法的优缺点进行研究,对充电过程中不可避免的极化现象进行分析,本文采用正负脉冲充电来去极化;对提高变换器的充电效率问题,针对双向DC-DC拓扑电路并结合谐振拓扑的软开关特性,采用正负脉冲中短暂的放电负脉冲来去极化,提高电源利用率且缩短了总的充电时间;以双向全桥LLC谐振电路作为主电路,提出了以平滑脉冲充电曲线为改进目的的新型双向全桥LLC拓扑结构。另外,分析了双向全桥LLC基本构成网络,建立了稳态数学模型,研究了谐振槽参数变化对变换器增益特性的影响,研究了正负脉冲充电方法的移相控制和电压电流双闭环控制策略。在Simulink仿真环境下,建立双向全桥LLC谐振变换器的仿真模型,进行了开、闭环情况下的正负脉冲充电仿真,验证了改进后拓扑结构能平缓脉冲充电电流,脉冲充电能量可回馈及充电所具有的快速性。考虑到电池离散性和非线性等特点,采用模糊控制,建立了电池模糊充电的Simulink仿真模型,仿真表明了模糊控制相比于传统PI控制的优越性。其次,采用DSP的TMS320F28335芯片作为全桥LLC谐振变换器的主控芯片,进行了数字变换器的设计,计算并选择主电路元器件,设计了控制电路和部分软件的流程。最后利用simulink-DSP联合调制的Real-Time Workspace和CCS配置,在DSP中进行部分程序的调试。
[Abstract]:LLC resonant converter is a soft switching circuit topology. It can turn on zero voltage of inverter switch and switch off zero current of rectifier switch. The switching frequency can be designed very high, and the converter can realize high efficiency and high power density bi-directional operation. In order to improve the charging efficiency and speed of the power battery charging equipment, this paper studies the bi-directional DC-DC converter based on full-bridge LLC resonance, especially analyzes the LLC resonant topology, and discusses the pulse charging method. The fuzzy charging method is designed and verified by simulation. The main work is as follows: firstly, aiming at the problem of improving the charging speed of electric vehicle power battery, the mechanism of rapid charging of power battery is analyzed, and the advantages and disadvantages of the existing rapid charging methods are studied. The inevitable polarization phenomenon in charging process is analyzed in this paper, positive and negative pulse charging is used to depolarization, and to improve the charging efficiency of the converter, the bi-directional DC-DC topology circuit and the soft switching characteristics of resonant topology are combined. The short discharge and negative pulses in the positive and negative pulse are used to increase the power utilization rate and shorten the total charge time, and the bidirectional full-bridge LLC resonant circuit is used as the main circuit. A novel bi-directional full-bridge LLC topology is proposed for the purpose of smoothing the pulse charging curve. In addition, the basic network of bi-directional full-bridge LLC is analyzed, the steady state mathematical model is established, and the influence of resonant slot parameters on the gain characteristics of the converter is studied. The phase shift control and voltage and current double closed loop control strategy for positive and negative pulse charging are studied. In the Simulink simulation environment, the simulation model of bi-directional full-bridge LLC resonant converter is established, and the positive and negative pulse charging simulation is carried out under the condition of open and closed loop. It is verified that the improved topology can smooth the pulse charging current. Pulse charging energy can be fed back and charged quickly. Considering the characteristics of battery discreteness and nonlinearity, the Simulink simulation model of battery fuzzy charging is established by using fuzzy control. The simulation results show that the fuzzy control is superior to the traditional Pi control. Secondly, the DSP TMS320F28335 chip is used as the main control chip of the full-bridge LLC resonant converter. The digital converter is designed, the main circuit components are calculated and selected, and the control circuit and part of the software flow are designed. Finally, part of the program is debugged in DSP with the configuration of Real-Time Workspace and CCS modulated by simulink-DSP.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46;TM910

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