LLC谐振变换器损耗分析与效率优化

发布时间：2018-06-09 22:35

本文选题：LLC谐振变换器 + 损耗计算　；参考：《北京交通大学》2017年硕士论文

【摘要】：随着电力电子技术的飞速发展,高输入电压、大变比、高开关频率的变换器已经广泛应用到各个领域。同时,由于LLC谐振变换器在提高开关频率、减小开关应力和开关损耗、提高变换器效率等方面的明显优势,使用性广和发展空间大,因此使其成为了研究热点之一。本文是基于四变压器输入串联输出并联LLC谐振变换器电路,以高压输入低压输出的实际应用为背景,对变换器主要元器件的损耗进行详细分析,给出损耗数学模型,并通过平面变压器的优化设计减少损耗,提高变换器效率。首先,利用电磁场仿真软件ANSYS Maxwell和ANSYS Simplorer对四变压器输入串联输出并联LLC电路及其中的平面变压器进行3D建模和仿真。完成平面变压器的优化设计工作,对四种对称交叠结构的PCB铜绕组进行比较分析,根据电流密度和铜损的仿真结果,得到最优的交错并联PCB绕组;对四种结构不同的磁芯结构进行比对分析,根据磁场分布和铁损的仿真结果,得到最优的中柱双气隙磁芯。其次,文中在变换器损耗构成分析计算的基础上,利用ANSYS Q3D对寄生参数进行提取,并通过分析各个寄生参数对变换器的影响进行相关的优化,并完成对结果的验证。最后,通过一台输入800V-1000V,输出25V的4kWDC/DC变换器,对文中理论计算和仿真分析进行验证,证明理论分析的正确性及仿真模型的研究意义,同时证明了本文所采用的效率提升措施的有效性。
[Abstract]:With the rapid development of power electronics technology, high input voltage, large conversion ratio and high switching frequency converters have been widely used in various fields. At the same time, the LLC resonant converter has many advantages, such as increasing the switching frequency, reducing the switching stress and loss, and improving the efficiency of the converter, so it has become one of the research hotspots. This paper is based on the input series output parallel LLC resonant converter circuit of four transformers. Based on the practical application of high voltage input and low voltage output, the loss of the main components of the converter is analyzed in detail, and the mathematical model of loss is given. Through the optimization design of the plane transformer, the loss is reduced and the efficiency of the converter is improved. Firstly, the electromagnetic field simulation software ANSYS Maxwell and ANSYS Simplorer are used to model and simulate the input and output parallel LLC circuits of four transformers and their planar transformers. The optimization design of planar transformer is completed. Four kinds of symmetrical overlapping structure of PCB copper windings are compared and analyzed. According to the simulation results of current density and copper loss, the optimal staggered parallel PCB windings are obtained. Four magnetic core structures with different structures are compared and analyzed. According to the simulation results of magnetic field distribution and iron loss, the optimal medium column double air gap core is obtained. Secondly, based on the analysis and calculation of converter loss composition, the parasitic parameters are extracted by ANSYS Q3D and optimized by analyzing the influence of each parasitic parameter on the converter, and the results are verified. Finally, a 4kW DC / DC / DC converter with an input of 800V-1000V and an output of 25V is used to verify the theoretical calculation and simulation analysis, which proves the correctness of the theoretical analysis and the significance of the research on the simulation model. At the same time, the effectiveness of the efficiency improvement measures adopted in this paper is proved.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM46

【参考文献】