面向可靠性的Buck输出侧LC滤波器设计

Reliability-oriented Design of LC Filter in Buck DC-DC Converter

目前Buck电路输出侧LC滤波器的设计方法为基于电压电流纹波、功率密度与成本的设计,但在可靠性要求较高的应用中,直流变换器寿命为评价直流变换系统性能的关键指标。在当前LC滤波器设计因素的基础上,从可靠性角度提出了一种LC滤波器的优化设计方法。首先研究了电感值与电容值对系统中电解电容发热的影响,再结合电解电容寿命模型,进一步分析了不同滤波器参数下的电解电容寿命,并根据电解电容寿命要求,设计了1 k W Buck直流变换器可靠性较高的LC滤波器参数。最后以Matlab仿真平台与1 k W Buck实验平台作为检验手段,对计算结果进行了验证。

State-of-the-art LC filter design of Buck DC-DC converter is based on the specifications of voltage and current ripples and constrains in power density and cost. Since lifetime is an important performance factor in reliability critical applications,this digest proposes a method to optimize the design of the LC filters from a reliability perspective among other considerations. It investigates the design freedom between the values of inductor and capacitors, the physical formation of the LC network, and the corresponding electro-thermal stresses of the selected capacitors. The outcome enables an optimized LC filter design to fulfill the required lifetime. The theoretical analysis and simulation study are presented which are verified by the experimental results from a Buck converter prototype.