一种在线式开关电源输出端电解电容监测方法.docVIP

一种在线式开关电源输出端电解电容监测方法 　　摘 要： 开关电源中电容的性能退化是导致电源故障的重要因素，因此提出一种在线式的、针对BUCK拓扑的数字控制开关电源监测其输出端铝电解电容容量与串联等效电阻（ESR）的方法，实现了对电源中输出端电容性能退化的实时监测。在负载发生阶跃下降时，通过对电容电流进行积分，结合电荷守恒定理对电容值进行计算，进而基于电容充电过程中两端电压计算电容串联等效电阻的阻值。以STM32F4作为控制器对该方法进行了实验验证，其不仅能对电容值与ESR进行测量而且可以对电容性能退化进行实时监测。该方法算法复杂度低、硬件结构简单、误差较小，有较强的可行性。 　　关键词： 电容测量； ESR测量； BUCK变换器； 数字电源 　　中图分类号： TN710?34 文献标识码： A 文章编号： 1004?373X（2015）24?0148?04 　　An online monitoring method for output?end electrolytic capacitor of 　　switching mode power supply 　　LI Qi， YANG Biao， YU Hao， FENG Lian 　　（School of Information Engineering and Automation， Kunming University of Science and Technology， Kunming 650500， China） 　　Abstract： The performance degradation of the electrolytic capacitor in switching mode power supply is an important factor to result in power failure， so a method of monitoring the capacity of output?end aluminum electrolytic capacitor and series equivalent resistance （ESR） on line is proposed for the digital?controlled switching mode power supply in allusion to BUCK topology， which can realize the real?time monitoring to the performance degradation of the output?end capacitor. When the load occurs step decline， by integrating the current of the capacitor， the capacitance is calculated in combination with charge conservation theorem， and the ESR value of the capacitor is calculated based on the voltage in both ends in charging process of the capacitor. The method is verified by the experiment， in which STM32F4 is used as the controller. The results show that the proposed method can measure the ESR and capacitance， and monitor the performance degradation of the capacitor in real?time. The algorithm of the method has low complexity， simple hardware structure， little error and strong feasibility. 　　Keywords： capacitor measurement； ESR measurement； BUCK converter； digital power supply 　　0 引 言 　　开关电源是目前应用最广泛的电源，应用表明电解电容的寿命是开关电源寿命的主要瓶颈。在工作过程中电解电容等效电路模型中的串联等效电阻（ESR）会不断增大，容量下降[1]，使得开关电源输出纹波增加，甚至使电子、电气设备损坏，造成损失。目前对铝电解电容的失效机理与故