一种在线式开关电源输出端电解电容监测方法

摘要

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 equiva⁃lent 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 theo⁃rem,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.%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。