A Noninvasive Online Monitoring Method of Output Capacitor's C and ESR for DCM Flyback Converter
A Noninvasive Online Monitoring Method of Output Capacitor's C and ESR for DCM Flyback Converter
复制标题
DCM反激变换器输出电容C和ESR的无创在线监测方法
DOI：
10.1109/tpel.2018.2868564
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发表时间：
2019-06-01
影响因子：
6.7
通讯作者：
Chen, Jienan
中科院分区：
文献类型：
--
作者：
Yao, Kai;Li, Hui;Chen, Jienan
在电力电子系统中，电解电容器（E-Cap）被广泛使用，其性能退化可以通过电容（C）和等效串联电阻（ESR）的变化来反映。提出了一种新的断续导通模式（DCM）反激变换器输出电解电容C和ESR在线监测方案。分析了瞬时电容电压与其它参数之间的数学关系，提出了基于多点采样和最小二乘法的待定系数方案。另外，考虑到高纹波电流的特殊性以及由此产生的电压纹波变化范围，特别是随温度的变化，提出了一种具有可变放大系数和负电压消除的反纹波电压隔离放大器，使数字信号处理器易于识别温度变化。该方案是无创的，因为只需要采样电压信号，不需要电流传感器。搭建了一台实验样机，并进行了实验验证，实验数据与LCR测量仪测量结果基本一致。
In a power electronics system, an electrolytic capacitor (E-Cap) is widely used, whose performance degradation can be reflected by the change of capacitance (C) and equivalent series resistance (ESR). This paper proposes a new online C and ESR monitoring scheme for the output electrolytic capacitor in a discontinuous conduction mode (DCM) flyback converter. The mathematical relationship between the instantaneous capacitor voltage and other parameters is analyzed and then the scheme of undetermined coefficients based on the multiple-spot sampling and least square method is further proposed. In addition, considering the particularity of high ripple current and the resultant voltage ripple variation range, especially with the temperature, an inverse ripple voltage isolation amplifier with variable amplification factor and negative voltage elimination is put forward so as to make digital signal processor identify the temperature change easily. The proposed scheme is noninvasive as only voltage signals need to be sampled and no current sensor is necessary. A prototype is built and the experiments are made to verify the effectiveness of the proposed method, from which the data are in accordance with the results measured by an LCR meter.