摘要电解电容是电源系统中很容易失效的部分，电容性能以及参数的退化会降低系统的可靠性。为了能够预测开关变换器的寿命，监测其等效串联电阻和电容的变化就变得尤其重要。针对连续导通模式下反激变换器输出电容的等效串联电阻和电容提出一种新的非侵入式在线监测方案进行研究，通过理论分析掌握电解电容等效串联电阻和电容的测量方法，通过仿真分析，对电容参数监测的方法进行验证。84687

通过对输出电压的交流分量和直流分量进行分析，结合连续导通模式下电容电流的表达式，建立等效串联电阻和电容的模型以便实时在线计算，设计出监测电解电容的在线系统。该方案只需要采样脉冲宽度调制信号和三个不同时刻的输出电压，不会改变反激变换器的电气结构，也不需要电流传感器。可以监测出不同工作状态下的等效串联电阻和电容，实验结果和误差分析验证了监测方法的有效性。

毕业论文关键词  电解电容 等效串联电阻和电容值 在线监测 反激变换器 电压纹波

毕业设计说明书外文摘要

Title     A online monitoring method of capacitor’s ESR and   C for continuous conduction mode  Flyback converters 

Abstract Electrolytic capacitor power circuits is very easy to fail part, capacitive properties and parameters of the degradation will reduce the reliability of the system 。In order to be able to predict the switch life of the converter,monitor its equivalent series resistance and capacitance change becomes especially important。 A new novel online monitoring method of capacitor’s equivalent series resistance and capacitance for continuous conduction mode Flyback converters is proposed in this paper。 Master electrolytic capacitor equivalent series resistance and capacitance measurements by theoretical analysis and simulation analysis thus the capacitance parameter monitoring method validation。

Based on the ac and dc component of capacitor voltages and the constitution of capacitor currents in Continuous conduction mode, the calculation model is founded, then the online monitoring system of electrolytic capacitors is built 。This requires only the sampling pulse width modulation signal and the output voltage of the three different times 。The method is effective for the Flyback converter operating in different conditions without changing the electrical structure and needs no current sensors。 It can be detected under different working conditions of equivalent series resistance and capacitance，error analysis and experimental results demonstrate the effectiveness of monitoring methods。

Keywords  electrolytic capacitor  equivalent series resistance and capacitance   online identification  Flyback converter  voltage ripple 

目   次

1 绪论 1

1。1 研究工作的目的 1

1。2 研究工作的范围 1

1。3 对前人工作的评述 1

1。4 工作的研究设想 1

1。5 工作的研究方法 1

1。6 工作的实验设计 1

1。7 工作的预期结果 2

1。8工作的意义 2

2 Flyback变换器主电路分析 3

2。1 Flyback变换器主电路 3

2。2 Flyback变换器主电路波形 3

2。3 Flyback变换器主电路Q导通分析