【作者】 王鹏；

【导师】 殷春；

【作者基本信息】 电子科技大学 ， 工程硕士（专业学位）， 2021， 硕士

【摘要】 交流电源已经广泛应用于生活生产中各个领域,尤其大功率交流电源作为现代军事电子设备稳定运行的可靠保障,交流电源的可靠性研究显得尤为重要。作为电力电子系统关键功率器件之一,铝电解电容在交流电源中起到滤波、储能,平衡多级变换器之间能量差的作用,是交流电源稳定性的重要保障。然而在所有功率器件中铝电解电容失效率高达60%,铝电解电容的失效必定会使交流电源产生安全性问题,更甚者会对人们生命安全造成威胁。因此进行交流电源中的铝电解电容的可靠性问题研究,对提高交流电源的稳定性运行有着中重要意义。本文选择10KVA三相全桥逆变电源作为研究对象,首先建立其仿真模型观察直流母线铝电解电容波形信号,并对逆变器模块的失效原因进行分析。结合铝电解电容物理结构和几种重要参数随工作频率和温度变化的运行特性,从电容内部出发研究了铝电解电容退化失效的模式和原因。并选择等效串联电阻(Equivalent series resistance,ESR)和电容量(Capacitance,C)作为其退化失效的表征参数,然后继续分析研究常用的铝电解电容失效物理模型,为文章后续铝电解电容的性能退化评估提供理论基础。铝电解电容的性能退化将引起系统整体性能的变化,其中直流母线电容波形信号的变化是最为明显且易得的表征。接着通过对直流母线电容纹波电压电流的分析,当系统其他参数不变时,铝电解电容ESR和C的变化对纹波电压和电流有着较大的影响,当纹波电压达到一定的程度时表示铝电解电容失效,并通过实验仿真得到验证。其次,通过铝电解电容的剩余寿命技术研究进行铝电解电容退化状态的定量化分析,然而传统基于理想退化模型的剩余寿命预测因为实际监测过程中的噪声干扰,预测结果有着较大的误差;通过使用NASA研究中心的电解电容C和ESR的退化实验数据,提出一种基于电容量C的经验退化模型,并采用标准粒子滤波算法对剩余寿命进行预测。实验表明该方法预测误差较小,且所得结果可以由概率密度分布(PDF)给出,有着较好的预测效果,该方法同样适用于ESR。最后研究了直流母线铝电解电容退化表征参数C和ESR的在线监测方法,通过对传统基于脉冲电流下ESR的离线监测方法的研究,改进了一种基于放电规律的铝电解电容参数监测方案,通过实验仿真验证该方法取得较好监测效果,C和ESR的监测相对误差在1%左右。但是该方法的使用限制在电源系统的停机阶段,且对于直流母线电容存在并联结构的情况下较难实现,不满足铝电解电容在线监测以及简单操作的要求;进而通过对铝电解电容的损耗功率的研究,设计出一种ESR的在线监测模型,并通过仿真以及在线监测实验验证了方案的有效性,实验相对误差在1%以内,取得良好的监测效果。更多还原

【Abstract】 AC power supply has been widely used in various fields of life and production.In particular,high-power AC power supply is a reliable guarantee for the stable operation of modern military electronic equipment.The reliability of AC power supply is particularly important.As one of the key power components of power electronic systems,aluminum electrolytic capacitors play a role in filtering and storing energy in AC power supplies,balancing the energy difference between multi-level converters,and are an important guarantee for the stability of AC power supplies.However,in all power devices,the failure rate of aluminum electrolytic capacitors is high.The failure of aluminum electrolytic capacitors will inevitably cause safety problems for AC power supplies,and even worse,threaten people’s lives.Therefore,research on the reliability of aluminum electrolytic capacitors in AC power supplies is of great significance for improving the stable operation of AC power supplies.In this paper,the 10 k VA three-phase full-bridge inverter power supply is selected as the research object.Firstly,a simulation model is established to observe the waveform signal of DC-Link aluminum electrolytic capacitor,and the failure reason of the inverter module is analyzed.Combined with the physical structure of aluminum electrolytic capacitor,the operating characteristics of several important parameters with the change of operating frequency and temperature are analyzed.Then,from the inside of the capacitor,the degradation failure modes and reasons of the electrolytic capacitor were studied in essence.The equivalent series resistance ESR and capacitance C were selected as the characterization parameters of the degradation failure,and the influence of the change of ESR and C on the whole power supply system was analyzed.The failure physical model of aluminum electrolytic capacitor is studied to provide a theoretical basis for the subsequent residual life prediction research.The degradation of the aluminum electrolytic capacitor will cause the change of the overall performance of the system,among which the change of the DC-Link capacitor waveform is the most obvious and easy to obtain representation.Then through the analysis of the DC-Link capacitor ripple voltage and current,when other parameters of the system remain unchanged,the changes of the aluminum electrolytic capacitor ESR and C have a great impact on the ripple voltage and current,and when the ripple voltage reaches a certain extent,it indicates the failure of the aluminum electrolytic capacitor,which has been verified by the experimental simulation.Secondly,a quantitative analysis of the degradation state of aluminum electrolytic capacitor is carried out through the research of the residual life technology of aluminum electrolytic capacitor.However,the traditional residual life prediction based on ideal degradation model has a large error due to the noise interference in the actual monitoring process.An empirical degradation model based on capacitance C was proposed by using degradation experimental data of electrolytic capacitor C and ESR at NASA Research Center,and the residual life was predicted by using standard particle filter algorithm.Experimental results show that the prediction error of this method is small,and the results obtained can be given by probability density distribution(PDF),which has a good prediction effect.This method is also suitable for ESR.Finally,the online monitoring method of the degradation characterization parameter C and ESR of DC-Link aluminum electrolytic capacitor was studied.Through the study of the traditional offline monitoring method based on pulsed current ESR,a monitoring scheme of aluminum electrolytic capacitor parameters based on discharge law was improved.The experimental simulation verified that this method achieved good monitoring effect.The relative error of C and ESR monitoring is about 1%.However,the use of this method is limited to the shutdown stage of the power supply system,and it is difficult to realize when the DC-Link capacitor exists in parallel structure,which does not meet the requirements of on-line monitoring and simple operation of the aluminum electrolytic capacitor.Then,through the research on the loss power of aluminum electrolytic capacitor,an ESR online monitoring model is designed,and the effectiveness of the scheme is verified through simulation and online monitoring experiments.The relative error of the experiment is within,and good monitoring effect is achieved.更多还原