Due to the environmental concerns and new energy policies, worldwide expectations for energy production utilizing photovoltaic (PV) systems are increasing significantly. The aluminum electrolytic capacitor (AEC) is extensively used in filtering application for power electronic converters in PV systems since they can achieve the highest energy density with the lowest cost. However, the lifetime of an AEC is limited due to the electrolyte vaporization. The degradation of AECs challenges the efficiency and reliability of a PV system. Therefore, the health-monitoring of AECs is indispensable for the PV systems to operate reliably. In this paper, an online AEC-monitoring scheme based on magnetic-field sensing is proposed for PV systems under various working conditions. The AEC-monitoring technique using the equivalent series resistance (ESR) and capacitance (C) as the health indicators were developed for the power electronic converters in PV systems. The proposed methodology considering the voltage drops on C can improve the accuracy in ESR-estimation and achieve the estimation of C. The simulation results with Simulink verified that the proposed method was capable of estimating the health indicators accurately over various levels of solar irradiance and ambient temperature. The tunneling magnetoresistive (TMR) sensors were pre-calibrated from −25 to 100° C for implementation in PV systems. The experimental results proved that TMR sensors could measure the current of AECs effectively to achieve the precise estimations of the health indicators using the proposed technique. This technique is non-invasive, compact, and cost-effective since it can be realized with the TMR sensors or other MR sensors.

中文翻译：

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磁阻传感器在线监测光伏系统铝电解电容器

由于环境问题和新能源政策，全世界对利用光伏 (PV) 系统进行能源生产的期望正在显着增加。铝电解电容器 (AEC) 广泛用于光伏系统中电力电子转换器的滤波应用，因为它们可以以最低的成本实现最高的能量密度。然而，由于电解液蒸发，AEC 的寿命受到限制。AEC 的退化对光伏系统的效率和可靠性提出了挑战。因此，AEC 的健康监测对于光伏系统的可靠运行是必不可少的。在本文中，提出了一种基于磁场传感的在线 AEC 监测方案，适用于各种工作条件下的光伏系统。使用等效串联电阻 (ESR) 和电容 (C) 作为健康指标的 AEC 监控技术是为光伏系统中的电力电子转换器开发的。所提出的考虑 C 上电压降的方法可以提高 ESR 估计的准确性并实现 C 的估计。 Simulink 的仿真结果验证了所提出的方法能够准确估计各种水平的太阳辐照度和环境的健康指标温度。隧道磁阻 (TMR) 传感器在 -25 至 100° C 范围内进行了预校准，以便在 PV 系统中实施。实验结果证明，TMR 传感器可以有效地测量 AEC 的电流，从而使用所提出的技术实现对健康指标的精确估计。这种技术是非侵入性的、紧凑的、