基于非反相升降压变换器的组串级电弧故障检测能力研究

Module-level power electronics can optimize power generation for each photovoltaic (PV) panel. However, it increases the possibility of DC series arc fault between the PV panel and DC-DC converter. The damaged and loose connector can induce arc faults. Previously, frequency domain analysis using PV current, such as Fourier transform and wavelet transform, was widely employed for series arc fault detection. However, fault detection with signal processing is not consistent with system configurations. In this paper, the characteristics of arc resistance are investigated to detect and extinguish arc faults using the power modulation and signal processing. A non-inverting buck-boost (NIBB) converter is analyzed according to control freedom to implement power modulation. A duty modulation strategy for the non-inverting buck-boost converter is designed for series arc fault detection and extinguishing with considerations of arc and PV characteristics. A hybrid algorithm using time domain analysis is proposed, which can classify normal and arc fault conditions. It can maximize power generation under normal conditions. Experimental results using an 800-W prototype verify the performance of proposed modulation algorithm.