ISOP Multimode Flyback Based Auxiliary Power Module with Ultra-wide Input Voltage Range

In large-scale solar farms, an auxiliary power module (APM) is necessary to convert power from a high-voltage photovoltaic (PV) array to low-voltage loads. The PV array typically operates at a high voltage rating and has an ultra-wide voltage range, presenting significant challenges in designing an optimal APM configuration. To address this issue, this paper proposes an input-series-output-parallel (ISOP) configuration based flyback APM, which can effectively reduce the primary voltage stress and the secondary conduction loss. The system also employs multimode operation to optimize performance across a wide load range. A 300W prototype has been designed, built and tested, which converts an input voltage range of 100-1700V to a 24V output. Experimental results demonstrate a peak efficiency of 95.56% and excellent performance across wide input and load ranges.