Studies of large‐scale DC connected photovoltaic power system based on multi‐modular cascaded DC‐DC converter

DC collection and transmission is one of the major development directions large-scale photovoltaic (PV) power system. In order to achieve low-cost, high-efficiency long-distance PV power, this paper adopted a grid-connected topology by using multi-modular cascaded DC-DC converters, forming an input-independent output-series (IIOS) system, LLC type converter based on IGCT magnetically integrated transformer was proposed in paper, which can significantly increase capacity, efficiency density converter. And equalization unit half-bridge for case uneven irradiation inputs. addition, control method Nearest Level Modulation (NLM), greatly simplifies design acquisition Furthermore, parametric 50MW system presented, simulation carried out verify feasibility advantages paper. The IIOS more suitable high-capacity, transmission, serve as reference systems.