Topology of the Energy Harvesting System for Large-Scale Solar Power Plants Using a Two-Stage Differential Power Converter

The capacity of photovoltaic installations continues to grow and reaches hundreds of megawatts. Large-scale PV systems are valued for their high efficiency when their architecture is renewable and reliable. In addition, energy conversion costs are low and the installation is able to mitigate the effects of partial shading. Plants with distributed power electronics converters have demonstrated higher energy output, better reliability, significantly reduced design costs, and greater flexibility in PV plant designs. The article analyzes energy harvesting architectures for large-scale solar power plants. Advantages and disadvantages of using a boost converter in these architectures are considered. The topology of a two-stage differential power converter with DC collection network characteristics is presented, which provides higher energy output for large-scale solar power plants. The principle of operation of the converter and the flow of current in the circuit during switching are presented. The approach is to divide the solar panels into several zones using a central grounding point with a DC collection network and connecting them using a fractional-rated current-voltage balancing converter topology to achieve maximum power point tracking, thus mitigating the effects of partial shading and temperature drop. The proposed topology is characterized by fractional power, higher efficiency, scalability and lower cost. The operation of current balancing and voltage equalization cascades, which process partial power and allow groups of photovoltaic panels to work at maximum power under the influence of environmental conditions, has been calculated. It is shown that the proposed system can be scaled for large-scale solar power plants, while creating homogeneous and heterogeneous photovoltaic installations using photovoltaic panels from different manufacturers.