Input-parallel output-series isolated DC-DC converter for PV generation system

The topology of photovoltaic (PV) power system is categorized on the basis of number of power processing stages. The single-stage dc-dc converter has the advantage of simple structure and high efficiency, however it must handle all tasks itself, i.e., maximum power point tracking and, perhaps, voltage amplification. Instead, the control system of the dual-stage dc-dc converter is simple but its complex structure affects its efficiency. Also the architecture of the PV power systems also affects the efficiency greatly. So in this paper, a new architecture with an input-parallel-output-series isolated dc-dc converter is proposed. In this architecture, most of the PV power is directly transferred to the DC bus through the dc transformer and the voltage difference between the PV string and the fixed DC bus is compensated by a power compensator. Thus, a high efficiency can be reached. A 1 kW prototype is built and tested in the lab. The experimental results are presented to verify the validation of the effectiveness of the proposed PV architecture.