A Reconfigurable Modular Topology for PV Converter to Improve Overcurrent Capacity and Flexibility

The existing topologies of PV generation units have fixed overcurrent capacity for each conversion stage, making it difficult to respond to various disturbances on PV and grid sides. This paper proposes a family of reconfigurable modular PV converter with flexible modules switching between the PV, grid, and energy storage (ES) sides via flexible switches which are composed of thyristors. We further study an optimal topology configuration for the non-ES case. Its control system and adaptive flexible modules dispatch strategy for efficient co-operation between PV and grid are proposed to maximize the utilization of hardware resources under various conditions such as variation of irradiance and low-voltage ride-through (LVRT). The proposed topology and its control strategy bring out enhanced flexibility and overcurrent capacity at limited additional hardware cost. The advantages of the reconfigurable modular PV converter are verified by simulation in MATLAB/Simulink and experimental tests of prototype. Experimental results demonstrate that the proposed system can achieve twice overcurrent capacity via topology reconfiguration in less than 1.85 milliseconds.