A Symmetrical Architecture for PV String Using LLC-based Voltage Multiplier by Differential Power Processing Technique

To resolve the mismatching issues in photovoltaic (PV), different differential power processing (DPP) architectures have been presented. A novel DPP architecture is presented in this paper with a simple circuit and open-loop control. The proposed DPP converter shows symmetry and flexibility by utilizing the Cochvroft & Walton Circuit, where the PV string can be connected per side of the voltage multiplier (MV). The LLC inverter requires no feedback loop, which simplifies the circuit. Experimental results for the PV module with four submodules show that overall PV module output power and efficiency are both improved significantly under shading conditions. Furthermore, this proposed DPP converter has great advantages in cost-saving, especially in extended-long PV string.