Expandable Input Impedance Sourced Isolated Resonant Converter Operated With PSO for PSCs

Low-voltage renewable sources often require efficient high-gain power converters to boost the voltage to existing voltage levels while ensuring its safety through isolation. These converters often use a bulky electrolytic capacitor (EC) that suffers from aging effects, leading to an unreliable operation. Moreover, harnessing the global peak power from solar panels is another challenge due to multi-peak PV characteristics formed under partial shading conditions (PSCs). Thus, to address these concerns, this paper proposes an electrolytic capacitor-less expandable input impedance sourced isolated resonant converter (EIISIRC) and integrates it with solar PV using a particle swarm optimization (PSO)-based algorithm to verify its feasibility. The proposed converter is an expandable input impedance sourced resonant converter where the input impedance network is expandable to boost the voltage level with n cells. Moreover, the resonant converter is analyzed and designed to operate with zero voltage switching using the first harmonics approximation (FHA) technique. The proposed converter utilizes small-sized, reliable film capacitors for voltage smoothening and to improve the lifespan of the converter. Additionally, the film capacitors' compactness and longer lifespan are compared to those of traditional ECs. Furthermore, a PSO-based MPPT algorithm is applied to harness the solar power at global maxima under PSCs. A 500 W scaled-down laboratory prototype is developed to evaluate the performance of EIISIRC for n = 3 using a Chroma's PV emulator (62100H-600S) under constant irradiance and PSCs.