A cascaded-boost topology for electrolyte-less power conditioning system suitable for PV residential applications

Single-phase inverters need large bulk DC link electrolyte capacitors which reduce the life time of the converter circuit. Furthermore, there is a safety need for low input voltage in photovoltaic (PV) residential applications. A new cascaded power-decoupling topology is proposed in this paper with film capacitors and high step-up ratio. The topology is based on cascaded double boost; the output of the source side boost (the auxiliary DC link) is free to oscillate in double frequency of the AC output around a controlled average voltage. Besides, the second boost controls the main DC-link voltage within a demanded ripple range. A detailed design procedure of the topology is proposed, followed by transient analysis and controller design. Finally, the proposed circuit will be verified by simulation and experimental results.