Inductive-boost switched-capacitor DC/DC converter for maximum power point tracking photovoltaic systems

With the advent of the photovoltaic (PV) energy source that has a variable and low dc output voltage, a high step-up dc/dc converter is necessary for grid-connected power conditioning systems. These power conversion systems are required to comply with strict technical and regulatory criteria to ensure a safe, reliable and efficient operation of the overall system. In this regard, this paper proposes an isolated and non-isolated high gain switched capacitor dc/dc conversion system. This converter can offer high efficiency with the possibility of the adjustable impedance matching for PV systems. It can also achieve the high voltage gain without requiring high values of duty cycles. Soft-switching techniques are adopted to achieve minimal switching losses and maximum system efficiency. The presented approach can be applied to switched capacitor converters with any number of modules to improve the functionality of the closed loop control system. Furthermore, a capacitor soft charging function has been taken into account to suppress an inrush current at the start of the operation, as well as to avoid an extra voltage and current stress for power electronic components.