An active clamped L-L type ZVS current-fed front-end DC-DC converter based solid state transformer in grid connected mode PV applications

This paper utilised a solid-state transformer (SST) with an active clamped L-L type current fed front-end converter for maximum power extraction (MPE) and voltage boost operation. The proposed system employed perturb and observe (P&O) based MPE and upheld the ZVS operation of all primary side switches and ZCS operation of all secondary side rectifier diodes for various insolation conditions. The proposed system developed a new fundamental extractor titled multi-level cascaded dual double fundamental signal extractor (MCDDFSE) and is utilized in the control algorithm for synchronization with the utility grid. The main objective of the proposed system was to deliver a compact size, reduced weight and cheaper magnetic components-based front-end converter of SST on the photovoltaic (PV) array side and a fast, secure and trustworthy mitigation technique for the grid current harmonics on the utility grid side. The proposed system was trialled on the platform of OPAL-RT (RT-LABv2021.3.2.307) for various grid abnormalities and its behaviour was found well within the IEEE 519 standards. The presented work utilized a solid-state transformer with an active clamped L-L type current fed front-end converter for maximum power extraction from PV arrays by providing ZVS operation to primary side switches and ZCS operation to secondary side rectifier diodes. Further, the generated power is supplied to non-linear load and utility grid at unity power factor and improved power quality by applying a new fundamental extractor topology titled multi-level cascaded dual double fundamental signal extractor (MCDDFSE) based grid control technique. Finally, the proposed system was trialled on the platform of OPAL-RT (RT-LABv2021.3.2.307) for various grid abnormalities and its behaviour was found well within the IEEE 519 standards.image