1 The Faculty of Engineering and Science, Aalborg University, VBN2 Power Electronic Systems, The Faculty of Engineering and Science, Aalborg University, VBN3 Department of Energy Technology, The Faculty of Engineering and Science, Aalborg University, VBN4 Technical University of Crete5 Technical University of Crete
The transformerless dc/ac inverters are critical components in the rapidly growing market of grid-connected photovoltaic (PV) applications. They are synthesized by combining available solutions in terms of the power-section topology, power-semiconductors manufacturing technology, and structure of the output filter. In addition, the silicon carbide (SiC)-based power semiconductors are capable to operate reliably at high operating temperature and switching frequency levels combined with a very high efficiency. In this paper, a new design technique is presented for optimizing the switching frequency and structure of the output filter (either LCL- or LLCL-type) in transformerless H5 and conergy-neutral point clamped (Conergy-NPC) PV inverters, which employ SiC-type power devices. The design results demonstrate that the optimized SiC-based H5 and Conergy-NPC transformerless PV inverters are more effective in terms of energy production than their nonoptimized and silicon (Si)-based counterparts. In addition, by reducing the market price of SiC-type power semiconductors to the level of Si-based power devices, enables the development of optimized SiC-based PV inverters with a lower cost of energy than the corresponding PV inverters based on Si technology, thus maximizing the economic profitability of the PV system.
I E E E Journal of Emerging and Selected Topics in Power Electronics, 2015, Vol 3, Issue 2, p. 555-567