Study on the effectiveness of commercial anti‐islanding algorithms in the prospect of mass penetration of PVs in low‐voltage distribution networks

In the coming years, distribution grids will be progressively flooded by renewable energy sources (RES) that will be interconnected with the main grid through power electronic converters. Photovoltaics (PVs) are one of the most promising renewable technologies even for densely built-up areas where space problems are inevitable. The high penetration prospect of PV facilities on low-voltage distribution networks raises questions regarding the necessity of advanced functions that will enable electronically coupled RES to support the operation of distribution grids and to enhance their reliability. In this context, the objective of this study is to investigate the effectiveness of various islanding prevention measures installed in commercial PV inverters, when multiple inverters are operating in parallel with a low-voltage distribution network (LVDN). Extensive experiments were performed under various PV penetration levels, linear/non-linear load and over/under voltage and over/under frequency conditions, as well as for various values of total harmonic distortion of the mains voltage. Further to the primary statistical analysis, the results were analysed in depth by advanced mathematical methods such as box plot and cluster analysis. The findings of this study indicate that commercial anti-islanding techniques present a high probability of failure in the case of multiple PV units at the same point of common coupling, calling for new and more advanced algorithms.European Commission, H2020, 65411

Experimental study of a low-voltage PV cell-level DC/AC converter

Summarization: This paper focuses on the design of a low-voltage power converter for an on-chip PV cell-level inverter. Various topologies are discussed for the DC/DC stage, whereas the ZVS quasi-resonant boost and the synchronous boost are considered the most appropriate for this application. Both the aforementioned topologies are modeled and evaluated in terms of efficiency, by the aid of PSpice simulations. Due to requirements and limitations of the available 0.18 μm CMOS process technology, the synchronous boost is finally chosen as the most appropriate solution. As for the DC/AC stage, the H-bridge inverter configuration is selected, as a simple, compact and cost-effective solution. A prototype converter is designed and constructed with discrete components, so as to validate the functionality and performance of the proposed system. Finally, experimental results are presented, indicating the high efficiency that can be achieved.Παρουσιάστηκε στο: 2021 10th International Conference on Modern Circuits and Systems Technologie

Analysis, design and simulation of an on-chip DC/DC/AC conversion system for PV applications

Summarization: This paper presents the analysis and design procedure of a low voltage, reconfigurable, on-chip DC/DC - DC/AC power conversion system for PV applications. The whole work is carried out in the context of a novel smart PV system development, which is based on integrated PV cell inverters. Various power converter topologies are investigated in order the most appropriate for the DC/DC and DC/AC power stages to be selected. The synchronous boost DC/DC converter and the H-bridge inverter are the preferred solution, in terms of complexity, efficiency and cost. The specifications of the power conversion system are given, along with the theoretical analysis for the synchronous boost converter and H-bridge inverter operation. Moreover, the chip design process is presented, highlighting the design constraints and limitations obtained. Finally, in order the functionality of the above concept to be validated, PSpice simulations are carried out, indicating the high efficiency and low complexity of the proposed power conversion system.Παρουσιάστηκε στο: 5th Panhellenic Conference on Electronics and Telecommunication