Traditional photovoltaic grid connected inverter usually has power frequency transformer or high frequency transformer, which brings many inconvenience. Due to the existence of equivalent parasitic capacitance of photovoltaic cell board to ground, it will lead to the generation of ground drain current in the photovoltaic grid connected inverter system without isolation transformer. In this paper, a new NPC topology of two-stage non-isolation transformer is adopted, the topology can completely eliminate the leakage current, suppress the pulsation of neutral point potential. The former stage adopts single current loop control to realize the maximum power point tracking of photovoltaic cell board; The second stage adopts the DC voltage outer loop and the double closed-loop control of the grid connected current inner loop. The advantages and disadvantages of PI and quasi PR are compared and analyzed. It is pointed out that the quasi PR controller is more suitable for the control of single-phase photovoltaic grid connected inverter. The experimental prototype of 5 kW new type double stage non-isolated transformer NPC grid connected inverter is built. The experiment of the new NPC topology is carried out. The results verify the feasibility and superiority of the new topology.
Research on Photovoltaic Grid Connected Inverter Without Isolation Transformer
Lect. Notes Electrical Eng.
International Conference on Electrical and Information Technologies for Rail Transportation ; 2021 October 21, 2021 - October 23, 2021
Proceedings of the 5th International Conference on Electrical Engineering and Information Technologies for Rail Transportation (EITRT) 2021 ; Kapitel : 16 ; 135-147
2022-02-22
13 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
Optimal sizing of solar array and inverter in grid-connected photovoltaic systems
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