Study On Conversion Efficiency Of Inverter In The Photovoltaic System

With the vigorous development of the global solar and other new energy sources,solar power technology requirements are also rising.And the PV inverter as core component of the photovoltaic power generation,which means higher demands efficiency and performance for it.But our country’s photovoltaic inverter technology level is relatively backward,how to improve the efficiency and performance of the PV inverter in the current technical conditions is a research hotspot.This paper involve Sichuan Science and Technology Support Program— "photovoltaic inverter power generation systems and key components of photovoltaic cells technology" research project sub-topics,for the large PV inverter efficiency issues,using digital simulation methods and semi-physical simulation,completed the following work:(1)According to the output characteristics of solar cells,analysis of the MPPT theories about the CVT,the P&O and the IncCond,An improved P&O is proposed,which the IncCond as a relaxation factor.(2)In terms of the adaptive variable step algorithm for the proposed,establishment of a digital model of the MATLAB software,And through traditional variable step algorithm and improved algorithm results verify the validity of the algorithm.(3)Establishment of experimental models of photovoltaic semi-physical simulation through RTDS simulation system,directed against two algorithms for the simulation results finished semi-physical simulation verify the accuracy of the simulation results and verify usefulness of the improved algorithm.(4)Analysis of the two-level,E-shaped and T-shaped three-level three-phase inverter topology,state losses calculation method and switching losses calculation method about the three topologies inverter is derived.(5)Directed against three kinds of inverter topologies for the establishment of a semi-physical simulation model,compared of the three structures inverter power loss and temperature changes by experiment,determined the T-shaped three-level inverter has lower power consumption and temperature requirements.(6)In the proposed improved algorithm and T-shaped three-level inverter based,established of a photovoltaic power generation system experimental platform.According to the needs of the experimental platform,to the DC link capacitors,filters,radiators and the laminated busbar selection design and tuning parameters,and through the entire photovoltaic system and power generation experiments to verify its legitimacy.