Simulation And Research Of Grid Connected Photovoltaic Generation Based On PSCAD/EMTDC

As the most promising renewable energy,solar energy has huge reserves and no pollution.China has rich solar energies and an immense potential forutilization,providing the precondition for the development of photovoltaic industry and building a diversified energy structure in our country.Photovoltaic grid connected is the hotspot of solar power generation research,including the maximum power tracking control and grid connected control strategy of these two core issues.In this paper,the three-phase photovoltaic grid connected system is taken as the research object,and the simulation model of photovoltaic grid connected system is built by PSCAD/EMTDC to do the research and analysis of photovoltaic grid connected problems.Firstly,this paper introduces the research background and significance of grid-connected PV system;secondly,this paper introduces the model of photovoltaic cell,the type and the topological structure of photovoltaic system,and expounds the related technical principles of photovoltaic grid connected system,and introduces the energy storage device model of photovoltaic power system;then the mechanism and the classification of islanding detection methods are analyzed and summarized,which focus on over/under excitation protection and over/under frequency protection in passive scheme and frequency offset detection in active schemes;based on PSCAD/EMTDC,the simulation model is built and tested,and the short circuit current and open circuit voltage are measured under different illumination intensity and temperature,and the result shows that under the condition of constant temperature,the open circuit voltage and short circuit current increases with the increase of illumination intensity;under the condition of constant light intensity,the open circuit voltage decreases and the short-circuit current increases with the increase of temperature,and this paper completes a MPPT control based on conductance increment method,and finally explores the influence of illumination intensity on the maximum power point;finally,the simulation of grid-connected photovoltaic system is completed,and it mainly includes four parts: the modeling of the solar panel system,the realization of MPPT control based on the constant voltage method,the research on the control strategy of the inverter and the simulation of the grid connected system.In the end,the work of this paper is summarized,and the future research contents are put forward.