Studies On Grid-connected Photovoltaic Inverter System Basing On DSP Control

With the high-speed development of society, technology and population of human civilization, the human energy consumption is increasing fastly.According to the prediction of the professionals, the fossil energy such as oil and coal will be depleted in one hundred years.So if new forms of energy cann’t be developed in time, we human will be faced with energy crisis.Besides, with the use of fossil fuels, the environment problem is becoming more and more seriously, which ultimately inevitable affects the survival of the humanity.Therefore, the issue of the energy and environment should be taken very seriously.In order to solve this serious issue,we must look for new renewable energy.The inexhaustible solar energy is just the proper clean energy human need.And the recent Fukushima nuclear crisis and the increasing of oil price especially take new chance to this new energy. Photovoltaic technology is the major form of using solar energy, and the grid-connected photovoltaic inverter system which connects the photovoltaic cell arrays and the grid is the key of this technology.The main function of the grid-connected photovoltaic inverter system is inverting the DC generated by the cell arrays to AC which fits the need of the grid to achieve the grid-connection.The exploration of this technology is of great theoretical and practical significance.This paper will analysis and model the photovoltaic cell arrays and each involved parts of the photovoltaic system basing on PSIM9.0,and the maximum power point tracking of photovoltaic cells and the switching variable controling method of three-phase inverter are two key points which will be particularly simulated and discussed in this article.The whole design method should fit the need of dynamic and static stability of the system.Besides,the proper LC filter should be selected in order to modulate the total harmonic distortion(THD) of the grid-connected current.