Simulation Of MPPT And Grid-connected Inverters For Offshore Wind Farms

With the shortage of fossil energy and the increase of environmental pollution,wind power has received attention from many countries all over the world in recent years.Because of the abundant resources of offshore wind energy,research for high-power offshore wind power generation and its grid-connected technology are an important direction of renewable energy research.At present,the main wind turbine used in offshore wind power farm was high-power permanent magnet direct-drive wind turbines,and electric energy needs to be connected to land by submarine cables.In this case,three main research works have been done:Firstly,the currently used 2.5MW wind turbine was designed and modeled.According to the structure of 2.5MW permanent magnet direct-drive wind turbine,the topology of the main circuit of direct-drive permanent magnet synchronous wind power generation system was given out.Moreover,this research completed the MATLAB modeling of high-power wind turbine and permanent magnet synchronous generator.Then,a distributed control scheme was designed.In this method the wind turbine is rectified and boosted into the DC bus,transported by the submarine cable to the land,and finally connected to the grid through inverter and boost.The modules of Grid-connected inverter such as boost chopper circuit and SVPWM three-level inverter were simulated in MATLAB.On the basis of analyzing the maximum power tracking control method of the existing wind turbine,the traditional hill climbing algorithm was improved.The variable step climbing algorithm was used to control the maximum power of the wind turbine and improve the tracking efficiency.Maximum power tracking and grid-connected inverter part of the high-power wind turbine can be simulated and analyzed by the software of MATLAB/SIMULINK.Comparing the effect of adding maximum power tracking and not adding time.And comparing output power and grid-connected voltage waveforms at different wind speed was compared.The simulation results showed that the system could meet the requirements of smooth operation and grid-connected operation of high-power fans.