Simulation Of Wind Power Converter And Its Port Characteristics

Coal,oil,natural gas and other traditional energy,because of its high energy density and other advantages,is the main force of today's energy market.However,it also brings energy depletion and environmental pollution problems.So,people gradually turn their attention to new energy.Wind energy has been widely studied and applied because of its low cost,environment-friendly and other advantages.The wind drives the generator through the wind turbine to produce three-phase alternating current.However,because the wind speed is constantly changing,the frequency of three-phase alternating current is also constantly changing,which can not be used directly,so it is necessary to convert AC / DC / AC through back-to-back converter.The research content of this paper is the simulation of back-to-back converter.Wind power converter is mainly composed of three parts,three-phase AC variable frequency voltage source,back-to-back converter and power grid.We use electric platform to simulate the working condition of wind turbine.By studying the relationship between wind speed and wind turbine speed,we design the computer program to control the operation of the electric towing platform and realize the simulation of maximum power point tracking of wind turbine.There are two methods of wind turbine simulation.One is to directly use three variable frequency AC voltage sources.The three-phase alternating current generated by this method is lack of high-order harmonic and noise,which is not in line with the actual status of the wind turbine;the other's structure is the same as the electric platform,but the inverter is used at the driving end,so the control algorithm needs to be designed to achieve the maximum power point tracking of the wind turbine.In my method,the motor is directly controlled by a frequency converter by finding the relationship between the wind speed and the rotating speed,and the control accuracy is high.The research of port characteristics is embodied in the design of grid connected inverter parameters.In the first half of the second chapter,the traditional method is used to design the rectifier parameters,from the inner ring to the outer ring,based on the stability setting parameters.And the simulation in Simulink is carried out in the z-domain of the discrete domain,while the parameters are obtained in the s-domain of the continuous domain.So,it needs to be corrected,and the whole process is extremely complex.Therefore,the analysis method based on passivity is used in the design of grid connected inverter parameters.Based on the analysis method of passivity,the original system is transformed into source,output impedance / admittance and load impedance / admittance by using Thevenin's equivalent theorem or Norton's equivalent theorem.The stability of the system can be judged by analyzing the passivity of the impedance / admittance port.Because passivity is the sufficient condition of stability,there is no need to modify the parameters in the simulation,which greatly simplifies the design process.