The Study On Power Output Characteristics Of Variable Speed Constant Frequency Wind Turbine

In the energy shortage and growing environmental pollution,as a renewable energy development and utilization of wind energy is of great significance.With increasing capacity of the wind turbine,to improve the operating efficiency of unit and maximize to use the wind energy has become an important study part of wind power generation technology.Because of the randomness and uncertainty of the wind,output power of wind farm is unstable and it will disturb the grid.The run characteristic and especially dynamic response of wind turbine is very import in high wind power penetration grid.For the purpose of increasing wind energy utilization and stability of output power,the paper adopts direct torque control technology(DTC) on double-fed wind power generators.Different from the vector control,DTC has a high robustness dynamic torque fast response and simple control structure.It is largely solved complex structure of vector control,great computing capacity and sensitive to changes of parameters.It is a high-performance AC motor control method.The paper first has processed theoretical analysis for double-fed wind generators and wind turbine,given the mathematical model of wind turbine,researched working principle and characteristics of double-fed wind generators,analysed the energy flow relationship in double-fed wind generators,and given the steady-state equivalent circuit of the double-fed wind generators.By coordinate transformation,obtain double-fed wind turbine math model under the rotor coordinate system.Secondly,study DTC basic principles of the double-fed wind turbine based on rotor flux direction,the effect that the rotor voltage vector is for the rotor flux and torque.And set up the simulink models for wind resource,wind turbine, mechanism drive part,double-fed wind generators,pitch control part and no-speed sensor direct torque control system.Construct the complete variable speed constant frequency (VSCF) wind turbine simulink platform. In the study of simulation,analyze the stable characteristic and dynamic characteristic for VSCF wind turbine.The simulink results shows the power output of VSCF wind turbine has certain anti-interference ability and adaptation ablity,and the system performance is stable.Validate the correctness of simulink model and effectiveness of control part design.