Control System Design Fora Doubly-Fed Wind Turbine

The purpose of this paper is using MATLAB and it’s SISO control tool to design a doubly-fed wind turbine(WT) control algorithm which will control the WT and get the most wind energy to provide the WT economic benefits. At the same time, using the RTW tool to get the product of the controller form the design, that is rapid control prototyping(RCP). The design of wind turbine control algorithm had a well stability and dynamic, meanwhile, it will effectively reduce the fatigue load of the WT. At the last, using MATLAB and Bladed software to simuliation and testing the designed controller.Rotor is the WT device which captures wind. For a designed rotor, it has it’s own operating characteristics. In order to achieve maximum power, rotor below the rated wind speed must be running at the maximum tip speed ratio. Because the random of the wind, how to control the generator speed make it followes the wind speed is the first question in this paper.Taking into account the mechanical and the electrical limits, it’s output power can not be unlimited at above rated wind speed, how to control the WT to output a stable power is the second question. The third issue would be considered is how to design the damper to reduce torsional vibration of the WT.Doubly-fed wind turbine has part of the power converter, so when the grid voltage drops it will cause a rapid increase, shock even stop. In this paper a designed controller is discussed to solve those problems. As we know WT is a fairly large and complex system, it has a lot of very detailed technical questions, such as coordination problems of torque control and pitch control, filter etc. They are also to discuss in this paper.Firstly, this paper introduces the double-fed WT components, and the operating principle. Second, analyzes the characteristics of the WT, and designs a control algorithm. That is, control the generator torque to achieve the maximum power curve at the low wind speed, pitch control strategy had been use above rated wind speed to make the power stably. Third, discuss the problem of switching the two controllers. Fourthly, using the Bladed software modeling doubly-fed wind turbine, analysis of the WT mechanical frequency characteristics, to avoid the resonance and design filter. Once again, export the model as MATLAB transform function, then use the MATLAB software tools to design the controller. Fively, the designed control algorithm had been put into the Bladed software to simulation and test. Finally, design a Hardware In Loop (HIL) test platform to test the controller using PLC and Bladed by the MATLAB RTW.