Doubly-fed Wind Turbine Power Decoupling Control Strategy

Wind energy as a clean renewable energy has a considerable developmentprospects at the contemporary of the great growing of resource consumption,while the equipment of wind turbine which use the doubly-fed generator has ansignificant advantages and broad prospects. The technology of the variablespeed and constant frequency doubly-fed wind generator narrow the capacity ofinverter that connect the rotor side in parallel way and use the technology offield oriented in the side of the stator. By controlling the excitation current thepower decoupling of doubly fed induction generator will achieve.Firstly, the article elaborated the research status of the technology of windpower and the variable speed and constant frequency doubly-fed wind generatorbetween domestic and abroad and explain all kinds of control strategy aboutwind turbine and the trend of the development. Based on the theory of vectorcontrol, the article analysis the mathematical model of doubly-fed generatorunder the three-phase stationary coordinate system, the mathematical modelunder the two-phase stationary coordinate system and the mathematical modelunder any rotating coordinate system in two-phase. Utilizing the control strategyof stator flux oriented vector control combined with the theory about the controlsystem of double-loop, we will construct the control system of doubly-fed windturbine power decoupling.Secondly, field oriented plays an importance role in the control technologyof doubly-fed wind turbine power decoupling. The article comply the statormagnetic field orientation by utilizing the improved stator flux observer. Focuson the disadvantage that the parameter of traditional PI regulator is difficult toset and dynamic performance is poor, the power decoupling control systemadjusted the active power and reactive power independently by applying thefuzzy PI regulator.Finally, based on the basis of the above theoretical analysis the articledesign the doubly-fed induction generator power decoupling control system preliminary and execute the system simulation under the condition of gradientwind. The research results of MATLAB proved that the control system hasachieve the target of power decoupling control which has a small overshoot andthe dynamic performance has been improved.