Doubly-fed Wind Turbine Power Control Strategy Research

In recent years, with resource depletion and environment pollution problem, new energy technology research received wide attention worldwide.As a kind of high efficient, clean new energy among them, reasonable development and utilization of wind power and the study of wind power technology have important significance.At home and abroad, the variable speed constant frequency doubly-fed induction generator (DFIG) are mainstream models of wind farm. With the increasing capacity of wind turbine, reasonable power control strategy and maximizing the use of wind power have become important parts of the study of wind power generation technology. The main works accomplished in this paper are:1. The mathematical model of doubly-fed wind power generators is established. The basic structure and working principle of doubly-fed induction generator (DFIG) was introduced at first and the three-phase static a-b-c system mathematical model is established to settle the basis of analying the running characteristics and method research control.2. The power decoupling strategy based on vector control technology is established. After adopting the main control strategy of DFIG, the vector control technology, the paper simplify the mathematical model, to make it into a two phase rotating d-q coordinate system based on the idea of coordinate transformation of doubly-fed motor three-phase static a-b-c coordinate system; The control strategy of the stator flux rotor side of the power converter and grid voltage oriented vector control strategy under the network side the vector control strategy of the power converter is deduced to realize the active and reactive power decoupling. Electromagnetic transient model of doubly-fed wind power generator is realized by using PSCAD/EMTDC software. At last active and reactive power is realized by using the software of independent regulation, namely power decoupling is realized.3. Using power control strategy of indirect speed control mode, optimal speed control is achieved through the control of DFIG electromagnetic resistance torque to accomplishing the maximum wind energy capture. The basic characteristic of DFIG and the operation area is introduced, and on this basis, discussing the doubly-fed wind power generation system of maximum wind power tracking process and the calculation process of the reference power. Maximum wind power tracking is realized by using PSCAD/EMTDC software, verifying and improving the proposed active and reactive power coordinated control strategyAll in all, the research set the electromagnetic transient model of doubly-fed wind power generator and realize the independent regulation of active and reactive power based on PSCAD/EMTDC software. Then the maximum wind power tracking is realized, and the strategy of active and reactive power coordinated control is verified and improved. The research in this paper could provide experiences and references for the research of doubly-fed fan power control research.