The Study On Control Strategy Of Double Fed Wind Induction Generator Under The Condition Of Unbalanced Power Grid Voltage

Double fed wind induction generator, it is similar to wound rotor asynchronous induction motor, it has many advantages such as wide speed range, small power device, and the easy control. These advantages make it has a wide application, for example in tidal power, wind power generation. As in recent years, with large-scale construction of wind farm, The technical index of grid-connected wind farms is more and more stringent, The study of wind power generation system. The ever study of wind power generation system is under the ideal power grid voltage condition, and now it is become under the condition of power grid failure. This paper is dedicated to the study of double-fed induction wind generator under the condition of three-phase power grid voltage unbalanced.Doubly-fed induction motor is the generator of the power generation systems. Paper first introduces the operation principle of the double-fed induction wind power system Introduced vector coordinate of transformation theory. Then make the mathematical model of doubly-fed generator work under the static three-phase coordinate transformed to two rotating coordinate system. Then under the condition of power grid voltage unbalance to make the mathematic model of the converter, include mathematic model of grid side converter and the rotor current transformer. The grid side include stator flux oriented and the stator voltage orient. The main content including analysis the network voltage unbalance theory, establish the mathematical model of doubly-fed generator under the condition of network voltage unbalance situation, the mathematical model of network side converter, to put forward different control objectives to network side and rotor side converter. With the different control aims put forward new control algorithm.As for the front theory verification, In parts of the simulation experiments use MATLAB software platform to simulate the wind driven generator. The power of a single wind power generator of 1.5 MW, there has 6 wind power generators, the total power is 9MW.The first process is use the vector control strategy to wind power generators under the situation of balance power grid voltage. Verify the vector control has good control performance under the situation of balance power grid voltage. And then analysis vector control strategy under the situation of unbalance power grid voltage. At last propose the new control strategy under condition of the power grid voltageunbalanced. And to verify the correctness of new control theory under condition of the power grid voltage unbalanced.