Adaptive Decoupling Control Of Doubly-fed Wind Power Generation System Based On Inverse Model

As the shortage of traditional energy and environmental pollution worsening, the development and utilization of renewable energy represented by wind energy is taken seriously by many countries. Wind power will become a huge emerging power markets, and variable speed constant frequency (VSCF) doubly-fed wind power system is widely used as mainstream model in the wind power field, due to its superior performance, outstanding advantages. The high-performance control strategy of Doubly-fed wind power generation system is becoming a research hotspot at home and abroad.In the first part of this thesis, the VSCF operation principle of doubly-fed generator operation has been researched. And the principle of maximum wind power tracking has been analysed Combined with wind turbine operating characteristic. Considering there are different operation states and control strategies of doubly-fed wind power system before and after grid connected, based on the idea of separate modeling, time-sharing working, the no-load and power generating simulation models have been established, combined with each other’s control strategies and the enable module, form the whole simulation system of the continuous operation process from no load to grid connected.In this thesis, the inverse system method is applied to the linearization and decoupling of the doubly-fed wind power system which is a nonlinear and strong coupling multivariable system, the model of inverse system when no load, and the inverse system of both power control and speed control scheme during the maximum wind power tracking process when connected to the grid, has been deduced respectively. In view of the pseudo linear system formed after inverse system, introduces a modified internal model control structure, to improve the robust stability and high order no static error tracking performance of the control system. In order to solve the system parameter drift problem, in this thesis a kind of linear equation with parameters to be identified as unknown variables is proposed, and realize online identification of the system parameter by using the recursive least squares method. Combined the parameter online identification module with the inverse system internal model control, implements the adaptive decoupling control of the doubly-fed wind power generation system.The simulation results proves that the whole simulation system has successfully completed the continuous control simulation; Internal model control strategy based on inverse system has completed the maximum wind power tracking control very well, and realized the precise decoupling control of the active and reactive power、reactive power and rotate speed; Correctness of the online identification is validated by computer simulation, and the online identification has improved adaptive ability to parameter time-variance of the control strategy.