Research On Control Strategy For Optimal Power Tracking Of Permanent Magnet Synchronous Generator Wind Turbine

With the vigorous development of wind power industry, people put forward higherrequirements for wind power system security, reliability, cost, power generation efficiencyand power quality, etc. The advanced control technology plays such an irreplaceable rolein satisfing requirements for wind power systems that control strategies guaranteeingstable operations and optimal power tracking of wind turbine gradually become importantand hot research points in the field of control and engineering. Meanwhile, considering therealization in the practical engineering and adjustable control parameters in the controlsystem, and thus from the perspective of the control engineering, the design methodswhich design a simple and feasible control system taking full advantage of the structuralcharacteristics of the system, make the system energy function reflecting the informationof system internal structure and dynamic characteristics, and make the adjustableparameters have a clear physical meaning, have become new and challenging researcharea which needs further reseach in the wind power systems.Control strategies of permanent magnet synchronous wind power generation system,which are based on system physical and structural characteristics, are the research subjectsof this paper. The passivity-based control (PBC) method based on port controlledHamilton model (PCH), speed sensorless control problem and the chaos problem in thewind power system are studied in detail.Main research contents and results include:Firstly, the passivity-based control (PBC) based on port-controlled Hamiltonianmodel for permanent magnet wind turbine system is studied. In the design process of thecontrol system, the PCH model is established by taking full advantage of the physicsstructure of wind turbine system. Then, based on this model, the system is compensated tobe a passive system by redistributing energy and injecting nonlinear damping, to realizethe system stability. This controll method reduces the amount of controller because itdoesn’t need to compensate of part which don’t influence the stability of the system, andmakes the adjustable parameters of the controller have clear physical meaning. In addition,the adaptive control is investigated with the uncertain parameters and the external disturbance.Secondly, the speed sensorless control is researched for the permanent magnetsynchronous generator wind power system based on Hamiltonian model. Using generalaffine nonlinear structure of the Hamilton equation, the mature linear state observer designmethod can be used to design the Hamilton system observer, and a full-order observer isdesigned for wind turbine system based on this idea, which realize the speed sensorlesscontrol. The designed controller is adaptive to the parameter uncertainties and externaldisturbance. And the proposed controller is proved valid by the simulation illustration.Then, the chaos control for the permanent magnet synchronous generator windturbine system based on Hamiltonian model is investigated. Firstly, applying a timescaling transformation and a linear affine transformation, the permanent magnetsynchronous generators wind turbine system is transformed into a model which is similarto Lorenz chaotic model and is demonstrated that chaos phenomena exists when itsparameters are in a certain range of values by simulation. Then, the Hamilton model forchaotic system is built and theH controller is designed to solve problems of chaosandexternal disturbance.Finally, the constant power control strategy in above the rated wind speed is analyseddue to the mechanical load and the electric load limit in the paper research. Consideringthe nonlinear of the wind turbine and parameter variety produced by environmentdisturbance under the big wind speed, the power and part of the system parameters aredisposed as unknown. The adaptive controller is designed to solve the unknown problemsfor wind power system, and the constant power control is realized. Meanwhile,ADRC(active disturbance rejection control) method is proposed for chaos control andeffectively deals with the problems of chaos and disturbancev of the wind power systemand provides theoretical support for engineering realization.