Research On High-Voltage Ride Through Method For Cage-Rotor Brushless Doubly-Fed Induction Generator Based On Modified Flux Linkage Tracking

Due to the environmental issues and shortage of the non-renewable energy,the wind power generation has attracted the attention of scholars all over the world as a result of its cleaning,energy-saving and renewable capabilities.The brushless doubly-fed induction generator’s operation mode is similar to the doubly-fed induction generator,which is widely used for wind turbine system.The Brushless Doubly-Fed Induction Generator can operate in doubly-fed mode without electrical brush and slip ring.Therefore,the BDFIG has a great prospect in wind power generation.The research on structure and control strategy of BDFIG has become the studying hotspot.With the development of the latest 10 years,the Brushless doubly-fed induction generator has entered the market of wind power generation gradually.Due to the instability and the improved permeability of wind power generation system,the power system makes large amount of compulsory requests for the grid-connected wind turbine systems.After the Low voltage ride through requests,the power system has promoted the High voltage ride through requests,which is more challenging.So far,the High voltage ride through methods of BDFIG have not been found in literatures.Based on the above problem aiming at BDFIG,this thesis does the main work as follows:1.This paper applied the flux linkage tracking control strategy to solve the problems of the HVRT issues for brushless doubly-fed induction generator.In the condition of considering the rotor resistance of BDFIG,the regarding theoretical analysis is completed.The results between theoretical deduction and simulation are corresponding.This sector promoted theoretical foundation for the promotion of modified flux linkage tracking control strategy.2.Aiming at the problem of the power winding(also known as PW)active power is uncontrollable when utilizing the traditional control strategy,this paper promoted the symmetrical high voltage ride through control method for BDFIG based on modified flux linkage tracking control strategy.This method draw into the controlling parameter compensating angle.In this way,the PW active and reactive power during the HVRT state period could be controlled,therefore the HVRT capability of BDFIG could be improved.3.This paper applied the traditional and modified flux linkage tracking control strategy to solve the issues of asymmetrical high voltage ride through method for BDFIG.This paper accomplished the work of analytical deduction and simulation for the asymmetrical HVRT of single-phase voltage swell fault and two-phase voltage swell fault.The simulation results in MATLAB/Simulink matched the analytical results,which can suppress the PW average power to zero to meet the Jordan HVRT standard.The simulation results provided the foundation to research on asymmetrical high voltage ride through method in the future.4.This paper promoted a kind of grid voltage’s asymmetrical fault detection method based on variable-step LMS adaptive notch filter algorithm.The regarding theoretical analysis,theoretical deduction and simulation works were done.The results of theoretical analysis and simulation presented that the method promoted by this paper could detect the asymmetrical fault by detecting the negative-sequence component of grid voltage.This method provided the foundation for the research on asymmetrical high voltage ride through method.5.Aiming at accomplishing the experiments of asymmetrical HVRT method for BDFIG,this paper developed a kind of symmetrical voltage swell fault equipment based on the principle of impendence voltage divider.The development of circuit topology,parameter designation,simulation work,development of equipment platform and experiments were completed.The experimental results presented that the symmetrical voltage swell fault can be simulated,which provided the foundation to the HVRT experiments in the future.6.This paper developed a kind of asymmetrical voltage swell fault generator based on AC contactless switch and grid phase detecting method.The regarding designation,theoretical analysis and simulation works were done,which provided foundation to the development of hardware system and the experimental work in the future.7.Aiming at testifying the feasibility of traditional and modified flux linkage tracking control strategies,this paper accomplished the experimental works on the basis of the experimental platform of 15KW Brushless doublyfed induction generator and symmetrical voltage swell fault generator.The condition of experiment was full-load,rated voltage,the highest speed and highest voltage swell fault degree.The experimental results meet the Jordan HVRT standard,which can be matched with the results of theoretical analysis and simulation.