Research On Fault Characteristics And Diagnosis Method Of Wind Turbine Converter

Under the global energy revolution,wind energy has become one of the most important energy sources.With the increasingly serious environmental problems,countries begin to attach importance to the development of wind power generation in the world,so wind power generation has developed rapidly in recent years.With the increasing capacity of wind turbines connected to the grid,the interaction between the grid and wind turbines becomes more and more important,and the wind turbines are connected to the grid through full-power converters.Power electronic converter can realize wind energy efficient and stable grid-connected,and has been widely used in wind power generation system.Considering the bad operating environment of wind power system,the damage of components caused by long-term operation of converter will lead to serious accidents,especially IGBT open circuit fault is the most serious one.Therefore,it is very important to judge the fault of converter quickly and take effective protection measures for the stable operation of wind power system.Firstly,in this paper,the power converter in permanent magnet direct drive wind power generator is taked into consideration,and the key technology of converter internal IGBT open circuit fault diagnosis is studied.The components of permanent magnet direct drive wind power generation system,including wind turbines,permanent magnet synchronous generators,wind power converters are studied,focusing on the topology,basic principles and control methods of wind power converters,providing a theoretical basis for the follow-up study of wind power converter fault characteristics.Secondly,the basic principle of open-circuit faults of wind power converters is analyzed theoretically,and the open-circuit faults of wind power converters are sort according to the characteristics of the faults.The MATLAB/Simulink simulation is carried out to study the open-circuit faults of grid-side converters and machine-side converters respectively,and the characteristics of open-circuit faults are extracted,including current waveform and electricity.Pressure waveform,active power waveform and reactive power waveform.Finally,based on the analysis of positive and negative sequence components of three-phase fault current,the feature extraction method of IGBT open-circuit fault of wind power converter is studied.The amplitude of positive and negative sequence current components is used as the training sample of wavelet neural network,which reduces the number of samples,improves the learning efficiency and has better fault resolution.Based on the information of three-phase fault current direction and zero-crossing point,an open-circuit fault diagnosis and location method of wind power converter based on wavelet neural network algorithm is proposed.The validity of the proposed fault diagnosis method is verified by an example.