Research On Open-circuit Fault Diagnosis Of Direct-drive Permanent Magnet Synchronous Wind Power System Converter

Wind power generation is an important part of renewable energy generation.As the industry develops,it still faces major development opportunities and difficult challenges.The full power converter is the core component and weak link of the direct drive permanent magnet synchronous wind power generation system.The failure of the converter will cause the system to run disorderly and affect the system reliability.Research on the open circuit fault diagnosis of wind turbine converters has received more and more attention.This paper studies the open circuit fault diagnosis of the machine side converter of direct drive permanent magnet synchronous wind power generation system.Firstly,the paper analyzes the operating principle of direct-drive permanent magnet synchronous wind power generation system,and builds a mathematical model of permanent magnet synchronous generator based on maximum power point tracking control and zero d-axis current control.The mathematical model of full power converter and the space vector modulation strategy are introduced.The conduction relationship and sector vector variation of the rectifier under the open circuit fault of the machine side rectifier power switch are analyzed,and the fault phenomena such as missing current waveform,generator torque fluctuation and generator speed fluctuation under the fault are summarized.Combined with the Matlab/Simulink simulation model,the operation characteristics of the single-tube fault and double-tube fault of the rectifier are analyzed and verified.According to the operating characteristics of direct-drive permanent magnet synchronous wind power generation system,open circuit fault diagnosis method based on angle comparison and open circuit fault diagnosis method based on real-time current amplitude are proposed.The basic principles of diagnostic methods,threshold parameter selection,and diagnostic implementation are described.The simulation model is used to verify the diagnostic ability and diagnostic accuracy of the two diagnostic methods for different fault types.A machine-side simulation experiment platform for a direct-drive permanent magnet synchronous wind power generation system was built.The open circuit fault characteristics of the power switch tube are verified,and the operational results of the experimental platform are used to verify the effectiveness of the angle-based fault diagnosis method and the real-time current amplitude diagnosis method.Compared with the existing fault diagnosis methods,the diagnostic capabilities under different fault types are compared.The comparison shows that the diagnostic speed and accuracy of the proposed diagnostic methods are significantly improved.