Research On Reliability Of Full Power Converter For Permanent Magnet Direct-driven Wind Turbine

Wind turbine reliability is a key issue affecting the rapid development of wind power generation, Reducing gearbox required complex maintenance and long downtime, direct-drive wind turbine generator has been more widely applied. However, due to the high failure of the converter system, so the reliability of the direct-drive wind turbine generator system has been a hot topic. This paper presents a reliability issues study of the direct-drive wind turbine generator-side converter system, researching on the whole system reliability and fault diagnosis algorithm. Main contents include as follows:Firstly, according to the true maintenance statistics information important data, reliability block diagram (RBD) on whole system set up by Reliasoft Software. Based on the reliability model, forecasting analysis the reliability of two different kinds of wind turbine, and the subsystem reliability importance. Similarity, quantitative reliability analysis on the fault tolerant topology is also used the RBD modeling. From the simulation results, RBD modeling can help the operators and professionals in wind energy industry predict the life of wind turbine. Secondly the direct-drive permanent magnet synchronous wind generator system simulation model is established on Matlab/Simulink platform, studies the dynamic operation characteristics under variable wind speed. The optimal tip speed ratio based maximum power point tracking control is utilized to ensure the maximum power capture for the system.The field oriented control algorithm is applied to control the speed of the PMSG with the reference of the wind speed. The simulation results show that the model has good dynamic response characteristics, so a platform for fault diagnosis has been established. Using the current track method collects the fault characteristic for diagnosing the IGBT open fault based on simulation model. Because the dynamic and complexity of wind speed, a new method called normalized current track is proposed for diagnosing in the state of variable wind and high frequency noise. The method based on wind speed corresponding to the current amplitude of Park transformation as a normalized value can apply in the wind turbine system. Simulation results present the proposed strategy allow the effect of the variable wind and the high frequency noise. Lastly, by collecting different rotor speed corresponding to the fault trajectory so as to normalizing respectively in fault simulation experiment platform and displaying in Labview graphical interface, the study implements and proves the primary application of the fault diagnosis algorithm.