Position Sensor Fault Tolerant Technology On Direct-Drive Wind Turbine

Most of the wind turbines have been installed in remote areas, such as grassland,seaside. Wind turbines’ each downtime will bring very big loss to power and owner,therefore improving the fault tolerant ability of wind generator unit is very helpful on faultoperation. According to statistics, the sensor or actuator faults resulted in a80%controlsystem collapse.The control strategies of PMSG machine side converter in engineering applicationare based on various types of sensors working Normally, a position sensor is one of them.The research of generator rotor position estimation techniques can not completely replacethe running performance of physical sensors. Therefore in the engineering application, Wemust stop the machine and overhaul, if the position sensor fault, and it will inevitablybring losses. In order to improve the fault tolerance ability of direct-drive wind turbine, adynamic reconfigurable control strategy of machine-side converter control system wasproposed in this paper. According to the state changing of rotor position sensor, mode ofencoder and sensorless are reconstructed dynamically in control system. In this paper mymain work are:1. A position sensor fault tolerant control agencies for permanent magnetsynchronous wind turbine machine-side converter controller was built, and the role andstructure of the fault monitoring unit and fault-tolerant control unit in the agency wasanalyzed.2. The mathematical model of permanent magnet synchronous generator in differentcoordinate system were established to lay the foundation of the id=0vector control. theMachine side converter was control by SVPWM technique. Then the model in theSimulink environment was built to validation control algorithm’s feasibility.3. An estimation of permanent magnet synchronous generator was got by pure digitalphase-locked loop technique. and estimate method of the constant amplitude voltagevector and the constant width voltage pulse which were applied in the permanent magnetsynchronous motor initial position was analyzed. Model in the Simulink environment wasbuilt to validate the digital phase-locked loop speed estimation technology is feasible, andestimation error both on the static and dynamic were analyzed.4. The generator position sensor state monitoring point velocity was got by theLagrange interpolation polynomial and RBF neural network combination method. The speed estimation and sensor detection value error were combined to detect position sensorstatus.5. The status of position sensor was determined to start the reconstruction. Valid datasbefore fault were used to calculate the speed of the point of failure by lagrangeinterpolation polynomial, and moved closer to the estimated speed value with maximumspeed difference does not affect the stability of the system until equal, in order to achievethe consistency and continuity of the dynamic reconfiguration process. The feasibility ofthe theory was verified with Matlab simulation and experiment.