Fault-tolerant Control of a Wind Turbine with Generator Stator Inter-turn Faults (2013)

AbstractFaults of wind turbine generator electromechanical parts are common and very expensive. This paper introduces a generator fault-tolerant control scheme for variable-speed variable-pitch wind turbines that can be applied regardless to the AC generator used. The focus is on generator stator isolation inter-turn fault that can be diagnosed and characterised before triggering the safety device. An extension of the conventional wind turbine control structure is proposed that prevents the fault propagation while power delivery under fault is deteriorated as less as possible compared to healthy machine conditions. Fault-induced and inherent asymmetries of the generator are estimated and respected by the field-oriented control of the generator to eliminate torque oscillations. An approach for asymmetry detection based on an unscented Kalman filter is proposed. Presented fault-tolerant control strategy is developed taking into account its modular implementation and installation in available control systems of existing wind turbines to extend their exploitable life span and increase energy production. Simulation results for the case of a megawatt class wind turbine are presented.Kvarovi elektromehaničkih dijelova generatora vjetroagregata česti su i izrazito skupi. U ovom radu predstavljen je koncept na kvarove otpornog upravljanja generatorom vjetroagregata s promjenjivom brzinom vrtnje i zakretom lopatica primjenjiv bez obzira na tip korištenog izmjeničnog generatora. Naglasak je stavljen na oštećenje izolacije unutar namota jedne faze statora generatora koje se može dijagnosticirati i okarakterizirati prije aktiviranja sustava zaštite. Predložena je nadogradnja postojećeg sustava upravljanja vjetroagregatom koja sprječava širenje kvara i pritom postiže čim manje smanjenje proizvodnje električne energije u odnosu na normalan režim rada. Također je prikazano vektorsko upravljanje generatorom koje uzima u obzir nesimetrije generatora, kako one nastale uslijed djelovanja kvara, tako i one inherentne. U radu je prikazan pristup za otkrivanje nesimetrija generatora zasnovan na nederivacijskom Kalmanovu filtru. Predstavljena strategija upravljanja razvijena je uvažavajući mogućnost modularnog nadovezivanja na postojeće algoritme upravljanja već postavljenih vjetroagregata s ciljem produženja njihova životnog vijeka i povećanja proizvodnje energije. Dani su simulacijski rezultati za slučaj vjetroagregata iz megavatne klase.Key words: Wind turbine controlGenerator fault-tolerant controlStator winding isolation faultNonlinear estimationAsymmetric field-oriented controlKljučne riječi: upravljanje vjetroagregatomupravljanje otporno na kvarove generatorakvar izolacije statorskog namotanelinearna estimacijavektorsko upravljanje nesimetričnim strojem Additional informationNotes on contributorsVinko LešićVinko Lešić received his master degree in electrical engineering and information technology from University of Zagreb Faculty of Electrical Engineering and Computing (UNIZG-FER) in 2010. Currently, he is with the Department of Control and Computer Engineering at UNIZG-FER where he is pursuing his PhD degree. His research interests are in the area of control theory with application to advanced control of electrical drives and wind turbine generators.Mario VašakMario Vašak is an Assistant Professor at the Department of Control and Computer Engineering of University of Zagreb Faculty of Electrical Engineering and Computing (UNIZG-FER). He received his PhD degree in Electrical Engineering from UNIZG-FER in 2007. He works in the areas of predictive/robust/fault-tolerant control and computational geometry applied to them, in the following application domains: renewable energy systems, water management systems, energy-efficient buildings, energy-efficient railway transportation and automotive systems. On behalf of UNIZG-FER he led an FP7-SEE-ERA.net PLUS research project MONGS on generator-fault-tolerant control in wind turbines, and currently he is UNIZG-FER leader of the FP7-STREP UrbanWater that deals with fresh water supply system management in urban environments. He published over 40 papers in journals and conference proceedings.Nedjeljko PerićNedjeljko Perić received the B.Sc., M.Sc. and Ph.D. degrees in Electrical Engineering from the University of Zagreb Faculty of Electrical Engineering and Computing (UNIZG-FER) in 1973, 1980, and 1989, respectively. From 1973 to 1993 he worked at the Institute of Electrical Engineering of the Končar Corporation, Croatia, as an R&D engineer, Head of the Positioning Systems Department, and Manager of the Automation Section. In 1993 he joined the Department of Control and Computer Engineering at FER Zagreb as an associate professor. He was appointed as a full professor in 1997 and since 2010 he serves as UNIZG-FER dean. His current research interests are in the fields of process identification and advanced control techniques. In periods 1992–1998 and 2000–2011 he served as the Chairman of KoREMA, the Croatian Society for Communications, Computing, Electronics, Measurements and Control. He is also a member of several international professional associations. Professor Perić is a Fellow of Croatian Academy of Engineering.Gojko JoksimovićGojko M. Joksimović received PhD degree and the Full Professor degree from University of Montenegro, Montenegro, in 2000 and 2011, respectively. His main research areas include analysis of electrical machines, condition monitoring of electrical machines, and power electronics and control. He is the author of a few books and more than 50 papers published in leading international scientific journals and international conferences.Thomas M. WolbankThomas M. Wolbank received the doctoral degree and the Habilitation from Vienna University of Technology, Vienna, Austria, in 1996 and 2004, respectively. Currently, he is with the Department of Energy Systems and Electrical Drives, Vienna University of Technology, Vienna, Austria. He has co-authored some 100 papers in refereed journals and international conferences. His research interests include saliency-based sensorless control of AC drives, dynamic properties and condition monitoring of inverter-fed machines, transient electrical behavior of AC machines, and motor drives and their components and controlling them by the use of intelligent control algorithms.