Fault-tolerant Control of a Wind Turbine with a Squirrel-cage Induction Generator and Rotor Bar Defects (2013)

AbstractWind turbines are usually installed on remote locations and in order to increase their economic competence malfunctions should be reduced and prevented. Faults of wind turbine generator electromechanical parts are common and very expensive. This paper proposes a fault-tolerant control strategy for variable-speed variable-pitch wind turbines in case of identified and characterised squirrel-cage generator rotor bar defect. An upgrade of the torque control loop with flux-angle-based torque modulation is proposed. In order to avoid or to postpone generator cage defects, usage of pitch controller in the low wind speed region is introduced. 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 life cycle and energy production. Practical implementation aspects such as estimation of variables used in control and estimate errors are considered and respected in operation, as well as fault-induced asymmetries. Simulation results for the case of a megawatt class wind turbine and the identified rotor bar fault are presented.Vjetroagregati se obično postavljaju na udaljene nepristupačne lokacije teje potrebno spriječiti nastanak kvarova da bi se povećala njihova ekonomska konkurentnost. Kvarovi elektromehanickih dijelova generatora vjetroagregata česti su i vrlo skupi. U ovom radu predstavljen je koncept upravljanja vjetroagregatima s promjenjivom brzinom vrtnje i zakretom lopatica za slučaj identificiranog i okarakteriziranog oštećenja kaveza asinkronog generatora. Predložena je nadogradnja na postojeći algoritam upravljanja momentom zasnovana na njegovoj modulaciji s obzirom na položaj magnetskog toka generatora. Da bi se izbjeglo ili usporilo širenje napuknuća kaveza generator predložena je primjena regulacijskog kruga za zakret lopatica i u režimu rada vjetroagregata ispod nazivne brzine vrtnje. Predstavljena strategija upravljanja razvijena je uvažavajući mogućnost modularnog nadovezivanja na postojeće metode upravljanja već postavljenih vjetroagregata s ciljem produženja njihova životnog vijeka i povećanja proizvodnje energije. Razmatrani su i uvaženi aspekti vezani uz praktičnu izvedbu kao što je estimacija varijabli korištenih u upravljačkom algoritmu i pripadajuće pogreške estimate, kao i nesimetrije uzrokovane nastankom kvara. U radu su dani simulacijski rezultati za slučaj vjetroagregata iz megavatne klase s dijagnosticiranim napuknućem kaveza rotora.Key words: Wind turbine controlTorque controlGenerator fault-tolerant controlNonlinear estimationAsymmetric field-oriented controlKljučne riječi: upravljanje vjetroagregatomupravljanje momentomupravljanje otporno na kvarove generatoranelinearna estimacijavektorsko upravljanje nesimetričnog stroja 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 50 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 UNIZG-FER 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 Peric is a Fellow of Croatian Academy of Engineering.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 inverterfed machines, transient electrical behavior of AC machines, motor drives and their components as well as controlling them by the use of intelligent control algorithms.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.