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Passivity-Based Control of Electric Machines

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Passivity-Based Control of Electric Machines PER JOHAN NICKLASSON I_N0~7 NO970521? PASSIVITY-BASED CONTROL OF ELECTRIC MACHINES RECEIVED DOKTOR IN GENI0RAVHANDLIN G 1996:21 INSTTTUTT FOR TEKNISK KYBERNETIKK NTM TRONDHEIM UNIVERSITETET I TRONDHEIM NORGES TEKNISKE H0GSKOLE ITK-rapport 1996:17- W Passivity-Based Control of Electric Machines Thesis by Per Johan Nicklasson Submitted In Partial Fulfillment of the Requirements for the Degree of Dr.ing. Report 96-17-W Department of Engineering Cybernetics Norwegian University of Science and Technology N-7034 Trondheim, Norway 1996 DiSmaUTTON OF TBS DOCUMENT * WNUM1TED DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document Abstract This thesis presents new results on the design and analysis of controllers for a class of electric machines. Nonlinear controllers are derived from a Lagrangian model representation using passivity techniques, and previous results on induction motors are improved and extended to Blondel-Park transformable machines. The relation to conventional techniques is discussed, and it is shown that the formalism introduced in this work facilitates analysis of conventional methods, so that open questions concerning these methods may be resolved. In addition to the new controllers derived for a class of electric machines, this work contains the following improvements of previously published results on control of induction motors: • The improvement of a passivity-based speed/position controller. • The extension of passivity-based (observer-less and observer-based) con­ trollers from regulation to tracking of rotor flux norm. • An extension of the classical indirect FOC scheme to also include global rotor flux norm tracking, instead of only torque tracking and rotor flux norm regulation. Experimental results from applications of the proposed control schemes to a squirrel- cage induction motor are included to illustrate the design. These results show that the proposed methods have advantages over previous designs with respect to con­ troller tuning, performance and robustness. The main results in this thesis have been presented at international conferences, and parts of this work have also been published in international journals. i Abstract Preface and Acknowledgments This thesis is submitted in partial fulfillment of the requirements for the degree of Dr.Ing. (Doktor ingeni0r ) at the Norwegian Institute of Technology 1 (NTH), documenting the research part of my work towards this degree. The work has been carried out at Department of Engineering Cybernetics, during the period February 1992 to January 1996. It has been financed first by NTH during the period I worked as a teaching assistant (1992-1993), and then by a scholarship from The Research Council of Norway (February 1993 to January 1996), under grant 100651/410. I am grateful to my supervisor Professor Dr.Ing. Olav Egeland for encouraging me to work towards a doctoral degree after finishing my M.Sc. in 1991. His enthusiasm has been a valuable source of inspiration and motivation during this work, and he has convinced me that I should always have confidence in what I do, and take a rigorous attitude to any control problem, even if it may seem “obvious ” at the first glance. For increased competence at our department, he has always insisted in contact with leading international researchers and their organizations, and in 1992 he introduced me to CNRS Researcher Dr. Romeo Ortega, Universite de Technologic de Compiegne (UTC), France, who later became my co-supervisor. I would like to thank Dr. Ortega for his skillful advising during this project. He introduced me to the field of electric machines and passivity-based control, and main parts of the theoretical results in this thesis were initiated during a stay at UTC under his supervision from March to July 1994. This cooperation continued after I returned, and resulted in several joint publications. His optimism and diligent care about every technical difficulty have been especially valuable, and I hope some of it will follow me for use in my future work. Several people have helped me with this work in various ways — only a few thanks are listed below: • Professor Gerardo Espinosa-Perez at Universidad National Autonoma de 1From January 1996 this institute has been an integrated part of the Norwegian University of Science and Technology (NTNU). ill IV Preface and Acknowledgments Mexico (UNAM), for stimulating discussions and joint work. It has been a pleasure to work with him. • A. Loria, D. Taoutaou and K. Kim, for stimulating discussions and help during my stay in Compiegne. • The M.Sc. students J.G. Dyrset, H. Holemark, and L.F. Markussen, for doing their thesis under my guidance. I hope they have benefited as much from this cooperation as I have. • My colleagues in the Motion Control Group, supervised by the Professors Egeland and Fossen, for creating a very pleasant environment for research. I would especially like to thank Morten Dalsmo, John-Morten Godhavn and Erling Aarsand Johannessen for many useful comments to this work and numerous discussions in general control theory (and theory in general!). • The staff at our electromechanical workshop, S. Bertelli, T. Haugen, A. Ler- vold, and P.I. Lovold, for helpful comments and suggestions based on years of experience to the practical part of this work — the building of the induction motor setup. The combination of power electronics and signal transmission was a bit tricky, and a considerable amount of work which is difficult to document in a thesis, had do be done. Comments and suggestions from A. Fritzsche at Lust Antriebstechnik GmbH, Lahnau, S. Beineke at Universitat Gesamthochschule Paderborn, and J. Vater at the dSPACE Company, have also been of high importance for the success of this part. Finally, I would like to express my gratitude to The Center of Maritime Control Systems at NTH and SINTEF, headed by Professor Egeland, for financial support to attend conferences in Orlando (CDC ’94), Seattle (ACC ’95), Rome (ECC ’95) and New Orleans (CDC ’95). These conferences have been important not only for the presentation of this work, but also for making international research contacts. Trondheim, February 29, 1996 Per J. Nicklasson Contents Abstract i Preface and Acknowledgments iii List of Figures xi Nomenclature xiii 1 Introduction 1 1.1 Motivation ..................................................................................................... 1 1.2 Previous Work.............................................................................................. 5 1.2.1 Exact Linearization Design ......................................................... 7 1.2.2 Backstepping and Manifold Designs .................... 9 1.2.3 Energy-Shaping Design ............................................... 13 1.2.4 Other Results.................................................................................... 15 1.3 Unresolved Problems.................................................................................... 15 1.4 Contributions of this Thesis....................................................................... 17 1.5 Outline of the Thesis . .............................................................................. 18 2 Control of The Generalized Electric Machine 19 2.1 Introduction ..................................................................................................... 19 2.2 Passive Subsystems Feedback Decomposition ....................................... 20 v vi ■ Contents 2.3 Generalized Rotating Electric Machine................................................... 22 2.3.1 Model.................................................................................................. 22 2.3.2 Remarks to the Model.................................................................... 24 2.3.3 Examples........................................................................................... 27 2.4 Problem Formulation and Design Procedure......................................... 28 2.4.1 Problem Formulation ................................................................... 28 2.4.2 Design Procedure.............................................................................. 28 2.5 Strict Passifiability via Damping Injection............................................ 29 2.5.1 Feedback Decomposition ................................................................ 29 2.5.2 Conditions for Damping Injection............................................... 29 2.5.3 Remarks to Conditions for Damping Injection........................ 31 2.6 Current Tracking via Energy-Shaping ................................................... 32 2.7 From Current Tracking to Torque Tracking ......................................... 33 2.7.1 Desired Current Behavior . ................................................... 34 2.7.2 Decoupling Conditions ............................................................ 34 2.7.3 Remarks to the BP Transformation ......................................... 36 2.8 Main Results.................................................................................................. 37 2.8.1 Underactuated Machines, ns <ne ............................................ 37 2.8.2 Fully Actuated Machines, ns = ne............................................ 39 2.8.3 Remarks............................................................................................... 40 2.9 Examples........................................................................................................
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