**EPE
Association & Swiss Federal Institute of Technology**

T1
: |
Vector control of induction motor
drives: understanding based on physical principles and
PSpice-based modelingby Prof. Ned Mohan |

**Objectives**

The objective of this tutorial is to simplify the understanding of vector control in induction-motor drives, based on physical principles. PSpice-based modeling will be used to describe the effect of de-tuning on the drive performance.

**Intended for**

This tutorial is primarily intended for practicing engineers, educators and student with no prior familiarity with vector control of induction motor drives. However, even those with advanced understanding of drives will find this tutorial very useful.

**Content**

Applications of electric drives are growing very rapidly. This growth is primarily in drives using induction motors that enjoy the advantages of low cost, and rugged construction compared to other machines. Vector control can emulate the performance of dc motors and brush-less dc motors, without their associated drawbacks.

In this tutorial, basic principles are first used to provide a qualitative understanding of vector control. It is shown that with vector control, an induction machine almost instantaneously transitions from one steady state to another steady state, while delivering a step-change in torque. Therefore, a vector-controlled induction machine can be modeled based on steady state analysis. In view of its application to describe vector control, the steady state analysis is carried out by representing magnetic-field distributions in the air gap by space vectors.

**Tutorial
Notes**

A copy of the overhead transparencies used for tutorial presentation will be provided, in addition to a complete, stand alone set of notes which are derived from a soon-to-be-published book.

**Course
Faculty**

Dr. Ned Mohan, Oscar A. Schott Professor of Power Electronics, University of Minnesota, USA

**Biography**

Dr. Ned Mohan has been with the University of Minnesota since 1976 where he is a professor of electrical and computer engineering and holds Oscar A. Schott Chair in power electronics.

He is a co-author of a widely-used textbook on Power Electronics (co-authored with Professors Tore Undeland and William P. Robbins) which has also been translated into several languages.

Recently, in addition to his research activities, he is developing educational material and laboratories for courses in power electronics and motor drives. This effort is sponsored by the National Science Foundation.

Prof. Mohan is a Fellow of the IEEE.

T2
: |
Design of
mechatronic systemsby Dr S. Colombi |

**Abstract**

"Mechatronics" is a rapidly growing field, resulting from the combination of classical electrical engineering, mechanical engineering and computer science.

Mechatronics deals then with all the problems for which an
efficient solution (i.e. more performant and/or cheaper) can be
found by combining the three fields. The key point is that a
mechatronics solution must improve the classical mechanical
solution. The aim of this tutorial is to give an overview of the
mechatronics design of a system, i.e. how to improve the
mechanical solution using actuators, sensors, electronics and
control algorithms. The latter are a typical feature of a
mechatronic system and can be considered as "the heart of
the system". In fact, thanks to the considerable advances in
the microelectronics field, it is now possible to include more
and more cheap intelligence in a system. The lecture is based on
several real application examples that illustrate the various
features of the mechatronics design and that are an important
source of inspiration for many other applications. A design is
always a "question of compromise" requiring a careful
balancing of different parameters: mechanical system, actuators
(motors + gearboxes), power supply, sensors, control algorithms,**
**hardware and software architecture. A system design is the
key of success. There is always a multitude of different
solutions for a given problem. The art of the mechatronic
designer consists in striking the best compromises that optimise
the global system. For this, a methodology is outlined based on
the diagram of influence and on mechanical equivalents that allow
an intuitive comprehension of complex systems. The simulation is
also very effective. For mechatronic systems, the Matlab/SimulinkÔ and SimplorerÔ
packages are particularly well suited and their utility will be
demonstrated in the presented application examples.

**Intended for**

The course is intended for design engineers, industry application engineers and researchers working in the field of mechatronics, motion control and system design or willing to introduce them to this rapidly growing field which concern more and more industrial products.

**Programme**

09.00-09.30 | IntroductionDefinition, functions and solutions, examples of mechatronic systems. |

09.30-10.30 | Specification and design
of mechatronic systemsDirect and inverse problem, design of mechatronic systems (cost, performances, system approach, diagram of influence, design steps, simulation and design tools), mechanical equivalents. |

10.30-11.30 | Mechanical aspects and
mechanical systemsModelling: force/torque balance approach or energy based approach, examples of mechanical systems, oscillating systems, mechanical friction, stick-slip. |

11.30-12.30 | Command and control
aspectsThe control, heart of the mechatronic system, bandwidth of a control, multivariable description of the mechanical system, control structure with non linear feedback, additional problems (sampling and quantisation, small time constants, structure and parameter uncertainties, disturbances, limitations). |

12.30-13.30 | Lunch Break |

13.30-14.30 | Numerical simulationGeneral considerations (modelling, quantisation and numerical problems), overview of Matlab/Simulink and Simplorer (characteristics and special features, advantages and drawbacks). |

14.30-18.00 | Selected application
examples (depending on the audience interests) Master-Slave force reflecting servomechanisms (45’), Actuators and controls for a master-slave force reflecting servomanipulator (30’), Electronic stiffening of mechanical transmissions (30’), Electronic stiffening and linearisation of actuators; control of the JET Boom (45’), Electronic compensation of the parasitic torques of brushless DC motors (30’), Magnetic levitation and lateral guidance of a vehicle (45’), Control of a parallelogram robot (45’), Automotive applications (45’) For each application example, the teaching include a theoretical part (modelling, control design) followed by the validation in simulation on a PC. |

17.45-18.00 | Concluding discussion |

**Course
Faculty**

Dr S. Colombi - IMV Invertomatic Technology SA, Switzerland

**Biography**

Silvio Colombi is born in Locarno (Switzerland) in 1959. MSc in Electrical Engineering of the Swiss Federal Institute of Technology (EPFL) in 1983 and PhD in 1987. As assistant then 1rst assistant at the Industrial Electronics Laboratory (LEI), he has worked on and lead numerous industrial and research projects. He has worked at JET (Joint European Torus) in Abingdon (UK) on teleoperation problems in 1990 as Associated Staff and in 1993/1994 as TeleMan Fellow. He has negotiated and carried out several European projects and many consultations for the industry. In 1994, he is scientific associate at the LEI and leads the mechatronics group. In 1996, he is lecturer of mechatronics at the EPFL and works as a part time independent consultant for the SMH Automobile in Bienne. In 1998, he joins IMV Invertomatic Technology in Riazzino as responsible for the development of new technologies. He is the author of some industrial patents and about 30 publications dealing with modelling, simulation, control, mechatronics and industrial electronics.

T3
: |
Flexible alternative current
transmission systems - Power systems approach - State of
the artby Prof. M. Crappe, Prof. K. L. Lo, Prof. A. Rufer and Prof. J. Trecat |

**Objectives**

This one-day tutorial is in relation with topic 9 « Power electronics in Generation, Transmission and Distribution » and more particularly the topics 9c and 9g.

It aims at giving an introduction for non power systems specialists to new appealing systems (FACTS) promised to a large development in the near future in electric utilities.

It will also present the state of the art based on existing devices, projects and investigations through simulations. The emerging issues and the prospects in the fields of power electronics components, inverter structures (as multilevel inverters) and advanced control techniques (as ANN) will be discussed.

**Programme**

**8.30 - 10.30 Introduction to the FACTS** – *Prof.
M. Crappe and Prof. J. Trecat*

Power system essential

Meshed network computatiuon (load flow, power loop, …)

Voltage and frequency control

Dynamic behaviour of the generators

Transient and dynamic stability

Recent trends in the power system evolution and FACTS

Extension of the interconnections, power exchange increasing, ecological opposition to new lines and new power stations, deregulation of power markets, European Community policy

Description of power electronics controllers

Systems based on thyristors

SVC (static var compensator)

TSSC (thyristor switched series capacitor)

TCSC (thyristor controlled series capacitor) or ASC (advanced series compensation)

Thyristor phase shifter

Systems based on IGBT, GTO or IGCT

ASVC (advanced static var compensator) or STATCOM

UPFC (unified power flow controller)

Survey of the existing applications

**10.30 - 11.00 coffee break**

**11.00 - 12.30 Simulation and control of FACTS **– *Prof.
K. L. Lo*

This part is dealing with the modelling of UPFC and the coordinate of multiple UPFCs for steady state system operation with the help of ANN. The tutorial will proceed to use multiple FACT devices, multiple TCSCs, for improvement of dynamic stability of power system. The coordination of these devices will be centered on the use of fuzzy logic controllers.

**14.00 – 15.30 ****State of the art **–
*Prof. A. Rufer*

State of the art and prospects in power electronic components (thyristor, GTO and IGCT), emphasis will be put on IGCT.

Survey of the possible structures of converters in large power and high voltage applications.

**15.30 – 16.00 coffee break**

**16.00 – 17.30 ****Numerical simulation
demonstrations**

(EUROSTAG, EMTDC, SIMSEN, SABER, …)

Discussions

**Intended for**

Tutorial devoted to power electronic engineers needing to understand the pecularities of power system behaviour, justifying fast power electronics control means.

**Course
faculty**

Prof. M. Crappe and Prof. J. Trecat, Faculté Polytechnique de Mons, Belgium ; Prof. K.L. Lo, University of Strathclyde, United Kingdom and Prof. A. Rufer, EPFL, Switzerland

**Biography**

Michel Crappe (1936) received his degrees in Civil Mining and Civil Electrical Engineering in 1959 and 1962 respectively, from the Faculté Polytechnique de Mons (Belgium). After three years at Corps des Mines in Belgium he joined the Faculté Polytechnique de Mons in 1963 where he has been full professor in charge of the Electrical Machines Department since 1971. Author and co-author of 75 scientific papers, his research areas include electrical machines development, system identification concepts, and particularly the dynamic behavior of large synchronous machines in the power systems. Since 1982, he also teaches Electrical Machines in Ecole Nationale Supérieure d’Ingénieurs de Valenciennes (France). He is a member of the AMPERE Commission created in Belgium by Minister of Energy in order to study the problem of electrical energy generation in the future.

He is member of the IMACS TC1, and EPE, Steering Committees, and also of EPE Executive Council. Prof. M. CRAPPE has been on the Editorial Boards of the Electrical Power Engineering (ETEP), Electromotion et Revue Internationale de Génie Electrique since their launching respectively in 1991, 1994 and 1998. Recipient of the 1998 PES Prize Paper Award of IEEE. He is member of CIGRE, EPE, IMACS, SEE (Senior Member) and of several Scientific Committees in Belgium and in France.

J. Trécat, IEEE Senior Member, graduated from Faculté Polytechnique de Mons in 1963 and received his PhD degree from UMIST (UK) in 1970. He is now Professor of Power Systems in the Electrical Engineering Department of Faculté Polytechnique de Mons. He is author and co-author of several papers in Power Systems.

T4
: |
Matrix converter technologyby Dr Patrick Wheeler
and Dr Jon Clare |

**Summary**

The matrix converter permits direct AC-AC power conversion without an intermediate DC link and therefore represents an "all silicon" solution as the power converter for variable speed AC drives. Compared to conventional drives there is potential for reduced cost of manufacture and maintenance, and increased power/weight and power/volume ratios. The circuit is inherently capable of bi-directional power flow and also offers virtually sinusoidal input current, without the harmonics usually associated with present commercial inverters. This tutorial will present the current status of matrix converter technology and discuss existing solutions to the technical challenges that must be addressed before full commercial exploitation of the circuit can be achieved.

**Content**

Recently there has been considerable industrial interest in the use of matrix converters for a wide range of applications. These include low power applications such as integrated drives and higher power ones such as marine propulsion. In many of these situations the advantages offered by the matrix converter circuit outweigh the perceived problems and actual technical challenges. The tutorial is therefore very topical and timely.

The tutorial will:

- introduce the matrix converter idea and develop an understanding of the basic concepts
- outline the advantages of the matrix converter over existing solutions
- identify commonly perceived and actual limitations of the matrix converter
- investigate converter waveform quality and input filter design
- explore solutions to the switch current commutation problem
- discuss matrix converter modulation strategies and their implementation
- consider the future potential and applications of matrix converter technology

The tutorial will use appropriate practical results from various prototype matrix converters to illustrate the topics under discussion. These results will be backed up with simulation studies and design curves where appropriate.

**Introduction to Matrix Converters***- Dr Jon Clare and Dr Pat Wheeler*

- The basic concepts
- Introduction to mathematical framework
- Examples of typical operating characteristics and waveforms
- Potential advantages of matrix converter technology
- Perceived and theoretical limitations
- Technical challenges
- Historical development and key publications

**Power Circuit Implementation***- Dr Pat Wheeler*

- Bi-directional switch implementation – review of possibilities
- The current commutation problem
- Practical circuit layout considerations
- Advanced current commutation strategies
- Resonant (soft switching) techniques
- Circuit protection issues

**Modulation Algorithms***- Dr Jon Clare*

- The modulation problem and basic solutions
- Voltage ratio limitation
- Key algorithms with optimized voltage ratio
- Spectral characteristics of converter input and output waveforms
- Filtering requirements
- Practical microprocessor implementation of modulation algorithms

**Summary***- Dr Pat Wheeler and Dr Jon Clare*

- The future and possible exploitation
- Question and answer session

**Intended for**

The tutorial will be of interest to anyone that works in the area of power electronic converters for AC applications and would like to develop a more informed understanding of the matrix converter circuit. These applications include converters for motor drives and static power converters for power conditioning. The tutorial will be aim to address the interests and concerns of both industrial and academic delegates at a time when many are considering the benefits of matrix converter technology for future applications.

**Course
Faculty**

Dr Patrick Wheeler and Dr Jon Clare, University of Nottingham, United Kingdom

**Biography**

*Dr Patrick Wheeler and Dr Jon Clare* are both in the
Power Electronics, Machines and Control (PEMC) group in the
School of Electrical and Electronic Engineering at the University
of Nottingham in England. They both have over ten years
experience in the design, construction and control of matrix
converters through a number of research programmes and have over
14 publications on various aspects of the circuit. The world
class expertise of Dr Patrick Wheeler and Dr Jon Clare in the
area of matrix converter technology has been recognised by a
number of international organisations and they are currently
acting as consultants on matrix converter technology to the U.S.
Army Research Laboratories.

*Dr Patrick W Wheeler* received his PhD degree in
Electrical Engineering for his work on Matrix Converters at the
University of Bristol, England, in 1993. In 1993 he moved to the
University of Nottingham and became a lecturer in May 1996. His
general research interests include novel switching power
converter circuits for AC drives, micro-controllers for drive
applications and the use of switching devices in power
electronics.

*Dr Jon Clare* is a senior lecturer at the University of
Nottingham. He moved to Nottingham from the University of Bristol
in 1990. His general interests are power electronic converters
and systems, control and modelling techniques for power
electronic systems and their associated applications, variable
speed drives and EMC.

T5
: |
Status of the techniques of the
three-phase PWM rectifier systems with low effects on the
mainsby Dr Johann W. Kolar and Dr Hans Ertl |

**Summary**

This practice-oriented course gives an in-depth introduction to all important aspects of the evaluation, analysis and design of three-phase power factor correction (PFC) systems. Starting with a review, classification and analysis of all relevant three-phase converter topologies proposed in the literature during the last decade the basic principle of operation of selected systems will be discussed using phase quantities and space vector calculus. Advantages and drawbacks of single-stage and two-stage isolated AC/DC power conversion will be clarified. Characteristic quantities facilitating the evaluation of various concepts for a given application will be defined. Furthermore, modulation methods, the control oriented behavior, different controller concepts and the controller design for buck-type and boost-type systems will be treated. Also, a simple concept for determining the stresses on the power components will be proposed and the procedure of dimensioning a three-phase PWM rectifier system will be discussed. In connection with this, also the status of different power semiconductor technologies, cooling concepts and packaging techniques will be treated and guidelines for selecting the optimal switch for a different input voltage and power levels will be given. Further important points will be a comparative evaluation of high power telecommunications power supply modules of different manufacturers concerning power density, efficiency and volume and measures for guaranteeing electromagnetic compatibility by differential-mode and common-mode filtering. Finally, the advantages and drawbacks of various simulation tools for application in system design will be discussed and laboratory models of novel PWM rectifier topologies will be shown. Also, alternative concepts like active filters and upcoming developments in the field will be treated.

**Contents**

- Standards and Recommendations Concerning the Limitation of Conducted Harmonic Emissions of Low-Power and High-Power Three-Phase Equipment
- Comprehensive Classification of Known PWM Rectifier Concepts
- Space Vector Calculus
- Basic Principle of Operation of Selected Converter Systems (Direct Three-Phase Systems and Systems Formed by Three-Phase Connection of Single-Phase Converters)
- Single-Stage and Two-Stage Isolated AC/DC Power Conversion
- VIENNA Rectifier
- Comprehensive Evaluation of Known Converter Systems Concerning Complexity, Stresses on the Components, Realization Effort, etc.
- Modulation Methods
- Control Concepts and Control-Oriented Analysis (Small-Signal and Large-Signal Behavior, System Start-Up, etc.)
- Reliability (Two Phase Operation, Over-current Protection)
- Procedure of Dimensioning of the Power Circuit Components (Analytical Calculation Based on Local and Global Averaging)
- Practical Realization (Power Semiconductor Technologies, Passive Components, Materials, etc.)
- Comparative Evaluation of Practical Systems
- Electromagnetic Compatibility (Common-Mode and Differential-Mode Filtering etc.)
- Software Packages for Simulating Stationary and Dynamic System Behavior (Determination of Stresses on the Components, Controller Design etc.)
- Demonstration of Laboratory Prototypes of Novel Single-Stage and Two-Stage PWM Rectifier Systems
- Future Aspects (Active Filters etc.)

**Intended for**

Design Engineers and Design Managers working in the fields of drive technology, process technology (electric welding current sources, inductive heating etc.) and power supply (high power telecommunications power supplies, battery charging, UPS, etc.), engineers concerned with Power Quality of three-phase equipment as well as academics and students preparing for a Ph.D. in the field.

**Course
Faculty**

Dr Johann W. Kolar, TU Vienna, Dept. of Electr. Drives and Machines, and Dr Hans Ertl, TU Vienna, Dept. of Applied Electronics

**Biography**

Johann W. Kolar received the Ph.D. degree (summa cum laude) in Electrical Engineering at the Technical University Vienna where he joined the Dept. of Electrical Drives and Machines in fall 1997. He currently does research in the area of high power factor PWM rectifier systems and control optimization of three-phase inverter topologies for wide speed range AC drives. Also, he is involved as a consultant in numerous industrial research and development projects on AC line conditioning, switched-mode power supplies and inverters. He is the author of 103 technical and scientific papers and patents and is serving as Associate Editor of the IEEE Transactions on Industrial Electronics since 1997.

Hans Ertl received the Dipl.-Ing. (M.S.) degree and the Dr.tech. (Ph.D.) degree in electrical engineering from the Technical University Vienna. Since 1984 he is with the Power Electronics Section of the university and has been working on several industrial research projects in the areas DC and AC drives, power supplies for welding and plasma processes and active rectifier systems. His current research activities are in the field of switched-mode power supplies, class-D power amplifiers and active ripple reduction of power electronic systems. He is the author and co-author of numerous scientific papers and patents.

T6
: |
Design of open inductors and
transformers for power electronics converterby Profs. Tore Undeland and Robert Nilssen and assoc.
Prof. Asle Skjellnes |

**Summary**

The design of Ferrite and METGLAS inductors and transformers will be explained based upon the fundamental physics. A lot of design examples will be discussed and for all these designs measure results will be presented. Since the tutorial is based upon physics and the basic equations, those who follow this course will learn a lot. They will also learn to have a lot of creativity.

We will bring the small inductors and transformers we have designed and made measurements on. We will discuss extensively how to reduce the losses and how to improve the cooling.

**Course
Faculty**

Profs. Tore Undeland and Robert Nilssen and assoc. Prof. Asle Skjellnes, Norwegian University of Science and Technology (NTNU), Faculty of Electrical Engineering and Telecommunications

T7
: |
Drives and electronic parts for
electric vehiclesby Prof. H. Kahlen, Prof. Ferraris, Prof. G. Maggetto,
Dr Hauck and Dr Lamm |

**Abstract**

The important electrical parts of an electric vehicle work together with power electronic and electronic control systems. The tutorial will give an understanding of the drive system and the goals for the necessary power electronic parts for different drives.

Battery charging needs well controlled chargers and good equipments for conductive and inductive connection. The spectrum for the power electronic parts goes from net frequency to high frequencies. EVs with fuel cell systems need a lot of peripheral components which will also content the tutorial.

**Contents**

*Electric vehicle drive systems and their structures*(H. Kahlen)

This part will discuss the drive system consisting of electrical as well mechanical parts: single or multi-motor drives, transmission, hybrid systems, etc...

*Drive Motors*(P. Ferraris)

Different DC and AC motors are used in EVs. Theory and design of standard asynchronous, synchronous and PM synchronous motors will be the content of the course.

*Power electronic converters for electric and hybrid-electric vehicles*(H. Kahlen)

This part will discuss the different power semiconductor available for the design of converter circuits, choppers, inverters, power supply.

*Charger for EV batteries, on-board/off-board, inductive*(G. Maggetto)

Analysis and discussion of different types of charger used practically nowadays on-board the electric vehicles, including conductive and inductive charging systems.

*Electronics and monitoring in EVs*(B. Hauck)

This parts emphasizes the small signal electronics used in the electric vehicle: microprocessor, bus systems, memories, etc... to monitor and communicate.

- PEM fuel-cell systems for mobile applications (A. Lamm)

A fuel-cell system is more than an electrochemical power source like a battery. The system needs a lot of peripheral parts.

**Intended for**

Powerelectronics and drives people with interst for the future of electric and hybrid vehicles.

**Course
Faculty**

Prof. Hans Kahlen, University of Kaiserslautern,

Prof. Paolo Ferraris, Politecnico di Torino,

Prof. Gaston Maggetto, Vrije Universiteit Brussel,

Dr Bernhard Hauck, University of Kaiserslautern,

Dr Arnold Lamm, DaimlerChrysler Ulm

T8
: |
Low power and low voltage power
suppliesby assoc. Prof. José A. Cobos and Prof.
Javier Uceda |

**Summary **

This seminar covers design issues on Voltage Regulator Modules (VRM), which are advanced power supplies to feed the new low voltage and low power integrated circuits. The main requirements are high efficiency, small size and fast dynamic response.

New techniques are proposed to reduce losses and increase power density in these low output voltage DC/DC converters, which are based on the use of synchronous rectification. The new schemes to perform this task are very sensitive to the coupling of the power transformer. Design guidelines to optimize these components and an assessment on the most appropriate technologies are also described in detail.

The seminar covers the whole design cycle, providing guidelines to select the optimum topology for a given specification. Finally these guidelines are applied to the design of an actual demonstrators that supplies efficiently 1.5V for Telecom applications.

**Contents **

Concepts on Low Power and Low Voltage

- Low power demands low supply voltage
- State of the art in low voltage power converters

New specs and goals of VRM (Voltage Regulator Module)

- Size
- Efficiency
- Dynamic Regulation

Key issues to meet specifications

- Influence of the topology
- Synchronous Rectification (low voltage)
- Transformer Coupling
- New technologies

Analysis of most suitable topologies

- Resonant topologies
- Forward topologies
- Half Bridge topologies
- Pre-regulator + optimized stage for SDSR
- Interleaving techniques
- Comparison of more suitable topologies

Demonstration and assessment of actual results

- Design issues
- Transformer design and test
- Packaging and actual implementation
- Actual measurements
- Summary

**Intended for**

The seminar is useful to a broad range of designers, ranging from novel to experienced engineers in the field of power electronics, who will need to design power supplies for the coming low power integrated circuits.

**Course
Faculty**

José A. Cobos and Javier Uceda, Universidad Politécnica de Madrid (UPM), Spain

**Biography**

Javier Uceda: Doctoral degrees from Universidad Politécnica de Madrid (UPM) in 1979.

From 1976 to 1981 he was Assistant Professor at Universidad Politécnica de Madrid. In 1982 he became Professor at Universidad de Oviedo. Since 1986, he is Professor at Universidad Politécnica de Madrid.

His research interests include high-frequency and high-density power converters, high power factor rectifiers and modeling of magnetic components. He is co-author of more than 100 technical papers in IEEE conferences and publications.

He is member of the Editorial Board of the European Power Electronics and Drives (EPE) Journal and of the Steering Committee of the EPE Association. He is member of the Adcoms of both IEEE Power Electronics and Industrial Electronics Societies.

José A. Cobos: Doctoral degrees in Electrical Engineering from Universidad Politécnica de Madrid in 1994. He joined the División de Ingeniería Electrónica of this university in 1987, where he is Associate Professor since 1996.

He is member of the IEEE since 1992, where he has contributed in different activities. He published more than 75 papers in International conferences and journals, most of them from the IEEE. He is Member of the Program Committee of various International conferences (PESC, APEC, INTELEC, PEDES, CIEP and EPE).

He is involved in many European research projects dealing with most topics related with high frequency power supplies. His main interests are distributed power supplies, on board converters, power factor correction, and modeling of systems and magnetic components.

T9
: |
Sensorless control of induction
motors and permanent magnet synchronous motorsby Prof. Dr Manfred
Schrödl |

**Summary**

The tutorial shows methods of speed-sensorless control of induction machines and permanent magnet synchronous machines (PMSMs, EC motors, Brushless DC motors, respectively). The presented methods offer the possibility of a relatively simple implementation in industrial drives and hence, methods with high mathematical expense will only be mentioned briefly. EMF-based models for high speed as well as saturation-based and reluctance-based models for low speed and standstill will be discussed.

The author shows practical examples of realized drives. A practical demonstration example of a sensorless PSMS drive with high starting torque will be presented. Possible fields of applications for sensorless drives will be discussed.

**Contents**

**Introduction (15’)**

- Goals of the tutorial. Why « Sensorless Control » ?
- Discussing motivation of tutorial participants for attending the tutorial.

**Basic inverter structure for sensorless IM and PM drives (30’)**

- Structure with phase current measurement.
- Structure with DC link current measurement.

**General mathematical description of AC machines (45’)**

- Per unit quantities
- Definition of space phasors for voltages, currents, flux linkages
- Calculating a phase quantity from a space phasor quantity
- Voltage equation of a coil
- Voltage space phasor equation of AC stator winding system
- General flux linkage equation of stator winding
- Torque production based on stator current and stator flux linkage

**The permanent Magnet Synchronous Motor – Modelling, Control (30’)**

General description

- Mathematical description by means of space phasors
- Flux linkage equation of PMSM
- Torque production of PMSM

Control methods

- PMSM control with 60°-current blocks (BLDC-mode)
- PMSM control with sinusoidal currents

**Sensorless rotor position detection of the PMSM (60’)**

Sensorless position detection at high speed

- Quasi-continuous detection for sinusoidal commutation

- Calculating rotor position using the voltage mode
- Calculating rotor position using inverter short circuit state

- Detecting commutation information for BLDCV mode

- Back EMF evaluation in the passive phase BLDC mode

Position detection at low speed and standstill (INFORM method) (INFORM : Indirect Flux detection by On-line Reactance Measurement)

- The complex differential inductance
- Reaction of the current due to a voltage step
- Calculating double the value of rotor angular position
- Initializing the INFORM model by shifting the magnetical set point
- Examples of INFORML-measured rotor positions of some PMSMs

Improving the estimated rotor position and developing estimated speed

- Simple state model of the machine (speed, position, load torque)
- Measurement error feedback to improve estimated state
- Examples of PMSMs with state estimator

**The induction motor – modelling and control (30’)**

General description

- Mathematical description by using space phasors
- Flux linkage equations of IM
- Torque production of IM

Control methods

- U/f-control for low dynamic properties
- Field-oriented control (example for highly-dynamic operation)

**Sensorless rotor flux angular position detection of the IM (60’)**

Sensorless position detection at high speed

- Voltage model for high speed operation
- Current model for arbitrary speed (needs mechanical sensor)
- Model using inverter short circuit state

Sensorless flux detection at low speed

- Sensorlesss control down to flux standstill (INFORM method)
- Reaction of the current due to a voltage step
- Calculating double the value of rotor flux angular position
- Initializing the INFORM model by magnetizing the IM
- Examples of INFORM-measured rotor flux position in real drives

Improving the estimated rotor flux position

- Simple state model of the machine
- Measurement error feedback to improve estimated state
- Examples of Ims with state estimator

**Practical example (Demonstration) (30’)**

- INFORM-controlled sensorless PM drive with high starting torque
- Discussion on the properties of the drive and possible applications

**Systematic selection of appropriate sensorless control schemes (20’)**

- Developing a list of practical applications for sensorless control
- Table with technical and economic criteria for selecting appropriate drive

**Discussion**

**Intended for**

R&D engineers in the field of speed-variable electric drives (e.g. automotive, traction, pumps and fans, elevators, chemical and machinery industry); Diploma and doctoral students of Electric Engineering ; Project managers of industrial and scientific drive projects.

**Course
faculty**

Prof. Dr. Manfred Schrödl, Technical University of Vienna, Austria

**Biography**

Prof. Manfred Schrödl achieved his Dipl.Ing. (1982), Dr. (1987) and habilitation degree (1992) at TU Vienna. Between 1992 and 1996 he was head of the development department of ELIN Vienna. From 1996 to 1998 he was head of the central technical division of ATB Austrai Antriebstechnik, Spielberg (Styria, Austria). Since February 1998, he is head of the Institute of Electrical Drives and Machines at Vienna University of Technology. He has about 50 publications and 10 patents mainly in the field of Electrical Drives. His actual main research field is Sensorless Control of AC Machines.

Mail to Local Organisation Committee: epe99@epfl.ch

Copyright © 1998, EPFL. All rights reserved.

Last update: Thursday, 03-Jun-99 14:46:13 MET DST