Matrix Converters
Professor Jon Clare and Professor Patrick Wheeler,
University of Nottingham, UK

Synopsis

This tutorial aims to provide an introduction to matrix converters for those who have not studied them in detail before. The basic concept is introduced and the key issues of control (modulation) and practical realisation (commutation) are covered. There is also a brief discussion of so-called "sparse", or 2-stage matrix converters. Finally application issues are discussed with reference to various prototypes built by the team at Nottingham.

Biographies

Jon Clare and Pat Wheeler are both with the Power Electronics, Machines and Control Group at The University of Nottingham. They have worked together on matrix converters for the last 15 years and have published over 120 papers on the subject. Their Group is renowned internationally for its work on matrix converters and particularly for work on practical and application issues.

They have collaborative research programmes on matrix converters with a wide range of industries and have developed a number of "World first" technology demonstrators, including the highest power matrix converters reported to date.

Sensorless Motor Drives
Professor Ralph Kennel, University of Wuppertal, Germany

Synopsis

In many industrial applications resolvers are used as position feedback sensors for electrical drives. As a resolver is nothing else than an electrical AC machine of special design, there is the basic idea to operate the servo motor itself like a resolver – in parallel to its original drive operation, of course.

High frequency resolver signals are injected to the servo motor without disturbing its original purpose (ie. the production of torque). The reaction of the servo motor on the high frequency signals can be detected by the current sensors, which are available with respect to the current control loop anyway.

A lot of schemes and concepts for encoderless AC drive control providing good operation during standstill are already published. Acceptance by industry, however, is not very extended. The main reasons for hesitations in industry are

• additional processing performance being necessary for the controller or signal processor
• additional sensors or hardware
• parameters to be adjusted for encoderless control

The concept for encoderless control presented in this tutorial has no restrictions with respect to a minimal speed or frequency. Furthermore it is possible to implement it in industrial servo drives without additional hardware requirements and without need for parameter adjustments.

Biography

Ralph M. Kennel got his Dr-Ing (PhD) degree 1984 from the University of Kaiserslautern.

From 1983 to 1999, he worked on several positions with Robert BOSCH GmbH (Germany). Until 1997 he was responsible for the development of servo drives. Between 1997 and 1999 Dr Kennel was responsible for "Advanced and Product Development of Fractional Horsepower Motors" in automotive applications.

From 1994 to 1999, Dr Kennel was appointed Visiting Professor at the University of Newcastle-upon-Tyne (UK). Since 1999 he is Professor for Electrical Machines and Drives at Wuppertal University (Germany).

Dr Kennel is a Senior Member of IEEE, a Fellow of IEE and a Chartered Engineer in the UK.

Multi-Phase Induction Machines
Professor Sandy Smith and Professor Steve Williamson, University of Manchester, UK

Synopsis

This tutorial session will focus on the use of multi-phase windings for induction machine drives. For many decades standard industrial induction motors and generators have been line-fed three-phase machines.

There is now a growing trend for variable-speed induction drives using variable-voltage, variable-frequency converters to supply the motor. In the early days, these converters produced a three-phase variable-frequency supply but there is no technical reason why the output phase number cannot be increased. This has stimulated a lot of industrial interest in multi-phase induction machines and this tutorial will look at the benefits of multi-phase operation.

Topics will include: induction motor models to examine the various complex harmonic interactions, efficiency improvements and fault tolerance including possible post-fault control strategies.

Biography - Professor Sandy Smith

Academic appointments include Imperial College (1984-1990), and Cambridge University(1990-97). In 1997 joined Invensys Brook Crompton as Head of Research responsible for advanced motor technology. In 2000 joined UMIST as a Senior Lecturer; Reader in Electrical Machines in 2003 and Professor of Electrical Machines in 2007.

Past chairman of the IEE Professional Group PG1 (Electrical Machines) (1997-2000) and chairman of the Executive Board of the IEE Professional Network ‘Power Conversion and Applications (2000-2003). Appointed Director in 2003 of the Rolls-Royce University Technology Centre at Manchester on ‘Electrical Systems for Extreme Environments’.

Research interests in the area of design and modelling of motors, generators and drives.

Fault Tolerant Drives
Dr Dave Atkinson, Professor Barrie Mecrow and Dr Volker Pickert, University of Newcastle upon Tyne, UK

Synopsis

This tutorial covers the basic ideas used in fault tolerant drives and reviews some of the current research in this area. The relative merits of SRM and PM are covered and various fault tolerant converter circuits are described. A number of fault tolerant drive application examples are then covered in detail.

Biography - Dr Dave Atkinson

Dr Atkinson is a Senior Lecturer and belongs to the Power Electronics, Drives and Machine research group at Newcastle University. He joined the group in 1987 after 17 years in the electronics industry including period at NEI Electronics and British gas Corporation.

His technical interests include variable speed drives, fault tolerant drives, power electronics and control for renewable energy systems.

Dr Atkinson is a member of the IET and a Chartered Engineer.