37064 - Electrical Drives T

Learning outcomes

At the end of the course, the student knows: - the most common electric drives and the problems related to their use in industrial automation applications - the operating characteristics and the performance of electric drives that use DC machines, brushless DC and AC motors, induction machines, stepper motors and direct type actuators, powered by electronic power converters - the steady-state and dynamic models of electric machines. In addition, the student is able to understand the operation of torque and speed control schemes for electric drives, as well as the principles for sizing and selecting the most suitable electric motor in specific applications.

Course contents

The course is intended for students of Automation Engineering and aims to provide the fundamental tools to understand the structure and operation of the main electrical machines, as well as to define the basic concepts of electromechanical energy conversion and electrical drives.

The first section of the course focuses on the study of the operating principles of electronic converters commonly used in industry. The second section analyzes the structure and characteristics of the most important electrical machines. Finally, the last section of the course is dedicated to examining vector controls applied to electrical machines.

Introduction

- Overview of electrical machines and drives.
- Fundamental concepts of electrical engineering.
- Magnetic materials and conductors.
- Magnetic circuits.
- Principles of electromechanical energy conversion.
- Thermal dissipation in electrical machines.

Static Conversion of Electrical Energy

- Introduction to the physics of semiconductor materials.
- Power electronic devices for static conversion: diodes, MOSFETs, IGBTs.
- AC/DC converters, both controlled and uncontrolled, single-phase and three-phase.
- Buck-type DC/DC converters.
- DC/AC converters, both single-phase and three-phase.

Electromechanical Energy Conversion

- Principles of electromechanical energy conversion, magnetic circuits, and thermal management of electrical machines.
- DC machines: structure and operating principle, torque, equivalent circuit, and mechanical characteristics.
- Three-phase synchronous machines: structure and operating principle, rotating magnetic field, torque, equivalent circuit, and mechanical characteristics.
- Asynchronous machines: structure and operating principle, torque, equivalent circuit, and mechanical characteristics.
- Dynamic model of synchronous and asynchronous machines (Clarke and Park transformations).

Drives and Control Schemes

- Drives with DC machines.
- Drives with synchronous machines.
- Drives with brushless machines with trapezoidal back EMF.
- Scalar drives for asynchronous machines.
- Vector drives for asynchronous machines.
- Drives with stepper motors.

Readings/Bibliography

• A.E. Fitzgerald, C. Kingsley JR, A. Kusko: “Macchine Elettriche”, Franco Angeli Editore, Milano, 1978.
• J.M.D. Murphy, F.G. Turnbull: “Power Electronic Control of AC Motors”, Pergamon Press, Oxford, 1988.
• I, Boldea, S.A. Nasar: “Electric Drives”, CRC Press, New York.
• P. Vas: “Vector Control of AC Machines”, Oxford University Press, New York.
• T.J.E. Miller: “Brushless Permanent-Magnet and Reluctance Motor Drives”, Clarendon Press, Oxford, 1989.
• T.J.E. Miller: “Switched Reluctance Motors and their Control”, Clarendon Press, Oxford, 1993.
• T. Kenjo: “Stepping Motors and their Microprocessor Controls”, Clarendon Press, Oxford, 1985.
• W. Leonard: “Control of Electrical Drives”, Springer-Verlag, Berlin, 2001

Teaching methods

The lectures are integrated with computer-based exercises (MATLAB-Simulink) conducted in the classroom.

Assessment methods

The assessment of learning is conducted through a written exam, which aims to evaluate the acquisition of the knowledge outlined in the program. Additionally, an optional oral exam may be taken. The final grade results from the average of the written exam score and the optional oral exam score.

The written exam may include multiple-choice questions, open-ended questions, and numerical exercises. The final evaluation will consider the correctness, the clarity of exposition, and the appropriateness of language used in presenting the answers to the questions.

Teaching tools

The lectures are conducted using a PC and a video projector (PowerPoint). PDF files of the slides presented during the course are available.

Office hours

See the website of Luca Zarri