28553 - Electric Drives

Learning outcomes

At the end of the course, the student gains insights into the performance of the main electric drives through the analysis of the most common electric machines, power converters and industrial applications. In particular, the student can •model DC machines, synchronous machines and induction machines, •simulate the corresponding electric drives in Matlab/Simulink environment, •understand the closed-loop control schemes for the regulation of torque, speed and position of electric actuators and machines used in industrial applications.

Course contents

The course 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

Students will receive course notes prepared by the lecturers, which will be made available through the Virtuale platform.

The following textbooks are recommended as reference materials:

• 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 complemented by numerical exercises, computer-based modeling using MATLAB/Simulink, and the use of multimedia teaching materials.

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.

 

Students with specific learning disorders (SLD) or temporary/permanent disabilities

We recommend contacting the University Office responsible for support services in a timely manner (https://site.unibo.it/studenti-con-disabilita-e-dsa/en). The office will evaluate the students' needs and, where appropriate, propose possible accommodations. These must in any case be submitted for approval at least 15 days in advance to the course instructor, who will assess their suitability also in relation to the learning objectives of the course.

Teaching tools

Lectures and practical exercises are delivered with the aid of a computer and a projector. PDF versions of the PowerPoint slides presented during the course, MATLAB/Simulink models, multimedia teaching materials, and numerical exercises are made available through the Virtuale platform.

Office hours

See the website of Luca Zarri

See the website of Luca Vancini