40042 - Electric Drives for industrial and Wind Energy Applications

Learning outcomes

At the end of the course, the student knows: - the general methodologies to understand the performance and control of electrical machines and drives - the fundamentals of the electrical machines, from circuit behavior to electromagnetic torque production, and the basic equations of the physical phenomena - the mathematical models of electrical machines, which are valid for steady-state and transient analysis - how to model and simulate dc motor drives, permanent magnet brushless motor drives, induction motor drives, and stepper motors. Also, the course focuses on the fundamentals of electric generators and drives for wind energy systems, which are used as examples of applications.

Course contents

The course is designed for students of degree programs in Electrical Energy Engineering and aims to provide the fundamental tools to comprehend the structure and functionality of the primary electrical drives and their control systems, as well as to define the principles of electromechanical energy conversion.
The initial section of the course examines the structure and characteristics of the principal electric machines. The subsequent section incorporates laboratory exercises in which the drives observed in the theoretical segment are implemented. To integrate the theoretical lessons, authentic catalogues and practical applications will be examined. The final section of the course is devoted to the analysis of vector controls of electric machines.

Introduction

This section provides an overview of the fundamental concepts related to electrical machines and drives. It also includes a brief review of the principles of electrical engineering, as well as an introduction to the properties of magnetic and conductive materials.
Magnetic Circuits
This section introduces the fundamental concepts of magnetic circuits and the principles of electromechanical energy conversion. It also covers the basics of heat rejection in electric machines and the use of space vectors and phasors.

 

Drives for DC machines


Introduction to the principles of electromechanical energy conversion, magnetic circuits and thermal problems of electric machines.


DC machine
Machine geometry and operating principle.
Expression of torque, equivalent electrical circuit and mechanical characteristic.
Engine and generator operation. Torque and speed control principle.
Field weakening and constant torque and power operating zones.
Drives for DC machines

 

Drives for three-phase synchronous machines and sinusoidal emf brushless motor


Machine geometry and operating principle.
The rotating magnetic field.
Expression of torque, equivalent electrical circuit and mechanical characteristic.
motor and generator operation.
Dynamic model of synchronous machines based on the theory of quadrature axes.
Field oriented control. Limit performance analysis in torque and speed

 

Drives for BLDC


Construction characteristics and operating principle.
Phase power supply sequence as a function of the rotor position.
Six-step operation with two phases powered at a time.
Switching transients and torque oscillations.
Block diagram of the drive

Drives for three-phase asynchronous machines


Machine geometry and operating principle.

Expression of torque, equivalent electrical circuit and mechanical characteristic.

Engine and generator operation.
Starting problems.
V/f control.
Operating range at constant torque and constant power.
Dynamic model of asynchronous machines based on the theory of quadrature axes.
Field-oriented control of asynchronous motors.
Methodologies for direct and indirect torque control.
Rotor flux estimation.
Limit performances in torque and speed of drives with asynchronous motors


Single-phase asynchronous motors


Structure and operating principle
Capacitor start
Capacitor start and run
Shaded pole

 

Drives with stepper motors

Machine geometry and operating principle.
Simplified dynamic model.
Power circuits and control techniques.
Analysis of low and high speed instability problems.
Analysis of torque limit performance as the power frequency varies.

 

Drives for the generation of energy from wind sources

State of the art technology.
The Italian case.
Turbine types.
MPPT algorithms.
Drives for wind energy conversion systems.

Readings/Bibliography

The course presents and summarizes various topics and therefore handouts written directly by the teacher and made available through the virtual.unibo.it platform will be distributed to the student.


The following reference texts are also reported:


A.E. Fitzgerald, C. Kingsley JR, A. Kusko: “Macchine Elettriche”, Franco Angeli Editore, Milan, 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 classroom lessons are integrated with computer exercises and the use of experimental setups provided by the instructor in the laboratory. During the exercises, students will be able to simulate and implement the behavior of electric machines and control systems in a tangible manner, thereby reinforcing the concepts learned in the course.


The simulations will be made available to students via the portal.

Assessment methods

The acquisition of knowledge is evaluated through a written examination, which is designed to assess the extent to which the program's objectives have been met. Furthermore, an optional oral examination may be taken. The final grade will be determined by averaging the scores of the written test and any oral test.


The written examination may include multiple-choice questions, open-ended questions, and numerical exercises. The student must demonstrate the ability to:




The final evaluation will consider the correctness, expository ability, and ownership of language in presenting the answers to the questions.

Teaching tools

The lessons are carried out with the aid of a PC and video projector (Power Point). PDF files of the slides shown during the course are available.

Office hours

See the website of Michele Mengoni