University
of Utah
Department
of Electrical and
Computer Engineering
ECE 5570
Control of Electric Motors
Fall 2010
Instructor: Professor Marc Bodson
Office: MEB 3268, Tel.: 581-8590
E-mail: bodson@eng.utah.edu
Class: MWF 2:00PM-2:50PM, WEB 1460
Class web page: http://www.ece.utah.edu/~ece5570/
Lab web page: http://www.ece.utah.edu/nsf_5570
1. Introduction
Electric
actuators are at the core of many industrial applications, including
manufacturing, process control, and transportation. New developments in
power
electronics and computing technology have made it possible to control a
variety
of motors, including AC motors, and to achieve fast and precise
tracking.
Advanced features of computer-controlled systems, such as adaptation
and
efficiency optimization are also becoming increasingly common.
2. Course
Objectives
The
objectives
of the course are to:
·
provide
an understanding of the
operation of the motors, of their state-space models, and of the use of
these
models for simulations and for control system design.
·
give
a working knowledge of
methods used for the control of DC and AC motors, including open-loop
and
closed-loop methods and the selection of the controller parameters.
3. Course
Contents
Introduction
to electric motors: Basics of electromagnetic energy
conversion and derivation of electric motor models. Linear and
switching
amplifiers, pulse-width modulation. Power electronic devices,
topologies of
electrical drives, and quadrants of operation. Optical encoders,
resolvers, and
other position sensors.
Control of brush DC motors: Construction and operation of brush DC motors. Model of a permanent-magnet brush DC motor. Steady-state characteristics and torque limits. Dynamic response under voltage and current command. PID control laws for speed and position regulation. Switching and time-optimal control algorithms. Separately excited, shunt, and series DC motors. Field weakening.
Control
of synchronous motors: Construction
and operation of synchronous motors. Model of a two-phase
permanent-magnet
synchronous motor. Static and dynamic characteristics. Open-loop
control,
stepping and microstepping. Closed-loop quadrature control. DQ
transformation
and DQ model. Closed-loop control in the DQ frame of reference. Torque
optimization and field weakening. Hybrid stepper motors and reluctance
motors.
Control
of induction motors: Construction
and operation of induction motors. Model of a two-phase induction
motor.
Steady-state characteristics, equivalent circuit, and torque curves
under
voltage and current commands. Open-loop control with constant V/f.
Closed-loop
slip control. Models in rotating frames of reference. DQ transformation
for
induction motors and field-oriented control.
Brushless
DC motors: Construction,
modeling, and characteristics of three-phase permanent magnet
synchronous
motors. Sinusoidal commutation and quadrature control. Six-step
commutation.
Three-phase
motors: Three-phase
supplies and connections. Three-phase to two-phase transformation.
Unitary
transformations and three-phase DQ transformation. Model of a
three-phase
synchronous motor and equivalent two-phase motor model. Control of
three-phase
synchronous motors using the DQ transformation. Three-phase induction
motors:
modeling and two-phase equivalent motor.
4. Prerequisites
A
basic course
on control system design (ECE 3510, ME EN 5200/6200, CH EN 4203, or
equivalent)
is required. A course on state-space analysis (ME EN 5210/6210, CH EN
5203, or
equivalent) is recommended but not required.
5. Textbook
Course
notes are
available for purchase at the University’s bookstore.
6. Office hours
Fixed
office hours are not scheduled for
this class. The instructor will be available for questions after class,
and
individual appointments will be made upon request after class or
through email.
Drop-in’s at the instructor’s office are acceptable, but
will only be
accommodated as circumstances permit.
7. Grading
Grades
will be
based on homeworks, labs, and a final project. There will be no exams.
Homeworks will consist in exercises and in computer simulations. The
simulations will implement nonlinear models of electric motors to
analyze their
responses and to design control systems. Laboratory experiments will
complement
the homeworks by providing practical experience with the control of DC
motors,
stepper motors, induction motors, and brushless DC motors. The final
project is
described in next section.
Students
should respect the due dates listed on the assignments. Reports may be
turned
in within a three-day grace period at no penalty (for example, homework
due on
Friday may be returned up to Monday at 5pm). Between three days and a
week
after the due date, 80% of the earned grade will be given. Work will
not be accepted
beyond a week without approval of the instructor.
8. Final Project
Completion of a project is required for the class. A project consists in an independent investigation of a topic of current interest related to the course. Students are responsible for the selection of the topic of their project, and may consider subjects that are related to their own research. However, the topic must approved by the instructor. The timetable is the following:
Oct. 8: Submit a project description with references (1 page).
Nov. 12: Submit a partial report with the results obtained until then (5 pages).
Dec. 10: Submit a final report (15-30 pages + appendix).
A typical project consists in a survey of at least 3 papers from the research literature, organized around a common topic. The most convenient source is the IEEE Xplore database freely available to users of the University of Utah’s network (www.ieeexplore.ieee.org). Examples of journals with contributions in the field of electric motor control are the IEEE Trans. on Industry Applications, the IEEE Trans. on Industrial Electronics, and the IEEE Trans. on Control Systems Technology. Other publications available from the university’s library system may also be consulted, and web search engines such as Google can be useful. Copies of the papers used for a project must be attached in the appendix of the report.
The criteria for the grading of the reports will be:
(a) originality and critical thinking
(b) technical accuracy
(c) scope of the work
(d)
quality of
presentation (logical organization, clarity and neatness of the report).
Copying from papers (or simply paraphrasing) will not be considered a valid contribution. Students are expected to write the report in their own words and to demonstrate that they have read the papers, understood them, and thought about them in a critical and investigative manner. Examples of contributions include: critical evaluation of the significance of the results, comparison of different approaches, independent verification of the results (e.g., through simulations), and simplified or expanded analysis of the results. A project may be approved with a small number of papers if extensive validation of a concept in simulations or in experiments is proposed.
Examples of topics include:
· Control of doubly-fed induction motors or generators
· Control of synchronous generators with field winding
· Split-phase induction motors or generators
· Rotor time constant estimation for induction motors
· Variable structure control & direct torque control
· Real-time parameter estimation for electric machines