ECEN 5737

Adjustable Speed AC Drives

ECEN 4167

Energy Conversions 2

 

Spring 2015

 

Last revised

7/6/2014

 

Instructor

 

Harry H Hilgers

harry.hilgers@colorado.edu

Office: OT 352

 

Course Objectives

 

·         The study and simulation of torque and speed control of symmetrical 3-phase electric induction and permanent magnet synchronous machine drives.

o   The core tools for the study are the underlying physics, magnetic and electrical circuit equations of electric machines.

o   The necessary reference frame theory will be done using space vectors described with complex mathematics.

http://www.ece.umn.edu/users/riaz/animations/spacevecmovie.html

o   Simulation will be a major part of the course and will be done using Matlab/Simulink.

 

Pre-requisites

 

By Courses (CU Boulder)

 

·         Intro-to-Circuits and Circuits-as-Systems (or the traditional Circuits 1 and 2)

o   ECEN 2250 and ECEN 2260

·         Energy Conversion 1

o   ECEN 3170 (this includes basic usage of Matlab and Simulink)

·         Highly recommended but not required: Linear systems and control systems

o   ECEN 3300

o   ECEN 4138

 

By Topics

 

·         Basic usage of  Matlab and Simulink

·         General Physics of Electricity and Magnetism

·         Undergrad Differential Equations and Linear Algebra

·         Fundament circuits in the time and frequency domain

·         The application of Laplace Transforms for solving of electric circuits

·         Fundamental Electronics

·         Complex Algebra, Euler’s identity (extremely  important)

·         Fundamental block diagrams

·         Phasors

·         Real and reactive power in single phase circuits, power triangle

·         Balanced three-phase circuits, wye and delta connections

·         Fundamental magnetic circuits

·         Transformers (single and three-phase) and their equivalent circuits

·         AC-machinery fundamentals, forces/torques of electric machines

·         Per-unit method

·         Synchronous machines from a magnetic field point of view (equivalent circuit, phasor diagram, stability)

·         Synchronous motors (starting, damper windings, stability)

·         Three-phase induction machines (equivalent circuit, quasi-steady state torque-speed curves derived from a magnetic field point of view and from the equivalent circuit point of view, NEMA A, B, C, D designs, starting in-rush, traditional speed control methods)

·         DC machinery fundamentals (internal generated voltage and torque, commutation, DC motors (separately and series excited) and their block diagrams.

 

Pre-Requisite Review Sources

 

·         Text books:

o   Electric Machinery

§  Chapman, Electric Machinery Fundamentals (used in ECEN 3170)

§  Fitzgerald, Kingsley, Umans, Electric Machinery

§  Sen, Principles of Electric Machines and Power Electronics

o   Electric Circuits

§  The analysis and design of Linear Circuits, Thomas/Rosa/Toussaint

§  Most any undergrad circuits text

o   Linear Systems and Controls

§  Most any undergrad linear systems and controls text.

·         Student version of Matlab/Simulink R2013a.

 

 

Course Syllabus

 

·         Short review of 3-phase voltages, magnetic circuits and transformers.

·         Short review of basic mechanics.

·         Simulink simulation example of the acceleration of a small car.

·         Torque-speed curves of typical mechanical loads.

·         Basic structure, analysis and modeling of electric machines.

o   DC machines

o   Synchronous machines

 

o   Induction machines

·         The number one advantage of DC machines:

o   The angle between field flux vector and armature current flux vector is always at 90 degrees.

o   Therefore this angle does not require any special control of these vectors to keep it there.

·         The number one drawback of using DC machines for EV drives

o   Commutator and brushes are relative high maintenance.

·         The number one advantage of induction machines and PM synchronous machines:

o   Relative low maintenance.

·         The number one drawback of induction motors and PM synchronous machines:

o   The angle between field flux vector and armature current flux vector is not always at 90 degrees.

o   Therefore this angle requires relative complicated control of these vectors to keep it there.

§  This is referred to as “vector control”.

·         How vector control of AC machines mimics DC machine controls

·         Reference frame transformation using space vectors in an arbitrary reference frame

o   COMPLEX space vector d-q transformation.

§  All d-q transformations will all be done using complex analysis

§  Matrix d-q modeling will only be mentioned in passing.

o   Matlab and Simulink modeling of unified complex space vector transformations from any frame to any other frame (abc, arbitrary, stator, rotor, synchronous reference frames)

·         d-q modeling of induction machines based on complex space vectors

o   Derive 3-phase electrical equations of motion.

o   Convert these equations to/from any arbitrary d-q reference frame

o   Derive torques expressions in arbitrary reference frame

o   Simulation of these equations in Simulink model using d-q coordinates and their different transformations.

·         d-q modeling of synchronous machines based on complex space vectors

o   Derive 3-phase electrical equations of motion.

o   Convert these equations to/from any arbitrary d-q reference frame

o   Derive torques expressions in arbitrary reference frame

o   Simulation of these equations in Simulink model using d-q coordinates and their different transformations.

·          Regulator design

o   Current regulator

o   Speed regulator

o   Voltage regulation

o   Simulink simulation of the regulators

·         Closed loop vector control of induction and permanent magnet synchronous machines

o   Instantaneous torque control

§  DC machine

§  Surface-mounted and interior-mounted permanent magnet synchronous machine

o   Vector control of an induction machine

§  Direct vector control

§  Indirect vector control

o   Rotor flux linkage estimator

§  Voltage model

§  Current model

§  Hybrid model

§  Enhanced hybrid model

o   Flux weakening control

§  Voltage and current constraints

§  Permanent magnet AC machine operating region in current plane and rotor ref. frame

§  Flux weakening control of a PM synchronous machine

§  Flux weakening of an induction machine

·         (If time permits) Sensorless Speed control

 

Text Books

·         Text books:

o   Required

§  Control of Electric Machine Drive Systems, Seung-Ki Sul, Wiley, IEEE Press

·         You will get an extensive errata file.

·         During lecture, this text book will be supplemented by several hundred PowerPoint charts.

o   Required software

§  Access to Matlab/Simulink

o   Highly recommended but not required

·         Sensorless vector and direct torque control, Peter Vas, Oxford Science

·         Student version of Matlab/Simulink R2011 or later.

 

IDEATE

http://mocha-java.uccs.edu/ideate/courses.html#ECEN5737