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CONCORDIA UNIVERSITY
Department of Electrical and Computer Engineering
ELEC 6411 – Power Electronics I
Course Outline
Fall 2015
Course Instructor: Dr. Luiz A. C. Lopes
Office: Concordia University
Telephone: 848-2424 ext. 3080
E-mail: [email protected]
Office Hours: Thursday, 15:30 – 17:00 hs.
Course Web site: https://www.moodle.concordia.ca
Textbook: N. Mohan, T.M. Undeland, and W.P. Robbins, Power Electronics:
Converters, Applications, and Design, Media Enhanced Third Edition,
John Wiley & Sons, Inc., 2003, ISBN 0-471-22693-9
Alternate Text: M.H. Rashid, Power Electronics: Converters, Devices and Applications,
Prentice Hall, 1993, ISBN 0-13-678996-X
Course Outline: Objectives of the course
The course presents the operating principles of static power converters
commonly used in practical industrial systems. It addresses the underlying
concepts and methods behind various applications ranging from low-
medium power utility interfaces to high power transmission systems. A
special emphasis will be placed on renewable and alternate energy systems
applications and power transmission and distribution system
compensation and enhancement.
By the end of the course, the student is expected to:
• Understand the operating principles of static power converters and
aspects of their application in electrical power systems.
• Be able to define the analytical expressions related to the operation of
static power converters and to evaluate/compare the electrical
performance of various options and topologies.
• Be able to carry on the basic analysis and specification of static power
converters for specific applications.
• Be able to carry on simulation studies of a power electronic system.
Lecture : Monday, 14:45 – 17:30, SGW H-407
ELEC-6411 Power Electronics I Lopes, Luiz A.C. Course Outline – Fall 2015
Page 2 of 3
Project: Teams of up to four students. Focus on the analytical study, ideally
including a design, and simulation and discussion of a
converter/application chosen by the students.
Content:
1) Power conversion context: Role of the equipment and design specifications. 2) Discussion of possible power converter configurations and modulation techniques and reason for your choice 3) Basic design: Power switches, passive components and modulation technique 4) Simulation of the converter with PSIM or MATLAB (H-921) 5) Analysis of simulation results to check if the design specifications are met and to validate the design procedure 6) Final remarks and conclusions
Assignments: Assignments will be handed out every other week and are due in a week.
Late assignments may be turned in but are subject to a penalty of 10 points
per day. Assignments are not received after the solutions are posted.
Marker: Mrs. Nazli Kalantari [email protected]
Grading Scheme: Assignments 10 %
Project report 20 %
Mid-term exam 25 %
Final exam 45 %
Total 100 %
Note: The final exam is scheduled by the examinations office, not by the
instructor.
Marking: Partial marks are assigned by the instructor. Students must present sound arguments when questioning marks. Bringing up non-technical and personal arguments is highly unethical and unprofessional. There is no supplementary work and no “HELP” can be provided after the letter grades are entered.
Academic conduct: Academic dishonesty is not acceptable. It will be documented and punished as per Concordia University regulations. Please do not ruin
your career.
Professionalism: Employers expect our graduates to behave like professionals.
- A professional is reliable – gets the job done on time.
- A professional has initiative – finds out what he/she does not know.
- A professional is respectful to others.
ELEC-6411 Power Electronics I Lopes, Luiz A.C. Course Outline – Fall 2015
Page 3 of 3
Tentative Schedule – Fall 2015
"In the event of extraordinary circumstances beyond the University's control, the content and/or evaluation scheme in
this course is subject to change".
Wk Date Topic Chapter/Sections Assignments (suggested problems)
1 Sept. 14 Introduction: Power electronic systems
1.1 – 1.7 , 3.1 – 3.2
P1-1, P1-3, P1-4, P3-6, P3-7
2 Sept. 21 Power semiconductor switches
2.1 – 2.12 Assign. #1
3 Sept. 28 Line frequency AC-DC converters (diodes)
5.1, 5.2, 5.3.1, 5.3.4.2, 5.3.4.4, 5.5, 5.6.1, 5.6.4, 5.7, 5.9
P5-3, P5-4, P5-6, P5-23
4 Oct. 5 Line frequency AC-DC converters (thyristors)
6.1, 6.2, 6.3.1, 6.3.4, 6.4.1, 6.4.3
Assign. #2 P6-2, P6-5, P6-6, P6-13, P6-20
Oct. 12 Thanksgiving
5 Oct. 19 AC-DC (cont.) DC-DC converters
7.1, 7.2, 7.3.1, 7.3.2, 7.3.4, 7.4.1, 7.4.2, 7.4.4, 7.7, 7.8, R9.6
P7-1, P7-2, P7-7, P7-8, P7.18
6 Oct. 26 Midterm exam
(1.4 hour) DC-DC converters (cont.)
Exam on topics of week 1-4 (up to thyristor AC-DC converters)
Nov. 1, deadline for
academic
withdrawal Fall
courses
7 Nov. 2 DC-AC converters 8.1, 8.2, 8.3. Assign. #3 P8-1a, P8-10, P8-11
8 Nov. 9 DC-AC converters (cont)
8.4.1, 8.4.2, 8.4.5, 8.7
9 Nov. 16 Power electronic interfaces
8.6, 10.5.5, 18.1 – 18.6. Assign. #4 P18.2, P18.3
10 Nov. 23 High power DC transmission
17.1, 17.2 (HVDC) P17-2, P17-3
11 Nov. 30 AC controllers 6.2.1, 6.2.2, 16.3.3, 17.3.1, 17.2.4.2 R6.2, R6.4, R6.7
R6-1, R6-6, R6.8, R6-13 P17-5, P17-8 Assign. #5
12 Dec. 7 Utility applications: SVC, TCSC, STATCOM and renewables
17.3.3, 8.6.3, 17.4, 17.5 Additional papers
P17-6
13 Dec. 8 (Tuesday)
Review and additional examples
TBA Final exam All topics. Period: Dec. 9 to 22
CONCORDIA UNIVERSITY
DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING
Power Electronics (I) ELEC-433/6411
Assignment #1: Introduction
Due date: September 25th 2012
1) A 60 Hz three-phase Y-connected induction motor draws 50kVA at 0.85 lagging power
factor when supplied directly from a 400 VLL – 60 Hz source. A) Compute the equivalent RL
impedance of the motor for this condition. B) Assuming that the motor (represented by the
RL impedance) is connected to the source through a three-wire feeder with impedance of 0.05
+ j 0.01 Ω (per phase), what would be the active power developed by the motor? C) What
would be the three-phase losses in the feeder? D) Compute the reactive power required from
a capacitor bank placed in parallel to the motor to improve the power factor to 0.92 at the
load side of the feeder. E) For a per-phase equivalent circuit, show the phasor diagram of the
motor current, capacitor current, source current and source voltage (reference phasor).
2) Consider the circuit below regarding a three-phase diode rectifier with capacitive dc filter and
an LC input filter. The three-phase source is 110 VLL 60 Hz. One plot shows the waveforms
of the source voltage, capacitor voltage and output voltage, followed by the harmonic spectra
of the ac waveforms. The other shows the current in one phase of the source (iRLS) and that in
the input of the diode rectifier (iLf). The harmonic spectra of the latter are also shown. Based
on this: A) List the order of the harmonics found in both current waveforms; B) compute and
compare the magnitude of the harmonics and the THD of both currents. C) Compute the crest
factor of iLf. D) Compute the reactive power supplied by the (three-phase) capacitor bank.
CONCORDIA UNIVERSITY
DEPARTMENT OF ELETRICAL AND COMPUTER ENGINEERING
ELEC 433/6461 – Power Electronics/Power Electronics I
Assignment #1: Review of basic concepts and definitions
Due date: September 28 2015 in the mailbox of Dr. Lopes (EV5.175).
1) A 60 Hz three-phase induction motor draws 25kVA at 0.8 lagging power factor from a 220-VLL
source. It is desired to improve the power factor to 0.92 by connecting a capacitor bank in parallel
with the motor. A) Specify the required kVA (kVAr) rating of the capacitor bank. B) If the
capacitor bank is ∆-connected, find the value of the capacitors. C) Determine the line current
before and after the addition of the capacitor bank. D) For a per-phase equivalent circuit, show
the phasor diagram of the load current, capacitor current, source current and source voltage
(reference phasor).
2) A single-phase full-bridge diode rectifier was simulated with PSpice and the following results
were obtained: 1) Waveforms of the ac side current, ac side voltage and dc side voltage; 2)
Harmonic spectrum of the ac side current. Assuming that φ1 = 10°, compute: a) The total rms
value of the ac side current; b) The THD of the ac side current; c) The crest factor of the ac side
current; d) The active, reactive and apparent power absorbed by the converter; e) The power
factor and the displacement power factor of the converter.
Time
100ms 105ms 110ms 115ms 120ms 125ms 130ms 135ms 140ms 145ms 150ms
V(Rload:1) - V(Rload:2) V(Vs:+)
-200V
0V
200V
I(Ls)
-40A
0A
40A
SEL>>
Frequency
0Hz 0.1KHz 0.2KHz 0.3KHz 0.4KHz 0.5KHz 0.6KHz 0.7KHz 0.8KHz 0.9KHz 1.0KHz
I(Ls)
0A
4A
8A
12A
16A
(900.000,439.489m)
(780.000,468.070m)
(660.000,922.143m)
(540.000,1.0312)
(420.000,2.2032)
(300.000,6.4795)
(180.000,11.734)
(60.000,15.348)
CONCORDIA UNIVERSITY
DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING
Power Electronics (I) ELEC-433/6411
Assignment #2: Line frequency AC-DC converters
Due date: October 10 2012
1) A three-phase diode rectifier is used to supply the field current of a dc motor
whose ratings are: 200 V, 10A. Assume that the dc current of the rectifier is ripple
free (pure dc). A) Calculate the turns ratio of a transformer and its apparent power
to interface the rectifier to a 220V/60 Hz source. B) Calculate the voltage (peak)
and current (average and RMS) ratings of the diodes. C) Explain why the strength
of the power source affects significantly the voltage distortion created by the
rectifier at the PCC (Point of Common Coupling).
2) Consider a single-phase thyristor-based AC-DC converter supplying a highly
inductive load with a resistance of 5 ohms. The grid voltage is 120V/60Hz but it
is allowed to vary by +/-10% of its rated value. A) Calculate the range of firing
angle of the thyristors so that the load voltage can be kept at 96 V at all times. B)
Compute the (maximum) rms values of the current harmonics that could occur in
the ac side of the AC-DC converter. C) Consider that a free-wheeling diode is
placed in parallel with the load. Describe how the circuit would operate in this
case. D) Derive an equation for the average value of the load voltage (with the
free-wheeling diode.) E) Calculate the “new” range of firing angle of the
thyristors so that the load voltage can be kept at 96 V at all times (with the free-
wheeling diode.) F) Compute the voltage ratings required from the free-wheeling
diode as well as its required minimum average current.
CONCORDIA UNIVERSITY
DEPARTMENT OF ELETRICAL AND COMPUTER ENGINEERING
ELEC 433/6461 – Power Electronics/Power Electronics I
Assignment #2: AC-DC converters
Due date: October 13 2015 at NOON in the mailbox of Dr. Lopes (EV5.175).
1) One wishes to supply 5 kW to a highly inductive DC load. There is a 4-wire 220VLL, 60 Hz three-phase source
with impedances of Rs = 0.1 Ω and Ls = 100 µH available at the site. Thus, it is possible to use either a single-
phase or a three-phase AC-DC converter connected as shown in the figure below. The breakers were included and
controlled so that the single-phase is supplied from t = 0s to 1.5s and the three-phase from 1.5s to 2s. The load
impedances of the 2 converters where computed so that one obtains rated load power (5kW) with the average
output/load voltage one gets when neglecting the voltage drops in the line impedances. Compute: A) The current
(RMS and average) and the voltage (peak) ratings of the diodes of both AC-DC converters, neglecting the voltage
drop across the source impedance; B) The total ohmic power losses on the impedances of the source due to the
single-phase and the three-phase converters; C) The voltage drop (fundamental component) across the
impedances of the source, due to the input currents of the single-phase and three-phase converters. Note: The
PSIM circuit is available on the course web site for additional tests.
2) The field winding of a DC machine, with resistance of 2 Ω and an inductance of 32mH, is to be fed with 400 V,
using a three-phase 220 VLL/60 Hz source a Y:Y transformer and a diode rectifier, all assumed “ideal”. A)
Considering that the grid voltage does not vary much, compute the turns ratio of the transformer as well as its
(total) apparent power (S3φ= 3S1φ). Recall that in this case, the harmonic components of the input current of the
AC-DC converter need to be taken into consideration. Now, assume that the grid voltage can vary by +/- 10 %
and that a thyristor AC-DC converter is used for regulating the load voltage at 400 V using the same transformer.
B) what would be the minimum and maximum values of firing angle (α) and when would they be used, (Vsmax or
Vsmin)? C) For Vs = Vsmax, compute the active and the reactive powers absorbed by the AC-DC converter.