Electrical Engineering 585 Introduction to Power Electronics
Commutation. Diode rectifiers. Fully controlled 3-phase rectifiers. Choppers, inverters, ac controllers. Single-phase switch mode converters: dc-to-dc, ac-to-dc, dc-to-ac. Circuit and state-space averaging techniques. Switching devices and magnetics.
Course Hours: H(3-2/2)
Calendar Reference: http://www.ucalgary.ca/pubs/calendar/current/electrical-engineering.html#7645
In this course we will review then we will investigate further the following concepts: power balance, averaging, root mean square, orthogonality, commutation, and most especially the definition of inductance expressed as v dt = L di, with its many interpretations: as a definite integral used for commutation interval calculation; as a difference equation used for current ripple calculation (for one state of a converter in a time interval approximated by dt); in AC steady-state analysis giving an average inductor voltage of zero and giving us the principle of Volt second balance; in DC steady-state (ie, with a constant value of average inductor current) once again giving an average inductor voltage of zero and once again giving us the principle of Volt second balance but this time applied to DC; as a time-scale independent form, namely, v d θ = ωL di allowing average and rms calculations for any period of the cycle; in Laplace form, V permitting ripple current approximations; and in Laplace-Fourier form, V= I h ωL
= I
ωL giving us current amplitude calculations at each harmonic frequency. All these concepts will then be employed in the time-domain steady-state analysis of several power converters.
With an emphasis on steady-state operation (though we need to know that power-up and other transients are also considered as well in converter design practice), we will study three classes of non-linear, or switching, power converters, namely: (a) Diode
Based Power Converter Topologies, where we will investigate low-power (ie, below
1.5kW) single-phase diode rectifiers as well as the high power full-bridge 3-phase diode rectifier that is employed in kilo-Watt to mega-Watt applications; (b) Thyristor Based
Power Converter Topologies, where several types of conventional high power converters will be examined, including the fully-controlled 3-phase rectifier, the dc chopper, the sixstep 3-phase inverter (with a little bit of frequency domain analysis), and the singlephase ac controller; and (c) Transistor Based Power Converter Topologies, sometimes called switch mode converters, that have proven themselves at sub-kilowatt power levels and are becoming popular at higher power levels up to mega-Watts. The three basic switch mode converters that we will study in the context of low power applications are the buck, boost and inverting converters. We will also study two isolated types of switch mode converters, namely, the hybrid-bridge forward converter and the flyback converter.
Our main scholastic objectives of this course are two fold: (1) To be able to sketch steady-state waveforms for the most common industrial and commercial power converters. We will have lots of practice using our KVL (Kirchhoff Voltage Law) and
KCL (Kirchhoff Current Law) circuit analysis skills; and (2) To know which inductor interpretation to use, dependant upon the objective of our analysis, e.g. to find peak-topeak current ripple in a DC chopper: for high ripple (we will determine in this course what

“high” means) we use the differential equation, but for low ripple we use the difference equation form. In each case we will select the calculation method that is the most succinct – a skill that is particularly useful when performing original design work.
At the end of this course (where each point below is taken from each chapter of our course notes at http://www2.enel.ucalgary.ca/People/Nowicki/), you will be able to:
distinguish between linear and non-linear power converter operation
recognize when commutation takes place and calculate the commutation period
use the principle of power balance as a check on your circuit analysis perform quick “back of the envelope” average and rms calculations and apply the principle of othogonality to aid you in your rms calculations; to know that the terms “average” and “DC” are interchangeable in the context of power converters
for diode rectifiers: sketch steady-state waveforms; calculate the average output voltage and input power factor, without and with the inclusion of line inductance; and also estimate output current ripple for inductive loads using an approximate
“effective ripple impedance”
for SCR rectifiers: sketch steady-state waveforms; calculate the average output voltage and input power factor, as a function of the firing angle, without and with the inclusion of line inductance; estimate the commutation interval with an approximate commutation inductor voltage
for DC choppers: sketch steady-state waveforms including a piece-wise approximation when the current ripple is less than 50%; calculate the average output voltage by applying KVL to averaged element voltages; estimate output current ripple for each state of the converter from the definition of inductance expressed as v dt = L di
for the 3-phase SCR Voltage Source Inverter: sketch steady-state waveforms for
LR loads; estimate the current ripple using Fourier analysis
for the single-phase AC Controller: sketch steady-state waveforms for LR loads in discontinuous and continuous current modes; and to know which mode the controller is operating in
for buck, boost and inverting DC-to-DC converters: sketch steady-state waveforms; determine the DC input to output voltage transfer function using the principle of Volt second balance (a direct consequence of an inductance in DC steady-state); determine the boundary condition, if any, between continuous and discontinuous mode; be able to estimate the output voltage ripple from the definition of capacitance expressed as i dt = C dv (in direct analogy with current ripple calculations for inductance)
for the transformer isolated Forward and Flyback DC-to-DC converters: sketch steady-state waveforms; be able to invent/synthesize these converters starting with a buck or inverting converter and thus determine the DC input to output voltage transfer function by extension; determine the DC input to output voltage transfer function using the principle of Volt second balance; and to know which parameters of a transformer have the greatest effect on converter operation.
Schulich School of Engineering
ENEL585 Course Outline page 2 of 5

Section
L01
B01
B02
Days of the
Week
MWF
F
F
Start
Time
12:00
10:00
10:00
Duration
(Minutes)
50
110
110
Location
SB 146
ENA 06
ENA 06
Course Instructor
Section Name
L01, B01-02 E. Nowicki
Phone Office Email
403-220-5006 ENA 206F enowicki@ucalgary.ca
Teaching Assistants
Section Name
B01-02
B01-02
Arif Al-Judi
Nacer Benaifa
Phone
403-891-3406
587-888-9385
Office Email
ENA206L arifaljudi@gmail.com
ENA206D nacer.benaifa@gmail.com
The following examinations will be held in this course:
6 in-class Quizzes: closed book, closed notes; 20min Mndys: Spt 20, Oct 4,18, Nov 1, 15, 29
In-class Midterm: closed book, closed notes; 1 hour Oct 25
Final exam: 3 hours, Registrar scheduled (closed book, closed notes, formula sheet provided) Note: The timetable for Registrar Scheduled exams can be found at the
University’s Enrolment Services website, http://www.ucalgary.ca/registrar/.
Only non-programmable calculators may be used during examinations.
The final grade in this course will be based on the following components:
Component Weight
Labs
Quizzes
Midterm Examination
Final Examination
TOTAL
5 %
20 %
25 %
50 %
100 %
Schulich School of Engineering
ENEL585 Course Outline page 3 of 5

Notes:
1. It is not necessary to earn a passing grade on the final exam in order to pass the course as a whole.
2. The laboratories will require one pre-lab exercise per lab group, that is marked at the beginning of the lab. Observations and Analysis will be marked near the end of the laboratory period.
3. Of the six in-class quizzes, the best four will be counted for grading purposes.
There will also be six take-home quizzes which will not be graded. Solutions to all quizzes will be posted at http://www2.enel.ucalgary.ca/People/Nowicki/
Handouts of class material (in the form of chapters as related to each week of class) will be made available from Ed’s ENEL585 website: http://www2.enel.ucalgary.ca/People/Nowicki/ (scroll to the bottom of the ENEL585 page)
These handouts will provide you with the necessary theory for this course with additional worked problems available from the website where quiz and exam material from previous years is posted.
The following are reference textbooks only. They are NOT required for this course:
Title
Author(s)
Edition, Year
Publisher
Title
Author(s)
Edition, Year
Publisher
Principles of Power Electronics
Kassakian, Schlecht, Verghese
1st Edition, 1991
Addison Wesley
Power Electronics: Converters, Applications and Design
N Mohan, T Undeland, W Robbins
2nd Edition or higher
John Wiley
Schulich School of Engineering
ENEL585 Course Outline page 4 of 5

All Schulich School of Engineering students and instructors have a responsibility to familiarize themselves with the policies described in the Schulich School of Engineering
Advising Syllabus available at: http://schulich.ucalgary.ca/undergraduate/advising
The laboratories are scheduled as follows, all in room ENA06:
Lab 1 B01 Friday Oct. 15, 10:00-11:50AM
Lab 1 B02 Friday Oct. 22, 10:00-11:50AM
Lab 2 B01 Friday Oct. 29, 10:00-11:50AM
Lab 2 B02 Friday Nov. 5, 10:00-11:50AM
Lab 3 B01 Friday Nov. 19, 10:00-11:50AM
Lab 3 B02 Friday Nov. 26, 10:00-11:50AM
Template revised on 6 May 2010 (RWB)
Schulich School of Engineering
ENEL585 Course Outline page 5 of 5