In this brief lecture,
I'm going to summarize the technical content of the power
electronics courses and specializations that we will offer for
credit. So, that the area of power electronics
is quite broad, and it incorporates elements from a number of different
sub-fields of electrical engineering. Certainly it's based on analog
circuits and electronic devices, control systems and
feedback systems are very important. We have applications in power systems. The design of the magnetics
is very important, and an important part of the design
of a power converter. Often we interface electric machines, and
often we will use numerical simulation. So in this course,
Introduction to Power Electronics ECEA, five seven zero zero, I'm going to
assume that you have some undergraduate prerequisite knowledge in analog
circuits and electronics. I'm not going to assume anything else. And this first course will
cover power converters, really from the standpoint of analog
circuits and electronic devices. So, this Course 1 that is 4 weeks long, plus a proctored exam at the end,
really is summarized by this slide. In the first week, we're going to do
simulation of a switching converter, so you will use LTspice to look at the wave
forms of an actual switching converter. We'll learn techniques of steady
state converter analysis. So if you have a switching converter
that has switched waveforms, like these, how to analyze them to
find things like the output voltage or the inductor currents of
the converter circuit. We'll then develop equivalent
circuit models, such as this one, that model the basic conversion
properties of a switching converter, as well as modeling losses in the circuit. And this kind of equivalent circuit, then can be used to analyze a converter to
predict things like its efficiency curves. The follow on Course 2,
called Converter Circuits ECE a5701, goes into more detail in how
these switching converters work. We'll talk about how to realize
the switches using power transistors and diodes. So we'll talk some about
power semiconductor devices. And one of the important things to
learn here, is how they switch, and where switching loss comes from. So here are some typical wave forms of
the diode reverse recovery process, which is one of the major sources of
switching loss in a practical converter. So we'll learn how to model that. We'll learn about the different important
power devices, such as the power MOSFET. We're going to analyze, what's known as
the discontinuous conduction mode that occurs in some switching converters. And we'll look at different
converter circuits or circuit topologies,
including ones with transformer isolation. Here is a well-known transformer isolated
converter, known as the forward converter, which is one of the isolated
circuits that we we'll discuss. The third course in this specialization,
is called Converter Control, and this is an introduction to applying
feedback to a switching converter. Generally we want to regulate an output
voltage, or an inductor current, or some similar quantity. So here's an example of
a switching converter, circuit known as the buck
converter with a feedback loop around it to control the output
voltage of this buck converter. This is a pretty complex system,
and we have switched waveforms that are fairly complicated, and so
in Course 3 we will learn how to model the important voltage and
current components in the circuit, and derive equivalent circuits that we
can use to design feedback loops. Course 3 will cover an introduction, then, to feedback in the context
of switching converters. The last course ECE a5704, is an introduction to magnetics for
switching converters. So we'll talk there about
just how basic inductors and transformers work, talk about their AC and DC loss mechanisms,
in both the core and the winding. And we'll talk about how to
design basic inductors and transformers for switching converters. Simulation is a recurring theme
in this specialization and in the following ones as well. Here,we're going to use
LTspice in this course, and in fact in the first homework this week, you will use LTspice to simulate the basic
waveforms of a switching converter. Here is actually an example from
the follow on specialization, which gets into more detail and
more advanced topics in converter control. But this is an average model
of a switching converter and it's feedback loop that can predict things
like small signal transfer functions, in which can be used to
design the feedback loops. That follow on specialization, goes
into more advanced control techniques, such as current mode control,
power factor correction, input filter design,
digital control, and related topics. We have a graduate certificate that
we offer through this program, the graduate certificate is comprised
of this specialization the follow on control specialization, and
then a capstone design project. And in this project you will design
the power conversion system for a taught USB Type-C interface, which interfaces a computer and
its battery to a USB cable. So this involves selection of the
converter circuits, design of the power stage design of the magnetics,
design of the analog controller, and then simulation and verification
that your design meets requirements. Here is the Prerequisite Chain for
this specialization. So this course,
Introduction to Power Electronics, assumes a basic undergraduate knowledge of
circuits and electronics, but that's all. It is prerequisite to the second
course in the specialization, called Converter Circuits,
which I mentioned before, that one is prerequisite
to the final two courses. So the control course and the magnetics
design course, both assume that you've had, or gotten through
the second converter circuits course. So I look forward to your
participation in this course. I would encourage you to take
advantage of the discussion forums. And in the credit course, we also have
course facilitators, who will hold regular office hours, and I urge you to
take advantage of their help as well. And I hope that you find
this course rewarding.