The history of the power electronics
industry is briefly reviewed and discussion is given showing how components and
circuits have evolved from selenium rectifiers to high temperature electronics.
A framework provides a comprehensive
approach to specifying systems. Electrical input and output requirements are
developed in detail separating out what is assumed and is commonly misunderstood
Nearly all designs must meet the
scrutiny of UL, CE, CSA, etc. A discussion is given regarding which
certification is required and what steps need to be taken.
Mother nature strongly objects to
abrupt changes and easily provides excessive voltage transients, particularly
when currents in inductors are interrupted. An in-depth look at the effects of
circuit parasitics is given along with good design practices. This is an
essential presentation to all in power electronics design.
The gambit of linear, hard-switched,
quasi- and fully-resonant, and resonant-transition topologies are described and
criteria for matching topology to application are given. Details are given on
design with linear regulators. (This is an introduction to Switch-mode and
Resonant Topologies.)
The workhorse of power electronics is
switch-mode topologies. A Buck Converter design is used as an example to show
the reality of switch design. Design calculations, predicted waveforms and
component specifications are given.
This is an advanced topic and addresses
the growing need in very high efficiency circuits. Resonant topologies offer
many operating modes not obvious and require special analysis approaches.
There are many new components available
and some with particular operating limitations. Power resistors, switching and
filter capacitors, magnetics, sensors and fuses are described and characterized
with emphasis on how their use and rating is affected by high currents,
voltages and temperature. Component models and design tips are given. The
magnetics section is excluded if the "Magnetics Design" section is
presented
Magnetics design has never been easy.
This in-depth treatment of inductors and transformer is approached from
materials, modeling and direct design examples. Parasitics are quantified as
both elements to be minimized or used as part of resonant switching circuits. A
magnetic amplifier design as used in multiple-output power supplies is also
reviewed. When cost is considered, more attention may needed in mounting and
circuit partitioning.
Considerable cost in components and
certification is found in the input circuitry. How to minimize the design time,
components and the certification cycle is a topic unto itself. The filtering is
a major cost center and needs in-depth understanding.
Selected devices, such as power Diodes,
MOSFETS, IGBTs, SCRs and GTOs, are described in detail along with drive
requirements and techniques. Though some devices are of old origin, many are
now used in protection and fault management circuits. Device models are
developed as part of the characterization. Overlooked devices, such as the
unijunction transistor, are also included.
To achieve very low output voltages at
modest efficiencies, the voltage drop of rectifiers must be reduced. One
approach uses a MOSFET as a switched diode. However, there are many tradeoffs
in cost and complexity, besides intellectual property.
Power electronic circuits convert many
types of energy, such as electric, magnetic and thermal. Why do only electrical
designs? This presentation moves from physical specification through
characterization of different packaging approaches and characterization of
materials. Given is a comprehensive framework to identify packaging issues and
is essential of all designers.
The end product is a physical circuit
and this circuit provides many parasitics that must be considered during
electrical design. This presentation characterizes the physical circuit and the
effects on the electrical circuit behavior. It is a must for high density and
high frequency design. (This is a lengthy presentation.)
Several approaches are now developing
in power electronics control: vendor supplied ASIC, mixed signal and all
digital. At the foundation remains basic control principals for multi-loop
control. This presentation develops the basics of power electronics control,
such as stability, voltage, peak current, average current. Models are given as
used in simulators.
There are many options to circuit
simulation. Designers can now complete nearly 90% of their designs through
simulation. What is available and what are the limitations? Demonstration of
macro and behavioral modeling is applied to components and circuits in power
switching applications. Several case studies are given with emphasis on where
certain simulators have quirks and limitations. If requested, spatial
simulators for electromagnetic and thermal analysis can also be included.
A unique "cradle to grave"
design example of a pump motor drive is provided. This case-study highlights,
top down, how the physical design can drive partitioning and modularization in
a product design rather than the electrical requirements. The result provides
the lowest cost bottom-line solution.
Access to on-line design notes and even
software tools, has never been greater. However, "app note designs"
do have limitations that can cause final difficulties in designed around early.
Key app notes are identified and several designs discussed in detail.
A company-supplied problem will be
accepted and a comprehensive "cradle to grave" electrical design will
be performed. This proceeds from review of specifications through complete
design including identification of components. The procedure follows a
framework and demonstrates the thinking process.