Dear Dennis...
EN-Genius Network's Dennis Feucht answers your design
queries in his new Circuit Design Clinic!
April, 2009
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EN-Genius Network presents a new, interactive
analog design service to readers! Send us your design questions (with
relevant data; schematics in JPEG or GIF, please) for some free
engineering advice from EN-Genius Network's circuit
consultant, Dennis Feucht, on how you might solve a design problem or
improve circuit performance. Submissions may be edited for clarity or
brevity, and submitters and their email addresses will remain anonymous
(unless otherwise indicated). Please send your questions to Dennis here.
Switching Power Amplifiers from Power Converters
Some Solutions
by Dennis L Feucht
In a previous article, some of the shortcomings of present-day switching amplifiers for motor drives were described. In this article, some hints at directions leading to more precise amplifiers are offered based on power converter circuit topologies.
The place to begin in the search for a better switching amplifier is with one that was conceptually well ahead of its time for, up until now, it has found little application, though its weaknesses are not severe. In the late 1970s, Slobodan Cuk extended his discovery of using magnetic devices, or transductors, at their boundary between transformer and coupled-inductor behavior. At this boundary, both windings of the transductor drive each other by each having the same voltage applied across their windings. Ordinarily, this is considered a degenerate circuit state, but when the leakage inductance is included in the modeling, an interesting effect occurs, that of “steering” the ac or ripple component of the current into one winding or the other. The effect has been explained in the TechNote Cuk-Based Converter Concepts: Part 1: Basic Converter Configurations with Ripple-Current Steering.
...download complete article here (197 KB PDF)
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