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From: firstname.lastname@example.org (Bill Sloman)
Subject: Re: How to construct PWM pure sine wave inverter ?
Date: 16 Oct 2002 14:53:59 -0700
References: <email@example.com> <firstname.lastname@example.org> <email@example.com>
NNTP-Posting-Date: 16 Oct 2002 21:53:59 GMT
firstname.lastname@example.org (Wouter van Ooijen (www.voti.nl)) wrote in message news:<email@example.com>...
> >with a fixed frequency source, but for a variable frequency source, the DDS
> >technique of driving a D/A converter from a phase accumulator via a look-up
> >table is to be preferred.
> Does not ring a bell to me. URL?
www.analog.com then look for application notes on the AD9850 and their
other DDS chips. It is actually an old idea, but when Analog Devices
squeezed it all into one chip it got a lot cheaper.
> >For power applications, where you really need PWM, Don Lancaster's magic
> >sine waves probably have too many switching edges to be acceptable - each
> >transition dumps a lump of energy into the switch and you need to ration the
> >number of transitions.
> Do you refer to the 'old' MSW's (with fixed-distance events) or the
> 'new' steplocked MSW's? I am working on a steplock-24 right now, which
> has just 24 transitions per full cycle. Is that much more than with
> another approach?
Don't know. I last looked at magic sine-waves a couple of years ago,
and wasted a lot of time working out that they weren't going to help
me. I don't recall seeing any "steplock" sequences then, so they might
be new and different.
Bill Sloman, Nijmegen
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