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Op-amp equivalent of Scott Connected Trasformers ?
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Tim Craig
Jul 29, 1995, 3:00:00 AM7/29/95
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I need to make a quick and dirty converter from a resolver to 3 phase
(synchro). Normally I would construct a Scott Connected tranformer
arrangement with a couple of small transformers.
(synchro). Normally I would construct a Scott Connected tranformer
arrangement with a couple of small transformers.
However,, has anybody a pointer to an equivalent circuit based on an op-amp
matrix ? The plan is then to synchronously demodulate the 3 derrived
phases, filter them and feed them into a trio of zero volt referenced
comparators. Et voila - simulated hall effect outputs from a resolver based
brushless motor.
Tim
Larry Morris
Aug 1, 1995, 3:00:00 AM8/1/95
to
t...@tecno.demon.co.uk (Tim Craig) wrote:
>I need to make a quick and dirty converter from a resolver to 3 phase
>(synchro). Normally I would construct a Scott Connected tranformer
>arrangement with a couple of small transformers.
>
>However,, has anybody a pointer to an equivalent circuit based on an op-amp
>matrix ?
>I need to make a quick and dirty converter from a resolver to 3 phase
>(synchro). Normally I would construct a Scott Connected tranformer
>arrangement with a couple of small transformers.
>
>However,, has anybody a pointer to an equivalent circuit based on an op-amp
>matrix ?
From Sine and Cosine inputs, the X, Y, and Z synchro outputs are
Z = Cosine/sqrt(3)
Y = (Sine - Z)/2
X = -(Sine + Z)/2
1/sqrt(3) can be approximated to better than .01% by 56/97 or 153/265.
A voltage divider made of standard 1% values such as 10k and 13.7k will
give a nominal gain of 1/sqrt(3) within about .13%.
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