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Old 09-07-2014, 07:18 PM   #1092 (permalink)
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Ok, answering a bunch of my own questions...

In reviewing some of my old, notes, it appears that the resolver actually passed higher frequencies BETTER. There is LESS attenuation at a high carrier frequency than a low one. The main advantage of using a low ( 5KHz > 20KHz ) carrier frequency is that the output is more stable. In my tests, there was about a 4.8:1 ratio of input to output at the low frequencies, and about 2:1 ratio between 50KHz > 75KHz. The only downside is that there is more sensitivity to changes in carrier frequency.

However, that 50KHz frequency that's used to drive the driver boards is very stable, so really this is not an issue. So, the best setup would be to buffer the 50KHz with an op-amp (so I don't affect the other users).

A 50KHz carrier frequency also provides really good accuracy for the resolver, because even if the motor is turning at 12,000 rpm, there will still be 62 data points per sine peak.

- E*clipse
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