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Old 10-10-2014, 04:22 PM   #1186 (permalink)
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I'll second that. Using PI or PID control is a very powerful technique. It's not exactly intuitive, as it was the basis for two mechanical engineering controls classes I took many moons ago. The diversity of the technique is amazing. I have a PID controller for my espresso machine to control the water temperature.

Perhaps I can dust off some of those old books and remind myself how it worked, but you'll probably figure it out faster.

I'd also like a copy of the code - so I can critique your style. Just kidding! I may be able to help a bit with integrating the resolver stuff....

- E*clipse

Originally Posted by thingstodo View Post
The Industrial VFDs that I use at work refer to 2 tests. One is a 'Static Tune', where the motor is coupled to a load. This is not as accurate but it gets you some numbers that are close. The test mentions something about a DC voltage applied, I'm guessing it's at least 3 DC voltages to involve all of the coils, but it's a short duration and somehow they measure inductance and resistance. The DC is sequenced so that it does not induce rotation.

The other is a 'Dynamic Tune', where the motor is decoupled from the load, motor only. The motor gets a series of pulses and rotates 1/4 to 1/2 a turn.

Each vendor appears to do it differently (slightly) and considers this part of their own 'secret sauce'. I can't find any documentation on how it's done. I'd like to try this method, since it is one of very few things that I've seen consistent from one VFD to another. But that's all the info I have so it's not much help.

On another topic, if you are open to it, I'd like a copy of the source. PM, or ftp, or whatever works for you.

I'll likely get lost trying to follow it .. but I may not.
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