Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control

[MPaulHolmes]

Sure, just email me at PandSPowerElectronics@gmail.com

[59Morris]

MPaulHomes, The controller config states the range for "current-sensor-amps-per-volt" to be 0-480. I purchased the 600A current sensors (bigger is better?) so can I use 960 for this value? The config accepts the setting, but I want to be sure the imbedded software will also be happy with it.

[esali1987]

Anyone have a recommendation of which encoder would be good to use for the board to add on if I dont already have one? Thanks

[thingstodo]

Originally Posted by esali1987

Anyone have a recommendation of which encoder would be good to use for the board to add on if I dont already have one? Thanks

I don't have a recommendation for you. It can get pricey. A through-shaft encoder with 150 PPR or more will start at $500 new.

60 pulses per revolution is enough for good control. It boils down to where you have enough space to put it, what product you can find that will fit, and how you can mount the unit in that space.

There are through-shaft encoders, where the motor shaft sticks through the encoder disc and the rest of the encoder is sort of supported by that shaft.

There are magnets that you can super-glue to the end of an exposed shaft and a small PC board with a chip mounted on it does the magnet sensing and gives you pulses.

And there are ... many ways .. of putting a toothed gear of some sort onto the motor shaft, or monitoring a driven shaft inside the gearbox, or even driving a pulley or gear specifically for the encoder .... all of them give you pulses that work OK for control but don't show you which direction the motor is going. 12-24V DC Inductive switches are used in this last case. Depending on your RPM and how many pulses per revolution you want, they can start at $50 ... if you can fit them where they need to go.

[esali1987]

I also have a Siemens 1FV motor with this encoder attached with T, S, R, (+), and (-). This seems like outputs would be sinusoidal for the three phases. This probably would not work right?
Thanks

[thingstodo]

Originally Posted by esali1987

I also have a Siemens 1FV motor with this encoder attached with T, S, R, (+), and (-). This seems like outputs would be sinusoidal for the three phases. This probably would not work right?
Thanks

I think sinusoidal is for a resolver, not an encoder. And I think you get sine, cos as signals, not one per phase? Not sure. Sorry. This looks fairly close to your diagram but not exact.

https://www.google.com/search?q=siem...a3QwdgM:&vet=1

What other feedback systems are out there?

My encoder on my siemens has A, Abar, B, Bbar, Z, Zbar, + and -. It's a 7 or 8 pin round connector that is hard to source. It sort of looks like the microphone connectors from the 60's and 70's. The encoder runs on 24VDC so I put the output signals through a voltage divider resistor network, and took the 5V-ish signals to Paul's control board. It worked well, even with unsheolded cat5 cable, run across the power cables, and jury-rigged to control board.

[MPaulHolmes]

I don't really understand what T, S, and R are. Do you have any waveforms?

[ale0502]

Hi everyone, I have a quick question, does the controller need to measure the voltage of the battery bank or any other point of the setup?

thanks

[MPaulHolmes]

It doesn't use the battery voltage for anything at this time.

[esali1987]

Ok Yeah ill need to get an ocsilliscope for that part for sure and I saw, Paul, that you have a resolver to encoder board. SWEET!!

Another thing came up that I am curious about. I can only seem to get the board to put out a signal if the pickit3 is hooked up and not with the USB terminal. Is the onboard USB just for programming as a "Program Mode" and need to be disconnected for "Run Mode"? I have got my motor to move when the PICKIT3 is hooked up only.

Thanks