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

[Anaerin]

How on earth did this thread fall off the front page?

Oh yeah, there's been no posts in over a month.

Wait, NO POSTS IN OVER A MONTH?! What on earth happened? Are we working on Valve Time (http : // developer.valvesoftware.com/wiki/Valve_Time) here?

[TheSGC]

Been on vacation and getting ready for another one, (but it's EV related!). My prototype has been sitting in front of me for quite some time, but I have been too busy to get cracking on it. I have a 22 hour flight coming up this weekend that I will be trying to get my schematics on the computer and I am trying to get some more information on the encoder on my motor.

I recently got a decent look at a Azure DMOC445 and I have changed a few things in my design to improve on it. The DMOC445 is rather underpowered, but when I opened it up it was nearly identical to what I was designing, so I went back and made changes.

[dave koller]

Originally Posted by TheSGC

I will be trying to get my schematics on the computer and I am trying to get some more information on the encoder on my motor.

And I am lurking and waiting David! Have fun... Summer is flying by - all I do is work and soon school starts and XC running (coaching) for me ...

[roguethunder]

So, there was alot of talk about what program to write up the PCB and schematics in. There's a new fairly polished free program called DesignSpark PCB. Supports import from Eagle among other things... Outputs gerber extended in theory(haven't gotten my hands dirty much yet) and has both PCB and Schematic support in one program.
DesignSpark PCB | DesignSpark
No weird restrictions I can see either. No horrid outdatedness... Not an exclusive closed format...
Pretty incredible all around. Though a little new/untested.

[MPaulHolmes]

Oh heck ya, Rogue... Thunder! Kachigga Kachigga! I downloaded it this morning, and I"m installing it now. Thanks!

[Automcdonough]

looks like I'm not too late to this party. I'm an EE with experience making DC-DC converters and rectifiers.. mostly in the 300W~2kW range.. 360VDC input side.
I just now came across this in my quest to DIY a motor driver.. I might have had some circuits to toss at you for the DC version but I'd rather concentrate on this as I'm on a mission for AC.

Most of what I did was analog power, none of our stuff used microcontrollers because they are too slow for a safe short-circuit current limit, and too slow for stable control loop when the system runs at 100KHz.

My approach might be overkill considering we're going to be at 1/10 the frequency, the micro can probably keep up with things. I wanted the micro to output four 0~5V analogs down to the power board. First 3 are PWM duty cycle for each leg, 4th is current limit setpoint. Could also be sent as digital w/ analog conversion being done on power circuit.

On the power board would be 3 PWM drivers or one of those IR control chips with a 100% analog current limit that operates independent of the micro (would use setpoint or hardwired max, whichever is lower). Motor speed, current of each leg, bus voltage, bus current, temperature, etc all would be conveyed back up to the micro. Power board would also contain shoot-thru protection and some other un****withable circuits, as well as micro controllable ones like undervoltage lockout, overvoltage lockout, overtemperature derate/shutdown.. all with hardware maximums that should hit if the micro goes on holiday. For the most part the analog circuits will be cheap and simple, hopefully avoiding expensive LEM's and whatnot. Compared to what I'm used to this low-frequency high-inductance circuit should be cake.

I have a good feel for what to do with all this but when it comes to AC motor theory and choosing+programming the micro itself I'm pretty weak.

Also I should mention that I intend to drive 480V motors, DC bus will tolerate at least 800V. I was considering breaking that boost/buck front-end for the battery into a separate box which would watchdog the batteries carefully, mostly because I wanted to use 4 motor drivers (electronic throttle control..)

[Automcdonough]

I'm a little on the fence about the voltage, good chance I will cave in and do 360V bus

[MPaulHolmes]

DesignSpark is working well. While I wait the couple days for the SR control boards to get here (and since the prototype software for the SR controller is ready), I'm doing a control board for the AC controller. 6 of the VLA106-15151. I'm also modifying the undervoltage circuits for hardware disable of the mosfet drivers. All 6 will turn off if a single undervoltage event happens.

Right now I'm converting all the stupid libraries over to DesignSpark. The rough draft board will take about 1 week I think to get designed and routed. I'm doing it all through-hole I think. It will just be 0-15v drivers, which will work fine at a relatively slower frequency for IGBTs. I can't wait to test it out first on that little weenie module I bought, and then on the 6-pac that was sent to me during christmas! The software is not going to be that bad I think. I used to program old school video games, and had to do lots of trigonometric transformations, so the clarke, park, and inverses won't be too bad to implement I think. It's always 10 times harder than you think it will be, but if you go in knowing that, then it's only like 5 times harder! So twice as easy as you think! hahaha

[jackbauer]

........interest you in an ipm..........?

[MPaulHolmes]

That would probably be easier. hahaha