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

[Astro]

Originally Posted by MPaulHolmes

...Thankfully, I don't teach at Maricopa HS. I used to teach at a high school for one horrible year...

Teachers and Nurses, under appreciated, under paid and totally insane.
Dealing with one teenager is difficult enough, trying to manage a entire classroom of them, that would be about as easy as herding cats.

[MPaulHolmes]

Does that PM synchronous motor need the oil inside for it to turn at all? How did you spin the motor to see the resolver waveforms, e*clipse?

[thingstodo]

Originally Posted by Astro

Teachers and Nurses, under appreciated, under paid and totally insane.
Dealing with one teenager is difficult enough, trying to manage a entire classroom of them, that would be about as easy as herding cats.

I beg to differ ... in order to 'herd cats' ... or get programmers pointed in the same direction to solve a problem ... it is necessary, for me at least, to CONVINCE each cat that THIS direction is where they WANT to go .. and that it was THEIR idea.

I've tried that method with teenagers and it does NOT work for me, at least!

[thingstodo]

Originally Posted by Astro

Do any of the other prototypers/beta testers need voltage boost? If not then developing the controller with 4 IGBT capability may be the way to go and save the 3 IGBT controller boards for people who don't need the voltage boost.

I have not sourced an AC motor as yet. I have a couple of 5 HP, 230VAC motors and a monster 30 HP 575VAC motor that I can use to test the controller. Nothing that I'd put into a car. Shipping the 3 pair IGBT controller board works for me. I'll test with the motors that I have when I receive the controller.

Paul - I'm wondering how much headroom is required on the max voltage for the IGBTs for a safety margin. Have you scoped the AC controller on a motor yet? (Or did I miss that?) Do you see any reflected wave?

Some boring background - In my day job we have problems with reflected waves on AC controller outputs and motor terminals, especially on motor leads over 200 feet. We don't really have any 'short' cable runs that I have experience with. We have installed load reactors, dv/dt filters, motor terminators, and in one memorable case a full sine wave filter (that cost almost as much as the controller). We have not lost IGBTs, as far as I know, but we regularly fail the insulation in the first wound coil in the AC motor's stator. Which phase is not predictable. The motor rewinder says something about 'the dv/dt is too high'. After the motor is rewound, it usually lasts longer, from 4000 to 10000 operating hours ... some as high as 25000 hours. The motor rewinder adds an extra 2 layers of insulating paper to the first coil of each phase, and one extra layer to the next 3 coils. Does that make any sense?

We are using a variety of AC controller vendors, and different vintages - Rockwell Powerflex, 1336 Plus; Siemens Master CUVC; Toshiba G3 and G7; Mitsubishi A560 and A760. The IGBTs on the drives that do fail (I take them apart to see what failed) appear to be rated between 1600V and 2200V. But they are driving 575V motors, and their DC bus voltages surge to 1000VDC, and we definitely have reflected waves in the 180% range.

[MPaulHolmes]

My thinking is a 300-350v dc bus for 600v IGBTs, and a 600-650v dc bus for 1200v IGBTs. I know a friend has made a 3 phase PM Synchronous inverter without snubbers and without any sort of filtering. It ran at 330v DC. He uses 600v intelligent power modules and film capacitors and doesn't have a problem. I haven't looked at the waveform with this setup yet. I'll still waiting on the boards to get here. I really hope reflected waves aren't a problem. The 3 phase leads should be very short though, so maybe it won't be a problem.

[freebeard]

EDIT: I'm not aware of any license for anything. I'm just hanging out at home, making stuff up as I go. haha. Thankfully, I don't teach at Maricopa HS. I used to teach at a high school for one horrible year. I don't actually have much of any sort of plans for anything. I'm just trying to make an AC controller that people can adapt and change the code how they see fit for their own needs. I don't see the software as too bad. The boost stage addition stuff, I'm told (by the EVTech list), will work, but it does add a level of complexity.

FWIW, you used the word 'open', that sets expectations in the larger world. People are going to read things into the use of the word. "Many eyes make all bugs shallow."

Open Source didn't start with software, it's the way lawyer practise for instance; and now it's grown to embrace embroidery patterns. Basically it employs copyright law to simulate anarchy. I'm not prepared to explain patent and copyright law vs the various flavors of Open Source and Creative Commons licensing—but it's worth knowing about if your doing this.

Some places to start:

• open source hardware - Google Search —this will lead to Local Motors, Wikipedia defs, Adafruit, etc.
• https://creativecommons.org/choose/ —CC licensing might apply to documentation and tutorials, or to everything.
• OpenGarages a source for 2014 Car Hacker's Owners Manual

Mentioning a specific high school was counterproductive. Makerspaces are labs that you subscribe to to get access to 3D printers, 5-axis mills and other items that exceed the capabilities of your average suburban garage.

Originally Posted by Astro

As soon as i read that i was visualising you pulling up to some traffic lights but instead of stopping you end up doing a big handbrake drift right through the intersection.

I'm not sure how use a brake to shoot through an intersection. I generally roll up to a stop, tap the brakes to demonstrate the taillights work and then use the handbrake as a hill-holder or hedge against getting rear ended.

Maybe with front-wheel drive and a stuck throttle?

[MPaulHolmes]

What should it be called if I just write code, and make hardware that anyone can change however they want? And I also don't want to bother to go through any licensing processes? Could I just say it's "do whatever you want with it" source, where "do whatever you want with it" has no official legal meaning, but does mean that people can do whatever they want?

edit: I didn't teach at Maricopa HS. I was just saying that you had mentioned a makerspace at Maricopa high school, and I thought that meant that you were wondering if I worked there like as a shop teacher or something. I didn't know what a maker space was. I actually taught high school in Washington state. Although it was awful, when I got a chance to teach college math, it made every day so glorious I could hardly stand it. I remember asking the dean of math and sciences at the college what to do if a student was disruptive. There were no IEPs, or any special meetings with parents, etc... He just said "throw their butt out". haha.

[MPaulHolmes]

I was reading the MIT license (I always wanted to go there, but the 1.2 gpa wouldn't allow it. lol). What if someone changes a little of the code? Are they then forced to include a message to everyone that others can use their code however they want? What if I want others to change the code and maybe keep it all sneaky and hidden if they feel like it, or shout it to the rooftops each line they typed if that's what they want? Reading about licenses is giving me an Office Space style case of the mondays.

Researching this, I feel like Wesley in The Princess Bride. "I just sucked 20 minutes of your life away. How do you feel?" <wesley starts crying> == <paul starts crying>

[Astro]

Originally Posted by freebeard

...
I'm not sure how use a brake to shoot through an intersection. I generally roll up to a stop, tap the brakes to demonstrate the taillights work and then use the handbrake as a hill-holder or hedge against getting rear ended.
Maybe with front-wheel drive and a stuck throttle?

It wasn't meant to be a comment on your driving ability, it was more a first reaction to the thought of a combined regen and handbrake setup.

Originally Posted by freebeard

...
As for regen, one of my driving postures is left hand on the wheel at six o'clock and right hand on the parking brake lever. Since I don't like a mushy brake pedal, but the parking brake has 6-7 clicks until it engages (max about 12 clicks) I would use that. And reverse the button so it's push to set. So basically three inputs.

Because you were talking about regen on the first few clicks of the handbrake and the only time i have seen someone use the handbrake at speed is the drift racers, where they use the handbrake to kick out the rear end of the car and get it going sideways.
Also i thought that reversing the button so it is push to set would remove the ratchet clicks so it may be hard to judge where full regen was reached and where handbrake engagement began.
That was why i had the picture in my mind that pulling on the handbrake when approaching an intersection may result in some physical brake engagement resulting in the car going more sideways than was intended. More so if it was wet weather.

Another thought, not sure if all cars are the same but none of the cars i own light up the brake lights when the hand brake is engaged. Not difficult to add if your car has the handbrake switch that lights a dash light to remind the driver the handbrake is on.

Whilst on the subject of handbrakes. Last night I had to disconnect mine to enable me to remove the petrol tank. And yes, i did end up with petrol all over me even though the tank had been pumped dry. The electric fuel pump doesn't quite get all the petrol out.

At least that is the last time the car will have any petrol in it other than maybe transporting a can of petrol for a chainsaw, a lawn mower or rescuing a stranded ICE driver.

[Astro]

Originally Posted by MPaulHolmes

I was reading the MIT license (I always wanted to go there, but the 1.2 gpa wouldn't allow it. lol). What if someone changes a little of the code? Are they then forced to include a message to everyone that others can use their code however they want? What if I want others to change the code and maybe keep it all sneaky and hidden if they feel like it, or shout it to the rooftops each line they typed if that's what they want? Reading about licenses is giving me an Office Space style case of the mondays...

I thought that the copyright and licensing stuff was to stop someone taking what you made and claiming it as their own. And then selling the product commercially for a fortune.
If you are not fussed on what people do with the design then does it really need any sort of licensing or copyright statements?
Of course i am totally uninformed when it comes to this stuff.
Maybe there is somebody reading this thread that has had to do this copyright/licensing stuff before and can give you a cheat sheet.