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

[e*clipse]

Originally Posted by P-hack

I appreciate the wye confirmation, but otherwise it isn't making a lot of sense to me.

That's fine. I'm done. Goodbye.

- E*clipse

[P-hack]

the chevy volt pack comes with liquid cooling, and is lighter per volt. a 650v 45ah chevy volt pack will weigh 125 lbs more than your leaf pack @ 360v @ 60ah, and *should* be 300kw capable (more like 1/2 a megawatt). That is about the best 125lb investment you can make, no? I mean you have 400lbs of motor, 800lbs of battery is quite appropriate, especially if you get the voltage rating you need to drive them. Heck I'd be tempted to keep going if it pans out into more useable motor power.

If you were content w/4x50kw then delta and leaf pack makes sense, otherwise this looks like the best pairing. And I can't really understand the objections so far, they sound like idiosyncratic, if not unnecessary, requirements. But even the ornl guys don't fully understand the observed behavior of the boost converter, that sounds like a whole lot of variable on top of a lot of other variables, to get 300kw out of a pack that really doesn't want to give 300kw, and motors that might be in the same boat, that come pre-packaged with zero gearing options.

So, yah, take a step back and re-think it a little bit. A pretty controller pcb (which will make an imbalanced capacitor load) and an arbitrary 3000lb limit aren't good requirements, not if 3125lbs will get you another 100kw and eliminate the boost converter.

[MPaulHolmes]

thingstodo, that is very cool! Do you know if it works on the evil horrible "it's going in the garbage soon" iphone? haha. That's the one I have been cursed with. I like how it shows 2 pictures, and also your voice is very easy to hear. It really didn't pick up the noise. You know, I have my very first prototype DC controller (maybe it was my 2nd). It used a heavy duty copper heat spreader. It would need a control board mounted to it. Since your controller failed, to get it to work again, you might have to replace the ten 22Ohm gate resistors (they sometimes crack when there has been a failure) and replace the MIC4451. And possibly the hcpl4504 with a new hcpl4506. Everything else should be OK. I can send you that controller for you to keep. It should work fine. I've never used it though. What's the cheapest shipping way to you? I don't mind paying for shipping. You are doing so much to help in the development, and I am so "thankful" (thanksgiving shout-out).

As for the boosting, where is the 3x current coming from? I have 2 intended uses in mind for the super cheapo AC TO-247 controller with boosting. First, I just wanted to allow higher RPM under load. I have a 200amp 300uH inductor, and my simulations seemed to show that things stay under relative control in that situation. There is a ton of capacitance (to keep things cheap, I am using a bunch of 450v electrolytic caps. heck it worked for the 500amp controller), which I hope will allow for a dual use as a solar MPPT/ 3 phase grid tie. And if you don't want to go to jail, you could instead use it as a MPPT/ 3 phase "not grid tie" sort of thing. I bet there are people who would want 3 phase power at their house, and who have maybe 12 lead acid batteries laying around. Well, maybe there aren't but I'm going to pretend that.

[P-hack]

Originally Posted by MPaulHolmes

As for the boosting, where is the 3x current coming from?

looking at the phase current (I've modeled it here as 100a peak/phase) being fed through the inverter switches, you have 1 output switch (diode) on the boost converter that has to feed all of them, and it toggles between 0 amps and about 2x the output current (50% duty cycle), with the capacitor filling in the gaps, plus large voltage switching. So it is really 3x an inverter switch plus 6x the peak capacity if you really want to push it. Similar story for the lower switch, turns on at pack voltage or higher, turns off at boost current. boost converters have really noisy output.

an inverter switch sees about 32 amps average here, while the simulated boost switch is running at about 96 amps average. It seems like that would severely limit what a controller is capable of if it is an integral part using identical switches.

[MPaulHolmes]

Oh I had been thinking of it as "the black box of the 3 phase part" was sucking a constant 100 amps from the capacitor bank (I wasn't thinking about phase current) at a voltage V. So, I would have to provide 200 amps on the input side at 1/2 the voltage. So, I have 2 high side and 2 low side switches for the bidirectional boost, figuring that my goal was to just turn 150v at 200amp in batteries into 300v at the capacitor bank at 100amp into the 3 phase part.

[e*clipse]

Paul,

Notice the circuit has no capacitor and no inductor. There's no energy storage capability in that circuit.

A boost converter stores energy in the inductor in one part of it's operating cycle, then dumps that energy to the capacitor in the second stage. I've never seen an inductorless or capacitorless boost converter.

I doubt an oversimplification to that level is going to provide much usable information. The waveforms are completely different from how a real boost converter works.

- E*clipse

[P-hack]

Originally Posted by e*clipse

Notice the circuit has no capacitor and no inductor. There's no energy storage capability in that circuit.

it is used to model the current ratio of the inverter switches vs the boost converter switch. The storage is irrelevant in this example, as a capacitor blocks dc. Using sinewave currents to model the motor windings is just a good approximation. If your motor currents aren't reasonably sinusoidal, then you are doing something wrong.

The only thing a capacitor would do here (if it is large enough) is stabilize the dc-link voltage at about 100v, the D1 current is still going to be about 3x what an inverter switch would see on average.

Sometimes it helps to break down a problem into it's component parts for analysis though. Designing a whole car in ltspice can be challenging, I can't even do 3 sine current sources in wye (though I wonder if anyone can), but as long as the phase currents are right, no matter for our switch sizing purposes.

If you are wondering what the waveforms look like for a typical boost converter (with downstream storage), I attempted to model pauls 50 lb ch-200 a bit here. output is again about 100v (108) and load current is also, so this would drive the hypothetical motor in the previous diagram. These particular diodes are having lots of recovery issues.

[P-hack]

fyi, the grid tie stuff is also interesting, and speaking of no storage and two phase motors (and line power):
http://www.iraj.in/journal/journal_f...1756246-49.pdf

[thingstodo]

Originally Posted by thingstodo

Update for Nov 22

DC Motor rotation re-test after equipment moved around and re-assembled in my garage

https://youtu.be/K9JOKahTosM

The video format is a bit different. It uses Google Hangouts live to window 3 camera views.

I'm not sure I like it - what do you think?

Here is a video of the AC Motor rotation test after moving around the equipment

https://youtu.be/as03sdIJNZs

Same new format - no comments so far.

[MPaulHolmes]

I've been updating the software more, so that all the optional variables are in the normal nice format, like real life actual amps (with 1 decimal) and real life volts, and also % of voltage being used, etc.. 16 variables to choose from (0, 1, 2, ..., or all 16). And as you suggested, the 1kHz timer is one of the 16, so you can know what time things are actually happening. I should get it tested and sent over to you hopefully tomorrow. And when you mentioned the csv format or whatever it was called, I looked that up, and just changed it so the output format would be CSV. No sense forcing people to cut and paste into excel. Here's the list of variables:

	// bit 15 set: display counter1ms
	// Bit 15 set: display Id
	// bit 14 set: display Iq
	// Bit 13 set: display IdRef
	// bit 12 set: display IqRef
	// Bit 11 set: display Vd
	// bit 10 set: display Vq
	// Bit 9 set: display Ia
	// bit 8 set: display Ib
	// bit 7 set: display Ic
	// Bit 6 set: display Va
	// bit 5 set: display Vb
	// bit 4 set: display Vc
	// Bit 3 set: display rawThrottle
	// bit 2 set: display normalizedThrottle
	// Bit 1 set: display temperature
	// bit 0 set: display slipSpeedRPM
	// Bit  3 set: display electricalSpeedRPM
	// bit  2 set: display mechanicalSpeedRPM
	// Bit  1 set: display batteryCurrent
	// bit  0 set: display % of voltage being used.  Ratio of radius of <Vd,Vq> to Total voltage.

BAHAHAHA. I forgot to check that there were 16 of them. hahaha. OK, um... I need to work out that little detail.