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

[a8ksh4]

Interesting post on how to model the fields, currents, voltages in a brushless motor:

Evolution of Segue:

[e*clipse]

Originally Posted by cts_casemod

Ill give it a try mailing Dave and asking if he could supply some of that stuff he shows on the video. I would not be surprised if he already had al algorithm
to use with texas instaspin libraries. That would make your work significantly easier.

Thank you very much!

I am downloading all the lecture info and lab excersises and animations about the Prius motor - there might be an equation with some #'s there. In my case, I'll probably have to change them a bit (it's not exactly the prius motor, it's an MGR with very similar specs)

It's a goldmine of good info - and really icing on the cake that he uses the same motor for a demo!

BTW, for anyone using ANY motor (not just FOC stuff) here is a quick link to the supplimentary info he gives with the lectures. The lectures are very helpful.
TI E2E Community

- E*clipse

[freebeard]

Originally Posted by P-hack

You also hijacked an induction motor thread.

Which thread is that? I get so confused. This thread is AC FOC, which I originally encountered as described as Polyphase DC. Then there is Open ReVolt: open source DC motor controller - Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com, which is stubbed off of Fossil Free Fuel but not available at the Main Menu. And the Toyota MGR thread.

Originally Posted by cts_casemod

Ill give it a try mailing Dave and asking if he could supply some of that stuff he shows on the video.

Dave Wilson? His videos have taught me everything I know, as I posted somewhere back in this thread. It would be great to connect his thinking back to Toyota Synergy Drive OEM components.

e*clipse -- I'm looking at resolvers and sensorless control, and thinking 'why not both?'. Per motor; for redundancy. Then another microcontroller could be a hypervisor. The Space Shuttle used triple redundancy with a 4th computer for oversight.

[e*clipse]

Originally Posted by freebeard

Which thread is that? I get so confused. This thread is AC FOC, which I originally encountered as described as Polyphase DC.

e*clipse -- I'm looking at resolvers and sensorless control, and thinking 'why not both?'. Per motor; for redundancy. Then another microcontroller could be a hypervisor. The Space Shuttle used triple redundancy with a 4th computer for oversight.

Regarding using resolvers and sensorless control - I think it's a good idea. If the sensor output of both the resolver and the current sensors are used for the primary motor controller's anyway, then the sensors' information in its raw form could be sent to another computer as well. Both computers would need to be synchronized so the data matches.

An issue would be how to deal with decision hierarchy. It would be interesting to see how the space shuttle deals with 4 levels of this. I guess I would still want an "E-stop" button and an "Override" button.

For a while I was working on a different throttle; it used a hall-effect sensor that put out a PWM waveform that was proportional to its rotary position. If there was a non-PWM signal (high or low) the microcontroller would put out an error signal. It was a good way to ensure an "all ok" signal. Perhaps something like this could be used for between-computer communication for critical information, rather than analog 5V signals or serial bus communication.

[cts_casemod]

I am actually developing an application using instaspin from texas that uses that concept.

I use the motor encoder to get 200% torque at zero speed and switch to a completely sensorless application when the motor spins fast enough. So far the drawback I've found is that I cannot have a true "coast" state using the sensorless and I am having trouble combining both signals, once the motor is spinning. I also have not been able to test on the vehicle how their sensorless operates at zero speed. At least on bench it seems to work fine.

Right now, sensorless apart I use both the vehicle speed sensor and the motor encoder. I simply ignore the motor encoder below a certain speed and use open loop. Then (generally 100RPM+) I switch to closed loop. This is to avoid encoder noise at low speeds.

Lots of options really... I wonder how low can Paul sensorless operate. Texas is claimed to track down to 1Hz. Idd be queen to test that on a vehicle. Apparently some guys did that on a bus and they actually seem quite happy...

https://

[cts_casemod]

Hi people,

I just installed my pic version of the controller on the car, but for some reason it is lacking quite a bit of power. Do you guys have some C code for space vector modulation I could borrow?

Failed that I am thinking in adding up a 3rd harmonic sine table.

[MPaulHolmes]

Edit: haha, here's a shorter version that does the same thing.
Here's the space vector part of the code:
Va, Vb, and Vc are the 3 phase voltages. pdc1, 2, and 3 are temp variables for the 3 duties. So, at the end you would do

PDC1 = pdc1;
PDC2 = pdc2;
PDC3 = pdc3;

void SpaceVectorModulation() { 
	// I know you can do it faster than this, but I just want it to work.  I'll optimize later.
	// if Vc is smallest of the 3, then do the following...
	if (Vc <= Va && Vc <= Vb) {  // Vc <= Vb <= Va or Vc <= Va <= Vb.  They both have the same
		// Q1 & Q2.
		pdc1 = Va-Vc;
		pdc2 = Vb-Vc;
		pdc3 = 0;
	}
	else if (Va <= Vc && Va <= Vb) { // Va is smallest
		// Q3 & Q4
		pdc1 = 0;
		pdc2 = Vb - Va;
		pdc3 = Vc - Va;
	}
	else if (Vb <= Va && Vb <= Vc) { // Vb is smallest
		// Q5 & Q6
		pdc1 = Va-Vb;
		pdc2 = 0;
		pdc3 = Vc-Vb;
	}	
}

[e*clipse]

YEA!

I got some itty-bitty circuit boards today!

I'll start soldering and post a pic tomorrow.

- E*clipse

[MPaulHolmes]

Awesome!!!!!!!!!! What is your assembly process? Do you have to modify a toaster oven?

[e*clipse]

Originally Posted by MPaulHolmes

Awesome!!!!!!!!!! What is your assembly process? Do you have to modify a toaster oven?

I didn't modify my toaster oven. I've seen things where people added fancy PID controls; I just got a good digital thermometer and documented the response.

I did get one only for soldering - they're pretty cheap anyway - just so whatever weird fumes come from soldering don't infect our food.

For this job, I'll just solder it by hand. Hopefully I'll retain some sanity - this is the tightest board I've ever dealt with. LOL!

Here's a pic of the new resolver board, with some other stuff to reference size.



That's my dog's tooth. It was kicked out by my wife's horse when he was bothering her.