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

[e*clipse]

I don't know about other motors, but the Toyota setup is a 50kOhm thermistor. There's a 50kOhm resistor and a 5V reference on the driver board I sent. Anyway, it's set up for an A/D converter.

- E*clipse

Originally Posted by MPaulHolmes

By the way how does the motor temperature thing work on a standard motor? Is it a thing that goes from off to on, or is it a thermistor, or how the heck does it work? I'm trying to figure out the best interface for the motor temperature. Does it need another A/D channel or is it an ON/OFF?

-Paul

[MPaulHolmes]

Is there a curve anywhere for temperature vs voltage reading? And it's a 50k thermistor? I think microchip recommends to have <= 4.7kOhm impedance on the A/D input. Does that mean I would need an op amp voltage follower to create a lower impedance?

[e*clipse]

Here's a good resource for them; it's better than I can explain..

https://www.digikey.com/Web%20Export...f?redirected=1

One way to address the input impedance issue is to put a small capacitor from signal>ground. The thermistor isn't going to change output very rapidly, and the capacitor will just follow it's output. You don't need to add all the complexity of an op-amp buffer, because the response is so slow.

Also, I just got an e-mail regarding the motor. Same price, and they'll ship it to you for $30. They must have some special discount shipping arrangement. I'm just waiting to hear if it's in as good a condition as the one I have.

- E*clipse

Originally Posted by MPaulHolmes

Is there a curve anywhere for temperature vs voltage reading? And it's a 50k thermistor? I think microchip recommends to have <= 4.7kOhm impedance on the A/D input. Does that mean I would need an op amp voltage follower to create a lower impedance?

[freebeard]

I paid too much! Do they have the big orange cables?

[e*clipse]

Nah! Frankly, I think the higher price is just fine, when the $$$/Watt + gearbox factor is considered. This was just one of those "had to do something" opportunities.

Regarding cables, unfortunately no... I think I'll take up this issue in the MGR thread.

Paul - I got the pics from this one and for some reason the output flanges weren't there. I'll see what they say tomorrow. Since I could use it anyway ( I'm making a spool ) I may just order it and send my complete one to you.

- E*clipse

Originally Posted by freebeard

I paid too much! Do they have the big orange cables?

[MPaulHolmes]

What's the pinout on the board you sent me? I'm working on the code for the change, but am not sure what pin does what.

-Paul

[e*clipse]

Sorry Paul,

Here's a quickee description. I'll post a better (graphical) description tomorrow.
First, you should have the design spark files. I named all the nets with outside connections.

Plug 1 (the SIL plug on the bottom of the board) is the processed sine, cosine, and temperature data for the motor controller and ground/+5V supply for the driver board.
Pin 1 is furthest away from the notch in the corner.

Pin1: Cosine output (this is one of the sin/cosine signals that needs AtoD conversion)
Pin2: +5V supply (from mainboard)
Pin3: Sine output (this is the other signal that needs AtoD conversion
Pin4: Temperature sensor ( setup for the 50kOhm thermistor U3 is the reference)
Pin5: Ground


Plug 5 (the 8 pin plug on top) is the I/O connection to the MGR. There is a ground reference/temperature probe connection for the 3 pin connector on the MGR. The remaining 6 pins match the 6 pin resolver connection on the MGR. These connections are matched pairs that connect to the resolver's driver and sine/cosine outputs.
Pin1 closest to the notch in the corner. Pins are numbered CCW, like an IC)

Pin1: Ground
Pin2: Sine b (half of the sine input coming from the resolver)
Pin3: Cosine b (half of the cosine input coming from the resolver)
Pin4: Sine output A (half of the sine signal that drives the resolver)
Pin5: Sine output B (the other half of the sine signal that drives the resolver)
Pin6: Cosine a (the other half of the cosine input coming from the resolver)
Pin7: Sine a (the other half of the sine input coming from the resolver)
Pin8: Temperature sensor (setup for the MGR's 50kOhm thermistor


Plug 3 is the higher voltage power supply for the driver's amplifier (LM7372) The IC is rated to about 30V. I've tested it at 15V, and it should work fine at 24V.
Pin1 is on the left, closest to the other connectors.

Pin1: +24V
Pin2: Ground

Regarding other holes on the board:
The big holes are provided for anchors to connect to the mainboard. Preferably this will work in that space in between the logic and IGBT driver sections.

The small holes in the lower left corner, opposite the notch are intended for a heat sink for the driver amplifier. So far I've been really amazed to find this to be completely uneccessary. The ground plane heat sink along with the top plane heat sink seem to do fine by themselves.

Hope this helps,

- E*clipse

Originally Posted by MPaulHolmes

What's the pinout on the board you sent me? I'm working on the code for the change, but am not sure what pin does what.

-Paul

[MPaulHolmes]

Thanks! Sorry for all that typing I just made you do. I do have the designspark files. my bad. I completely forgot that you sent them to me.

[P-hack]

Sorry, this sounds like another semi-private discussion, what board?

edit: guessing it is a carryover from the hotrod resolver discussions? Hi frequency sine wave thingie?

If anyone else is lost, 3 coils and an elliptical rotor, determines shaft electrical angle (don't remove the resolver from the case, it is calibrated at the factory), using techniques akin to sensorless position detection.

edit 2: info about the chip used in the prius http://www.tamagawa-seiki.com/pdf/do...FT20110708.pdf

http://www.turbo-electric.com/upload...0resolver).pdf

http://web.archive.org/web/200503110...singlsynm.html

$10 chip: http://www.ebay.com/itm/AU6802N1-Enc...item58a1313133
edit3: I see eclipse identified it 600 posts ago, LOL!

https://www.youtube.com/watch?v=c2BneFL1A2E

[P-hack]

Just curious, were the pros/cons of sensorless "bldc" vs resolver discussed? I assume toyota knows what they are doing, but it isn't immediately obvious how a second set of coils and rotor and circuitry actually help.


edit: did my own homework, got it. more accurate, esp at high loads.