Go Back   EcoModder Forum > EcoModding > Fossil Fuel Free > Open ReVolt: open source DC motor controller
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 02-19-2009, 02:12 AM   #411 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,822

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,365
Thanked 1,107 Times in 726 Posts
I currently use external ground and 5v as the voltage references for 0 and 1023 (10 bit). I have never tried using the internal 2.56v. Instead of using the HASS Vref, I was planning on doing several samples of Vout from the current sensor when the controller gets turned on, when the current is guaranteed to be 0, and average those Vouts to get a practical Vref. That's what Fran usually does with his controllers that use the LEM current sensors. He said it has worked really well for him.

I ordered some of the Through Hole MLCC caps for noise filtering, and that inductor. I already have some 0805 MLCC's, but in the spirit of keeping this open source, it's probably easier for the general population to solder capacitors that have leads rather than super tiny surface mount components.

I also made a schematic for the hardware current shutdown only. I'll fake the signal from the current sensor, and make sure the output is what it should be. Then I'll do a throttle test circuit, since it's completely new. Simple, but new. Then, I'll add in the temperature, current sensing, and everything with the mosfet driver. Then I'll try it with a single big mosfet/diode pair. Then I'll try it with maybe 4 or something like Motor_Control suggests. That would be a nice round number to be able to drive around with. I'll have 31 mosfets to work with. Then I'll drive around the town with a 144v 400amp controller running at 72v.

Motor_Control, I really appreciate all your suggestions. Thank you!

__________________
kits and boards
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 02-20-2009, 01:05 PM   #412 (permalink)
EcoModder Student
 
esoneson's Avatar
 
Join Date: Nov 2008
Location: Youngsville, NC
Posts: 117
Thanks: 11
Thanked 11 Times in 10 Posts
Motor Overspeed Protection

Paul,

I have not seen anything in this thread about protecting the motor from over-revving. This is a major concern for protecting the investment of your DC motor.

I know that this function could be done external to the controller through a tachometer monitor with relay to the ignition 'run' switch, but couldn't it also be done in the controller?

Maybe this is outside of KISS but seems like the ATMega8 could monitor a tach input signal and perform the power cut-off too.

What do you think?

Eric
__________________
1995 BMW 318i EV in the making
  Reply With Quote
Old 02-20-2009, 01:11 PM   #413 (permalink)
EV test pilot
 
bennelson's Avatar
 
Join Date: Jan 2008
Location: Oconomowoc, WI, USA
Posts: 4,417

Electric Cycle - '81 Kawasaki KZ440
90 day: 334.6 mpg (US)

S10 - '95 Chevy S10
90 day: 30.48 mpg (US)

Electro-Metro - '96 Ben Nelson's "Electro-Metro"
90 day: 129.81 mpg (US)

The Wife's Car - Plug-in Prius - '04 Toyota Prius
90 day: 78.16 mpg (US)
Thanks: 15
Thanked 636 Times in 369 Posts
The real simple answer is just to not hit the GO pedal when the car isn't in gear.

There are a number of different ways to monitor motor speed. I would imagine the various ways to do it output different information - different ranges of voltage, resistance, etc.

I think that motor-speed monitoring might make a good OPTION for the controller. If it's smart enough, and has enough inputs, why not?

However, it would have to be modified for whatever the input is.

I DO think it's outside the KISS method, but maybe a nice option for later.
__________________


300mpg.org Learn how to BUILD YOUR OWN ELECTRIC CAR CHEAP
My YouTube Videos
  Reply With Quote
Old 02-20-2009, 04:05 PM   #414 (permalink)
Master EcoModder
 
Join Date: Jun 2008
Location: London, Ontario
Posts: 1,096

2k2Prot5 - '02 Mazda Protege5
90 day: 33.82 mpg (US)
Thanks: 0
Thanked 11 Times in 8 Posts
The coldfire I'll be working with has a pin that can count pulses via hardware and store the values in a register. When i get to writing up some firmware I'll monitor that every .01 seconds or so with an encoder on the motor shaft. It would be nice to have RPM feedback to make current-limiting decisions as well. Big ol' state-space controller (a step beyond PID - a big step).
  Reply With Quote
Old 02-21-2009, 06:05 AM   #415 (permalink)
EcoModding Lurker
 
Join Date: Jan 2009
Location: Russia
Posts: 39
Thanks: 0
Thanked 0 Times in 0 Posts
Hall cam senosor may be fited to any tooth whil or gear in trnsmition.
  Reply With Quote
Old 02-21-2009, 06:42 AM   #416 (permalink)
learning to be ecominded
 
brihoo2k's Avatar
 
Join Date: Oct 2008
Location: lakeville in
Posts: 33
Thanks: 0
Thanked 0 Times in 0 Posts
I agree with motor control about going off any gear on the transmission only I would probably go with a proximity switch because I'm more familiar with them and Ive seen them used as an encoder. The only thing is is that an encoder is very fragile while a prox is pretty durable. Having speed feedback back going to the controller would turn it into more like a flux vector drive. With a set up like that you could actually turn it into a home made cruise control
__________________
Does the voice in my head bother you?
  Reply With Quote
Old 02-21-2009, 10:15 AM   #417 (permalink)
EcoModding Lurker
 
Join Date: Jan 2009
Location: Russia
Posts: 39
Thanks: 0
Thanked 0 Times in 0 Posts
Cam sensor is auto part and very robast designed for hush envieroment and may be bot anyware. Fully static operation in defference of variable reluctance crank senosr or ABS whil sensors.

Nice animation of cam sensor and datasheet - http://www.melexis.com/Assets/Hall_E...sor__3721.aspx

When any steel part is near of tip of cam sensor it pull to GND his out.


Last edited by motor_control; 02-21-2009 at 10:48 AM..
  Reply With Quote
Old 02-21-2009, 10:46 AM   #418 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,822

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,365
Thanked 1,107 Times in 726 Posts
Quote:
Originally Posted by brihoo2k View Post
Having speed feedback back going to the controller would turn it into more like a flux vector drive. With a set up like that you could actually turn it into a home made cruise control
Fran has made a number of vector drive controllers, and I just talked with him this morning after reading these messages (I love Gmail Chat!). He suggested that you just put a small magnet on the motor shaft, and have a cheap hall effect magnet sensor near by. Here's one that would work:

Hall Effect Magnet Sensor!

It switches off when a magnet is near by. The switching time is like 1.3 millionths of a second, and since the RPM wouldn't be over 10,000 (THAT'S PER MINUTE ! HAHA! MINUTE! SLOW POKE MOTOR!), it becomes pretty easy to figure out RPM, how RPM is changing, how the change in RPM is changing, ... and you can then control RPM by limiting the PWM duty. That sounds fun!

That feature would be an extra $6 though. Not for everyone... Only those with fat bank accounts.

So a CAM sensor isn't a camera sensor? OOps. I thought that was a picture of a camera in motor_control's picture up there. hehe.
__________________
kits and boards

Last edited by MPaulHolmes; 02-21-2009 at 12:11 PM..
  Reply With Quote
Old 02-21-2009, 12:38 PM   #419 (permalink)
EcoModding Lurker
 
Join Date: Jan 2009
Location: Russia
Posts: 39
Thanks: 0
Thanked 0 Times in 0 Posts
CamShaft sensor has biltin magnet and hall sensor and electronic circuit

cam sensor - Google. ??? ???????? ?????????.
  Reply With Quote
Old 02-21-2009, 01:20 PM   #420 (permalink)
PaulH
 
MPaulHolmes's Avatar
 
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
Posts: 3,822

Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
Thanks: 1,365
Thanked 1,107 Times in 726 Posts
Some power board section progress


Non-copper side of capacitor board.


Copper side of capacitor board.


Mosfet/diode board on top of capacitor board, getting ready to drill holes for bus bars.


Oops, let's stop drilling, and make sure we only drill with copper on top, since evidently, copper gets sort of stretchy when it warms up.

__________________
kits and boards
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control MPaulHolmes Fossil Fuel Free 3457 10-03-2019 05:50 PM
Paul & Sabrina's Cheap EV Conversion MPaulHolmes Fossil Fuel Free 542 11-12-2016 10:09 PM
Three Dirt Cheap DIY Electric Cars - Part 5 SVOboy EcoModder Blog Discussion 0 12-12-2008 05:10 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com