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Topic: Arduino controlled 72v 350a DC Motor (Read 4024 times) previous topic - next topic

briansterling81


Just floating the idea out there for you big brains.  links take you to the corresponding parts.

I've built some EV motorcycles and I've always used either an Alltrax or Curtis controller meant for golf carts and the such.  I'm going to integrate a TFT interface for readouts and I'd like to take full advantage of any functions that could also be handled by the Mega 2560 board.  My question is if anyone knows of any successful project that can control my purchased high voltage high amp motor in an EV?  I ran into this instrucatble where he made a MOSFET controller from scratch which is great but I was hoping there was a middle ground between that and just buying a controller out-right.  These controllers hover around $400-$650 so anything below would be gravy. 

Concerns.
Heat - I doubt a shield of sorts would be smart
Control - I use a 0-5K Ohm Magura Throttle
Features possibly giving up - Throttle ramp up profiles, 1/2 speed reverse, battery over voltage cut-back, thermal shutdown

Below is a rough draft of controls I plan to implement. 

CrossRoads

With that much power, go the smarter route & use a commercial controller that you can interface to.
P=IV = 350*72 = 25,200W.
Use Mega to control the controller, do monitoring & stuff.
Map databases are huge, 16 MHz 8-bit microcontroller might be insufficient for that.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

briansterling81

I figured it would be smarter to go the pre purchased route. I just wanted to explore the option since these controllers are pretty simple devices on the whole and terribly expensive.  I was looking for a MOSFET rail system to have a half-way point for the two options and just have the Mega control the PWM throttle.

For the GPS I only need my local gps library since I won't be touring with its limited range of only 60 miles. Do you think it's a workable option then?

CrossRoads

Probably. Use a voltage divider to measure the voltage, get speed from GPS,  health is whatever you define from conglomeration of inputs, same for log, settings.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

briansterling81

I guess I could've been more descriptive on that, sorry.

Health - Takes you to another menu where you can see individual voltage for each 12v 45ah battery
Log - Figured I'd have a list of recent warnings and status updates with timestamps
Settings - screen brightness, display sleep, Turn on/off GPS, change PIN Password, and hopefully some controller settings if I can succeed in replacing the need for a dedicated controller
GPS - Just a local library of my general vicinity.  Maybe some other features I have yet to realize.

I'm going to keep researching because I'm sure there's a way to keep the lion-share load/heat away from the board and just have a 0-5K Ohm throttle control the motor.  Are there any shields or accessories you would recommend for my general direction?  I've already figured I need a Relay Shield to control my headlight, blinkers, tail-light, and horn.

Also have a battery health menu.

I really appreciate your advice.

CrossRoads

No, I think you're in custom land on this one, especially on battery monitoring. There's been lots of discussion on how to do that. I've favored individual relays that can switch the connection points, like having a handheld meter that you move from battery to battery.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

MarkT


I figured it would be smarter to go the pre purchased route. I just wanted to explore the option since these controllers are pretty simple devices on the whole and terribly expensive.  I was looking for a MOSFET rail system to have a half-way point for the two options and just have the Mega control the PWM throttle.


Have you checked the latest stuff at OSMC? There might be something relevant?
https://groups.yahoo.com/neo/groups/osmc/info
http://www.robotpower.com/osmc_info/
And commercial options include Roboteq: http://www.roboteq.com/index.php
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

briansterling81

I will check those out in the morning. I'm sure there are some useful knowledge there. Thank you very much for the information.

briansterling81

#8
May 15, 2014, 06:48 pm Last Edit: May 15, 2014, 06:54 pm by briansterling81 Reason: 1
Hey guys,

I've asked to join the group but the OSMC site doesn't exist anymore.  The group may have some good info though.

I got bored waiting on some of my components and decided to do a sketch up of my system.  I know this stuff is mainly geared toward EV builders and not Arduino hobbyist but I figured you guys may have some input.  As of now I'm trying to piece out what hardware I need and where.



And here's a link to the Larger version

I'm sure there are tons of mistakes but it's a rough draft.

Brian




MarkT

[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

briansterling81

I wouldn't say wow just yet. I've built one of these before so the HV system isn't to much an issue but Arduino is new territory for me.  Any components you guys see missing , please throw me a line.

michinyon

The speed from a gps device is not really going to be reliable enough for motor control.  It works ok when you are cruising along,  performs poorly when you stop and start.

michinyon

The only odd thing I see on your diagram,  is the "low current fuse",   which appears to be in the high current path.

If that is supposed to be a low current fuse to protect the low voltage electronics,  you might need to move it about an inch to the left.

briansterling81

--The GPS device wasn't going to be involved with any motor control.  It's just going to be an feature loaded with local maps for convenience.  Would be nice to map my routes as well.  CAN I use a gps with motor control?  I'm not sure what you're getting at?

-- Thanks for pointing out that fuse.  I updated my diagram and neglected to change a few small things around. 

As someone who hasn't received any of these parts yet I'm beyond beginner at this point.  With an LCD shield, a relay module, and possibly a GPS shield I'm not sure how these all physically connect.  I see some shields have pin passthroughs but does that mean anything stacked on top of that pin shares it?  How does the arduino recognize different data on the same pin?  I'm missing a fundamental concept.

Thanks guys,

Brian

briansterling81


It also just occurred to me that I may be able to use the Arduino as my BMS as well.

If the board is constantly measuring the voltage of each individual battery then it stands to reason that I could use that data to close the relays on the 12v individual chargers and shut off when reaching a certain voltage to prevent over charging.  I'd have to upgrade to at least the 8 channel relay but I think it's doable.  The data is already being collected, might as well use it for more than just a display.  Thoughts?

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