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Author Topic: Help me understand something about controllers  (Read 227 times)

Mattbastard

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Help me understand something about controllers
« on: September 06, 2017, 09:40:31 AM »

I'm doing a LOT of research regarding motor and controller options.  Turns out using PMAC (brushless DC is the same I think?) you have a bit of programming to the controllers.  Nothing like the brushed motors.  Is this correct?

I'm asking because I've currently got the brushed motor and Alltrax controller.  According to many online resources programming the Alltrax SR is a breeze.  Basically you turn a few dials and move some knobs, maybe tweak the throttle performance a bit and hit the road.  Whereas the brushless motor controllers don't seem that straight forward.  For starters, I can't find any straight forward reference to making a Sevcon Gen4 work with any brushless motor (ME1507 for instance).  In fact, I'm also seeing that you'd need to buy some $300 USB-CAN device to even begin cracking the code. 

Is this basically true?  Now don't get me wrong, I like a challenge, I just like to know what I'm up against before diving in. 

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MrDude_1

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Re: Help me understand something about controllers
« Reply #1 on: September 07, 2017, 08:39:39 AM »

Yes 3 phase controllers can get complex.

On one side, you have glorified RC car controllers that require only the 3 phase wires and they work.
On the other side, you have massive field oriented controllers that have a million settings.

So. How complex do you want it to be? lol.

The best thing you can do is learn how BLDC and PMAC motors work... then how basic controllers work.. then how sensored controllers work. then the concepts behind Field Oriented Control. And finally the ideas behind things like sensor mapping.

once you have all that baseline knowledge, you can then dive into the manuals of whatever controller you want, and then learn their specific proprietary knowledge.... for example, I have no idea about the details of programming a Sevcon, but if you wanted me to make you a controller for a motor from scratch with custom firmware its well within my abilities. So on my zero I would be lost even with what I know.. because I dont know the specific settings for that controller.

So dont worry if you cant get anything straight forward without digging into specific manuals for that model. Its just kind of how it is right now.
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Mattbastard

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Re: Help me understand something about controllers
« Reply #2 on: September 07, 2017, 09:48:34 PM »

Cool, thanks for the feedback.  Looks like I'm back on the fence now whether or not to stay brushed or go brushless with a LOT of work ahead of me. 
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frodus

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Re: Help me understand something about controllers
« Reply #3 on: September 07, 2017, 11:31:47 PM »

I'd just get a Kit with motor and controller already set up for each other. You MIGHT need to do some tweeking, but it'd be things like Throttle type, RPM limits, Voltage limits, etc. The Tuning parameters are the super hard part.

Is this Matt that I'm talking to via email? I think you said you already have the Motor.

Doug S

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Re: Help me understand something about controllers
« Reply #4 on: September 07, 2017, 11:51:36 PM »

Endless sphere (Google it) would probably be a better resource if you're trying to build from scratch.

I'd have to ask why you're doing it, though. If you just want the experience, to learn how it's done, go for it....but if you don't keep it simple, you'll get bogged down in so many details like this that it'll never get done.

If you're trying to build an EV cheaper than you can buy one, that is a possibility. But it's not likely to be a particularly enjoyable or functional ride. It's kind of like building your own computer. You can source the components you want and build it yourself, and there was a time when you could have a pretty wicked machine and save a lot of money by doing that. But it just doesn't really work any more. They've gotten so cheap to buy that assembling one yourself doesn't really save anything -- the only real reason to build one yourself these days is if you're a gamer and want the absolute best components you can get, or if you have very specific needs that aren't satisfied by something OTC. And even then, if you want the portability of a laptop, forget it. No one person has the resources, time or all of the abilities to do that much engineering all by themselves, and if they did, they'd never save any money by doing it.

Not to discourage you, but there is a time in most technologies where they evolve beyond the abilities of even the best of the DIYers.
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Mattbastard

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Re: Help me understand something about controllers
« Reply #5 on: September 08, 2017, 02:53:38 AM »

I'd just get a Kit with motor and controller already set up for each other. You MIGHT need to do some tweeking, but it'd be things like Throttle type, RPM limits, Voltage limits, etc. The Tuning parameters are the super hard part.

Is this Matt that I'm talking to via email? I think you said you already have the Motor.

Yup, that's me.  No motor yet, or controller.  I do have motor and controller but it's the wimpy ones that came in the bike. 

Originally I was going to put in the ME 1507 from Motenergy and a blank Sevcon Gen4 controller at 96V.  That was until recently when I learned just how NOT plug-and-play these BLDC motor/controller combinations are.  Your website came up as a programming option because doing it myself seems a bit over my head.  I can tackle all the fabrication, the programming would stop me dead in my tracks and would have a steep learning curve from what I'm learning.   

I also reached out to Harlan, who gave me some pricing on the Zero motor (very similar to ME1507) and controller, and quote for programming as well but I'd have to bring the bike up to Hollywood for that end of the transaction. 

Ultimately I want to know a combination is technically possible to work together before I spend a few grand.  I really want to do the programming myself to gain a certain sense of accomplishment, but it would be nice to know that someone could come in to save the day if I threw enough cash at them to fix my F#@%-up.   :P
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