# Should I attempt to build a Brushless controller?



## ken will (Dec 19, 2009)

See how simple they are! they are just 3 brushed DC controllers that fire at the right time.
The hall sensors tell you where the rotor is and then you just send some power to the appropriate coil.

I hope you know how to program an Arduino, or other Microprocessor

.
.


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## strantor (Sep 4, 2011)

I don't know your sense of humor, but I sense you are being facetious. In case you're not, that's an oversimplified block diagram and there's actually a lot more to it than that. 

Funny you should mention it, but in the beginning, when I was planning just a brushed DC controller, I was planning on using my arduino. buf for this, I think the arduino is underequipped. If I procede with this project, I will likely be getting better suited microcontroller products from microchip.


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## ken will (Dec 19, 2009)

I Had the feeling that you like a lot of the Electrical Engineers that I know can get so tied up in the details, that they don't see the big picture.

So, I posted a "big picture" easy to get a feel for, block diagram.

If you concentrate on one section at a time you don't get overwhelmed.

There are plenty of web sites to help with the power section, which is just 3 PWM drivers.

The microprocessor section can be built with discrete components.
I mentioned the Arduino, because it is the flavor of the month. Amazon.com has stacks of books relating to the Arduino.

Use what ever processor you feel most comfortable with.

Just basic speed control is simple!

Which options to use can get distracting.
Do you want to monitor battery voltage and current?
Do you want to motor battery voltage and current?
Controller temperature
Motor temperature
RPM

What do you want to do with this info?
When one of the parameters go out of spec do want to shut down completely, or throttle back a little?

How are you going to let the operator know what is going on?
Leds, or USB cable to their laptop or wireless to their BlackBerry?

In this day and age it has to be easily and safely programmable by an inexperienced operator.


So, Yes it can be complex, confusing, and scary.
But, if you break it up into little chunks, you can make a great controller.

And most important: ask the people here what they would want in a controller!!


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## piotrsko (Dec 9, 2007)

ken will said:


> And most important: ask the people here what they would want in a controller!!


I wouldn't do THAT, asking 20 people here will get you a hundred different and hotly debated answers.


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## Woodsmith (Jun 5, 2008)

I would say it is worth having a go.

Some people will say it is hard because they find it hard to do themseves but that doesn't count for everyone.

I wouldn't do it because I don't know or understand enough about electronics, beyond the big block diagrams, but if you do and feel confident then theyer ethere is little to lose and a lot to learn and gain if you are sucessful.


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## ken will (Dec 19, 2009)

You might start with a designer kit like this. $495
http://www.pmdcorp.com/news/press.cfm?ART=43

This on looks like a very complete kit $385
http://parts.digikey.com/1/parts/1700658-ext-board-motor-control-lpc2900-om11025.html

Here is a list of more motor kits from digikey.

4 or 5 hundred $ sounds like a lot but, Knowledge is strength.


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## major (Apr 4, 2008)

Hi stran,

You should decide what you want to do. Build a DIY EV or build a motor controller. This forum is a good place to learn about the EV. For the motor controller, maybe look elsewhere. http://tech.groups.yahoo.com/group/osmc/ I monitor OSMC. I don't post much. Looks like a lot of guys start, few finish up with working units. I'm sure there are support groups on other forums as well. Endless Sphere comes to mind. http://endless-sphere.com/forums/ 

Regards,

major


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## strantor (Sep 4, 2011)

ken will said:


> I Had the feeling that you like a lot of the Electrical Engineers that I know can get so tied up in the details, that they don't see the big picture.
> 
> So, I posted a "big picture" easy to get a feel for, block diagram.
> 
> ...


I'm most familiar with Arduino, and I find it easy. I would love to use it, but I have been cautioned by more experienced guys on my electronics forum that it's too slow to catch things like potentially detrimental overcurrent situations. Looks like I'm finally going to have to get my hands dirty with microchip PIC devices; I have been putting it off for a long time. I really don't want to experience 2 different steep learning curves in the same project, but I also dont want to design my whole project around a technology that might be insufficient.


ken will said:


> Just basic speed control is simple!
> 
> Which options to use can get distracting.
> Do you want to monitor battery voltage and current?
> ...


all of the above


ken will said:


> What do you want to do with this info?
> When one of the parameters go out of spec do want to shut down completely, or throttle back a little?


for a little bit of error, just throttle back; for a lot, shut down and give alarm. Is that what you would expect from a commercial controller?


ken will said:


> How are you going to let the operator know what is going on?
> Leds, or USB cable to their laptop or wireless to their BlackBerry?
> 
> In this day and age it has to be easily and safely programmable by an inexperienced operator.


Ultimately I thought it would be pretty cool to keep the software on the controller, in the form of a web page. Just like when you configure your home router, you plug a RJ45 connector into it and type in an IP address, and configuration come up. But I have much too much to learn before I can realize that dream. for now it will be an LCD, and I will have to make adjustments via manipulating the code.


ken will said:


> So, Yes it can be complex, confusing, and scary.
> But, if you break it up into little chunks, you can make a great controller.
> 
> And most important: ask the people here what they would want in a controller!!


http://www.diyelectriccar.com/forums/showthread.php/best-controller-and-whyi-62972.html



ken will said:


> You might start with a designer kit like this. $495
> http://www.pmdcorp.com/news/press.cfm?ART=43
> 
> This on looks like a very complete kit $385
> ...


Thanks. Those designer kits look pretty sleek, but I would need to modify them to run the big motor (10A max on the first one). Also I would feel like I was missing out on a lot of good learning opportunities considering most of the work is already done for me.



major said:


> Hi stran,
> 
> You should decide what you want to do. Build a DIY EV or build a motor controller. This forum is a good place to learn about the EV. For the motor controller, maybe look elsewhere. http://tech.groups.yahoo.com/group/osmc/ I monitor OSMC. I don't post much. Looks like a lot of guys start, few finish up with working units. I'm sure there are support groups on other forums as well. Endless Sphere comes to mind. http://endless-sphere.com/forums/
> 
> ...


I want to build a controller. I want to build a controller that people who want to build an EV want to use. That's why I'm here. I can't fully realize what a good EV controller is, or should be, unless I've built an EV. so I'm building an EV (go cart) in tandem with building a controller. I can think of no better way to make sure that all the EV needs are addressed by the controller. 

I also have subscribed to the OSMC newsletter, or whatever they call it, I get the emails. I'm not 100% sure how that OSMC thing works; I think you order the board from them, then you put the parts together and go from there. I'm not to keen on their rule of making my design open source so I'm starting from scratch with my own design. And I have an account on Endless-sphere.com under the same name. other forums I am a member of : forum.allaboutcircuits.com (where I hang my hat) and www.electro-tech-online.com


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## Salty9 (Jul 13, 2009)

Have you checked http://www.diyelectriccar.com/forums/showthread.php/diy-hybrid-brushless-motor-controller-using-23799.html?highlight=alternator?

In it, Tesseract conducts a socratic seminar on building a controller for an alternator which is similar to BLDC motors.


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## aeroscott (Jan 5, 2008)

When I started out on this forum , the very few knew new about controllers and the ones that knew kept it to themselves . Now because of those " few with out a clew " started to smoke silicon we now have a much better understanding of controllers . We are not there yet , but soon . Controllers are the hart and sole of the ev , the more we learn the better we evolve and same for the ev . The power of the igbt / controller can do so much for us , weld , induction melt metal , charge batteries , manage machines etc. Study and ask questions , for everyone's benefit .


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## strantor (Sep 4, 2011)

Salty9 said:


> Have you checked http://www.diyelectriccar.com/forums/showthread.php/diy-hybrid-brushless-motor-controller-using-23799.html?highlight=alternator?
> 
> In it, Tesseract conducts a socratic seminar on building a controller for an alternator which is similar to BLDC motors.


Thanks, that was really helpful!


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## bangerla (Dec 11, 2008)

strantor said:


> I'm most familiar with Arduino, and I find it easy. I would love to use it, but I have been cautioned by more experienced guys on my electronics forum that it's too slow to catch things like potentially detrimental overcurrent situations.


Your microcontroller shouldnt be handling any fast overcurrent situations anyways. This is always best to do with discrete logic and a comparator. This is how "cycle by cycle" current limiting is implemented.


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