I run onto some instructables regarding bldc motor control over arduino. Am not much into arduino stuff but for test this could be better and far cheaper solution:
Question: If i upscale this design (+coolers etc. ) can this be used for higher powers ? Let's say in range from 200 - 500W.
I have to start on this project but am limited with budget and for some basic controller this could do the trick.
salvaged-HD-motor/
That's a lot of material to plow through just to give someone a free answer.
Judging from the parts list, the guy has his head on straight. I think it may be easier to find a brushless motor from an RC car, and don't try to save money by using free hard disk drives that require you to buy a rapid prototyping machine. (RC car brushless motors have sensors; RC plane brushless motors generally don't). As a bonus, RC car motors have trapezoidal back EMF (to my knowledge if it's got a sinusoidal back-EMF then it's a brushless AC motor, but that's kind of a poorly documented gray area).
I didn't read it in enough detail to know how scalable it may be. In general I suspect that the basic concept should work, but I'd do it with FET drivers and individual FETs instead of a bridge driver chip (those things just aren't efficient). If the Arduino is sending out PWM to the transistors for motor throttling, then maybe. There's a lot of detail there beyond "make it bigger", but every puff of smoke will be a learning experience.
If you scale it up, be sure to add hardware shutdown circuits, so if the PWM hangs it will shutdown gracefully
Cheers
Klaus
I just started a design for a customer yesterday. He wanted 12V 5A 60W. However, browsing through Digikey. I found higher power MOSFET to be better
From my design doc: FQP47P06 (P 60V 47A 0.026O) and PSMN015-60PS (N 60V 50A 0.015O). Although we do not need the power capability of these MOSFETS, they have very low on resistance and low power consumptions. At 5A, FQP47P06 draws 0.65W and PSMN015-60PS draws 0.4W.
They are not too expensive either FQP47P06 for $2 and PSMN015 for $1 each.
*-------------- So you are suggesting that i should try to up scale this design to fit my need ?
Yes, they can handle 60V * 50A = 3000W max. Of course, you don't want to push it to the limit.
------------ Am not worry about "external" electronics. Am worry about arduino and PWM. I can make the upscale but will the arduino setup ( as described in instructables ) hold ?
Why not? We PWM the MOSFETS via op amp driver. I am sure arduio can drive op-amp inputs.
------------------------------ Can we hear us per mail ? I can contact you in few days...
At least be careful bout PCB layouts in order to avoid common ground paths which can cause havoc to the low signal side.
Yes, email me and let me know when you did. I don't usually check the gmail account.
http://173.224.223.62/motor
describes what happens in the OFF, FORWARD and BACKWARD states. Be sure to always transition to OFF between FORDWARD and BACKWARD. You don't want both P-CH and N-CH to be ON at the same side.
Bottom of the page is the drafted PCB layout. The op-amp inputs are not yet connected. There is a prototype area for a DIP micro-controller, for example: PIC32MX.
Den tirsdag den 5. august 2014 21.18.04 UTC+2 skrev snipped-for-privacy@gmail.com:
Although we do not need the power capability of these MOSFETS, they have very low on resistance and low power consumptions. At 5A, FQP47P06 draws 0 .65W and PSMN015-60PS draws 0.4W.
r $1 each.
fit
want to push it to the limit.
dd in
drive op-amp inputs.
ail account.
to always transition to OFF between FORDWARD and BACKWARD. You don't want both P-CH and N-CH to be ON at the same side.
what does that have to do with a brushless motor driver?
-Lasse
For a reversible DC motor driver, we need to completely turn off one MOSFET before turning on another, if they are on the same side (the left pair or the right pair in the picture) of the power rails.
Den tirsdag den 5. august 2014 21.34.04 UTC+2 skrev snipped-for-privacy@gmail.com:
I well aware of that, but doesn't have much to do with a brush-less motor driver
and your drawing doesn't make sense, as drawn it won't work, what you call off state doesn't exist and it'll short the supply at every state change
-Lasse
Yes, the op-amp needs to be separated. Driving independent gates.
why use opamps instead of proper drivers?
and for anything more than say 12V supply you'll need something else
-Lasse
Picture updated:
http://173.224.223.62/motor/
It allows for better control of the on and off gate voltage.
Some op-amp output upto 30V or +/- 15V.
Den tirsdag den 5. august 2014 22.54.06 UTC+2 skrev snipped-for-privacy@gmail.com:
dotted lines? what does that mean?
but why? for efficiency you want the FETs hard on or off that what proper drivers are for
sure and more, but that doesn't help when they FETs can't take much more that 12V gate-source
-Lasse
FQP47P06 (60V 47A P-CH) can handle 30V gate-source PSMN015-60PS (60V 50A N-CH) can handle 20V gate-source
Den tirsdag den 5. august 2014 23.48.16 UTC+2 skrev snipped-for-privacy@gmail.com:
abs. max. you shouldn't go there
-Lasse
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