I'm building an electric bike from scratch with arduino and open hardware tools. Unfortunately, I'm not an expert on brushless motor controller. I've found some help on instructable (BLDC-Motor-Control-with-Arduino-salvaged-HD-motor) and some IC's from farnell (DRV8332, L6234).
Is there anybody that know what is the simple (and best) way to interface a motor with those specifications? - 3 phases - 250W - 36V, 3-9A 12A peak, - 190RPM max, - Hall sensor
( see Q-F-85SX-Specification.pdf from google)
Ideally I would like to use arduino to control the driver.
You have been focusing on the power drive part, while important, the real challenge is the software functions to actually realise a variable speed brushless controller. I have seen AVR application notes in the past somewhere using a AVR to control a brushless motor and it's not a trivial task. Start-up timing, ramping, etc are critical elements of the control algorithm. So while I'm sure it can be done, It would be a very challenging effort to get it working in my opinion.
If I was building such a project I would consider using one of the available radio control brushless motor controllers that interface to a system as a simple servo. They are very cost effective for their size and having a proven design might get you off to a better start.
This is a really good idea, nevertheless it seems that controller for ebike motor specification (36V 8A 190RPM with Hall sensor) doesn't exist...
You certainly would have to do a more extensive search for one compatible to your voltage/current needs. Most are now made in asia and marketed by many dealers.
Using hall effect sensors for feedback to the controller is an older tech not as popular these days. Most current designs use feedback based on detecting counter emf pulses developed in the motor winding themselves. Just because your motor may have embedded hall effect sensors does not mean you have to utilize them if you use a sensor-less motor controller.
Good and yes read any and all documentation before purchasing. Most speed controller tend to have a safety startup procedure to insure they don't power up trying to drive the motor. Most use an 'arming' sequence like servo control to 100%, then servo to 0% then issue desired speed commands. And having a speed controller rated higher then your normal current is better then using it right at it's maximum ratings. 25-30 amp controller sound correct for your 12 amp motor.
And having a speed controller rated higher then your normal current is better then using it right at it's maximum ratings. 25-30 amp controller sound correct for your 12 amp motor.
What about the protection against the motor damage, if the motor support 15A peak it should burn at 25A?
Check the specific operating manual for the controllers, they may list protections and how they are set=up. I'm not sure many or most have over-current protections. You first line of protection is fuses on either the main battery power or the three motor drive windings as at that power level I would never depend on just automatic current limiting alone.
thanks a lot for you great help. I will order one Phoenix and playing with arduino, the servo lib and the bicycle motor and give some feedback in case of some one is interested.
Well for one thing hobby R/C speed controllers are often used for aircraft where size and even more important weight is very important, less = more. Also battery duration for an aircraft might only last for a 10-15 min flight so heat load may not be as demanding as for a bike with much longer battery run time. I really can't give specific advice for you only general information. When I take on a project where I have don't have direct prior experiance, I tend to search out for proven designs rather then try and select the important parts myself.
When I take on a project where I have don't have direct prior experiance, I tend to search out for proven designs rather then try and select the important parts myself.
Thanks for advice, and you're right - it's the reason of my post - but it's hard to get designs for ebike. You can buy hardware from china (and also some from USA) but sharing is not the rule
Yea, the ebike thing is still kind of new in my opinion. Lots of small start-ups and individuals that can't risk or afford to 'share' too much information. What is really needed is an open source project for an ebike. Look what the open source movement did for the Arduino project!
eBikes came out in the 70's, I guess in the grand scheme of things, that is new... You can build them from kits on Ebay. I was going to build one about 10 years ago, but the batteries than were really heavy. Now ( although expensive) the LifePo4 batteries are the key to the eBikes being worthwhile.
Also Richard is correct, there are about a dozen or more forums devoted to eBike construction.
