Brushless design Questions

[Hell-e-Guy]

Hi,
I am designing a brushless controller and have a few questions for you experienced guys:

1- How do you measure the 30deg from BEMF detection to excitation of the next step? do you measure the last 60 deg and divide by 2, or, do you measure time for 360 deg then divide by 12 and use this 30 deg time for the next 360 deg...

2- do you modulate both high side and low side FET's ?

3- do you mask BEMF polling during PWM off time ? If so, do you also mask polling during the beginning of the PWM ON time to avoid glitches?

Hell-e

[Hell-e-Guy]

anyone???

[quax]

Hi Hell-e,

there is a complete discussion about the brushless topic:
http://www.rcgroups.com/forums/showthread.php?t=200567

Your questions are handled there.

Regards

quax

[Aethertek]

http://users.pandora.be/educypedia/electronics/motorBrushless.htm
http://www.electronics-ee.com/Electronics/Circuits/Electrical_motor.htm

Info Here... some useful...

[Hell-e-Guy]

Thanks Guys,
Got my bread board working! Its now turning different motors from 750kV to 5200kV
better then my Jeti BL ESC. Less Current to get the same RPM.
I am now working on modulating both high side and low side mosfets, and using the built in dead band generator to modulate a third mosfet to overcome the intrinsic body diode forward voltage drop.

Will keep you posted...