sensored BLDC Motor input signal

hi everyone...

I have a 3-phase BLDC motor (24 V) with its dedicated driver. but i wanna make my own driver for the motor. it is sensored bldc motor. I have read some application notes and other kind of sources about controlling sensored BLDC motor and found that it is controled by 6 commutation steps. A fundamental BLDC motor (with 3 coils and 1 pair of poles) need 2 cycles of 6 commutation steps for 1 motor rotation. My BLDC motor has 12 coil, but i don't exactly know how many pairs its pole.
how can i know the number of pole?
with different number of coil and pole, does it need different number of cycle too?

i have checked the signal on the BLDC I/O pins when it's run by its original driver. its I/O pins contain Hall sensor feedback pins and phase pins.

here is the results:



this is signal on the 3 pins which is known as phase pins. it is 24 v pwm signal.





and this is signal on the phase pin too, when it's measured at the same time with the hall sensor pins. 1-3 are phase pins signals (24V), and 6-8 are hall sensor pins signals (5V).


there's different result on the phase pins. could anyone explain?
which one of the signals is input signal to the motor?
it's confusing for me, because i assume that the motor input signal should same as with what the application notes has explained, commutation signal.

anyone help please????
:?



best regards

Re: sensored BLDC Motor signal input

PWM on MOSFET bridge is actually driving input which is controlled by hall sensor output...

so, is it important to know number of pole?

or i just have to give input signal to the motor based on feedback from hall sensor output, no matter how many its pole?

It is important to know number of phases...
and in most of the cases it is 3...

Added after 2 minutes:

U can check ur hall sensor sequence manually...
Just feed in 5v to hall sensor input...
and rotate the motor manually.... u will get the sequence for ur existing motor...

i have given 5v supply dc to the 3 hall effect sensors. and rotate the motor manually.
i got the sequence form for my bldc motor is normal square wave.
but in many application notes, the sequence form is not normal square wave. there are floating areas, like this:

https://obrazki.elektroda.pl/48_1274844402.jpg

so.... it means my bldc motor doesn't need floating area?

what do u mean by floating area???

when the signal voltage like this:

In ur three phase BLDC, there is no common or neutral line....
current enters through one coil and exit through second one.. and third is not carrying anything...
So at a time only two phases are excited and third one is idle....

ok, i think i got the point


i'm so grateful for the information
thanks

Hi friends, Could anybody explain me about 3-phase BLDC motor? What is the input to the motor? Is it a DC or AC motor? If it is a DC motor then why 3- phase?

It is DC motor only... we supply DC for running the motor
we switch the DC in each phase to run the motor...
Phases r for commutation....but DC flows through each winding...