Hall Electrical Phase Shift

[Vihaan]

I am referring to the ST document about motor control, it is too complicated a subject to understand and remember. I am trying to understand the hall electrical phase shift as shown below

My understanding of the importance of the phase shift parameter is below, please correct me if i am wrong
The first position as below is the rotor 0 Degree.


When BemfA is at peak it is at 90Deg, the vector sum of all the Bemf is at 90 degree to the rotor position. The Iq shall overlap with the resultant Bemf vector for Max torque. I shall drive my FOC in such a manner. Is it correct? Few clarifications are the Bemf is phase voltage or line voltage i have to consider? What changes i have to make if i consider only line voltage BEMF since the neutral is not available? Can the delay be any angle like 60Deg etc? Please help.
ST document page 94.

 

[Vihaan]

Any help or any links to study about this?

 

[stancecoke]

Any help or any links

There is no generic link from the hallsensor signals to the rotorposition. The hall sensor events depend on the wiring order and the mechanical position of the hallsensors.

It helped me a lot for unterstanding, to turn the thinking around. Just let the motor turn slowly in open loop with a little current like 1A for id and iq = zero. Then the rotor aligns itself to the magnetic field of the coils and you can see which hall event belongs to which angle.

We use this strategy in the self learning function:

EBiCS_Firmware/Src/main.c at a8e19db28f770e812f2ec902553bdaceab8d5c7d · EBiCS/EBiCS_Firmware

Free FOC firmware for Lishui E-Bike-Controllers. Contribute to EBiCS/EBiCS_Firmware development by creating an account on GitHub.

github.com

regards
stancecoke