Sensorless three phase brushless DC motor drive simulation problem

Hi, i am building a simulink model of Sensorless brushless DC motor drive based on six-step communication, basically i use the zero-crossing detection first, and connect it to a state flow chart which states six step of the communiction logical, but i just can not get the back emf right, and there is no difference between three phase, i wonder what is wrong here, the sate flow and bemf on attachment, thank you!

[Shivam Gothi]

Hello @Juncheng,

If possible, can you please provide the simulink model? This will assist in diagnosing the issue you're experiencing and recommending potential solutions to address it.

[KrishnaKumar]

You could refer to this example for understanding and implementation : Sensorless Speed Control of BLDC Motor Using Six-Step Commutation - MATLAB & Simulink

Answer 1

[Joel Van Sickel]

please start with this example if you are having trouble: https://www.mathworks.com/help/sps/ug/bldc-sensorless-control.html