Issues/Application of [Observer + PLL (Sensorless)] + Hall Sensor for controlling SVPWM.

[Vincent7]

Hello Everybody,

MCSDK:6.3.0

CubeMX: 6.3.0

Workbench : 6.3.0

Cube IDE : 1.15.0

Power Board : IHM08M1(Rshunt=0.01Ω)

Control Board : NUCLEO-G431RB

Motor : BLDC 26w 24v/8 pole pairs / rpm=4k / rated current=1.8A/hall sensor

Part of the settings from Workbench :

  a) Speed Sensing Selection : Observer +PLL(Sensorless)

  b) Speed Sensing Config / Auxiliary Sensor - Speed Sensor Mode : Hall Sensor

I have some questions about setting the Speed Sensor Mode to Observer + PLL (Sensorless) and using the Hall Sensor as an auxiliary to control SVPWM :

1) My understanding is that at low speeds, the Hall Sensor is used to calculate and read θ_e and control the duty cycle. When the motor reaches medium to high speeds, Observer + PLL (Sensorless) takes over to calculate and read θ_e and control the duty cycle. Is this application or concept correct?

2) When operating at low speeds, how should the relevant API be called in the program? And when the motor reaches medium to high speeds, how should it switch to the corresponding API for Observer + PLL (Sensorless)?

3) When using the Hall Sensor to control SVPWM at low speeds, does the Dead-Time remain the same as the value set in MCSDK (e.g., 850ns)? Or is this something that the user needs to manually adjust?

[Vincent7]

Hello Everybody,

Based on my question, here is my current understanding and the results after my experiments. If there are other approaches or if my understanding is incorrect, please kindly guide me. Thank you.

Response to

Question 1: 

   After consulting a professor, this approach is feasible.

Question 2: 

   Currently, I can switch from open loop to SMO+PLL. However, using the same operation method in Motor Pilot,  when I switch from open loop-V to torque mode, a speed feedback error occurs. I don't know why?

Question 3:

  I'm still trying to understand how to call the Hall Sensor APIs, and I'm not yet sure if I can successfully switch from an SMO+PLL-based approach to using the Hall Sensor. If there are other methods or how to do it, Please guide me, 

Thank You~