1
\$\begingroup\$

I have this BLDC hub wheel motor: https://www.alibaba.com/product-detail/Low-Speed-Big-Torque-500W-13_1601107514377.html?spm=a2756.trade-carp.valid-supplier.3.2a913192a4Sp7y

Which I control with this motor controller: https://www.act-motor.com/brushless-dc-motor-driver-bldc-8015a-product/

I have the following information about the BLDC:

  • Voltage: 48V
  • Velocity: 14km/h
  • Gearing: 5:1
  • Number of ticks per revolution from the controller: 150
  • Hall-sensors: 120 deg.

The motor controller uses only hall-sensors as feedback and I assume it is using simple six-step / trapezoidal commutation.

The slowest speed i can get the motor to run is 0.1 m/s (approx. 0.1 RPS), before the motor starts getting uneven rotations.

Now the question is is it possible to get this motor to rotate slower if I am using another motor controller, without mounting a encoder as feedback?

Will FOC do me any good when only using hall-sensors, and is it even possible?

What is actually determining what the lowest speed of the motor is, is there some physical limits that can be estimated?

\$\endgroup\$

1 Answer 1

Reset to default
1
\$\begingroup\$

You could control the motor like we do it with stepper motors, then you get it more smooth. But you will have always this cogging torque, which is present because of the magnets and the iron cores of each coil. If you move the wheel per hand, you can feel this force.

To use Hall-sensors is the smoothest method you can get with BLDC motors. If you use this Hall-sensor feedback and drive the coils like a stepper-motor with micro-stepping, you could increase the smoothness. Possibly you could compensate the locking force somehow. But I don't know a BLDC-driver available on the market which is doing it like this.

The most driver I know, want to get a analog signal and with it they know the speed they have to drive, but with the cheap driver you get a low resolution.

\$\endgroup\$
2
  • 1
    \$\begingroup\$ I believe what you're referring to by "locking torque" is what's called cogging torque. \$\endgroup\$ Commented Mar 30 at 23:56
  • \$\begingroup\$ @Hearth - Right. Thank you for the clarification. \$\endgroup\$ Commented Mar 31 at 0:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.