The "torque constant" parameter of PMSM block (Simscape / Electrical / Electromechanical / Permanent Magnet)

Dear Sir/Madam,

I am a customer of MATLAB. I am currently working with PMSM block (Simscape / Electrical / Electromechanical / Permanent Magnet).

I have some problems with parameter "Torque constant", and my questions are:

1. What is the definition of the "Torque constant" parameter?
2. What is the method for identification of this parameter?

If I have a motor specification, how can I fill this parameter to model? For example, the sample pre-defined model (Allied-Motion, part: HMP04_002), has: (in 2021A, Update 7).

• Torque constant in model: 0.0483412016764879
• Torque constant in specifications: 0.1

I find the mis-match point between model parameter and specification about Torque constant. Can you explain for me?

The link of specifications (page 8): HeiMotion_Premium_HMP04_20170507scrn.pdf (alliedmotion.com)

3. The unit of torque constant: Nm/Apeak or Nm/Arms?

I would like to hear your opinion. Thank you very much.

Best regards,

Answer 1

[Sanjana]

Hi Hoa,

I understand that you are facing an issue with pre-defined parameterization of the “PMSM” block in Simscape.

“Torque Constant” parameter of the “PMSM” block, is the peak torque induced by the per-unit current of each of the phase.

The reason for the mis-match between the “Allied-Motion HMP04_002” pre-defined parameterization of the “Standard PMSM” block and the specifications shared by you for the “Allied-Motion HMP04_002 PMSM servo motor”, is because PMSM Servo Motors are optimized for high-performance motion control applications requiring precise position, speed, and torque control, while Standard PMSM Motors are designed for general-purpose applications with a focus on high torque, efficiency, and speed control.

The pre-defined parameterization can be edited by double-clicking the “PMSM block” and editing the “Torque Constant” Parameter under the “main” section in “Block-Parameters”.

Below is the screenshot, for editing the “Torque Constant” parameter,

As per the official documentation, the unit for the “Torque Constant” is “N*m/Apeak”.

Please refer to the following link, for further information,

https://www.mathworks.com/help/sps/ref/pmsm.html

https://www.mathworks.com/help/sps/ref/pmsm.html

Hope this helps!

Regards,

Sanjana