Why is the rotor angle and speed multiplied by a gain of 4 in PMSM control?

https://kr.mathworks.com/help/sps/ug/permanent-magnet-synchronous-machine.html

I'm studying for PMSM control, so I refered to this upper link.

I can't understand that the rotor angle and speed from the PMSM block have a gain '4' at the feedback loop.

Answer 1

[Yash]

Hi,

If you observe closely, the rotor speed was "wm" and after multiplication by 4, the speed is labelled as "we". Refer the figure below:

These "wm" and "we" are mechanical speed and electrical speed respectively.

The ratio electrical speed by mechanical speed in a PMSM is equal to the number of pole pairs.

By default, the number of pole pairs is 4 in Simulink PMSM. Refer to the documentation of the PMSM block for more details: Three-phase permanent magnet synchronous machine with sinusoidal or trapezoidal back electromotive force, or five-phase permanent magnet synchronous machine with sinusoidal back electromotive force - Simulink (mathworks.com)

Therefore, the mechanical speed is multiplied by 4 to get the electrical speed. Similar logic has been appiled for the Rotor angle as well.

Hope this helps!

[Esther Kang]

Thank you so much!