Hello Everyone! Newbee here!

I am trying to understand the proper relationship between a PMSM motor’s back EMF and the maximum speed it can achieve.

I have been browsing the net for an answer and not able to find a satisfactory one

Looking at this article :

They say that no load speed (Wnl)is (Kv * Vsupply) → Is this formula correct?

Where Kv is the motor constant in RPM/Vp.

Now in the context of FOC, generally FOC uses space vector modulation for the PWM generation, so shouldn’t Vsupply be (Vsupply/sqrt(3)) ? Can someone please clarify this for me.

Looking at another thread,

Here they are indeed dividing the DC bus by sqrt(3), but the back EMF is in mV/Hz !!!

So which is the correct equation?

If the maximum speed of the motor is not given on the name plate , can we approximate it using the above formula?

For analysis , i have a TecnikM-2310P motor with the following specifications:

Assuming a DC bus of 30v, and Ke of 4.46Vp per 1000 RPM, can we estimate the no load maximum speed to be (30/1.732) * (1/(4.64/1000)) , which comes to 3733 RPM?

Thanks,

Arun