How to calculate Stall torque using Flux Motor

Jaime Maraví

Hi, 

I need to calculate the stall torque of a specific motor. I am trying to do it using Flux Motor but can´t find a way to do it. Is there any way to do it? Maybe using Flux instead?

Thanks for your help. 

Jaime

fzidat

Hello Jaime,

 

Are you computing an induction motor ?

 

If yes, then you can make a sine wave test, where you can find the breakdown torque, or you can also make a test model to extract the 1 phase equivalent circuit, we are computing also the whole torque vs slip curve.

 

Regards 

Jaime Maraví

Hi Farid, 

No, I am not computing an induction motor but a PMSM with surface-mounted magnets. 

How can you extract the 1-phase equivalent circuit in Flux Motor?

Regards and thanks very much for your answer. 

Jaime

fzidat

Thanks Jaime!

 

If it is a permanent magnet machine, then you can export it for Flux 2D, and then you can make a computation versur rotor position for a given supply (Ia, -Ib/2, -Ic/2) and then you can plot a static torque, so you can have the maximum torque for a given current supply.

 

For permanent magnet machine, there is no 1 phase equivalent circuit in Flux, you can have the maps of Ld & Lq vs Iq & Iq as well as other quantities.

 

Best regards 

Jaime Maraví

Thanks very much Farid. That´s a great idea. I´ll try it out and get back to you if I get any errors.. 

Really appreciate this help. 

Jaime

fzidat

You are welcome Jaime!

 

Regards 

Jaime Maraví

Hi again Farid.. I managed to run the analysis you suggested. Do you think it is now ok? Is my stall torque then equal to the maximum torque here? See pìctures attached. 

Thanks very much for your help. 

Really appreciate it. 

Jaime

Jaime Maraví

Jaime Maraví said:

Hi again Farid.. I managed to run the analysis you suggested. Do you think it is now ok? Is my stall torque then equal to the maximum torque here? See pìctures attached. 

Thanks very much for your help. 

Really appreciate it. 

Jaime

See the pictures attached. They didn´t upload properly. Apologies

fzidat

Hello Jaime;

 

Yes, this maximum torque is where you have the unstable balance. 

 

In addition to that, if you varry the current supply you can plot a 3D curve, and then you can extract Torque max vs current which allow you to extract Kt constant.

 

Regards  

Jaime Maraví

Very helpful idea..Thanks very much Farid. 

Another quick question if you don´t mind. Why is it we need to inject (Ia=I, Ib=-I/2, Ic=-I/2) so to get static torque? I guess with those currents, the rotor aligns to phase A and doesn´t move.. but, will you get the same using (Ia=I, Ib=-I, Ic=-I)? 

Thanks very much for your help. Really appreciate it. 

Jaime

fzidat

Hello Jaime;

 

I used Ia=I, Ib=-0.5*I, Ic= -0.5*I, this assuming that the current are sinus, so for time = 0, you have this set of currents.

 

But may be if you have square wave current, it is not the case, but the method still the same, you have to use in magneto static a set of current for time = 0 and turn the rotor to get the static torque.

 

Best regards 

Jaime Maraví

Farid zidat_20516 said:

Hello Jaime;

 

I used Ia=I, Ib=-0.5*I, Ic= -0.5*I, this assuming that the current are sinus, so for time = 0, you have this set of currents.

 

But may be if you have square wave current, it is not the case, but the method still the same, you have to use in magneto static a set of current for time = 0 and turn the rotor to get the static torque.

 

Best regards 

Thanks very much Farid for your help. 

Appreciate it. 

Jaime