SPM and IPM simulations

Jawhar Ben Fredj_20487

Hi ,

I'm a new member in the altair community and i have some questions concerning IPM and SPM simulations .

1- In the 2D tutorial IPM brushless MOTOR , (Case 3: constant speed computation) why GAMMA is 45 and not 30 ? 

BACK EMF :

 

2- In the case constant speed computation , what is the difference between these two types of circuits? ( the interests )  

3- how to estimate the values of the phase inductnace of a motor for the case back electromotive force computation  ? 

Farid zidat_20516

Hello Jawhar;

 

Please find bellow the answers to your questions:

1- In the 2D tutorial IPM brushless MOTOR , (Case 3: constant speed computation) why GAMMA is 45 and not 30 ? 

==> This is just an example, but you are right, Gamma should be a value to maximize the torque and minimize the current, so, on has to make a first computation, varying gamma and current and plot the torque, for each current, we should plot the torque versus gamma and chose the right one. 

 

2- In the case constant speed computation , what is the difference between these two types of circuits? ( the interests )  

==> The main difference is that for the first one we knew the working point current + speed and the second one we don't.  The other difference, is that for the IPM machine we have a current close to sine shape (thanks to PWM) and the second one, the current is 6 step control, so the current is not really close to the sine shape.

 

3- how to estimate the values of the phase inductnace of a motor for the case back electromotive force computation  ?

 

There is a dedicated macro to estimate the inductance matrix, or please follow the IPM tutorial, at the end of this one you can find how to extract winding inductances. Please note that in both cases, the end winding inductances is not computed, but, they are computed in advance by the user with analytical formulas.

Farid zidat_20516

Hello Jawhar;

 

Please find bellow the answers to your questions:

1- In the 2D tutorial IPM brushless MOTOR , (Case 3: constant speed computation) why GAMMA is 45 and not 30 ? 

==> This is just an example, but you are right, Gamma should be a value to maximize the torque and minimize the current, so, on has to make a first computation, varying gamma and current and plot the torque, for each current, we should plot the torque versus gamma and chose the right one. 

 

2- In the case constant speed computation , what is the difference between these two types of circuits? ( the interests )  

==> The main difference is that for the first one we knew the working point current + speed and the second one we don't.  The other difference, is that for the IPM machine we have a current close to sine shape (thanks to PWM) and the second one, the current is 6 step control, so the current is not really close to the sine shape.

 

3- how to estimate the values of the phase inductnace of a motor for the case back electromotive force computation  ?

 

There is a dedicated macro to estimate the inductance matrix, or please follow the IPM tutorial, at the end of this one you can find how to extract winding inductances. Please note that in both cases, the end winding inductances is not computed, but, they are computed in advance by the user with analytical formulas.

Jawhar Ben Fredj_20487

Thanks Farid for your detailed answers , i will come to you if necessary . 

Farid zidat_20516

You are welcome !