Learning Forum

[Binaya Adhikari]

Hi I need some help regarding stator tooth force calculation in PMSM. How can I find radial and tangential forces in transients (over time)?

[DELI]

Hi, you would need draw a polyline in front of the stator tooth and outside of band object, and there are two methods to do that:

1. Field report. If you are using version 2022R2 or newer, you can enable harmonic force calculation and create harmonic force report which has the radial and tangential force plot vs frequency over time.

2. Field calculator. You can create named expressions using field calculator to right the equation. Here is an example to calculate radial&tangential force in 2D Maxwell: 

1) Create Bradial and B tangential first: Bradial:ScalarX(ToCylindrical(,offset<0mm, 0mm, 0mm>))

                                                               Btangential: ScalarY(ToCylindrical(,offset<0mm, 0mm, 0mm>))

2) Create radial and tangential force from 1): Fradial: /(-(*(Bradial, Bradial), *(Btangential, Bttangential)), *(mu0, 2))

                                                                        Ftangential: /(*(Bradial, Btangential), mu0)

 

[Binaya Adhikari]

 

Thank you.

But I want to find out how these radial and tangential force acting on the tooth vary overtime.

So, when I want to create a field plot with time on x-axis and these forces on Y axis, I just get a vertical line at the end of simulation time as seen in the plot.(My simulation stop time is 15 ms).

How can i visualize these forces over time?

 

[DELI]

There is one more step in field calculator, integrate the Ft on the polyline. And you would be able to create transient report with Ft vs Time, instead of using field report.

[Binaya Adhikari]

Thank you, your suggestions have been really helpful but when integrate Ft and Fr on polyline and create  new variables(say Ft_final and Fr_final), I can't find those variables in transient report. How can I export those variables from fields report to transient report.

Also, I couldn't find the newly created variables(Ft_final and Fr_final) on fields report itself when i tried to plot it.

Could you help me through the process like you have done in your very first reply?

 

[DELI]

Hi, you would need add an expression cache in solver setup (expression cache tab), re-run the simulation, it should show up in transient report.

[Binaya Adhikari]

Thank you.

I got few more questions,

 

1. While ploting graphs from fields report I get it over time but I want it over angular position. How can i get it over angular position?(Like in the figure below)
2. I want to provide PWM excitation to 3 phase motor which is modelled in ANSYS. is there a way to provide this excitation directly from MATLAB? How can i approach this problem?

[DELI]

hi,

We might need more information, where do you want to plot the B field on, a point or a line?

 

Maxwell can link to Matlab, please refer manual for more details.

[Binaya Adhikari]

I want to find the waveform pf B field on a point and over a polyline both. To be more specific, i want to find a point and a polyline that I drawn on a stator teeth