## Electronics

#### Transition zone in magnets – Maxwell 3D

• fkrall
Subscriber

Dear all,

I am trying to simulate a four pole outer rotor BLDC- machine with a radial magnetized magnet ring whit a transition zone betwen the single poles in Maxwell 3D. Thus, the magnetic field is not jumping when changing from a south to a north pole (or vice versa). Everything works fine for magnets without a transition zone, here I only have to change the sign of the unit vector in the material properties. For easier understanding I drawed a small sketch, in blue without the transition zones and in red with the transition zones.

How can I set up the described transition zones? One way I think of, is seperating the single magnets in three parts (like in the picture bellow) and define the transition zones individually, but how?

Thanks!

• fkrall
Subscriber

Hi again!

I found the answer to my problem. I post it here, maybe it helps someone else.

Define the magnet as solid ring, so, without any seperations. Goto Project->Datasets and define the magnetization pattern. The values for phi on the x- axis and the amplitude (1 and -1) on the y- axis. The name of the dataset needs to start with a \$, so the name would be something like \$Mag_trapz. Clone an arbitrarly magnet in the material editor, set the values for Br and Hc as needed. Change the coordinate system type to cylindrical. Write -Hc*pwl_periodic(\$Mag_trapz,2*Phi/pi*180) in the magnitude field of the magnetic coercivity, of course Hc has to be replaced by it's value. I defined the x- axis of \$Mag_trapz in electrical degree, Phi is in rad, so, it has to be converted. Phi is the mechanical angle, so with the factor of two (the number of pole pairs) it is converted to electrical degree.

All the best