Hello,
I am trying to model a current in function of time across a 3D single-turn coil inside an electrical circuit. I used the Magnetic Fields and the Electrical Circuit physics and a time dependent study. In the electrical circuit there is a current source generating a pulse: i'd like to excitate the coil with a sawtooth, the ramp must be 500mA/µs, so I fill in as rise time=1µs, fall time= 0.0005µs, pulse width=1.0005µs, period=1.0005 µs
(i set the fall time to 0.005 instead of 0 to avoid the error:
'' Error in user defined function.
- Function: mod1.cir.pulse'')
I used the '' External U vs I'' node to match the electrical circuit with the coil and i set as current ''coil current (mf/stcdp1)''.
I defined a boundary feed in which the coil excitation is set to circuit(voltage) and a ground.
when I run the simulation an error occurs:
'' constraint found for variables in different segregated groups. try to merge these groups.
- feature: stationary solver1 (sol1/s1)
- error:constraint found for variables in different segregated groups. try to merge these groups.

Could you please tell me what's wrong with my simulation?
Thanks in advance for your help!