I am trying to simulate the structure of a thermoelectric generator (TEG) in Comsol Multiphysics and analyse the potential generated at the terminal through the Seebeck effect. Still, I am getting errors during the study. Are there any resources that I can refer to for simulating TEG in COMSOL multiphysics?

I applied temperature boundary conditions for both the heat source and heat sink in heat transfer in the solids section and terminal boundary conditions for the terminal using a circuit option in the electric current section

What boundary conditions should we select for the simulation?

error:

Failed to find a solution.

Electric Currents

Singular matrix.

For mesh case 0 there are 14117 void equations (empty rows in matrix) for the variable comp1.V.

at coordinates: (0,0.001,0), (0.000103119,0.000907919,0), (0,0.000714286,0), (0,0.00095253,4.80187e-05), (9.27978e-05,0.001,9.6646e-05), ...

and similarly for the degrees of freedom (empty columns in matrix).

In Electric Currents:

Returned solution is not converged.

Not all parameter steps returned.