Discrete simulation of 3-phase inductive load
These are your general four equations:

\$V_1 - V_n = R_1 \cdot i_1 + L_1 \cdot \frac{di_1}{dt}\$ 

\$V_2 - V_n = R_2 \cdot i_2 + L_2 \cdot \frac{di_2}{dt}\$

\$V_3 - V_n = R_3 \cdot i_3 + L_3 \cdot \frac{di_3}{dt}\$

\$i_1 + i_2 + i_3 = 0\$

Now e.g. with 

\$i_3 = -i_1 - i_2\$ 

you can take the third equation, replace \$i_3\$, and express \$V_n\$ as

\$V_n = V_3 + R_3 \cdot i_1 + L_3 \cdot \frac{di_1}{dt} + R_3 \cdot i_2 + L_3 \cdot \frac{di_2}{dt}\$

Replacing \$V_n\$ in our first two equations gives you two equations with the unknowns \$i_1\$ and \$i_2\$ which you can discretisize now. 

If you want to go into more complex systems I fully agree with Elliot Alderson that a circuit simulator would be helpful. If you want to develop your own one, I strongy recommend to use the Nodal analysis methode.