As you know, high side IGBTs requires isolated power supplies. One transformer and 4 isolated outputs can work. But,be sure that the isolation capacitance between outputs and input-output is very low. Otherwise high dV/dt can be problematic.
If anybody knows the calculation of the maximum allowable isolation capacitance value, please give an explanation here.
Additionally, bootstrap power supply can also work. In this method only one power supply is needed. But IPM producers doesnt recommend it.
Regards,