Altium or Orcad are good options, but if your interest is study signal processing or control system applied to the power electronics, you can try with the toolbox of power electronics in Simulink.
The best software for scientific research are Matlab and LabVIEW if you need computing power or system modelling choose Matlab if you need a fast development or the best hardware interaction take LabVIEW
PSIM and PLECS are both good options in terms of interface. In the case of PLECS (Blockset option), you can use this along with Matlab and SIMULINK, giving more flexibility to your simulations.