In this paper, two novel morphing parametric models for flat-to-V-type (FV) and for spoke-to-V-type (SV) Permanent Magnet (PM) synchronous machine configurations are introduced. A combined multi-objective design optimization method employing Design of Experiments (DOE) and Differential Evolution (DE) algorithms was developed and implemented. A Central Composite Design (CCD) approach combined with the Response Surface Method (RSM) was used to perform a sensitivity study from which the significant independent design variables were selected for the DE design optimization procedure. A computationally efficient-Finite Element Analysis (CE-FEA) technique was employed to evaluate the electromagnetic performance of the candidate designs. Three optimization objectives are concurrently considered for minimum material cost, power losses and torque ripple, respectively. The DE optimization results enable the systematic comparison of three interior permanent magnet (IPM) motor topologies: flat-type, generic V-shape and spoke, respectively. A discussion on the relative merits of each topology is included.