This paper first develops a modified control loop to realize flux-weakening in PMSMs. For a given load torque, the modified control loop ensures the maximum speed of the PMSM is always reached at the optimized path. Next, a benchmark test system based on the co-simulation of Simulink, PSIM and MotorSolve is developed to obtain a representative simulation of the PMSM traction drive. With the simulated currents, the 3-D simulation tool based on finite element analysis, MagNet, is used to predict the motor loss. Using this benchmark system, the influence of SVPWM and DPWM0-3 on the traction drive and motor losses, over the entire operating range is investigated. Furthermore, over-modulation of SVPWM is implemented to investigate its effect on control performance and holistic loss reduction. The simulation results validate the effect of over-modulation to reduce the inverter loss and motor loss in the flux-weakening region.