This paper presents a parametrized optimization with constraints associated to a current searching method. The goal of the optimization is to minimize the torque ripples of an interior permanent magnet powertrain electric motor over the maximum torque-speed curve by injecting current harmonics into the power supply. The resulting current harmonics table can be used as a look-up table for the motor drive controller to reduce motor torque ripples at given torque-speed operating points. This paper also evaluates the impact of the current harmonic injection on the iron losses in the motor stator and rotor, and on the eddy current losses in the magnet.