Computation of Iron- and Eddy-Current Losses in IPM Motors depending on the Field-Weakening Angle and Current Waveform

Due to the limited space availability and the high demand on power density and efficiency, the permanent magnet synchronous machine is suitable for application in parallel hybrid electric vehicles. The desired reduction of the vehicle's fuel consumption requires a good efficiency, and thus low losses. Therefore, the design process of the electrical machine has to include a loss calculation determining all losses such as iron losses, magnet eddy-current losses and Ohmic losses. Since the machine is operated over a wide range of operation points, the losses must be calculated depending on different values of the current, the field-weakening angle and the rotational speed. As the harmonic content of the magnetic flux has a significant effect upon the lamination's iron losses and the magnet's eddy-current losses, the effect of block-shaped currents and real current forms of PWM-fed machines are also studied in this paper.