Iron Loss Estimation Under Pulse Width Modulation Excitation in Permanent Magnet Synchronous Motors

As environmental concerns grow globally, the necessity to reduce polluting emissions is of key importance to the survivability of the automotive industry. The continuously rising number of vehicles that employ hybrid or fully electric powertrains leads to the need for more efficient electric machines. The most commonly used type of electric motor in the vehicular application field is the permanent magnet synchronous motor, thanks to its high power-density and efficiency. When implemented in a vehicle, the electric machine is fed by a PWM supply, whose harmonic content increases the power loss of the motor. The scope of this research is to improve the accuracy of the iron loss prediction in permanent magnet synchronous motors fed by PWM supply, employed in traction applications. The ability to estimate the loss quickly and correctly is of fundamental importance in the early stages of machine design, allowing proper optimization. In this work, a new iron loss estimation method using finite element analysis software is introduced. First, an overview of iron loss in electrical machines is given, presenting its physical meaning and the modelling approaches present in the literature, based on the concept of loss separation. The implementation procedure of the estimation method is explained and its performance is analyzed and compared to the standard estimation procedure applied in the industry. Last, the estimation method is validated on a second motor application to better understand its behavior and overall performance.