A Rapid Estimation of the Rotor Losses in High Speed Synchronous PM Machines

The rotor losses evaluation is a fundamental task in the electromagnetic design of synchronous machines, especially when the reached speeds are so high to exacerbate eddy-current phenomenon. Commonly Time-Stepping Finite-Element Analyses are applied for predicting synchronous permanent magnets machine performance, in terms of iron losses due to eddy-currents. This procedure offers benefits and drawbacks regarding precision and computing time. Moreover in a Time-Stepping simulation there is the need to reach a steady state condition to obtain meaningful results. In this paper the iron losses occurring in iron rotor and permanent magnets are calculated by means of both Time-Harmonic and Time-Stepping Finite Element Analysis. Such analyses are carried out on various models. It is shown that the results obtained by a Time-Harmonic analysis are comparable to those extracted by a Time-Stepping one, with particular care of the model. Furthermore, the proposed alternative takes shorter simulation times.