An Improved Core-Loss Calculation Method With Variable Coefficients Based on Equivalent Frequency

Core-loss calculation is an important issue in design and analysis of electric machine, especially in high-speed applications. However, because of the diverse structure, flux distribution, and rotational variation of flux density, it is difficult to predict core loss in electric machines exactly. In this paper, a concept of equivalent frequency is proposed for arbitrary waveforms. An improved core-loss calculation method with variable coefficients based on equivalent frequency is established for electric machines. Finally, the improved core-loss calculation method is verified by experiments on doubly salient electromagnetic motor. The conclusions are also applicable to many other kinds of electric machines.