Computationally Efficient Semi-Analytical Model for the Calculation of the No-Load Magnetic Field in High-Speed Permanent Magnet Machines

High-speed slotted permanent magnet (PM) machines are characterized by high power density and high efficiency, which makes them widely used in different applications. Consequently, fast and accurate models which predict their behaviour are highly required. Eddy current effects, which, due to the existence of slots, are present even at no-load conditions, impose long solving time for finite element models (FEM). As an alternative, this paper presents a harmonic model (HM) for the calculation of no-load magnetic field in high-speed slotted permanent magnet machines. Beside having inherently shorter solving time than FEM, HM proposed in this paper brings additional reduction in the model size and solving time. This is achieved by identifying harmonic components which actually contribute to the electromagnetic field. Components which make no contribution, but are present in the generic field solution, are eliminated from the model.