Fabrication and Experimental Analysis of an Axially Laminated Flux-Switching Permanent-Magnet Machine

The traditional flux-switching permanent-magnet machines (FSPMMs) with radial lamination have serious partial magnetic saturation for their nonlinear magnetic path, where the maximal flux density is usually more than 2.0 T occurring at the edges/tips of stator teeth or rotor poles. In this case, the core loss of FSPMMs becomes evident especially beyond the rated speed, which leads to decrease of output power, torque/power density, and efficiency. To overcome these problems, an axially laminated flux-switching permanent-magnet machine (ALFSPMM) with high grain-oriented silicon steel stator and rotor cores is proposed. The detailed fabrication procedures are presented in this paper. The theoretical characteristics of the ALFSPMM, such as back electromotive force, self-/mutual inductance, and cogging torque are calculated by the two-dimensional finite-element method (FEM). The influence of misalignment between the stator core and the rotor shaft (a common issue in motor manufacturing) is investigated by the FEM. Experimental measurements of the prototype machine are presented to validate the FEM calculation. In addition, a simple low-cost method to measure the cogging torque is also presented in this paper.