Segmented Hybrid-PM Machines for Electric Vehicles; Semi-Analytical, Numerical and Experimental Study

In new generations of wind turbines and electric vehicles, cost reduction, efficiency improvement, enhanced reliability, extended maintenance life, noise and vibration reduction, as well as environmental considerations, are of great importance. In the meantime, segmented hybrid-permanent magnet (SHPM) machines, mainly the technology that combines segmented-PMs with different materials, dimensions and magnetization orientation, provide an opportunity to satisfy these demands. In this research, while presenting nine topologies of SHPM generator with segmented-PM rotor based on the Taguchi design of experiments method, a simple precise semi-analytical model is offered based on the subdomain method to estimate the magnetic performance characteristics of the SHPM machine. Magnetic partial differential equations (MPDEs) have been expressed in a pseudo-Cartesian coordinate system, and by using the suitable boundary conditions (BCs) and interface conditions (ICs), the general solution and their Fourier coefficients have been extracted using the separation of the variables approach. The performance characteristics of nine investigated SHPM machines were compared semi-analytically and numerically. A prototype SHPM machine has been fabricated and the results of semi-analytical modeling have been compared with the results of finite element analysis (FEA) method and the experimental tests in generating (charging mode). The FEA simulation and experimental test results have a maximum error percentage of about 3, confirming the high accuracy of the provided semi-analytical model. A comparison of induced voltage, torque ripple and magnetic torque is done between the studied topologies.