Harmonic analysis and comparison of the back EMFs of four permanent magnet machine with different winding arrangements

This paper investigates the back EMFs of four surface-mounted permanent magnet machines with different winding arrangements for education purpose. They are a): a 4-pole machine with integral-slot distributed winding, b): an 8-pole machine with fractional-slot distributed winding, c): a 12-pole machine with integral-slot concentrated winding and d): a 24-pole machine with fractional-slot concentrated winding. The harmonic analysis of the back EMFs with different windings is investigated by finite element analysis (FEA) in the software of Comsol. Furthermore, the harmonic comparisons among machines are preformed. Finally, the prototype machines of a, b and d are made in the laboratory for students to study different winding arrangements. Some measurements are also carried out to verify the FEA results.