Performance Comparison Between Switching-Flux and IPM Machines With Rare-Earth and Ferrite PMs

Switching-flux permanent magnet (PM) machines compared with interior PM machines are presented to be interesting-solutions in terms of torque per volume density, compactness, active material layout, and cooling capability. The flux linkage is bidirectional, and the voltage is almost sinusoidal. These machines are then interesting for ac drives and field-weakening operation. Despite the lack of torque density, the adoption of low-cost magnets is investigated. Demagnetization in PMs is a critical issue and influences the choice of the machine.