Analysis and performance of a surface-mounted NdFeB permanent-magnet a.c. generator

This paper presents the design, analaysis and performance of a permanent-magnet a.c. generator with surface-mounted NdFeB permanent magnets. By incorporating a soft-iron pole piece on each rotor pole, the quadrature-axis synchronous reactance is increased, with a consequent improvement in the voltage regulation. The finite element method is used for computing the magnetic field distribution, from which the steady-state machine parameters can be determined. A prototype generator was built and tested for verifying the theoretical analysis.