Performance analysis of a brushless and exciterless AC generator

In this paper, the authors propose a novel form of brushless AC generator that does not require a shaft-mounted exciter. The constructional details and operating principle of the generator are described and a method for computing the steady-state performance, using a combined circuit and field approach, is introduced. The two-dimensional finite element method (FEM) is used for calculating the magnetic field distribution at different times-steps, from which the EMF and current waveforms can be accurately determined. A technique for optimizing the use of computer internal memory, with a view of improving the accuracy of solution, is briefly discussed. Computed and experimental performance of a 1 kVA prototype generator are presented.