No-load characteristics analysis and rated field current calculation of multi-phase synchronous generator based on nonlinear with FEM

Considering the magnetic nonlinear characteristic of iron core and its structural complexity, the calculation model of Multi-phase Synchronous Generator is established with nonlinear FEM. Then the method and analysis steps of no-load characteristics analysis and rated field current calculation are given in detail. On the basis of electromagnetic field calculation of the twelve-phase synchronous generator, the harmonic analysis of air-gap magnetic field is presented, as well as its no load characteristics. The calculated results of fundamental component are close to the measurement values, and it indicates that this method can be used in the calculation of electromagnetic field of the generator. Also, it gives the theoretical basis for the generator design. The rated field current is calculated based on iterative method, and the results of field current are consistent with the rated condition. This method has high practical usability, which may provide the reference for the calculation of rated field current of the common synchronous generator.