Prediction of Open Circuit Characteristics of Brushless Alternators by Finite Element Method
Performance prediction in brushless alternators is conventionally carried out using traditional methods which combine analytical and empirical knowledge. These methods lack accuracy due to complex geometry and non-linear characteristics of magnetic materials associated with the machine. Hence, numerical ﬁeld computation methods like ﬁnite difference method (FDM), boundary element method (BEM) and finite element method (FEM) have been employed for prediction and analysis of machine characteristics by electro-magnetic ﬁeld analysis. Out of these techniques, FEM is increasingly used by designers due to its ability to handle complex geometry and presence of non-linear magnetic materials. This paper presents a method for prediction of open circuit characteristics (OCC) of brushless alternators based on FEM. A 2D FE model of a 45 kVA, 415 V, 3-phase, 4-pole salient pole brushless alternator is developed and the open circuit characteristic (OCC) is predicted and validated by experiment on the prototype machine.
Keywords - Brushless Alternator, Finite Element Method, OCC, Prototyping, Maxwell’s Equations.