An improved model of synchronous generator based on Finite Element Method analysis

A system of voltage equations for general synchronous machine, which results in an improved equivalent circuit of such a machine, is presented. Mutual couplings and dependencies of inductances with respect to rotor position are included in the circuit. A method for calculation of reactances of the equivalent circuit, which takes into account the actual form of air gap and MMF, saturation of iron, and their mutual connections, is described. The applicability of the proposed model for computation of static and dynamic states of synchronous machine is proven on an example of a generator. It is shown that the improved model can be reduced to the standard form by neglecting higher harmonics. The model enables calculation of electrical and mechanical parameters that affect the waveform of output voltage, noise and vibrations, which is especially important in operation of a frequency converter.