Analytical Estimation of Induced Voltage in Rotating Electrical Machines

Abstract

Whether for the estimation of circulating current in the parallel circuits of the stator winding, damper current in the rotor of a synchronous machine, or voltage oscillation in the stator winding, an exact calculation of induced voltage is always inevitable. However, even when using FEM software, this voltage estimation is a post-process calculation based on pre-calculated flux densities or vector potentials. Since the air gap flux density is the primer parameter used in analytical estimations, it is therefore desirable to have a general and programmable method for calculating induced voltages regardless of their origin based on the air gap flux density. The rotating Tensor and its projection function offer a suitable alternative for these kinds of estimations. In this paper, the projection function is used to present a general method of estimating induced voltage in rotating machines with different winding topologies. This has been done for integer and fractional multi-layer windings in different machines, as well as the damper bars in the rotor. The results are compared to FEM calculation.

Keywords

• Rotating electrical machines
• vector theory
• induced voltage
• winding factor
• integer and fractional winding