Analytical time-harmonic approach to calculate rotor eddy-current losses due to stator harmonics

Abstract

This paper describes an analytical approach to determine the losses in the rotors of synchronous machines due to stator space and time harmonics. Based on the formulation of electro-magnetic waves in the cylindrical coordinate system, different geometrical layouts and winding arrangements have been investigated. The analytically calculated results of eddy-current losses in different parts of the rotor, such as damper wedges, massive iron parts, screens and permanent magnets, are compared with numerical calculations, showing good coincidence. Analytical approaches help to understand the physics and allow optimal solutions to be found in a fast but still accurate way.