Analysis of a Brushless Wound Rotor Synchronous Machine Employing a Stator Harmonic Winding

Abstract

This study proposes a new topology for brushless operation of a wound rotor synchronous machine (WRSM) employing a stator harmonic winding. It is based on generating an additional six-pole magneto-motive force component without the use of an inverter. In this topology, six thyristor switches are used to create harmonic currents for brushless operation of the machine. The usage of stator harmonic winding has the advantage of configuring the winding for six poles or any other combination based on the output requirement. In the proposed topology, a six-pole winding arrangement is used to generate a six-pole air-gap flux component aimed at rotor excitation for brushless operation. On the rotor side, two windings, namely rotor harmonic winding (to intercept the air-gap harmonic flux) and field winding, along with a diode rectifier are mounted. 2-D finite element analyses and experiments were carried out to analyze the brushless operation of the WRSM.