Design and Analysis of Brushless Multiphase Synchronous Generator With Dual-Pole Six-Phase Symmetrical Winding

Abstract

Brushless wound-field synchronous machines (WFSMs) have long been employed in a wide range of applications due to their maintenance-free operation and high reliability. Brushless excitation is typically achieved through the deliberate injection of harmonic or subharmonic currents into the stator winding using specialized converters and complex winding arrangements. Alternative topologies, such as embedded exciter-based synchronous machines, have also been explored, utilizing magnetically decoupled dual windings for excitation. In recent years, multiphase machines have emerged as attractive alternatives to conventional three-phase systems, offering advantages such as lower converter switch ratings, improved fault tolerance, and enhanced reliability. By exploiting additional degrees of freedom, multiphase machines enable independent control of multiple spatial harmonic fields, facilitating rotor excitation and power transfer in WFSMs. Through appropriate stator current control, dual magnetic fields with different pole pairs can be generated and regulated independently, resulting in higher torque density and improved slot and core utilization compared with their three-phase counterparts. Motivated by these advantages, this article presents the analysis and design of a six-phase brushless multiphase synchronous generator. A 2/4-pole configuration is adopted to demonstrate the generation of dual magnetic fields from a single six-phase stator winding. The operating principles and key performance characteristics of the proposed machine are validated through finite-element analysis and experimentally verified using a laboratory-scale prototype.