A Consequent-Pole Hybrid Exciter for Synchronous Generators

Stefano Nuzzo, Paolo Bolognesi, Giovanni Decuzzi, Paolo Giangrande, Michael Galea

Research output: Journal PublicationArticlepeer-review

20 Citations (Scopus)


In low-to-medium power generating sets, a self-powered brushless excitation system is typically employed. This solution is cost-effective, simple and compact, but it suffers from an unreliable voltage build-up at start-up, a slow dynamic response and a relatively low efficiency for the exciter. The push towards more effective, reliable and efficient products has recently led to consider excitation systems equipped with permanent magnet exciters and controlled rotating converters, but their diffusion is limited by their higher complexity and cost. This article investigates the utilization of a hybrid excitation for the exciter, aiming to join the benefits of field windings and permanent magnets. As a case study, this concept is applied to a commercial mid-size generating set adopting an industrial perspective, aiming to maximize the benefits while minimizing the required modifications in the system design. After a preliminary analysis, a consequent-pole layout with surface-mounted bonded magnets is then selected as the most effective solution. Theoretical considerations, numerical analysis and experimental validation are reported to show that the hybrid excitation concept can actually lead to a significant reduction of the exciter field losses as well as to other appreciable side benefits with a very limited impact on the present design of the generating set.

Original languageEnglish
Article number9151376
Pages (from-to)368-379
Number of pages12
JournalIEEE Transactions on Energy Conversion
Issue number1
Publication statusPublished - Mar 2021


  • Brushless excitation systems
  • consequent-pole
  • efficiency
  • generating set
  • hybrid exciter
  • reliability
  • synchronous generators
  • voltage build-up

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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