Analysis, Modeling, and Design Considerations for the Excitation Systems of Synchronous Generators

Stefano Nuzzo, Michael Galea, Chris Gerada, Neil Brown

Research output: Journal PublicationArticlepeer-review

48 Citations (Scopus)


The traditional generating set is usually comprised of a classical, wound-field, salient-pole, or cylindrical rotor synchronous generator, excited by a separate smaller machine, via a rotating, uncontrolled diode rectifier. The effects of the commutation processes of the diode bridge are often overlooked and neglected. However, due to the uncontrolled nature of this process, the rectified voltage available at the main generator's rotor terminals can be significantly lower than the expected value. This is especially true for low-to-medium power rated systems. In this paper, a detailed investigation of these aspects is done and an accurate voltage drop prediction model is then proposed. The model is validated with finite-element analysis and with experimental results for a particular low-medium rated generating system in the 400 kVA power range. The validated tool is then integrated into an innovative design tool, which first performs an analytical presizing procedure and then utilizes a genetic algorithm approach to identify an optimal excitation system design, aimed at minimizing the voltage drop ensuing from the diode commutations, with minimum impact on the overall efficiency.

Original languageEnglish
Article number8049315
Pages (from-to)2996-3007
Number of pages12
JournalIEEE Transactions on Industrial Electronics
Issue number4
Publication statusPublished - Apr 2018


  • Diode commutations
  • excitation systems
  • rotating rectifier
  • synchronous generators (SGs)

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Electrical and Electronic Engineering


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