Modeling, Analysis and Stabilization of Converter-Dominated Power Distribution Grids

• Author / Creator

  Radwan, Amr A A

• The energy sector is moving towards extensive use of power electronic (PE) converters to interface distributed generation (DG) units and modern converter-interfaced loads (CILs). Therefore, the conventional distribution-grid is gradually transformed into a multi-stage PE converter-dominated network. However, interaction dynamics among equivalent source and load converters may adversely influence the overall stability even if each converter stage is inherently functional and stable.
  In multi-cascaded PE stages, the equivalent load/source admittance ratio should satisfy the Nyquist stability criterion to ensure stable operation. Moreover, tightly-regulated PE converters induce negative input admittance in the small-signal sense, which reduces overall stability margins.
  This thesis addresses interaction dynamics in emerging PE distribution systems by using small-signal linearization to derive equivalent input/output admittance models of typical PE converters. Active compensators are designed to maintain the system stability. Theoretical analysis and extensive simulation results are presented to validate the developed models and the proposed active compensators.

• Subjects / Keywords

  • Constant Power
  • Converters
  • Stabilization
  • Microgrids
  • Nyquist

• Graduation date

  Spring 2012

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R37603

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.