Modeling, Analysis and Control of Single and Multiple Micro-grid-Based Active Distribution Grids

• Author / Creator

  Kahrobaeian, Alireza

• Derived by economic, technical and environmental reasons, the energy sector is moving towards a new era of “Smart Active Distribution Systems” where clusters of converter-based distributed generation (DG) units, local loads and other filtering devices form micro-grids (MG), which can be regarded as the building blocks of future active distribution grids. However, several undesirable interaction dynamics could occur between the DG converters, which are usually equipped with high-order LC or LCL filters and system components such as power-factor correction capacitors, static and dynamic loads. Moreover, the lack of coordination between DG entities in single and multiple micro-grid systems results in inaccurate power sharing, frequency deviation and system instabilities. To solve these problems, this thesis provides detailed modeling, analysis and control of micro-grid systems with compromised voltage or power stability issues due to system uncertainties in presence of different types of loads, electronic devices or line parameter variation. Several robust converter-level control interfaces are proposed to mitigate such stability challenges in both voltage-controlled and current-controlled converters. Furthermore, accurate power sharing and coordinated control of multiple micro-grids is achieved by developing a new system-level hierarchical distributed networked-based control strategy which can provide active synchronization and power-tie regulation between multiple micro-grid entities in large active distribution systems. Simulation and experimental results validate the effectiveness of the proposed control schemes.

• Subjects / Keywords

  • Networked control
  • Micro-grid
  • Flexible DG Interface
  • Active synchronization
  • Active distribution system

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R36H4CZ7W

• 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.