Influencing Power System Dynamics with Active Filters
(2025)Department of Automatic Control
- Abstract
- The transition to renewable energy and distributed energy sources is transforming power systems, increasing the need for active filtering systems to maintain power quality. This thesis presents a comprehensive study of control strategies for Active Dynamic Filters (ADF), focusing on how the control strategies: PI control, cascade control, direct feedforward, and passive damping can be used to directly control the output current Iout and influence system dynamics such as stability, bandwidth and achievable pole placement.
A modular modelling framework was developed using state-space representations and the linear fractional transform, enabling flexible and systematic analysis of the different control strategies. Using this framework the... (More) - The transition to renewable energy and distributed energy sources is transforming power systems, increasing the need for active filtering systems to maintain power quality. This thesis presents a comprehensive study of control strategies for Active Dynamic Filters (ADF), focusing on how the control strategies: PI control, cascade control, direct feedforward, and passive damping can be used to directly control the output current Iout and influence system dynamics such as stability, bandwidth and achievable pole placement.
A modular modelling framework was developed using state-space representations and the linear fractional transform, enabling flexible and systematic analysis of the different control strategies. Using this framework the different control strategies were evaluated by studying Bode and pole-zero plots, and by using root locus techniques. To assess what behaviour is possible when using the different control strategies the regions of possible stable closed-loop pole placement were also studied.
A method for selecting control parameters that maximize the bandwidth when subject to stability constraint was presented. Furthermore, a tuning approach that ensures stability for uncertain grid conditions was also presented.
Results demonstrate that the combined use of PI control, cascade control, direct feedforward, and passive damping provides the most effective and robust solution, enabling direct control of the output current Iout. The proposed workflow lays a solid foundation for future implementation in more complex, realistic systems. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9207792
- author
- Krés, Gustav
- supervisor
- organization
- year
- 2025
- type
- H3 - Professional qualifications (4 Years - )
- subject
- report number
- TFRT-6279
- other publication id
- 0280-5316
- language
- English
- id
- 9207792
- date added to LUP
- 2025-08-08 15:10:22
- date last changed
- 2025-08-08 15:10:22
@misc{9207792,
abstract = {{The transition to renewable energy and distributed energy sources is transforming power systems, increasing the need for active filtering systems to maintain power quality. This thesis presents a comprehensive study of control strategies for Active Dynamic Filters (ADF), focusing on how the control strategies: PI control, cascade control, direct feedforward, and passive damping can be used to directly control the output current Iout and influence system dynamics such as stability, bandwidth and achievable pole placement.
A modular modelling framework was developed using state-space representations and the linear fractional transform, enabling flexible and systematic analysis of the different control strategies. Using this framework the different control strategies were evaluated by studying Bode and pole-zero plots, and by using root locus techniques. To assess what behaviour is possible when using the different control strategies the regions of possible stable closed-loop pole placement were also studied.
A method for selecting control parameters that maximize the bandwidth when subject to stability constraint was presented. Furthermore, a tuning approach that ensures stability for uncertain grid conditions was also presented.
Results demonstrate that the combined use of PI control, cascade control, direct feedforward, and passive damping provides the most effective and robust solution, enabling direct control of the output current Iout. The proposed workflow lays a solid foundation for future implementation in more complex, realistic systems.}},
author = {{Krés, Gustav}},
language = {{eng}},
note = {{Student Paper}},
title = {{Influencing Power System Dynamics with Active Filters}},
year = {{2025}},
}