Supervisor:
Professor Frede Blaabjerg

Co-Supervisor:
Assistant Professor Subham Sahoo

Assessment Committee:
Mohsen N. Soltani (Chair)
Professor Wilmar Martinez, Katholieke Universiteit Leuven Belgium

Electrical Engineering Professor Petr Korba, Zurich University of Applied Sciences (ZHAW), CH

Moderator:
 Associate Professor Mateja Novak

Abstract:

Nowadays, the development of renewable energy sources is steering us towards achieving net-zero carbon emissions. Microgrids have emerged as a promising solution to effectively integrate RES into power systems, with power converters playing vital roles in this process. Recently, model predictive control (MPC) has gained attention for its simplicity, explicit constraints handling, and rapid response, making it suitable for diverse control requirements. However, the increasing complexity of power converters in microgrids presents challenges to this algorithm.

This PhD project focuses on addressing stability, dynamic performance, and robustness in MPC-based power conversion systems. Initially, an analysis identifies the root causes of instability, leading to adjustments in control equations and the development of a guideline for designing weighting factors using the Jacobian matrix. This guideline effectively describes the influence of weighting factors on system stability, making it a valuable tool for industrial MPC applications.

For dynamic performance, a novel approach incorporates flexible output voltage overshoot design into MPC, ensuring compliance with system specifications. This involves establishing the MPC controller model based on optimal duty cycle expressions and adjusting the weighting factor ratio to guarantee a desired system cut-off frequency. Additionally, robustness-enhanced methods are explored, focusing on Generalized Predictive Control (GPC) and parameter estimation using the Kalman filter.

In summary, this project contributes to the development of customized MPC design guidelines for power converters in microgrids. It provides a comprehensive approach to constructing MPC systems that meet various requirements, with a special focus on stability, dynamic performance, and robustness, offering an effective method for designing advanced power converter systems.