Date of Defense
27-5-2025 11:00 AM
Location
F1-2007
Document Type
Thesis Defense
Degree Name
Master of Electrical Engineering (MEE)
College
COE
Department
Electrical and Communication Engineering
First Advisor
Dr. Addy Wahyudie
Keywords
Disturbance observer, disturbance rejection, feedback linearization, grid side converter, machine side converter, permanent magnet linear generator.
Abstract
A typical Permanent Magnet Linear Generator (PMLG)-based ocean wave energy system consists of an electrical generator, a Machine-Side Converter (MSC), a Grid-Side Converter (GSC), a DC-link capacitor, and a passive filter—such as an L filter or LCL filter—to connect the GSC to the grid. The main objective of this work is to control the GSC using a disturbance observer-based control technique to inject constant power and balanced current into the grid under both balanced and unbalanced grid conditions.
This thesis presents a controller for the converter that integrates a state-feedback controller with a disturbance observer. The feedback controller stabilizes the nominal closed-loop system, while the disturbance observer functions as a servo-compensator to mitigate the impact of model uncertainties and unknown disturbances. Robustness—i.e., the ability to handle uncertainty and noise effectively—is one of the key performance criteria in evaluating the proposed control method.
Therefore, this work begins by deriving an averaged wave energy converter (WEC) model, which is then simulated in MATLAB/Simulink. Additionally, the controller model is developed and derived in the Stationary Reference αβ Frame.
Simulation tests are carried out to validate the effectiveness of the proposed control technique using MATLAB, considering realistic scenarios and appropriate control settings. The results indicate that the proposed control strategy achieves satisfactory steady-state and transient performance under balanced grid voltage conditions; however, certain limitations are observed in the presence of unbalanced grid voltage.
Included in
DISTURBANCE OBSERVER IN GRID-SIDE CONTROLLER FOR WAVE ENERGY CONVERTERS
F1-2007
A typical Permanent Magnet Linear Generator (PMLG)-based ocean wave energy system consists of an electrical generator, a Machine-Side Converter (MSC), a Grid-Side Converter (GSC), a DC-link capacitor, and a passive filter—such as an L filter or LCL filter—to connect the GSC to the grid. The main objective of this work is to control the GSC using a disturbance observer-based control technique to inject constant power and balanced current into the grid under both balanced and unbalanced grid conditions.
This thesis presents a controller for the converter that integrates a state-feedback controller with a disturbance observer. The feedback controller stabilizes the nominal closed-loop system, while the disturbance observer functions as a servo-compensator to mitigate the impact of model uncertainties and unknown disturbances. Robustness—i.e., the ability to handle uncertainty and noise effectively—is one of the key performance criteria in evaluating the proposed control method.
Therefore, this work begins by deriving an averaged wave energy converter (WEC) model, which is then simulated in MATLAB/Simulink. Additionally, the controller model is developed and derived in the Stationary Reference αβ Frame.
Simulation tests are carried out to validate the effectiveness of the proposed control technique using MATLAB, considering realistic scenarios and appropriate control settings. The results indicate that the proposed control strategy achieves satisfactory steady-state and transient performance under balanced grid voltage conditions; however, certain limitations are observed in the presence of unbalanced grid voltage.