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Net-zero emissions from electricity production and their effect on global warming have led to an increased focus on power production from different renewable energy resources. Wind energy, solar energy, and hydroelectric power currently lead this effort. However, newer technologies, such as wave energy for electricity generation, have significant potential. This thesis investigates the usability and integration of wave energy systems into the electricity grid. This form of energy also has substantial potential in applications such as remote island electrification, which historically has higher carbon emissions due to its reliance on fossil fuels for energy.

This thesis focuses on Uppsala University’s developed point-absorber-based wave energy converter connected to the grid via power electronics converters. This thesis investigates various grid-side power electronics controls to safely connect the fluctuating frequency and voltage from the wave energy converter to the fixed 50 Hz grid. Additionally, a hybrid energy storage system consisting of a battery and a supercapacitor reduces the effect of variability and increases the reliability. The results illustrate the increased controllability of power flow to the grid and improved power quality. Additionally, the use of supercapacitors also increased the battery's performance.

The other part of the thesis explores the use of wave energy for remote island electrification. A novel multimode converter control (grid-feeding, grid-support, isolated grid-forming) approach is modelled in MATLAB/Simulink in a grid-connected system. These control modes are switched based on the requirement and scenario of the island load. The result shows the seamless transition between different modes, restoration of the island’s load voltage, and the constant power supply in the case of a blackout at acceptable power quality. An experimental study using a wave energy system for island electrification in an isolated grid-forming mode is also performed. The result illustrates the formation of the required load voltage at 50 Hz frequency, along with the functionality of black-start. A novel experimental approach of using a SiC-based converter in a wave energy system for improved power quality is also performed. The load voltage and current harmonics are reduced in all the experimented switching frequencies and comply with the grid code requirements.