Intelligent compensation of irregular wave effects encountered on electrical power in wave energy systems

Compared to popular renewable energy resources such as wind and solar, the wave energy has the highest energy density and availability. However the utilization of wave energy systems are not as common as above-mentioned renewable energy sources due to irregular characteristics of the electrical energy produced by natural sea waves, besides high cost and complexity of the wave energy converters. Especially, irregular electrical power generated in direct-drive wave energy systems requires to be used with power electronic interfaces, energy storage units or hybrid energy systems before being connected to the load or utility. A hybrid power conditioner comprising of a power electronic interface circuit called as cascaded synchronous DC/DC buck-boost converter and a solar charged ultra-capacitor unit is introduced for direct-drive wave energy systems in this thesis. Fuzzy logic, fractional-order PID and classical PID controllers are designed to control power electronic circuits for performance improvements. In order to optimize the controller parameters, flower pollination algorithm and particle swarm optimization are employed. Effectiveness of the designed system in simulation and experiments with optimized controllers are tested considering both regular and irregular sea wave forms under different load contidions.