الفهرس 
Ocean Energy
Speed Estimation Techniques forOnly 14 pages are availabe for public view
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Abstract
Renewable energy sources like wind, solar and oceans renewables, gain an increasing attention due to the limited nature of fossil fuel supplies, national requirements for security of supply, as well as political pressure toward the reduction of carbon emissions and use renewable energy as it is clean and will never run out.
Recently, Wave Energy Conversion System (WECS) gains an increasing attention. There are many methods for capturing energy from wave and convert it to electrical energy. Mechanical interface such as Oscillating Water Column (OWC), water turbines, and hydraulic systems are used to convert the linear motion to rotational and hence conventional rotary electrical machines such as induction or synchronous generators can be used to generate electricity. However, the main drawbacks of these Wave Energy Conversion Systems (WECS) are their mechanical complexity and low energy-conversion efficiency. Alternatively, direct-drive WECS, which is based on linear generator connected directly to a buoy, eliminates the need for complex mechanical interface. As a result of reducing the moving parts, the overall system efficiency is increased and the maintenance rate is decreased. Many linear generators can be coupled with the direct-drive WECS such as induction generator with or without iron in the translator, switched reluctance generator, transverse flux machine, vernier hybrid machine, and Linear Permanent Magnet Synchronous Generator (LPMSG). One of the attractive direct-drive Wave Energy Conversion Systems (WECS) is the Archimedes Wave Swing (AWS) coupled to a Linear Permanent Magnet Synchronous Generator (LPMSG).
This thesis presents an integrated control approach for the back-to-back converter interfacing the LPMSG with the grid to extract the maximum power from the wave. The proposed Maximum Power Point Tracking (MPPT) technique is based on sensorless-speed control of the LPMSG to follow the wave. The Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) are adopted to estimate the speed of the translator. The optimal speed of the LPMSG is obtained from the instantaneous active power at the generator terminals.
Simulations for direct-drive WECS based on LPMSG are conducted using EMTDC/PSCAD software package to evaluate the dynamic performance of the proposed control strategy. Results show that EKF & UKF provide an accurate estimated speed with negligible error. Also results show that the proposed control for generator-side converter succeeds to extract the maximum power from wave and to follow the optimal speed. The proposed control for grid-side converter succeeds to deliver this power to the grid at constant voltage and frequency.
The dynamic Performance of the proposed system is tested under irregular wave. Moreover, a comparison between the performance of the proposed control strategy and the other control methods from literature under regular wave is conducted. The results show the superiority of the proposed system.