Integrated design and implementation of 120-kW horizontal-axis tidal current energy conversion system

A pragmatic and detailed sequence for the integrated design and implementation of a 120-kW horizontal-axis tidal current energy conversion system is presented, thus offering a valuable experience that contributes to the progress of tidal energy systems. The overall design of a full-scale system, containing the system design, control concept, and sea trial is provided in its entirety. The system design includes the turbine, pitch system, mechanical drive train, and electrical system. The blade parameters, hydrofoil data, and detailed structures of these electromechanical systems are shown. The control concept, comprising the grid-connected, maximum power point tracking (MPPT), and pitch controls, is proposed according to the analysis of the output power characteristic of the tidal energy system operation. The main objectives include confining the captured power at its rated value for protection when the rated current velocity is exceeded, capturing the maximum power below the rated current velocity, and regulating the active and reactive power to ensure electric power quality. A workshop test and a sea trial are carried out. The in situ experimental results of a complete operating period validated the effectiveness and feasibility of the entire system design, control concept, and experimental method.