System Efficiency Improvement Using Winding Changeover of BLWFSG for Oscillating Water Column Wave Power Generation

Abstract

Around the world, renewable energy is being researched to reduce fossil fuels. Renewable energy is classified into solar, wind, and bio energy. Among the various types of renewable energy, wave power is attracting attention because of its high energy density and eco-friendly facilities. In addition, research is needed to maximize energy production by improving wave power system efficiency since energy consumption is increasing every year. In this paper, a study was conducted to improve the system efficiency and energy production of wave power generation by applying the winding changeover for the brushless wound field synchronous generator (BLWFSG). First, the generator structure is analyzed and generator modeling is performed to predict the accurate performance and system efficiency for BLWFSG. Then, it is divided into exciter, rectifier, and generator. The rectifier is used to generate field current in between the exciter and generator. Therefore, the nonlinearity parameters of exciter and generator are calculated for accurate performance prediction of BLWFSG. In addition, it was used to calculate generator performance through modeling with rectifier and exciter including nonlinear parameters. Finally, the system efficiency is calculated by considering both the power converter and generator losses. Second, the effect of the winding changeover was confirmed to improve the system efficiency of BLWFSG. There are series-single change, pole change, star-delta change, and series-parallel change as types of winding changeover. Therefore, the type and performance of the winding changeover are reviewed considering the system loss and diving points. Finally, the system efficiency and energy improvement are confirmed through simulation by applying the selected winding changeover technology.