Wind turbines fitted with hydrostatic transmission: performance and turbulence effects

In this work, we examine the potential advantages of using hydrostatic transmission over the traditional gearbox systems on horizontal-axis wind turbines. For this purpose, a series of controlled input experiments were performed at various inflow conditions. The power curve of the wind turbine as function of the tip-speed ratio shows an increase in the hydrostatic transmission and the operational cut-in speed. Significant benefits of the hydraulic wind turbine include the reduced weight and the placement of key components at ground level, which leads to greater floating stability over the traditional drive train in the hub. This is particularly useful for offshore applications, where substantial reduction of the cost of energy cost production is clearly possible; on the order of 20%. Furthermore, the displacement of the center of gravity near to the base of the turbine allows for greater stability in floating platforms. Based on the power spectrum model of Tobin et al (2015), we explore the power spectral response of the hydraulic wind turbine and assess the impact of turbulence on the power production with HST and regular drivetrain.