Assessing short-term storage effects on hydrostatic wind turbine in presence of turbulent wind

One of the main challenges in wind turbine application is short-term storage of output power. Hydrostatic transmission  systems, in addition to their advantages such as increasing the reliability of the system and ability to use high-efficiency synchronous generators, give the system the chance to install the short-term storage to elevate quality and amount of the output power. The short-term storage in wind turbines is important because that significant amount of power in a wind profile lies in turbulence, which can be exploited by using suitable short-term storage such as an accumulator. In this paper, the effects of employing accumulator on the hydrostatic power transmission system are investigated. First, the nonlinear dynamic model of the wind turbine system is obtained. Then the nonlinear dynamic equations are linearized around steady-state trajectory of the system. Control system is designed based on proportional-integral-derivative control method with switching capability overall operation regions. During various simulation scenarios with hydrostatic transmission without the accumulator and with different accumulator size, it is proved that employing accumulator in the wind turbine improves the quality and quantity of the output power. The results reveal that with right choice of the accumulator, output power of the wind turbine increases significantly.