Battery–supercapacitor hybrid energy storage system for wind power suppression based on the turbulence model of wind speed

Abstract

Based on the turbulence model, the volatility of real-time wind speed is discussed, which is composed of an average component and a fluctuant component. By deriving the probability density function of fluctuant wind speed and investigating the probability density curve, the authors decompose the fluctuant wind power into the steady fluctuation and peak fluctuation. According to the properties of steady fluctuation and peak fluctuation, the authors determine that the energy storage system applied into the real-time wind power fluctuation should be of the performance of high power density, high energy density and long cycle life. Through the comparative analysis on the energy storage performance, the battery and supercapacitor are proved to be suitable for regulating the steady and peak fluctuation, respectively. According to that task assignment, the energy storage performance of a battery–supercapacitor hybrid system is investigated. Based on the wind power decomposition, this study develops a new capacity configuration method for the hybrid system and gives an example analysis. By that method, the battery and supercapacitor in the hybrid system can be allocated proper energy and power capacity to balance the steady and peak fluctuation, respectively. Consequently, their energy storage merits can be fully utilised.