Rescarch Of Hybrid Energy Storage Control Strategy For Renewable Energy Power Generation And Grid Connected Technology

With the increasing of wind power capacity and penetration, the adverse impacts to the grid have become more and more prominent. The contradiction between the demand of wind farm connected into the grid and the receptivity of the grid is getting expanded. Energy storage systems have been widely used to reduce the wind power fluctuations and improve receptivity of the grid. In response to this situation, this paper proposes the control strategy of hybrid energy storage system to stabilize wind power fluctuations, and analyses the capacity configuration method. Main contents are as follows.Firstly, this paper proposes a power allocation method of hybrid energy storage system for stabilizing wind power fluctuation. Based on the system model, energy storage devices undertake different stabilizing tasks depending on the particular characteristics. In this paper, the wind power is divided and distributed to batteries and supercapacitors from the frequency domain using empirical mode decomposition theory. Simultaneously, according to the state of charge, adjust power outputs of the energy storage to avoid over-charge or over storage discharge. Simulation result shows that the stabilizing effect is remarkable, and gives full play to the characteristics of the energy storage devices, maintaining the stability of state of charge.Secondly, since the stabilizing effect and economy impacted directly by the capacity configuration, a hybrid energy storage configuration method is proposed based on life cycle cost. The paper calculates the depth of battery using the rain-flow-counting method, and quantifies the life according to the equivalent cycle life curve. By analyzing the cost structure of each stage, the paper establishes capacity allocation model using the minimum annual cost as objective and state of charge, confidence as constraints. Simulation result shows that compared to traditional capacity configuration method, this method reduces the life cycle costs of energy storage system and more practical significance.Finally, combining the foregoing findings, the paper develops a hybrid energy storage application platform using Matlab GUI graphical interface, and compiles it as an independent executable file. The software has a good versatility and interactivity, and can be used for various wind farm power stabilizing and capacity configuration analysis.