Analysis and Control of Energy Storage Systems in Microgrid

In micro grid, the voltage and frequency will fluctuate with the switching of large-power electric load. With inverter control of energy storage systems,both active and reactive power pumped into the utility grid can be controlled which could achieve the stabilizing effect of voltage and frequency. This paper addresses active and reactive power control strategies used in energy storage system to eliminate the fluctuation. The active power is controlled based on a frequency-droop characteristic and a complimentary frequency restoration strategy. The reactive power is controlled based on a voltage-droop characteristic and a load reactive power compensation strategy. The experimental results demonstrate the effectiveness of the proposed control strategy under various micro grid operating conditions.