Abstract: In order to maintain voltage and frequency stability of the microgrid under an islanding operation mode, energy storage systems are used within the microgrid to balance active and reactive power fluctuations.Based on a three-phase voltage power inverter, a d-q decoupling control strategy is adopted to control the charging and discharging powers of the energy storage system, and a simulation model of such a control strategy is established in Matlab/Simulink software. The example analysis shows that the active and reactive power output of the energy storage system under this control strategy features a fast response speed and high stability, and is available to maintain the voltage and frequency stability of the microgrid, which verifies the correctness and effectiveness of this control strategy.