<p>The multi-microgrid has been attracted extensive attention for enhancing renewable energy utilization. The power fluctuation and load disturbance can lead to frequency deviation of multi-microgrid. Model-based control strategies cannot suppress frequency deviations effectively when disturbances occur on both the source and load sides because of the numerous system parameters in the multi microgrid. An optimal model-free control (MFC) strategy with distributed energy storage systems (DESS) is proposed to optimize frequency dynamic response and enhance stability of multi-microgrid in this paper. The proposed MFC strategy combines Riccati matrix and model-free theory to minimize frequency deviation. Additionally, a Smith predictor is added to compensate for time delays in communication channels. Moreover, a distributed energy storage systems (DAC) is adopted to adjust each energy storage unit’s output based on remaining capacity percentage to maximize DESS power output for frequency regulation. Finally, the proposed frequency control strategy and delay compensation scheme are verified effectively in achieving frequency stability through the simulation in isolated multi-microgrid system.</p>