Objectives  This paper aims to solve the frequency fluctuation in a ship's power system caused by power disturbances.

  Methods  To this end, a battery energy storage method is introduced to balance the output power and demand power, and the variable universe fuzzy method is utilized for the secondary frequency control of the ship's power system. In order to improve the control precision, area control error and change rate of the controller input, an incremental method is used to design a scaling factor that will expand or reduce the universe in case the control rule is unchanged.

  Results  The simulation results show that a ship's power system which contains a battery can reduce the frequency fluctuation and make it stable in a short time.

  Conclusions  Compared with the traditional fuzzy control, the proposed method offers better performance under external disturbances and parameter perturbation. The proposal in this paper can guarantee robust stability and robust performance.