An Improved Superimposed Frequency Method for Power Sharing and Voltage Regulation in DC Microgrids

The superimposed frequency method is a desirable power-sharing decentralized method in DC microgrids. Accurate power sharing is achieved based on a superimposed small AC signal. However, limited load range, considerable bus voltage drop, and incomplete controller design principles limit its practical application. To solve these issues, in this paper, the causes of issues with the traditional superimposed frequency method are first investigated. Accordingly, an improved superimposed frequency method is proposed. Furthermore, simulated annealing-based controller design principles are proposed, considering both system stability and dynamic performance. Finally, the effectiveness and advantages of the proposed control method are verified based on the simulation and experiment results.