Adaptive Droop Control of AC/DC Hybrid Micro-grid Interlinking Converter

In order to improve the AC/DC sub-grid voltage accuracy of the traditional normalized droop control, an adaptive droop control strategy for AC/DC hybrid micro-grid interlinking interface is proposed. The proposed control strategy can not only reduce unnecessary power exchange while ensuring the bidirectional flow of power between AC and DC sub-grids, but also improve power transmission accuracy to realize a better compensation of the voltage deviation. As for the island mode of low-voltage hybrid AC/DC microgrid, the relationship between droop coefficient and transmitted power is deduced first. Then, the voltage variation is introduced to construct the operating criterion that characterizes the system load condition. Based on the above analysis, a control strategy whose droop coefficient is changing adaptively is designed. Moreover, considering the variation of line impendence, a control strategy is proposed to realize power distribution properly and suppress circulating current between parallel ICs. Finally, a simulation model of hybrid AC/DC microgrid is built on the Matlab/Simulink, and the effectiveness and superiority of the proposed control strategy are verified by simulation results.