Consensus-based P-f /Q-V droop control in autonomous micro-grids with wind generators and energy storage systems

This paper studies consensus-based P-f/Q-V droop control in autonomous micro-grids with wind generators and energy storage systems. The consensus control is achieved by deploying sparse and band-limited communication networks such that neighbouring DICs can communicate each other. Two droop control schemes, including (i) the uniform droop gain ratio scheme and (ii) the non-uniform droop gain ratio scheme, are examined. It will shown that the non-uniform droop gain ratio can indeed simplify the droop gain setting while maintaining more accurate power sharing. Modelling issues related to renewable generators and energy storage systems are also considered. Both DC-link voltage control for DICs with intermittent power input and superconducting magnetic energy storage (SMES) inductor current control for DICs are proposed. In order to capture dynamical behaviours of large deviations, non-linear Transient Energy Functions (TEFs) of the micro-grid are constructed to ensure the stability of the closed-loop system and accurate active/reactive power sharing even under large variations of loads/generations or even line outages. Real-time simulations of a 14-bus/6-converter micro-grid system with wind generations and energy storage systems are performed. Simulation results validate the effectiveness of this consensus-based droop control method.