Power management and control coordination strategy for autonomous hybrid microgrids

Abstract

This study presents an improved power management and control coordination strategy for autonomous hybrid microgrids (MGs). The new strategy aims to reduce the continuous operation of interlinking converters (ILCs) under all load conditions, and thereby avoids the significant power loss on the ILCs that adversely affects the operational feasibility of the hybrid MGs. The hybrid MG considered in this study consists of multiple alternating current and direct current sub-microgrids (SMGs) with different voltage levels. The hierarchal coordination of power management and control strategy for autonomous hybrid MG is introduced and analysed. The designed system includes both the primary and secondary control levels to ensure a seamless and accurate transfer of power among the SMGs. A new technique to ensure the continuous power flow among the SMGs while minimising the continuous operation of the ILCs in the islanded mode is presented with a focus on the secondary control level. Five scenarios of transferring power among SMGs are analysed using MATLAB/Simulink. The results indicate that the system's high level of flexibility in managing the power flow at different control levels can be achieved by the proposed approach.