Model Reference Adaptive Controller for Simultaneous Voltage and Frequency Restoration of Autonomous AC Microgrids

In an autonomous droop-based microgrid,the sys-tem voltage and frequency(VaF)are subject to deviations as load changes.Despite the existence of various control methods aimed at correcting system frequency deviations at the second-ary control level without any communication network,the chal-lenges associated with these methods and their abilities to simul-taneously restore microgrid VaF have not been fully investigat-ed.In this paper,a multi-input multi-output(MIMO)model ref-erence adaptive controller(MRAC)is proposed to achieve VaF restoration while accurate power sharing among distributed generators(DGs)is maintained.The proposed MRAC,without any communication network,is designed based on two meth-ods:droop-based and inertia-based methods.For the microgrid,the suggested design procedure is started by defining a model reference in which the control objectives,such as the desired settling time,the maximum tolerable overshoot,and steady-state error,are considered.Then,a feedback-feedforward con-troller is established,of which the gains are adaptively tuned by some rules derived from the Lyapunov stability theory.Through some simulations in MATLAB/SimPowerSystem Tool-box,the proposed MRAC demonstrates satisfactory perfor-mance.

直流微电网电压等级序列选择的影响因素研究

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海岛直流微电网电压等级序列选择的研究

直流微电网是未来智能电网的重要组成部分。目前,国内外关于海岛微电网电压等级选择的研究还处于初级阶段。本文在借鉴传统交流配电网电压等级序列选择的基础上,结合海岛负荷需求特点,分析了海岛负荷的供电需求、分布式电源的接入需求、配电方式、供电能力等影响因素,并在充分考虑上述影响因素下,给出了海岛直流微电网电压等级序列的三种范围。最后,以某星形拓扑结构海岛为例,确定其直流电压等级序列,并从经济性层面上分析了海岛电压等级序列与成本之间的关系,为未来海岛微电网的电压选择提供借鉴。