Adaptive voltage droop scheme for voltage source converters in an islanded multibus microgrid

Abstract

In this study, a novel voltage droop scheme for the parallel operation of voltage source converters (VSCs) in an islanded multibus microgrid is proposed. In this scheme, the voltage droop coefficient is defined as a function of respective VSC active and reactive power outputs. Thus, each VSCs voltage reference is adaptively drooped as a non-linear function of its active and reactive power outputs. This approach leads to reduction in the reactive power sharing dependence on real power control and system parameters such as mismatched connecting and line impedances. A multiobjective index is introduced for evaluating the scheme performance. The index is used as an objective function in an optimisation problem that is employed to obtain optimal parameters of the scheme. The detailed analysis shows that this scheme has a superior behaviour compared to the conventional voltage droop method, in view of the reactive power sharing and loads voltage control under all loading conditions. Simulation and experimental results show the good performance of the method for three paralleled VSCs in a multibus microgrid system.

Multitier decentralized control scheme using energy storage unit and load management in inverter-based AC microgrids

“…In the first step of control, the DGU controller designed based on the droop method [16,31] shares power among the intermittent and nonintermittent DGUs for amending the stability margin of the system, regulating voltage, and maintaining f .…”

Decentralised control method for DC microgrids with improved current sharing accuracy

“…The main objective of a coordinated control system is to prevent over stressing of any energy source and properly distribute the total power load to each DG in proportion to their rated powers [7,8]. To realise this, the so called droop control which employs own electrical parameters as global indicators is widely applied in MG systems due to its decentralised characteristic [9][10][11][12]. For ac MGs, the classical global indicators, namely frequency and voltage, are applied in P-f and Q-V droop controllers in order to provide power sharing.…”

Real‐time reactive power distribution in microgrids by dynamic programing

“…The objectives of the microgrid management system depend on the microgrid mode of operation: islanded or gridconnected. In islanded mode, possible objectives are to stabilize the system's frequency and voltage [8]- [9] or when working in autonomous mode, to minimize the consumption of fuel . In grid-connected mode, typical objectives are to minimize the fuel, total emissions, total power loss, or as considered in this work, to optimize the reactive power flow at the microgrid PCC [10]- [12].…”