Design of a distributed non-linear stabiliser in MG using synergetic control theory

作者:Hao, Ran; Ai, Qian*; Zhu, Yuchao; Jiang, Ziqing; Yu, Zhiwen
来源:IET Generation Transmission & Distribution, 2019, 13(11): 2134-2144.
DOI:10.1049/iet-gtd.2018.5429

摘要

Stability of inverter-dominated microgrids (MGs) faces many challenges such as inertia shortage, mutual interactions among converters and sudden external disturbances. To enhance the stability of MGs, a distributed non-linear stabiliser is designed in this study based on synergetic control theory. First, inverter interfaces are uniformly modelled as virtual synchronous generators, whose small-signal stability is then analysed with the state-space average method. Also, the objective of the following control strategy, i.e. the system unstable domain, is obtained. Second, macro-variables applicable to droop control are constructed based on the typical dynamic model and then the analytic expression of the controller output could be derived. When external disturbances occur, or droop coefficients with high gains are chosen, power system stability could be guaranteed by adding a non-linear stabiliser. Finally, taking a 9-node MG as an example, simulation verifies the feasibility of the proposed strategy in cases of small disturbances, large disturbances and mode transition.

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