Open AccessLow‐voltage ride through control strategy of virtual synchronous generator based on the analysis of excitation state
Author(s) -
Shi Kai,
Ye Haihan,
Xu Peifeng,
Zhao Dean,
Jiao Long
Publication year - 2018
Publication title -
iet generation, transmission and distribution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 110
eISSN - 1751-8695
pISSN - 1751-8687
DOI - 10.1049/iet-gtd.2017.1988
Subject(s) - control theory (sociology) , voltage droop , low voltage ride through , permanent magnet synchronous generator , grid , ac power , transient (computer programming) , fault (geology) , correctness , computer science , generator (circuit theory) , voltage drop , power (physics) , overvoltage , voltage , engineering , control (management) , voltage source , electrical engineering , algorithm , mathematics , physics , geometry , quantum mechanics , artificial intelligence , seismology , geology , operating system
Virtual synchronous generator (VSG) possesses the advantage of friendly interaction with power grid by simulating synchronous generator characteristics. However, its low‐voltage ride through (LVRT) capability is insufficient. The excessive output current of VSG easily causes wind turbines to break away from the power grid, which will exacerbate the negative impact of grid fault. Thus, a new LVRT control strategy is proposed based on the analysis of excitation state for VSG. The droop characteristic, reactive power loop and active power loop of the VSG are improved, respectively, by specifically analysing the response characteristics of VSG. Moreover, the additional current loop is redesigned to assist the system operating in the under excitation state and suppress unbalanced currents without changing the original VSG characteristics. Furthermore, a new orientation method is adopted to accelerate the transient process and achieve better transient performance. It is worth noting that the proposed control strategy does not need switch control algorithm with smooth handoff algorithm under grid fault, and it can deal with both symmetric and asymmetric grid voltage drop problems at the same time. The correctness and feasibility of proposed scheme are verified by rigorous theoretical deduction and complete simulation verification.