高可靠性三相多功能并网变换器研究

The three-phase multi-functional grid-connected converter (TMGC) combines the power quality control function while realizing the connection with microgrid, which also has an important application prospect. In order to improve the operation reliability of TMGC, the reconstruction technology and fault tolerant control strategy of TMGC are proposed in this paper. Firstly, a fault diagnosis method for the open circuit fault of the converter is adopted. The fault diagnosis method is carried out according to the characteristics of midpoint voltage deviation before and after fault and the real-time switching state. Secondly, a TMGC reconstruction topology is proposed to realize the reconstruction of TMGC when secondary faults occur, which can enlarge the fault tolerance space. Then, the fault-tolerant control strategy of TMGC is proposed, which combines harmonic suppression control, PQ control and pulse reset method, so that TMGC can continue to realize power control and harmonic suppression functions of grid-connected microgrid after failure. Thus, a high reliability three-phase multi-functional grid-connected converter (HRTMGC) is formed. Finally, the Matlab/Simulink simulation results prove the effectiveness of the proposed reconstruction technology and its fault-tolerant control strategy. © 2022 Food and Fermentation Industries. All rights reserved.