A new precharging strategy for hybrid MMC based on HBSM and FBSM. Issue 1 (January 2020)

• Record Type: Journal Article
• Authors: Han, Lei; Jiang, Junfeng; Yao, Haitao
• Is Part Of: IOP conference series. Volume 740:Issue 1(2020)
• Publication Date: 2020-01
• Subjects: Materials science -- Periodicals; 620.1105
• DOI: 10.1088/1757-899X/740/1/012102
• Languages: English
• ISSNs: 1757-8981

Abstract

Abstract: Precharging of the modular multilevel converter (MMC) is an important basis for ensuring the normal operation of MMC-HVDC system. The hybrid MMC based on full bridge sub-module (FBSM) and half bridge sub-module (HBSM) has reliable performance in DC fault ride-through capability and is receiving more and more attention. Due to the different charging characteristics of FBSM and HBSM, the sub-modules (SMs) capacitor voltages may be different at the end of the uncontrolled precharging process. This paper introduces conventional uncontrolled precharging strategy of the hybrid MMC and points out the problems in the process. Then a three-stage precharging strategy is proposed in this paper. This strategy can eliminate the capacitor voltages imbalance of different SMs and solve the problem of unsuccessful self-taking energy of HBSM during precharging process. Finally, simulation and analysis of the uncontrolled precharging process based on the proposed strategy are carried out.