Closed-Loop Precharge Control of Modular Multilevel Converters During Start-Up Processes

Author

Binbin Li ; Dandan Xu ; Yi Zhang ; Rongfeng Yang ; Gaolin Wang ; Wei Wang ; Dianguo Xu

Author_Institution

Sch. of Electr. Eng. & Autom., Harbin Inst. of Technol., Harbin, China

Volume

30

Issue

2

fYear

2015

fDate

Feb. 2015

Firstpage

524

Lastpage

531

Abstract

This letter respectively presents two closed-loop precharge control methods to fully charge the submodule (SM) capacitors of the modular multilevel converter (MMC) during dc-side and ac-side start-up processes. The proposed methods are aimed at regulating a constant charging current thus reducing the start-up time and eliminating the inrush current. Besides, capacitor voltage balancing control is also embedded into the controller to equally charge the SM capacitors. Due to the flexibility of the closed-loop control, these methods are applicable to any MMC applications regardless of the number of SMs. Finally, effectiveness of the proposed methods is verified experimentally on a three-phase prototype of MMC.

Keywords

closed loop systems; power capacitors; power convertors; voltage control; MMC; SM capacitors; ac-side start-up process; capacitor voltage balancing control; closed-loop precharge control; constant charging current regulation; dc-side start-up process; modular multilevel converters; submodule capacitors; Capacitors; Converters; Process control; Prototypes; Switches; Voltage control; Voltage measurement; Closed-loop precharge control; modular multilevel converter (MMC); start-up scheme;

fLanguage

English

Journal_Title

Power Electronics, IEEE Transactions on

Publisher

ieee

ISSN

0885-8993

Type

jour

DOI

10.1109/TPEL.2014.2334055

Filename

6846354