Adaptive droop control for better current-sharing in VSC-based MVDC railway electrification system

• 作者: Haitao HU Salman AATIF Shibin GAO Xiaowei YANG Yinbo GE Zhengyou HE
• 来源期刊: 现代电力系统与清洁能源学报(英文)
• 学科: 交通运输
• 关键词: Railway ELECTRIFICATION Voltage source converter(VSC) Medium-voltage direct current(MVDC) Current-sharing RENEWABLE ENERGIES in railways
• 年，卷（期）: 2019,（4）
• 页码范围: 962-974
• 页数: 13页
• 分类号: U223

摘要

The share of voltage source converter(VSC)technology is increasing in conventional power systems,and it is penetrating into specific transportation systems such as electric vehicles,railways,and ships.Researchers are identifying feasible methods to improve the performance of railway electrification systems(RESs)by utilizing VSC-based medium-voltage direct current(MVDC)railways.The continuous motion of electric trains makes the catenary resistance a variable quantity,as compared to the traction substation(TSS),and affects the currentsharing behavior of the system.A modified droop control technique is proposed in this paper for VSC-based MVDC RES to provide more effective current-sharing while maintaining catenary voltages above the minimum allowable limit.The droop coefficient is selected through an exponential function based on the ratio between the concerned TSS current and the system average current.This enables small adjustments of droop values in less concerning marginal current deviations,and provides higher droop adjustments for large current deviations.Meanwhile,the catenary voltages are regulated by considering the voltage data at the midpoint between two TSSs,which experiences the lowest voltages owing to the larger distance from the TSSs.The proposed techniques are validated via simulations and experiments.