摘要
模块化多电平换流器(modular multilevel converter,MMCs)的高可靠性是确保整个柔性化直流输电系统安全可靠运行的关键。由于实际MMC系统受风能等新能源的随机性、间歇性影响,IGBT结温长期处于剧烈波动状态,常规电力电子设备可靠性评估方法已无法满足换流器设计的高可靠性要求。文中提出一种考虑任务剖面的MMC系统可靠性评估方法。首先,基于实测风速数据分析风电场接入的25MW MMC系统运行工况下一年的输出功率,同时在功率器件结温预测中考虑基频结温波动的影响;通过雨流算法进行热荷载统计,以便于应用寿命模型,从而得到功率器件静态累积损伤。考虑寿命模型参数和器件参数的随机性和波动性,采用Monte-Carlo仿真建立器件寿命分布模型;以子模块中器件级可靠性分析为基础,通过可靠性方框图建立系统级可靠性模型,进而对不同冗余子模块的MMC系统进行可靠性分析。研究结果表明,本方法可为MMC系统可靠性量化评估和系统高可靠性设计提供理论指导。
The high reliability of modular multilevel converter(MMC)is the key to ensure the safe and reliable operation of the flexible HVDC transmission system.IGBT junction temperature is in a state of violent fluctuation for a long time,because the actual MMC system is affected by the randomness and intermittence of new energy such as wind energy.Conventional reliability assessment methods for power electronic equipment cannot meet the high reliability requirement of converter designs.This paper proposes a reliability assessment method for the MMC system based on the mission profile.Firstly,the annual output power of the 25 MW MMC system with the wind farm was analyzed under the actual wind speed data.The influence of junction temperature fluctuation at fundamental frequency was taken into account in the junction temperature prediction.The rain-flow counting was used to calculate the thermal loadings,so as to apply the lifetime model and get the static cumulative damage of power devices.Considering the randomness and fluctuation of lifetime model parameters and device parameters,Monte-Carlo simulation was used to establish lifetime distribution model of devices.Based on the device level reliability analysis in the sub-module,the reliability model of the system level was established through the reliability block diagram.Then,the reliability analysis was carried out for the MMC system with different redundancy sub-modules.The results show that the proposed method can provide guidance for the quantitative reliability assessment and high reliability design of MMC system.
作者
王希平
李志刚
姚芳
WANG Xiping;LI Zhigang;YAO Fang(State Key Laboratory of Reliability and Intelligence of Electrical Equipment,Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province(Hebei University of Technology),Hongqiao District,Tianjin 300130,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2021年第7期2495-2506,共12页
Proceedings of the CSEE
基金
国家自然科学基金项目(51377044)
河北省自然科学基金重点项目(E2017202284)
河北省自然科学基金项目(E2019202481)。
