基于MMC的直流电网分层能量平衡控制  

Hierarchical Energy Balance Control for MMC-based DC Grid

作　　者：阎发友 汤广福 贺之渊 孔明 安婷 

机构地区：[1]中国电力科学研究院,北京市海淀区100192 [2]先进输电技术国家重点实验室(全球能源互联网研究院),北京市昌平区102209

出　　处：《中国电机工程学报》2016年第21期5757-5764,6018,共8页Proceedings of the CSEE

基　　金：国家电网公司科技项目(SGRIZLKJ[2015]457)~~

摘　　要：直流电网的瞬时能量平衡控制是其安全稳定运行的关键。当前,研究人员在进行直流电网的能量平衡控制策略设计时,重点关注了换流器之间的功率平衡控制,而忽视了换流器内部的瞬态能量平衡控制,因此无法满足直流系统暂稳态能量在较小时间尺度上进行平衡调控的要求。以基于模块化多电平换流器(modular multilevel converter,MMC)的直流电网为研究对象,重点对MMC的内部瞬态能量平衡控制进行了研究。首先,从MMC桥臂瞬时功率转移出发,对MMC的换流过程进行了分析;然后,以不同换流回路瞬态能量平衡为控制目标,分别提出了基于子模块电容能量平均值反馈控制和波动值预估控制策略;最后,通过PSCAD电磁暂态仿真,验证了所提出方法的有效性。The key to maintain secure and stable operation of DC grid is to keep the instantaneous energy balance of DC system. Considering the energy balance control strategy, the literatures more focus on the energy balance control among converters while ignoring the instantaneous energy balance control inside the converter. This paper, considering the modular multilevel converter（MMC） based DC grid, investigateed the energy balance control inside MMC. Firstly, according to energy transfer in the arms, it analyzed the commutation process of the MMC. Then according the relationship between the submodule（SM） voltage and instantaneous energy flow in the arms, a control strategy to regulate the SM voltage was proposed to maintain the energy balance in the MMC. A hierarchical energy control architecture for DC grid was proposed by combining the system level energy control and internal energy balance control of MMC. The simulation results verified the effectiveness of the proposed control methodology.

关 键 词：直流电网 模块化多电平换流器 换流过程 能量平衡控制 子模块电压控制 

分 类 号：TM72[电气工程—电力系统及自动化]