基于改进型单周控制的MMC系统三相不平衡控制法
摘要：为了应对模块化多电平(MMC)系统在三相电网不平衡条件下的运行,本文提出了一种改进型单周控制法,在基本单周控制的基础上使用网侧负序电压来补偿MMC网侧电流反馈量,避免了三相电流的正负序转换运算。同时加入虚拟循环映射方案进行子模块电容均压。本方法相比现有的MMC不平衡控制策略,简化了控制环节,参数设计较为容易。三相电压跌落仿真结果表明,本文提出的控制方法不仅能够实现MMC在三相不平衡时的单周控制,降低直流电压中两倍于基频的谐波,使电网输出的有功功率趋于稳定,而且可以使子模块电容电压自动达到均衡,减少了系统的器件损耗。
Abstract:In order to deal with the operation of modular multilevel converter (MMC) system under the condition of unbalanced three-phase condition, this paper proposes an improved one-cycle-control method, which uses the negative grid-side voltage to compensate the current feedback of the MMC grid-side based on basic one-cycle-control, to avoid the positive and negative sequence transformation calculation of three-phase current. Moreover, virtual loop mapping scheme is added to balance sub-module capacitor voltages. Compared with the existing MMC unbalanced control strategy, control process is simplified and parameter design is relatively easy. The simulation results of three-phase voltages dip show that the proposed method can not only realizes one-cycle-control of MMC under three-phase unbalance condition, reduces the twice fundamental-frequency harmonics in the DC voltage, and makes the output active power of the grid more stable, but also it is able to make the submodule capacitor voltages automatically reach the balance, which reduces device loss of the system.
标题：基于改进型单周控制的MMC系统三相不平衡控制法
英文标题：Three-phase Unbalanced Control Method of MMC System Based on Improved One-cycle-control
作者：丁然, 梅军, 赵剑锋, 缪惠宇, 王创, 管州, 田杰,
关键词：模块化多电平, 三相不平衡, 单周控制, 负序电压, 虚拟循环映射,
发表日期：2018-12-09
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- 4.1 MB
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