考虑功率裕度的MMC-MTDC改进下垂平坦控制策略  

MMC-MTDC improved droop flat control strategy considering power margin

作　　者：宋平岗 杨长榄 龙日起 雷文琪 郑雅芝 SONG Ping-gang;YANG Chang-lan;LONG Ri-qi;LEI Wen-qi;ZHENG Ya-zhi(School of Electrical and Automation Engineering, East China Jiaotong University, Nanchang 330013, China)

机构地区：[1]华东交通大学电气与自动化工程学院,江西南昌330013

出　　处：《电工电能新技术》2021年第6期22-31,共10页Advanced Technology of Electrical Engineering and Energy

基　　金：国家自然科学基金项目(51367008)。

摘　　要：针对基于模块化多电平换流器的多端直流输电系统(MMC-MTDC)功率协调控制和直流电压稳定问题,在改进下垂控制的基础上引入微分平坦控制(FBC)理论,提出一种考虑功率裕度的改进下垂平坦控制策略。该策略考虑不同工况下下垂控制站的实时功率裕度,根据各换流站裕度大小来合理分担系统中存在的不平衡功率,避免换流站满载。同时引入微分平坦控制理论设计电流内环控制器,替代传统电流内环的直接电流控制。控制器由期望前馈控制和误差反馈补偿两部分组成,前馈控制产生主导控制量,误差反馈补偿消除系统模型不确定性和内外部扰动等因素造成的影响,对控制量进行修正,准确跟踪期望值,有效提高了系统响应速度。以一个并联四端MMC-MTDC系统为例的仿真结果说明了所提控制策略的有效性。Aiming at the power coordinated control and DC voltage stability of the multi-terminal direct current transmission system(MMC-MTDC)based on modular multilevel converters,the differential flat control(FBC)theory is introduced on the basis of improved droop control,and an improved droop flatness control strategy is proposed with consideration of power margin.The strategy considers the real-time power margin of the droop control station under different operating conditions,and reasonably shares the unbalanced power in the system according to the margin of each converter station to avoid the converter station being fully loaded.At the same time,the differential flat control theory is introduced to design the current inner loop controller to replace the direct current control of the traditional current inner loop.The controller consists of two parts:expected feedforward control and error feedback compensation.Feedforward control produces the dominant control quantity,and error feedback compensation eliminates the influence of system model uncertainty and internal and external disturbances,and corrects the control quantity to accurately track the expected value effectively,that improves the system response speed.Taking a parallel four-terminal MMC-MTDC system as an example,the simulation results show the effectiveness of the proposed control strategy.

关 键 词：模块化多电平换流器 多端直流输电 改进下垂 微分平坦控制理论 功率裕度 

分 类 号：TM7[电气工程—电力系统及自动化]