提高扰动下VSC-HVDC供电电压质量的逆变站控制方法  

Enhancement of Voltage Quality in a Passive Network Supplied by a VSC-HVDC System Under Disturbances

作　　者：唐欣[1] 李建霖[1] 滕本科[1] 

机构地区：[1]长沙理工大学电气与信息工程学院,长沙410000

出　　处：《电工技术学报》2013年第9期112-119,共8页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51277013)

摘　　要：无源网络由VSC-HVDC供电时,由于逆变站的输出电抗较大使得受端系统扰动下易遭受电压跌落和电压浪涌问题。为提高VSC-HVDC向无源网络供电的电压质量,本文提出一种高动态性能的逆变站电压控制方法。首先基于逆变站的数学模型针对负载电流对电压的影响设计了前馈补偿器,并进一步讨论了逆变器非线性特性对前馈补偿性能的影响,进而在dq坐标下提出逆变器的非线性补偿方法。此外,为了克服前馈补偿的参数敏感特性,引入了PI反馈控制。利用PSCAD/EMTDC的软件在几类系统扰动下对提出的控制方法与直接电压控制方法、传统的前馈补偿方法进行了仿真比较。结果表明,提出控制方法能有效提高扰动下VSC-HVDC供电的电压质量。The received system is weak and subject to voltage quality problems such as voltage sag and swell when a VSC-HVDC transmission ~s connected to a passive network. Then, dynamic performance of voltage control directly affects voltage quality in received system and particular care is required in the design of the controller. This paper presents a voltage vector control scheme without an inner current loop to enlarge control bandwidth. In the proposed control scheme, a feed-forward controller is used to reject abruptly changing load current. The influence of inverter nonlinearities on the performance of the feed-forward controller is further discussed. A compensation method for nonlinearities of the inverter is designed in dq rotating axis. Moreover, to overcome parameter sensitivity of the feed-forward controller, a feed-back loop with a PI controller is implemented. Simulations using PSCAD/EMTDC were carried out to show the proposed control scheme under various system disturbances. The simulation results show that with the use of the proposed control scheme, as compared with the direct voltage control, the VSC-HVDC system has a better capability to mitigate voltage fluctuation during system disturbances.

关 键 词：交流电压控制 电压质量 非线性补偿 柔性直流输电 

分 类 号：TM732[电气工程—电力系统及自动化]