输电系统中并网变流器优化双向功率稳定性差异的阻抗控制策略  

Impedance Control Strategy for Optimizing Bidirectional Power Stability Difference of Grid-connected Converters in Transmission System

作　　者：田艳军 彭飞[1] 王慧[1] 王毅[1] 官仕卿 TIAN Yanjun;PENG Fei;WANG Hui;WANG Yi;GUAN Shiqing(Hebei Key Laboratory of Distributed Energy Storage and Micro-grid,North China Electric Power University,Baoding 071003,China)

机构地区：[1]华北电力大学河北省分布式储能与微网重点实验室,保定071003

出　　处：《高电压技术》2020年第11期3734-3742,共9页High Voltage Engineering

基　　金：国家自然科学基金(51707067);中央高校基本科研业务费专项资金(2017MS098)。

摘　　要：交直流混合输电线路中功率面临双向流动的情况,功率正向与反向之间系统稳定性存在明显的差异特性,即双向功率稳定性差异。论文针对交直流混合输电系统中并网变流器双向功率稳定性差异进行研究。为了解决双向功率稳定性差异,进而提高的系统稳定性,首先对功率控制的逆变器交流侧阻抗在d-q坐标系下进行小信号建模,对比分析正向和反向功率下的阻抗特性。其次,结合阻抗稳定判据,揭示双向功率流动对并网变流器系统稳定性造成的影响。然后,提出了一种阻抗优化控制策略,在不改变稳定性较好的正向阻抗特性的同时,优化并统一反向阻抗特性。最后,通过Matlab/Simulink仿真模型对所提出控制策略的有效性进行了验证。研究结果表明:优化后的变流器系统在双向功率流动下,能够保持较为统一的稳定特性,并能够有效抑制传输功率传输方向变化引起的振荡问题。研究结果证明了所提控制策略的有效性。Bidirectional power flow occurs in AC/DC hybrid transmission network. There is a significant difference in system stability between the forward and reverse power flow, that is, the bidirectional power stability difference. In this paper, the bidirectional power stability difference of grid-connected converters in AC/DC hybrid transmission systems is studied. In order to solve the problem of bidirectional power stability difference and improve the system stability, through small-signal modeling of AC-side impedance of power-controlled inverter in d-q frame, the impedance characteristics of forward and reverse power flow are compared, firstly. In addition, combined with the impedance stability criterion, the stability difference of the grid-connected converter system caused by the bidirectional power flow is revealed. Moreover, an impedance optimization control strategy is proposed. Without changing the forward impedance characteristics, the reverse impedance characteristics are optimized and unified. Finally, the effectiveness of the proposed control strategy was verified by the Matlab/Simulink simulation model. The results show that the converter system can maintain a relatively uniform stability characteristic under the bidirectional power flow, and the oscillation problem caused by the change of the power transmission direction can be effectively suppressed at the same time. The research results prove the effectiveness of the proposed strategy.

关 键 词：功率双向流动 并网逆变器 稳定性 阻抗 交直流混合输电 功率控制 优化控制 

分 类 号：TM46[电气工程—电器]