摘要
MMC-HVDC相间环流使得桥臂电流发生畸变,增大了桥臂电流峰值,增加了功率损耗,并严重威胁子模块电容电压平衡和电容的寿命。为此,本文首先分析MMC-HVDC的工作原理和数学模型,进一步分析了MMC相间环流产生机理,分析表明环流中只存在偶数次谐波,不存在奇数次谐波,其中,2、4、6次环流谐波含量所占比重最大。基于此提出了一种基于准PR控制器的新型环流抑制策略。该控制策略不仅克服了传统PR控制器抗电网频率偏移能力差、带宽窄的缺点,而且大大减少了准PR控制的使用数量,减小了系统设计的复杂度。仿真和实验结果验证了所提出控制策略的正确性和优越性。
The distortion of bridge arm current is caused by the interphase loop current between MMC and HVDC,causing increase of peak of bridge arm current and of power loss and threating seriously balance of capacitive of sub-model and life of capacitor. Therefore, in this paper, the operating principle and mathematical model of MMC-HVDC is analyzed and the generation mechanism of inter-phase loop current of MMC is analyzed further. It is shown by the analysis that in the loop current there is no odd number harmonics but even number harmonics,in which the harmonic contents of 2nd,4th and 6th loop current are the largest proportion. On this basis,a new type loop current control strategy based on quasi- PR controller is proposed. This control strategy not only overcomes such disadvantage of tradi-tional PR controller as weak shift ability in resisting grid frequency and narrow wideband,but also reduces the application quantity of quasi-PR control and reduces the complexity of system design. Both the correctness and superiority of the proposed control strategy is verified by the simulation and experimental results.
出处
《电力电容器与无功补偿》
北大核心
2016年第4期87-94,共8页
Power Capacitor & Reactive Power Compensation
基金
国家自然科学基金项目(51107070)
