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提出了2种基于模块化结构的铁道统一电能质量控制器主电路拓扑,2种拓扑交流侧均采用链式结构,具有良好的谐波特性。针对链式结构变流器存在的直流电压平衡问题,建立了所述拓扑中电容电压的数学模型,并对现有各种直流电压平衡控制策略的优缺点及存在有功功率双向流动的背靠背变流器的适用性进行了分析。结果表明,电容电压中的直流分量分别与吸收和发出有功功率侧变流器的调制比成正相关和反相关的关系。最后,给出了铁道统一电能质量控制器装置级控制策略,并通过仿真实例证明了所述拓扑和控制策略的正确性。
Two kinds of main circuit topology of railway unified power quality controller based on modularized structure are proposed. Both topological AC sides adopt chain structure and have good harmonic characteristics. Aiming at the problem of DC voltage balance existing in the chain structure converter, a mathematical model of the capacitor voltage in the topology is established, and the advantages and disadvantages of the existing DC voltage balance control strategies and the existence of back-to-back converter with active power bidirectional flow Applicability of the device was analyzed. The results show that the direct current components in the capacitor voltage have a positive and negative correlation with the modulation ratio of the active power-side converter. Finally, a device-level control strategy of a railway unified power quality controller is given, and the correctness of the topology and control strategy is proved through simulation examples.