基于模块化结构的电气化铁路统一电能质量控制器

A Railway Unified Power Quality Controller Based on Modular Structure for Electric Railway

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 main circuit topologies suitable for the railway power quality controller （RUPQC） based on the modular structure are proposed. They both have a cascaded structure on the alternating current （AC） side with low level harmonics. To solve the capacitor voltage balance problem in the cascaded converter, a mathematic model of direct current （DC） capacitor voltage in the proposed topologies are deduced. The advantages, disadvantages and application of existing balancing methods for back-to：back ＇converters are analyzed, which have bidirectional real power flow. The results show that the DC component of capacitor voltage has positive correlation and negative correlation with modulation rations of absorbed and emitted active power respectively. In the end, the control scheme of RUPQC devices is given, the effectiveness of the topologies and control algorithm proposed is verified by simulation examples.