功率耦合与阻感比结合的MMC-RPC新型下垂控制策略

并联在牵引供电臂上的铁路功率调节器RPC(railway power conditioner)与供电臂间的连接线路上会产生电能损耗,使得RPC无法对牵引网中的电能达到有效、精准的治理效果。以采用模块化多电平换流器结构的铁路功率调节器MMC-RPC(modular multilevel converter-rail power conditioner)为研究对象,对其进行建模,推导出其交流侧P-f与Q-U之间的关系,建立传统的下垂控制方式。在此基础上考虑传输线路的阻感影响,提出一种改进型的下垂控制策略,它采用功率耦合的方式,并引入阻感比参数,它能更加灵活有效地跟踪MMC-RPC的期望出功率。最后在MATLAB\Simulink中模拟实际工况对MMC-RPC系统进行仿真,仿真结果验证了所提下垂控制策略对于MMC-RPC系统的有效性;与传统下垂控制的仿真结果相对比,进一步说明了这种改进方式的优越性。

Novel Droop Control Strategy of MMC-RPC with the Combination of Power Coupling and Resistance Ratio

Energy loss will occur on the transmission line between the railway power conditioner(RPC) and power su-pply arm, which makes the RPC cannot achieve the effective and accurate control of power quality in the traction network. In this paper, the RPC with a structure of modular multilevel converter(MMC-RPC) is adopted as the research object, and its model is built. Afterwards, the P-f and Q-U relationships on AC side are derived, and a traditional droop control mode is established. On this basis, the influence of the transmission line''s resistance is considered, and an improved droop control strategy is proposed:the power coupling method is used with the introduction of resistance ratio, which can track the expected power of MMC-RPC more flexibly and effectively. At last, the MMC-RPC system working under the actual working conditions is simulated in MATLAB/Simulink, and simulation results prove that the proposed droop control strategy is effective for the MMC-RPC system; moreover, the comparison of simulation results with the traditional droop control further indicates the advantage of the improved method.