一种模块化级联H桥构造的三相—单相同相牵引供电系统

为解决高速、重载电气化铁路负序、谐波和无功等电能质量问题,依据三相对称补偿理论,并结合H桥构造,提出了基于模块化级联H桥的三相—单相同相牵引供电系统。分析了系统补偿特性及工作原理,研究了直挂型"!"联结的有源补偿装置(MMCHC)拓扑结构,推导了子模块参数确定方法,并给出了系统控制策略。通过直挂补偿装置将三相牵引变压器转换为单相供电,节省了匹配变压器的容量为补偿容量的2倍。仿真表明,补偿装置在牵引和再生制动工况下均具备良好的补偿特性和动态性能,消除了牵引负荷引起的负序、谐波和无功分量,且子模块电容电压稳定在2%以内。

Three-phase to single phase co-phase traction power supply system based on modular multilevel cascaded H-bridge

In order to solve the power quality problems such as negative sequence,harmonic and reactive power for high-speed and heavy-loading railway, on the basis of 3-phase symmetrical compensation and H-bridge,a co-phase traction power supply structure of 3-phase to single-phase is presented by combining the modular multilevel cascaded H Bridge compensator(MMCHC)with the universal 3-phase transformer. The compensative principles and characteristic were analyzed respectively.The topology of MMCHC by delta arms connection was proposed,the sub-module parameters were designed, and the control strategy was also given subsequently.The 3-phase traction transformer is converted into single-phase power supply by the direct-connected compensation device,then the saved capacity of deleting matched transformers is 2 times of the compensation capacity.Simulations show that the compensation characteristics and dynamic performance is prominent for the compensator in traction and regenerative braking operation condition. Negative sequence,harmonic and reactive power can be eliminated, and the sub-module capacitor volt-age is stabilized within 2%.