[关键词]
[摘要]
为进一步降低铁路功率调节器在大功率补偿过程的开关频率,采用开关频率较低的混合级联81电平变换器作为电压源、开关频率较高的单相全桥变换器作为电流源,将两个电压源背靠背连接,提出一种81电平铁路功率调节器。由于系统中承担85%的补偿功率的开关器件的开关频率在250 Hz及以下,开关频率高的电流源仅承担1%的功率,因此系统开关损耗小且对补偿电流参考信号的跟踪性能好。研究了系统的基本结构及其等效电路,通过构建等效对称三相电压源建立等效三相电路,采用有功功率平均分配法,使得补偿后的系统等效为Y-Y型对称三相电路,从而实现不平衡电流补偿,并提出一种新的补偿电流检测方法。仿真结果证明所提系统及其补偿方法的有效性和可行性。
[Key word]
[Abstract]
In order to reduce the switching frequency of railway power conditioner in the process of high power compensation, a hybrid cascade 81-level converter with low switching frequency is used as the voltage source and a single-phase H bridge converter with high switching frequency is used as the current source. The two voltage sources are connected back-to-back, and an 81-level railway power conditioner is proposed. Since the switching frequency of the switching devices that bear 85% of the compensation power in the system is 250 Hz and below, and the current sources with high switching frequency only bear 1% of the power, the system has small switching loss and good tracking performance for the compensation current reference signal. The basic structure of the system and its equivalent circuit is studied, the equivalent three-phase circuit is established by constructing the equivalent symmetrical three-phase voltage source, the active power average distribution method is used to make the system equivalent to Y-Y symmetrical three-phase circuit, so that the imbalance compensation is realized, and a new compensation current detection method is put forward. Simulation results show the effectiveness and feasibility of the proposed system and its compensation method.
[中图分类号]
[基金项目]
湖北省技术创新专项重大项目(2019AAA018)