双星型多电平组合式同相供电系统分析

为实现电气化铁路牵引电力系统三相电流平衡,将双星型多电平变换器DSMC应用于单、三相组合式同相供电系统中,该系统可以省去常规补偿结构中昂贵的耦合降压变压器。对DSMC的等效模型进行分析计算,通过控制4个桥臂的调制系数来控制各桥臂的电流。针对DSMC的结构,提出一种上层电流控制、下层功率子模块投入切除控制的两级分层控制策略,保证了系统的安全稳定运行。最后通过搭建Matlab/Simulink模型并进行仿真,验证了理论分析的正确性和控制策略的有效性。

Analysis of Double-star Multilevel Combined Co-phase Power Supply System

To realize a three-phase current balance in an electrified railway traction power system , a double-star multi-level converter ( DSMC ) is applied to a single-phase three-phase combined co-phase power supply system , which can save the cost of a coupling step-down transformer used in the conventional compensation structure. The equivalent mod-el of DSMC is analyzed and calculated to control the current of each leg arm by controlling the modulation coefficients of the four leg arms. According to the structure of DSMC , a two-level hierarchical control strategy is put forward , which consists of upper-layer current control and cutoff control of the lower-layer power sub-module. In this way , the safe and stable operation of the system is guaranteed. Finally , a simulation model is built in Matlab/Simulink , and simulation re-sults verify the correctness of the theoretical analysis and the effectiveness of the control strategy.