基于级联型多电平变换器的贯通式同相供电系统关键控制策略研究

The continuous cophase power supply system, which is composed of the novel cophase power supply devices without traction transformers with cascaded multilevel structure, can improve the power quality of the traction power supply system and results in the elimination of electric phase separation. To deal with the input voltage fluctuation, sudden load change and the double-frequency ripple of DC link voltage in the power supply system, the full-disturbance-suppression control strategy for the rectifier stage will be investigated in this project, which will improve the input current quality and dynamic responses. To deal with complex working conditions of locomotives, a high performance multi-loop hybrid control strategy without current loop for the inverter stage will be investigated, which can suppress the output voltage fluctuation and distortion of single cophase power supply device to ensure the stable power supply. Through analyzing the parallel target of multiple novel cophase power supply devices, a parallel control strategy with active circulating current suppression and nearby power supply will be proposed in order to construct continuous cophase power supply system. For the novel cophase power supply devices, a FPGA based power electronics digital control system design theory will be studied in order to realize the quazi-analog circuit characteristic of digital system and improve the control system performance under low switching frequency. In this project, the issues relating to high speed, heavy load and green operation of electric locomotives are attempted to be solved, the basic theories and key technologies for novel cophase power supply system through engineering application are introduced for the purpose to furthur improve the international competitiveness of electrified railway equipment of our country.

贯通式同相供电系统由采用级联型多电平结构的无牵引变压器新型同相供电装置构成，可有效改善现有牵引供电系统电能质量、彻底取消电分相。围绕该供电系统，本课题针对功率单元输入电压畸变、负载突变及直流母线电压二倍频波动，研究功率单元整流侧全扰动抑制控制策略，提高其输入电流质量及系统动态性能；针对机车复杂运行工况，提出一种无电流环高性能多环复合逆变控制策略，可抑制单台同相供电装置输出电压波动与畸变，确保其稳定供电；通过分析多台新型同相供电装置的并联目标，提出一种具有就近供电与环流主动抑制能力的并联控制策略，从而构建无电分相贯通式供电系统；针对新型同相供电系统，研究FPGA电力电子数字控制系统设计理论，实现数字系统准模拟电路特性，提高低开关频率下系统性能。本课题力图解决制约电力机车高速、重载及绿色运行的问题，为贯通式新型同相供电系统工程应用提供基础理论和关键技术，进一步提升我国电气化铁路装备国际竞争力。

我国电气化铁路采用单相工频牵引供电系统，负序和电分相是其存在的主要问题。贯通式同相供电系统由采用级联型多电平结构的无牵引变压器新型同相供电装置构成，可有效改善现有牵引供电系统电能质量、彻底取消电分相。围绕该供电系统，项目针对功率单元输入电压畸变、负载突变及直流母线电压二倍频波动，研究功率单元整流侧全扰动抑制控制策略，提高其输入电流质量及系统动态性能；针对机车复杂运行工况，研究无电流环高性能多环复合逆变控制策略，抑制单台同相供电装置输出电压波动与畸变；通过分析多台新型同相供电装置的并联目标，研究具有就近供电与环流主动抑制能力的并联控制策略，从而构建无电分相贯通式供电系统；针对新型同相供电系统，研究FPGA电力电子数字控制系统设计理论，实现数字系统准模拟电路特性，提高低开关频率下系统性能。项目提出了一种基于电压电流双闭环的功率单元整流侧全扰动抑制控制策略，设计了消除直流母线电压二倍频波动、提取直流母线电压直流分量的无延时自适应状态观测器，并基于李雅普诺夫稳定性判据证明其稳定性和渐近收敛性；提出了新型同相供电装置逆变侧的无电流环高性能多环复合控制策略，抑制机车负载剧烈变化造成的接触网电压波动与畸变，提高供电系统可靠性；提出了一种基于单相虚拟同步机的多台新型同相供电装置无互联线电压源并联控制策略，具有就近供电与环流主动抑制能力，彻底取消电分相，实现牵引网贯通式供电；提出了具有指导意义的FPGA全数字电力电子控制系统的一般设计原则、设计方法与设计流程，形成了FPGA电力电子变换器控制架构设计理论，构建了FPGA全数字电力电子控制硬件平台。项目研究结果力图解决制约电力机车高速、重载及绿色运行的问题，可为新型同相供电系统的实际工程应用奠定理论基础，亦为电气化铁路牵引供电系统安全、可靠、节能运行提供有力的技术支撑。同时，项目所形成的控制策略与理论体系，也可应用于我国的城市轨道交通供电系统，进一步提高节能降耗的效果。