一种新型电力机车牵引换流器设计

摘要

针对传统交直交电力机车牵引系统存在主电路结构复杂、功率和电压水平受限等问题,基于采用全桥型子模块的模块化多电平换流器结构,设计了一种单相AC-三相AC电力机车牵引换流器,可直接驱动三相异步牵引电动机,从而取消了车载降压变压器,降低了电力机车牵引系统的复杂度.通过建立该换流器在两相同步旋转dq坐标系的数学模型,提出了一种外环定交流电压控制策略和内环直接电流控制策略.仿真结果验证了该换流器及控制策略的有效性.%In view of problems of complex structure of main circuit and limited power and voltage existed in traditional traction system of AC-DC-AC electric locomotive,a traction converter for electric locomotive with single-phase AC input and three-phase AC output was designed based on structure of modular multilevel converter using full bridge sub-module.The traction converter can drive traction motor directly,so as to eliminate vehicle-mounted step-down transformer and reduce complexity of traction system of electric locomotive.A constant AC voltage control strategy in outer loop and direct current control strategy in inner loop was proposed according to mathematic model of the converter established in two-phase synchronous rotating dq coordinate system.The simulation results verify validity of the converter and the control strategies.