电力机车PET中直流母线电压的大信号建模及分析

为了准确分析电力电子变压器在大信号扰动下的动态特性,给出一种基于功率平衡的回转器建模方法。利用该方法对额定容量为3 MW的电力电子变压器进行了建模,并与传统的开关模型进行了比较分析。仿真结果表明,基于功率平衡的回转器建模方法具有实用性和有效性。该模型不仅可以精确反映系统在大信号扰动下的行为特性,而且可以减低仿真时间。为了实现前后级直流母线电压的解耦控制,提出了电压前馈补偿策略。在此基础上,建立了母线电压的统一时域解析方程,定量分析了在大信号扰动下系统参数对各直流母线电压的影响,给出了关系曲线,为各模块控制器的设计提供了准则。

Large signal modeling and analysis of DC-bus voltage of power electronic transformer applied in electric locomotive

In order to accurately analyze the dynamic characteristics of Power Electronic Transformers (PET) under large signal disturbances, a new rotator modeling method based on power balance is proposed. This method is used to model the PET with rated capacity of 3 MW and compared with the traditional switch model. The simulation results show that the proposed model has validity and practicality. It can not only accurately reflect the behavior of the system under the disturbance of large signal, but also can reduce the simulation time. In order to realize the decoupling control of the front and rear DC bus voltage, a voltage feedforward compensation strategy is proposed. On this basis, a uniform time domain analytic equation of bus voltage is established, the influence of system parameters on DC bus voltage under large signal perturbation is quantitatively analyzed, and the relation curve is given, which provides the criterion for the design of each module controller. This work is supported by National Natural Science Foundation of China (No. 51567009), Natural Science Foundation of Jiangxi Province (No. 20181BAB206033) and Cultivate Plan for Application Research of Jiangxi Province (No. 20181BBE58008).