基于电子电力变压器的自平衡牵引变压器

Auto-balancing Traction Transformer with Electronic Power Transformer

为了减小电力牵引系统对电网的负面影响,基于电子电力变压器的设计思路,研究设计了一种具有自平衡能力的牵引变压器。通过采用级联多电平技术和交错并联技术,既较好地解决了电力电子开关器件的电压和电流定额与配电系统匹配问题,又同时解决了阻止向一次侧电网注入负序分量问题;设计的牵引变压器采用基于载波移相技术的控制方案即网侧采用功率因数可调的解耦双闭环直接电流控制,负荷侧采用确保各相输出电压独立恒定的相间独立的电压有效值反馈控制。用Matlab/Simulink环境下建立模型的仿真结果表明:所提出的自平衡牵引变压器无论二次侧两相负荷是否一致,都可保证一次侧三相电流对称,并减小了负载谐波对电网的污染。

An auto-balancing traction transformer （ATT） was proposed. In the proposed ATT, the cascaded multilevel converter technology and interleaving parallel technology were used to solve the matching problem about the rated voltage and current of power electronic device and power system. At the same time, this also can prevent the negative sequence component from injecting into the power system. And a simple effective control method based on triangle carrier phase-shifted technique was designed. In the proposed control scheme, the state feed back decoupling and voltage feed forward were applied to the primary side to achieve the power factor adjustment, and the RMS value of the output voltage feed back was adopted for every phase to obtain the output voltage constant. The simulation system was established in Matlab/Simulsink, and computer simulations were performed to verify the performance of the proposed ATT. The simulation results show that the proposed ATT can keep the primary side system auto-balancing even if the loads of the two output phases were different, and features excellence in harmonic suppression.