Magnetic-Integrated Multipulse Rectifier Transformer With a Tight Impedance Equalizing Strategy for Power Quality Improvement of DC Traction Power Supply System

To improve the power quality of dc traction power supply system (DC-TPSS), a magnetic-integrated multipulse rectifier transformer (MI-MPRT) with a tight impedance equalizing strategy is proposed in this article. The configuration and winding-arrangement of MI-MPRT are introduced, and by integrating multiple windings on a same iron core, the volume and cost of the proposed transformer can be decreased significantly. Cooperated with the staggered winding-arrangement, a tight impedance equalizing strategy is proposed to optimize the winding thickness and insulation distance comprehensively, and MI-MPRT would be designed in a minimum axial dimension, with equalizing short-circuit impedance of each winding. A high-power prototype is manufactured, and the efficiency of prototype is verified by the transformer standard test. In addition, the DC-TPSS based MI-MPRT is implemented, and the experiment results validate that the power quality of new system can be improved significantly by harmonic elimination, circulation-currents suppression, and dc-voltage ripple restraint. Both the theoretical and experimental results indicate that the proposed MI-MPRT is suitable for power quality improvement and industrial application in DC-TPSS.