Research On High-Power AC Drive Locomotive Traction Converter

Locomotive DC dive upgrading to AC drive has been completed after 30 years of research, assessment, technology updating in western developed countries. IEC, Shinkansen, TGV have been the important symbol of railway modernization and comprehensive national strength in those countries. AC drive has been the only choice of high-speed and heavy railway. Comparing with foreign countries, Chinese AC Drive has not constitute a standardized, serialized product platform because of late start and backward industrial base. There are disparities in system reliability and stability, so that it is difficult to satisfy the urgent need of railway equipment modernization and railway leap-forward development. Therefore, it is important particularly to research and develop high-power AC drive electric locomotive, especially traction converter.In this paper, traction converter main circuit, key electrical component and control strategy are introduced firstly.Secondly, combined with theoretical calculations and engineering practice, the key components of traction converter have been analyzed. The parameter formula and selection principle of IGBT, sustain capacitor, resonant inductor, resonant capacitor and power resistor have been given.Followed by, power loss and junction temperature of power device have been analyzed, the simulation result being given. By comparing different cooling methods, it is obtained that closed-loop water cooling system is the most appropriate choice for high-power locomotive traction converter. It has been described in detail, including the cooling system structure and working principle of traction converter, the characteristics of integrated cooling tower, the design principles of radiator and the choice of cooling medium.Finally, structure design, thermal design and electrical performance of traction converter are verified by simulation and experiment. The results show that the main technical bench-mark fully meets the requirement and the development is successful. From practical engineering of traction converter, high-power locomotive traction converter with completely independent intellectual property has been designed through prototype testing and simulation, offering reference for other converter in future.