Research On Design Method And Heat Transfer Ance Of Liquid-cooling Equipment Of High Power Locomotive Traction Converter

Abstract:Traction converter is an important part of high power AC-drive locomotive electrical system. If the temperature overincreases during the operation of locomotive, the traction converter will be stopped and the locomotive running safely and stability cannot be guaranteed. With the development of locomotive forward to high power, the cooling design has become an important and key research field in the course of high power locomotive traction converter design. However, research on the cooling of high power locomotive traction converter still has some problems to solve:power loss determination method of IGBT modules in different operational states is too complicated, design method of cooling equipment is far from perfection,test method is not applicable to cooling equipment with IGBT modules and so on,which limit the design and application of high performance cooling equipmentIn connection with current research situation, based on localization project of liquid-cooling equipment with IGBT modules used in traction converter of9600kW high power locomotive imported by Central South Rail Company (project number:KKX-WLG-00-002), the paper does the research on design method and heat transfer performance of liquid-cooling equipment of high power locomotive traction converter and its application as following:Firstly, based on the analysis of the principle of locomotive traction converter and working performance of IGBT modules, power loss determination method which bases on device characteristic parameters and curve of IGBT module under conducting and rapid switching state is derived and established. The power losses of IGBT modules used in9600kW high power locomotive traction converter are calculated adopting the method mentioned above and experiments are performed to testify the results. The advantage of this method is compared and analyzed.Secondly, adopting relative theory of heat transfer and hydromechanics, research on the design of liquid-cooling equipment used in high power locomotive traction converter is done. The cooling scheme of traction converter is given, where the design requirements of liquid-cooling equipment are derived from; external structure design method of liquid-cooling equipment is established. Research on thermal resistance is done, including the analysis of heat flow path, the mechanism and key influence factors of convective heat transfer, the thermal resistance determination method of liquid-cooling equipment based on internal flow path parameters is set up. By researching on flow state of cooling medium in liquid-cooling equipment, the flow resistance determination method of liquid-cooling equipment based on internal flow path parameters is set up. The three parts of research mentioned above constructs a set of design method of liquid-cooling equipment used in high power locomotive traction converter.Then, research on numerical modeling and solving method of liquid-cooling equipment used in high power locomotive traction converter is done. Firstly, the method to establish three-dementional calculation area adopting geometric modeling techniques and mesh generation technology of calculation area are given. Then, k-∈model is selected to simulate the turbulent motion of liquid-cooling equipment, three-dimentional flow and heat transfer control equation for viscous fluid is given. Finally, the method and process to solve control equation using finite volume method is set up and the approach to set boundary conditions and physical property parameters during the course of simulation of liquid-cooling equipment is given.Then, the liquid-cooling equipment used in9600kW locomotive traction converter is designed adopting the power loss determination method and design method mentioned above. Using the numerical modeling and solving method abtained, the heat transfer and flow performance of liquid-cooling equipment used in traction converter of9600kW high power locomotive designed above is simulated. The performance index of designed liquid-cooing equipment is gained.At the same time, the effect rules of inlet flow rate, cooling medium and pin-fin structure to the performance of liquid-cooling equipment is found. Finally, the performance test method is researched and developed. A set of more effective and intuitive test method and devices are self-designed. The heat transfer and flow performance of liquid-cooling equipment used in traction converter of9600kW high power locomotive designed are tested and analyzed. The effect rules of inlet flow rate, cooling medium and dissipation power to the performance of liquid-cooled plate is tested and analyzed. The results proved that design theory and simulation model of liquid-cooling equipment used in locomotive traction converter are correct.The researches above forms a design method for liquid-cooling equipment of high power locomotive traction converter and perfect the key technology research of cooling of traction converter,which supply a theory foundation for further development of traction converter cooling design and cooling technology.