Electric Locomotive Optimization Of High-power Ac Drive System Design

After thirty years' research and development, assessment andtechnological updating carried out by the western developed countries. ACdrive system has achieved its rolling stock industry transformation from DCdrive to AC drive. TGV, New Trunk Line and ICE have become importantsigns of railway modernization and national comprehensive strength. ACdrive has become the only selection and develop direction to realize railwayhigh speed and heavy load. Compared with foreign countries, our AC drivesystem has not formed a standard,serial and integrate productplatform, which is restricted by many factors such as late starter,basicindustry technology lag and so on, meanwhile because market procurementof critical component parts are protected by intellectual property, it will alsodo effect. There are also some deficient aspects on assessment to systemstability and reliability so that it will be quite difficult to meet the pressingdemand of realizing technology leapfrogging and modern strategy.Consequently, the optimal design for electric locomotive high power ACdrive system is proved more important.This paper presents a review of main power circuit structure, converterformation and their control methods of AC drive electric locomotive. Withthe help of advanced and reliable simulation technology, we establish theelectric locomotive AC drive system hardware in loop simulation platform,including establishing net-side converter and DC-link system model andestablishing inverter and asynchronous motor tract system model. Weaccomplish three parties real time simulate of main power circuit + control +controlled objects. Besides these, we also form a standard system designplatform and improve the capacity of critical component parts develop,system research and integrity. At the same time, we carry out the optimaldesign for electric locomotive AC drive control strategy by use of thehardware-in-loop simulation platform. As a result, the traditional 6-angularflux trace Direct-Self Control (DSC) is improved to 18-angular flux trace.Simulated and experimental results acquired from the hardware in loopsimulation platform indicate that 18-angular flux trace DSC method improves current waveform and greatly reduces fifth harmonic componentand seventh harmonic component which do great effect on system. We canalso aim at reducing non-periodical components by adjusting the coefficientof angle of bank. This method not only ensures the characteristic of DSCtechnology but also effectively resolves the problem of high harmoniccomponents under the 6 pulse switch mode control method. This effectivelyreduces the interference to electric network and system and improves theperformance of high power AC drive electric locomotive.In the end, the concept and development status of Rapid ControlPrototyping (RCP) technology is introduced in this paper. It realizes theRCP simulation system of electric locomotive AC drive system and makes adiscussion of the optimal design for electric locomotive AC drive systembased on RCP system.