Research And Implementation Of Key Technology Of High Power Thyristor Current Equalization Test Bench

With the rapid development of power electronic devices,semiconductor switching devices(thyristors,GTOs,IGBTs,etc.)are more and more widely used in industrial production,and industrial production requirements for devices are also increasing,especially in some industries,such as chemical industry.Metallurgy,railway transportation,etc.,the current and voltage required for equipment work are large,and individual semiconductor switching devices often cannot meet the needs.It is often necessary to use these switching devices in series and in parallel.A large number of semiconductor switching devices are used in the rectifier cabinets of railway locomotives.Due to the high voltage and high current output of the locomotive rectifier cabinets,the rectification semiconductor switching devices generally use series-parallel technology,due to the difference in volt-ampere characteristics of each switching device and the opening.Inconsistent on-off time will result in uneven current or voltage distribution in the rectifier circuit of the switching device.This unevenness will cause a certain degree of damage,which will cause direct damage to the switching device.Therefore,it must be used in series-parallel application of semiconductor switching devices.The voltage equalization current sharing test is used to ensure the uniformity of the voltage or current distribution of these devices.In this paper,the high-power thyristor current sharing pressure test is taken as the research object,and the key technologies in the pressure equalization current flow test are studied,including the test high current load technology in the current sharing test and the high test voltage generation in the voltage equalization test.Technology;also has the trigger technology,automatic wiring control technology and automatic test technology for the high-power thyristor in the design of the equalizing flow test bench of the main rectifier cabinet of the Lushan series of electric locomotives in China.The research content of this paper is divided into the following aspects:(1)The single-phase and three-phase rectifier circuits are analyzed,and the calculation of the current and withstand voltage of the rectifier switching device is given.The characteristics of the typical rectifier device diode and thyristor are introduced,which provides a theoretical basis for the application of voltage equalization and current sharing.(2)The key technology in the equalization and pressure equalization test of highpower switchgear is studied.The design of the equalizing current equalization test bench of the main rectifier cabinet of Lushan series electric locomotive is studied.The test power supply,load object,thyristor triggering,etc.Test process control automation and test test automation system.(3)The design realizes the hardware circuit of the equalizing current test bench of the main rectifier cabinet of the Shaoshan series electric locomotive,including the test power main circuit,the test automatic control circuit,the thyristor trigger circuit and the test data acquisition circuit.(4)The control program of the pressure equalizing current sharing test bench is designed,including the upper computer monitoring software system for the test process control and the lower device thyristor pulse trigger system program.Finally,the test bench designed and manufactured by the test bench for the SS6 B and SS3 G electric locomotive rectifier cabinets are subjected to current sharing test and voltage equalization test.The operation results show that the research technology can be applied to the design of the rectifier equalization flow test bench.