Research On Current Source Converter For Triggering High-voltage Valves

Due to the limited voltage ratings of the commercially available power devices,an option for power switching in the fields such as high-voltage motor soft-startingand large-capacity VAR compensation is to series multiple, lower voltage-ratedpower devices. High-voltage valves such as series thyristor valves and series IGBTvalves are increasingly popular with the development of power electronicstechnology. Unfortunately, mature products in related fields are still far fromenough because of the studies on their triggering technology is still insufficient.Facing the difficulties such as high-voltage insulation, multiple outputs, andsynchronous strong triggering pulse, triggering technology becomes a key problemof high-voltage valves.The current source converter, one of the key technologies of triggeringhigh-voltage valves, is studied in this thesis.Firstly, the background and the meaning of this study are presented. Based onthe study of existing triggering technologies, mainly about the specificcharacteristics of high-voltage valves, and the advantage and disadvantage oftopologies used in triggering high-voltage valves, a buck converter is selected as theconstant current source converter. Then a novel method for controlling the status ofthe current source converter through full-bridge converter is proposed.Secondly, the key parameters are calculated based on the technical indicators.The small-signal model of the constant current source converter is built, thus anopen-loop transfer function can be got, and a compensator can be designed. Afterthat, a simulation model is set up on PSIM simulation platform. The topology,parameters, and dynamic performance are checked and improved through thesimulation.Finally, an experimental prototype converter is built. Experimental results fromthe prototype converter indicate the converter performs well. The goal of multipleoutputs and synchronous, insulated, strong trigger pulse is achieved.