考虑反向关断特性的晶闸管数字建模方法

Digital Modeling Method of Thyristor Considering Reverse Turn-off Characteristics

常用电磁暂态仿真软件提供的晶闸管模型忽略了晶闸管的反向关断特性,导致晶闸管换流器的换相失败仿真不精准。为提高对晶闸管阀的仿真准确性,建立了考虑过零点电流变化率、正向电流峰值和结温作用下晶闸管关断特征参数反向恢复电流峰值、反向恢复电荷和关断时间的影响关系;提出了相关影响因素在器件建模中的表征方法,建立包括晶闸管反向阻断恢复过程和正向阻断恢复过程在内的晶闸管自定义数字仿真模型,并构建了考虑器件关断特性的换流器精细化电磁暂态模型。晶闸管模型仿真结果同实际测试值对比,反向恢复电流峰值的仿真误差不超过5%,关断时间的仿真误差小于4%,提出的数字仿真模型能较精确反映晶闸管的关断过程;换流器仿真模型能更准确地反映高压直流系统换相失败特征。

The thyristor model provided by common electromagnetic transient simulation software ignores the reverse turn-off characteristics of thyristor,resulting in inaccurate simulation of commutation failure of the thyristor converter.In order to improve the simulation accuracy of thyristor valve,we established a effect relationship of zero-crossing current change rate,positive current peak and junction temperature on the reverse recovery current peak,reverse recovery charge and turn-off time of thyristor turn-off characteristic parameters.Meanwhile,we proposed a characterization method of re-lated influencing factors in device modeling,and established a custom digital simulation model of thyristor including reverse blocking recovery process and forward blocking recovery process.Moerover,we constructed a refined electro-magnetic transient model of the converter considering the turn-off characteristics of the device.The comparison between the simulation results and the actual test values shows that the simulation error of the reverse recovery current peak is less than 5%,and the simulation error of the turn-off time is less than 4%.The proposed digital simulation model can accu-rately reflect the turn-off process of the thyristor.The converter simulation model can more accurately reflect the commutation failure characteristics of HVDC system.