基于晶闸管开关特性的SVC传导干扰仿真模型

Simulation of the Conducted Interference Derived from SVC Based on the Switching Characteristics of Thyristors

为分析和预测由静态无功补偿器(SVC)产生的高频传导电磁干扰,基于晶闸管的动态开关特性,给出了SVC传导干扰仿真的建模方法,它以非线性时变电阻作为晶闸管宏模型的内核,建立含有晶闸管控制电抗器(TCR)支路与晶闸管开关电容器(TSC)支路的SVC仿真模型。模型中晶闸管的动态开关特性由非线性时变电阻阻值的变化来表示。此外,为提高传导干扰预测水平,在仿真模型中还加入了测量传感器的幅频特性校正算法。通过增加一阶导数信息,该校正算法改进了复向量拟合法,以进一步提高拟合精度。SVC传导干扰的仿真结果与现场实测数据相比具有相似性,表明晶闸管的动态开关特性是导致高频传导干扰的主要原因。

Based on the dynamic switching characteristics of the thyristors, a simulation methodology is established to investigate the high-frequency conducted interference derived from SVC （Static Var Compensator） devices. With a nonlinear time-varying resistance as the kernel of the high-frequency macro model for thyristors, a concrete simulation model of SVC including a TSC （Thyristor Switched Capacitor） element and a TCR （Thyristor Controlled Reactor） element is further proposed. In the simulation model, the variation of nonlinear time-varying resistance value is used to represent the dynamic switching characteristics of the thyristors. In addition, a digital correction algorithm for frequency domain compensation of the measuring probes is also incorporated as to ameliorate the accuracy of EMI （Electromagnetic Interference） prediction. The digital correction algorithms is an improved vector fitting methodology which is realized by introduction of the first-order derivative information to the coefficient matrix based on the previously available vector fitting methodology. The conducted interference by simulations is correlated well with that from the on-site measurements, which indicates that the dynamic switching characteristics of the thyristors are the main causes of the high-frequency conducted emissions.