用于防雷器带电试验组合波发生器电路参数的理论计算

Theoretical Calculation Applied in Circuit Parameters of Combination Wave Generator for SPD Charging Test

组合波信号发生器(CWG)主要用于浪涌保护器或电子设备电磁兼容试验,要求在虚拟阻抗Z为2Ω的情况下,输出1.2/50μs开路电压波或8/20μs短路电流波。基于电路微分方程的方法对CWG等效电路进行数学计算,导出相应的数学关系,给出一套计算图表。对电路参数计算结果进行电路仿真,并将计算结果应用于实际CWG电路设计。同CWG标准参数要求比对,仿真结果最大偏差小于6%;实际设计的CWG参数最大偏差小于8%。结果表明,针对CWG电路参数的计算采用的方法是正确的,计算结果可以应用于CWG设计中电路参数的选取。

The combination wave generator is used mainly for surge protective devices or electromagnetic compatibility test. The output voltage wave, the output current wave and the output equivalent impedance （it is named virtual impedance Z） are important characteristics of CWG. According to IEC standard, the output waveforms, which include the 1.2/50 μS open voltage wave or the 8/20 μS short curTent wave, should be generated by CWG under the condition of Z=2 Ω. The paper aims to decide tire parameters of CWG circuit through the circuit calculation. Firstly, from the CWG equivalent circuit differential equation, a set of charts for selecting circuit parameters are elicited, and according to these charts, the circuit parameters of CWG are chosen. Secondly, the designed circuit is simulated and developed, the tested results prove that the error is less than 6% and 8% comparing the simulated waves and the tested waves with the IEC standard respectively. It is verified that the method of calculation is correct.