A simple mathematical expression for nonlinear resistive properties of metal oxide varistor (MOV) elements is proposed for electromagnetic and surge simulations using the finite-difference time-domain (FDTD) method. The nonlinear resistive properties of MOV elements are obtained experimentally as the voltage versus current (V-I) characteristics. The V-I characteristics are converted to the resistivity versus electric field (ρ-E) characteristics. The ρ-E characteristics are approximated by the simple mathematical expression with three adjustable constants, the values of which can be easily determined with the least square method. The proposed simple ρ-E expression is of great use in FDTD simulations since it can approximate measured ρ-E characteristics reasonably well and requires no iterative computations.

中文翻译：

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用于 FDTD 仿真的金属氧化物压敏电阻元件非线性电阻特性的近似数学表达式


提出了一种金属氧化物压敏电阻 (MOV) 元件非线性电阻特性的简单数学表达式，用于使用时域有限差分 (FDTD) 方法进行电磁和浪涌仿真。 MOV 元件的非线性电阻特性是通过实验获得的电压与电流 (VI) 特性。 VI 特性转换为电阻率与电场 (ρ-E) 特性。 ρ-E 特性通过具有三个可调常数的简单数学表达式来近似，可以使用最小二乘法轻松确定其值。所提出的简单 ρ-E 表达式在 FDTD 模拟中非常有用，因为它可以很好地近似测量的 ρ-E 特性并且不需要迭代计算。