考虑分布参数的光伏阵列测试仪建模及分析

Modeling and analysis of photovoltaic tester which considering influence of distribution parameters

光伏阵列Ⅰ-Ⅴ测试仪在现场测试时,线缆分布参数对测量过程存在干扰,为了估算分布参数对Ⅰ-Ⅴ测试仪现场测试的影响,研究和建立了考虑分布参数的动态电容充电法改进模型。从动态电容充电法公式推导出发,运用基尔霍夫定律,推导出电容电流和电容电压的关系表达式,确认了线缆电感是Ⅰ-Ⅴ测试的主要影响因素,并通过Matlab软件对其进行仿真研究,定量分析了线缆电感对动态电容充电法的影响。给出了一种利用Ⅰ-Ⅴ测试仪计算线缆电感的方法并通过仿真及实验进行验证,为Ⅰ-Ⅴ测试仪优化提供了计算依据。

When the field test of the photovoltaic array Ⅰ-Ⅴ tester is carried out,the cable distribution parameter has interference to the measurement.In order to estimate the influence of distribution parameters on the field test of Ⅰ-Ⅴtester,an improved model of dynamic capacitive charging method considering distribution parameters was established.Based on the formula of dynamic capacitor charging method,Kirchhoff laws are applied to derive the relationship between the capacitance capacitive current and capacitive voltage.It is confirmed that the inductance of cable is the main influence factor of Ⅰ-Ⅴ test.At the same time,the influence of cable inductance on dynamic capacitor charging method is quantitatively analyzed by Matlab.Finally,a method to calculate the inductance of cable by using Ⅰ-Ⅴ tester is presented.And the method is verified by simulation and experiment.It provides the calculation basis for the optimization of Ⅰ-Ⅴ tester.