基于二步法的多芯电缆非侵入式电流测量校正方法

Calibration method for the noninvasive current measurement of multicore cables based on two-step estimation

为了解决多芯电缆的非侵入式电流测量由于被测对象信号微弱、系统灵敏度高、易受环境因素干扰,造成测量误差较大的问题,采用磁阻传感器的非侵入式电流测量系统为研究对象,在分析系统测量方法及硬铁、软铁和比例因子等误差构成的基础上,提出一种基于二步法的误差校正方法,该方法通过对传感器输出信号进行非线性变换,构造了与误差相对应的矩阵方程,并在对方程求解后进行非线性回归计算,从而实现对多芯电缆的电流测量值的动态误差修正.实验结果表明,该方法可以同时校正非侵入式电流测量系统的线性误差与部分非线性误差.

The noninvasive measurement of multicore cables using space magnetic field analysis has characteristics of weak signal intensity,high sensitivity,and vulnerability to environmental or elemental interference. To calibrate the hard iron bias,soft iron bias,and scale factor of magnetoresistance sensors based on noninvasive measurements for multicore cables,a two-step estimation-based calibration method was proposed. This method establishes the error-related linear matrix equations through the nonlinear transformation of the sensor output signal and undertakes nonlinear regression calculation after solving the equations,thus implementing dynamic error correction for the measurement of multicore cable current. Results show that this method can simultaneously calibrate linear and partial nonlinear errors of noninvasive current measurement devices for multicore cables.