基于双阻抗校准和麦夸尔特法的阻抗提取

Impedance Extraction Method Based on Dual Impedance Calibration and Levenberg-Marquardt’s Algorithm

为了有效降低电子设备产生的传导电磁干扰噪声,需要设计合适的电磁干扰滤波器,而噪声抑制效果与噪声源阻抗的精度有关。插入损耗法和电流探头法等传统方法虽能初步得到噪声源阻抗,但测试电路耦合电容和测试过程中存在的近似及约束条件会严重影响测试结果,亦无法得到噪声源阻抗的幅值和相位。针对上述问题,该文提出了基于双阻抗校准和麦夸尔特法的噪声源阻抗提取方法,分别利用2个电流探头和2个标准阻抗获取被测噪声源阻抗的幅值和相位,再利用麦夸尔特算法提取全频段(9kHz^30MHz)噪声源阻抗的频率特性,并确定其电阻、电容和电感参数。实验结果表明,采用文中方法能够较大提高噪声源阻抗的提取精度,从而为EMI滤波器的设计提供理论依据。

In order to suppress the conducted electromagnetic interference（EMI） noise generated by electronic devices,EMI filter should be designed well,while noise mitigation performance was decided by the accuracy of noise source impedance（NSI）.The NSI can be obtained roughly by employing the traditional methods including insertion method and current probe method.However,the results were influenced with the coupling capacitor,assumption and limitation in measurement process.Moreover,the amplitude and phase of the NSI can’t be received.A novel NSI approach was presented to solve the above problems based on dual impedance calibration and Levenberg-Marquardt’s algorithm.The amplitude and phase of the NSI was acquired by using dual current probes and dual standard impedances.Then the full-band（9 kHz^30 MHz） spectrum characteristics of the NSI and its resistance,capacitor and inductance parameter can be obtained by utilizing the Levenberg-Marquardt’s algorithm.Experimental results show the accuracy for extracting NSI was improving by the presented method,thus providing the theoretical basis for EMI filter design.