Nowadays accurate characterization of the magnetic component losses becomes increasingly important in the design stage of power converters. As the main challenge in characterizing a magnetic component, the core loss is commonly measured through the two winding B-H loop measurement method that is susceptible to the phase discrepancy error, especially for low-permeability, low-loss cores. This paper, therefore, proposes a new offline method to compensate the phase discrepancy error in high-frequency core loss measurement under rectangular voltage excitation. In the post-processing of measured waveforms, the phase discrepancy is compensated by shifting the measured current horizontally to align with a reference phase angle, which is found from an offline impedance sweep on the component-under-test and FFT analysis. As a result, the testing voltage and current waveforms can be measured without considering deskew at the time of measuring. Additionally, this method is more accurate than calibration methods considering a fixed frequency response (e.g., a deskew fixture), because it considers the frequency response across the whole spectrum. The proposed approach can be well applied for typical PWM converters with switching frequencies up to hundreds of kilohertz, for which the effective voltage harmonics extend to a few megahertz range that can be well evaluated with an impedance analyzer. The presented method is experimentally verified against the existing partial cancellation method which is immune to phase discrepancy error.

中文翻译：

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矩形电压测量铁损相位差离线补偿新方法


如今，在功率转换器的设计阶段，磁性元件损耗的准确表征变得越来越重要。作为表征磁性元件的主要挑战，磁芯损耗通常通过两绕组 BH 环测量方法来测量，该方法容易受到相位误差误差的影响，特别是对于低磁导率、低损耗磁芯。因此，本文提出了一种新的离线方法来补偿矩形电压励磁下高频铁损测量中的相位差误差。在测量波形的后处理中，通过水平移动测量电流以与参考相位角对齐来补偿相位差，参考相位角是通过对被测器件的离线阻抗扫描和 FFT 分析找到的。结果，可以在测量时不考虑时滞校正的情况下测量测试电压和电流波形。此外，该方法比考虑固定频率响应（例如，相差校正夹具）的校准方法更准确，因为它考虑了整个频谱的频率响应。所提出的方法可以很好地应用于开关频率高达数百千赫兹的典型 PWM 转换器，其中有效电压谐波扩展到几兆赫兹范围，可以使用阻抗分析仪很好地评估。该方法针对现有的不受相位差误差影响的部分抵消方法进行了实验验证。