An accurate and fast transient calorimetric ferrite core-loss measurement method is proposed in this article. In contrast to electrical measurements, the accuracy of the calorimetric approach is largely independent of the magnetic excitation and operating frequency. However, accurate values of the thermal capacitance and the temperature of the core under test (CUT) are required. Accurate measurement of the specific heat capacity of the core material can be achieved with a differential scanning calorimeter (DSC) or by using the CUT as a dc electric conductor and measuring its thermal response for known Joule heating. Accurate temperature measurements can be realized with NTC temperature sensors. A thorough uncertainty analysis of the presented method is conducted by identifying the impact of each source of uncertainty in the course of a sensitivity analysis. For the considered reference case (R 22.1/13.7/7.9 toroidal core with N49 ferrite material by EPCOS-TDK - 500 kHz/100 mT), the method achieves a total uncertainty with a worst-case value of less than 12% or, in case of a more realistic approach considering a Gaussian distribution of each source of uncertainty, a mean value of −4.3% with a 95% confidence interval of $\mathbf {\pm }$3.2%. The results are verified by means of finite element method (FEM) simulations and experiments. Furthermore, a step-by-step description of the workflow for preparing and conducting the experiments is provided. The proposed method is tested experimentally and compared to a state-of-the-art electrical loss measurement method for MnZn N87 and N49 ferrite cores of EPCOS-TDK. In addition, it is used to measure the loss-map of the NiZn ferrite material 67 from Fair-Rite for very high frequencies up to 50 MHz, which enables the computation of the material's Steinmetz parameters.

中文翻译：

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高达 50MHz 的铁氧体磁芯损耗的瞬态量热测量

本文提出了一种准确快速的瞬态量热铁氧体磁芯损耗测量方法。与电测量相反，量热法的精度在很大程度上与磁激励和工作频率无关。但是，需要准确的热容值和被测磁芯 (CUT) 的温度。可以使用差示扫描量热计 (DSC) 或通过使用 CUT 作为直流电导体并测量其对已知焦耳热的热响应来准确测量核心材料的比热容。NTC温度传感器可以实现准确的温度测量。通过在敏感性分析过程中确定每个不确定性来源的影响，对所提出的方法进行彻底的不确定性分析。对于所考虑的参考情况（R 22.1/13.7/7.9 环形磁芯，EPCOS-TDK 的 N49 铁氧体材料 - 500 kHz/100 mT），该方法实现了总不确定度，最坏情况值小于 12%，或者，在考虑到每个不确定性来源的高斯分布的更现实方法的情况，平均值为 -4.3%，95% 置信区间为 $\mathbf {\pm }$3.2%。结果通过有限元方法 (FEM) 模拟和实验得到验证。此外，还提供了准备和进行实验的工作流程的分步说明。所提出的方法经过实验测试，并与 EPCOS-TDK 的 MnZn N87 和 N49 铁氧体磁芯的最新电损耗测量方法进行了比较。此外，它还用于测量来自 Fair-Rite 的 NiZn 铁氧体材料 67 在高达 50 MHz 的极高频率下的损耗图，从而能够计算材料的 Steinmetz 参数。