Improved Partial Cancellation Method for High Frequency Core Loss Measurement

Zhu, Feiyang; Li, Qiang; Lee, Fred C.

doi:10.1109/apec.2019.8722221

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…On one hand, since the proposed method using the same core type and the number of windings of the IUT for the RT, it is relatively easy to fulfil a zero phase angle, and easy to match an inductance of 10 ∼ 1000 μH that is typical in power converters with a switching frequency of less than a few hundreds of kilohertz [37]. On the other hand, the other inductive reactive voltage cancellation methods for core loss measurement cannot match the IUT magnetizing inductance value as accurate as the proposed method, because they utilize air-cored inductors with a large number of windings to reach the matching inductance, which can lead to significant parasitic components and subsequently significant error of measurement [22], [26]- [27], [34]- [36].…”

Section: Sensitivity Analysis a Impact Of Rt Mismatchmentioning

confidence: 93%

“…Additionally, this feature enables the proposed approach to accurately test the cases with the high value of the magnetizing inductances, which is not feasible for other inductive voltage cancellation methods such as Mu's and Hou's methods for core loss measurement; because the achievable inductance of the air-core transformer is limited by the parasitic elements, which could adversely affect the waveforms and the accuracy of the system especially at higher frequencies [22], [26]- [27], [34]- [36].…”

Section: Sensitivity Analysis a Impact Of Rt Mismatchmentioning

confidence: 99%

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A Novel In-Situ Measurement Method of High-Frequency Winding Loss in Cored Inductors With Immunity Against Phase Discrepancy Error

Wang

Yuan

2021

IEEE Open J. Ind. Electron. Soc.

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Evaluating the high-frequency winding loss accurately is crucial for the design of modern high-frequency power converters. This paper proposes a novel experimental method to accurately measure the in-situ inductor winding loss, which separates out the winding loss from the core loss through the reactive voltage cancellation concept. The proposed in-situ measurement can account for the complete winding loss including impacts from non-ideal field distributions by testing the inductor with the core attached, e.g., the winding edge effect, bypass flux, fringing flux, and the non-linear dynamic behaviour of the core, which cannot be well modelled with the existing analytical or simulation methods. This method has immunity against the probe phase discrepancy error, since it is designed to measure a pair of voltage and current that are in phase. This approach can be considered as the first attempt of applying the reactive voltage cancellation concept in measuring winding loss, while this concept was originally brought up for core loss and applied for core loss measurement only. By performing a Triple Pulse Test (TPT) procedure, the winding losses under practical large signals with dc-bias and rectangular voltage can be evaluated with the proposed testing circuit. The proposed approach is compared and verified against the conventional methods relying on (1) small-signal impedance measurements and FFT analysis (2) in-situ measurement with the two winding method to exclude the core loss. The presented method provides a foundation for the accurate in-situ evaluation of winding loss covering all the large-signal and non-linear effects.

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Section: Sensitivity Analysis a Impact Of Rt Mismatchmentioning

confidence: 93%

Section: Sensitivity Analysis a Impact Of Rt Mismatchmentioning

confidence: 99%

A Novel In-Situ Measurement Method of High-Frequency Winding Loss in Cored Inductors With Immunity Against Phase Discrepancy Error

Wang

Yuan

2021

IEEE Open J. Ind. Electron. Soc.

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“…As introduced, Hou's method is insensitive to the phase discrepancy and hence its results are considered as the most accurate baseline to verify the proposed approach. Although, Hou's method also has inherent errors such as the errors caused by the parasitic capacitance of the air-core transformer interwinding capacitance, and a voltage probe input capacitance, as discussed in [10][11][12]. It should be highlighted that the tested iron powder inductor has low permeability, while the proposed method still achieved small differences with respect to Hou's method.…”

Section: Experimental Verificationmentioning

confidence: 96%

“…Table II illustrates the experimental comparison of offline compensated results against uncompensated results for three inductors tested with ± 50V square wave and various frequencies, which are calculated by (11) The results show that for inductor 1 with an iron powder core, the difference is more significant than the other two inductors with ferrite cores. The reason is that the microscopic air gaps distributed in the iron powder core material reduce its core permeability and increase the measurement sensitivity to the skew of probes according to equation (2) and (5).…”

Section: Recalculate Core Loss With the Phase Discrepancy Compensatedmentioning

confidence: 99%

“…As demonstrated in [10], the requirement of the fine-tuned value of the cancellation component is minimized in this method. However, this method is only effective for systems with lower frequencies (e.g., < 5 MHz) compared to Mu's method, due to the considerable reference core loss errors [11], [12]. Furthermore, both Hou's and Mu's inductive cancellation methods are only applicable when the magnetizing inductance of CUT is relatively low (e.g., < a few hundreds of nano-henries).…”

Section: Introductionmentioning

confidence: 99%

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A New Method for Offline Compensation of Phase Discrepancy in Measuring the Core Loss With Rectangular Voltage

Wang

Yuan

2021

IEEE Open J. Ind. Electron. Soc.

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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.

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