New core loss measurement method for high frequency magnetic materials

Mu, Mingkai; Li, Qiang; Gilham, David; Lee, Fred C.; Ngo, Khai D. T.

doi:10.1109/ecce.2010.5618454

Cited by 52 publications

(32 citation statements)

References 6 publications

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“…K and β are called Steinmetz parameters. K and β have been calculated for several commercial low-permeability rf magnetic materials from 20 MHz to 70 MHz in [22], [24], [28].…”

Section: Inductor Design Procedures and Methodsmentioning

confidence: 99%

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Inductor design methods with low-permeability RF core materials

Han

Perreault

2010

2010 IEEE Energy Conversion Congress and Exposition

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Abstract-This paper presents a design procedure for inductors based on low-permeability magnetic materials, for use in very high frequency (VHF) power conversion. The proposed procedure offers an easy and fast way to compare different magnetic materials based on Steinmetz parameters and quickly select the best among them, to estimate the achievable inductor quality factor and size, and to design the inductor. Approximations used in the proposed methods are discussed. Geometry optimization of magnetic-core inductors is also investigated. The proposed design procedure and methods are verified by experiments. I. BACKGROUNDThere is a growing interest in switched-mode power electronics capable of efficient operation at very high switching frequencies (e.g., 10-100 MHz) [ (which utilize high frequency operation to achieve small size and fast transient response.) These designs utilize magnetic components operating at high frequencies, and often under large flux swings. These magnetic components should have a high quality factor to achieve high efficiency power conversion. Unfortunately, most high-permeability magnetic materials exhibit unacceptably high losses at frequencies above a few megahertz. There are some low-permeability materials (e.g., relative permeabilities in the range of 4-40) that can be used effectively at moderate flux swings at frequencies up to many tens of megahertz [22]-[24]. However, working with such low-permeability materials -and the ungapped core structures they are typically available in -presents somewhat different constraints and challenges than with typical highpermeability low-frequency materials [25]. Because of VHF operation and the low-permeability characteristics of such materials, the operating flux density is limited by core loss rather than saturation, and a gap is not necessary to prevent the core from saturating in many applications. Without a gap, the core loss begins to dominate the total loss and copper loss can be ignored in many cases. The performance of a VHF magnetic-core inductor thus depends heavily on the loss characteristics of the magnetic material. Moreover, there appears to be a lack of good design procedures for a selecting among low-permeability magnetic materials and available core sizes. This paper, which expands upon an earlier conference paper [26], investigates a design procedure for inductors using low-permeability magnetic materials. This method is based on knowledge of the material loss characteristics, such as collected in [22], [24], and is particularly suited for VHF inductor designs. With the methods developed here, different magnetic materials are compared fairly and conveniently, and both the achievable quality factor and size of a magnetic-core inductor can be evaluated before the final design.Section II of the paper introduces the inductor design considerations and questions to be addressed. Section III illustrates the inductor design procedure and methods employed in it. Section IV shows some experimental results to verify the design procedure. Se...

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“…K and β are called Steinmetz parameters. K and β have been calculated for several commercial low-permeability rf magnetic materials from 20 MHz to 70 MHz in [22], [24], [28].…”

Section: Inductor Design Procedures and Methodsmentioning

confidence: 99%

“…3) Design based on knowledge of Steinmetz parameters for materials of interest. Such parameters are often not published or readily available for these materials, but can be obtained using methods such as that of [22], [24], [28]. 4) Design assuming sinusoidal excitation at one frequency.…”

Section: Inductor Design Considerations and Questionsmentioning

confidence: 99%

Inductor design methods with low-permeability RF core materials

Han

Perreault

2010

2010 IEEE Energy Conversion Congress and Exposition

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“…The ac conduction losses are calculated with the squared rms value of the inductor current ac component as (2). The ac resistance is measured by using the method proposed in [19], where the inductor core loss is measured using the resonant method proposed in [20] and separated from the winding loss measurement. The measured ac resistance at the converter switching frequency f sw = 100 kHz is 47.6 mΩ and 1.27 Ω for the charge and discharge intervals, respectively.…”

Section: Loss Distribution Analysismentioning

confidence: 99%

Loss distribution analysis of a three-port converter for low-power stand-alone light-to-light systems

Mira¹,

Knott²,

Andersen³

2016

2016 18th European Conference on Power Electronics and Applications (EPE'16 ECCE Europe)

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In locations far from the equator achieving high conversion efficiency in low-power solar systems is challenging due to low solar irradiance levels. This paper presents a high efficiency three-port converter (TPC) for light-to-light (LtL) applications where no direct solar conversion is required. The separation of the power flows allows to replace the conventional solution of two cascaded converters into a single structure with shared components. A loss distribution analysis of the proposed structure is performed, which shows very good match with the experimental results. A prototype of the TPC demonstrates high efficiency in both power flow paths. At low irradiation level, the photovoltaic to battery stage shows a peak efficiency of 99.1 % at at 1.5 W output power and the LED driver stage presents a peak efficiency of 97.3 % at 3 W output power.

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“…A detailed design methodology for a magnetic component must address the following. 1) Select an appropriate core, which satisfies both electromagnetic conditions and core window area restrictions [1]- [7], [29]. 2) Choose a sufficient air-gap length to avoid core saturation and minimize core power loss [8]- [12] 3) Provide an optimized winding geometry and winding arrangement [13]- [15].…”

mentioning

confidence: 99%

“…An expression to estimate the minimum air gap length required to avoid the two restrictions is provided in Sections III-B and -C. The core losses in ac choke inductors are significantly higher than that in dc choke inductors. An attractive method for core loss measurement was proposed in [29]. As air gap is introduced, the ac flux density in the core decreases by a large factor, thereby reducing the core power loss [9], [10].…”

mentioning

confidence: 99%

Analysis and Design of Choke Inductors for Switched-Mode Power Inverters

Saini

Ayachit

Reatti

et al. 2018

IEEE Trans. Ind. Electron.

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Abstract-This paper presents the design, analytical estimation of power losses, and experimental measurement of choke inductors for switched-mode power inverters. The described approach is applicable to a wide variety of circuits such as Class-E inverters and converters. The expressions required to design the magnetic core in the choke inductor using the area-product ( A p ) method are given. The equations for the dc resistance, ac resistance at high frequencies, and dc and ac power losses are provided for the solid round winding wire. To validate the presented approach, an example class-E zero-voltage switching power inverter with practical specifications is considered. A core with air gap is selected to avoid core saturation in the choke inductor, which conducts dc current and a small ac current. The gapped core power loss density and power loss are estimated using Steinmetz empirical equation. It is shown that the winding power loss due to the dc current is dominant for the given design. A comparison between the area-product A p method and the preexisting core geometry coefficient K g method is presented. The measured magnitude of the inductor impedance has shown that the designed choke is useful up to ten times the switching frequency.

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New core loss measurement method for high frequency magnetic materials

Cited by 52 publications

References 6 publications

Inductor design methods with low-permeability RF core materials

Inductor design methods with low-permeability RF core materials

Loss distribution analysis of a three-port converter for low-power stand-alone light-to-light systems

Analysis and Design of Choke Inductors for Switched-Mode Power Inverters

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