Analysis and Experimental Verification of Reducing Intra-winding Capacitance in a Copper Foil Transformer

Ramachandran, Rakesh; Nymand, Morten; Nielsen, Jesper

doi:10.1109/apec39645.2020.9124388

Cited by 4 publications

(7 citation statements)

References 9 publications

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“…Similarly, the equivalent top-surface to core capacitance in Case 2 and Case 3 are calculated as (17) and (18), respectively. d2 0 2 tc_case2 1 1 1 2 2 2 1 1 winding winding tc_case2 eq_tc_case2 2…”

Section: C22 Dynamical Capacitance Between the Top-surface Of Windimentioning

confidence: 99%

Parasitic Capacitance in Copper-Foiled Medium-Voltage Filter Inductors

Zhao¹,

Huang²,

Dalal³

et al. 2020

Preprint

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This paper characterizes three parasitic capacitances in copper-foiled medium-voltage inductors. It is found that the conventional modeling method overlooks the effect of the fringe field, which leads to inaccurate modeling of parasitic capacitances in copper-foiled inductors. To address this problem, the parasitic capacitances contributed by the fringe field is identified first, and a physics-based analytical modeling method for the parasitic capacitances contributed by the fringe field is proposed, which avoids using any empirical equations. The total parasitic capacitances are then derived for three different cases with three different core potentials, from which a three-terminal equivalent circuit is derived, and thus, the parasitic capacitances in copper-foiled inductors are explicitly identified. The calculated results show a close agreement with the measured capacitance by using an impedance analyzer.

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Section: C22 Dynamical Capacitance Between the Top-surface Of Windimentioning

confidence: 99%

Parasitic Capacitance in Copper-Foiled Medium-Voltage Filter Inductors

Zhao¹,

Huang²,

Dalal³

et al. 2020

Preprint

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“…The windings of inductors are commonly constructed with round cables for a low cost. Yet, in high-frequency applications, both the copper foil and the litz wire are commonly used for a lower ac-resistance [17], and the copperfoil is more popular in high-voltage and high-power applications [17][18][19][20], due to its higher power density and more flexibility than round cables and Litz wires in the manufacturing process. However, the intra-winding capacitance of the copper-foiled inductors and transformers is large due to the extensive interleaving of the windings [17], which is not desirable in applications with high dv/dt operations.…”

Section: Introductionmentioning

confidence: 99%

“…Yet, in high-frequency applications, both the copper foil and the litz wire are commonly used for a lower ac-resistance [17], and the copperfoil is more popular in high-voltage and high-power applications [17][18][19][20], due to its higher power density and more flexibility than round cables and Litz wires in the manufacturing process. However, the intra-winding capacitance of the copper-foiled inductors and transformers is large due to the extensive interleaving of the windings [17], which is not desirable in applications with high dv/dt operations. Therefore, it is important to characterize and reduce the parasitic capacitances in copper-foiled filter inductors, especially when they are used in the converters based on WBG devices.…”

Section: Introductionmentioning

confidence: 99%

Parasitic Capacitance Modeling of Copper-Foiled Medium-Voltage Filter Inductors Considering Fringe Electrical Field

Zhao

Huang

Dalal

et al. 2021

IEEE Trans. Power Electron.

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This paper characterizes three parasitic capacitances in copper-foiled medium-voltage inductors. It is found that the conventional modeling method overlooks the effect of the fringe field, which leads to inaccurate modeling of parasitic capacitances in copper-foiled inductors. To address this problem, the parasitic capacitances contributed by the fringe electrical field is identified first, and a physics-based analytical modeling method for the parasitic capacitances contributed by the fringe electrical field is proposed, which avoids using any empirical equations. The total parasitic capacitances are then derived for three different cases with three different core potentials, from which a three-terminal equivalent circuit is derived, and thus, the parasitic capacitances in copper-foiled inductors are explicitly identified. The calculated results show a close agreement with the measured capacitance by using an impedance analyzer. Two recommendations for reducing the parasitic capacitances in copper-foiled inductors are given in this paper.

show abstract

“…Yet, in high-frequency applications, both the copper foil and the litz wire are commonly used for a lower ac-resistance [17], and the copper-foil is more popular in the high-voltage and high-power applications [17][18][19][20], due to its higher power density and more flexibility than round cables and Litz wires in the manufacturing process. However, the intra-winding capacitance of the copper-foiled inductors and transformers is large, due to the extensive interleaving of the windings [17], which is not desirable in applications with a high dv/dt operations. Therefore, it is important to model the parasitic capacitances in copper-foiled inductors when they are used with MV SiC MOSFETs.…”

Section: Introductionmentioning

confidence: 99%

“…The dynamical capacitance can be calculated by the static capacitance and dynamical voltage potential distribution. In [17], the parasitic capacitance of a copper-foil-based transformer between the primary side and secondary side is calculated by using the formula of parallel plate capacitance, which is, however, merely a static capacitance, and thus fails to capture the dynamical capacitance in practice [14], [21], [22]. An air-coiled inductor wounded by copper foils is modeled in [20], where the first resonant frequency caused by the intra-winding capacitance is identified, yet the modeling of parasitic capacitance is not addressed.…”

Section: Introductionmentioning

confidence: 99%