EPE Association: EPE 2019 - LS4a: Passives

EPE 2019 - LS4a: Passives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 01: Devices, Packaging and System Integration > EPE 2019 - LS4a: Passives

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   A novel manufacturing technique for integrating magnetic components windings on power module substrates
By Andrea STRATTA [View]
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Abstract: In this paper a novel manufacturing technique is investigated with the aim of integrating magnetic components (e.g. inductors and transformer) on power module substrates together with the switching devices, to minimize overall dimensions and improve thermal management. The proposed approach consists of bonding copper U-shapes, representative of individual turn of the windings, onto the substrate. This offers an enhanced thermal exchange between the inductors and the cooling system and hence an increase in the current density.

   Analytical calculation of the frequency-dependent litz wire resistance considering the wire connectors
By Daniel BARTH [View]
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Abstract: Eddy-current effects have an impact on the resistance of litz wire. They reduce the utilization of the wire cross section. In a certain parameter range, the dominant influencing factor is the current distribution in the wire connectors. The connector itself does not significantly contribute to the wire resistance but it results in an inhomogeneous current distribution among the strands. We quantify the resistance increase by introducing a connector skin-effect factor and give a mathematical derivation. Taking the twisting of the strands into account requires a probabilistic model of the radial strand position. Resistance measurement results validate the calculation approach. We discuss the assumptions and derive the parameter range where the model is valid.

   Comparison of Analytical Transformer Leakage Inductance Models: Accuracy vs. Computational Effort
By Richard SCHLESINGER [View]
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Abstract: Fast and accurate models of design and operating parameters are crucial for optimisation-based design of power electronic converters. The leakage inductance of transformers is one of these design parameters. This paper compares various analytical 1D and 2D leakage inductance models, and assesses them with respect to a trade-off between accuracy vs. computational effort. The computed leakage inductance per length values are compared to 2D FEM simulation results to determine the model accuracy, whereas the calculation times are extracted as indicator of each model's computational effort. The considered models are applied to six existing transformer geometries and compared to measurements.Roth's model is the most accurate of the considered models, Rogowski's model is the fastest model, and Margueron's model is the most versatile as it takes the magnetic permeability of the core into account.

   High-voltage and high-frequency design of planar transformer with minimum coupling capacitance
By Ole Christian SPRO [View]
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Abstract: This paper investigates the design of a planar transformer operating at 6.78 MHz and with a target maximum isolation voltage of 40 kV using 2D FEM simulations as a tool. In addition, minimal coupling capacitance must be ensured for the target application of auxiliary power supply for medium voltage converters with high EMI immunity. The design space for a transformer with target inductance and coupling capacitance of 1 µH and 10 pF is explored with varying number of winding layers and turns. From the simulation design space, five designs are prototyped for experimental validation. Overall, the prototypes show good coherence with the simulated values with inductance and coupling factors within an error margin of maximum 7\%. Results show that different designs can achieve the same transformer efficiency although with different isolation voltages.

EPE 2019 - LS4a: Passives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 01: Devices, Packaging and System Integration > EPE 2019 - LS4a: Passives
	[return to parent folder]

	A novel manufacturing technique for integrating magnetic components windings on power module substrates By Andrea STRATTA	[View] [Download]
Abstract: In this paper a novel manufacturing technique is investigated with the aim of integrating magnetic components (e.g. inductors and transformer) on power module substrates together with the switching devices, to minimize overall dimensions and improve thermal management. The proposed approach consists of bonding copper U-shapes, representative of individual turn of the windings, onto the substrate. This offers an enhanced thermal exchange between the inductors and the cooling system and hence an increase in the current density.

	Analytical calculation of the frequency-dependent litz wire resistance considering the wire connectors By Daniel BARTH	[View] [Download]
Abstract: Eddy-current effects have an impact on the resistance of litz wire. They reduce the utilization of the wire cross section. In a certain parameter range, the dominant influencing factor is the current distribution in the wire connectors. The connector itself does not significantly contribute to the wire resistance but it results in an inhomogeneous current distribution among the strands. We quantify the resistance increase by introducing a connector skin-effect factor and give a mathematical derivation. Taking the twisting of the strands into account requires a probabilistic model of the radial strand position. Resistance measurement results validate the calculation approach. We discuss the assumptions and derive the parameter range where the model is valid.

	Comparison of Analytical Transformer Leakage Inductance Models: Accuracy vs. Computational Effort By Richard SCHLESINGER	[View] [Download]
Abstract: Fast and accurate models of design and operating parameters are crucial for optimisation-based design of power electronic converters. The leakage inductance of transformers is one of these design parameters. This paper compares various analytical 1D and 2D leakage inductance models, and assesses them with respect to a trade-off between accuracy vs. computational effort. The computed leakage inductance per length values are compared to 2D FEM simulation results to determine the model accuracy, whereas the calculation times are extracted as indicator of each model's computational effort. The considered models are applied to six existing transformer geometries and compared to measurements.Roth's model is the most accurate of the considered models, Rogowski's model is the fastest model, and Margueron's model is the most versatile as it takes the magnetic permeability of the core into account.

	High-voltage and high-frequency design of planar transformer with minimum coupling capacitance By Ole Christian SPRO	[View] [Download]
Abstract: This paper investigates the design of a planar transformer operating at 6.78 MHz and with a target maximum isolation voltage of 40 kV using 2D FEM simulations as a tool. In addition, minimal coupling capacitance must be ensured for the target application of auxiliary power supply for medium voltage converters with high EMI immunity. The design space for a transformer with target inductance and coupling capacitance of 1 µH and 10 pF is explored with varying number of winding layers and turns. From the simulation design space, five designs are prototyped for experimental validation. Overall, the prototypes show good coherence with the simulated values with inductance and coupling factors within an error margin of maximum 7\%. Results show that different designs can achieve the same transformer efficiency although with different isolation voltages.