| 1. |
- Beccuti, A. G., et al.
(författare)
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Hybrid control techniques for switched-mode DC-DC converters part II : The step-up topology
- 2007
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Ingår i: 2007 American Control Conference, Vols 1-13. - 1424409888 - 9781424409884 ; , s. 5464-5471
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Konferensbidrag (refereegranskat)abstract
- Several recent techniques from hybrid and optimal control are evaluated on a power electronics benchmark problem. The benchmark involves a number of practically interesting operating scenarios for a fixed-frequency step-up dc-dc converter. The specifications are defined such that good performance can only be obtained if the switched and nonlinear nature of the problem is respected during the design phase.
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| 2. |
- Kapran, Olena M., et al.
(författare)
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In situ transport characterization of magnetic states in Nb/Co superconductor/ferromagnet heterostructures
- 2021
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Ingår i: Beilstein Journal of Nanotechnology. - : Beilstein Institut. - 2190-4286. ; 12, s. 913-923
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Tidskriftsartikel (refereegranskat)abstract
- Employment of the non-trivial proximity effect in superconductor/ferromagnet (S/F) heterostructures for the creation of novel superconducting devices requires accurate control of magnetic states in complex thin-film multilayers. In this work, we study experimentally in-plane transport properties of microstructured Nb/Co multilayers. We apply various transport characterization techniques, including magnetoresistance, Hall effect, and the first-order-reversal-curves (FORC) analysis. We demonstrate how FORC can be used for detailed in situ characterization of magnetic states. It reveals that upon reduction of the external field, the magnetization in ferromagnetic layers first rotates in a coherent scissor-like manner, then switches abruptly into the antiparallel state and after that splits into the polydomain state, which gradually turns into the opposite parallel state. The polydomain state is manifested by a profound enhancement of resistance caused by a flux-flow phenomenon, triggered by domain stray fields. The scissor state represents the noncollinear magnetic state in which the unconventional odd-frequency spin-triplet order parameter should appear. The non-hysteretic nature of this state allows for reversible tuning of the magnetic orientation. Thus, we identify the range of parameters and the procedure for in situ control of devices based on S/F heterostructures.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Almér, S., et al.
(författare)
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Application of model predictive control and analysis of switched systems to the direct voltage control of AC-DC converters
- 2015
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Ingår i: 2009 European Control Conference, ECC 2009. - : IEEE. - 9783952417393 ; , s. 3593-3598
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Konferensbidrag (refereegranskat)abstract
- Recent tools for control and analysis of hybrid systems are applied to an AC-DC converter. The topology poses particularly challenging problems since it is unusually complex and the circuit parameters are such that the dynamic coupling between the AC and DC sides cannot be ignored. The paper proposes a model predictive control scheme for direct voltage control which circumvents the bandwidth limitations associated with classical cascade control. The stability and harmonic properties of the resulting closed loop system are investigated using new tools for the analysis of switched systems.
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| 8. |
- Almér, Stefan, et al.
(författare)
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Hybrid control techniques for switched-mode DC-DC converters part I : The step-down topology
- 2007
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Ingår i: 2007 American Control Conference. - : IEEE. - 1424409888 - 9781424409884 ; , s. 5450-5457
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Konferensbidrag (refereegranskat)abstract
- Several recent techniques from hybrid and optimal control are evaluated on a power electronics benchmark problem. The benchmark involves a number of practically interesting operating scenarios for a fixed-frequency synchronous step-down dc-dc converter. The specifications are defined such that good performance only can be obtained if the switched and nonlinear nature of the problem is respected during the design phase.
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| 9. |
- Balluchi, A., et al.
(författare)
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Hybrid control of networked embedded systems
- 2005
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Ingår i: European Journal of Control. - : LAVOISIER. - 0947-3580 .- 1435-5671. ; 11:4-5, s. 478-508
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid systems that involve the interaction of continuous and discrete dynamics have been an active area of research for a number of years. In this paper, we start by briefly surveying the main theoretical control problems that have been treated in the hybrid systems setting and classify them into stabilization, optimal control and language specification problems. We then provide an overview of recent developments in four of the most prominent areas where these hybrid control methods have found application: control of power systems, industrial process control, design of automotive electronics and communication networks.
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| 10. |
- Chioncel, L., et al.
(författare)
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Transmission through correlated CunCoCun heterostructures
- 2015
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 92:5
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Tidskriftsartikel (refereegranskat)abstract
- We propose a method to compute the transmission through correlated heterostructures by combining density functional and many-body dynamical mean field theories. The heart of this combination consists in porting the many-body self-energy from an all electron basis into a pseudopotential localized atomic basis set. Using this combination we study the effects of local electronic interactions and finite temperatures on the transmission across the Cu4CoCu4 metallic heterostructure. It is shown that as the electronic correlations are taken into account via a local but dynamic self-energy, the total transmission at the Fermi level gets reduced (predominantly in the minority-spin channel), whereby the spin polarization of the transmission increases. The latter is due to a more significant d-electron contribution, as compared to the noncorrelated case in which the transport is dominated by s and p electrons.
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