A Fast Steady-State Loss Model of a Modular Multilevel Converter for Optimization Purposes

A. Papadopoulos,S. Rodrigues,E. Kontos,T. Todorcevic,P. Bauer 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Lesnicar and Marquardt introduced a Modular Multilevel Converter (MMC) topology back in 2003. Although this topology has received a great deal of attention in recent years by both the research community and industry, hitherto no steadystate model has been developed which accurately captured all the relevant power losses while being computationally light. Hence, the aim of this paper is to introduce a fast MMC loss model which captures the key sources of power losses in steady-state operation. The model only requires information which is known a priori, e.g. datasheet information of the components. The proposed model was compared to a loss model developed by Marquardt. Both models presented similar results under the same assumptions. However, the proposed model captures the switching losses more realistically and considers the temperature of operation of the electronics, as well as the losses of the inductors and cooling system in the overall efficiency of the MMC. To validate these new additions, the proposed steady-state model was compared to a dynamic model. Once again the proposed model was able to capture the different sources of power losses. Nonetheless, results demonstrated that the balancing strategy greatly influences the efficiency of the MMC. Therefore, information regarding the envisioned control strategy is necessary to accurately calculate the efficiency curve of the MMC.

A Sectional Matrix Method for IPT Coil Shape Optimization

Venugopal Prasanth,Pavol Bauer,J.A. Ferreira 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In this paper, Neumann’s integral is evaluated for computing self-inductance using a multi-turn sectional matrix method. Analytical equations are derived considering the increase in dimensions of the coil due to an impinging air-gap between the turns. The resulting sectional self-inductance matrix is computed and the concepts of sectional partial self-inductance and sectional partial mutual inductance are introduced. The effects of the various partial inductances are considered as a function of the air-gap, dimensions and turns. Further, the mutual inductance of a pair of coils is considered and the coupling is obtained analytically. The coils considered are to be used for shape optimization of IPT coils. Finally, the results are compared with experimentation. This technique being generic can be applied to a number of different polygonal shapes and can be further simplified by the theory of vector decomposition of current elements. A case study with self-inductance and perimeter as optimization objective is considered.

Pressure-induced relaxor-to-ferroelectric crossover in vinylidene fluoride relaxor terpolymer: a possible explanation to the high performance of the terpolymer nanocomposites

Bauer, Francois,Eyraud, Lucien,Samara, George A.,Seung Tae Choi IEEE 2015 IEEE transactions on dielectrics and electrical in Vol.22 No.3

<P>In this paper, we will present electromechanical behavior of the poly(vinylidene fluoridetrifluoroethylene- 1,1-chlorofluoroethylene) [P(VDF-TrFE-CFE)] terpolymer under hydrostatic pressure. The dielectric data obtained under controlled hydrostatic pressure suggest a reversible pressure-induced crossover from the relaxor state to a ferroelectric state in the terpolymer (PVDF/TrFE/CFE 64.3/27.6/8.1 mol %). It was also observed that the P(VDF-TrFE-CFE) terpolymer quenched in ice water shows ferroelectric-like hysteresis loop. These results have led us to the theoretical analysis of a charged sphere, with which it was estimated that the change of a bipolar state of nanoparticles in a terpolymer matrix to a unipolar state due to a possible ionization of the medium under applied electric field could induce electrostatic pressure high enough to generate relaxor-to-ferroelectric crossover. The hysteresis loop of polymer-modified reduced graphene oxide/poly(vinylidene fluoride-trifluoroethylene-clorotrifluoroethylene) terpolymer nanocomposite was also measured to ensure that the relaxor-to-ferroelectric crossover may take place in the nanocomposite.</P>

The magnetic instability of Yb₂Pd₂(In,Sn) in a non-Fermi liquid environment

Bauer, E,Hilscher, G,Michor, H,Paul, Ch,Aoki, Y,Sato, H,Adroja, D T,Park, J-G,Bonville, P,Godart, C,Sereni, J,Giovannini, M,Saccone, A IOP Pub 2005 Journal of physics, an Institute of Physics journa Vol.17 No.11

<P>Various concentrations of the solid solution Yb<SUB>2</SUB>Pd<SUB>2</SUB>In<SUB>1−<I>x</I></SUB>Sn<SUB><I>x</I></SUB> ranging from <I>x</I> = 0 to 1 with the tetragonal Mo<SUB>2</SUB>FeB<SUB>2</SUB>-type structure were prepared and their physical properties were studied by means of bulk and spectroscopic measurements as a function of temperature, pressure and magnetic fields. Results deduced from these studies indicate a slight variation of the valency of the Yb ions, from <img SRC='http://ej.iop.org/images/0953-8984/17/11/032/cm192308ieqn1.gif' ALIGN='MIDDLE' ALT='\nu \approx 2.9 '/> for both border compounds to &ngr; = 3 at <I>x</I> = 0.6. This variation gives rise to the appearance of long range magnetic order in a narrow concentration region around <I>x</I> = 0.6, while both border compounds remain non-magnetic. The outstanding concentration dependence for the ordered regime may be indicative of two quantum critical points, a novel feature not yet observed in Yb compounds. </P>

Drives and Motion Control Teaching based on Distance Laboratory and Remote Experiments

Markus A. Vogelsberger,Peter Macheiner,Pavol Bauer,Thomas M. Wolbank 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.6

This paper presents the organisation and the technical structure of a remote controlled laboratory in the field of high dynamic drives and motion control. It is part of the PEMCWebLab project with the goal of providing students with practical experience on real systems in the field of power electronics and drives. The whole project is based on clear targets and leading ideas. A set of experiments can be remotely performed on a real system to stepwise identify a two axes positioning system and to design different cascaded control loops. Each single experiment is defined by its goals, the content of how to achieve them, and a verification of the results as well as the achieved learning outcomes. After a short description of the PEMCWebLab project, the structure of the remote control is presented together with the hardware applied. One important point is error handling as real machines and power electronics are applied. Finally, a selection of experiments is presented to show the graphical user interface and the sequence of the laboratory.

Drives and Motion Control Teaching based on Distance Laboratory and Remote Experiments

Vogelsberger, Markus A.,Macheiner, Peter,Bauer, Pavol,Wolb, Thomas M. The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.6

This paper presents the organisation and the technical structure of a remote controlled laboratory in the field of high dynamic drives and motion control. It is part of the PEMCWebLab project with the goal of providing students with practical experience on real systems in the field of power electronics and drives. The whole project is based on clear targets and leading ideas. A set of experiments can be remotely performed on a real system to stepwise identify a two axes positioning system and to design different cascaded control loops. Each single experiment is defined by its goals, the content of how to achieve them, and a verification of the results as well as the achieved learning outcomes. After a short description of the PEMCWebLab project, the structure of the remote control is presented together with the hardware applied. One important point is error handling as real machines and power electronics are applied. Finally, a selection of experiments is presented to show the graphical user interface and the sequence of the laboratory.

Disorder in quantum critical superconductors

Seo, S.,Lu, X.,Zhu, J. X.,Urbano, R. R.,Curro, N.,Bauer, E. D.,Sidorov, V. A.,Pham, L. D.,Park, T.,Fisk, Z. NATURE PUBLISHING GROUP 2014 NATURE PHYSICS Vol.10 No.2

In four classes of materials the layered copper oxides, organics, iron pnictides and heavy-fermion compounds an unconventional superconducting state emerges as a magnetic transition is tuned towards absolute zero temperature, that is, towards a magnetic quantum critical point(1) (QCP). In most materials, the QCP is accessed by chemical substitution or applied pressure. CeColn(5) is one of the few materials that are 'born' as a quantum critical superconductor(2-4) and, therefore, offers the opportunity to explore the consequences of chemical disorder. Cadmium-doped crystals of CeColn(5) are a particularly interesting case where Cd substitution induces long-range magnetic order(5), as in Zn-doped copper oxides(6,7). Applied pressure globally suppresses the Cd-induced magnetic order and restores bulk superconductivity. Here we show, however, that local magnetic correlations, whose spatial extent decreases with applied pressure, persist at the extrapolated QCP. The residual droplets of impurity-induced magnetic moments prevent the reappearance of conventional signatures of quantum criticality, but induce a heterogeneous electronic state. These discoveries show that spin droplets can be a source of electronic heterogeneity and emphasize the need for caution when interpreting the effects of tuning a correlated system by chemical substitution.

Case RePort : IgG4-Associated Cholangitis Can Mimic Hilar Cholangiocarcinoma

( Victor M Zaydfudim ),( Andrew Y Wang ),( Eduard E De Lange ),( Zimin Zhao ),( Christopher A Moskaluk ),( Todd W Bauer ),( Reid B Adams ) 대한간학회 2015 Gut and Liver Vol.9 No.4

IgG4-associated cholangitis can mimic hilar cholangiocarcinoma. Previously reported patients with IgG4-associated cholangitis mimicking cholangiocarcinoma had elevated serum IgG4 levels and long-segment biliary strictures. However, in the absence of other diagnostic criteria for malignancy, IgG4-associated cholangitis should remain a consideration among patients with normal serum IgG4 and a hilar mass suspicious for cholangiocarcinoma. The presence of a hilar mass and a malignant-appearing biliary stricture in two patients with normal serum IgG4 prompted further evaluation and subsequent concomitant liver and bile duct resection and reconstruction. The diagnosis of IgG4-associated cholangitis was established during the pathologic evaluation of the resected specimens. IgG4-associated cholangitis is a known imitator of hilar cholangiocarcinoma and should be considered in the differential diagnosis even among serologically IgG4-negative patients with a hilar mass prior to operative resection. (Gut Liver 2015;9:556-560)

The Belle II SVD data readout system

Thalmeier, R.,Adamczyk, K.,Aihara, H.,Angelini, C.,Aziz, T.,Babu, V.,Bacher, S.,Bahinipati, S.,Barberio, E.,Baroncelli, Ti.,Baroncelli, To.,Basith, A.K.,Batignani, G.,Bauer, A.,Behera, P.K.,Bergauer, Elsevier BV * North-Holland 2017 Nuclear Instruments & Methods in Physics Research. Vol. No.

<P><B>Abstract</B></P> <P>The Belle II Experiment at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan, will explore the asymmetry between matter and antimatter and search for new physics beyond the standard model.</P> <P>172 double-sided silicon strip detectors are arranged cylindrically in four layers around the collision point to be part of a system which measures the tracks of the collision products of electrons and positrons. A total of 1748 radiation-hard APV25 chips read out 128 silicon strips each and send the analog signals by time-division multiplexing out of the radiation zone to 48 Flash Analog Digital Converter Modules (FADC).</P> <P>Each of them applies processing to the data; for example, it uses a digital finite impulse response filter to compensate line signal distortions, and it extracts the peak timing and amplitude from a set of several data points for each hit, using a neural network.</P> <P>We present an overview of the SVD data readout system, along with front-end electronics, cabling, power supplies and data processing.</P>

Nanoscale electron transport at a stepped Bi₂Se₃ surface

Sebastian BAUER,Hueseyin AZAZOGLU,Christian A. BOBISCH 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8