661 research outputs found
Passive Power Filters
Power converters require passive low-pass filters which are capable of
reducing voltage ripples effectively. In contrast to signal filters, the
components of power filters must carry large currents or withstand large
voltages, respectively. In this paper, three different suitable filter
structures for d.c./d.c. power converters with inductive load are introduced.
The formulas needed to calculate the filter components are derived step by step
and practical examples are given. The behaviour of the three discussed filters
is compared by means of the examples. Practical aspects for the realization of
power filters are also discussed.Comment: 25 pages, contribution to the 2014 CAS - CERN Accelerator School:
Power Converters, Baden, Switzerland, 7-14 May 201
Thermal Design of Power Electronic Circuits
The heart of every switched mode converter consists of several switching
semiconductor elements. Due to their non-ideal behaviour there are ON state and
switching losses heating up the silicon chip. That heat must effectively be
transferred to the environment in order to prevent overheating or even
destruction of the element. For a cost-effective design, the semiconductors
should be operated close to their thermal limits. Unfortunately the chip
temperature cannot be measured directly. Therefore a detailed understanding of
how losses arise, including their quantitative estimation, is required.
Furthermore, the heat paths to the environment must be understood in detail.
This paper describes the main issues of loss generation and its transfer to the
environment and how it can be estimated by the help of datasheets and/or
experiments.Comment: 17 pages, contribution to the 2014 CAS - CERN Accelerator School:
Power Converters, Baden, Switzerland, 7-14 May 201
T_0*-compactification in the hyperspace
A *-compactification of a T0 quasi-uniform space (X,U) is a compact T0 quasi-uniform space (Y,V) that has a T(V∨V−1)-dense subspace quasi-isomorphic to (X,U). In this paper we study when the hyperspace with the Hausdorff–Bourbaki quasi-uniformity is *-compactifiable and describe some of its *-compactifications.Kunzi, HA.; Romaguera Bonilla, S.; Sanchez Granero, MA. (2012). T_0*-compactification in the hyperspace. Topology and its Applications. 159:1815-1819. doi:10.1016/j.topol.2011.06.064S1815181915
Quasi-pseudo-metrization of topological preordered spaces
We establish that every second countable completely regularly preordered
space (E,T,\leq) is quasi-pseudo-metrizable, in the sense that there is a
quasi-pseudo-metric p on E for which the pseudo-metric p\veep^-1 induces T and
the graph of \leq is exactly the set {(x,y): p(x,y)=0}. In the ordered case it
is proved that these spaces can be characterized as being order homeomorphic to
subspaces of the ordered Hilbert cube. The connection with
quasi-pseudo-metrization results obtained in bitopology is clarified. In
particular, strictly quasi-pseudometrizable ordered spaces are characterized as
being order homeomorphic to order subspaces of the ordered Hilbert cube.Comment: Latex2e, 20 pages. v2: minor changes in the proof of theorem 2.
Logic Programs for Primitive Recursive Sets
Meyer and Ritchie have previously given a description of primitive recursive functions by loop-programs. In this paper a class of logic programs is described which computes the primitive recursive sets on Herbrand universes. Furthermore, an internal description of primitive recursive functions and sets on Herbrand universes is give
A note on uniform ordered spaces
We characterize the generalized ordered topological spaces X for which the uniformity (X) is convex. Moreover, we show that a uniform ordered space for which every compatible convex uniformity is totally bounded, need not be pseudocompac
- …