scholarly journals State and Space Vectors of the 5-Phase 2-Level VSI

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4385
Author(s):  
Jan Iwaszkiewicz ◽  
Adam Muc

The paper proposes a general description system of the five-phase two-level inverter. The two base methods are presented and discussed. The first one is based on the standard space vector transformation, while the other uses state vectors which enable the definition of the basic physical quantities of the inverter: current and voltage. The proposed notation system offers a general simplification of vector identification. It comprises a standardized proposal of notation and vector marking, which may be extremely useful for the specification of inverter states. The described notation system makes it possible to reach correlation between state and space vectors. It presents space and state vectors using the same digits. These properties suggest that the proposed notation system is a useful mathematical tool and may be really suitable in designing control algorithms. This mathematical tool was verified during simulation tests performed with the use of the Simulation Platform for Power Electronics Systems—PLECS.

2021 ◽  
Vol 19 ◽  
pp. 641-646
Author(s):  
Jan Iwaszkiewicz ◽  
◽  
Adam Muc

The paper describes an example of the vector control strategy applied to five-phase two-level inverters. Two base methods are discussed. The first one is based on the standard space vector transformation, while the other uses state vectors which enable the definition of the basic physical quantities of the inverter. The proposed notation system offers an universal simplification of vector identification. It comprises a standardized proposal of notation and vector marking. This tool may be really useful for the description of inverter states and makes it possible to reach correlation between state and space vectors. All vectors are defined by use of the same digits. The proposed mathematical tool has been verified during simulation tests performed with the use of the PLECS program.


In this part will be given a general description of the absorption bands found in these three gases, together with curves showing their occurrence in the region up to 17 μ, and evaluations of the maxima of the absorption bands. In Part IV the relationships of the bands to each other in one gas, and to corresponding bands in the other gases, where these occur, will be dicussed. A description of the apparatus is given in Part I, and of its calibration and of the general procedure in part II, Which also give the methods of obtaining the gases pure. It is only necessary, therefore, to say here that in order to get the best definition of which this prism instrument is capable, the galvanometer was maintained at its highest sensitiveness, the spectrometer slits were the galvanometer scale, the longer tubes were selected for the examination of faint bands and the shorter tubes were selected for the examination of faint bands and the shorter tubes for strong bands, and the exploration was conducted at pressures varying from 1 to 1/16 or 1/32 atmosphere.


Author(s):  
K. T. Tokuyasu

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).


Author(s):  
Juan de Lara ◽  
Esther Guerra

AbstractModelling is an essential activity in software engineering. It typically involves two meta-levels: one includes meta-models that describe modelling languages, and the other contains models built by instantiating those meta-models. Multi-level modelling generalizes this approach by allowing models to span an arbitrary number of meta-levels. A scenario that profits from multi-level modelling is the definition of language families that can be specialized (e.g., for different domains) by successive refinements at subsequent meta-levels, hence promoting language reuse. This enables an open set of variability options given by all possible specializations of the language family. However, multi-level modelling lacks the ability to express closed variability regarding the availability of language primitives or the possibility to opt between alternative primitive realizations. This limits the reuse opportunities of a language family. To improve this situation, we propose a novel combination of product lines with multi-level modelling to cover both open and closed variability. Our proposal is backed by a formal theory that guarantees correctness, enables top-down and bottom-up language variability design, and is implemented atop the MetaDepth multi-level modelling tool.


2018 ◽  
Vol 6 (4) ◽  
pp. 401-428
Author(s):  
Miriam R. Lowi

Studies of identity and belonging in Gulf monarchies tend to privilege tribal or religious affiliation, if not the protective role of the ruler as paterfamilias. I focus instead on the ubiquitous foreigner and explore ways in which s/he contributes to the definition of national community in contemporary gcc states. Building upon and moving beyond the scholarly literature on imported labor in the Gulf, I suggest that the different ‘categories’ of foreigners impact identity and the consolidation of a community of privilege, in keeping with the national project of ruling families. Furthermore, I argue that the ‘European,’ the non-gcc Arab, and the predominantly Asian (and increasingly African) laborer play similar, but also distinct roles in the delineation of national community: while they are differentially incorporated in ways that protect the ‘nation’ and appease the citizen-subject, varying degrees of marginality reflect Gulf society’s perceptions or aspirations of the difference between itself and ‘the other(s).’


The vapour pressure theory regards osmotic pressure as the pressure required to produce equilibrium between the pure solvent and the solution. Pressure applied to a solution increases its internal vapour pressure. If the compressed solution be on one aide of a semi-permeable partition and the pure solvent on the other, there is osmotic equilibrium when the com-pression of the solution brings its vapour pressure to equality with that of the solvent. So long ago as 1894 Ramsay* found that with a partition of palladium, permeable to hydrogen but not to nitrogen, the hydrogen pressures on each side tended to equality, notwithstanding the presence of nitrogen under pressure on one side, which it might have been supposed would have resisted tin- transpiration of the hydrogen. The bearing of this experiment on the problem of osmotic pressure was recognised by van’t Hoff, who observes that "it is very instructive as regards the means by which osmotic pressure is produced." But it was not till 1908 that the vapour pressure theory of osmotic pressure was developed on a finu foundation by Calendar. He demonstrated, by the method of the "vapour sieve" piston, the proposition that “any two solutions in equilibrium through any kind of membrane or capillary surface must have the same vapour pressures in respect of each of their constituents which is capable of diffusing through their surface of separation"—a generalisation of great importance for the theory of solutions. Findlay, in his admirable monograph, gives a very complete account of the contending theories of osmotic pressure, a review of which leaves no doubt that at the present moment the vapour pressure theory stands without a serious rival Some confusion of ideas still arises from the want of adherence to a strict definition of osmotic pressure to which numerical data from experimental measurements should he reduced. Tire following definitions appear to be tire outcome of tire vapour pressure theory :— Definition I.—The vapour pressure of a solution is the pressure of the vapour with which it is in equilibrium when under pressure of its own vapour only.


1935 ◽  
Vol 8 (2) ◽  
pp. 151-173 ◽  
Author(s):  
W. B. Wiegand ◽  
J. W. Snyder

Abstract General Description.—The rubber pendulum is one of two devices (Wiegand, Trans. Inst. Rubber Ind., 1, 141 (1925)) which, by employing the Joule effect, constitute rubber heat engines in that they continuously convert heat into mechanical work. In Fig. 1 is shown the original pendulum. It consists of an ordinary pendulum of slow period fitted with a rubber band, one end of which is attached to the bob; the other to the upright support. This rubber band is stretched to four or five times its original length. Behind the upright is a metal shield so arranged that when the bob has reached the extremity of its swing the rubber band is clear of the shield, during the rest of the oscillation being in its shadow. Behind the pendulum and shield is an electric heating element with a copper reflector. The pendulum is started by displacement from the center towards one or other extremity. As this is done the rubber band is increased in length. At the extremity of the oscillation the stretch band is exposed to the radiant heat from the element, the Joule effect is brought into play and the band tends to shrink, thus pulling back the bob. Directly the band moves back within the shadow of the shield it cools, relaxes, and so allows the bob to swing out to the other side. Thereupon the band is once more heated up, contracts and so repeats the oscillation, which continues as long as the heat energy is supplied. When the electric current is turned off the pendulum dies down.


1994 ◽  
Vol 4 (1) ◽  
pp. 181-198 ◽  
Author(s):  
Bijan Vahabzadeh

Euclid's definition of proportional magnitudes in the Fifth Book of the Elements gave rise to many commentaries. We examine closely two of these commentaries, one by al-Jayyānī (11th century) and the other by Saunderson (18th century). Both al-Jayyānī and Saunderson attempted to defend Euclid's definition by making explicit what Euclid had only implied. We show that the two authors explain Euclid's position in a virtually identical manner.


1984 ◽  
Vol 49 (1) ◽  
pp. 47-50 ◽  
Author(s):  
Frederic B. Fitch

In [3] a definition of negation was presented for the system K′ of extended basic logic [1], but it has since been shown by Peter Päppinghaus (personal communication) that this definition fails to give rise to the law of double negation as I claimed it did. The purpose of this note is to revise this defective definition in such a way that it clearly does give rise to the law of double negation, as well as to the other negation rules of K′.Although Päppinghaus's original letter to me was dated September 19, 1972, the matter has remained unresolved all this time. Only recently have I seen that there is a simple way to correct the definition. I am of course very grateful to Päppinghaus for pointing out my error in claiming to be able to derive the rule of double negation from the original form of the definition.The corrected definition will, as before, use fixed-point operators to give the effect of the required kind of transfinite induction, but this time a double transfinite induction will be used, somewhat like the double transfinite induction used in [5] to define simultaneously the theorems and antitheorems of system CΓ.


2020 ◽  
pp. 1-37
Author(s):  
MANISHA SETHI

Abstract A bitter debate broke out in the Digambar Jain community in the middle of the twentieth century following the passage of the Bombay Harijan Temple Entry Act in 1947, which continued until well after the promulgation of the Untouchability (Offences) Act 1955. These laws included Jains in the definition of ‘Hindu’, and thus threw open the doors of Jain temples to formerly Untouchable castes. In the eyes of its Jain opponents, this was a frontal and terrible assault on the integrity and sanctity of the Jain dharma. Those who called themselves reformists, on the other hand, insisted on the closeness between Jainism and Hinduism. Temple entry laws and the public debates over caste became occasions for the Jains not only to examine their distance—or closeness—to Hinduism, but also the relationship between their community and the state, which came to be imagined as predominantly Hindu. This article, by focusing on the Jains and this forgotten episode, hopes to illuminate the civilizational categories underlying state practices and the fraught relationship between nationalism and minorities.


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