Vishnev Timur
Electrical engineering
Speciality: Electromechanical systems of automation and electrical drive
Leader of work: Shymyatskiy V.M.
Abstract
Theme of master's work: «The research of modes of operations of direct frequency transformer»
Actuality of theme
From the moment of
appearance of electrical drive (ED) of alternating current as well as ED
of constant current one of major questions is a question of adjusting of
frequency of its rotation. At present there is stormy development of
semiconductor transformer technique, which in its turn enables to apply
the new methods of decision of this question.
At present the drive of
direct current is widely used in industry, and also system of adjusting of
their speed on the basis of tiristor transformers of voltage (TTV).
However there is a question of replacement of such systems of adjusting of
speed on the systems, in basis of which an asynchronous engine lies. It is
urgent. Such systems consist of transformer of frequency (TF) and
asynchronous engine (AE). They allow to get more deep adjusting of speed,
i.e. to increase an adjusting range.
In its turn TF is divided into 2
groups: with the link of direct current and direct (DTF). The transformers
of frequency with the link of direct current allow to regulate frequency
of feeding voltage in the range (0-2*fc) Hertz, where fc is industrial
frequency of 50 Hertz. Such range of adjusting gives this group of
transformers advantage above DTF, because the last ones support the
nominal loading in the range (0-fc/2) Hertz. However the defect of TF with
the link of direct current is a presence of rectifier and inverter, at the
expense of that the double transformation of energy takes place, which
results in lowering of coefficient of efficiency (CE) of the system on its
basis. DTF in its turn differs with simplicity of design that allows the
system on its basis to have CE higher than at the system on the basis of
TF with the link of direct current.
It follows from aforesaid, that
the development of methods and ways which will allow to replace the TF-AE
system on the DTF-AE systems.
Aims and tasks of research
The aim of the work
is development of the system of feed of AE, which consists of static
electromagnetic transformer (SEMT) and DTF. This system in a prospect will
allow to replace the systems with the use of TF with the link of direct
current and to extend the range of output working frequencies of DTF.
Tasks, formulated for achievement of the
aim:
1. To consider the theoretical questions of design and range
of the use of DTF.
2. To develop mathematical model of feed of AE from
DTF.
3. To represent the diagrams of work of mathematical model at
output frequency of 25 Hertz.
4. To show adequacy of the obtained
results to the real descriptions.
5. To consider the variant of feed
of AE from the matrix transformer of frequency.
6. To develop
mathematical model of the key, which in future will allow to create the
mathematical model of matrix transformer of frequency for research in the
real modes of work.