Name
Grigorash Oleg Vladimirovich
Scholastic degree
•
Academic rank
professor
Honorary rank
—
Organization, job position
Kuban State Agrarian University
Web site url
—
Articles count: 65
In agricultural production, the direction of introduction
of renewable energy for power consumers remote from
the external electrical network is relevant. Here,
prospects are revealed in front of the solar PV stations.
One of the main functional units of solar power is
inverters that convert the DC voltage of the solar
panels into alternating current. The article describes
the advantages and disadvantages of the main methods
of voltage regulation of the autonomous inverters of
solar photovoltaic power plants. We have proposed
new structural designs of autonomous voltage
inverters, described their advantages, features of
design and operation for voltage stabilization. We
suggest stand-alone inverters designed using high
frequency link, which will significantly improve mass
and dimensions parameters of the converter. Due to the
use of single-phase transformer with a rotating
magnetic field in stand-alone inverters, we improve the
efficiency of the converter and the reliability of the
work. Patents of the Russian Federation confirmed the
novelty of technical solutions of the considered
schemes of autonomous voltage inverters. Structural
schematics of the voltage regulators considered in the
article, as well as features of their work, will allow to
increase efficiency of preliminary works on
development of autonomous voltage inverters with
improved operational and technical characteristics for
solar photovoltaic power plants
Modern universities do not have effective
techniques for evaluating the quality of education
of students and effectiveness of teachers' activity
that allows controlling and directing its activities.
We have proposed to perform the quality evaluation
of students preparation based on the results of
intermediate assessments, examinations, and test
results of the teachers, who held their classes. The
article provides analytical expressions for
calculating the quality of the current preparation of
students and the quality of education of graduates,
the effectiveness of teachers in core activities
(educational, methodical and scientific work). In
assessing the quality of education, we have
considered the learning outcomes, employment
potential, i.e. educational and labor activity. The
proposed techniques will increase the objectivity of
the assessment of the quality of graduates’
education in technical universities and the
effectiveness of teachers. This will allow us to
make changes in the organization of educational
process and the content of working programs of
training, educational and methodical and material
and technical support, to change the contents and
technologies of improvement of qualification of the
teaching staff that will contribute to increase
demand for graduates in the labor market
Currently operating in autonomous systems of power
supply DC voltages power sources are secondary
sources for operation devices, protection and control
of generators, motors, stabilizers and inverters have
relatively low operational performance. The work
proposes to improve the weight and the size of power
supplies to apply a high frequency link in their
designs. We provide structural designs and the
peculiarities of operation of secondary power sources
with a high frequency link. This article discusses the
fundamental electrical circuits of pulse regulators,
converters based on resonant inverters and
transformers with rotating magnetic field. The use of
resonant inverters in power sources will significantly
improve their weight and overall dimensions. In
addition, the use of secondary sources of supply for
transformers with rotating magnetic field will
simplify their design and reduce the level of
electromagnetic interference generated by
semiconductor devices. The features of operation of
pulsed regulators and prospective structuralschematics
converters discussed in the article,
performed on resonant inverters and transformers
with rotating magnetic field, will increase the
effectiveness of pre-work on the development of
secondary power sources with improved operational
and technical characteristics for devices of operating,
control and protection
One of the important issues in the design of static
converters of electric power, i.e. rectifiers and
inverters, is to calculate the parameters of the output
and the input filters. Output filters are designed to
improve the quality of output voltage of inverters, and
input filters are created to reduce ripple of the input
voltage of the converter that occur when commuting
power semiconductor devices, and smoothing
fluctuations of the current consumed from the power
supply. The complexity of analytical description of
the harmonic composition of the output and the input
of the voltage rectifiers and inverters makes it
difficult to develop some accurate methods for
calculating the parameters of their filters. At the same
time, considering the discreteness of the number of
possible parameters of real elements of the filter, the
practical value of such techniques with a high analysis
accuracy of the harmonic components is negligible. In
this article, we suggest the technique of the simplified
calculation of output and input filters for passive LC
filters rectifiers and inverters. At the same time, the
practice of mathematical modeling and design of
transducers has shown that the calculations of the
filter parameters for rectifiers and inverters are not
significantly different from each other. Therefore, the
analytical expressions for calculation of the filter
parameters of rectifier used ripple coefficient, and if
necessary the calculation of the filters of the inverter,
instead of the pulse number in the formula can be
substituted with the value of the harmonic; in
addition, we have also taken into account the value of
the load power factor