Scientific Journal of KubSAU

The level of technical development today requires the creation of highly effective, including reliable, uninter-rupted power supply systems. We have shown modern requirements and design features of modern systems of uninterruptible power supply, which should be built on a modular principle. It is shown that the problem of synthesis of systems in a modular approach is addressing three issues: development of the structure of the system subject to the requirements of consumers to quality of power and the allowable time of power outage; determining the required level redundancy of major functional units (blocks, elements) to ensure the required reliability of the system; - ensuring the most effective interconnection of modules, including electromagnetic compatibility, and the rational use during normal and emergency operation of the system. We have proposed new structural solution of the main functional units and uninterrupted power supply systems in modular design. To reduce EMI and improve efficiency uninterruptible power supply systems in the design of static converters we need to use a transformer with a rotating magnetic field. In addition, the prospective current is to be used as a source of renewable energy. Another promising approach is the use of direct frequency converters as voltage stabilizers and frequency of the current

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

Key indicators for employers are the quality of knowledge of graduates and their readiness for practice. The article suggests some methods of assessing the quality of knowledge and labor potential of graduates. Because the quality of training generally depends on the qualification of the faculty, the quality of students' knowledge is to be determined with the results of their learning and the qualification of the teachers who conducted their classes and supervised their final qualifying works. The author's analytical expressions for determining the quality of knowledge and labor potential of graduates, allow employers to choose specialists particularly required for their industry. However, for employers the rate of knowledge and labor potential of graduates of universities are indicative rates. In order to determine the choice of specific graduates, on the University's website starting from the 3rd year of a bachelor degree, we should post the information about the rating of individual students on educational and labor activity. The ratios determine the quality of knowledge of graduates and their labor potential, as well as reviews of employers should be the main indicators for the Ministry of education and science of the Russian Federation, on the basis of which we may assess the effectiveness of the universities, determine their ranking and generate a state order for training of specialists in higher education institutions

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

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

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

The article reveals the basic principle of stabilizing the DC voltage, providing automatic control of electrical devices and electrical equipment, control systems, control and protection, etc. There are functional diagrams (operated and promising) of DC voltage stabilization with a device included in the input and output power circuits of the rectifier, and a new structural solution to a functional circuit of the rectifier made of two controllable power electronic devices and transformer with midpoint. The article lists peculiarities of the circuits of the voltage regulators and their main advantages and disadvantages. We have reviewed functional diagrams of existing and new solutions of the stabilizers and the characteristics of their work; it will increase the effectiveness of pre-project works on the development of stabilizers of the DC voltage with improved performance characteristics. This article might be useful for post-graduates and research workers who are involved in the development of DC voltage stabilizers

The article discusses the features of design and operation in the different modes of functioning of autonomous hybrid power plants based on renewable and traditional energy sources. We have given a structural scheme of such a plant. It is shown that the algorithm of the system in the autumn-winter period should be adjusted according to the monthly monitoring; and standby generator of independent source can be run at a deeper discharge of batteries. It is known that the most expensive and the weakest link in the solar PV plants is rechargeable battery. In addition, the larger the number they have in the system, the more complicated the fulfillment of all conditions of proper operation is. We have proposed to extend the lifetime of batteries through the use of passive balancing, which allows to increase the reliability of operation and reduce the cost. It is shown that a real possibility of improving the technical and economic performance of autonomous hybrid power plants is their execution on the basis of solar photovoltaic power plants. We have also discussed the features of construction and operation of hybrid power plants, which will increase the efficiency of preliminary works on development of high-performance structural circuit design of the stations

Perspectives of science in high schools were always defined by prospects of development of scientific teams. The author proposes to divide (depending on the contents of research targets) unities of the research process and the results of research teams of the Department into three categories: a scientific group, a scientific school and a leading scientific school. Research teams are characterized by not only quantitative and qualitative composition, but the annual results. We reveal functional duties of leaders of research teams and the head of the Department for their effective management. One of the main tasks of the Department is to create conditions for the disclosure of scientific and creative abilities of students. The article describes general concepts and the content of scientific researches, including the formulation of themes, goals and objectives of the research, as well as the basics of research methodologies required for students in conducting the research work. The structure of research groups of the Department, the content of their work, the main functional responsibilities of heads of scientific disciplines and the head of the Department, basics of scientific research methodology discussed in the article, will increase the organization's effectiveness and the efficiency of R & D Department

The article discusses the structural schematics of solar energy systems, providing guaranteed power supply to electricity consumers with priority for consumers of the 1st category. The work describes main functions performed by modern energy systems. It is shown that nowadays solar power systems of uninterruptable power supply are classified into three types: independent; hybrid (combined); intellectual. We have given the structural scheme of solar systems power systems of uninterruptable power supply and the features of their work. The article describes a monitoring system, carrying out functions of control and measurement of parameters of the power system depends on its performance. The economic performance of a solar power system has been influenced essentially by the cost of solar and accumulator batteries. The principal technical characteristics of modern solar and regular batteries of the best companies were compared. We have also given recommendations for improving the operational characteristics of solar energy systems of guaranteed power supply, in which special attention is paid to technical characteristics of the main functional elements of the system, including electromagnetic compatibility