The article provides an overview and comparative analysis of various types of batteries, including the most modern type—lithium-ion batteries. Currently, lithium-ion batteries (LIB) are widely used in electrical complexes and systems, including as a traction battery for electric vehicles. Increasing the service life of the storage devices used today is an important scientific and technical problem due to their rapid wear and tear and high cost. This article discusses the main approaches and methods for researching the LIB resource. First of all, a detailed analysis of the causes of degradation was carried out and the processes occurring in lithium-ion batteries during charging, discharging, resting and difficult operating conditions were established. Then, the main factors influencing the service life are determined: charging and discharging currents, self-discharge current, temperature, number of cycles, discharge depth, operating range of charge level, etc. when simulating a real motion process. The work considers the battery management systems (BMS) that take into account and compensate for the influence of the factors considered. In the conclusion, the positive and negative characteristics of the presented methods of scientific research of the residual life of LIB are given and recommendations are given for the choice of practical solutions to engineers and designers of batteries. The work also analyzed various operating cycles of electric transport, including heavy forced modes, extreme operating modes (when the amount of discharge and discharge of batteries is greater than the nominal value) and their effect on the degradation of lithium-ion batteries.

Based on the development of the theory of reactive power and distortion power, starting with the works of Fryze and Budeanu, it has been found that the contradictions in the definition of the components of inactive powers are caused by errors in the introduced intermediate concepts and corresponding calculations when switching to nonlinear and non-sinusoidal AC circuits. The materials of the works of modern researchers and the numerical calculations carried out made it possible to trace the differences between reactive power and distortion power, to confirm the orthogonality properties of the active, reactive power, and distortion power components. The paper defines the conditions for achieving a power balance in an AC network with nonlinear loads, compiled and tested criteria leading to the absence of distortion power in a single-phase AC network. Using the time base of the projection of the generalized vectors in vector diagrams, it is shown that compliance with the criteria for the absence of distortion power does not determine the mutual similarity of the voltage curve with the current curve for a nonlinear load. It has been found that the well-known term “distortion power” has an unfortunate wording, since this power, although it characterizes the interaction of harmonics of currents and voltages with different ordinal numbers, is not determined by the visual similarity or the degree of distortion of the load current waveforms relative to the supply voltage curve.

The work is devoted to methods for increasing the energy efficiency of photovoltaic modules. Various algorithms for determining the maximum power points and their application to obtain the maximum possible efficiency when using solar panels are considered. The principles of the operation of algorithms are described; their advantages and disadvantages are indicated. Their comparison was carried out according to the main significant parameters. The most suitable algorithm for application at a weather station has been selected.

No abstract

Abstract-Lithium-ion battery (LIB) technology further enabled the information revolution by powering smartphones and tablets, allowing an unprecedented performance of these devices against reasonable cost. Currently, this battery technology is on the verge of carrying the revolution in road transport and energy storage of renewable energy. However, to fully succeed in the latter, a number of hurdles still need to be taken. Battery performance and lifetime constitute a bottleneck for electric vehicles as well as stationary electric energy storage systems to penetrate the market. Electrochemical battery models are one of the engineering tools which could be used to enhance their performance. These models can help to optimize the cell design and the battery management system. In this study, the authors evaluate the ability of the Porous Electrode Theory (PET) to predict the effect of changing positive electrode density in the overall performance of Li-ion battery cells. It can be concluded that Porous Electrode Theory (PET) is capable of predicting the difference in cell performance due to a changing positive electrode density.

reliable power saving electric drive of wide application is shown. Functional scheme of it was designed and shown. The adjustable-ftequency electric drive (FED) is the complex consisting of the electric motor of an ahemate current with this dnve set in motion by the gear and a frequency shifter.Controlled-velocity electric drives are widely applied in an agriculture on mechanisms where regulating any physical parameter is required: velocities, force, temperatures, pressures [l].Principles of fiequent regulating of electric drives of mechanisms use in the pump unit i n system of suburban water service. It is known, that it is the major area of application of electric drives since for swapping pure and sewage in Russia it is outplayed up to 12 billion kWh the electric power [2].To give water to the crane of using equipment, it is necessary to create a necessary pressure X on an exit of a pump station. Its magnitude develops of two components:-Static Hc -an equal variance of absolute elevations of the user had above others and a pump station, plus necessary pressure for a user;-Dynamic S, necessary for overcoming a flow ~c t i o n of a pipe manifold to a current of water, and depending on magnitude of water-analysis Q .Thus, a necessary pressure on an exit of a pump station H = Hc+ S .Q2(1) Expression (I) characterizes a water service facilities, uniquely defining a quantity a necessary pressure on an exit of a pump station for water service of the most longdistance user depending on magnitude of water-analysis from system.Pump delivery is determined %om product of magnitude of a pressure ensured by it an appropriate magnitude of feed, and is actually proportional to rotation rate of the pump rotor Assuming, that the water service is ensured with one pump unit selected on the maximum pressure and productivity (the most widespread altemative), it is possible to consider, that at magnitudes of water-analysis smaller maximum this pump will create an overpressure in system H . This hazardous to a pipe manifold pressure can in exceed a necessary pressure some times.For extirpation with this phenomenon the method of a throttIe control is most spreader -the overpressure is erased on an output bolt fiom a pump station [l]. At its cover there is a resistance to a current of water. The performance of system thus to the given magnitude of water-analysis, matches to the full to a pump characteristic.The problem for pumps and ventilators is decided by application instead of a choking and a method powered up is switched off' speed control. Thus foIloWing conditions are satisfied: 1. Expenditure is proportional to revolutions per minute, Q E o, [mx]* 2. Pressure is proportional to quadrate of revolutions K2l. per minute, H E 02, 3 . The power input is proportional to a cube of revolutions per minute, P s 03, [VY] . Thus, if required expenditure makes 80 % fiom nominal the required revolutions ,per minute make only 80 % eom nominal; pressure drops up to 64 % fkom nominal; the power input is equal 5 1 % from nominal.Application of ...

No abstract

No abstract