The article presents a solution to the problem of determining the inductance of the input filter choke for a high-voltage power converter (HV). The HV based on series-connected power input units are considered. Expressions for calculating the inductance of the input filter choke depending on the specified level of ripple input current consumption, the switching frequency of power transistors, the control algorithm and the number of series-connected power input blocks are obtained. Power circuits of the HV with a different number of power input units connected in series are shown. This article is useful for specialists who are engaged in the development of HV, and, in particular, the design of on-board static converters for rolling stock with a voltage of 3000 V DC of the contact network.Keywords: high-voltage DC converter, input filter choke inductance, input current consumption ripple, control algorithm, boost converter.
The program fortraction and external power supply systems calculations is based on two main principles of large power supply systems theory: tensor analysis and diakoptics. In the issuance the compact formulas for balancing current calculations were received, then were defined all parameters of design conditions. The development result is the "beam" equivalent of electrified district. The merit of the author is that the program for calculation of the traction power supply system was developed with account taken of external power supply system mode. It may be used for educational purposes as well as in design practice and research work. The program PACK-05K designed to calculate instant circuits, short-circuit currents in all elements of the network. The advantages of the program are the simplicity of inputting initial data and correcting them when changing the design mode. The information output is formed in the form of a resistance matrix of the calculated equivalent circuit, the graph of node voltages, the matrix of currents in the traction network and power losses in the circuit elements.Keywords: program for calculation, tensor analysis, diakoptics, "beam" equivalent, equivalent, instant circuit, resistance matrix, node currents and voltages.
The paper considers the development trend of modern transport taking into account the reduction in the price of electrochemical energy storage. The analysis of the previously investigated factors affecting the service life of the storage battery is carried out. The influence of an additional factor associated with the specificity of the traction electric drive operation modes is assumed – the alternation of short charge and discharge modes when an electric vehicle is moving. To assess the aging of the lithium battery, the WLTC driving cycle was taken as a basis, in accordance with which the load on the storage unit of the electric vehicle was formed. A Nissan Leaf with a power supply unit with an energy consumption of 24 kW∙h was taken as a test sample. The current diagrams for a single battery cell are calculated, the minimum, average and maximum currents, as well as the durations of the traction, braking and stopping modes in various control modes of the electric rolling stock are given. Equivalent current diagrams have been obtained that simulate the finding of the vehicle in each mode of the WLTC cycle.Keywords: electric transport, electrochemical energy storage, lithium battery, driving cycles, energy recovery.
At the cold countries, the operation of electric vehicles is difficult in the winter when temperatures are below zero. A low ambient temperature increases the internal resistance of the battery, slowing down diffusion and reducing the ionic conductivity of the electrolyte, which reduces the energy and power of the battery. These limitations for lithium-ion batteries remain one of the main barriers to their widespread use in the energy systems and transport, in Russia, Europe and other northern regions. Until now, research on the low-temperature behavior of lithium-ion cells provided little important information because they were only extended to low-capacity batteries. This article presents the experimental data of testing the lithium-iron-phosphate (LiFePO4) battery LT-LFP101.2 manufactured by Liotech in various temperature ranges. The experimental research process included charging at ambient temperature, subsequent cooling of the battery in the chamber, and a discharge cycle at a given temperature.Keywords: lithium iron phosphate battery; charging and discharging modes; low-temperature, internal resistance, capacity.
The article presents the results of the development and implementation of the method for controlling the temperature conditions of the heater of the sensitive element of the planar type oxygen sensor. The work was prepared with the support of the grant of the President of the Russian Federation NSh-2515.2020.8Keywords: car; electrical onboard systems; oxygen sensor; temperature control.
The technical willingness of deep-water vehicles, collectively determined by the actual state of its systems and components, is the most important aspect of the safety of operations at various depths. The power capacity of aboard power sources determines not only the duration of the campaign and the autonomy of inhabited underwater vehicles, but also the ability to perform various underwater technical work with the use of additional equipment. For this reason, regular preventive measures regarding aboard power supplies have a high priority. In this paper, time diagrams of discharge and charge the individual sections of inhabited underwater vehicles batteries are studied, and their technical condition is evaluated.Keywords: technical willingness, aboard supply sources, deep-water equipment, power capacity.
The paper studies numerical indicators of reliability of microprocessor relay protection devices for various schemes of local area network (LAN) organization at the AC railway power supply system. The relevance of the research is due to the active modernization of the energy complex through the introduction of information and digital technologies in process control systems. Due to the current lack of a regulatory framework for assessing the reliability of digital relay protection and automation systems in Russian railways, this paper uses connection schemes and technological design requirements for digital power substations, which allows adapting their design for AC railway traction substations and comparing the reliability indicators of new and existing (traditional) schemes, which is a scientific novelty. Step-by-step examples of drawing up topological replacement schemes for reliability are given, modeling and fault tree analysis are performed, taking into account the reliability indicators of elements on the example of an existing traction substation.Keywords: reliability, digital substation, relay protection, fault tree.
The article deals with the issues related to the development of an expert system of self-diagnosis, in relation to the power part of the electric drive of the car. The procedure of forming the database of the expert system is described. The functional diagram of the integrated self-diagnosis system is given.Keywords: car, electric drive, diagnostics, expert system, battery.
The article presents the results of experimental studies of the noise immunity of an electronic control system for an internal combustion engine of a passenger car, as well as an electronic control system for an automated transmission. The work was prepared with the support of the grant of the President of the Russian Federation NSh-2515.2020.8Keywords: car; onboard electrical complex; electromagnetic compatibility.