scholarly journals ANALYSIS OF CHARACTERISTICS OF ELECTRIC BRAKING SYSTEMS

2020 ◽  
Vol 1 (154) ◽  
pp. 2-7
Author(s):  
V. Herasymenko ◽  
V. Pliuhin ◽  
М. Shpika
Keyword(s):  
Electric Motor ◽  
High Frequency ◽  
Frequency Converter ◽  
Variable Structure ◽  
Energy Performance ◽  
Energy Characteristics ◽  
Braking System ◽  
Dc Motors ◽  
In Series ◽  
Electric Braking

The technical and energy characteristics of the most commonly used electrical braking systems are analyzed, their disadvantages are indicated. An electrical braking system with variable structure and DC motors with the best technical and energy performance is proposed. In the braking mode, the motors operate in series excitation, and the current in the excitation windings is controlled by a DC-DC converter. Keywords: electric motor, excitation windings, electrical braking, energy performance, high frequency converter.

scholarly journals Improving the Energy Performance of Traction Electric Drive Vehicles in Solving Electric Braking

2021 ◽  
Vol 20 (1) ◽  
pp. 52-57
Author(s):  
V. Herasymenko ◽  
N. Shpika ◽  
M. Smyrnyi ◽  
D. Khuruzha
Keyword(s):  
Electrical Energy ◽  
Energy Performance ◽  
Storage Device ◽  
Power Circuit ◽  
Storage Devices ◽  
Electric Drives ◽  
Braking System ◽  
Dc Motors ◽  
Electric Braking ◽  
Technical Solutions

The effectiveness of the electric braking system largely depends on how the braking is carried out, whether the braking characteristics that it forms are acceptable for a given vehicle, how simple and reliable the technical solutions embedded in the system are, and where the braking energy is used. With electric braking, it is possible not only to extinguish the electrical energy on the braking resistor, but also to send it back to the storage device and again use it in traction mode. This paper analyzes the most common methods of electric braking used in electric braking systems for traction electric drives that are in operation on vehicles. As the main criterion for evaluating the method of electric braking, its energy indicators are selected. The results of scientific research of the proposed new method of electric braking, which provides better energy performance and new technical solutions for its implementation, are considered. When implementing this method, DC motors are operated by sequential excitation generators. The current in the field windings is regulated by a DC-DC-converter. Energy in the power circuit is accumulated in storage devices and used in traction mode. When the storage devices are filled, the energy in the power circuit is extinguished by the braking resistor, and the energy from the output of the DC-DC-converter is used for own needs. In this case, braking characteristics are formed as in generators of independent excitation. To increase the braking efficiency at low speeds, it is necessary to smoothly regulate the resistance of the braking resistors by shunting them with transistor switches.

scholarly journals A High Frequency Converter for EV Application

2018 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
G. Kannan
Keyword(s):  
High Frequency ◽  
Frequency Converter ◽  
Switching Losses ◽  
Auxiliary Power ◽  
Electrical Vehicle ◽  
In Series ◽  
Alternative Power ◽  
Green Transportation ◽  
Dc Bus ◽  
Electric Traction

<p>An electrical vehicle (EV) is advancing as alternative power trains for green transportation. the DC–DC converter for auxiliary power supply of electric loads .In this paper presented  a new topologyof  high frequency converter for electric vehicle was proposed,This converter has to be capable of handling the energy transfer from the 28V DC bus and the 550 high voltage DC bus (used for the electric traction). The control strategy is phase shift of the full bridge converter. Using this topology we reduce the switching losses. Conventional converter at two levels of voltage by only one full bridge converter using two planar transformers in high frequency the primary are coupled in parallel and the secondary are in series. We minimized the size and the weight of the converter. The high frequency converter advantages in terms of cost, efficiency, flexibility, and increased due to the possibility of easy synchronous rectification implementation.<strong><em></em></strong></p>

scholarly journals Categories and Frequency: Cognition Verbs in Spanish Subject Expression

Languages ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 126
Author(s):  
Catherine E. Travis ◽  
Rena Torres Cacoullos
Keyword(s):  
High Frequency ◽  
Fixed Effects ◽  
Variable Structure ◽  
Semantic Classes ◽  
Variation Patterns ◽  
Subject Pronoun ◽  
Subject Expression ◽  
Linguistic Categories ◽  
Analysis Of Variation ◽  
New Evidence

Are semantic classes of verbs genuine or do they merely mask idiosyncrasies of frequent verbs? Here, we examine the interplay between semantic classes and frequent verb-form combinations, providing new evidence from variation patterns in spontaneous speech that linguistic categories are centered on high frequency members to which other members are similar. We offer an account of the well-known favoring effect of cognition verbs on Spanish subject pronoun expression by considering the role of high-frequency verbs (e.g., creer ‘think’ and saber ‘know’) and particular expressions ((yo) creo ‘I think’, (yo) no sé ‘I don’t know’). Analysis of variation in nearly 3000 tokens of unexpressed and pronominal subjects in conversational data replicates well-established predictors, but highlights that the cognition verb effect is really one of 1sg cognition verbs. In addition, particular expressions stand out for their high frequency relative to their component parts (for (yo) creo, proportion of lexical type, and proportion of pronoun). Further analysis of 1sg verbs with frequent expressions as fixed effects reveals shared patterns with other cognition verbs, including an association with non-coreferential contexts. Thus, classes can be identified by variation constraints and contextual distributions that are shared among class members and are measurably different from those of the more general variable structure. Cognition verbs in variable Spanish subject expression form a class anchored in lexically particular constructions.

scholarly journals Insulation Life Span of Low-Voltage Electric Motors—A Survey

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1738
Author(s):  
Vanessa Neves Höpner ◽  
Volmir Eugênio Wilhelm
Keyword(s):  
Life Span ◽  
Electric Motor ◽  
Low Voltage ◽  
Frequency Converter ◽  
Rate Of Change ◽  
High Rate ◽  
Switching Frequency ◽  
Electric Motors ◽  
Frequency Converters ◽  
High Switching Frequency

The use of static frequency converters, which have a high switching frequency, generates voltage pulses with a high rate of change over time. In combination with cable and motor impedance, this generates repetitive overvoltage at the motor terminals, influencing the occurrence of partial discharges between conductors, causing degradation of the insulation of electric motors. Understanding the effects resulting from the frequency converter–electric motor interaction is essential for developing and implementing insulation systems with characteristics that support the most diverse applications, have an operating life under economically viable conditions, and promote energy efficiency. With this objective, a search was carried out in three recognized databases. Duplicate articles were eliminated, resulting in 1069 articles, which were systematically categorized and reviewed, resulting in 481 articles discussing the causes of degradation in the insulation of electric motors powered by frequency converters. A bibliographic portfolio was built and evaluated, with 230 articles that present results on the factors that can be used in estimating the life span of electric motor insulation. In this structure, the historical evolution of the collected information, the authors who conducted the most research on the theme, and the relevance of the knowledge presented in the works were considered.

Multi-band planar diplexers with sub-sets of frequency-contiguous transmission bands

2021 ◽  
pp. 1-11
Author(s):  
Roberto Gómez-García ◽  
Li Yang ◽  
José-María Muñoz-Ferreras ◽  
Dimitra Psychogiou
Keyword(s):  
High Frequency ◽  
Transmission Band ◽  
Satellite Communications ◽  
Proof Of Concept ◽  
Transmission Zeros ◽  
Cascade Connection ◽  
Coupling Techniques ◽  
In Series ◽  
Mobile Satellite ◽  
Multi Band

Abstract A class of multi-band planar diplexer with sub-sets of frequency-contiguous transmission bands is reported. Such a radio frequency (RF) device is suitable for lightweight high-frequency receivers aimed at multi-band/multi-purpose mobile satellite communications systems. It consists of two channelizing filters, each of them being made up of the in-series cascade connection of replicas of a constituent multi-passband/multi-embedded-stopband filtering stage. This building filtering stage defines a multi-passband transfer function for each channel, in which each main transmission band is split into various sub-passbands by the multi-stopband part. In this manner, each split passband gives rise to several sub-passbands that are imbricated with their counterpart ones of the other channel. The theoretical RF operational principles of the proposed multi-band diplexer approach with sub-sets of imbricated passbands are detailed by means of a coupling–routing–diagram formalism. Besides, the generation of additional transmission zeros in each channelizing filter for higher-selectivity realizations by exploiting cross-coupling techniques into it is also detailed. Furthermore, for experimental demonstration purposes, a microstrip proof-of-concept prototype of second-order octo-band diplexer in the frequency range of 1.5–2.5 GHz that consists of two quad-band channelizing filters with pairs of imbricated passbands is developed and characterized.

scholarly journals Analysis on the Use of Briquettes as an Alternative to Improve the Generation of Thermal Energy in the Locality of Aripuana-Brazil

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6355
Author(s):  
Haylemar de Nazaret Cardenas-Rodriguez ◽  
Rosa Martins ◽  
Levy Ely Lacerda Oliveira ◽  
Erik Leandro Bonaldi ◽  
Frederico de Oliveira Assuncao ◽  
...  
Keyword(s):  
Raw Materials ◽  
Energy Performance ◽  
Mato Grosso ◽  
Energy Characteristics ◽  
Heating Value ◽  
Wood Residues ◽  
Lower Volume ◽  
Electricity Power ◽  
The City ◽  
And Storage

The city of Aripuana is one of the largest wood producer in the state of Mato Grosso, Brazil. Wood residues are used in the electricity generation at three thermoelectric plants in this region. However, the plants have high costs in transporting the wood residues (due to poor road conditions). Hence, this paper compares the energy performance of wood residues in natura and compacted as briquettes by calculating the heating value and determining the influence of moisture content on the energy characteristics of wood residues. The goal is to demonstrate the viability of using briquettes in order to improve thermoelectric generation. The wood residues from this region are affected by the high humidity of the biome. An alternative to improve the use of energy contained in the wood residues is to produce briquettes with lower humidity. This allows one to maintain high levels of heat energy in a lower volume, facilitating handling and storage. The results show that the use of briquettes improved the performance of thermoelectric plants, generating 1 MW of electricity power with less than 1 ton of briquettes. This contributes to the preservation of the environment, reducing operating costs, transportation and storage of the raw materials.

Research of Load Unbalance of a Two- Motor Variable Frequency Dtive for Scraper Conveyor

2021 ◽  
Vol 64 (4-5) ◽  
pp. 37-45
Author(s):  
Dmitry Shprekher ◽  
◽  
Gennady Babokin ◽  
Evgeny Kolesnikov ◽  
Dmitry Ovsyannikov ◽  
...  
Keyword(s):  
Load Balancing ◽  
Electric Motor ◽  
Frequency Converter ◽  
Common Type ◽  
Single Frequency ◽  
Variable Frequency ◽  
Electric Motors ◽  
Electric Drives ◽  
Scraper Conveyor ◽  
Simulation Results

The article analyzes the uneven loading of the scraper conveyor electric motors. The most common type of multi-motor conveyor is considered here: two-drive, with head and end drives connected through gearboxes and sprockets by an endless chain with scrapers. The simulation results are presented for three variants of com-binations of parameters of electric drives. It has been established that the use of a two-motor variable frequen-cy drive of a scraper conveyor powered by a single frequency converter inevitably entails uneven loading of the electric motors of the head and end drives. To eliminate this disadvantage, it is proposed to supply each electric motor from its own frequency converter. A system of automatic load balancing is proposed. The implementation and the result of the work of the load balancing system are carried out on a model in the Matlab / Simulink system.

Research on Accurate Modeling and Control for Pneumatic Electric Braking System of Commercial Vehicle Based on Multi-Dynamic Parameters Measurement

2020 ◽  
Author(s):  
Yongtao Zhao ◽  
Yiyong Yang ◽  
Xiuheng Wu ◽  
Xingjun Tao
Keyword(s):  
Dynamic Response ◽  
Real Time ◽  
Predictive Control ◽  
Control Algorithm ◽  
Control Algorithms ◽  
Dynamic Parameters ◽  
Braking System ◽  
Control Scheme ◽  
Braking Force ◽  
Electric Braking

Abstract Accurate pressure control and fast dynamic response are vital to the pneumatic electric braking system (PEBS) for that commercial vehicles require higher regulation precision of braking force on four wheels when braking force distribution is carried out under some conditions. Due to the lagging information acquisition, most feedback-based control algorithms are difficult to further improve the dynamic response of PEBS. Meanwhile, feedforward-based control algorithms like predictive control perform well in improving dynamic performance. but because of the large amount of computation and complexity of this kind of control algorithm, it cannot be applied in real-time on single-chip microcomputer, and it is still in the stage of theoretical research at present. To address this issue and for the sake of engineering reliability, this article presents a logic threshold control scheme combining analogous model predictive control (AMPC) and proportional control. In addition, an experimental device for real-time measuring PEBS multi-dynamic parameters is built. After correcting the key parameters, the precise model is determined and the influence of switching solenoid valve on its dynamic response characteristics is studied. For the control scheme, numerical and physical validation are executed to demonstrate the feasibility of the strategy and for the performance of the controller design. The experimental results show that the dynamic model of PEBS can accurately reflect its pressure characteristics. Furthermore, under different air source pressures, the designed controller can stably control the pressure output of PEBS and ensure that the error is within 8KPa. Compared with the traditional control algorithm, the rapidity is improved by 32.5%.

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