Comparison of Energy Indicators of the Electric Lift Drive of the Ekg-5 Excavator with Different Power Converters

Author(s):  
Eduard Grekov ◽  
◽  
Alexei Bezgin ◽  
Viktor Sorokin ◽  
Ildar Yamansarin ◽  
...  

The energy indicators of the EKG-5 excavator lifting electric drive with thyristor power circuits have been determined according to the systems thyristor direct frequency converter - two-phase asynchronous electric motor, converter-DC motor and direct frequency converter - three-phase asynchronous electric motor. Losses in electric motors and converters have been determined, taking into account the specifics of their joint work in theefficiency for the excavation cycle were determined based on the results of calculating the simulation model, the initial data for which were the parameters of the excavation cycle of the lift drive of a real excavator. Distortion coefficients of the mains current were determined for two cases: during digging and during accelerated lowering of an empty bucket. For comparison, the energy indicators of the selected electric drives with a filter-compensating device were calculated. The analysis of energy indicators is made.

Vestnik MGTU ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 364-375
Author(s):  
A. N. Tsvetkov ◽  
V. Yu. Kornilov ◽  
A. R. Safin ◽  
N. E. Kuvshinov ◽  
T. I. Petrov ◽  
...  

In the modern oil industry, the vast majority of oil production units are represented by sucker rod pumping units, driven mainly by asynchronous electric motors without using any monitoring, control and regulation means. Studies carried out on such installations show their low energy efficiency and reliability. Therefore, the issue of developing complex electric drives of a new generation based on the use of synchronous valve electric motors is relevant allowing to significantly increase the energy efficiency and reliability of both individual installations and to ensure the creation of "smart" oil field control systems. The paper discusses new technical solutions of the experimental stand which makes it possible to study the energy characteristics of electric drives based on asynchronous and synchronous valve electric motors, as well as allowing to create conditions as close as possible to real field conditions with imitation of the operation of an oil pumping unit of a sucker rod pumping unit. In modern test equipment systems, devices are often used to create a mechanical load on the shaft of the electric motor under study. The system proposed and implemented as such a device is "a frequency converter - load asynchronous electric motor", which has been tested on a stand and has proven to be the best in comparison with traditional circuits using DC motors. But using of a load asynchronous electric motor as part of the test stand has revealed a number of disadvantages: overheating of the electric motor operating in the opposing mode, low accuracy of creating the load torque and the speed of the system's response. The problem of overheating of the load electric motor has been solved by transferring the frequency converter to the direct torque control mode, while a significant decrease in the motor current and stabilization of the temperature regime have been detected. The low accuracy and response speed of the system have been increased by introducing feedback and a PID controller into the stand control system.


Author(s):  
Dmitry Shprekher ◽  
◽  
Gennady Babokin ◽  
Evgeny Kolesnikov ◽  
Dmitry Ovsyannikov ◽  
...  

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.


Vestnik IGEU ◽  
2019 ◽  
pp. 49-61 ◽  
Author(s):  
V.N. Meshcheryakov ◽  
A.S. Belousov

High overload capacity and ability to control speed in a wide range are important requirements for modern electric drives. Introduction of a low-power adjustable two-phase electric drive with these properties into me-chanical devices is limited by the frequency converter function to convert a three-phase network into a two-phase one when the unit power of such mechanisms increases. Previous studies have shown that it is possible to use a standard frequency converter with a three-phase bridge voltage inverter applying a new control algorithm based on space-vector PWM. When PWM is used, the switching frequency of the key inverter elements remains quite high, strictly specified, non-amenable to reduction without degrading the harmonic composition. The goal of this work is to develop an algorithm for two-phase electric drive control that would reduce the number of switching operations of the switch elements of a three-phase inverter with-out increasing the deviations of the instantaneous values of the phase currents from the reference sine curve. The study employed provisions of the theory of automatic control, the theory of electric drive and methods of mathematical modeling. The simulation object was the control system of a two-phase motor; the elements of the Matlab Simulink software package were used. An algorithm has been proposed for operating a three-phase inverter of a two-phase electric drive system. The difference of the algorithm from the well-known control system of a standard bridge inverter with space vector PWM consists in using phase current control relays and dividing the period of sinusoidal phase currents into four sections ensuring a decrease in the number of switching operations of the inverter switch elements when the maximum instantaneous deviations of current values from a sinusoidal reference are equal, the starting torque of the motor is stabilized and the speed control is smooth. The results show that with an equal maximum deviation of the instantaneous current values from a given sinusoidal value, the number of switching operations of the inverter switch elements in the proposed system is smaller than in the known analogues. The electric drive system ensures the start of a two-phase motor with stabilization of the starting torque under increased load. The considered system of variable frequency control with current control relays can be used for two-phase electric drives of mechanical devices and household electric appliances and is promising as a substitute for less cost-effective single-phase and capacitor motors.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1738
Author(s):  
Vanessa Neves Höpner ◽  
Volmir Eugênio Wilhelm

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.


2020 ◽  
Vol 11 ◽  
pp. 11-17
Author(s):  
Gabriel Nicolae Popa ◽  
Corina Maria Diniș

Low-voltage three-phase induction motors are most often used in industrial electric drives. Electric motors must be protected by electric and/or electronic devices against: short-circuit, overloads, asymmetrical currents, two-phase voltage operation, under-voltage, and over-temperature. To design the electronic protection currents, voltages and temperature must be measured to determine whether they fall within normal limits. The electronic protection was design into low capacity PLC. The paper presents the designs and analysis of complex electronic protection for general purpose low-voltage three-phase induction motors. The electronic protection has Hall transducers and conversion electronic devices for AC currents to DC voltages, AC voltages to DC voltage, temperature to DC voltage, a low capacity PLC, switches, motor’s power contactors, and signalling lamps has been developed. Experiments with complex electronic protection, for different faults are presented. The proposed protection has the advantages of incorporating all usual protections future for the low-voltage three-phase induction motors.


2021 ◽  
Vol 2 (3) ◽  
pp. 48-56
Author(s):  
Margarita M. Blagoveshchenskaya ◽  
Mikhail V. Veselov

Frequency converters of asynchronous three-phase AC motors are widely used in industry, including food production. A thorough understanding of the technical capabilities of frequency converters contributes to their efficient use. This article discusses a technical comparison of two frequency converters of three-phase electric motors of the Russian company "OWEN" and the Danish company "DANFOSS" according to the criterion of the quality of regulation of the technological parameter. For comparison, a test bench was created, in which the devices were tested in turn, under the same conditions. During the preparation and implementation of testing, it turned out that the hardware capabilities of frequency converters for their use in regulating technological parameters are the same, and the parametric capabilities are different. The frequency converter of the "OWEN" company is equipped with a PI controller, and the frequency converter from "DANFOSS" is equipped with a PID controller. As the results of testing the devices show, despite 


2020 ◽  
Vol 241 ◽  
pp. 37
Author(s):  
A. Vorontsov ◽  
V. Glushakov ◽  
M. Pronin ◽  
Yu. Sychev

The structures of systems with high-voltage cascade frequency converters containing multi-winding transformers and low-voltage low-power converters connected in series at each output phase of the load are considered. Low-voltage blocks contain three-phase diode or active rectifiers, DC capacitor filters, single-phase stand-alone voltage inverters and block disconnecting devices in partial modes (in case of failure when part of the blocks are disconnected). The possibilities of operation of cascade converters are determined, equations for correcting tasks to units in partial modes are given, tables of correction of tasks with estimates of achievable load characteristics are proposed. The results of experiments on the model of a powerful installation with a cascade frequency converter are presented, confirming the possibility of ensuring the symmetry of the load currents when disconnecting part of the blocks and the asymmetry of the circuit.  


Author(s):  
Bogdan Y. Vasilev

<p>In the paper describes the AC electric drive, which consists of the induction motor and the semiconductor converter. Structure of the frequency converter, which includes a three-phase bridge inverter on based fully controlled transistors, is considered. The algorithm of pulse width modulation, which used in the majority of the electric drives, is discussed. The characteristics and shortcomings of the algorithm is shows. Algorithmically methods to improve the efficiency of the inverter – promodulation control signal. The efficiency of this method in different variations is given. The level electromagnetic compatibility inverter and efficiency various control algorithms are analyzed. The conclusions about feasibility of using the method promodulation.</p>


Sign in / Sign up

Export Citation Format

Share Document