Russian Electrical Engineering 

About: Russian Electrical Engineering is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Voltage & Induction motor. It has an ISSN identifier of 1068-3712. Over the lifetime, 1790 publications have been published receiving 7395 citations.

An electric traction drive for electric vehicles

Abstract: Problems of expanding the range of speed regulation in electric transport vehicles by replacing gear-shift transmission with a two-channel electric drive comprising two electric motors, each coupled with its own reducing gear units possessing different gear ratios. The output shafts of these reducing gear units are coupled to one differential speed-reduction device. To solve this problem, a mathematical model of the electric-motor drive has been developed and the static characteristics of the individual motors and characteristics of the motors with their output shafts driving one differential speed-reduction device have been determined. Steady conditions of the operation of a two-channel electric drive are considered. To describe real changes in the speed variables, the electromechanical transducer is approximated in the mathematical model with nonperiodic first-order links. The functions of the controlling effects, which are formed on the basis of the criterion of fullest utilization of electric machines with respect to their electromagnetic torque in stable conditions and in transient processes, were determined. Recommendations are given on application of the proposed solution to traction mechanisms, which should meet increased requirements to acceleration of electric-motor vehicles.

An evaluation of frequency methods for creating a system to control semiconductor converters

Abstract: I explore the possibility of increasing the response speed of the semiconductor converters that operate in the pulse mode by increasing the carrier frequency or rejecting pulse-width modulation (PWM) in favor of frequency PWM. The relation between the PWM carrier frequency and the limit response speed of the current loop achievable in closed control systems using classical frequency methods for creation of linear systems has been established. A model of mathematical simulation of a semiconductor device is proposed. The model is approximated by ideal elements without considering the voltage drop on the semiconductor keys and the dead-time interval. Using the simulation model, the frequency characteristics of of the frequency converters are compared with one converter operating in the linear mode and the other in the pulse mode. The limiting value of the frequency starting from which the frequency characteristics of the linear and pulse systems diverge has been determined for different kinds of the transfer functions of the “unchangeable” part. It has been established that this frequency approaches the Nyquist frequency most closely at resonance-peak amplitude A m > 1.

An electrical feed drive-control system for a cold reducing mill

Abstract: Methods of control synthesis with the selection of parameters of the electrical-power equipment of a cold reducing mill using the example of the Chelyabinsk Pipe-Rolling Plant have been proposed. The proposed methods of a multiconnected system based on the minimum-error criterion for positioning of a movable element, and it is different in that the selection of the control structure is determined by the frequency ratio of the contour cutoff “unchangeable part” of the electric drive and electromagnetic-torque control loop. The task of control synthesis was divided into three stages. The first stage is the search for the optimal curve of movable-element variable speed based on the criterion of minimum electric losses. The second stage is parametric optimization of the electric-power-system parameters. Finally, the third stage is selection of the structure and parameters of the control-system corrective links. Control measures in systems with subordinate regulation and modal control with a change of the frequency ratio of the contour cutoff “unchangeable part” of the system and torque control were compared during research. The developed control-synthesis methods for the positioning electric drive may be recommended for any technological facilities of steel production in which an electric drive provides motion for a movable element with a high level of accuracy.

Improving the reliability of semiconductor converters for supplying electric drives of exhausters

Abstract: This article analyzes the existing methods of increasing reliability through multiple overstatement of the installed power of electric equipment according to the criterion of minimum total yearly costs. The proposed method of optimization of power circuits of semiconductor converters includes stages of choosing the configuration of power circuits on the basis of the limit of semiconductor switches and choosing the optimal number of phases and redundant units. The distinguishing characteristic of the method is the criterion used, namely, the probability of failure-free operation. This new method reduces the cost of installed power of a semiconductor converter compared to the known synthetic method on the level of total annual costs. It is shown that this method has some degree of flexibility; e.g., the development of the element base can be considered on the basis of the corresponding coefficients that depend on the operating temperature of power semiconductor valves. The proposed method can be successfully used in the design of semiconductor converters for supplying powerful electric drives, where, in the general case, the number of phases of a power circuit is not three. In this case, multiphase windings of an electric machine are connected according to a scheme with potential phase separation, which can be considered as an equivalent multiple redundancy system.

Analysis of start-retardation modes in high-power synchronous electric drives

Abstract: The article analyzes the start-retardation modes of synchronous electric drives of high-power exhausters, which are accompanied by high starting currents, not only under a direct start, but also under control of electric energy flows from a semiconductor converter. A mathematical model of electric drive is proposed and substantiated for the analysis of transition processes of ac electric drives. This model has an electromechanical converter that constitutes the links with distributed parameters. A distinctive feature of the model is refinement of the magnetization characteristic of the magnetic-circuit steel, which was carried out during full-scale measurements of the variables of the synchronous electric drive with direct start of the exhauster. To check the adequacy of the mathematical model, the results of a full-scale test were compared with the simulation results by statistical methods using Student’s criterion. The computational results using the proposed model were compared with the calculations by the classical models with lumped parameters. It has been noted that, in the overload zone (for M > 1.5 MN) the calculated values differ considerably, with this being especially evident at low speeds. The obtained results can be recommended for selection of the parameters of semiconductor converters.