Field Regulated Reluctance Machine Research Articles

ВЫБОР ПАРАМЕТРОВ СИЛОВОГО ЭЛЕКТРООБОРУДОВАНИЯ СТАНОВ ХОЛОДНОЙ ПРОКАТКИ ТРУБ

Parameters identification of power electrical equipment for technological objects with complex and non-standard kinemat-ics of working bodies is considered. Operation features analysis for a cold-rolling pipe mill is carried out and the relevance of the design problem of electric drive system is substantiated. The advantages of a field regulated reluctance machine are substantiated considering the peculiarities of the technological operations and equipment. Motor electromagnetic torque pa-rameter is used as criteria for geometry optimization problem. The mechanical stresses calculation of the rotor proposed design for given speeds and loads is performed. The influence of a "jumper" in the radial direction on the strength of the machine rotating parts is shown. The multi criteria optimization task for the configuration of power circuits is carried out according to capital costs and reliability. The effectiveness of a six-phase three-level electrical converter is substantiated. The operation speed of the electric drive of the auxiliary mechanism is increased by almost three times, and the perfor-mance of cold-rolling pipe mill is improved by 10-15%. Power circuits configuration for multilevel electric converter en-sures a reduction of losses by 1%.

ОПТИМИЗАЦИЯ НОВЫХ ТИПОВ ЭЛЕКТРОМЕХАНИЧЕСКИХ ПРЕОБРАЗОВАТЕЛЕЙ ДЛЯ МЕХАНИЗМОВ С ВЕНТИЛЯТОРНЫМ ХАРАКТЕРОМ НАГРУЗКИ

Abstract. The article considers the main requirements for pumping stations, in particular, for methods of regula¬ting the water supply at the first lift pump unit. A description of the pumping unit and equipment is provided. The artic¬le pro-vides a comparison of the types of the main drive units of pumping stations. It also provides a rationale for the choice of electric drive system between classical asynchronous and synchronous electric drives, as well as a system with a field regulated reluctance machine (FRRM) with a comparison of energy indicators. A description and substantia-tion of the control system work are also given. The articles provide the technical characteristics of the motor parameters and the daily flow rate of the station fluid. The optimal method for regulating the power supply system was chosen based on research. A mathematical model of the device which implements the chosen control method is presented. The results of mathematical modeling are presented in the graphs. A graph of the transient process is given in the case of changing speeds depending on the required fluid supply. Conclusions about the efficiency of the system are drawn and further action plans are outlined.

Высокоэффективный электропривод с системой технического зрения для тягового применения в тяжелых гусеничных машинах

A new type of electric motor as a traction drive DET400 based on a field regulated reluctance machine (FRRM) provides high energy efficiency and high specific torque. A comparison is made between FRRM and various types of traction electric drives. The issues of designing the FRRM are considered, the geometric parameters of the electric machine are optimized to achieve the maximum specific indicators. To expand the functionality and ensure operational safety, it is proposed to introduce computer vision into the electronic control system. As a result, the FRRM is designed for traction applications based on the real requirements of a Russian-made crawler tractor.

Differential Electric Drive for Starter-Generator of the Medium-Powered Industrial Vehilces

The requirements for electrical components of medium-power vehicles are considered. The parameters of starters and generators used on medium-power vehicles are given. Possible variants of differential electric drives are presented. The options for the implementation of a starter-generator based on a differential electric drive are presented. The usage of a planetary mechanism with control elements for changing kinematic circuits in a differential electric drive has been substantiated. The kinematic switching circuits providing the main op-erating modes of the starter-generator are considered. The advantages of a field regulated reluctance machine as a differential electric drive are given. A mathematical description of the planetary gear is given. The transfer functions of the elements of the differential electric drive are shown. A block diagram of a differential electric drive of a starter-generator based on a field regulated reluctance machine excitation has been developed. The results of the analysis of the frequency characteristics of the contours of the armature current, excitation current, torque and speed, showing the efficiency and applicability of the mathematical model, are presented

Synchronous generators for traction mechanisms

This article shows the principle of operation, experimental characteristics, comparison with other types of generators, functional diagrams of an electric generator set based on a field regulated reluctance machine. Attention is drawn to the high specific performance and favorable performance characteristics of these power generating sets. The simplicity of the design ensures high manufacturability of the electric machine, the non-contact design in combination with a “cold” winding-free rotor increases the reliability of the bearings and the entire machine, the ability to make the rotor massive (the rotor poles and the shaft are from one solid billet) significantly increase it strength and lateral stiffness. Also it allows obtaining high angular velocities and large moment overloads. Small control powers along the excitation circuit with a sufficiently high speed of this channel contribute to the achievement of high accuracy of maintaining a given voltage at favorable mass and dimensional parameters of the electric power plant.

Influence of losses in steel on the specific values of field regulated reluctance machines and traction electric drive control system

The article considers the influence of losses in steel of Field Regulated Reluctance Machine (FRRM) on its specific values and the electric drive control system. Two methods of their determination are analyzed: analytical and field. The second method is preferable, since it requires less information about the properties of materials with the same accuracy in determining losses. It is shown that losses in steel shift the optimal control angle of the stator current vector towards the q-axis of the electric machine. The angle offset when the load is increased to three times is 5 electrical degrees. It is shown that when the load current increases, the losses in steel to eddy currents and hysteresis are equally dependent on induction. With three times the load, losses increase by 60%. As the speed increases, the eddy current losses from the current increase squared, and the hysteresis losses are almost linear. This indicates a different degree of dependence of the loss components on the speed. Regression dependences of losses on the load current and speed of FRRM are given.

Electric drive of the generator of the diesel-electric tractor DET-250M2 on the basis of a Field Regulated Reluctance Machine

The diesel electric tractor DET-250M2 was the first tractor in the USSR with an all-electric transmission. This tractor usually works in agriculture as a cultivator and a bulldozer. However, it is often used in the railway sector, in industry, in large construction projects. Since the tractor’s electrical installation developed in the 1950s on the basis of DC collector machines is now obsolete, difficult to maintain, it was decided to upgrade the traction electric drive. The article presents the calculations of an electric machine: optimization of the rotor geometry, selection of the optimal ratio of the pole and interpolar gap, selection of the optimal number of poles of the machine, selection of the current shape, type of rotor. As an electric machine, a FRRM, which characterized by high overload capacity, a wide range of work in terms of torque and speed, was selected.

Перспективы развития стартер-генераторов для промышленных транспортных средств

The paper considers the requirements for and operation features of the vehicles main electrical elements. It presents the technical and operational characteristics of the storage battery, starter and generator along with the analysis of the current starter-generators state, their advantages and disadvantages in relation to medium-power industrial vehicles. The results obtained allow determining the features and assessing the possibility of implementing a starter generator. It is shown that an attempt to create an electrical complex combining the functions of both a starter and a generator in modern medium-power vehicles (industrial tractors, all-terrain vehicles, etc.), taking into account the capabilities of modern electrical equipment, is hardly rational an complex. The solution could be found within the framework of multiply connected electric drive systems, in particular, based on a differential electric drive using planetary mechanical gears and field regulated reluctance machine. The paper also describes the main advantages and features of the operation of planetary mechanisms ed. A brief description and justification for the choice of a field regulated reluctance machine from the standpoint of the implementation of a starter-generator for industrial vehicles of medium power is given.

Dynamic Behavior of Superconductor-Permanent Magnet Levitation With Halbach Arrays for Flywheel Design and Control

Our research goal is to construct a general predictive model for the design and control of a flywheel energy storage system (FESS) that utilizes a superconductor-permanent magnetic levitation bearing. The FESS machine design is a hubless field-regulated reluctance machine for which the rotor of the machine is also the rotating mass for the flywheel. Reported are the results of several experiments that show the oscillatory reactions of the levitated systems. For these experiments, the levitation height and the amount of flux penetrating the superconductor is controlled by adding mass to the levitated Halbach array and by the initial cooling conditions. A small impulsive force is delivered to the levitated array, which is then allowed to freely oscillate until it has completely decayed. From this we can find an effective spring constant and damping coefficient for the levitated system as a function of the magnetic field densities and levitation height. The goal of the experiments reported is to understand the dynamic behaviors of a levitation system and incorporate those properties into the control model for the flywheel. Initial experiments have demonstrated near critically damped harmonic behavior when a magnet array levitated by a superconductor is delivered an impulsive force. Using the data from our experiments we aim to gain knowledge of the underlying physics of the forces of interaction and to create a predictive macroscopic model based on magnetic array and YBCO properties. We compare our measured results to those obtained by using the advanced image mirror method and finite element magnetic modeling.

Electromagnetic processes during phase commutation in field regulated reluctance machine

The processes of currents switching in stator windings have been explained by the existence of the electromagnetic torque ripples in the electric drive with the field-regulated reluctance machine. The maximum value of ripples in the open loop control system for the six-phase machine can reach 20 percent from the developed electromagnetic torque. This method allows one to make calculation of ripple spike towards average torque developed by the electromotor for the different number of phases. Application of a trapezoidal form of current at six phases became the solution. In case of a less number of phases than six, a ripple spike considerably increases, which is inadmissible. On the other hand, increasing the number of phases tends to the increase of the semiconductor inverter external dimensions based on the inconspicuous decreasing of a ripple spike. The creation and usage of high-speed control loops of current (HCLC) have been recommended for a reduction of the electromagnetic torque’s ripple level, as well as the appliance of positive current feedback in switching phase currents. This decision allowed one to receive a mean value of the torque more than 10%, compared to system without change, to reduce greatly ripple spike of the electromagnetic torque. The possibility of the electric drive effective operation with FRRM in emergency operation has been shown.

EFFECTIVE CONTROL OF FIELD REGULATED RELUCTANCE MACHINE

The electrical drive based on field regulated reluctance machine is a good alternative to the induction drive because of various advantages related to energy efficiency. At the same time this type of drive is sensitive to coordinate and parametric disturbances which may affect energy efficiency and quality of control in various technological processes. This paper is to propose the method of development of control laws based on an idea of the reversibility of the Lyapunov direct method for the stability anal-ysis, and using the instantaneous value of energy as the predetermined Lyapunov function. This will ensure effective operation with a lesser sensitivity to variations of the motor’s parameters, as well as the simplicity of realization of control system.

Energy Saving in Pilger Mill Electric Drives Complete Solution

This paper considers issues related to increasing energy efficiency in electric drives of pilger rolling mills, presenting kinematics of such mills, provides justification for the general load chart, presents the detailed review of reference materials on technical energy saving solutions, and suggests a math model of an electric drive with a field regulated reluctance machine. The paper suggests key methods of saving energy in electric drives of pilger mills, namely: kinematic scheme improvement; main energy drainers and ways of energy loss reduction in electric drives with direct- and alternate-current motors, energy-saving electric drive control profiles. The article compares energy-saving resources in electric drives with various-type motors (direct-current motors, synchronous motors, and field regulated reluctance machine), clarifies the scheme of energy-saving resource implementation, provides the qualitative evaluation of electric drive control method efficiency. The accent is made on high energy efficiency of the proportionate control of armature and excitation circuits and across the range of torque in electric drives of abruptly-variable-load mills. The highest economic effect is reached in the electric drive with a field regulated reluctance machine – by means of implementing the energy-efficient electromechanical converter and applying energy-saving control profiles.

Ways to decrease losses in electric drives and improvement of electrical safety during their service

A list of recommendations to increase the energy efficiency of an electric drive by decreasing the total losses has been given. Three ways in which an energy-saving drive can be developed have been differentiated. The first approach is improvement of conventional solutions. This can be achieved by means of using new high-quality active materials in electric machines and by optimization of their power circuits. The second approach is a systematic approach to designing and taking into account the combined work of all the components of an electric drive. In this case, improvement entails development of new types of electric drives, such as switched reluctance drives, electric drives with a field-regulated reluctance machine, and others. New solutions actively use the advantages of control and power electronics. The third approach provides improvement of both the existing solutions and taking into account the combined work of a semiconductor converter and motor. Using the example of an electric drive with a field-regulated reluctance machine, calculations of total losses have been carried out and ways to decrease losses by means of choosing efficient control laws for stator currents and power transfer circuits have been demonstrated. Recommendations that allow improvement of the electrical safety of technical personnel who service electrical systems have also been suggested.

Calculations of the losses and thermal operation conditions for controlled alternating-current drives

A survey of methods of calculating losses has been proposed for a class of controlled ac drivers that work under extreme conditions with arbitrary control laws of currents and configurations of magnetic systems for electrical machines. It is shown that the existing methods have low calculation accuracy for the considered class of electric drivers (error up to 30%). The results of calculations by the finite-element method and the experimental data of simulations of thermal conditions and losses using 3D models, in which an electromechanical converter is regarded as a system with distributed parameters, have been considered; moreover, the parallel calculating algorithms have been used. For example, the calculations of losses in the 3D models of a field-regulated reluctance machine have shown that the discrepancy with the experimental data is not higher than 2%. Note that the main share of losses in steel is eddy currents. The results of calculations by numerical methods using 3D models allow one to determine the losses in controlled ac drivers for nonsinusoidal control laws of phase current of the stators with complex configurations of the magnet system of the electromechanical converter. For the considered class of electric drivers, the largest share of losses (from 60 to 80%) is eddycurrent losses.

Оптимизация функции управляющего воздействия для электропривода с синхронной реактивной машиной с независимым управлением по каналу возбуждения

The article considers the issues of control action optimization for electric drive with field regulated reluctance machine (FRRM). It defines the aim of optimization of stator’s space magnetomotive force form for various power supplies of windings with due regard to the accepted limits. The paper also provides the coupling equations. The optimum ratio considered can provide an initial evaluation of taken decisions, which significantly reduces time expenditures.

Повышение надежности полупроводниковых преобразователей и электроприводов объектов кислородно-конверторного производства

The paper deals with ways to improve reliability of semiconductor converters and electric drives of the oxygen-steelmaking facilities. It provides the dependences of reliability of the semiconductor converter – electric motor system on the power margin. It is proved that redundancy of the semiconductor converter in the synchronous reactive drive with the pulse-vector control significantly improves reliability of the system. The authors propose a mathematical model of pulse-vector control of field-regulated reluctance machine. The results of mathematical modeling the synchronous reactive drive with pulse-vector control are represented. They confirm the dependence of specific indicators of the electric drive electric on the number of phases.

Fundamental principles of the theory and practice of electric drives with a field-regulated reluctance machine

Special features of electric drives based on a field-regulated reluctance machine (FRRM) supplying high power and regulating characteristics to an electric drive are shown: the feasibility of separate and independent control of the excitation and armature fields, multiphase, waiving schemes of three-phase power circuits, and possibility of the sinusoidal current form. It is shown that independent control of the excitation and armature fields expands the range of options for solving the problem of multicriterion optimization of an electric drive with an FRRM. Calculations show that it is possible to improve the specific values by 30–40% in an electric drive with an ideal transformer due to redistribution of the active materials in the low power electrical machines, but in mediumand high-power electric drives this effect is not so great and does not exceed 10%. Attention is paid to the fact that there are no limitations as concerns commutation conditions in an electric drive with an FRRM, which allows the magnetic flow to be increased during overloading and, therefore, the short-term electromagnetic torque to be increased by from four to eight times as compared to the rated value.

Improving the energy efficiency of electric drives of reciprocating rolling mills

Components of power losses in electric drives of reciprocating rolling mills with an extremely irregular load diagram are considered. Energy efficiency is increased in the electric drive of reciprocating rolling blocks by improving electric drive components, methods, and control systems. It is confirmed that there is a high level of efficiency of the proportional control of the armature and excitation currents in the low loading area. The capabilities of both traditional systems of slave regulation and fundamentally new systems of the ac electric drive are analyzed. The nature of the benefits related to use of an electric drive with a field-regulated reluctance machine is explained—use of the whole of the armature winding coils during creation of electromagnetic torque and lack of a number of nodes with large current (compensating winding, auxiliary pole and excitation winding).

Compensation for the radial forces in an electric motor drive with a field-regulated reluctance machine

Ways to reduce radial loads on the bearings of electric machines with an electric traction drive are considered. An idea of compensation for radial loads is proposed, and a mathematical model of the electric motor drive with the controlled radial forces in the vertical direction is developed on the basis of a field-regulated reluctance machine. The model takes into account the influence of the vertical forces that are generated by various machine windings and wear in the mechanical part of the electric motor. Additional winding is used to appropriately assess the influence of the radial force. The maximum vertical force acting on the machine is calculated from the obtained waveforms. This fact allowed us to identify the future direction of research. Methods of mathematical modeling construct the dependence of the vertical force from the currents flowing in the windings of the electric machine. The minimum force is created when the field current changes, and the maximum force is created when the armature circuit current is varied. This indicates that the winding provides maximum compensation for the radial force.

A traction electric drive for electric cars

It is advisable to use a controlled electric drive in electric drives of electric off-road vehicles due to its significant multiplicity of the supported torque (5: 1 and higher) in a low-power mode. Such overloads can be achieved, for example, in electric drives with a field-regulated reluctance machine, not only because of the capacity of the electric machines, but also due to the choice of the drive control system. Analysis of requirements for the electric drive of an electric vehicle is performed, and the influence of the control method on the specific parameters is considered. Analysis of the number of independent control actions in synchronous reluctance electric drives is provided. The possibility of increasing the overload multiplicity of the torque by abandoning the vector control in favor of structures similar to dc drive systems is shown.