Electric Drive Control System Research Articles

Control Strategy of the Electric Drive for a Switched Reluctance Motor with Improved Performance

The switched-reluctance motor due to its advantages can be used in vehicles of low and medium power, as a replacement for permanent magnet motors. However, at the moment, due to significant torque ripple, insufficient power density and driver complexity, it is not widespread. The article describes the structure of the switched-reluctance motor with a special C-shaped tooth structure of the poles of the stator and rotor located in a non-magnetic body, which has improved characteristics in comparison to the traditional structure, where the rotor and stator are completely made of soft magnetic materials. A special technique for the formation of the magnetic flux, by which a constant torque is achieved, is proposed for this switched-reluctance motor structure. The form of the stator winding current is given to ensure a given magnetic flux. Due to the high-frequency current generation, the dimensions of the motor are minimized. As a result, the basic requirements for the electric drive converter were formed. An analysis was made of popular solutions that can provide a given current shape with a steep edge and having high efficiency. As a result, the optimal structure and the algorithm for generating the current of the converter were determined. Since the engine operates at an increased frequency, a resonant converter was selected, which provides soft key switching, ensuring high efficiency. Also, to increase the torque and engine efficiency, a two-section pole structure with the same number of sections on the rotor and stator using additional windings is proposed. The proposed structure and algorithm of the motor operation implies the operation of only one pole of the stator at a time, and as a result, only one electric drive can be used for the entire motor, which will switch between the poles using two-way keys. As a result, the proposed driver consists of only four resonant converters. The results of the switched-reluctance motor electric drive control system were tested in the Matlab Simulink® environment and, as expected in theory, the total force has no ripples. As a result, the developed electric drive has a simple structure with a minimized number of converter modules and requires only four modules, regardless of the number of stator poles. Due to the high-frequency method of forming the stator magnetic flux, the dimensions of the motor are minimized. As a result of using a resonant bridge converter, the dynamic losses are minimal.

A Control System of an Electric Drive with a Synchronous Reluctance Machine with Independent Excitation

A method for adjusting frequency-regulated drives with the synchronous reluctance machine with independent excitation is proposed using the KhPT-250 cold tube reducing mill and traction drive of a Gazelle-Next electric vehicle as example; the method consists in independent adjustment of the phase currents with the subsequent identification of parameters of the control object by methods of frequency identification. It has been shown that, with independent control of the excitation currents and the anchor reaction, the cross links between phase current control loops can be neglected, which can be accounted for by the large bandwidth of the uniform pass-through frequency of the phase current control loops and the weak influence of phase windings located in the interpolar gap on the operation of the phase windings that currently located above the pole. It has been shown that when the drive operates at high speeds, a significant decrease in the proportionality coefficient between the magnitude of the electromagnetic moment and current is observed, which is explained by the finite speed of the phase current control loop. When adjusting the electric drive control system with dual-zone speed control, it has been suggested to introduce a correction for the anticipatory effect of the phase current in order to provide a constant relationship between the anchor component of phase current and the magnitude of electromagnetic moment.

Элементы искусственного интеллекта в системах управления электроприводом с нечеткой логикой

Элементы искусственного интеллекта в системах управления электроприводом с нечеткой логикой

Research of electric drive systems with real time software configurable control

Subject of Research. The paper discusses design principles of educational laboratory bench for practical research of electric drive control systems. The laboratory bench provides training opportunities for students in “Control of Electrical Drives” course and is used to increase the efficiency of material acquisition. Method. The proposed solution was based on the method of mutual loading of electric machines powered by the power converters with a common direct current link. At that, one electric machine can be used as a tested one, and the other as a load one, and vice versa. The flow of power from a machine operating in generator mode to a machine operating in motor mode was ensured, which provides an energy-saving mode of operation when power is consumed only from the network to cover losses in power converters and the machine unit. To study the various structures of control systems for direct and alternating current motors, a method for software creation with a freely configurable structure was proposed. Main Results. The paper describes laboratory stands that contain a two-machine unit, where each electric motor receives power from its power semiconductor converter controlled by a real-time microcontroller control system. The software has been implemented for the synthesis of the control researched structure using the control system settings. The system setting is performed by a number of freely configurable control elements, which are then compiled into a control algorithm for the microcontroller. To ensure the safe execution of the experiment, the control algorithm works in conjunction with the main on-line software. Thus, protection for electric motors and power converters is provided. Thanks to the built-in protection software, it has become possible to achieve reliable operation of electric drives with the power of 1.5 kW, as well as to realize characteristics close to industrial ones. The paper describes in detail the features of laboratory equipment and software for the system of an induction motor field-oriented control. This example demonstrates the setting of control systems, compiling of executable code, an experiment procedure and evaluation of results. Practical Relevance. The considered approaches to the educational equipment creation can be used in the design of similar educational equipment in related disciplines. The results are applicable for scientific and research-pedagogical staff during the course of specialist training in the field of electric drive control systems. The presented equipment has been actively used for more than 5 years and can be of practical value in the educational process.

Application Analysis of Single Chip Microcomputer Technology in Electric Drive Control System

With the continuous development of information technology, the performance of the entire electrical traditional system is gradually optimized. Among them, the single-chip technology as an important part of the electrical traditional system determines the operation quality of the entire traditional system. Based on past work experience, this paper summarizes the basic overview of single-chip technology. This paper is analyzing the application in software system, the improvement of the whole device performance algorithm, the application in the system header file, the application in the control system, the practical application. The six aspects of precautions and application examples are discussed in the application of single-chip technology in electric drive control system.

Влияние системы управления электропривода на энергоэффективность работы скважинной штанговой насосной установки

Влияние системы управления электропривода на энергоэффективность работы скважинной штанговой насосной установки

Повышение качества регулирования натяжения полосы агрегата непрерывного горячего цинкования

The paper studies a system of interconnected electric drives in the operational area of the continuous hot dip galvanizing unit located in the coating shop at PJSC Magnitogorsk Iron and Steel Works (PJSC MMK). It particularly focuses on the mechanical part with elastic elements and electric drive control systems. The paper aims at studying the existing operating modes of electric drives of the main mechanisms in the operational and output areas of the galvanizing unit; identifying ways to improve the static and dynamic performance of the interconnected electric drives system; developing an improved control system that provides for the better dynamic performance with indirect strip tension control. The authors propose a new control system for the operational area electric drives with corrective speed feedback. The dynamic characteristics of the traditional and the proposed systems were studied using a mathematical model of electric drives of the analyzed section with account to their interconnection via an elastic strip. The model accounts for eight electric drives, i.e., a hot tension station, tension stations no. 3, 4, 5, 6 and a training stand. Each electric drive is modeled with account for mecha­nical inertia and a (speed or torque) control system. The comparative analysis of tension control quality indicators for these systems proved the advantages of the developed system. The research outcomes can be used for similar units of continuous strip processing, featuring the technological line sections with a significant length of the strip between the adjacent electric drives.

POSITIONING MODES SIMULATION OF OPTIMIZED IN TIME DOMAIN SLIDING MODE CONTROL SYSTEM WHEN CHANGING THE CALCULATED VOLTAGE AMPLITUDE

Electric drives are characterized by the restriction of intermediate coordinates in transient modes. Such restrictions are implemented by a system with cascade controllers. The N-i switching method, which has a relatively simple mathematical apparatus, provides optimization for the speed of cascade sliding mode control systems. In this work, a comparative study of the typical operating modes of the control system for the position of the output shaft of the electric drive is carried out. At the same time, the parameters of the optimal regulators were varied based on a change in the calculated voltage value of the power converter. Performance optimization is based on the calculated trajectories of the idealized control object. The study of the positional electric drive control system revealed deviations of the transition trajectory from the calculated one. The reason for this effect is the influence of the internal feedback of the electromechanical system, leading to the early entry of the regulators into the sliding mode. The obtained families of transient characteristics make it possible to construct empirical dependences of the duration of regulation on the relative value of the calculated jerk of the output shaft for all typical positioning modes. Such dependencies have pronounced extremes, which makes it possible to tune the drive to near optimal speed by preventing premature entry of the regulators into the sliding mode. The results of the research open the prospect on practical realization of adaptive algorithms for the synthesis of cascade sliding mode control systems based on the N-i switching method.

Electric drive control system of the paper-making machine

Here are presented the synthesis of paper-making machine electric drives control systems. Quality indicators of paper and cardboard are directly related to the accuracy characteristics of the electric drives of both machine wires in conditions of unpredictable changes in loads on their shafts. It is shown that to solve the problem of stabilization of wires velocities and their ratio it is advisable to implement the principle of servo control. It is proposed to use the lower wire speed stabilization subsystem as the leading one, and the upper wire speed servo subsystem with the stabilization of the zero deviation of the integral from difference of electric drives speed. Presents the results of a synthesis and analysis of two-dimensional servo system finite electric drives control in conception of the modern vector-matrix control theory. A discrete-continuous mathematical model of the electromechanical system is obtained. To ensure the quality of speed control, discrete finite state regulators are used. As a result of the synthesis, expressions for the implementation of a discrete control device are obtained. In simulation, the reactions of the drives to the increment of the speed and to the increments of the loads on the drive shafts are obtained. The simulation results showed the effectiveness of the proposed principles of electric drive control. The electromechanical system demonstrates the properties of astatic control and reduces the deviation of velocities in steady-state modes to zero. The solution to the problem of reducing the mutual influence of electric actuators for the stabilization of the velocities of the machine wire and maintaining them in the specified ratios will reduce to a minimum the displacement of the paper layers formed on both machine wires. The practical application of the proposed electric drive control system in production contributes to improving the quality of products manufactured on a paper machine.

Algorithmic structure of control system of mine winder electric drive with a doubly-fed motor

Usage of doubly-fed electric machine is a promising means to modernize asynchronous electric drives of mine winders based on wound rotor induction motor. To ensure a wide range of speed regulation, typical of mine widers, while maintaining the critical torque of the machine and its overload capacity, it is necessary to control amplitude, frequency and phase shift of the auxiliary voltage on the rotor. Since the frequency and phase shift determine the additional voltage argument, and the amplitude determines its modulus, then the speed control by changing the module and the argument is a non-trivial task requiring a special structure of control system of mine winder electric drive, as well as special regulators, and the system is non-linear. This article discusses the construction of a functional structural diagram of electric drive control system based on a doubly-fed motor, which allows the indicated features of controlling the speed of a doubly-fed machine to be taken into account by changing the parameters of the auxiliary voltage on the rotor.

Automated control system of electric drive with doubly fed induction motor

The article describes the development of an automated control system for electric drives, which includes a doubly fed induction motor, a digital position sensor and National Instruments equipment, represented by the PXI modular platform and LabVIEW software. The features of the interaction of software and hardware of the electric drive control system are considered. During operation, the system uses various levels of interaction of virtual instruments within one project. Thus, the use of virtual instruments of the project occurs at the level of the personal computer of the workplace, controller and the module with a programmable logic integrated circuit. The method of using a dynamically connected library for the calculation of parameters and state variables of the electric drive in real time is presented.

An Automatic Electromechanical Drive for Carriage Doors

This paper considers the application of a carriage door electric drive based on sealed electromechanical ac converters with a linearly moving actuator of the traction gear for protection against unauthorized access to the carriage. Not only does the drive deliver high specific performance, but it also makes possible controlled access to the carriage. It is shown that the sealed electromechanical converters used for these purposes make transport systems more reliable and ergonomic. This article also presents the results of modeling the electric drive control system by fuzzy techniques that make the control process more efficient and improve the resistance to operator-assigned factors.

Система управления электроприводом тянущих роликов машины непрерывного литья заготовок при деформации бочек роликов

Система управления электроприводом тянущих роликов машины непрерывного литья заготовок при деформации бочек роликов

Improving the dynamics of a synchronous in-phase electric drive in transient modes of synchronization, phasing and control in response of reference signal changes

Synchronous in-phase electric drive is widely used in thermal-imaging and laser scanning systems due to their high accuracy and dynamic characteristics in a wide range of angular velocity control. The purpose of the article is to develop ways to control a synchronous-in-phase electric drive in the modes of synchronization, phasing and control in response of reference signal changes, allowing to improve the dynamic performance of the electric drive and reduce information loss in the scanning system. The method of electric drive phasing that is quasi-optimal in speed has been improved. Recommendations on the organization of transient processes with an abrupt change in the reference signal are formulated. For use in the electric drive control system, a circuit implementation of an impulse frequency-phase discriminator with an extended linear zone in the phase comparison mode has been proposed, it allows to improve the dynamic performance of the electric drive in the modes of synchronization, phasing and control in response of reference signal changes.

Synthesis of energy-efficient agriculture electric drives control system

In this paper the capabilities of the agriculture electric drive with rectangular shape of the phase current were analyzed, the level of pulsations of the electromagnetic torque in synchronous reluctance electric drives was found, the synthesis of the electric drive control system was considered, the characteristics of the electric drive under different control laws were compared. It is found that the use of high-speed current circuits (cutoff frequency = > 200 rad/s) can significantly suppress the level of pulsations of the electromagnetic torque. It is shown that the use of flexible positive current feedback in switching phase currents can be considered as an additional opportunity to improve the performance of the current control circuit, as well as in conjunction with the previous method for suppressing torque pulsations in both static and dynamic modes.

A Traction Electric Drive of for a Gazelle-Next Electric Vehicle

The rated engine speed and torque of an engine are calculated against the criterion of minimum losses and on the basis of the load graph of the traction electric drive of the Gazelle-Next electric vehicle (EV). It is shown that this approach allows making the system more efficient by around 10%. A mathematical model of the system is developed, where the traction torque indirect adjustment loop is approximated by aperiodic first-order links one of which takes into account uncompensated electromagnetic response delays of phase circuits, whereas the other approximately takes into account the restricted response time of the microprocessor control system. The suggested procedure of synthesizing the traction electric drive control system allows reducing the self-oscillations of the object operated in the zone of torque and speed overloads. It is found that the best adjustment figures for traction mechanisms used in complex operating conditions are reached in the structure with an internal corrective loop against the active capacity coordinate. This is due to the possibility of directly measuring the coordinates of phase current and voltage, which ensures the zero lag of the feedback line. The system adjustment quality was evaluated for the “Traction effort-output speed” line, which involved modeling glare ice as the most complicated running mode for the electric drive, when the traction drive changes from peak to zero almost according to the step law. In this case, the speed coordinate was readjusted by no more than 8%.

Идентификация математической модели электромеханической системы

The article considers application of real interpolation method for identifying a linear dynamic system (specifically, an electromechanical system) which allows the system transfer function to be identified from the system unsteady motion transients. In so doing, the test signals presented in the form of readout arrays in the time domain are approximated, and the transfer function coefficients are calculated at real points (interpolation nodes). The identification method mathematical description is presented which consists in calculating the test signals convolution and weight functions and involves solution of a system of linear algebraic equations. The time transformation of test signals is used to bring their duration to the normalized time. By using this approach, the most significant coefficients of the identified transfer function that have a significant effect on the system dynamic behavior are determined, as well as the least significant coefficients which can be excluded from the mathematical model for simplifying it. The requirements for test signals, for the quantization of representing them in the time domain and for the interpolation nodes are specified. A software for implementing the identification method has been developed in the Matlab system environment which can be used in research applications on a personal computer or in microprocessor control systems. The possibility of implementing the real interpolation method by means of microprocessor software and hardware facilities is pointed out. To this end, an experimental electric drive control system has been develope, which involves means for generating reference signals, for measuring test signals and for carrying out computations according to the identification method. The software for performing identification tasks has been developed using model-oriented programming techniques and integrated in the electric drive control system software. The study activities included model and full-scale experiments on identifying the electromechanical system elements.

Software and hardware solution for digital signal processing algorithms testing

The article describes the microprocessor system for various digital signal processing algorithms testing. The development of electric drive control systems is carried out with the usage of modeling systems such as, MATLAB/Simulink. Modern digital control systems are based on specialized digital signal microcontrollers. The present market offers evaluation boards, for example STM32F4DISCOVERY, which enables to connect a microcontroller to a personal computer. It makes possible to use the microcontroller as a part of the mathematical model of the control system. However, the designing of the control system simulation model and the program for the microprocessor is carried out in different programming environments. Thus, the software and hardware solution for testing programs for the microprocessor, which is a part of the control system, is relevant. This article deals with the designing of the modeling method in which the prototype program for the microprocessor is debugged as a part of the electric drive control system simulation model.

Modeling of Sensorless Determination of the Resistance and Temperature of the Stator and Rotor Windings of an Asynchronous Motor

A brief survey of the existing sensorless methods of determination of the temperature of the stator and rotor windings of the asynchronous motors (AMs) is given. It is stated that one of such methods is indirect determination of the temperature by measuring the active resistance of the AM windings. on the AM equivalent circuit, the possibility of determining the resistance by introducing the additional components of the stator winding voltage is theoretically justified. The conditions for the correct determination of the parameters when introducing the ac voltage component are stated. The features of the AM mathematical model and method of modeling of determination of the winding resistance in the Matlab packet are studied. The results of modeling determination of the stator winding resistance by introducing the direct voltage component and rotor winding resistance by introducing direct and high-frequency voltage components are presented. The influence of the introduced voltages on the electromechanical coordinates of the electric drive is analyzed. Proposals on selection of the frequency of the ac voltage component are given. An estimation of feasibility of the suggested method in modern electric drive control systems is made.

Equivalent model of a dually-fed machine for electric drive control systems

The article shows that the mathematical model of a dually-fed machine is complicated because of the presence of a controlled voltage source in the rotor circuit. As a method of obtaining a mathematical model, the method of a generalized two-phase electric machine is applied and a rotating orthogonal coordinate system is chosen that is associated with the representing vector of a stator current. In the chosen coordinate system in the operator form the differential equations of electric equilibrium for the windings of the generalized machine (the Kirchhoff equation) are written together with the expression for the moment, which determines the electromechanical energy transformation in the machine. Equations are transformed so that they connect the currents of the windings, that determine the moment of the machine, and the voltages on these windings. The structural diagram of the machine is assigned to the written equations. Based on the written equations and accepted assumptions, expressions were obtained for the balancing the EMF of windings, and on the basis of these expressions an equivalent mathematical model of a dually-fed machine is proposed, convenient for use in electric drive control systems.