Optimization Of Automatic Control System Research Articles

Method of reliability control of thermoelectric systems to ensure thermal regimes

The paper presents the results of research of controllability of the thermoelectric system for ensuring thermal modes of electronic equipment, including a regulator, a cooler, and a component of excess heat removal to the environment. It is shown that for the use of methods of optimization of automatic control systems it is necessary to study the transfer and dynamic characteristics of the object - thermoelectric cooling device with one input and one output. The mathematical model of the thermoelectric cooler of the system of providing thermal modes of a given design is presented, which takes into account the influence of the conditions of interaction of the heat sink with the medium on the main significant parameters, reliability indicators, dynamic and energy characteristics of the single stage cooler. The model is created for the operating range of cooling, level of thermal load, geometry of thermocouple branches, different temperature of the medium, for the characteristic thermal regime of maximum cooling capacity. The results of calculations of the main significant parameters, reliability indicators, dynamic and energy characteristics of the cooler for different medium temperature in the operating temperature range and variation of conditions of heat exchange of the heat sink with the medium are given. It is shown that as the intensity of heat exchange of the heat sink with the medium increases, the temperature difference between the heat sink and the medium decreases. This makes it possible to significantly reduce the relative failure rate, increase the probability of failure-free operation of the thermoelectric cooler and control the reliability indicators of the device of a given design during operation.

Structural-and-Parametric Optimization of Automatic Control System for Power Units of 300 MW in Wide Range of Load Variations

The structural-parametric optimization of the automatic control system for power units (ACSPU) of 300 MW of Lukoml’skaya GRES (Lukoml Local Condensing Power Plant) in the mode of both the permanent and the variable superheated steam pressure upstream of the turbine is under consideration. During 1974–1979, eight units of the Lukoml’skaya GRES implemented the ACSPU with a leading boiler power control. At the moment, these systems no longer meet all the frequency control quality requirements. In 2016, the daily schedule of electric loads of the Belarusian power system was as follows: the basic part of the schedule of electric loads was covered by combined heat and power plants (CHP) and by mini-CHP (which are the least maneuverable of the power plants), the semi-peak part of it–by local condensing power plants (Lukoml’skaya GRES and Berezovskaya GRES), the peak part–by import electric energy from neighboring power systems. However, this year the first unit of the Belorussian NPP will be put into operation, while the second one–in 2020. After the launch of the Belorussian NPP, it will cover basic part of load curve; CPPs will cover the semi-peak part, while the peak part of load curve will be covered by local condensing power plants. Correspondingly, due to the alteration of the structure of daily schedule of electric loads of the Belarusian power system, it is necessary to improve the efficiency of power units of Lukoml’skaya GRES as well as of the entire Lukoml’skaya GRES in general. This can be achieved with the help of the method of parametric optimization of the typical ACSPU proposed in the present paper. As a result, the quality of control of power and pressure upstream of the turbine will be improved; the flow of fuel will be reduced, as well as the turbine regulation valve displacement; environmental performance of entire power plant will be improved, too. The proposed technique has been confirmed by the results of computer simulation of transient processes in the automatic control system under external and internal disturbances.

Control systems design: the technology of simulation and optimization

The simulation and optimization technology is proposed for creating control systems that are designed for heat and power facilities. This paper presents an automatic feed control system of steam generators in the nuclear power plant unit on the basis of microprocessor controllers. The technology of simulation and optimization combines the methods of statistical modelling of disturbance signals, the control system simulation and the controller parameters optimization using genetic algorithm. As the initial data for the model design, we used archival information about processes on the existing unit equipment. The results of simulation studies and optimization of automatic control system’s parameters are derived in MATLAB.

SENSITIVITY OF CHARACTERISTICS OF MODEL OF THE ELECTRIC ARC TO CHANGE OF PARAMETERS OF ELEMENTS

Purpose. Consideration of the quantitative assessment of the sensitivity of certain properties of the automatic system to changes in the parameters of elements of only a part of the controlled object - the welding arc.Methodology. When solving practical problems of regulation by electric arc and plasma technological processes, it is important to solve the problem of determining the optimal settings or parametric optimization of automatic control systems, among the methods of which are non-exploratory methods based on the use of the sensitivity apparatus.Findings. The sensitivity to changes in the parameters of the nominal transfer function of the arc was analyzed, expressions for the sensitivity functions were obtained, and graphs of the corresponding functions were plotted. For more precision, it is assumed that changes in parameters are caused by changes in capacity, which always takes place in circuits with an arc.Originality. The problem of finding an acceptable compromise between the requirements of a small value of the stabilization error without a significant increase in the value of the input variable is formulated and solved.Practical value. Various rules have been developed to reduce the sensitivity of the transfer function of an object with respect to possible, unexpected changes in the parameters of a controlled object, which can be used in the design of high-quality transistor current sources for arc loads. To illustrate the sensitivity of the transfer function of the arc, the model shows the response to a stepwise change in input for different cases. Unfortunately, the article does not consider the characteristics of the disturbance and noise suppression, but only some options for reducing the sensitivity function are studied.

Parametric Optimization for Automatic Control System of Power Units of 300 MW for the Mode of Variable Pressure of Turbine Inlet Steam

The article deals with the problem of parametric optimization of automatic control systems for power units of 300 MW of Lukoml’skaya GRES in the mode of variable pressure of turbine inlet superheated steam. The modernization of automatic power control systems of all power units of Lukoml’skaya GRES was carried out in the nineties of XX century for the last time. At the moment, these systems no longer meet all the requirements of the new standard, which regulates the participation rates of thermal power units in the normalized primary frequency control and in automatic secondary control of frequency and active power flows. According to this standard, the time to achieve the half value of the required power change should be 10 seconds within the normal and emergency reserves; the time to achieve the full value of the required power change should be 30 seconds within the normal reserve and 2 minutes within the emergency one. The construction of the Belarusian NPP is also being completed; its first unit will be put into operation in 2019, and the second one–in 2020. After the launch of the NPP, the Lukoml’skaya GRES power units will be necessitated to operate in a wide range of load changes. It is for these reasons that it is necessary to improve the efficiency of power units in particular and of the entire power plant in general. This can be achieved with the help of the outlined method of parametric optimization of a typical system of automatic control of power units, which allows improving the quality of control of turbine inlet steam power and pressure. The results of computer simulation of transient processes in the system illustrate the technique described in this article and confirm its correctness and undoubted advantages over other methods of optimization of typical systems of automatic control of power units.

Parametric Optimization for Automatic Control System of 300 MW Power Units at a Constant Steam Pressure Upstream of the Turbine

The problem of parametric optimization of automatic control systems of power units (ACSPU) of 300 MW at the Lukoml’skaya GRES (Lukoml Condensing Power Plant) at a constant superheated steam pressure upstream of the turbine is under consideration. During 1974–1979, eight units of the Lukoml’skaya GRES implemented ACSPU with a leading boiler power control, which will be forced to work in a wide range of loads due to the planned commissioning of two power units of the Belarusian NPP: the first one – in 2019, and the second one – in 2020. The total capacity of the Belarusian Nuclear Power Plant will amount to 2400 MW. In addition, modern requirements for the regulation of the frequency and flows of active electric power in the power system have been tightened: the time to reach the half value of the required power alteration should be 10 seconds within the normal and emergency reserves; the time to reach the full value of the required power alteration should be 30 seconds within the range of the normal reserve and 2 minutes – within the range of the emergency reserve. With this regard, increasing the efficiency of the units operating in the variable part of the electric load schеdule by the use of modern methods of calculation of parameters of the dynamic adjustment of the regulating devices of ACSPU becomes an urgent problem. The methodology of parametric optimization of the typical ACSPU that make it possible to improve the quality of power regulation and the pressure of the superheated steam upstream of the turbine is presented. The described technique is illustrated by the results of computer simulation of transient processes in the system when the task and internal disturbances are worked out, which confirm the correctness of the proposed technique in comparison with the known methods of optimization of the typical ACSPU.

Gray Wolf optimization method for automatic ventilation systems of clean accessories

The manufacturing processes complication leads to cost increasing of equipment service and maintenance costs. An important role in overcoming these factors is played by modern automatic control systems, regulators optimization and adaptation of control systems to changing conditions. Today, the actual problem remains the adjustment and optimization of automatic control systems, especially complex structures.The article researches the population optimization algorithm "Gray wolf" as applied to the search for optimal PID-controller settings. A cascade automatic control system with two PID regulators optimized for a minimum of integral IAE, ISE quality criteria, as well as control time is considered. The advantage of the method under investigation is shown in a comparing with the Hook-Jeeves zero-order optimization method. The mathematical modeling of the automatic control system of air temperature in a clean room with the “Grey wolf” optimization method is performed. Attention is focused on the convenience of using the method, since it does not require an accurate setting of the initial parameters of the regulators. This eliminates the need for an a priori knowledge of the customizable system dynamics by the user. The commissioning of control parameters optimizing systems will help to increase the efficiency of the equipment in conditions of variable operating modes. The recommended area of the method used is the complex structures of automatic control systems, where the search for optimal settings by classical methods is difficult or does not exist.

Real-Time Optimization of Automatic Control Systems With Application to BLDC Motor Test Rig

Driven by the increasing demands on production quality, system performance, and the reliability and safety issues of process industry, this paper proposes an integrated process monitoring and control design technique for industrial control systems. The proposed approach is an alternative realization of Youla parameterization which allows the performance of the controlled systems to be improved without modifying or replacing the predesigned control systems, while the closed-loop stability is guaranteed. In addition, a residual signal is available for the fault detection and isolation purpose. The effectiveness and performance of the proposed approach are demonstrated on a brushless direct current motor test rig.

Automatic feed control of steam generator in the power unit of a nuclear power plant: Modeling and optimization

The paper presents the mathematical model of automatic feed control in the power unit of a nuclear power plant (NPP). As initial data for model design, archival information about industrial process in the power unit is used. We obtain the transfer function of a shaping filter for random signal generation with a required autocovariance function. The results of simulation studies and optimization of automatic control system's parameters using a genetic algorithm are produced.

Решение задач теории автоматического управления в программном комплексе "МВТУ"

The software package "MVTU" (Modeling in Technical Devices; in Russian - Modelirovanie V Tehnicheskih Ustrojstvah) is intended for research and design of the systems described by the differential, algebraic and difference equations. Complex technical object is a controlled object, therefore in the package "MVTU", along with the methods of simulation, the methods of control theory are implemented. In terms of features this package is an alternative of package Simulink, which is a part of system of mathematical computations MATLAB. As well as in the package Simulink, in the package "MVTU" representation of mathematical model in the form of block diagram is accepted. Blocks of such diagram are described by the differential and difference equations, continuous and discrete transfer functions, algebraic relations and logical conditions. The package "MVTU" implements the following operating modes. The operating mode Simulation provides simulation of continuous, discrete and hybrid systems, including in real time in the presence of data exchange with external programs and devices. The mode Optimization allows us to find optimum parameters of the designed system. The modes Analysis and Synthesis provide the solution of problems of research and design of control systems with use of frequency and root methods. The paper describes the main features of the package "MVTU" according to the solution of problems of the analysis, synthesis, simulation and parametric optimization of automatic control systems. Examples of the solution of such problems are given. Experience of the solution of a large number of educational, scientific and applied problems showed that the package MVTU doesn't concede by the opportunities to the best foreign analogs.

Modeling a Double-Zone Drafter as an Object of Control

The dynamics of the drafting process for cotton sliver is investigated with regard to its principal role in the synthesis and optimization of automatic control systems for reducing sliver irregularities. The approach is formal: the models refer to spectral filters, and the parameters of the respective transfer functions are determined by ad ditional signals—the speeds of the drafter rollers. Considering some trivial initial con ditions as given and using integral transformations of known initial equations, math ematical models in the form of transfer functions are obtained for a double-zone drafter with fibers of equal or different lengths. The drafter is presented as an object with four inputs and one output. The models are also presented in digital form as discrete transfer functions. To estimate model parameters, on-site experiments with harmonic test signals follow standard identification procedures. Time series with values of the object main signals have been registered synchronously using a digital data acquisition system with minimal sampling period. A specially designed software pack age is used to simulate process dynamics and the parts of the control system.

Use of a Digital Computer for the Optimization of Automatic Control Systems with Random Inputs†

ABSTRACT A Study is mode of Weiner's least-square optimization with quadratic constraints. The control system input consists of a random message plus noise. The message has a general form of power spectrum and the noise is white. Both message and noise are uncorrelated and stationary in the statistical sense. A digital computer is used to find the values of the Lagrange multipliers for given mean square constraints simultaneously imposed on two separate plant variables. The computation is performed by means of a specially devised goal-seeking programme.

The preparation of charts and tables for the optimization of automatic control systems with random inputs

The preparation of charts and tables for the optimization of automatic control systems with random inputs