Implementation Of Digital Control System Research Articles

Design of Discrete and Hybrid Nonlinear Control Systems

In this article the new method of discrete control systems design for nonlinear plants with differentiable nonlinearities is suggested. The increasing demands on the quality of control processes and the widespread use of computer technology provide ample opportunities for the design and implementation of digital control systems. However, discrete models of control plants are needed to solve this problem. In the case of linear plants, such models are created on the basis of z-transformation, Euler or Tustin formulas. In the case of nonlinear plants, these transformations are not applicable, so a large number of approximate discretization methods have been developed to date. Euler and Runge-Kutt transformations are used for these purposes most often, but they lead to satisfactory results only with very small period of discretization. In the case of automatic control systems, this requires the use of digital automation tools with very high speed, which is often economically impractical. Methods of discretization with a long period were most often developed on the basis of decomposition into series of the right-hand sides of the differential equations, transformed on Euler. Here, firstly, the problem of selecting the number of the series members, which to be retained arises, and secondly, already in the third or fourth order of the plant, the calculating ratios turn out to be extremely complex. The discretization method suggested below differs in that it is not the equations of nonlinear plants in the Cauchy form that are discretized, but the corresponding quasilinear model. In this case, a modified trapezoid method is used, and the discretization purpose is not the most accurate approximation of the original equations of the plant, but the stability of a closed nonlinear control system with rather big period. This system is designed using the algebraic polynomial-matrix method for designing of the nonlinear control systems. As a result, a hybrid nonlinear system with fairly simple algebraic calculation expressions is formed. The suggested approach makes it possible to create the control systems for nonlinear controlled plants using conventional computational automation tools.

Организация информационной структуры цифровой системы оперативного управления работой станции

The article is devoted to the study of control systems for the operation of railway station, driven by the trend in the industry towards the development and implementation of digital control systems that increase the functionality of the technological means used. The analysis of automated control systems used on railways and in the metro is carried out, their advantages and disadvantages are described. It is shown that it is necessary to build a digital system of operational control of the station, which provides automation of such intellectual functions as planning operations, forming tasks and monitoring their implementation by responsible departments. In the presented work, the synthesis of the information structure of such a system is carried out, providing the receipt, transmission and processing of data, the source of which is currently operated automated railway transport systems for various purposes. The gates of the structure (databases, information arrays) are defined, their description is given, connections between them are built, implemented functions are described. The concept of a model unit as a data package describing the information stored in the system for each element of the technological process of the station is formulated. Examples of algorithms for the functioning of the described structure in terms of movement control and the formation of model units of rolling stock located in the control loop of the system are given. Possible directions for further research are formulated.

The implementation of a digital system for automatic continuous control object, based on a physical model of the object using a thermal Scada Zenon system

Purpose. Develop a methodology for the implementation of digital control systems for continuous objects on a personal computer, which should provide: bringing the temperature in the chamber to a given value at a given range of air flow in the system; maintaining the temperature in the chamber at a given level at a given range of air flow in the system; visualization and control of the stand of the thermal object; control of fan speed in order to create a disturbing effect; registration of process parameters in the thermal object. The methods. The development is carried out through the phased implementation of a digital control system for a continuous object, implemented on a personal computer. The proposed approach consists of the main stages: a controller is synthesized in a continuous form, which implements the proportional-integral-differential (PID) control law. The simulation of the obtained system is performed in the mathematical package MATLAB. At the next stage on the personal computer the software implementation of the synthesized digital regulator is executed. At the last stage, the hardware elements of the control system were developed and implemented. Findings. The use of this approach in the development of a system of automatic control of a continuous object on the basis of a thermal object allows you to effectively create a complete hardware and software part of digital SAC using Scada system Zenon. This will significantly reduce the duration and cost of commissioning of ACS in production conditions at the actual control facility. Which makes it possible to significantly reduce the duration and cost of commissioning of ACS in production conditions at the actual control facility. The originality. For the first time, a method of creating a control system for thermal objects, based on programmable logic controller with the synthesis of the system in the mathematical package MATLAB. Practical implimintation. The obtained data allow to bring the model as close as possible to the real control system and to perform effective testing of its functioning in non-production conditions.

Design and Implementation of Digital Control System Based on PAC Architecture for Large-Capacity Pulse Power Supply

In Tokamak device, many larger capacity pulsed power supplies have been installed to provide high-energy magnetic field to control plasma. In this article, a new digital control system for satisfying larger capacity pulse power supply is introduced. This control scheme uses programmable automation controller (PAC) architecture, which consists of software platform and hardware platform to design a new digital control system, and in this system, real-time operation system (OS) and real-time communication network can provide much more precise and predictable timing characteristics to fulfill the requirements of the real-time control for pulse power supply in Tokamak device. Its hardware architecture based on integration and modularization can provide reliability, stability, and flexibility for digital control application; meanwhile, its software platform is used to handle data communication, close-looping control, protection strategy execution, and trigger output. After the digital control system of the large-capacity pulse power supply is built, its performance is verified through the HL-2A experiments. The result shows that the digital control system achieves the design goals and has high reliability and stability.

Implementation of Controller Structures in FPGA Platform

Field Programmable Gate Arrays are recently replacing general purpose microcontrollers in implementation of digital control systems. This paper includes the proposal of implementing complex controller structures in a Field Programmable Gate Array (FPGA). Till recent, PID controllers are implemented in FPGA Platform. PID controllers are simple, reliable, versatile feedback mechanisms used in most control systems. To reduce various undesirable effects on the output such as overshoot, some variants in the conventional PID controllers, such as the I-PD and IMC are also used. Here all these control controller structures are implemented in MATLAB, compared for best performance and run in the FPGA.

Sensorless Direct Torque and Flux Controlled IPM Synchronous Machine Fed by Matrix Converter Over a Wide Speed Range

This paper proposes a new sensorless direct torque and flux controlled interior permanent magnet synchronous machine drive fed by a matrix converter. Closed-loop control of both torque and stator flux is achieved by using two PI controllers. The input and output voltage vectors are modulated with the indirect space vector modulation technique. Additionally, unity power factor on the power supply side of matrix converter is achieved through closed-loop compensation of the input displacement angle created by the input filter of matrix converter. The adaptive observer used for joint stator flux and rotor speed estimation is enhanced by HF signal injection scheme for stable operation at low speed including standstill. The stator resistance variation is compensated with the current estimation error. The operating range of the drive is extended into high speed region by incorporating field weakening. The sensorless drive exhibits high dynamic and steady-state performances over a wide speed range. The implementation of digital control system for the proposed matrix converter drive is described in this paper. Extensive experimental results confirming the effectiveness of the proposed method are also included.

Selection and Implementation of Digital Control Systems for KNPC Refineries: A Case Study

The steps taken to select and implement digital control systems for three Refineries owned by KNPC are explained. Two new refineries are designed to be controlled by a digital control system, and one is being revamped from conventional analog to digital. Revamping procedures are also described from the start of the project to the commissioning stage.