Mathematical Modelling and Simulation of the Behaviour of the Steam Turbine

AbstractModel simulations are becoming very important in dynamic power system analyses. However, no mathematical system can exactly model a physical process. Based on mathematical models of the processes and design calculations, PC programs allow simulation and the determination of the control system performances. This paper presents the mathematical modelling of the steam turbine unit, developed based on the continuity equation. This model is used to determine the simulation diagram for the steam turbine with high, medium and low pressure sections. Using Matlab/Simulink software facilities, have been simulated the behaviour of the shaft torque, depending of the control valves opening, with uncertain parameters of the process, than the step response of the steam turbine, with load and proportional control algorithm

Model Reference Adaptive Control Design for Slow Processes. A Case Study on Level Process Control

AbstractThe design of controllers, using conventional techniques, for plants with nonlinear dynamics or model uncertainties can be often quite difficult. Model reference adaptive control (MRAC) is a modern alternative for classic control algorithms and a convenient method to updating the controller's parameters for slow processes with parameter variations. In this paper is presented a comparative study of two design procedures of MRAC for first order slow processes, particularly applied and tested on level process control. The first method it is based on the MIT rule and the second one it is based on the stability theory of Lyapunov. The theoretical results are obtained using Matlab simulation environment

Modeling and Simulation of the Operation of a Mechanical System which is Affected by Uncertainties

AbstractIn control engineering, the mathematical model of the studied process plays an important part. In representing the mathematical model, the inherent errors due to parameter variations define the parametric (structured) uncertainties; therefore there are differences between the mathematical model used in the design process and the real plant. In most cases, the control system needs to stabilize the process and also needs to assure certain performances even in the presence of uncertainties, unmodeled dynamics, disturbance signals and measurement noise, which all make the process vulnerable.This paper shows a method for behavioral modeling and simulation of a gear system, in which the moment of inertia and the friction coefficient represent the parameters which are affected by uncertainties, and are expressed by percentages to the nominal values. For the modeled process, by considering a classical controller, which is tuned experimentally, Matlab is used to represent the sensitivity functions in both time and frequency domains for the nominal cases, for randomly generated samples and for the worst case scenarios

The Effects of Weighting Functions on the Performances of Robust Control Systems

An important stage in robust control design is to define the desired performances of the closed loop control system using the models of the frequency sensitivity functions S. If the frequency sensitivity functions remain within the limits imposed by these models, the control performances are met. In terms of the sensitivity functions, the specifications include: shape of S over selected frequency ranges, peak magnitude of S, bandwidth frequency, and tracking error at selected frequencies. In this context, this paper presents a study of the effects of the specifications of the weighting functions on the performances of robust control systems

Estimation of the Processing Parameters in Electron Beam Thermal Treatments

Electron beam have many special properties which make them particularly well suited for use in materials handling through melting, welding, surface treatment, etc., taking into account that this manufacturing is performed in vacuum. The use of electron beam for surface limited heat treatment of workpiece has brought about a noticeable extension of the beam technologies. Some theoretical aspects and simulation results are presented in this paper, considering a high power electron beam processing system and Matlab facilities. This paper can be used in power engineering and electro-technologies fields as a guideline, in order to simulate and analyse the process parameters

The simulation of the electron beam spot control

Electron beams have many special properties which make them particularly well suited for use in materials processing, wherever conventional techniques failed or proved to be inefficient. The entire process has a lot of time varying parameters, so using a distributed control system for 3d position of the electron beam spot may improve the quality of the material processing. Matlab environment was used for model implementation and simulations of the control system which contains the focusing and deflecting components. Due the nature of the process and knowing the electron beam equipment we proposed for the simulations scenarios with a 3D virtual surface