scholarly journals Adjustment of the PID Gains Vector Due to Parametric Variations in the Plant Model in Terms of Internal Product

2021 ◽  
Author(s):  
José Pinheiro de Moura ◽  
João Viana da Fonseca Neto
Keyword(s):  
Industrial Processes ◽  
Pid Controllers ◽  
Promising Alternative ◽  
Plant Model ◽  
Bulk Solids ◽  
Parameter Variations ◽  
Plant Transfer ◽  
Propagation Matrix ◽  
Plant Parameter ◽  
Specific Project

The tuning of the gains of a controller with proportional-integral-derivative (PID) actions has been prevalent in the industry. The adjustment of these gains in PID controllers is often determined by classical methods, such as Ziegler-Nichols, and trial and error. However, these methods fail to deliver satisfactory performance and often do not meet specific project demands because of the inherent complexity of industrial processes, such as plant parameter variations. To solve the tuning problem in highly complex industrial processes, a controller adjustment method based on the internal product of PID terms is proposed, and a propagation matrix (PM) is generated by the numerator coefficients of the plant transfer function (TF). In the proposed method, each term of the PID controller is influenced by each of the numerator and the denominator coefficients. Mathematical models of practical plants, such as unloading and resumption of bulk solids by car dumpers and bucket wheel resumption, were employed to evaluate the proposed method. The obtained results demonstrated an assertive improvement in the adjustment gains from PID actions, thereby validating it as a promising alternative to conventional methods.

scholarly journals Advanced Kinetic Modeling of Bio-co-polymer Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Production Using Fructose and Propionate as Carbon Sources

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1260
Author(s):  
Stefanie Duvigneau ◽  
Robert Dürr ◽  
Jessica Behrens ◽  
Achim Kienle
Keyword(s):  
Kinetic Model ◽  
Kinetic Modeling ◽  
Feed Rate ◽  
Raw Materials ◽  
Carbon Sources ◽  
Exhaust Gas ◽  
Current Yield ◽  
Promising Alternative ◽  
Parameter Variations ◽  
Online Measurements

Biopolymers are a promising alternative to petroleum-based plastic raw materials. They are bio-based, non-toxic and degradable under environmental conditions. In addition to the homopolymer poly(3-hydroxybutyrate) (PHB), there are a number of co-polymers that have a broad range of applications and are easier to process in comparison to PHB. The most prominent representative from this group of bio-copolymers is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). In this article, we show a new kinetic model that describes the PHBV production from fructose and propionic acid in Cupriavidus necator (C. necator). The developed model is used to analyze the effects of process parameter variations such as the CO2 amount in the exhaust gas and the feed rate. The presented model is a valuable tool to improve the microbial PHBV production process. Due to the coupling of CO2 online measurements in the exhaust gas to the biomass production, the model has the potential to predict the composition and the current yield of PHBV in the ongoing process.

Complementary Sensitivity Design of PID Controllers for Arbitrary-Order Transfer Functions With Time Delay

2008 ◽  
Author(s):  
Tooran Emami ◽  
John M. Watkins
Keyword(s):  
Time Delay ◽  
Transfer Functions ◽  
Linear Time ◽  
Order System ◽  
Pid Controllers ◽  
Single Input Single Output ◽  
Linear Time Invariant ◽  
Single Output ◽  
Plant Transfer ◽  
Time Invariant

A graphical technique for finding all proportional integral derivative (PID) controllers that stabilize a given single-input-single-output (SISO) linear time-invariant (LTI) system of any order system with time delay has been solved. In this paper a method is introduced that finds all PID controllers that also satisfy an H∞ complementary sensitivity constraint. This problem can be solved by finding all PID controllers that simultaneously stabilize the closed-loop characteristic polynomial and satisfy constraints defined by a set of related complex polynomials. A key advantage of this procedure is the fact that it does not require the plant transfer function, only its frequency response.

scholarly journals The Role of H-bonding in Phase Change Materials

2019 ◽  
Author(s):  
Karolina Matuszek ◽  
R. Vijayaraghavan ◽  
Mega Kar ◽  
Douglas Macfarlane
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hirshfeld Surface ◽  
Industrial Processes ◽  
Heat Of Fusion ◽  
Organic Salts ◽  
Promising Alternative

Phase change materials (PCMs) which melt in the temperature range of 100-230 °C, are a promising alternative for the storage of thermal energy. In this range, large amounts of energy available from solar-thermal, or other forms of renewable heat, can be stored and applied to domestic or industrial processes, or to an Organic Rankine Cycle (ORC) engine to generate electricity. The amount of energy absorbed is related to the latent heat of fusion (ΔH<sub>f</sub>) and is often connected to the extent of hydrogen bonding in the PCM. Herein, we report fundamental studies, including crystal structure and Hirshfeld surface analysis, of a family of guanidinium organic salts that exhibit high values of ΔH<sub>f</sub>, demonstrating that the presence and strength of H-bonds between ions plays a key role in this property.

Design of Advanced Controllers for Pressure Control in Nuclear Reactors: A General Approach

2014 ◽  
Author(s):  
M. Cappelli ◽  
B. Castillo-Toledo ◽  
S. Di Gennaro
Keyword(s):  
Process Model ◽  
Sliding Mode ◽  
Fundamental Property ◽  
Pressure Control ◽  
Reactor Power ◽  
Pid Controllers ◽  
Primary Circuit ◽  
Direct Measurements ◽  
Control Scheme ◽  
Parameter Variations

When a failure occurs in a nuclear plant, a lack in the response of the controller could lead to serious consequences. The fundamental property to be ensured by the controller is the plant stability, possibly proved formally, and at least in the range of validity of the process model. In this work, using a mathematical model for the primary circuit of a PWR, accurate enough to catch the nonlinear, time–varying, and switching nature of the system, and suitable for the control purposes, the reactor power controller, the inventory controller for the primary circuit, and the pressurizer pressure controllers are designed. These controllers do not use direct measurements of the pressurizer pressure or temperature, but they use instead pressurizer wall temperature measurements. Disturbances and parameter variations are compensated by the use of sliding–mode terms, which guarantee further robustness to the control scheme. The switching nature of the controller, reflecting the switching nature of the pressurizer dynamics, and the nonlinear terms implemented in the controllers, along with classical PI actions, ensure better transient behaviors. Hence, they represent an evolution and an improvement with respect to classical PID controllers, usually implemented in standard control actions.

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