A new modeling and control scheme for thyristor-controlled series capacitor

2009 ◽  
Vol 7 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Zhizhong Mao
2007 ◽  
Vol 31 (1) ◽  
pp. 127-141
Author(s):  
Yonghong Tan ◽  
Xinlong Zhao

A hysteretic operator is proposed to set up an expanded input space so as to transform the multi-valued mapping of hysteresis to a one-to-one mapping so that the neural networks can be applied to model of the behavior of hysteresis. Based on the proposed neural modeling strategy for hysteresis, a pseudo control scheme is developed to handle the control of nonlinear dynamic systems with hysteresis. A neural estimator is constructed to predict the system residual so that it avoids constructing the inverse model of hysteresis. Thus, the control strategy can be used for the case where the output of hysteresis is unmeasurable directly. Then, the corresponding adaptive control strategy is presented. The application of the novel modeling approach to hysteresis in a piezoelectric actuator is illustrated. Then a numerical example of using the proposed control strategy for a nonlinear system with hysteresis is presented.


Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1243
Author(s):  
Dimitris Ipsakis ◽  
Theodoros Damartzis ◽  
Simira Papadopoulou ◽  
Spyros Voutetakis

The present work aims to provide insights into the dynamic operation of a coupled reformer/combustion unit that can utilize a variety of saturated hydrocarbons (HCs) with 1–4 C atoms towards H2 production (along with CO2). Within this concept, a preselected HC-based feedstock enters a steam reforming reactor for the production of H2 via a series of catalytic reactions, whereas a sequential postprocessing unit (water gas shift reactor) is then utilized to increase H2 purity and minimize CO. The core unit of the overall system is the combustor that is coupled with the reformer reactor and continuously provides heat (a) for sustaining the prevailing endothermic reforming reactions and (b) for the process feed streams. The dynamic model as it is initially developed, consists of ordinary differential equations that capture the main physicochemical phenomena taking place at each subsystem (energy and mass balances) and is compared against available thermodynamic data (temperature and concentration). Further on, a distributed control scheme based on PID (Proportional–Integral–Derivative) controllers (each one tuned via Ziegler–Nichols/Z-N methodology) is applied and a set of case studies is formulated. The aim of the control scheme is to maintain the selected process-controlled variables within their predefined set-points, despite the emergence of sudden disturbances. It was revealed that the accurately tuned controllers lead to (a) a quick start-up operation, (b) minimum overshoot (especially regarding the sensitive reactor temperature), (c) zero offset from the desired operating set-points, and (d) quick settling during disturbance emergence.


1985 ◽  
Vol 107 (3) ◽  
pp. 200-206 ◽  
Author(s):  
Y. Sakawa ◽  
A. Nakazumi

In this paper we first derive a dynamical model for the control of a rotary crane, which makes three kinds of motion (rotation, load hoisting, and boom hoisting) simultaneously. The goal is to transfer a load to a desired place in such a way that at the end of transfer the swing of the load decays as quickly as possible. We first apply an open-loop control input to the system such that the state of the system can be transferred to a neighborhood of the equilibrium state. Then we apply a feedback control signal so that the state of the system approaches the equilibrium state as quickly as possible. The results of computer simulation prove that the open-loop plus feedback control scheme works well.


Author(s):  
Nikhil Ravi ◽  
Matthew J. Roelle ◽  
Hsien-Hsin Liao ◽  
Adam F. Jungkunz ◽  
Chen-Fang Chang ◽  
...  

Homogeneous charge compression ignition (HCCI) is one of the most promising piston-engine concepts for the future, providing significantly improved efficiency and emissions characteristics relative to current technologies. This paper presents a framework for controlling a multi-cylinder HCCI engine with exhaust recompression and direct injection of fuel into the cylinder. A physical model is used to describe the HCCI process, with the model states being closely linked to the thermodynamic state of the cylinder constituents. Separability between the effects of the control inputs on the desired outputs provides an opportunity to develop a simple linear control scheme, where the fuel is used to control the work output and the valve timings are used to control the phasing of combustion. Experimental results show good tracking of both the work output and combustion phasing over a wide operating region. In addition, the controller is able to balance out differences between cylinders, and reduce the cycle-to-cycle variability of combustion.


2009 ◽  
Vol 132 (1) ◽  
Author(s):  
C. R. MacLaine ◽  
P. Acarnley ◽  
J. Shanahan ◽  
P. Mousalli ◽  
M. Deighton

Many industrial processes involve the transportation of a continuous web of material over a series of rollers to obtain a finished product. The manufacture of polymer film is one such web transport process, which utilizes a series of rotating elements that act to manipulate the film. This paper develops a dynamic mathematical model of the “forward draw” in a polymer film production process. The model is capable of being implemented in real-time for control purposes, yet includes significant physical phenomena such as material damping. Experimental results from a pilot production plant are used to validate the model under steady-state and transient conditions. The model is then used as a basis for a feed-forward control scheme, which reduces speed variations in the forward draw by a factor of 8 and therefore improves considerably the film quality.


1988 ◽  
Vol 110 (3) ◽  
pp. 266-271 ◽  
Author(s):  
Kamal A. F. Moustafa ◽  
A. M. Ebeid

In this paper, we derive a nonlinear dynamical model for an overhead crane. The model takes into account simultaneous travel and transverse motions of the crane. The aim is to transport an object along a specified transport route in such a way that the swing angles are suppressed as quickly as possible. We develop an antiswing control system which adopts a feedback control to specify the crane speed at every moment. The gain matrix is chosen such that a desired rate of decay of the swing angles is obtained. The model and control scheme are simulated on a digital computer and the results prove that the feedback control works well.


2014 ◽  
Vol 25 (02) ◽  
pp. 255-282 ◽  
Author(s):  
Alfio Borzì ◽  
Suttida Wongkaew

A new refined flocking model that includes self-propelling, friction, attraction and repulsion, and alignment features is presented. This model takes into account various behavioral phenomena observed in biological and social systems. In addition, the presence of a leader is included in the system in order to develop a control strategy for the flocking model to accomplish desired objectives. Specifically, a model predictive control scheme is proposed that requires the solution of a sequence of open-loop optimality systems. An accurate Runge–Kutta scheme to discretize the optimality systems and a nonlinear conjugate gradient solver are implemented and discussed. Numerical experiments are performed that investigate the properties of the refined flocking model and demonstrate the ability of the control strategy to drive the flocking system to attain a desired target configuration and to follow a given trajectory.


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