scholarly journals Design of PI controller for Liquid Level System using Siemens Distributed Control System

2019 ◽  
Vol 8 (3) ◽  
pp. 2783-2789
Keyword(s):  
Time Delay ◽  
Stability Region ◽  
Dead Time ◽  
Pi Controller ◽  
Liquid Level ◽  
Order System ◽  
System Response ◽  
Level System ◽  
Geometric Center ◽  
The Stability

The PI controller design for a liquid level system using the weighted geometric center method is discussed. Every real-time process have dead time. This dead time leads to the generation of oscillation in the system response. The oscillation generated due to dead time introduces instability in system performance. This paper presents a tuning method based on calculating a geometric center in the stability region for a higher order system. In this, the stability region calculated by plotting (Kp , Ki )-plane based on boundary locus stability technique. Further centre point computed in the stability locus by a geometric center method. This center point will provide Kp , Ki value for tuning the PI controller. The First Order Plus Dead Time (FOPDT) process considered to elaborate the method for computing the tuning parameters. A nonlinear time-delay system and a plant having time-delay response are controlled in simulation. The performance of the newly obtained PI controller based on weighted geometric center method is compared with the existing results to show the usefulness of the control scheme. Moreover, disturbance rejection ability of the newly obtained PI controller based on weighted geometric center method is demonstrated by applying disturbances. In addition, the designed controller implemented using Siemens DCS PCS7 V8.1 platform.

The effects on stability region of the fractional-order PI controller for one-area time-delayed load–frequency control systems

2016 ◽  
Vol 39 (10) ◽  
pp. 1509-1521 ◽  
Author(s):  
Vedat Çelik ◽  
Mahmut Temel Özdemir ◽  
Gökay Bayrak
Keyword(s):  
Time Delay ◽  
Control Systems ◽  
Fractional Order ◽  
Stability Region ◽  
Fractional Integral ◽  
Frequency Control ◽  
Pi Controller ◽  
Load Frequency Control ◽  
Fractional Order Pi Controller ◽  
The Stability

One of the controllers used in load–frequency control systems is the PI controller, taking account of time delay originating from measurement and communication. In control systems, along with the use of the fractional-order controller, computing parameter space exhibited stable behaviour on the controller parameters and analysing its efficiency have become a significant issue. This study focuses on computing the effects of the fractional integral order ( α) on the stable parameter space for the control of a one-area delayed load–frequency control system in the case of a fractional-order PI controller. The effect of time delay on the stable parameter space is also investigated at different fractional integral orders ( α) in the time-delayed system with fractional-order PI controller. For this purpose, a characteristic equation of the delayed system with the fractional-order PI controller is obtained, and the stable parameter spaces of the controller are computed according to the fractional integral order ( α) and time delay ( τ) values using the stability boundary locus method, which is graphics based. Moreover, the generalized modified Mikhailov criterion is used for testing the stability region on the Kp − Ki plane. The obtained results verified that the stability region on the Kp − Ki plane change depending on the α and τ.

scholarly journals A New Method for Computing the Delay Margin for the Stability of Load Frequency Control Systems

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3460 ◽  
Author(s):  
Ashraf Khalil ◽  
Ang Swee Peng
Keyword(s):  
Time Delay ◽  
Power Systems ◽  
Control Systems ◽  
Frequency Control ◽  
Pi Controller ◽  
Load Frequency Control ◽  
New Method ◽  
Load Frequency ◽  
The Stability ◽  
Delay Margin

Open communication is an exigent need for future power systems, where time delay is unavoidable. In order to secure the stability of the grid, the frequency must remain within its limited range which is achieved through the load frequency control. Load frequency control signals are transmitted through communication networks which induce time delays that could destabilize power systems. So, in order to guarantee stability, the delay margin should be computed. In this paper, we present a new method for calculating the delay margin in load frequency control systems. The transcendental time delay characteristics equation is transformed into a frequency dependent equation. The spectral radius was used to find the frequencies at which the root crosses the imaginary axis. The crossing frequencies were determined through the sweeping test and the binary iteration algorithm. A one-area load frequency control system was chosen as a case study. The effectiveness of the proposed method was proven through comparison with the most recent published methods. The method shows its merit with less conservativeness and less computations. The impact of the proportional integral (PI) controller gains on the delay margin was investigated. It was found that increasing the PI controller gains reduces the delay margin.

An Efficient Approach for Stability Analysis and Parameter Tuning in Delayed Feedback Control of a Flying Robot Carrying a Suspended Load

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Wei Dong ◽  
Ye Ding ◽  
Luo Yang ◽  
Xinjun Sheng ◽  
Xiangyang Zhu
Keyword(s):  
Time Delay ◽  
Feedback Control ◽  
Spectral Radius ◽  
Stability Region ◽  
Parameter Tuning ◽  
Suspended Load ◽  
Delayed Feedback ◽  
Delayed Feedback Control ◽  
The Stability ◽  
Flying Robot

This paper presents an accurate and computationally efficient time-domain design method for the stability region determination and optimal parameter tuning of delayed feedback control of a flying robot carrying a suspended load. This work first utilizes a first-order time-delay (FOTD) equation to describe the performance of the flying robot, and the suspended load is treated as a flying pendulum. Thereafter, a typical delayed feedback controller is implemented, and the state-space equation of the whole system is derived and described as a periodic time-delay system. On this basis, the differential quadrature method is adopted to estimate the time-derivative of the state vector at concerned sampling grid point. In such a case, the transition matrix between adjacent time-delay duration can be obtained explicitly. The stability region of the feedback system is thereby within the unit circle of spectral radius of this transition matrix, and the minimum spectral radius within the unit circle guarantees fast tracking error decay. The proposed approach is also further illustrated to be able to be applied to some more sophisticated delayed feedback system, such as the input shaping with feedback control. To enhance the efficiency and robustness of parameter optimization, the derivatives of the spectral radius regarding the parameters are also presented explicitly. Finally, extensive numeric simulations and experiments are conducted to verify the effectiveness of the proposed method, and the results show that the proposed strategy efficiently estimates the optimal control parameters as well as the stability region. On this basis, the suspended load can effectively track the pre-assigned trajectory without large oscillations.

SYNCHRONIZATION OF TIME-DELAYED T–S FUZZY CHAOTIC SYSTEMS VIA SCALAR OUTPUT VARIABLE

2005 ◽  
Vol 15 (08) ◽  
pp. 2593-2601 ◽  
Author(s):  
JAE-HUN KIM ◽  
HYUNSEOK SHIN ◽  
EUNTAI KIM ◽  
MIGNON PARK
Keyword(s):  
Time Delay ◽  
Fuzzy Model ◽  
Order System ◽  
Linear Matrix ◽  
Output Variable ◽  
First Order ◽  
Scalar Output ◽  
The Stability ◽  
Takagi Sugeno ◽  
System With Time Delay

It has been known that very complex chaotic behaviors can be observed in a simple first-order system with time-delay. This paper presents a fuzzy model-based approach for synchronization of time-delayed chaotic system via a scalar output variable. Takagi–Sugeno (T–S) fuzzy model can represent a general class of nonlinear system and we employ it for fuzzy modeling of the chaotic drive and response system with time-delay. Since only a scalar output variable is available for synchronization, a fuzzy observer based on T–S fuzzy model is designed and applied to chaotic synchronization. We analyze the stability of the overall fuzzy synchronization system by applying Lyapunov–Krasovskii theory and derive stability conditions by solving linear matrix inequalities (LMI's) problem. A numerical example is given to demonstrate the validity of the proposed synchronization approach.

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