A Study on Parameter Tuning of Fractional Order PIλ-PDμ Controller

2014 ◽  
Vol 1049-1050 ◽  
pp. 977-982
Author(s):  
Hui Juan Bian ◽  
Zhi Dong Qi ◽  
Liang Shan ◽  
Bo Yang Leng
Keyword(s):  
Fractional Order ◽  
Feedback Loop ◽  
Closed Loop ◽  
Control Structure ◽  
Dynamic Performance ◽  
Parameter Tuning ◽  
Order System ◽  
Reasonable Range ◽  
Static Performance ◽  
Forward Channel

Aiming at a kind of special object with fractional characteristics,a new kind of fractional order PIλ-PDμ controller is put forward in this paper,In this control system, the forward channel of system contains a fractional order PIλ controller,while the feedback loop adopts PDμ controller.The control structure in this fractional order system can achieve a good performance of the closed loop control.Moreover,the impacts on system dynamic performance and static performance are compared when the parameters in the controller are changed.The results show that when these parameters are in the reasonable range,the system can achieve better control performance.

A High-Frequency Inverter Based on Double Closed-Loop Control

2012 ◽  
Vol 241-244 ◽  
pp. 509-512
Author(s):  
Lin Yang ◽  
Gen Wang Liu
Keyword(s):  
High Frequency ◽  
Closed Loop ◽  
Control Structure ◽  
Dynamic Performance ◽  
Current Loop ◽  
Closed Loop Control ◽  
Voltage Waveform ◽  
Loop Control ◽  
Static Performance ◽  
Frequency Inverter

In order to improve the dynamic performance of inverter and the output voltage waveform quality, the double-loop control combination with internal current loop and external voltage loop is introduced. The inner loop is used for improving the dynamic performance of the system and rapidly eliminating the effects of load disturbance; the outer loop is used for improving static performance of the system. In the end, MATLAB / Simulink is carried out to build the system model and prove the feasibility of the dual closed-loop control structure in this paper.

Enhanced Fractional Order Sliding Mode Approach for Maximum Power Tracking of Five-phase PMSG based WECS

2021 ◽  
Vol 12 (5) ◽  
pp. 918-929
Author(s):  
Salah Eddine Rhaili Et. al.
Keyword(s):  
Power Systems ◽  
Fractional Order ◽  
Sliding Mode ◽  
Control Function ◽  
Dynamic Performance ◽  
Electrical Power ◽  
Variable Structure ◽  
Synchronous Generator ◽  
Lyapunov Theory ◽  
Static Performance

Variable structure strategies have shown an efficient performance in controlling nonlinear electrical power systems by reason of its strength to handle perfectly the unmodeled system dynamics. In this study, with the exponent reaching law, a robust enhancement method of sliding mode controller (SMC) based on a nonlinear fractional order sliding surface that consists of both fractional differentiation and integration is proposed and applied to control a high-power multiphase permanent magnet synchronous generator based direct-driven Wind Energy Conversion System (WECS), in order to improve the energy efficiency and reduce the produced chattering phenomenon of conventional SMC . Moreover, a new smooth and derivable nonlinear switching control function is applied to replace the traditional non-derivable nonlinear control law, to improve dynamic performance, static performance, and robustness of the system. The proposed strategy stability is investigated under Lyapunov theory. A comparative simulation of the new proposed approach with the conventional SMC and PI controller display the excellent performance, stability and high robustness of FOSMC, by improving the system efficiency up to 98.66%, compared to conventional SMC with 91,14%, while the PI control achieves 86, 2%.

scholarly journals Modified Projective Synchronization between Different Fractional-Order Systems Based on Open-Plus-Closed-Loop Control and Its Application in Image Encryption

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Hongjuan Liu ◽  
Zhiliang Zhu ◽  
Hai Yu ◽  
Qian Zhu
Keyword(s):  
Fractional Order ◽  
Closed Loop ◽  
Sufficient Conditions ◽  
Projective Synchronization ◽  
Order System ◽  
Coupling Scheme ◽  
Fractional Order Systems ◽  
Parameter Mismatch ◽  
Loop Control ◽  
Modified Projective Synchronization

A new general and systematic coupling scheme is developed to achieve the modified projective synchronization (MPS) of different fractional-order systems under parameter mismatch via the Open-Plus-Closed-Loop (OPCL) control. Based on the stability theorem of linear fractional-order systems, some sufficient conditions for MPS are proposed. Two groups of numerical simulations on the incommensurate fraction-order system and commensurate fraction-order system are presented to justify the theoretical analysis. Due to the unpredictability of the scale factors and the use of fractional-order systems, the chaotic data from the MPS is selected to encrypt a plain image to obtain higher security. Simulation results show that our method is efficient with a large key space, high sensitivity to encryption keys, resistance to attack of differential attacks, and statistical analysis.

scholarly journals Fractional-Order Sliding Mode Control of Overhead Cranes   

2020 ◽  
Vol 31 (1) ◽  
pp. 68-76
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Closed Loop ◽  
Control Structure ◽  
Adaptive System ◽  
Sliding Mode ◽  
Lyapunov Theory ◽  
Closed Loop System ◽  
Control Approach ◽  
Mode Control

We constitute a control system for overhead crane with simultaneous motion of trolley and payload hoist to destinations and suppression of payload swing. Controller core made by sliding mode control (SMC) assures the robustness. This control structure is inflexible since using fixed gains. For overcoming this weakness, we integrate variable fractional-order derivative into SMC that leads to an adaptive system with adjustable parameters. We use Mittag–Leffler stability, an enhanced version of Lyapunov theory, to analyze the convergence of closed-loop system. Applying the controller to a practical crane shows the efficiency of proposed control approach. The controller works well and keeps the output responses consistent despite the large variation of crane parameters.

Adaptive LMS Model-Following Control Applied Inside a Closed-Loop

1997 ◽  
Author(s):  
Bradley R. Smith ◽  
H. H. Robertshaw
Keyword(s):  
Feedback Loop ◽  
Closed Loop ◽  
Delay Line ◽  
Second Order ◽  
Order System ◽  
Control Problems ◽  
Model Following Control ◽  
Model Following ◽  
Adaptive Lms ◽  
Unknown Solution

Abstract A Least Mean Squares (LMS)-style algorithm is derived for the feedback control problem. The algorithm allows a tap delay line within the closed loop to be used for control applications. This paper derives the algorithm and applies the algorithm to two simple control problems for which the solution is known and to one problem with an unknown solution. The first problem is a stable second-order system. The second problem is a unstable second-order system which is initially stabilized with the feedback loop. In both problems, the weights converge to the expected values. The stable problem is used again with an inaccurate model that has 50% more damping than the actual plant. The weights converge to a solution which increases the performance of the controller.

scholarly journals Approximation Methods for FO-IMC Controllers for Time Delay Systems

2019 ◽  
Vol 115 ◽  
pp. 01003
Author(s):  
Cristina I. Muresan ◽  
Isabela R. Birs ◽  
Ovidiu Prodan ◽  
Ioan Nascu ◽  
Robin De Keyser
Keyword(s):  
Time Delay ◽  
Fractional Order ◽  
Approximation Method ◽  
Closed Loop ◽  
Internal Model Control ◽  
Delay Systems ◽  
Order System ◽  
Test Cases ◽  
Time Delay Systems ◽  
Model Control

Fractional Order Internal Model Control (FO-IMC) is among the newest trends in extending fractional calculus to the integer order control. Approximation of the FO-IMC is one of the key problems. Apart from this, when dealing with time delay systems, the time delay needs also to be approximated. All these approximations can alter the closed loop performance of the controller. In this paper, FO-IMC controllers will be tested in terms of the approximation accuracy. The case study is a first order system with time delay. Several scenarios will be considered, aiming for a conclusion regarding the choice of the approximation method as a function of the process characteristics, closed loop performance and FO-IMC fractional order. To approximate the time delay, two extensively used techniques will be considered, such as the series and Pade approximations. These will be compared to a novel approximation technique. An analysis of the test cases presented show that the series approximation proves more suitable in a single scenario, whereas the novel approximation method produces better results for the rest of the test cases.

Internal Model Control–Proportional Integral Derivative–Fractional-Order Filter Controllers Design for Unstable Delay Systems

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Kahina Titouche ◽  
Rachid Mansouri ◽  
Maamar Bettayeb ◽  
Ubaid M. Al-Saggaf
Keyword(s):  
Fractional Order ◽  
Internal Model ◽  
Closed Loop ◽  
Control Structure ◽  
Internal Model Control ◽  
Loop System ◽  
Proportional Integral Derivative ◽  
Closed Loop System ◽  
Proportional Integral ◽  
Model Control

An analytical design for proportional integral derivative (PID) controller cascaded with a fractional-order filter is proposed for first-order unstable processes with time delay. The design algorithm is based on the internal model control (IMC) paradigm. A two degrees-of-freedom (2DOF) control structure is used to improve the performance of the closed-loop system. In the 2DOF control structure, an integer order controller is used to stabilize the inner-loop, and a fractional-order controller for the stabilized system is employed to improve the performance of the closed-loop system. The Walton–Marshall's method, which is applicable to quasi-polynomials, is then used to establish the internal stability condition of the closed-loop system (the fractional part of the controller in particular) and to seek the set of stabilizing proportional (P) or proportional-derivative (PD) controller parameters.

Sign in / Sign up

Export Citation Format

Share Document