Implementation Of Fractional-order Controller Research Articles

Design and implementation of fractional-order controller in delta domain

In this work, a fractional-order controller (FOC) is designed in a discrete domain using delta operator parameterization. FOC gets rationally approximated using continued fraction expansion (CFE) in the delta domain. Whenever discretization of any continuous-time system takes place, the choice of sampling time becomes the most critical parameter to get most accurate results. Obtaining a higher sampling rate using conventional shift operator parameterization is not possible and delta operator parameterized discretize time system takes the advantages to circumvent the problem associated with the shift operator parameterization at a high sampling limit. In this work, a first-order plant with delay is considered to be controlled with FOC, and is implemented in discrete delta domain. The plant model is designed using MATLas well as in hardware. The fractional-order controller is tuned in the continuous domain and discretized in delta domain to make the discrete delta FOC. Continuous time fractional order operator (s??) is directly discretized in delta domain to get the overall FOC in discrete domain. The designed controller in implemented using MATLABSimulink and dSPACE board such that dSPACEboard acts as the hardware implemented FOC. The step response characteristics of the closed-loop system using delta domain FOC resembles to that of the results obtained by continuous time controller. It proves that at a high sampling rate, the continuous-time result and discrete-time result are obtained hand to hand rather than the two individual cases. Therefore, the analysis and design of FOC parameterized with delta operator opens up a new area in the design and implementation of discrete FOC, which unifies both continuous and discrete-time results. The discrete model performance characteristics are evaluated in software simulation using MATLAB, and results are validated through the hardware implementation using dSPACE.

Theory and Implementation of Fractional Order Controllers for Power System Applications

The paper presents the theoretical foundation and practical implementation aspects of Fractional Order Controllers (FOCs) for power system applications. With this aim, the paper provides a comprehensive mathematical background on the stability analysis of dynamic systems with inclusion of fractional order derivatives and discusses their software implementation based on the Oustaloup's Recursive Approximation (ORA) method. Then the paper illustrates a variety of examples of ORA-based FOCs, namely, automatic generation control of synchronous machines; frequency control of a converter-interfaced energy storage system; and voltage control through a static synchronous compensator. The WSCC 9-bus test system and a realistic 1,479-bus model of the Irish transmission system are employed to test and compare the examined FOCs with their integer-order versions.

Synthesis and implementation of fractional-order controllers in a current curcuit of the motor with series excitation

We have synthesized and investigated fractional-order regulators, which provide for a series of technological processes the best indicators for the quality of transient process, specifically DC motors with series excitation. Given the dependence of magnetic flux on the armature current and saturation of the magnetic system, a motor armature circuit turns into a system with significant nonlinear properties under static and dynamic modes. However, it can be described with high accuracy by the transfer function of fractional order. Owing to the appropriate fractional integral-differentiating regulators, it becomes possible to obtain the quality of transient processes that is better than when using classic methods. We have considered standard methods to synthesize the coefficients of regulators and established that such settings result in deterioration of transients due to the saturation of regulators, caused by power supply voltage limitation. Therefore, it has been proposed, for a closed circuit with different structures of fractional regulators, to use a genetic algorithm for determining the optimal values of the coefficients of regulators based on the criterion for the shortest time of first harmonization and minimum overshoot. Experimental study into different structures of regulators has been performed conducted for settings on the module optimum and a fractional order of astatism from 0.35 to 1.5. Based on the results obtained, it can be argued that the best indicators are demonstrated by regulators at astatism 1+μ co , 1.5. The overshoot is then actually less than 2 %. It has been also shown that astatism 1+μ co ensures high-quality of transient processes in the unsaturated zone of magnetic system as well. The research results could be used primarily in the systems of closed control in DC motors with series excitation, as well as with objects in which power laws are observed

Fractional order controller design for SEPIC converter using metaheuristic algorithm

Fractional order proportional, Integral and a derivative controller is a special kind of controller which is used to regulate the output voltage of a class of sepic converter to the desired level. Tuning of fractional Proportional, Integral and Derivative controller (FOPID) is achieved by different metaheuristic algorithm and the optimization performance target is chosen as minimizing the integral square error (ISE). This paper presents a performance analysis of Single Ended Primary Inductance Converter (SEPIC) by time response specifications such as rise time, settling time and steady-state error and further, the results are compared with the controllers designed by Genetic Algorithm (GA), Particle Swarm Optimization (PSO) and Queen Bee based Genetic Algorithm (QBGA). The design and implementation of fractional order controller for a closed loop control of converter is done by utilizing a MATLAB/SIMULINK environment. Results show that QBGA algorithm exhibit better performance as compared to other optimization technique for voltage mode controller in terms of disturbance rejection.

Design and Implementation of Fractional Order Controller for Service Robots

In this paper, the fractional order motion control is designed basing on the Leader IDX service robotic platform, where the implementation of robust fractional order controller is introduced in details. The fractional order PDμ control is analyzed in frequency domain by using an FIR/IIR method. The system model of the motor of Leader I-DX is established in MATLAB so that the influence of μ to the whole control system can be verified, and the comparisons of PD and PDμ controllers are shown as well. Motivated by the better performance of fractional order controllers, a digital implementation of fractional order PDμ controllers using PRONY technique is applied so that the incremental fractional order controllers can be realized. The real experiments on Leader I-DX platform are illustrated to validate the above concepts.

Auto-Tuning and Fractional Order Controller Implementation on Hardware in the Loop System

The paper deals with the design of an auto-tuning fractional order proportional-integrative-derivative controllers and its implementation on hardware in the loop simulator for the real-time control of unknown plants. The proposed procedure can be applied to systems with delay and order greater than one, once specifications on cross-over frequency and phase margin are given. The auto-tuning procedure consists of two phases: the first one dedicated to the identification of the process at the desired cross-over frequency and the second one to determine all the parameters of the fractional order proportional-integrative-derivative controllers. The obtained controller ensures an iso-damping response of the plant. Experimental results are given to confirm the effectiveness of the proposed approach and show that the requirements are totally met for the system to be controlled.

Tuning and implementation methods for fractional-order controllers

Abstract This survey paper presents methods of tuning and implementation of Fractional-Order Controllers (FOC). In the article are presented tuning, auto-tuning and self-tuning methods for the FOC. As the FOC are considered fractional PID controllers, the Commande Robuste d’Ordre Non Entier (CRONE) controller and fractional-order lead-lag compensators. As implementation techniques are described the IIR and FIR filters forms of approximation methods, which can be easily implemented in microprocessor devices such as for example the Programmable Logic Controller (PLC), etc. The possibility for analogue implementation of such kind of controllers is also mentioned. An example of practical implementation of the FOC together with all problems and restrictions are described as well.