Yogesh V. Hote

Load Frequency Control in Power Systems via Internal Model Control Scheme and Model-Order Reduction

The large-scale power systems are liable to performance deterioration due to the presence of sudden small load perturbations, parameter uncertainties, structural variations, etc. Due to this, modern control aspects are extremely important in load frequency control (LFC) design of power systems. In this paper, the LFC problem is illustrated as a typical disturbance rejection as well as large-scale system control problem. For this purpose, simple approach to LFC design for the power systems having parameter uncertainty and load disturbance is proposed. The approach is based on two-degree-of-freedom, internal model control (IMC) scheme, which unifies the concept of model-order reduction like Routh and Padé approximations, and modified IMC filter design, recently developed by Liu and Gao [24]. The beauty of this paper is that in place of taking the full-order system for internal-model of IMC, a lower-order, i.e., second-order reduced system model, has been considered. This scheme achieves improved closed-loop system performance to counteract load disturbances. The proposed approach is simulated in MATLAB environment for a single-area power system consisting of single generating unit with a non-reheated turbine to highlight the efficiency and efficacy in terms of robustness and optimality.

Advances in Internal Model Control Technique: A Review and Future Prospects

Abstract The current study endeavors to put together evolution, developments, and future prospects of internal model control strategy. Due efforts have been made to include all the techniques and philosophies used to that end. The brief account of the most recent techniques for near optimal and robust control has been provided along with a summary of conventional control schemes. At the same time, more emphasis is given on the issues in IMC design for single-input, single-output systems, like quantitative filter selection and tuning guidelines, modified structures, and related aspects of contemporary research developments. A set of references of all concerned papers, and a brief summary in them is provided. This paper also presents the results of these techniques as provided in the respective references. Illustrative example is given to show the effectiveness and the merits of the IMC based various forms.

Robust Stability Analysis of the PWM Push-Pull DC–DC Converter

In this letter, robust stability analysis of the closed-loop pulsewidth modulated push-pull DC-DC converter with a state feedback control is presented using simple frequency-domain conditions based on the Hermite-Biehler theorem. The proposed technique for checking robust stability is efficient, since there is no need to calculate all the uncertain values of the system and hence no need to formulate and test all four Kharitonov polynomials.

An efficient approach for face recognition based on common eigenvalues

In this paper, a simple technique is proposed for face recognition among many human faces. It is based on the polynomial coefficients, covariance matrix and algorithm on common eigenvalues. The main advantage of the proposed approach is that the identification of similarity between human faces is carried out without computing actual eigenvalues and eigenvectors. A symmetric matrix is calculated using the polynomial coefficients-based companion matrices of two compared images. The nullity of a calculated symmetric matrix is used as similarity measure for face recognition. The value of nullity is very small for dissimilar images and distinctly large for similar face images. The feasibility of the propose approach is demonstrated on three face databases, i.e., the ORL database, the Yale database B and the FERET database. Experimental results have shown the effectiveness of the proposed approach for feature extraction and classification of the face images having large variation in pose and illumination.

Gerschgorin Theorem and its Applications in Control System Problems

In this paper, we have presented application of Gerschgorin theorem in relative stability analysis of a system represented by a polynomial. We have also presented the applications of Gerschgorin Theorem in reduced order modeling by identifying time scales and stabilization for linear time invariant systems.

Design of PID Controller for Unstable System

This paper describes the design of a PID Controller for an unstable electronic circuit using various tuning techniques like Ziegler Nichols (Z-N), Chien Hrones Reswick (CHR), and Genetic Algorithm (GA). Further, comparison of various performance parameters for these techniques has been done. The results are verified in MATLAB environment.

Fractional-Order PI Controller with Specific Gain–Phase Margin for MABP Control

ABSTRACT Mean arterial blood pressure (MABP) is one of the most important clinical parameters which is required to be controlled very accurately. Therefore, it is very essential to have an efficient and precise control strategy for regulating the MABP in various clinical conditions, which can work well in uncertain operating environment, and also show good disturbance rejection. Although the fractional-order control scheme has evolved as a strong control strategy in recent times, the design techniques available in the literature are mathematically very complex and hence limit the usage of fractional-order controllers. Moreover, it is observed that the gain and phase margin based techniques that exist in the literature for integer order systems are not completely applicable to the fractional-order systems. Therefore, in this paper, a design scheme is proposed for fractional-order PI controller based on gain and phase margins for controlling the MABP. The beauty of the proposed technique is that the controller designed is found to give better disturbance rejection than the conventional proportional integral (PI) or the IMC-PI controllers for nominal as well as the sensitive and insensitive patients. Thus, the technique proposed here gives the dual advantage of computational simplicity as well as robust controller performance.

Design of PID controller for inverted pendulum using stability boundary locus

In this paper, PID controller has been designed for cart inverted pendulum system. The proposed approach is based on newly developed concept of stability boundary locus. The main advantage of this approach is that the cart oscillations has been minimized and angle of pendulum is stabilizes with minimum settling time. The results are also compared with the recently proposed approach of PID and LQR controller. The results are simulated in Matlab environment.

Adaptive Policy for Load Frequency Control

Till date, various load frequency control (LFC) schemes have been reported and every scheme has its own way of disturbance rejection capability. Utilizing some of them together may bring improved performance. Keeping this fact in mind, an adaptive control policy is proposed in this letter. The policy incorporates the concept of enhancing and lowering the controller activity by assigning them weights at every instance throughout the operation. Thus, there is no need to go for a new LFC scheme until required, and a guaranteed improved performance would be achieved. Different case studies including single and multi-area power systems have been conducted to verify the accuracy and efficiency of the proposed method.

Fractional IMC design for fractional order gas turbine model

The gas turbine is an extremely important component for the automotive and aviation industry. It works by converting the energy obtained by fuel combustion into some form of mechanical power. Therefore, controlling the input fuel going to the turbine is an important aspect of the gas turbine system. Therefore, an efficient controller design is required which can control the rate of the fuel being fed to the turbine. It is observed that the Internal Model Control (EVIC) based controller design scheme is quite popular due to its robust performance and mathematical simplicity. This type of controllers are very successfully being used in integer order systems. However, it is seen that the system behavior represented by the fractional order mathematical model is more close to the real life dynamics, especially for large complicated systems. Therefore, in this paper a fractional order model of the gas turbine plant is considered and a fractional order EVIC controller is designed. It is observed that the controller designed using the proposed technique gives better results than the other fractional EVIC controllers available in the literature. The performance of the proposed controller is compared to the existing fractional order EVIC techniques using the integral error criterion.