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Shantanu Das

Bio: Shantanu Das is an academic researcher from Bhabha Atomic Research Centre. The author has contributed to research in topics: Fractional calculus & PID controller. The author has an hindex of 24, co-authored 152 publications receiving 2925 citations. Previous affiliations of Shantanu Das include University of Chicago & Jadavpur University.


Papers
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Proceedings ArticleDOI
09 Jul 2015
TL;DR: In this article, a generalized approach for the identification of fractional order systems in frequency domain using experimental data is proposed, where the system identification task has been framed as an optimization problem and solved using seeker optimization algorithm.
Abstract: Linear circuits and systems are generally described by traditional differential equations and integer order transfer functions based on the assumption that the dynamics are lumped and time invariant. However, as compared to the conventional integer order calculus, many dynamical systems are better represented by fractional calculus with interaction among the variables modelled by fractional integration and/or fractional differentiation. The present work proposes a generalized approach for the identification of fractional order systems in frequency domain using experimental data. To achieve the same, the system identification task has been framed as an optimization problem and solved using seeker optimization algorithm. The algorithm seeks to attain a set of system parameters for which the deviation between the simulated response of the identified system and experimental data is minimized. The proposed approach has been validated on a set of electrical circuits with varying configuration. The simulation and experimental results reveals that all of the test circuits are better represented by fractional order model, over a wide range of frequency.

7 citations

Journal ArticleDOI
TL;DR: In this paper, a model of a nuclear reactor is developed for a control rod drop scenario involving rapid power reduction in a 500MWe Canadian Deuterium Uranium (CANDU) reactor using AutoRegressive Exogenous (ARX) algorithm.
Abstract: Phase shaping using fractional order (FO) phase shapers has been proposed by many contemporary researchers as a means of producing systems with iso-damped closed loop response due to a stepped variation in input. Such systems, with the closed loop damping remaining invariant to gain changes can be used to produce dead-beat step response with only rise time varying with gain. This technique is used to achieve an active step-back in a Pressurized Heavy Water Reactor (PHWR) where it is desired to change the reactor power to a pre-determined value within a short interval keeping the power undershoot as low as possible. This paper puts forward an approach as an alternative for the present day practice of a passive step-back mechanism where the control rods are allowed to drop during a step-back action by gravity, with release of electromagnetic clutches. The reactor under a step-back condition is identified as a system using practical test data and a suitable Proportional plus Integral plus Derivative (PID) controller is designed for it. Then the combined plant is augmented with a phase shaper to achieve a dead-beat response in terms of power drop. The fact that the identified static gain of the system depends on the initial power level at which a step-back is initiated, makes this application particularly suited for using a FO phase shaper. In this paper, a model of a nuclear reactor is developed for a control rod drop scenario involving rapid power reduction in a 500MWe Canadian Deuterium Uranium (CANDU) reactor using AutoRegressive Exogenous (ARX) algorithm. The system identification and reduced order modeling are developed from practical test data. For closed loop active control of the identified reactor model, the fractional order phase shaper along with a PID controller is shown to perform better than the present Reactor Regulating System (RRS) due to its iso-damped nature.

6 citations

Journal ArticleDOI
TL;DR: In this article, a generalization of the frequency domain robust tuning has been proposed for a family of fractional order (FO) PI/PID controllers, enhanced with two new FO reduced parameter templates which are capable of capturing higher order process dynamics with much better accuracy.
Abstract: Generalization of the frequency domain robust tuning has been proposed in this paper for a family of fractional order (FO) PI/PID controllers. The controller tuning is enhanced with two new FO reduced parameter templates which are capable of capturing higher order process dynamics with much better accuracy. The paper validates the proposed methodology with a standard test-bench of higher order processes to show the relative merits of the family of FO controller structures.

6 citations

Proceedings Article
30 Mar 2012
TL;DR: In this paper, the authors investigated typical behaviors like damped oscillations in fractional order (FO) dynamical systems and used a multilayer feed-forward ANN to predict the optimal pseudo and meta-damping from knowledge of the maximum order or number of terms in the FO dynamical system.
Abstract: This paper investigates typical behaviors like damped oscillations in fractional order (FO) dynamical systems. Such response occurs due to the presence of, what is conceived as, pseudo-damping and meta-damping in some special class of FO systems. Here, approximation of such damped oscillation in FO systems with the conventional notion of integer order damping and time constant has been carried out using Genetic Algorithm (GA). Next, a multilayer feed-forward Artificial Neural Network (ANN) has been trained using the GA based results to predict the optimal pseudo and meta-damping from knowledge of the maximum order or number of terms in the FO dynamical system.

6 citations

Journal ArticleDOI
TL;DR: In this article, the electrical properties of a composite solid polymer electrolyte (SPE) consisting of poly(ethylene oxide), polyvinylidene fluoride, and 35 wt.
Abstract: A solid polymer electrolyte (SPE) film with improved mechanical and thermal stability has drawn significant attention in the field of polymer research due to their technological applications in energy storage devices. We have explored the electrical properties of the blend SPE composed of 20 wt. % poly(ethylene oxide), 80 wt. % polyvinylidene fluoride, and 35 wt. % NH4I by introducing a plasticizer ethylene carbonate (EC). A significant enhancement of electrical conductivity has been found in the composite SPE containing 80 wt. % of EC. We have confirmed the formation of a hydrogen bonding network between the carbonyl group (C=O) of EC and the cations NH4+. Therefore, EC facilitates the new coordination sites via the hydrogen bonding network with the cations NH4+, which eventually leads to the enhancement of conductivity up to a maximum value of 1.2 × 10−4 S/cm at 80 wt. % of EC. The increase in the relative percentage of contact ions over free ions at 80% of EC, as estimated from the FTIR study, is thus intriguing. Therefore, we have proposed an ion transport mechanism based on ion hopping through different coordinating sites mediated by EC. Dielectric relaxation of the composite SPE has been best delineated by a two-parameter Mittag-Leffler function. The exponents obtained from the fit of the experimental decay function with the two-parameter Mittag-Leffler function in the entire time domain are positive and less than one, suggesting non-Debye relaxation in the polymer composite system under investigation.

6 citations


Cited by
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Book ChapterDOI
01 Jan 2015

3,828 citations

01 Nov 2000
TL;DR: In this paper, the authors compared the power density characteristics of ultracapacitors and batteries with respect to the same charge/discharge efficiency, and showed that the battery can achieve energy densities of 10 Wh/kg or higher with a power density of 1.2 kW/kg.
Abstract: The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

2,437 citations

01 Sep 2010

2,148 citations

Book ChapterDOI
11 Dec 2012

1,704 citations

Book ChapterDOI
01 Jan 2014
TL;DR: In this paper, Dzherbashian [Dzh60] defined a function with positive α 1 > 0, α 2 > 0 and real α 1, β 2, β 3, β 4, β 5, β 6, β 7, β 8, β 9, β 10, β 11, β 12, β 13, β 14, β 15, β 16, β 17, β 18, β 20, β 21, β 22, β 24
Abstract: Consider the function defined for \(\alpha _{1},\ \alpha _{2} \in \mathbb{R}\) (α 1 2 +α 2 2 ≠ 0) and \(\beta _{1},\beta _{2} \in \mathbb{C}\) by the series $$\displaystyle{ E_{\alpha _{1},\beta _{1};\alpha _{2},\beta _{2}}(z) \equiv \sum _{k=0}^{\infty } \frac{z^{k}} {\varGamma (\alpha _{1}k +\beta _{1})\varGamma (\alpha _{2}k +\beta _{2})}\ \ (z \in \mathbb{C}). }$$ (6.1.1) Such a function with positive α 1 > 0, α 2 > 0 and real \(\beta _{1},\beta _{2} \in \mathbb{R}\) was introduced by Dzherbashian [Dzh60].

919 citations