Estimation of Reduced Order Equivalent Circuit Model Parameters of Batteries from Noisy Current and Voltage Measurements

Identification of reduced order equivalent circuit battery model from current and voltage measurements allows modeling, classification and monitoring of batteries, and these tasks are very essential for battery management systems. This study presents a theoretical study to investigate performance of computer-aided identification of the reduced order equivalent circuit battery model from noisy current and voltage measurement data. The battery model is expressed in the form of fractional order differential equation and time domain numerical solution of this model is numerically calculated according to Grünwald-Letnikov definition of fractional-order derivative. Paper demonstrates an application of this numerical solution so that it can fit noisy current and voltage measurement data, and thus parameters of the equivalent circuit battery model can be estimated. Particle swarm optimization (PSO) method is used to solve this model fitting problem. Performance of the parameter estimation method is investigated for various noise levels of the synthetically generated current and voltage profiles

Transient Analysis of Double Layer Metal-Gas-Dielectric-Metal DBD Cell

The investigation of Dielectric Barrier Discharges (DBD) in the absence of breakdown has significance in the perspective of the technological processes based on discharge phenomena and high voltage techniques. This study carries out transient analyses for the temporal evolution of electrical field, space charge density, polarization current while charging experimental Metal-Gas-Dielectric-Metal (MGDM) DBD cell. For these proposes, a theoretical model based on current continuity and two-layer polarization mechanism is developed for the investigation of an experimental MGDM electrodes system. In the steady state, the model obeys energy conservation law. Analysis results are discussed on the basis of experimental current measurements to explain pulsed DBD curren

HYBRID APPROXIMATION METHOD FOR TIME RESPONSE IMPROVEMENT OF CFE BASED APPROXIMATE FRACTIONAL ORDER DERIVATIVE MODELS BY USING GRADIENT DESCENT ALGORITHM

Due to its high computational complexity, fractional order (FO) derivative operators have been widely implemented by using rational transfer function approximation methods. Since these methods commonly utilize frequency domain approximation techniques, their time responses may not be prominent for time-domain solutions. Therefore, time response improvements for the approximate FO derivative models can contribute to real-world performance of FO applications. Recent works address the hybrid use of popular frequency-domain approximation methods and time-domain approximation methods to deal with time response performance problems. In this context, this study presents a hybrid approach that implements Continued Fraction Expansion (CFE) method as frequency domain approximation and applies the gradient descent optimization (GDO) for step response improvement of the CFE-based approximate model of FO derivative operators. It was observed that GDO can fine-tune coefficients of CFE-based rational transfer function models, and this hybrid use can significantly improve step and impulse responses of CFE-based approximate models of derivative operators. Besides, we demonstrate analog circuit realization of this optimized transfer function model of the FO derivative element according to the sum of low pass active filters in Multisim and Matlab simulation environments. Performance improvements of hybrid CFE-GDO approximation method were demonstrated in comparison with the stand-alone CFE method

A note on applications of time-domain solution of Cole permittivity models

The complex dielectric permittivity is an important parameter for characterization of electrical properties of dielectric materials. Experimental studies demonstrated that Cole models of dielectric permittivity can provide a better fitting to the experimental data because of allowing for fractional-order frequency dependence. This study aims to investigate physical interpretation of time domain solutions of Cole permittivity models. For this purpose, impulse responses of Cole-Cole model and Davidson-Cole model are expressed in Mittag-Leffler function form by using inverse Laplace transform. The impulse responses of these models are decomposed into impulsive and dispersive components, and the relations of these components with relaxation mechanism of dielectric materials are discussed. By considering impulse response solution of Cole-Cole models, a fractional order dynamic capacitance model is introduced for time domain equivalent circuit modeling of dielectric materials. Moreover, transient properties of electromagnetic wave penetration to dielectric materials are analyzed according to impulse response solution of Cole-Cole model. To illustrate applications of proposed time domain permittivity solutions, the Cole-Cole model of ethyl-acetate liquids was also studied and results are presented. (C) 2017 Elsevier GmbH. All rights reserved

Adaptive Control of Nonlinear TRMS Model by Using Gradient Descent Optimizers

International Conference on Artificial Intelligence and Data Processing (IDAP) -- SEP 28-30, 2018 -- Inonu Univ, Malatya, TURKEYThis study demonstrates an application of direct gradient descent control for adaptively control of a nonlinear stable system models. The approach is based on utilization of gradient descent optimization techniques for the synthesis of control signals to control a specific plant model. In a former work, gradient descent optimizers were designed by considering a first degree instant input-output relation model assumption of the controlled system and this can allow model independent adaptive control of a class of plant models that can approximate to first order stable plant dynamics. The current study is an extension of this scheme for the purpose of nonlinear adaptive control. Here, we consider a higher degree polynomial assumption of instant input-output relations of the controlled system to obtain gradient descent optimizers that can be applied for adaptive control of a class of nonlinear systems. For evaluation of control performance of gradient descent optimizers, it is applied for the control of nonlinear TRMS model and the results are compared with performance of conventional PID control.Inonu Univ, Comp Sci Dept, IEEE Turkey Sect, Anatolian Sc

Modeling and analysis of dielectric materials by using gradient-descent optimization method

This study presents a numerical method based on parallel RC equivalent circuit model fitting methodology for analysis and modeling of dielectric materials. The proposed method employs gradient-descent optimization method (GDOM) to estimate parallel RC equivalent circuit model from current waveforms by minimizing sum of squared difference (SSD) error. Estimation of parallel RC equivalent circuit parameters from measured current waveforms provides a useful tool for identification, simulation and analysis of dielectric materials. Moreover, applications of the proposed method for time and frequency analyses of dielectric materials are demonstrated numerically. Numerical simulations were presented to discuss efficiency of the proposed method for modeling, analysis and monitoring of insulator materials

Sigmoid Based PID Controller Implementation for Rotor Control

European Control Conference (ECC) -- JUL 15-17, 2015 -- Linz, AUSTRIAThis paper presents a sigmoid based variable coefficient PID (SBVC-PID) controller design for Twin Rotor MIMO System (TRMS). The proposed SBVC-PID controller dynamically changes controller coefficients according to a modified sigmoid function of the error signal. The modified sigmoid function is used to limit variability of PID controller coefficients in a predefined range. In the proposed method, each parameters of PID, namely k(P), k(i) and k(d), alter between predefined upper and lower bounds. A modified sigmoid function adjusted by a transition coefficient is used to alter each of the PID parameters between these bound limits. The variable coefficients of SBVC-PID maintain a hypercube in k(P), k(i) and k(d). parameter space satisfying robust stability of the system. Well-known Kharitonov polynomials are used to ensure that the SBVC-PID coefficient alteration takes place in the robust stability intervals. Due to dynamically change of PID coefficients depending on magnitude of error signal, the control performance can be improved compared to conventional PID control. Performance of SBVC-PID controller is demonstrated via theoretical examples and TRMS rotor control simulations

An effective analog circuit design of approximate fractional-order derivative models of M-SBL fitting method

There is a growing interest in fractional calculus and Fractional Order (FO) system modeling in many fields of science and engineering. Utilization of FO models in real-world applications requires practical realization of FO elements. This study performs an analog circuit realization of approximate FO derivative models based on Modified Stability Boundary Locus (M-SBL) fitting method. This study demonstrates a low-cost and accurate analog circuit implementation of M-SBL fitting based approximate model of FO derivative elements for industrial electronics. For this purpose, a 4th order approximate derivative transfer function model of the M-SBL method is decomposed into the sum of first order low-pass filters form by using Partial Fraction Expansion (PFE) method, and the analog circuit design of the approximate FO derivative model is performed. Firstly, by using the final value theorem, authors theoretically show that the time response of the sum of first order low-pass filter form can converge to the time response of fractional order derivative operators. Then, the approximation performance of proposed FO derivative circuit design is validated for various input waveforms such as sinusoidal, square and sawtooth waveforms via Multisim simulations. Results indicate an accurate realization of the FO derivative in time response (an RMSE of 0.0241). The derivative circuit realization of the M-SBL fitting model in the form of the sum of first order low pass filters can yield a better time response approximation performance compared to the Continued Fraction Expansion (CFE) based ladder network realization of the approximate derivative circuit. © 2021 Karabuk Universit

Multi-loop Model Reference Adaptive PID Control for Fault-Tolerance

This study demonstrates an application of multi-loop Model Reference Adaptive Control (MRAC) structure for enhancement of fault tolerance performance of closed-loop PID control systems. The presented multi-loop MRAC-PID control structure can be used to transform a conventional PID control system to an adaptive control system by combining an outer adaptation loop. This study shows that the proposed control structure can improve fault tolerance and fault detection performance of the existing closed-loop PID control systems without modifying any coefficients of PID controllers, and this asset is very useful for increasing robust control performance of the existing industrial control systems. This advantage originates from the reference input shaping technique that is implemented to combine adaptation and control loops. Numerical and experimental studies are presented to illustrate an application of the MRAC-PID control structure for rotor control applications