Ranjan Maheshwari

An energy management system for a battery ultracapacitor Hybrid Electric Vehicle

In this paper, a simple and efficient power split rule based energy management algorithm is designed for optimal sharing of energy between different energy sources in parallel HEV. This algorithm is simulated in MATLAB for Indian driving cycle (urban drive cycle) and Indian express highway drive cycle. The results indicate that the split of power can allow the engine to operate at its best efficiency and the life of battery can also be improved significantly with the introduction of ultracapacitor by maintaining the battery state of charge (SOC) within desired limits.

Signal-analysis and a heuro-logistic interpretation of multi-lead electrocardiograms

This paper describes a personal computer (PC) based analysis of multi-lead electrocardiograms (ECGs) and their interpretation employing an approach which is a combination of the two basic and conventional approaches, namely the heuristic approach and the logistic approach. The ECG analysis part of the software has been validated using the multi-lead ECGs of the common Standards in quantitative electrocardiography (CSE) database (Data Set 3). Using the spatial velocity approach, the analysis software reliably detects the QRS complexes and then the other component waves (i.e. P & T waves). More than 90% of the fiducial locations of various waves (i.e. P-on. P-off, QRS-on, QRS-off and T-end) estimated by the analysis software using this approach are found to be well within the tolerances recommended by the CSE. A successful attempt has been made to evaluate the parameters of diagnostic importance and interpret the multi-lead ECG analysis results using the heuro-logistic approach. The computerized interpretat...

Maximum power extraction from photo-voltaic power generator with adaptive MPP tracker

Power generation with the help of Photovoltaic (PV) arrays is emphasized increasingly and regarded as an important resource of power energy in the coming years. As the power supplied by PV arrays depends upon the insolation, temperature and array voltage, it is necessary to control the operating point to extract the maximum power from the PV arrays. A number of methods for Maximum Power Point Tracking (MPPT) has been reported in the literature. This paper discusses an adaptive method as well as compares with the conventional fixed step size method, effectively improves the MPPT speed and accuracy simultaneously. An adaptive algorithm and two phase dc-dc Converter is exercised as a MPP tracker. Ripple reduction is possible at input and output side of the converter. Mathematical models of converter are developed using state space averaging technique. The tracking responses of the system operating at the solar array MPP are evaluated. A theoretical analysis of the new algorithm in connection with dc-dc converter is provided and its feasibility is also verified by simulation results.

Improved Method for Characterization of Ultracapacitor by Constant Current Charging

Ultracapacitors are creating new horizons in the field of energy storage systems (ESS). The reason behind the popularity is its unmatched characteristics like very high power density, long cycle life, deep discharge capacity, high efficiency and low ESR. Hence these types of devices can be effectively used in pulse power applications in power system, communication system and hybrid electrical vehicles. Different types of Ultracapacitor models have been analysed and proposed since many years. This paper introduces a simplified three branch dynamic model of Ultracapacitor using constant current charging method .The detailed test procedure for 150 farad and 350 farad ultracapacitors was followed in the laboratory to develop dynamic model of ultracapacitors under charging current of 5A .The model includes R-C branches along with an inductance, EPR (Equivalent Parallel Resistor) and ESR (equivalent series resistance). Ultracapacitor equivalent model is built with the consideration of linear and nonlinear factors, temperature variation & effect of leakage current. The experiment has been implemented with simple laboratory instrument like constant current supply, voltage & current data logger and computer. Computational time required for parameters calculation is minimum & simple compared to other methods followed by different authors. Final results are verified by comparing experimental results with results obtained by simulating the derived equivalent circuit model in MATLAB/Simulink. Finally some applications of ultracapacitor are discussed.

Synchronized pulsed dc-dc converter as maximum power position tracker with wide load and insolation variation for stand alone PV system

This paper investigates the interest focused on employing parallel connected dc-dc converter with high tracking effectiveness under wide variation in environmental conditions (Insolation) and wide load variation. dc-dc converter is an essential part of the stand alone PV system. Paper also presents an approach on how duty cycle for maximum power position (MPP) is adjusted by taking care of varying load conditions and without iterative steps. Synchronized PWM pulses are employed for the converter. High tracking efficiency is achieved with continuous input and inductor current. In this approach, the converter can he utilized in buck as well in boost mode. The PV system simulation was verified and experimental results were in agreement to the presented scheme.

Age, Gender and Racial Effects on Electrocardiographic Parameters

This paper summarizes the effect of age, gender and race on Electrocardiographic parameters. The conduction system and heart muscles get degenerative changes with advancing age so these parameters get changed. The ECG parameters also changes under certain diseases. Then it is essential to know the normal limits of these parameters for diagnostic purpose under the influence of age, gender and race. The automated ECG analysis systems require normal limits of these parameters. The age and gender of the population clearly influencing the normal limits of ECG parameters. However the investigation of the effect of Body Mass Index on cross section of the population is further warranted.

MATLAB-Based Investigation of Multiphase Interleaved Buck-Boost Converter for PV System

A photovoltaic (PV) generator exhibits nonlinear voltage-current characteristics and its maximum power point varies with solar radiation. Analytical investigations of the new family of switching converters based on a parallel connection of 𝑁(=4) identical buck-boost converters employed in PV system are presented. The interleaving strategy ensures that all the converters operate at the same switching frequency. Mathematical models developed using the state-space average technique are presented in this paper. Various steady-state performance expressions are also derived. The present converter system has the advantages of reduced size of the converter, and ripple in the total inductor current. The effectiveness of the four-phase interleaved dc-dc converter combined with PV system is demonstrated through simulations carried out in MATLAB environment.

ECG delineation techniques and applications in Cobra venom interacted patients

ECG signal provides a dynamic assessment of the cardiac activities. To analyze the ECG signal, some innovative ECG delineation techniques alongwith a few known techniques were used to provide the optimum strategy for marking of events. The techniques were applied on 125 records of CSE DS-3 database for calibration and subsequently, on the data acquired from no known-cardiac Cobra bitten patients under strict ethical protocol and medical supervision.