Faculty Publications
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Publications by NITK Faculty
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Item Energy storage system in microgrid(wiley, 2022) Ahmad, M.W.; Raushan, R.The energy storage systems (ESS) integrated microgrid have grown attention and acceptance because it has power reliability and sustainable energy utilization capability. Several ESS has been introduced with significant characteristics such as performance, size, life cycle, charging/discharging, safety, reliability, capacity, and cost. This chapter comprehensively reviews the types of ESS technologies, configurations, classifications, features, energy conversion, life cycle, and advantages and disadvantages. Moreover, the power electronics converter interfacing the microgrid has also been briefly studied. The present review critically demonstrates the interfacing circuits of ESS to microgrids. The mathematical modeling of bidirectional DC-DC converter interfacing the ESS to DC microgrid is presented developed. Moreover, the modeling and control of VSI interfacing the BESS to a three-phase grid is also demonstrated. The simulation model for both systems is also developed in MATLAB-Simulink. A critical review of the obtained simulation results is presented to show the ability of the DC-DC converter and VSI system for charging the BESS and delivering the power to the microgrid as per the requirement assigned by the higher-level controller of the microgrid. © 2022 Scrivener Publishing LLC. All rights reserved.Item Transformerless grid-connected inverter for PV integration(Institution of Engineering and Technology, 2022) Muhammad Ramees, M.K.P.; Ahmad, M.W.; Aasim, u.[No abstract available]Item Particle Swarm Optimization based Maximum Power Point Tracking Technique for Solar PV System under Partially Shaded conditions(Institute of Electrical and Electronics Engineers Inc., 2021) Naseem, M.; Husain, M.A.; Kumar, J.; Ahmad, M.W.; Minai, A.F.; Khan, A.A.To attain peak power from a PV source, the maximum power point tracking (MPPT) approach is frequently used. The MPP of a photovoltaic (PV) system is not constant since its output characteristics are dependent on numerous parameters. Partial shading causes significant changes in the PV system's attributes, and it often shows several local maxima as well as global maxima. Due to the development of local maxima, traditional MPPT methods fail in partial shade situations. Due to partial shade, solar systems frequently have hot spots, which not only disrupt system yield power but also compromise the system's dependability and safety. Due to the existence of many peaks in the P-V curve under partial shade, the traditional MPPT becomes stuck in local maxima rather than the global peak. As a result, sophisticated MPPT systems are required to accurately track the real peak power despite changing temperature and irradiation circumstances. To accomplish this, this study proposes a tracking scheme based on particle swarm optimization (PSO). The suggested MPPT is simple, versatile, precise, and economical, and it can track global MPP even when partially shaded. The proposed algorithm's performance is examined in MATLAB Simulink to test the effectiveness of the recommended MPPT technique. © 2021 IEEE.Item A Technological Research on Electric Vehicles Charging Approaches and Optimization Methods(Institute of Electrical and Electronics Engineers Inc., 2022) Vani, B.V.; Kishan, D.; Ahmad, M.W.; Hanumanthakari, S.; Reddy, B.N.K.In Present day various countries all throughout the world have taken on Electric Vehicles (EVs) to diminish air pollution and fuel consumption. In coming years, Electric Vehicles are bound to become crucial in the transport field. Subsequently, the charging approaches are in the same line. This paper presents an outline of the current and proposed EV charging approaches and optimization methods. Especially the various EV charging methods like battery exchange, conductive charging and wireless charging are presented. Next, some of the EV charging/discharging optimization methods are examined. On the basis of investigation, a few proposals are put forward for future research. © 2022 IEEE.Item Sliding Mode Observer Based Open-Circuit Fault Detection in the HERIC PV Inverter(Institute of Electrical and Electronics Engineers Inc., 2022) Muhammad Ramees, M.K.P.; Ahmad, M.W.; Brahmendra Yadav Gorla, N.B.Y.Grid connected transformer-less Photovoltaic inverter known as highly efficient and reliable inverter concept (HERIC) is derived from the industrial-standard full-bridge topology with two additional switches on ac side. This paper presents a detection and localization method for open-circuit (OC) failures in the semiconductor switches of HERIC inverter. Fault detection based on sliding mode observer (SMO) is proposed for the ac bypass switches and an average current estimator is used to detect failures in the main switches of full bridge inverter. Two parallel SMOs are developed based on the state space model of the converter under different OC fault conditions in ac bypass leg. Observed grid current and measured grid current are used to obtain the residual which determines the location of OC fault in the inverter. The key advantage of the proposed method is that it does not require additional sensors for fault diagnosis which will improve the system robustness. Efficacy and reliability of the proposed method is validated using simulation studies. © 2022 IEEE.Item Dual Output Symmetrical Voltage Cancellation Controlled Full Bridge Resonant LED Driver(Institute of Electrical and Electronics Engineers Inc., 2023) Ponduru, R.R.; Kishan, D.; Ahmad, M.W.This paper proposes a simultaneous controlled dual output full-bridge converter for LED lighting systems. Two LED lamps are powered using a full-bridge. The devices in full-bridge converter are switched at zero voltage using LC resonant circuit. Therefore, switching transition power losses are minimized which increases the LED driver efficiency. An inductor is connected in series with each LED lamp to reduce ripple current. Thus, the use of electrolytic capacitor can be eliminated. This feature increases lifespan of proposed resonant LED driver. Symmetrical Voltage Cancellation control is designed for both regulation and dimming operation. Numerical simulations are carried out to validate the performance of the proposed LED converter circuit configuration. © 2023 IEEE.Item Open-Circuit Fault Detection and Identification in Neutral Point Clamped Inverter via Sliding Mode Observers(Institute of Electrical and Electronics Engineers Inc., 2023) Muhammad Ramees, M.K.P.; Saywan, Y.A.; Ahmad, M.W.Neutral point clamped (NPC) inverters offer a range of advantages, including reduced switching loss, decreased harmonic distortion in output voltage, minimized emissions impact, and improved efficiency. However, System reliability becomes a significant concern in NPC inverters due to their higher susceptibility to failures due to the increased number of power electronic switches in comparison to conventional two-level inverters. Power electronic switch faults, particularly open circuit faults, can potentially lead to cascaded failures within the system. To address this issue a sliding mode observer-based method is proposed in this paper. The effectiveness of the method is evaluated through detailed simulations using MATLAB/Simulink. The results demonstrate the capability of the sliding mode observer in accurately detecting open switch faults, contributing to enhanced fault diagnosis and improved reliability of NPC inverters. © 2023 IEEE.Item Design of a Multi-Mode DC-DC Converter for High-Power Wireless Charging of Electric Vehicles(Institute of Electrical and Electronics Engineers Inc., 2024) Kishan, D.; Mallikarjuna, B.; Ahmad, M.W.; Chub, A.The design of high-power wireless power transfer (WPT) systems has been the subject of substantial research due to the increasing demand for fast, efficient, and effective battery charging methods for electric vehicle (EV) customers. This paper proposes a DC-DC converter capable of operating in three distinct modes. It incorporates an H6-Bridge inverter, which can be configured as half bridge-half bridge (HB-HB), half bridge-full bridge (HB-FB), and full bridge-full bridge (FB-FB), and is connected through LCC-Series networks to a dedicated H6-Bridge configuration. This innovative design enables efficient charging of EVs with battery voltage classes ranging from 400V to 800V without affecting the current ratings of the converter's components. Furthermore, the paper presents an analysis of an equivalent circuit WPT system for battery packs with output voltages of 400V, 600V, and 800V. To validate its effectiveness, a 7.2 kW power converter with a 600V input and a variable output range from 400V to 800V was simulated, achieving an impressive maximum efficiency of 94.2% across a wide spectrum of output voltages. © 2024 IEEE.Item A Fault Diagnosis and Postfault Reconfiguration Scheme for Interleaved Boost Converter in PV-Based System(Institute of Electrical and Electronics Engineers Inc., 2021) Ahmad, M.W.; Brahmendra Yadav Gorla, N.B.Y.; Malik, H.; Panda, S.K.To utilize the solar photovoltaic (PV) energy efficiently, dc-dc converters are widely used in both grid-connected and stand-alone systems. Among the various topologies, interleaved dc-dc boost converter offers the benefit of modularity, high power density, and high efficiency along with reduced input current ripple to the PV panel, thereby improving its power extraction efficiency. Open-circuit faults in any of the semiconductor switches of interleaved boost converter could lead to unequal loading on the healthy phases and increase in ripple current that reduces the extraction efficiency of the PV system. To address this issue, a new fault detection and localization scheme is proposed in this article. The proposed scheme utilizes the switching-frequency-based harmonic component for fault detection and localization. Once the fault is localized, a postfault restoration and control strategy is also proposed to ensure equal current sharing among the remaining healthy modules within their maximum current rating and minimize the input current ripple in the PV panel. Detailed simulations are carried out to show the effectiveness of the proposed approach. A laboratory prototype of the interleaved converter is built to validate the proposed approach and experimental test results are provided. © 1986-2012 IEEE.Item Noninvasive Model-Based Open-Circuit Switch Fault Detection of AC-Bypass Leg Switches in Transformerless PV Inverter(Institute of Electrical and Electronics Engineers Inc., 2021) Ahmad, M.W.; Brahmendra Yadav Gorla, N.B.Y.; Malik, H.; Panda, S.K.Transformerless inverters are being used for integrating photovoltaic (PV) sources into the grid. Highly efficient and reliable inverter concept (HERIC) inverter is one such topology, which is derived from an H-bridge by adding a bypass leg on the ac side using two back-to-back insulated gate bipolar transistors (IGBTs). Open-circuit fault in the bypass leg would result in conduction of current through antiparallel diodes of the main switches of the inverter, effectively making the inverter operate in bipolar mode. As a result of the fault, there would not be an issue of leakage current, and the operation would continue at the expense of increased conduction losses and dc-offset in the grid current. This article proposes an online noninvasive model-based technique to detect switch faults in the bypass leg of the HERIC inverter. The grid current at the peak of the carrier signal is predicted based on the measured grid current at the start of the zero states. By comparing the estimated and measured grid currents at the peak of the carrier signal, the faulty switch in the bypass leg is localized. Once the fault is localized, the inverter's modulation scheme is changed to conventional bipolar mode to improve the performance of the converter during the post-fault stage. A detailed simulation study is carried out to verify the effectiveness of the proposed approach. Experimental tests on the prototype converter show that the proposed algorithm can reliably detect the open-circuit fault in switches of the bypass leg, and once a fault is detected, the algorithm would change the modulation scheme to bipolar mode to minimize the inverter loss and dc-offset in the grid current. © 2013 IEEE.