Browsing by Author "Ahmad, M.W."

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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.
A New Single-Source Nine-Level Quadruple Boost Inverter (NQBI) for PV Application
(Institute of Electrical and Electronics Engineers Inc., 2022) Singh, A.K.; Raushan, R.; Mandal, R.K.; Ahmad, M.W.
Multi-level inverters (MLIs) with switched capacitors are becoming popular due to their utilization in AC high-voltage applications as well as in the field of renewable energy. To achieve the required magnitude of output voltage, the switched capacitor (SC) technique employs a lesser number of DC sources in accordance with the voltage across the capacitor. Designing an efficient high-gain MLI with fewer sources and switches needs a rigorous effort. This paper introduces a prototype of a nine-level quadruple boost inverter (NQBI) topology powered by one solar photo-voltaic source using fewer capacitors, switches, and diodes when compared to the other SC-MLIs topology. The suggested NQB inverter produces nine levels of voltage in its output by efficiently balancing the voltages of the two capacitors. The various SC-MLIs are compared in order to highlight the benefits and drawbacks of the proposed nine-level quadruple boost inverter (NQBI) topology. To validate the efficacy of the proposed solar photovoltaic based NQBI without grid connection, detailed experimental results are presented in a laboratory setting under various test conditions. © 2013 IEEE.
A Novel Single Source Bridgeless Nine-Level Switched-Capacitor-Based Quadruple Boost Inverter With Reduced Voltage Stress
(Institute of Electrical and Electronics Engineers Inc., 2024) Kumar, D.; Raushan, R.; Ahmad, M.W.; Dutta, S.
The attractiveness of switched capacitor multilevel inverters (SCMLIs) stems from their ability to operate without transformers, providing voltage-boosting capabilities, inherent capacitors' voltage balancing ability, and reduced electromagnetic interference. Recent developments in SCMLI structures make it a compelling choice among various converters for diverse applications. The evolution of these topologies is primarily influenced by factors such as the number of output voltage levels, overall voltage gain, and the simultaneous reduction of component counts and stresses on devices. To address these issues further, a novel bridgeless common neutral switched capacitor multilevel inverter has been proposed in this article. The maximum voltage stress on the devices is just half of the peak output voltage, and the total standing voltage is also lower in this inverter. It has quadruple voltage gain and inherent voltage balancing of the switched capacitors. Additionally, it can operate under various loads and modulation indexes. Moreover, the proposed inverter's leakage current can be almost zero due to the presence of the common ground (CG) feature. The nearest level pulse width control technique has been implemented to operate the proposed inverter. Comparative analysis was carried out to show the advantages of the inverter. Further, a hardware prototype of the experimental setup has been developed, and results have been analyzed and discussed to strengthen the performance of the proposed inverter. © 2013 IEEE.
A Reduced Component Count Self-Balance Quadruple Boost Seventeen-Level Switched Capacitor Inverter
(Institute of Electrical and Electronics Engineers Inc., 2024) Ahmed, S.; Raushan, R.; Ahmad, M.W.
A switched capacitor multilevel inverter (SCMLI) enables high-quality output voltage waveforms for various industrial and renewable energy applications. SCMLI uses a combination of capacitors and switches to generate multiple voltage levels from a single dc source, thereby reducing the overall cost and size of the system. This article proposes a novel configuration of a 17-level SCMLI. The proposed converter can boost four times the input voltage by exploiting the series-parallel connection of capacitors with the dc voltage source. With simple pulsewidth modulated (PWM) control, the capacitor voltages are inherently balanced under different loading conditions. Furthermore, for 11 switches, only seven independent switching signals are required. Loss analysis reveals that the proposed SCMLI has significantly reduced conduction losses, capacitor ripple voltage, voltage stress, and cost function (CF) when compared with other topologies available in the literature. Finally, the simulation results are obtained at different loads and modulation indexes. The results are experimentally validated with a scaled-down laboratory prototype. © 2024 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.
A Review of Open-Circuit Switch Fault Diagnostic Methods for Neutral Point Clamped Inverter
(MDPI, 2022) Mullali Kunnontakath Puthiyapurayil, M.R.; Nadir Nasirudeen, M.; Saywan, Y.A.; Ahmad, M.W.; Malik, H.
Due to numerous advantages, a neutral point clamped (NPC) inverter is a preferred choice for high-power applications and renewable technology. The reliability of the NPC inverter is a major concerning factor during the assessment of system performance as power semiconductor switches are vulnerable to abnormal conditions. Open-circuit (OC) switch faults are not as dangerous as short circuit (SC) faults but eventually have enough potential to cause cascaded failure to other components in the system and thus need to be supervised carefully. The OC faults result in a distortion of voltage and current signals in the NPC converter. Based on these signals, over the past few years, many efforts have been made to identify and localize the OC switch fault to the switch level in the NPC topology. In this paper, a review of different OC switch fault diagnostic methods is provided. Starting from the NPC inverter operation under healthy and faulty conditions, the various possible and unavailable switching states along with the deviation in pole voltage under different switch fault conditions is discussed. Then, based on the approach used for system-based fault detection, the OC fault detection methods are classified. The various OC methods are further discussed on the basis of signal, i.e., current, voltage or a combination of both signals used as a signature for fault detection. Emphasis is given to the principle involved, diagnostic variables utilized, the implementation approach and the diagnostic time required. Finally, the approaches are tabulated so as to provide a quick reference for NPC fault diagnostics. © 2022 by the authors.
A Robust Open Circuit Fault Detection and Localization Scheme for HERIC PV Inverter
(Institute of Electrical and Electronics Engineers Inc., 2025) Muhammed Ramees, M.M.K.P.; Ahmad, M.W.
Transformerless inverters are widely used to integrate the photovoltaic (PV) source into the distributed generation system. Within the converter, an open-circuit (OC) switch fault may lead to the partial or total failure of the converter. To address this issue, a new technique for detecting and localizing OC switch faults based on pole-to-pole voltage (voltage measured across the inverter output terminals) is proposed. The proposed variables for fault detection and localization (FDL) are continuously generated with every sampled pole-to-pole voltage and are compared with threshold values which are immune to parameter variation. As a result, OC is detected and located within a switching cycle for the ac side bypass switches. For localizing the OC fault in the H-bridge, the converter is reconfigured once the fault in the H-bridge switch is detected using pole-topole voltage. The input voltage required for the maximum power point tracking (MPPT) is estimated from the voltage measured with the new sensor arrangement for pole-to-pole voltage measurement. This makes the number of sensors the same as in a conventional converter. The viability and effectiveness of this approach are demonstrated through simulation studies on the highly efficient and reliable inverter concept (HERIC) inverter, a popular transformerless inverter topology. Additionally, a laboratory prototype is developed to validate the practical applicability of the method. © 1982-2012 IEEE.
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. Â© 2022 IEEE.
An efficient battery swapping and charging mechanism for electric vehicles using bat algorithm
(Elsevier Ltd, 2024) Vani, B.V.; Kishan, D.; Ahmad, M.W.; Naresh Kumar Reddy, B.N.K.
The recent surge in electric vehicle (EV) adoption has presented various challenges, notably in the charging and discharging processes of EV batteries, each characterized by unique traits. While conventional charging stations remain popular, battery swap stations (BSS) offer a compelling alternative, addressing issues like prolonged waiting times and potential battery degradation from fast charging. BSS, with its extensive array of battery systems, ensures efficient services for EVs. However, meticulous planning for the charging and discharging operations is imperative for both BSS and the overall grid to guarantee optimal functionality. This paper proposes an efficient approach to enhance the efficiency of battery swapping and charging mechanisms (BSCM) for electric vehicles, leveraging the bat algorithm. The BSCM is conceived as a system that incorporates both the battery swapping mechanism (BSM) and the battery charging mechanism (BCM). The key contribution lies in designing an effective BSCM where the BSM functions as a manager, handling battery swapping requests from EV users, while the BCM acts as a supporter, interfacing with the grid to regulate battery charging and discharging power. To efficiently address the mixed-integer nonlinear program (MINLP) inherent in this system, a Bat algorithm is developed. The results clearly demonstrate the effectiveness of the proposed algorithm in efficiently addressing large-scale problems, producing solutions that closely approach optimality. It promptly achieves a substantial reduction in battery swapping energy by 30% and 24%, respectively, and significantly enhances charging station utilization by 25% and 21% compared to the LSTM-Based Rolling Horizon Approach and Bilevel Optimization Approach. Additionally, the algorithm showcases remarkable improvements in battery swapping performance, boasting a 25% and 19% enhancement, and noteworthy increases in charging station utilization by 20% and 17% compared to the aforementioned approaches. This enhancement in the energy exchange with grid and regulation contributes to the overall efficiency and sustainability of electric vehicle operations. © 2024 Elsevier Ltd
An Inductorless Triple Boost 13-Level Switched Capacitor Inverter with Reduced Ripple Current
(Institute of Electrical and Electronics Engineers Inc., 2024) Ahmed, M.S.; Raushan, R.; Ahmad, M.W.
Switched capacitor (SC) multilevel inverter (SCMLI) is a promising alternative to traditional voltage source inverters for industrial and renewable energy applications. In SCMLI, capacitors are used in a specific sequence during charging and discharging either in parallel or series with the source for level generation. During the charging period of the capacitor, a large ripple current is generated. This ripple may cause an increase in the peak current and ripple voltage of the capacitors. The reliability and life expectancy of the inverter can be severely affected by this ripple current of the capacitor. This article proposes an inductorless self-balance single-phase 13-level inverter with triple boosting capability. It aims to reduce the ripple current in both the source and capacitors by arranging the switching sequence in a particular fashion to implement a partial charging technique in the capacitors. Furthermore, it results in better efficiency and reduced current stress without the need for any source inductance or a complicated control algorithm. The performance of the proposed inverter is verified through its laboratory prototype under dynamic load conditions and varying modulation indexes. © 1986-2012 IEEE.
Bat Optimization Model for Electric Vehicle Route Optimization Under Time-of-Use Electricity Pricing
(Springer, 2023) Vani, B.; Kishan, D.; Ahmad, M.W.; Naresh Kumar Reddy, B.
In the framework of fuel reduction and energy conservation, the electric vehicles (EV’s) has been identified as a promising option in contrast to fuel-driven vehicles. EV’s battery limits to require visiting a greater number of times to the recharging stations, which must be viewed as in the route planning to keep away from inefficient vehicle routes with lengthy diversions. These problems have to consider, we propose an Efficient Electric Vehicle Route Optimization with Time-of-Use Electricity Pricing using Bat algorithm. Which can reduce the used vehicles as well as electricity-cost and total travel distance. Additionally, functional model and collective models are used to minimize the objectives: distance and cost. The computational assessment in light of the notable benchmarking test instances exhibits, proposed optimization algorithm electricity cost conservation on average 12.17% with Learnable Partheno-Genetic Algorithm (Yang et al. in IEEE Trans Smart Grid 6:657–666, 2015) 8.45% with VNS/TS Algorithm (Lin et al. in Trans Res Part-C 130:103285, 2021) and 5.15% with Mixed Integer Programming model (Ham and Park in IEEE Access 9:37220–37228, 2021). © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Design and Implementation of Different Drive Topologies for Control of Induction Motor for Electric Vehicle Application
(River Publishers, 2022) Husain, M.A.; Rajput, R.; Gupta, M.K.; Tabrez, M.; Ahmad, M.W.; Ilahi Bakhsh, F.I.
To improve driving range in Electric vehicles (EV), parallel-series connection of battery cells is a necessity. Supressing the circulating current in the battery board of parallel connected battery strings helps improve the lifespan of the batteries. This study presents a comparison of the requirements of parallel strings of batteries in three different popular topologies for open end winding induction motor (IM) drives in EV. The topologies analyzed are a 3-phase voltage source inverter (VSI), a Dual fed inverter and three single-phase HBridge VSIs. These converters are modulated using Space vector pulse width modulation (SVPWM) as it has better performance compared to Sine PWM. MATLAB-Simulink models are developed for the converter topologies. The simulation results show that the three single-phase inverter topology feeding the drive is the best alternative when compared on the basis of battery requirement and switch loss. Moreover, each H-bridge inverter (in the three single-phase inverter topology) can be used as charger and the problem of circulating current during charging will also be least as compared to other schemes. © 2022 River Publishers.
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. Â© 2024 IEEE.
Development of wide area monitoring system for smart grid application
(IOS Press BV, 2022) Malik, H.; Ahmad, M.W.; Alotaibi, M.A.; Almutairi, A.
PMU can directly measure positive sequence voltage, phase and system frequency. In this paper, the design and implementation for optimum placement of PMU in power system network (PSN) has been performed using 5 different intelligent approaches at an emulation platform. Different case studies based on IEEE 7, 14 and 30 bus system have been performed and analyzed. In the studies, PMU device is used for the measurement of voltage and current magnitude as well as its phase and its performance has been compared with measured real signals of PSN. PMU measurement gives the accurate results and reliability to PSN. But PMUs are not economical, so PSN operator needs to install a minimum number of PMU in PSN so that system should be fully observable in a real-Time scenario. In this paper for optimal placement of PMU, five different intelligent methods have been analyzed for three different bus systems and obtained results are compared. For the further validation of selected PMUs for the PSN, a state estimation using WLS algorithm has been performed using conventional data and PMU data on IEEE14 and IEEE30 bus systems. The obtained results for voltage estimation error and phase estimation error with and without PMU data are compared. © 2022-IOS Press. All rights reserved.
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. Â© 2023 IEEE.
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.
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.
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. Â© 2023 IEEE.
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. Â© 2021 IEEE.
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. Â© 2022 IEEE.
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]