Kafeel Ahmed Kalwar

Bio: Kafeel Ahmed Kalwar is an academic researcher from University of Malaya. The author has contributed to research in topics: Inverter & Uninterruptible power supply. The author has an hindex of 5, co-authored 7 publications receiving 242 citations. Previous affiliations of Kafeel Ahmed Kalwar include DHA Suffa University.

Inductively coupled power transfer (ICPT) for electric vehicle charging – A review

Abstract: The deficiency in the availability of petroleum products has given rise to the incorporation of electric vehicles (EVs) globally as a substitute for the conventional transportation system. Significant research has been pursued over last two decades in the development of efficient EV charging methods. A preliminary review of few methods developed for wireless charging revealed that ICPT is a promising and convenient method for the wireless charging of EVs. This paper includes the equivalent circuit analysis and characteristics of the ICPT system and focuses on the research progress in respect of the designs for the charging coil, leakage inductance compensation topologies, power level enhancement and misalignment toleration. The improvement in these factors has been essential for the implementation of EV charging. A brief discussion over design process and control of ICPT system has been added. Conclusions have been made on the basis of the information extracted from the literature and some future recommendations are provided.

Review: Uninterruptible Power Supply (UPS) system

Abstract: Uninterruptible Power Supplies (UPS) have reached a mature level by providing clean and uninterruptible power to the sensitive loads in all grid conditions. Generally UPS system provides regulated sinusoidal output voltage, with low total harmonics distortion (THD), and high input power factor irrespective of the changes in the grid voltage. This paper provides comprehensive review of UPS topologies, circuit configurations, and different control techniques used in the UPS system. A comparison based on the performance, size, cost, and efficiency of the system is presented. Different hybrid energy source UPS system and new generation UPS system for smart grid and micro-grid has been explained. Finally the paper describes performance evaluation of UPS system and explains different aspects that are to be considered for choosing a suitable UPS system by the user.

Coil Design for High Misalignment Tolerant Inductive Power Transfer System for EV Charging

Abstract: The inductive power transfer (IPT) system for electric vehicle (EV) charging has acquired more research interest in its different facets. However, the misalignment tolerance between the charging coil (installed in the ground) and pick-up coil (mounted on the car chassis), has been a challenge and fundamental interest in the future market of EVs. This paper proposes a new coil design QDQ (Quad D Quadrature) that maintains the high coupling coefficient and efficient power transfer during reasonable misalignment. The QDQ design makes the use of four adjacent circular coils and one square coil, for both charging and pick-up side, to capture the maximum flux at any position. The coil design has been modeled in JMAG software for calculation of inductive parameters using the finite element method (FEM), and its hardware has been tested experimentally at various misaligned positions. The QDQ coils are shown to be capable of achieving good coupling coefficient and high efficiency of the system until the misalignment displacement reaches 50% of the employed coil size.

Proportional-Resonant and Slide Mode Control for Single-Phase UPS Inverter

Abstract: Slide mode control (SMC) is recognized as the most robust control with high stability, while the proportional-resonant (PR) control shapes the output waveform closely according to the reference sinusoidal signal. Keeping in view the characteristics of slide mode and PR control, a cascaded controller is proposed for bipolar single-phase uninterruptible power supply (UPS) inverter. The outer voltage loop uses the PR control while the inner loop uses the SMC. Chattering in the SMC has been removed using smoothed control law in narrow boundary layer condition. The stability of the controller has been analyzed using Lypunov stability criteria. The smoothed control law applied to the pulse width modulator results in fixed switching frequency of the inverter. The performance of the controller has been analyzed for single-phase inverter through simulations and experiments for both the linear and non-linear loads. The performance of controller has been compared with the other techniques of SMC and standard...

Lithium-Ion Battery Storage for the Grid—A Review of Stationary Battery Storage System Design Tailored for Applications in Modern Power Grids

Abstract: Battery energy storage systems have gained increasing interest for serving grid support in various application tasks. In particular, systems based on lithium-ion batteries have evolved rapidly with a wide range of cell technologies and system architectures available on the market. On the application side, different tasks for storage deployment demand distinct properties of the storage system. This review aims to serve as a guideline for best choice of battery technology, system design and operation for lithium-ion based storage systems to match a specific system application. Starting with an overview to lithium-ion battery technologies and their characteristics with respect to performance and aging, the storage system design is analyzed in detail based on an evaluation of real-world projects. Typical storage system applications are grouped and classified with respect to the challenges posed to the battery system. Publicly available modeling tools for technical and economic analysis are presented. A brief analysis of optimization approaches aims to point out challenges and potential solution techniques for system sizing, positioning and dispatch operation. For all areas reviewed herein, expected improvements and possible future developments are highlighted. In order to extract the full potential of stationary battery storage systems and to enable increased profitability of systems, future research should aim to a holistic system level approach combining not only performance tuning on a battery cell level and careful analysis of the application requirements, but also consider a proper selection of storage sub-components as well as an optimized system operation strategy.

A review of Battery Electric Vehicle technology and readiness levels

Abstract: As concerns of oil depletion and security of supply remain as severe as ever, and faced with the consequences of climate change due to greenhouse gas emissions, Europe is increasingly looking at alternatives to traditional road transport technologies. Battery Electric Vehicles (BEVs) are seen as a promising technology, which could lead to the decarbonisation of the Light Duty Vehicle fleet and to independence from oil. However it still has to overcome some significant barriers to gain social acceptance and obtain appreciable market penetration. This review evaluates the technological readiness of the different elements of BEV technology and highlights those technological areas where important progress is expected. Techno-economic issues linked with the development of BEVs are investigated. Current BEVs in the market need to be more competitive than other low carbon vehicles, a requirement which stimulates the necessity for new business models. Finally, the all-important role of politics in this development is, also, discussed. As the benefit of BEVs can help countries meet their environmental targets, governments have included them in their roadmaps and have developed incentives to help them penetrate the market.

Design of loosely coupled inductive power transfer systems

Abstract: The model of inductive power system is set up,and how to choose the compensation topology and resonant frequency is analyzed.According to the analysis result,the model of inductive power system is set up,and the impact of the power transfer due to the variety of load is analyzed.

Opportunities and challenges for near-field wireless power transfer: A review

Abstract: Traditional power supply cords have become less important because they prevent large-scale utilization and mobility. In addition, the use of batteries as a substitute for power cords is not an optimal solution because batteries have a short lifetime, thereby increasing the cost, weight, and ecological footprint of the hardware implementation. Their recharging or replacement is impractical and incurs operational costs. Recent progress has allowed electromagnetic wave energy to be transferred from power sources (i.e., transmitters) to destinations (i.e., receivers) wirelessly, the so-called wireless power transfer (WPT) technique. New developments in WPT technique motivate new avenues of research in different applications. Recently, WPT has been used in mobile phones, electric vehicles, medical implants, wireless sensor network, unmanned aerial vehicles, and so on. This review highlights up-to-date studies that are specific to near-field WPT, which include the classification, comparison, and potential applications of these techniques in the real world. In addition, limitations and challenges of these techniques are highlighted at the end of the article.