Diagnosis of Inter-Turn Short Circuit for a Polyphase Induction Motor in Closed-Loop Vector-Controlled Drives

The main objective of this paper is to develop and experimentally verify a new technique to detect an inter-turn short circuit in one phase of a stator winding of an induction motor energized from a vector-controlled drive. This is in order to overcome the fault masking difficulties associated with the concept of depending on the actual magnetic field pendulous oscillation between the conventional voltage and current space vectors with respect to a reference that is unaltered by the compensation action of the drive. This technique is based on the flux pendulous oscillation phenomenon. This flux pendulous oscillation is also described in this paper, this in addition to the magnetic field pendulous oscillation previously addressed in prior publications. The new approach has been verified through experimental results which are represented here

Big Data and Urban Planning in Pakistan: A Case Study of The Urban Unit

This Major Paper presents research on the use of big data for urban planning and smart cities in the global South. It does so through a case study of the use of data at the Urban Unit in the province of Punjab, Pakistan. Based on a series of interviews and extended literature review, I trace the evolution of a science of cities and the growth of urban informatics and smart cities. I then define big data and discuss its related opportunities and limitations. The bulk of this Paper consists of a case study of the Urban Unit and research findings regarding the use of data in planning in Pakistan. A number of challenges to the use of data are identified, classified into challenges regarding data access and reliability, data literacy, and institutional challenges. A major finding is that the practice of urban planning in Pakistan is quite limited in a number of ways. The final chapter shares recommendations from interviewees and reflections on research findings, focusing on the politics of data. The paper ends by discussing future research directions

Improving the torque quality of a modulated pole machine

PhD ThesisThe research work carried out in this thesis is collaboration between Newcastle University and Höganäs AB, Sweden. A topology, termed ‘Separate Phase MPM’ was initially developed by Newcastle University and Höganäs where the machine takes advantage of mutual flux paths in order to increase the torque density of the machine, however had high cogging torque and back EMF harmonic content. The work presented in this thesis was carried out with an overall aim to minimise the cogging torque and back EMF harmonics in the Modulated Pole Machine (MPM) topology aimed toward electric bicycles. Various techniques are proposed and verified in this thesis to reduce the magnitude of unwanted voltage and torque harmonics, providing a smoother riding experience. Finite Element Analysis was carried out using Infolytica MagNet® on various design techniques which ultimately stemmed in 24 motor prototypes being constructed and tested during this PhD. The measured results are compared with each other to approve the technique that provides the optimum motor performance. It is shown that the peak cogging torque is reduced by 90% while the back EMF harmonics are diminished too, with a minor 2% reduction in mean back EMF. The efficiency and peak torque of the optimum motor is 8% and 10% higher, respectively, when compared with the base motor used in this study

Fault-Tolerant Operation of Delta-Connected Scalar- and Vector-Controlled AC Motor Drives

Operation and analysis of delta-connected ac motor-drive systems under fault-tolerant open-phase mode of operation is introduced in this paper for both scalar- and vector-controlled motor-drive systems. This technique enables the operation of the three-phase motor upon a failure in one of its phases without the need of a special fault-detection algorithm. It is mainly used to significantly mitigate torque pulsations, which are caused by an open-delta configuration in the stator windings. The performance of the fault-tolerant system was verified using a detailed time stepping finite element simulation as well experimental tests for a 5-hp 460-V induction motor-drive system and the results are presented in this paper This paper also compares the operation of this fault-tolerant mode of operation for the cases of scalar-controlled and closed-loop vector-controlled motor-drive systems

Fault-Tolerant Technique for Δ-Connected AC-Motor Drives

A fault-tolerant technique for motor-drive systems is introduced in this paper. The technique is merely presented for ac motors with Δ-connected circuits in their stator windings. In this technique, the faulty phase is isolated by solid-state switches after the occurrence of a failure in one of the stator phases. Then, the fault-tolerant technique manages current-flow in the remaining healthy phases. This technique is to significantly mitigate torque pulsations, which are caused by an open-Δ configuration in the stator windings. The performance of the fault-tolerant technique was experimentally verified using a 5-hp 460-V induction motor-drive system and the results are presented in this paper

Green Communications: Techniques and Challenges

Green technology has drawn a huge amount of attention with the development of the modern world. Similarly with the development in communication technology the industries and researchers are focusing to make this communication as green as possible. In cellular technology the evolution of 5G is the next step to fulfil the user demands and it will be available to the users in 2020. This will increase the energy consumption by which will result in excess emission of co2. In this paper different techniques for the green communication technology and some challenges are discussed. These techniques include device-to-device communication (D2D), massive Multiple-Input Multiple-Output (MIMO) systems, heterogeneous networks (HetNets) and Green Internet of Things (IoT)

E-Waste: An Emerging Problem of Innovative Society

In the past few years there is a revolution in electronic industry, which increases the volume and varieties of both solid and hazardous wastes. Urbanization Industrialization, fast changes in technologies leave a negative impact on health of human beings. Also increases the pollution in air, land and water. A growing municipal waste contains hazardous electrical and electronics products. When dumped in landfill will pollute the environment badly. This waste is usually named as E-waste (Electrical an Electronics Waste).In the absence of suitable techniques and protective measures, recycling e-waste can result in toxic emissions to the air, water and soil and pose a serious health and environmental hazard-waste is assuming serious proportions in developing countries and urgent steps need to be taken to mitigate this problem. This paper highlights the problem posed by e-waste and its hazards on environment and health

The Analytical Solution and Numerical Simulation for Ytterbium-Doped Silica Glass Fiber Laser Output Power

In this paper as the first the rate equations in end pump fiber laser have been solved analytically with negligible the scattering loss and the output power versus input power has been derived. The result were applied for a single and double clad Yb3+- doped silica glass fiber laser, for lasing transition it acts  as a quasi-four-level system the effect of the, type concentration core radius fiber length output  reflectivity, pump power and figure of inner cladding on the output lasing power have been studied. Keywords: Rare-Earth; Fiber Laser; Rate Equation; Quasi four levels

Interference Management in Dense 802.11 Networks

Wireless networks are growing at a phenomenal rate. This growth is causing an overcrowding of the unlicensed RF spectrum, leading to increased interference between co-located devices. Existing decentralized medium access control (MAC) protocols (e.g. IEEE 802.11a/b/g standards) are poorly designed to handle interference in such dense wireless environments. This is resulting in networks with poor and unpredictable performance, especially for delay-sensitive applications such as voice and video. This dissertation presents a practical conflict-graph (CG) based approach to designing self-organizing enterprise wireless networks (or WLANs) where interference is centrally managed by the network infrastructure. The key idea is to use potential interference information (available in the CG) as an input to algorithms that optimize the parameters of the WLAN.We demonstrate this idea in three ways. First, we design a self-organizing enterprise WLAN and show how the system enhances performance over non-CG based schemes, in a high fidelity network simulator. Second, we build a practical system for conflict graph measurement that can precisely measure interference (for a given network configuration) in dense wireless environments. Finally, we demonstrate the practical benefits of the conflict graph system by using it in an optimization framework that manages associations and traffic for mobile VoIP clients in the enterprise. There are a number of contributions of this dissertation. First, we show the practical application of conflict graphs for infrastructure-based interference management in dense wireless networks. A prototype design exhibits throughput gains of up to 50% over traditional approaches. Second, we develop novel schemes for designing a conflict graph measurement system for enterprise WLANs that can detect interference at microsecond-level timescales and with little network overhead. This allows us to compute the conflict graph up to 400 times faster as compared to the current best practice proposed in the literature. The system does not require any modifications to clients or any specialized hardware for its operation. Although the system is designed for enterprise WLANs, the proposed techniques and corresponding results are applicable to other wireless systems as well (e.g. wireless mesh networks). Third, our work opens up the space for designing novel fine-grained interference-aware protocols/algorithms that exploit the ability to compute the conflict graph at small timescales. We demonstrate an instance of such a system with the design and implementation of an architecture that dynamically manages client associations and traffic in an enterprise WLAN. We show how mobile clients sustain uninterrupted and consistent VoIP call quality in the presence of background interference for the duration of their VoIP sessions

Retail industry adopting change : adaptation: automation: benefits

This thesis contains the research on the key change adoptive agents/forces and the solu-tions to the world‟s rapidly growing and one of the most consumer facing industry. The trillions worth retail industries are undergoing the period of important restructuring inter-nally and externally. The author highlights the key factors that force the retail industry to adopt modern technologies for their daily business processes in order to be more competi-tive. The factors have been viewed in two perspectives 1-Internal (store/warehouse man-agement, human capital) and 2-Externally (customers, suppliers). In response of these factors, the research presents state of the art 1-Self Checkout System 2-RFID 3-Cloud Computing as tested and proven technologies that has been observed and implemented in the “Future Stores” by big box retailers. Finally the author discusses the tangible and in-tangible benefits to the retail business derived from the implementation of mentioned technologies. To meet the research demands, the writer constructs a theoretical frame-work by using the descriptive and exploratory research method as a secondary resource; while empirical research was conducted through semi structured phone interviews with experts from the retail industry and the retail management consultants. The results derived from theoretical study and empirical research show that the use of updated retail management technologies like Self-checkout System, RFID and Cloud Computing can reduce cost and management pain fairly. While the bigger impact of such adoptions is to build a seamless supply chain, customer experience management and business intelligence system; which plays a vital role to prolong the competitiveness and life cycle of retail business against future economic setbacks