Fault Resilient and Reconfigurable Power Management Using Photovoltaic Integrated with CMOS Switches

A Photovoltaic (PV) cell is a device which converts light incident upon it to electric current. The push for green energy due to global warming and diminution of fossil fuels opens up a huge market for PV cells. Hence, a lot of interest is being garnered for using PV cells for various applications. However, a PV module\u27s performance degrades due to many anomalies such as failure of individual PV cell within a module, the opening of interconnection, a short circuit in the connection, failure of bypass diode, failure in voltage regulator or partial shading. To some extent all of these issues can be addressed by introducing a transistor as a switch in a PV module. This kind of architecture also enables the PV module to switch between high voltage with low current or high current with low voltage. Moreover, such architecture is handy when PV modules are deployed at remote locations where manual intervention in the case of fault or power management becomes too expensive or impossible. With advancements in semiconductor processing, the MOSFET switches can now be integrated with a PV cell for improved reliability. In this research project, we introduced addressable switches for PV cell that enable the creation of real-time reconfigurable power buses or power island. Moreover, for PV module deployed at a remote location, we have installed an architecture that let the PV module self-detect faulty PV cells or partial shading condition. Such algorithms detect faulty PV cells or PV cells under partial shading within the module such that the performance of the PV module does not become degraded. The algorithms actively use an embedded computing device to predict the output power based on a number of PV cells connected in series and parallel; then the computed power is compared with the measured power for faulty condition detection. Typically, for achieving such kind of computing architecture a single-diode based PV module modeling technique is used. However, all of these modeling techniques have an exponential term due to the presence of a diode, the computing of output power and performance of PV module becomes power intensive and it is difficult to implement on an embedded system. Also, due to the presence of the exponential term, there is no closed form solution for IPV versus VPV (output current of PV cell versus output voltage of a PV cell). We have introduced a PV module modeling using an N-channel MOSFET transistor that doesn\u27t have an exponential term. Moreover, a quadratic equation based solution is obtained that can be solved for calculating the load current. Using the same technique PV module can be also be modeled for various configuration. Additionally, with MOSFET based PV cells modeling enables the modeling CMOS-with-PV which is also presented in this work

Synthesis and Characterization of YBa2Cu3O7-x Superconductor

We have synthesized YBCO superconductor via solid state reaction route and characterized it with XRD, R vs. T and I-V measurements. From XRD graph we have identifying the phase formation of our sample and from R vs. T measurement we found the onset of superconductive transition occur at (TCO) 92.17 K; which also gives an extra supporting data towards the phase formation. We also subjected our sample for I-V characterization at different temperatures (30, 35, 45, 50 K) through four probe method and able to find out the critical current density at the subsequent temperatures and found a decrement of critical current density with increment of temperatur

Generic Pest Risk Analysis for Potato in Nepal

Pest Risk Analysis (PRA) is the process of evaluation for biological and economic evidences in order to determine whether a pest should be regulated under phyto-sanitary measures. The present mini review highlights the potential potato pathogen list recorded in Nepal harmful for potato production and productivity. At global scale altogether 135 potential quarantine pests (PQP) for potato has been recorded, while in Nepal only 92 PQP were recorded. Out of those 52, 13 and 27 were fungi, bacteria and viruses respectively. Among the 92 PQP, 34, 30 and 13 were considered at high, medium and lower risk type pathogens for potato. There was no information available on other 15 PQP.Journal of Nepal Agricultural Research Council Vol.3 2017: 32-3

Application of root cause analysis in improvement of product quality and productivity

Root-cause identification for quality and productivity related problems are key issues for manufacturing processes. It has been a very challenging engineering problem particularly in a multistage manufacturing, where maximum number of processes and activities are performed. However, it may also be implemented with ease in each and every individual set up and activities in any manufacturing process. In this paper, root-cause identification methodology has been adopted to eliminate the dimensional defects in cutting operation in CNC oxy flame cutting machine and a rejection has been reduced from 11.87% to 1.92% on an average. A detailed experimental study has illustrated the effectiveness of the proposed methodologyPeer Reviewe

Vacuum Electronic Devices and Applications

This issue of Defence Science Journal (DSJ) contains a collection of nine manuscripts from National Symposium on Vacuum Electronic Devices and Applications (VEDA-2019). Vacuum Electronic Devices and Applications Society organises VEDA symposium/conference/workshop every year at different locations of India. VEDA has established itself as a leading platform for active and innovative research of microwave tubes. It provides a forum for knowledge sharing and exhibition of theoretical and technological development in the general areas of vacuum electronics devices and its system applications. It organises special session to enhance Research Institutes – Industries and Academia Interaction