Electrical and Electronics

Reduction in the number of component is a live problem in the domain of power electronics, as it is directly leads to reliability implication. Further reduction in active switches in the inverter topology is also beneficial for the cost factor point of view. In view of this, the present paper reports a novel inverter topology based on only four active switches as against the six switches topology widely reported in the literature. The said design is verified using PSIM software. The result shows good resemblance between our proposed four switches topology and conventional six switches topology.

A single feed circularly polarized c-shaped and circular patch antenna with improved axial ratio bandwidth is presented. In this article, both c-shaped slots and circular patch antenna were designed and by using the concept of switches like PIN diodes the circular polarization have been obtained. In this article the circular polarization was achieved by creating some asymmetry in the structure of an antenna. The performance characteristics of an antenna were explained in terms of its return loss characteristics and elevation radiation pattern of gain by using IE3D simulator.

A wireless sensor network (WSN) consists of spatially distributed autonomous sensors to monitor physicalor environmental conditions, such as temperature, sound, pressure, PIR etc. and to cooperatively pass their data through the network to a main location. The development of wireless sensor networks was motivated by military applications such as battlefield surveillance; today such networks are used in many industrial and consumer applications, such as industrial process monitoring and control, machine health monitoring, and so on. The WSN is built of "nodes" from a few to several hundreds or even thousands, where each node is connected to one (or sometimes several) sensors. Each such sensor network node has typically several parts: a radio transceiver with an internal antenna or connection to an external antenna, a microcontroller, an electronic circuit for interfacing with the sensors and an energy source, usually a battery or an embedded form of energy harvesting. A sensor node might vary in size from that of a shoebox down to the size of a grain of dust, although functioning "motes" of genuine microscopic dimensions have yet to be created. The cost of sensor nodes is similarly variable, ranging from a few to hundreds of dollars, depending on the complexity of the individual sensor nodes. Size and cost constraints on sensor nodes result in corresponding constraints on resources such as energy, memory, computational speed and communications bandwidth. The topology of the WSNs can vary from a simple star network to an advanced multi-hop wireless mesh network. The propagation technique between the hops of the network can be routing or flooding.

The analog speech signal can be used for interacting with machines, computers or robots. In this case, speech algorithm is capable to recognize the voice commands that are given as inputs to a mobile robot through wireless XBee modules. It is actually a form of Word Recognition. In this presented paper, a voice command recognition system is going to be developed by using Artificial Neural Network (ANN). The Commands that used here are all in Nepali Languages (used in North East India). Linear predictive coding (LPC) has been applied to represent speech signal in frames in early stage. Features from the selected frames are used to train multilayer perceptrons (MLP) using back-propagation. The same routine is applied to the speech signal during the recognition stage and unknown test patterns are classified to the nearest patterns. In short, the selected frames represent the local features of the speech signal and all of them contribute to the global similarity for the whole speech signal. The analysis, design and development of the automation system are done in MATLAB, in which an isolated word speaker independent digits recogniser is developed.

Over 70% of the photovoltaic (PV) systems are designed with transformers which are galvanic isolations. However, such inverters are big, heavy and expensive with low efficiency. In this work, a transformer-less PV system is introduced. It is smaller, lighter, and cheaper with higher efficiency as compared to the transformer of the same rating. The proposed inverter employs push pull circuit, an H bridge circuit, the oscillating circuit, an automatic changeover dual battery bank and an RF remote control circuit unit. The switching technique of the proposed inverter consists of a pulse width modulation system along with grid synchronization condition. As the suggested method is entirely transformer-less, there is a reduction in transformer loss which tremendously reduces the total harmonic distortion (THD) to even less than1% with an assumption of; inductor is ideal without any internal resistance, the switches and diodes are ideal with the dead line between the switches are neglected. A filtering capacitor provides a nearly constant output current which stabilizes the system rapidly and reduces harmonics generated by the switching circuit. Overall performance of the proposed inverter was simulated with PROTEUS and validated with MATLAB which produced a pure sinusoidal waveform as the output voltage. The proposed inverter minimizes size and increases the inverter efficiency to 90% which can be used in our homes, offices and schools for lightening and charging.

Si-based resonant interband tunneling diodes (RITD) with spacer thicknesses varying from 2.5 to 25 nm was grown and fabricated at Baghdad University. The effect of spacer thickness on the peak-to-valley current ratio (PVCR), peak current density (JP), and voltage swing (VS) was studied for determining the static or dynamic read access memory (SRAM, DRAM). By increasing the tunneling spacer thickness up to 12 nm, RITDs with VS are reduced below 0.3V; this is suitable for low-power tunnel diode SRAM applications. The JP increased as the spacer thickness increased from 2.5nm to 5nm. As the spacer thickness increased above 5nm, the Jp decreased. Using a low-current-density in this paper, a bread-boarded one-transistor tunneling-based SRAM (TSRAM) memory cell with low standby power consumption was demonstrated, where the standby power of this 1T TSRAM is estimated to be 65nW/cell using the 10-?m diameter RITDs. The result demonstrates the potential of Si-based tunnel diodes for low-power memory applications.

One of the key issues in assessing the reliability of power systems. Studies and projects to improve the reliability of the distribution network has mostly been focused on changing the structure of the distribution system or transmission the Executive them even more expensive and is not available. In this work, the development of DG units in distribution networks the presence of these materials ensure that the indicators qabylt distribution network will pay. In this thesis, the main goal of distributed production system effects on the reliability of the system with regard to limitations related parameters such as voltage profiles and losses in the distribution network. Concepts and indicators of the reliability of the network and the ongoing impact of DG units on the reliability of the distribution network will be investigated. Finally, the intelligent ant colony algorithm to determine the optimal location generation units in order to achieve the best reliability indices by including restrictions have been charged. The proposed algorithm is tested on 34 bus IEEE network simulation, simulated and results are compared.

In this paper, a testable design with good fault identification capability is used for analysis and diagnosis of stuck-at and bridging faults in Exclusive-OR Sum of Product Reed-Muller canonical circuits, independent of the function for a given number of inputs. Factors of identifiability and distinguishability have been defined and determined. Further, a compact method of representing the circuit outputs has been adopted for ease of tabulation and comparison. Simulations of Single stuck-at, Double stuck-at, OR-bridging and AND-bridging faults for a few random functions have been carried out through MATLAB coding. From the test results, it was found that the fault detection for the set of random functions was more than 95% for most of the functions except few cases, with just n+5 test vectors compared to 2n test vectors required for conventional testing. The location of the fault can also be diagnosed through the output sets.

The conventional electric grid is continuously shifted towards technological transformation of Smart Grid. The gradually increasing electricity cost, inadequate infrastructure, electricity losses at various stages, carbon footprint and climate changes are some of the major player for paradigm shift towards smart grid. The smart grid is next generation grid network that promises advantage such as decentralized control, digitalization, flexibility, intelligence, resilience, sustainability, and customization. In this article, we are put forth some of pioneer development and challenges faced in the smart grid environment. This article also discusses the smart grid development regarding with Indian perspectives.

Cognitive Radio (CR) is an imaginative innovation that goes for huge upgrades in productivity of range utilization. CR will change the way the radio range is managed, additionally requires new empowering technique s, for example, enhanced range detecting and element range task. Cognitive radio (CR) systems are shrewd systems that can naturally sense the earth and adjust the correspondence parameters in like manner. These sort of systems have applications in element range get to, conjunction of different remote systems, obstruction administration. They are touted to drive the up and coming era of gadgets and applications. Noticeably, the subjective radio system worldview postures numerous new specialized difficulties in convention outlines, control effectiveness, range administration, range recognition, environment awareness, new circulated calculation point, conveyed range estimations, Quality of administrations certifications, and security. Conquering these issues turns out to be considerably all the more difficult because of non-uniform range and other radio asset designation plans, monetary contemplations, the inborn transmission debilitations of remote connections, and client portability. Psychological radio is a rising innovation that empowers the adaptable improvement and arrangement of profoundly versatile radios that are based upon programming characterized radio innovation. Psychological radio has been considered as a key innovation for future remote interchanges and portable figuring. We see that the subjective radios can shape Cognitive radio systems (CRN) by extending the radio connection elements to network layer capacities or more.