Electrical and Electronics

This paper presents design and analysis of an LCL-based voltage source converter using for delivering power of a distributed generation source to power utility and local load. LCL filer in output of the converter analytically is designed and its different transfer functions are obtained for assessment on elimination of any probable parallel resonant in power system. The power converter uses a controller system to work on two modes of operation, stand-alone and grid-connected modes, and also has a seamless transfer between these two modes of operation. Furthermore, a fast semiconductor-based protection system is designed for the power converter. Performance of the designed grid interface converter is evaluated by using an 85-kVA industrial setup.

Cognitive radio (CR) can successfully deal with the growing demand and scarcity of the wireless spectrum. To exploit limited spectrum efficiently, CR technology allows unlicensed users to access licensed spectrum bands. Since licensed users have priorities to use the bands, the unlicensed users need to continuously monitor the licensed user’s activities to avoid interference and collisions. How to obtain reliable results of the licensed user’s activities is the main task for spectrum sensing. This work will mainly focus on the spectrum sensing based on energy detection algorithm.

The first real signal processing element just after the antenna that determine the noise performance and linearity of the overall system in RF receiver is Low Noise Amplifier (LNA) which makes it one of the most important and sensitive block of a RF receiver that can improve the performance of the circuit. The RF front end is the most significant part and any electronic warfare can damage the entire circuit performance. It is not possible to analyze theoretically under conditions such as change in input power, frequency, and design parameters. It is mandatory to propose the relationship between damage rate and the power absorbed in order to reduce the damage rate. This paper analyzes the power absorbed by the non-linear element present in the LNA circuit. The power absorption is verified by varying the input and output impedances. Hence, this paper identified the parameters that increase the damage rate of LNAs and suggested designs to reduce the damage rate.

The design and optimization of broadband, beam steering and high gain traveling wave slotted waveguide array antenna using substrate integrated waveguide (SIW) is discussed in this paper. The antenna has been designed on Rogers 5880 with a dielectric constant of 2.2 and height of 0.762 mm. The functional frequency range is from 13.5 - 15.5 GHz and the gain is about 14 dB at 15.5 GHz. The proposed antenna radiation beam steers from -330 at 13.5 GHz to 50 at 15.5 GHz in elevation plane. This antenna possesses the benefits of low profile, low weight, low cost and it can be used for Ku band applications.

The QRS complex is the most striking waveform within the electrocardiogram (ECG). QRS provides the fundamentals for almost all automated ECG analysis algorithms. We proposed a novel method for classification of ECG beats using shared counters. We first developed a real-time QRS detection technique using two-phase hashing to extract precise QRS points. Then we implement a novel ECG beat classifier to profile each patient’s normal cardiac behavior. Our technique relies more on the data stream corresponding to ECG beats than any particular feature. We use the concept of shared counters to minimize the memory requirement. The algorithm automatically adjusts parameters periodically to adapt to ECG changes as QRS morphology and heart rate. Having such profile is essential for various diagnosis (e.g., arrhythmia) purposes. One application of such profiling scheme is to automatically raise an early warning flag for the abnormal cardiac behavior of any individual.

ZnO is introduced as an alternative to TiO2 in dye sensitized solar cells (DSSCs) due to its band gap similar to TiO2, higher electron mobility, and flexible procedures of preparations. Several samples of ZnO films are prepared with the hydrothermal synthesis method and the sol-gel technique, respectively. These ZnO films were assembled as photo anodes in DSSCs using N3 dye as the sensitizer. The performance of dye sensitized solar cells is mainly based on the dye as a sensitizer. Natural dyes have become a viable alternative to expensive and rare organic sensitizers because of its low cost, easy attainability, abundance in supply of raw materials and no environment threat. The nature of these pigments together with other parameters has resulted in varying performance. This review briefly discusses the emergence, operation and components of dye explained solar cells together with the work done on natural dye based dye sensitized solar cells over the years.

Continuous stirred tank reactor system is a typical chemical reactor system with complex non linear dynamic characteristics. There has been considerable interest in its state estimation and real time control based on mathematical modeling. However, the lack of understanding of the dynamics of the process, the highly sensitive and non linear behavior of the reactor, has made difficult to develop the precise mathematical modeling of the system. An efficient control of the product concentration in CSTR can be achieved only through accurate model. In this paper, attempts are made to alleviate the modeling difficulties using “Artificial Intelligence” (AI) techniques such as neural, fuzzy and neuro-fuzzy. Simulation results demonstrate the effectiveness of Artificial Intelligence modeling techniques. The performance comparison of different modeling techniques has been given in terms of root mean square error.

Photovoltaic (PV) Smart Grid systems can make a positive contribution to the sustainability of rural communities in developing countries that do not have access to electricity grid. Integration of solar photovoltaic system with diesel generator for remote and rural areas would assist in expanding the electricity access in the tropical region. The Smart Grid approach performance in terms of technical and economic aspects and their prospects has been presented in this paper.

In this paper, a modified distributive arithmetic algorithm is designed and implemented on FPGA for OFDM system. In order to reduce the number of storage elements required to store the partial products, input register is split into two sections. Bottom section of register is used to access the partial products and the top section of input register is used as select line of multiplexer structure. The addition of partial products is executed in parallel to reduce the latency of the DWT/IDWT computation. The modified DA algorithm is modeled using HDL and is implemented on Spartan 3E devices. The design operates at 60 MHz and consumes power less than 0.036 W and is thus suitable for low power applications. The developed DWT/IDWT model can be integrated with QAM modulator and form a OFDM system used for power line applications.

Electricity power distribution networks are sometimes disturbed by a phenomenon known as ferroresonance. Causes, effects and remedies of ferroresonance are discussed in this paper. It is a nonlinear resonance in transformers which occurs during switching operations and lightning on networks containing inductors, capacitors and iron core materials that easily saturates. Overvoltages, overcurrents and distortions results’, causing overheating, damage to equipment, transformers and sometimes explodes. Difficult to predict, hence, in solving its problems, no mathematical solution is applicable yet. However, theoretical principles, simulations and measurements are commonly adopted. Secondary sources were used and the paper undoubtedly shall guide designers, manufacturers of transformers and operating personnel to ensure equipment longevity and safe operations for effective service delivery.