Electrical Engineering

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The estimation of Maximum Power Point (MPP) of photovoltaic (PV) array is essential for integration of solar power to microgrid. This paper presents the estimation of Maximum Power Point of a solar photovoltaic array under different environmental conditions (i.e. different temperature and solar irradiation) using Levenberg Marquardt method. The estimation is done using the single diode based model parameters of photovoltaic (PV) module. The photovoltaic (PV) module parameters are estimated from the data sheet values given by manufacturer. The estimated Maximum Power Point (MPP) values of the PV array under different environmental condition are presented in the simulated current-voltage and power-voltage characteristics. It is demonstrated that the estimated MPP values of the PV array are nearly equal to simulated MPP values. © 2014 IEEE.

(SoE) School of Engineering

World University root node

2014 IEEE Innovative Smart Grid Technologies - Asia, ISGT ASIA 2014

Estimation of Maximum Power Point of PV array using datasheet values for microgrid integration

We consider a two-user binary multiple access setup suitable for pulse based communications. The link from each user to the receiver is modeled by independent time-varying Z-channel. We consider the cross-over probabilities of the Z-channels as the state of the process. Each user has access only to its own state process and is unaware of the other user's states. The receiver observes the superposition of the symbols from the links. Assuming a block fading state process, we propose adaptive communication schemes, which also ensure outage-free communication in any transmission block. Furthermore, the proposed strategies turn out to be throughput optimal for highly dispersive systems. {\textcopyright} 2014 IEEE.

2014 20th National Conference on Communications, NCC 2014

MAC channel with states for pulse-based communication systems

Thermal diffusivity of anodic alumina (AAO) templated bismuth telluride nanowires has been measured using recently proposed frequency modulated thermal wave imaging (FMTWI). The technique provides a fast and efficient non-contact approach for in-plane thermal characterization of nanomaterials. An intensity modulated up-chirp signal is applied as photothermal excitation and the thermal response is monitored using an infrared (IR) thermography based temperature sensing system. Thermal diffusivity of the sample is experimentally assessed using the multiple phase information extracted from a single run of the experiment. This feature considerably reduces the operational time of the experiment as compared to similar lock-in thermography based approaches. This unique approach of solely using the phase information for thermal diffusivity measurements, allows the experiment to be more immune to the local variations in surface temperature and emissivity of the radiating surface. The experimental details of the technique are discussed, with practical measurement of thermal diffusivity of Bi2Te3/AAO nanocomposite in direction perpendicular to the nanochannel axis. © 2014 SPIE.

Proceedings of SPIE - The International Society for Optical Engineering

Thermal diffusivity estimation of templated nanocomposite using frequency modulated infrared imaging

Reinforcement learning (RL) algorithms that employ neural networks as function approximators have proven to be powerful tools for solving optimal control problems. However, neural network function approximators suffer from a number of problems like learning becomes difficult when the training data are given sequentially, difficult to determine structural parameters, and usually result in local minima or overfitting. In this paper, a novel on-line sequential learning evolving neural network model design for RL is proposed. We explore the use of minimal resource allocation neural network (mRAN), and develop a mRAN function approximation approach to RL systems. Potential of this approach is demonstrated through a case study. The mean square error accuracy, computational cost, and robustness properties of this scheme are compared with static structure neural networks. © Springer International Publishing Switzerland 2014.

Smart Innovation, Systems and Technologies

Neural networks with online sequential learning ability for a reinforcement learning algorithm

Spiraling of conductors in a helical winding of a transformer may lead to a catastrophic failure under the action of torsional short-circuit electromagnetic forces. Torsional forces are produced by the interaction of the axial component of the short-circuit current and the radial component of the leakage magnetic flux density. In this paper, 3-D magnetostatic analysis has been performed to determine the leakage magnetic-field distribution in a 130-MVA power transformer. Torsional electromagnetic forces are calculated from the analysis to determine circumferential displacements of conductors of its low-voltage helical winding. Furthermore, mechanical stress components are computed and a factor of safety is defined, which gives an indication as to whether the winding conductors are in the elastic or plastic zone. The numerical results thus obtained by the finite-element method are verified using the first principles from mechanics. The effect of looseness in the inner support structure on the von-Mises equivalent stress and, hence, on the factor of safety has been studied. © 1986-2012 IEEE.

IEEE Transactions on Power Delivery

Coupled electromagnetic-structural analysis of the spiraling phenomenon in a helical winding of a power transformer

This paper presents the design of Memristor-capacitor based startup circuit. Memristor is a novel device and has many advantages over conventional CMOS devices such as no leakage current and is easy to manufacture. In this work the switching characteristics of memristor is utilized. First the theoretical equations describing the switching behavior of memristor are derived. To prove the switching capabilities of Memristor, a startup circuit based on series combination of Memristor-capacitor is proposed. This circuit is compared with the reference circuit (which utilizes resistor in place of memristor) and the previously reported MOSFET based startup circuits. Comparison of different circuits was done to validate the results. Simulation results shows that memristor based circuit attains on (I = 2.25 mA) to off state (I = 10 μA) in 2.8 ns while the MOSFET based startup circuits takes (I = 1 mA) to off state (I = 10 μA) in 55.56 ns. However no significant difference in switching time was observed when compared with resistance based startup circuit. The benefit comes in terms of area because much larger die area is required for manufacturing of resistance in comparison to fabrication of memristor. © 2014 IEEE.

Proceedings of the 2014 International Conference on Advances in Computing, Communications and Informatics, ICACCI 2014

Memristor-capacitor based startup circuit for voltage reference generators

Two novel triads based on a diketopyrrolopyrrole (DPP) central core and two 4,4-difluoro-4-bora-3a,4a-diaza- s - indacene (BODIPY) units attached by thiophene rings have been synthesised having high molar extinction coefficients. These triads were characterised and used as donor materials in small molecule, solution processable organic solar cells. Both triads were blended with PC 71 BM as an acceptor in different ratios by wt % and their photovoltaic properties were studied. For both the triads a modest photovoltaic performance was observed, having an efficiency of 0.65%. Moreover, in order to understand the ground and excited state properties and vertical absorption profile of DPP and BODIPY units within the triads, theoretical DFT and TDDFT calculations were performed. © 2014 Cortizo-Lacalle et al; licensee Beilstein-Institut. License and terms: see end of document.

Fulltext

Beilstein Journal of Organic Chemistry

Solution processable diketopyrrolopyrrole (DPP) cored small molecules with BODIPY end groups as novel donors for organic solar cells

This paper presents the design of a dual-port dual-band circular polarized annular slot antenna, suitable to use in the feed-back path of an oscillator resulting in an active antenna configuration. The proposed antenna is designed to radiate and transmit equal amounts of power. The return loss of the proposed antenna is higher than that desired for one-port antenna application at the desired dual-band frequencies. The antenna is fabricated on one side of a Neltec substrate (εr=3.2 and thickness = 0.762 mm) and the microstrip feeding line is fabricated on the opposite side of the board. The antenna was designed to operate at WLAN bands centered at 2.4 and 5.2 GHz. The simulated and measured results show fairly good agreement. The measured return losses were found 10 dB at 2.4 GHz and 14.5 dB at 5.2 GHz while simulated return losses were 8.57 dB at 2.4 GHz and 15.2 dB at 5.2 GHz. The radiation pattern is approximately omnidirectional at both frequencies in H-plane. © 2014 IEEE.

2014 IEEE International Wireless Symposium, IWS 2014

Circular polarized dual port annular slot antenna

This paper proposes a novel and computationally efficient method of compressive domain sub-band filtering. The technique utilizes the conjugate symmetry property of DFT matrix to achieve sub-band filtering of a wide-band multi-band input signal sensed by the Modulated Wide-band Converter (MWC) architecture. The proposed technique has flexibility of filtering single or multiple sub-bands of a wide-band input signal, which is sparse in frequency domain, without increase in additional computational cost. The filter bandwidth can also be controlled by increasing the number of channels in sensing architecture. The simulation result shown in this paper includes sub-band filtering of a frequency domain sparse multi-band input signal with or without noise. BER performance of a BPSK modulated signal after filtering and demodulation using the proposed technique is also presented to analyze the impact of sub-band filtering. © 2014 IEEE.

Sub-band filtering in compressive domain

This paper proposes a Compressive Signal Processing Receiver based on Modulated Wideband Converter (MWC) sensing architecture and power spectrum estimation method in compressive domain for interference detection and filtering. The proposed receiver uses the signal processing method capable of reconstructing the unknown power spectrum of a signal from the MWC output samples in compressive domain. Interference detection achieved with respect to ITU or service provider defined PFD limits for operating frequency band on per Hz basis for a given receive system. Interference filtering by a novel method of compressive domain filtering which exploits the conjugate symmetry of DFT matrix for modifying the sensing matrix to achieve the sub-band filtering in compressive domain for interference removal is proposed. Proposed receiver is suitable for next generation of wideband satellite transponders. Matlab simulation to verify the proposed algorithm and results are presented. © 2014 IEEE.