Department of Electrical Engineering

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IIT Jodhpur

This paper presents a wavelet fuzzy based protection scheme for a double line transmission system with unified power flow controller. The protection scheme makes use of current signals at both the ends of transmission line which are synchronized with the help of global position system clock. A wavelet based multiresolution analysis is used to find the detailed coefficients of these signals which are utilized to calculate fault index. These fault indexes are compared with a threshold value to detect and classify faults on transmission system. The approximate decomposition of the current signals is utilized to locate the fault using Fuzzy logic from their respective terminals. The proposed algorithm has been tested successfully for various faults at different locations. © 2015 Elsevier Ltd.All rights reserved.

World University root node

International Journal of Electrical Power and Energy Systems

A transient current based double line transmission system protection using fuzzy-wavelet approach in the presence of UPFC

This paper proposes a design methodology to stabilize collective circular motion of a group of N-identical agents moving at unit speed around individual circles of different radii and different centers. The collective circular motion studied in this paper is characterized by the clockwise rotation of all agents around a common circle of desired radius as well as center, which is fixed. Our interest is to achieve those collective circular motions in which the phases of the agents are arranged either in synchronized, in balanced or in splay formation. In synchronized formation, the agents and their centroid move in a common direction while in balanced formation, the movement of the agents ensures a fixed location of the centroid. The splay state is a special case of balanced formation, in which the phases are separated by multiples of 2π/N. We derive the feedback controls and prove the asymptotic stability of the desired collective circular motion by using Lyapunov theory and the LaSalle's Invariance principle. © 2015 American Automatic Control Council.

Proceedings of the American Control Conference

Stabilization of collective motion in synchronized, balanced and splay phase arrangements on a desired circle

Power line communications is the use of power lines for the dual purpose of power transmission and data transmission. It is an emerging field of communication for the home area network of smart grid. Power line noise, namely background noise and impulsive noise, significantly affects the performance of power line communication systems. In this paper, we derive the condition for optimum detection of quadrature phase shift keying signals over Nakagami-m distributed additive background noise in power line communication system. The probability density function and the cumulative distribution function of the decision variables for the real part and imaginary part of the background noise are derived. We use the copula approach to model the dependence among the decision variables. The analytical average symbol error rate and average bit error rate of the PLC system is numerically computed. Simulations suggest that the proposed receiver performs significantly better than the existing suboptimal receiver. © 2015 IEEE.

2015 IEEE International Symposium on Power Line Communications and Its Applications, ISPLC 2015

Maximum likelihood decoding of QPSK signal in power line communications over Nakagami-m additive noise

Power line communication (PLC) utilizes power lines for the purpose of electronic data transmission. The performance of a PLC system is significantly affected by the additive and multiplicative power line noises; the additive noises are of two types, namely background noise and impulsive noise. Whereas, the multiplicative PLC noise leads to fading in the received signal strength. In this paper, we evaluate the performance of a PLC system over log-normal fading channel under Nakagami-m distributed additive background noise assuming binary phase shift keying modulation scheme. The analysis involving log-normal fading is very complicated. Hence we use a novel gamma approximation to log-normal distribution for our analysis. We evaluate the probability density function of the decision variable. A closed-form expression of the analytical average bit error rate of the considered system is derived. We also compute the diversity order of the considered PLC system. The validity of the derived analytical expressions is closely verified by the simulation results. © 2015 IEEE.

IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC

Performance evaluation of PLC with log-normal channel gain over Nakagami-m additive background noise

Conventional bonding techniques like fusion, glass frit, soldering, eutectic, and anodic bonding, have been used in packaging for micro-electro-mechanical systems (MEMS). These bonding techniques require high temperature which results in bending/buckling of MEMS devices especially in case of hanging structures. In this work, low temperature and low cost bonding techniques with commercially available epoxy 320 NC and photoresist SU-8 2010 are done. Bonding with commercially available epoxy 320 NC at room temperature leads to spreading of epoxy in device region and affects the device performance. To define bonding ring dimensions, photoresist SU 8 2010 is used as an adhesive. Sharp dimensions of SU 8 2010 bonding ring are achieved using lithography. Top silicon cap is fabricated using TMAH etching. The bonds made with these techniques gave good shear strength, as measured with an indigenous setup. © 2015 IEEE.

RSM 2015 - 2015 IEEE Regional Symposium on Micro and Nano Electronics, Proceedings

Low temperature bonding techniques for MEMS devices

This paper presents a low cost fabrication process for development of electrostatically actuated optical microstructures. To illustrate the process - a design, fabrication and measurement iteration for digital micromirror test structures is presented. The structures are fabricated on Single Crystal Silicon wafer using surface micromachining and gold electroplating. The major focus of the work has been on the process compatibility with conventional CMOS fabrication technology, lower cost, complexity, lower surface roughness and susceptibility of compliant structures to thermal cycling during the process. Thelstructures consist of 1-2 micron thick micromirrors suspended at a height of 2-5 micron and surface roughness of 22-30 nm. Vertical deflection (3 micron), pull-in voltage (31V) and mechanical resonance frequency (25 KHz) match within 5-10% to the simulated design. The approach can be extended to realize optical switches, light modulators, grating structures, barcode readers and optical scanners. © 2014 IEEE.

11th IEEE India Conference: Emerging Trends and Innovation in Technology, INDICON 2014

Low cost process for development of electrostatically actuated optical devices using gold electroplating

This paper outlines the power handling capabilities of metal contact switches. The appropriate choice of configuration (inline or offline) reduces the probability of self actuation and allows high input RF power. The shape and position of the contact spots decides the current density and accordingly allows the permissible amount of power to flow without causing any failure. These two design aspects are taken into consideration and accordingly switch is designed with an insertion: −0.1086 dB, isolation: −32.5 dB and return loss: −18.07 dB. The pull in voltage of the beam is simulated to 19 V. Reinforcing of the beam is done to avoid curling of beam, self actuation at high power and to provide optimum contact force (105 µN) in order to reduce contact resistance. The power to be handled by the switch is 15.6 W, when no temperature considerations are taken into account. © 2014, Springer-Verlag Berlin Heidelberg.

Microsystem Technologies

Design aspect of high power handling applications: metal contact switches

The design, fabrication, and mechanical characterization of a compact-reduced stiction see-saw radio frequency MEMS switch are presented. The switch has a resonance frequency of 9.8 kHz with a corresponding switching speed of 46 μs. Use of a floating metal layer and optimal contact area ensures reduced stiction and smaller capacitive leakage. Overall size of the switch is 0.535 (0.50×1.070) mm2. Reduction in up-state capacitance also results in improvement in self-actuation voltage, insertion, and return loss. The optimized topology has improved the stiction and power handling of the switch. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE).

Journal of Micro/ Nanolithography, MEMS, and MOEMS

Design and fabrication of a reduced stiction radio frequency MEMS switch

In this paper, the steady-state behaviour of discretized terminal sliding mode control is studied. A discrete terminal sliding mode control is designed by discretizing the continuous-time system and then the steady-state behaviour is analysed in terms of periodic orbits. We have shown that by this discrete terminal sliding mode control the discretized second order system exhibits only period-2 motion in steady-state. To ensure this, existence and stability conditions of all possible periodic orbits are found out analytically and shown that only period-2 conditions are satisfied by the state evolution of the discretized system in steady-state. Next, a higher order single-input-single-output system is considered and we also establish that only period-2 motion exists in steady-state. © 2015 Elsevier Ltd.

Automatica

Steady-state behaviour of discretized terminal sliding mode

Tightly regulated power electronic converters show negative impedance characteristics and behave as a constant power load (CPL) which sink constant power from their input bus. This incremental negative impedance characteristics of tightly regulated point-of-load converters in multi-converter power systems have a destabilising effect on source converters and may destabilise the whole system. Similar phenomena also occur in many situations like dc microgrid, vehicular power system. Here, the authors present a robust pulse-width modulation-based sliding-mode controller for a dc/dc boost converter feeding the CPL in a typical dc microgrid scenario. A non-linear surface is proposed which ensures constant power to be delivered to the load. The existence of sliding mode and stability of the sliding surface are proved. The proposed controller is implemented using OPAL-RT real-time digital simulator on a laboratory prototype of dc/dc boost converter system. The effectiveness of the proposed sliding-mode controller is validated through simulation and experimental results under different operating conditions. © The Institution of Engineering and Technology 2015.