Majlesi Journal of Electrical Engineering
Volume:12 Issue: 1, Mar 2018

A higher-order sliding approach to control a bioreactor model is proposed by non-commensurate fractional equations. According to existing conditions and chattering reduction, a high-order sliding mode approach has been chosen to design the controller. A mathematical problem is a barrier to use the high-order sliding mode approach for fractional order systems. The contribution of the paper is to choose proper sliding surfaces. High-order sliding mode controllers have been taken in accordance with the structure of integer order system. Thus, in order for the system to apply more precise calculations, fractional systems should somehow turn to integer order. The sliding surfaces have been selected so appropriately that we can benefit from the structure of integer order controllers for fractional order system. The sliding surface in both controllers has also been the same so as to provide conditions for comparison. The model outputs are reached the desired values using two controllers. Finally, the comparison in simulations indicates that the proposed approach has a great impact on chattering reduction.

Since two-wheeled and the self-balancing robot has a complicated and non-linear structure, its model has some uncertainties. These uncertainties cause that the system has an incorrect solution while using the classic methods for controlling of it. In this paper, a new method based on interval analysis is proposed for modeling the optimal control of the two-wheeled and self-balancing robot with interval uncertain parameters which require only lower and upper bounds of uncertain parameters, with no need to know about probability distributions. Since the system has uncertainties in it, controllability is first analyzed based on interval arithmetic. Afterwards, LQR based method based on Pontryagin principle is utilized to solve the problem. Finally, by solving the interval Ricatti equations, the confidence interval for feedback controller has been achieved. Final results are compared with Monte Carlo method and the results demonstrate the effectiveness of the proposed method.

Recently, power system restructuring, demand response (DR) program and using of distributed generation (DG) are important issues to enhance reliability, power flow continuity and power quality for costumers. In this paper, scheduling of distributed networks with DR program for a 24-hours optimization problem is modelled. The DR program is based on load side participation and in order to solve this optimization problem, a new algorithm called Symbiotic Organism Search (SOS) has been used. Objective functions are system losses and operation costs reduction. After exact definition of the problem, objective functions and constraints, proposed method for short-term scheduling is simulated on a 33-bus standard network with MATLAB software for different scenarios. Simulation results show that adoption of demand response programs with proposed method has desirable performance to reduce losses and costs.

Sliding mode control is an efficient and robust control method widely used in nonlinear systems. Power systems are one of the largest nonlinear dynamic systems which their transient stability analyses have a lot of importance. In this paper, sliding mode control is applied for improving the low frequency oscillations damping of a single machine connected to an infinite bus. The performance of the system is analyzed in normal mode operation, post-fault state, after operation of relays (and opening the breakers in the both ends of the faulty line), and reclosing mechanism which returns the line to service. Here, TCSC is employed as an oscillation damper. TCSC can be considered as a controllable impedance determined by the sliding mode control. In addition, a dynamical observer is proposed for the sliding mode controller. Simulation results demonstrate that, the performance of the power system in damping the low frequency oscillations is improved significantly.

In the modern electrical grid, accuracy and speed of fault clearance are the major challenges which need to be addressed. This paper covers a case study of fault location techniques in electrical transmission network, using numeric relay and offline fault locator. Healthiness of electrical transmission line is ensured using line signature analyzer. Comparative study of online and offline fault location in electrical transmission network has been carried out and the inferences are drawn. On the basis data available it can be said that the frequency of occurrence of single line to ground fault is maximum (about 75%) among various types of faults. Data at 220 kV and 132 kV substations has been collected and analyzed, keeping focus on single line to ground fault. Architecture of Substation Automation System (SAS) using single communication technology based on IEC 61850-8 and IEC 61850-9 is explained. Proposed architecture consisting of numeric meter with Java Compilation Unit (JCU) and Ethernet switch standardized as per IEC 61850 is demonstrated. The Java source code to send indications to output port of numeric meter is included.

Photovoltaic (PV) panels rely on environmental conditions such as irradiation or temperature, and thus they require an interface boost converter. Non-isolated DC-DC boost converters have a lower volume, lower costs and lower power dissipation compared with isolated converters. In this study, a novel high efficiency non-isolated DC-DC boost converter is proposed to be used in PV systems. The converter includes only one semiconductor switch which causes lower switching losses. The main advantages of the proposed converter include low input current ripples, low voltage stress on semiconductor switches, high efficiency and low conduction losses. Moreover, maximum power is achieved from PV panels. A prototype of the proposed converter has been built, and experimental results are presented which explicitly validate theoretical results, suggesting that this boost converter is desirable for PV applications.

We have presented the investigation on the slab of photonic crystals that was made of a honeycomb lattice of silicon embedded in free space. For the simulation of this structure the two-dimensional finite-difference time-domain (FDTD) method was used. This arrangement has shown that with suitable choice of frequency can have negative refraction with an metamedium effect with n=−1. In this conditions, in TE polarization can act as total mirror and in TM polarization can act as superlens. In a certain frequency, this type of photonic crystal structure acts as left handed martial that they were named metamaterials. A wide range effects were studied by this structure. To show these unusual phenomena, we analyzed the contour map and solid model of electric field and magnetic field for a photonic crystals structure. This structure has negative refraction of light, subwavelength lensing effect and 100% reflector. These feathers are in metamaterials that also can be seen in photonic crystals.

FinFETs are the emerging 3D-transistor structures due to strong electrostatic control of active channel by gate from more than one side which was not possible in conventional transistor. FinFET structures with rectangular and trapezoidal shape have been excessively analyzed in literature. The main purpose of this work is to present a FinFET structure with such a compact fin shape that the gate has high controllability over it; and thus reduced short channel effects in comparison to existing structures. Here, FinFET with Broadwell-Y shape, proposed by Intel has been designed and its short channel effects were analysed. Simulations of the designed FinFET have been performed in Technology Computer Aided Design (TCAD) tool. Performance of broadwell-Y shaped FinFET was compared with the existing rectangular and trapezoidal structures for the same input design parameters and it was noticed that Broadwell-Y shaped FinFET outperformed the last two structures in terms of short channel effects. Then the performance of the designed device was optimized using Moth Flame Optimization (MFO) after the network was trained through Artificial Neural Network (ANN). Results obtained from MATLAB were in close agreement with those obtained from TCAD simulations. Output parameters like leakage current (IOFF) of 2.407e-12A, On-Off current ratio (ION/IOFF) of 4.5e06, Subthreshold Swing (SS) of 65.4mV/dec and Drain Induced Barrier Lowering (DIBL) of 37.9mV/V were obtained after optimization. Short channel effects are improved for 20nm gate length as SS is close to ideal value 60mV/dec and DIBL is below 100mV/V which makes this designed structure a good option for applications at nanoscale.

by development of using software of Enterprise Content Management (ECM), necessity of improving electronic correspondence of inter-enterprise is felt more than before in order to enterprise cooperation. Despite existence of some bases for enterprise content management such as ECE protocol still there are some problems such as user intervention, delay, consumption of paper, parallelism, impossibility of tracking correspondence and security problems and possibility of enterprise cooperation is not provided well. Using architecture of service component which has advantages of service-oriented approach such as simplicity, reusability, interoperability and flexibility produces an optimal solution for interoperability between systems and heterogeneous substrates by increasing the agility of integration of web services meanwhile it does not have overload due to services and minimizes costs of development and maintenance. Component service of ECES which is implemented by using architecture of service component supports ECE standards and makes doing electronic correspondence possible between enterprises of Iran. This service component, by addressing the ECE problems described above, can provide organizational collaboration for inter-organizational electronic correspondence, independent of interfacing servers, with higher security and speed, and less error and with capability of tracking correspondence.

This paper presents a simulation of the dynamic voltage stability in power system. In application of modern power system, dynamic assessment of voltage stability is known as basic concept. In order to study dynamic voltage stability in a power system, different dynamic boundaries are defined such as, Hopf bifurcation (HB) boundary. HB point is an oscillatory boundary in power system. For recognition of the bifurcations, it is unavoidable to study the eigenvalues of power system. In spite of this, determination of these eigenvalues needs to dynamic Jacobian matrix of power system and modal analysis that is very time consuming and complex in large systems. Also, different industrial loads (static and dynamic) e.g. induction motors can effect on dynamic voltage stability boundaries. In this paper, we proposed a solution method based on analyzing the eigenvalues of reduced Jacobian matrix and time domain simulation for assessment of dynamic voltage stability. In addition, effects of industrial electrical loads on the small disturbance voltage stability are evaluated by the proposed method. To show the effectiveness of the proposed solution method, it is tested on IEEE 14 bus and New England test systems.

Side-channel attacks are considered to be the most important problems of modern digital security systems. Today, Differential Power Attack (DPA) is one of the most powerful tools for attacking hardware encryption algorithms in order to discover the correct key of the system. In this work, a new scheme based on randomizing power consumption of a fixed-operation logic gate is proposed. The goal of this method is enhancing the immunity of AES algorithm against DPA. Having a novel topology to randomize the power consumption of each Exclusive-NOR gate, the proposed circuit causes random changes in the overall power consumption of the steps of the algorithm; thus, the correlation between the instantaneous power consumption and the correct key is decreased and the immunity of the AES implementations which the key is injected into their process through Exclusive-NOR gates is extremely increased. The proposed method can be used as a general hardening method in the majority of cryptographic algorithms. The results of theoretical analysis and simulations in 90-nm technology demonstrate the capability of the proposed circuits to strengthen AES against DPA. The CMOS area and power consumption overhead is less than 1%.

In this paper, an ultra-high capacity 64-channel optical communication system using a single mode fiber is presented. The proposed system investigates the performance of optical network based on two methods of Duo-Binary modulation format at 10, 20 and 40 Gbps bit rates and distance of 1500 Km. Performance of the proposed under different modulation formats has been studied. The simulated results show that two methods are efficient. Also, the first method of Duo-Binary modulation format in ultra-high capacity optical network at 40 Gbps bit rate has better performance. It is proved that quality factor and bit error rate are function of fiber length.

The semiconductor circuits dissipate energy in the form of binary digits. This dissipation of energy is in the form of power consumption. ALU is complex circuit and is one of many components within CPU. It performs mathematical and bitwise operations. This paper proposes a new low power 8 bit ALU digital circuit for nano scale regions. The proposed ALU has two 4x1 data selectors, 2x4 decoder and an adder circuit as sub modules. The output of 2x4 decoder is connected to 3 input NAND, AND, OR, XOR gates. The low power adder and multiplexer are proposed and it is used for ALU design. With the help of selection lines of multiplexer, the conventional operations of ALU such as logical operations are performed. This proposed ALU caters the need of digital signal processing tools. Present ALU structure is simulated in Linux Computer using Cadence Virtuoso software and implemented in 180nm technology. The proposed ALU has delay of 386.0ps and average power of 677.2uW. The power delay product shows 65.58 % improvement when compared to the conventional 8-bit ALU design.

Diabetes is the costliest gland disease in the world. Given the high rates of diabetic people, the necessity of reducing the costs of early re-hospitalization and increasing re-admissions within 30 days after discharge have drawn the attention of researchers and other health sector authorities to find ways to reduce potential and preventable hospital re-admissions. The objective of this paper is to estimate the risk of re-hospitalization of diabetic patients. In order to achieve this goal, the data were first pre-processed, and then, radial base function neural network combined with colonial competition optimization algorithm was used to estimate the risk of re-hospitalization of diabetic patients. Moreover, this risk was estimated using back propagation neural network algorithm and the radial base function neural network algorithm. The accuracy of the proposed method is 99.91. This method shows higher performance compared to radial base function neural network method and back propagation neural network without feature selection.