فصلنامه روشهای هوشمند در صنعت برق
پیاپی 53 (بهار 1402)

By increasing use of new energy to reduce the negative effects of burning fossil fuels to supply electricity, the need for power electronic converters have become very important. Due to sudden changes in load or input voltage level, the converter used as a voltage regulator in a certain range of output voltage changes should quickly return to its reference value, which should analyze the dynamic behavior of these converters and the speed of its dynamic response to any interference is discussed. Because the initial boost converter has a delay in its transfer function due to the right half plane zero, it is possible to use structures to eliminate this delay. The use of coupled inductor in non-insulated structures is one of the structures that can be repaired in this field, which in addition to removing right half plan zero of the transfer function, increases voltage gain, reduces voltage stress on circuit semiconductors. In this paper, a new coupled inductor structure is proposed to remove the right half plan zero. The new structure will be accompanied by an increase in gain, but the voltage stress on the switch is limited, and on the other hand, due to the position of the coupled inductor, the input current for this structure will be minimized.

In this paper, the robust planning of the islanded hybrid system (IHS) to create an integrated system with wind turbine, photovoltaic, diesel generator, stationary (battery) and mobile (electric vehicles) storages is presented. The proposed scheme minimizes the planning cost (including construction, maintenance, and operation) of the mentioned sources and storages, and environmental pollution level. This problem is constrained to operation and planning model of the different sources and storages, and power balance constraint in IHS. The proposed scheme is formulated in the Pareto optimization framework based on method of the summation of weighted functions. Also, the bounded uncertainty-based robust optimization (BURO) is used to model the uncertainties of load, renewable power, and energy of mobile storage. Then, the hybrid evolutionary algorithm according to composition of Krill Herd Optimization (KHO) and Grey Wolf Optimization (GWO) algorithms obtains an optimal solution including low standard deviation in the final response. Finally, it is seen that the proposed scheme has a suitable capability in the planning of the proposed system according to economic and environmental viewpoints based on obtained numerical results.

As an important branch of the Internet of Vehicles (IoV), vehicle positioning has drawn extensive attention. Traditional positioning systems based on a global positioning system incur long delays, and may fail due to obstructions. In this article, we propose an auxiliary positioning architecture, whose core is to estimate the direction of arrival (DOA) of signals from landmarks, such as wireless access points, utilizing a sensor array in the vehicle. Due to space limitations, the array may be placed in an arbitrary geometry and may suffer from mutual coupling effects, and it is possible that the effect of mutual coupling between the array elements greatly reduces the independence of the elements of the array, and this effect involves the interaction of each element with its nearby objects. Mutual coupling in antenna arrays can critically degrade the performance of signal processing algorithms. In this paper, a new and accurate form of mutual impedance matrix (MIM) is used to compensate for the effect of mutual coupling in uniform linear arrays (ULA) by a new method based on solving the boundary value problem for all array elements. By using the MIM in the DOA estimation algorithms, these algorithms will be robust to the mutual coupling effect. The simulation results confirm the performance improvement of the proposed DOA estimation algorithm. The proposed architecture can obtain robust self-localization with existing vehicular ad hoc networks, and it can collaborate with other positioning systems to provide a safe driving environment.

In this paper, an improved online method for simultaneous estimation of parameters and fault location in transmission lines based on Phasor Measurement Units (PMUs) installed on both sides of the transmission line is proposed. Unlike offline methods, the proposed method does not depend on the geometric characteristics of the lines, the fault resistance and the impedance of the equivalent Thevenin sources. The most important application of line modeling is to estimate the thermal rating of transmission lines, which limits the power transmission capacity. Offline methods cause part of the power transmission capacity to be unused and create unrealistic congestion in the transmission system. Therefore, the estimation must be determined in a way that is online and has the appropriate accuracy and speed. Calculating the thermal rating is a complex task that requires estimating the parameters of the lines, calculating the temperature of the lines and determining the climatic conditions of the environment around the studied lines. Therefore, a new method based on a combination of direct conductor temperature monitoring method and method based on climatic conditions is proposed in this paper. In this method, first, the parameters of the transmission line are estimated and then using these parameters and the weather conditions of the desired line, the thermal rating is calculated online. In this paper, the Nonlinear Least Squares (NLS) method is used to perform the process of simultaneously estimating the fault location and line parameters. The simulations were performed in the MATLAB software environment on a standard series capacitor-compensated transmission lines. The simulation results show that the proposed method has high accuracy and speed and can play a significant role in increasing the speed of line repairs and system reliability and reducing social and economic losses.

Due to the different distances and complexity of micro-grids, the lines impedance varies between the feeders of the distributed generation and the loads. Therefore, conventional droop control method does not have good efficiency in power distribution between distributed generation (DG) units. Generally, due to simplification, the impedance of the lines is not considered in a complex. The stated conditions greatly reduce the accuracy and speed of the dynamic response of the control system. In this paper, harmonic compensation, voltage and frequency control of micro-grid with adaptive virtual impedance method based on proportional power distribution are presented. In the proposed method, reducing the error coefficient of active power and reactive power, control of voltage and currents’ harmonic in two modes of connection to the main grid and islanded, as well as voltage and frequency control for optimal operation of the micro-grid is presented. The proposed method, without the need to update the impedance information of the feeders, has the capability of optimal operation and power distribution under different operating conditions, taking into account the complex impedance. To validate, the proposed method is simulated in MATLAB/Simulink software environment and the results are presented along with stability and sensitivity analysis.

In the last decade, optical integrated circuits, including modulators, have made significant progress in optical communications, imaging, and sensors. Among the active materials used in modulators, graphene and indium tin oxide (ITO) are some of the suitable options among the active materials for modulation action due to their epsilon-near-zero (ENZ) characteristics, speed, and considerable response. In this paper, by applying direct coupling of light, the structure of plasmonic modulator in three-dimensional mode has been designed. And by changing the thickness of ITO, HfO2 (hafnium oxide) layers and waveguide width, the structure is optimized. Optimization thickness of 3 nm for ITO, 5nm for HfO2 and 280nm for waveguide width is achieved. The results of three-dimensional simulations of this paper with appropriate coupling show that the insertion loss (IL) of three-dimensional mode have not changed and the extinction ratio (ER) of the modulator has been slightly reduced in comparison with two-dimensional mode .On the other hand, appropriate and optimal coupling has no effect on energy consumption.Three-dimensional results show that the proposed plasmonic modulator can achieve an extinction ratio of 13.9 dB, an insertion loss of 2.9 dB, modulation speed of 140.9 GHz and a very low power consumption of 1.51 fj/bit for a 1µm length of the modulator, at 0.5 V voltage and a wavelength of 1.55 µm. Our design demonstrates a considerable reduction in energy consumption and improvement in extinction ratio compared to previous works. Also, for a 2 µm length of the modulator, an extinction ratio of 27.76 dB, an insertion loss of 5.68 dB, modulation speed of 70.14 GHz and power consumption of 2.88 fj/bit is achieved.

The use of new physical layer security approaches such as intelligent reflective surfaces as well as the use of existing capabilities in the mobile network such as the participation of network users as network partners are solutions that can be very effective in the next generation of mobile telecommunications to improve and increase the total Secrecy Rate in the physical layer.The proposed solution for improving the secrecy rate of the transmitted signal in the physical layer performed by closed-form solution to the described system. In this paper, we analyzed a network consisting of a gNB, two users, an IRS and an eavesdropper in an environment full of obstacles. Using Simulations, we evaluate our solution mathematically and investigate the effect of the eavesdropper location on the total secrecy rate. Also, the analysis and simulation of secrecy rate for the proposed network is performed by taking into account practical network considerations such as changing the location of the Eavesdropper in the network. In addition, the impact of changing the number of elements of smart surface arrays has been analyzed. The numerical results reveal that increasing IRS elements can enhance the ergodic secrecy rate, the reason is that increasing of IRS elements can focuses the main beam of data signal on the first user which increase secrecy rate. Finally, we compare the performance of the OMA and NOMA techniques in the proposed system model. We show that the NOMA technique provides 50% more ergodic secrecy rate compared to the OMA technique.

In this paper, a comprehensive energy management model is proposed in order to the operation of a ‎modified 33-radial bus distribution system, in the presence of smart homes. In the proposed model, ‎smart home customers are able to participate in a demand response (DR) program and their comfort ‎index is also considered as the main constraint. The model also considers uncertainties related to the ‎load demand, the generation of renewable energy resources and electricity price. The Monte Carlo ‎simulation method and the ScenRed tool are utilized to generate and reduce the scenarios, respectively. ‎In order to mimic the actual operating conditions, in the simulation, the seasonal variations of load ‎and generation are considered and the operation problem is solved for four seasons.‎‏ ‏A linear AC ‎power flow is also used in the model. Finally, the problem is modeled as a mixed-integer linear ‎programming (MILP) problem and solved by the CPLEX solver in GAMS software. The simulation ‎results demonstrate that the model proposed in this study is a comprehensive framework for the ‎operation of distribution systems in the presence of smart homes, which not only reduces operating ‎costs but also increases the consumers’ comfort index.‎

Energy management in microgrids is done with different goals such as reducing operation costs. In this approach, the microgrid operator tries to manage energy in order to supply the energy required by consumers at the lowest possible cost, by determining the amount of energy generation by each of the available energy sources. These resources can generate electrical, thermal or combined energy. In this paper, energy and structure management in microgrids have been done with objectives such as reducing operation costs, reducing environmental pollution and improving technical indices such as reducing real power losses. For this purpose, it has been used from options such as demand response programs, storage devices, distributed generation resources such as combined heat and power generators, renewable sources such as wind and photovoltaic units and feeder reconfiguration. In this paper, the genetic algorithm, which is one of the most valid meta-heuristic algorithms, is used to solve the optimization problem. Numerical results show the efficiency of the proposed model.

In this paper, Blood Glucose control in type 1 diabetic patients in the presence of structured and unstructured uncertainties is studied. In order to increase the effectiveness of the proposed control approach, assumed that all the dynamics describing the regulation of Blood Glucose in type 1 diabetic patients are completely unknown. Based on the fuzzy approximation function, which is equipped with the adaptive algorithm and employing the approach of reducing the number of adaptive fuzzy parameters, the unknown dynamics of the Bergman model approximated. Then, based on the feedback linearization control approach and robust adaptive compensator, the design of feedback linearization robust fuzzy controller to regulate Blood Glucose in type 1 diabetic patients in the presence of meal is studied for the first time. Using Lyapunov theory, it is shown that all signals of the closed-loop system are uniformly ultimately bounded and the Blood Glucose of diabetic patients converges to the neighborhood of the desired value. Finally, the simulation results show a good controller performance in reducing effect of the meal disturbance, and robustness against uncertain dynamics and meal estimation errors. Moreover, in comparison with some existing results, a good performance of the introduced controller in controlling Blood Glucose of diabetic patients (i.e., keeping Blood Glucose in allowed range 70-120 mg/dl) validated.