Research Articles
Communication
Seyed Mostafa Alaviyan Shahri; Hamid Reza Abutalebi
Abstract
This paper deals with the problem of signal modeling using fractional-order linear prediction. In this research, we obtain the closed-form expression of the optimum sampling frequency of the One-Parameter Fractional-order Linear Prediction (OPFLP) and examine the performance when the fractional order ...
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This paper deals with the problem of signal modeling using fractional-order linear prediction. In this research, we obtain the closed-form expression of the optimum sampling frequency of the One-Parameter Fractional-order Linear Prediction (OPFLP) and examine the performance when the fractional order (alpha) is in (0<=alpha<=2). Our investigation focuses on determining optimum alpha within the individual ranges of 0<=alpha<=1 and 1<=alpha<=2 while considering various influential parameters, such as sampling frequency and environmental interferences. We initiate our study by examining the impact of the sampling frequency, a critical parameter that demands meticulous selection, on the optimal value of alpha. Simulation Results demonstrate that if the sampling rate falls within five to six times the maximum frequency of the signal under scrutiny, the optimal range for alpha resides within 1<=alpha<=2. Conversely, when the sampling frequency exceeds six times the maximum signal frequency, the optimal alpha shifts to 0<=alpha<=1. This observation underscores the crucial relationship between sampling frequency and the appropriate selection of the fractional order alpha for effective OPFLP performance. In the next step, we assess the robustness of OPFLP in handling challenging signal processing tasks, particularly in hands-free speech acquisition applications. We evaluate the model's performance and robustness against environmental interferences in three scenarios: noisy environments, reverberant environments, and noisy-reverberant settings. Simulation outcomes highlight OPFLP's superior robustness compared to second-order LP in handling environmental interferences. Furthermore, our investigations elucidate that noise exerts a more detrimental impact on OPFLP performance than reverberation, emphasizing the nuanced effects of these interferences on the model's efficacy.
Research Articles
Power systems
Farhad Amiri; Mohammad Hassan Moradi
Abstract
: In the context of frequency stability in a two-area microgrid, it is crucial to address the fluctuations in frequency caused by load disturbances. To achieve this, an effective load-frequency control (LFC) system, which serves as the secondary control, must be implemented. However, the presence of ...
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: In the context of frequency stability in a two-area microgrid, it is crucial to address the fluctuations in frequency caused by load disturbances. To achieve this, an effective load-frequency control (LFC) system, which serves as the secondary control, must be implemented. However, the presence of renewable energy sources such as wind turbines and photovoltaic systems adds complexity to the operation of the LFC system due to their inherent uncertainty. To enhance the performance of the LFC system in the two-area microgrid, this paper proposes a reduction in the number of controllers employed, aiming for a less complex structure. Specifically, Model Predictive Control (MPC) is utilized for LFC, and the weight parameters of the MPC controller are determined using Craziness-based Particle Swarm Optimization (CRPSO). The proposed method is compared with alternative approaches, including PID controller optimized with Social Spider Optimization (SSO), Fractional Order Fuzzy PI (FOFPI), and conventional MPC. The effectiveness of the proposed method is evaluated in various scenarios, considering load variations and the presence of distributed microgrid generation resources. The results demonstrate that the proposed method outperforms the other controllers in terms of speed of response, reduction of overshoot and undershoot, and overall complexity. Importantly, the proposed method significantly improves the frequency stability of the two-area microgrid. The simulation and analysis are conducted using MATLAB software, providing a comprehensive understanding of the system dynamics and the performance of the proposed controller.
Research Articles
Power systems
Sasan Pirouzi; Mahmoud Zadehbagheri; Rohollah Rashidi
Abstract
In this article, the robust scheduling of the distribution network is presented considering electric vehicles, distributed generation, and energy storage, in which the energy management of the mentioned elements is considered, and also only one scenario is needed. The proposed deterministic problem is ...
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In this article, the robust scheduling of the distribution network is presented considering electric vehicles, distributed generation, and energy storage, in which the energy management of the mentioned elements is considered, and also only one scenario is needed. The proposed deterministic problem is an optimization problem whose objective function is equal to minimizing energy cost. Also, the limitations of the problem are equal to the power flow equations of the network, the limitations of the technical indicators of the network such as the voltage of the buses and the passing power of the lines, the operation equations of electric vehicles, energy storages, and distributed generation. It is worth mentioning that the mentioned problem is non-linear. In the following, to achieve the global optimal point with a high solution speed, the linear model of the mentioned problem is presented with a very low calculation error. In this research, the uncertainty parameters of the problem are equal to active and reactive loads, energy prices, parameters of electric vehicles, and renewable productions. Finally, to simplify the decision-making of the distribution network operator, a robust model of the mentioned problem was presented. Finally, the proposed problem is applied to the IEEE standard 33-bus radial distribution network using GAMS optimization software, and then the capabilities of the proposed design are evaluated.
Research Articles
Electronics
Bahram Rashidi
Abstract
This paper presents the design and hardware implementation of an efficient and optimal induction heating circuit for induction sealing. The circuit has a low implementation cost, so the proposed system with a simple and efficient structure can cover the needs of this technology field. Here, the focus ...
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This paper presents the design and hardware implementation of an efficient and optimal induction heating circuit for induction sealing. The circuit has a low implementation cost, so the proposed system with a simple and efficient structure can cover the needs of this technology field. Here, the focus is on the implementation process and practical tips in this field. The proposed induction sealing circuit uses zero-voltage switching technology with parallel MOSFETs. In this structure, by using inductors and capacitors with appropriate tolerable current and voltage, it can provide the power and frequency of the output signal applied to the induction coil for various applications. The use of transistors with suitable current capability makes the circuit appropriate for applications that require stronger magnetic fields. In addition, the induction coil has an elliptical structure, which makes it efficient for sealing a wide range of bottles. It is constructed using Litz wire to reduce power loss in the coil. In the presented structure, the frequency of the output signal is equal to 31 kHz, which is suitable for creating an eddy current in the aluminum foil in the bottle caps. The circuit has been tested and investigated and has acceptable sealing for various industries.
Research Articles
Control
Gholam Reza Shahabadi; Majid Reza Naseh
Abstract
A type of converter called Quasi-Z-source converters (QZSC) is becoming more popular due to its benefits, such as operating in a single stage, having smaller components, and maintaining continuous input current and a common ground. This converter is widely used in various applications that need a DC-DC ...
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A type of converter called Quasi-Z-source converters (QZSC) is becoming more popular due to its benefits, such as operating in a single stage, having smaller components, and maintaining continuous input current and a common ground. This converter is widely used in various applications that need a DC-DC converter. The small-signal analysis and linearization method are often used to control the QZSC. The linear model of QZSC does not provide sufficient stability control over a wide range. Sliding Mode Control (SMC) has become widely used for electronic power converters because of their variable structure .This paper presents a SMC for a QZSC with three objectives:1) to achieve stability across a wide range of QZSC; 2) to systematically select the proposed controller coefficients; and 3) to enable tracking of the reference voltage in spite of changes in input voltage, reference voltage, and output load. The simulations have been done with the help of MATLAB/Simulink and show the effectiveness of the proposed method.
Research Articles
Power systems
Morteza Behbahanipour; Seyed Fariborz Zarei; Mohammadhadi Shateri
Abstract
This paper proposes an impedance-based approach for locating short-circuit faults in active distribution networks (DNs). This topic is a crucial task for operators, especially in grids with inverter-based distributed generators (IBDGs). Various methods have been proposed in this research area, including ...
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This paper proposes an impedance-based approach for locating short-circuit faults in active distribution networks (DNs). This topic is a crucial task for operators, especially in grids with inverter-based distributed generators (IBDGs). Various methods have been proposed in this research area, including traveling waves, impedance-based methods, and artificial intelligence (AI) techniques. Among them, the impedance-based scheme provides a simple and efficient feature that could be used in AI-based techniques. In this paper, an enhanced fault localization method based on impedance estimation is introduced. This method comprises two main components: (i) fault distance determination and (ii) faulty section identification. When developing the proposed method, the modeling of inverter-based resources under symmetrical and asymmetrical faults is considered, which includes the impact and behavior of such sources in the proposed approach. Unlike conventional impedance-based methods, the proposed approach does not require network information such as structure, lines, load data, or voltage and current measurements along the feeder at multiple points. The proposed method can be utilized as a feature in AI-based techniques, significantly enhancing accuracy and reducing the complexity of such techniques. To validate the efficacy of the proposed approach, various series of time-domain case studies are performed, in addition to mathematical proofs. The results demonstrate the effectiveness of the proposed scheme in accurately locating faults with varying resistances at different positions in the presence of inverter-based distributed generators.
Research Articles
Control
Mohammed Yakoob; Mina Salim; Amir A. Ghavifekr
Abstract
Regulating voltage and current signals in microgrids (MG) is essential to ensure stability, optimize power quality, support grid integration, enhance operational efficiency, and promote safety within the system. This paper introduces a novel Linear Matrix Inequalities (LMI)-based approach aimed at regulating ...
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Regulating voltage and current signals in microgrids (MG) is essential to ensure stability, optimize power quality, support grid integration, enhance operational efficiency, and promote safety within the system. This paper introduces a novel Linear Matrix Inequalities (LMI)-based approach aimed at regulating voltage and current signals within microgrids through the utilization of sliding mode control. The MG under examination in this paper is composed of a voltage source inverter (VSI) for DC to AC voltage conversion, a filter to ensure sinusoidal signal quality, and an array of loads, including those with uncertain characteristics. The objective of this study is to regulate the output voltage and current in a short period of time in the presence of diverse loads. By promptly adjusting voltage and current levels, the microgrid can effectively accommodate fluctuations in demand and maintain optimal performance under changing conditions. The presented controller consists of two parts: a state feedback gain calculated from the LMI and a sliding mode-based controller to maintain system stability. This controller is intended to reject disturbances, track reference signals, and minimize steady-state errors in a limited time. The satisfactory performance of the microgrid will have a significant impact on various parameters, such as frequency, active power, reactive power, and power factor. Simulating the voltage source inventor and presenting numerical results demonstrate the effectiveness of the proposed controller to provide high robustness against uncertainty and nonlinear loads while maintaining system stability.
Research Articles
Industrial Electronics
Mohammad Ali Heydari; Mahdi HassanniaKheibari; Gholamreza Sadeghi
Abstract
Active power filters (APFs) play a vital role in reducing the current harmonics and improving power quality. This work studies a shunt APF (SAPF) based on the three-phase voltage source converter (VSC). This paper investigates the new robust control approach using error dynamics. Stable first-order error ...
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Active power filters (APFs) play a vital role in reducing the current harmonics and improving power quality. This work studies a shunt APF (SAPF) based on the three-phase voltage source converter (VSC). This paper investigates the new robust control approach using error dynamics. Stable first-order error dynamics are considered when designing the control inputs. Three control inputs are obtained to control the currents at any phase by choosing and optimizing the appropriate parameters. This strategy is also simple to implement in practical applications because it is the same as the proportional-derivative controller design. In addition, the new control method can be utilized for any system with low dynamic information so that the destructive effects of lumped uncertainties in the output channels of the SAPF can be alleviated. The minimum voltage and current measurements are used to control the SAPF, and the grid current harmonics will be reduced by achieving the stabilization of tracking error dynamics. Some numerical simulations are performed by MATLAB software to confirm the proposed method.
