Research Articles
Control
Mahmood Nazifi; Mahdi Pourgholi
Abstract
The consensus of Cyber-Physical Power Systems (CPPSs), where generators agree on common desired rotor angles and speeds, is vital for maintaining system stability and efficiency. This study explores this consensus using fractional-order multi-agent systems, offering advantages over traditional methods. ...
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The consensus of Cyber-Physical Power Systems (CPPSs), where generators agree on common desired rotor angles and speeds, is vital for maintaining system stability and efficiency. This study explores this consensus using fractional-order multi-agent systems, offering advantages over traditional methods. CPPSs often encounter issues like faults, uncertainties, disturbances, and cyber-attacks. To address these, a new Adaptive Fractional-Order Sliding Mode Controller (AFOSMC) is proposed, designed to achieve consensus despite unknown nonlinear functional upper bounds characterizing system perturbations. The AFOSMC uses stable adaptive laws to determine these unknown coefficients, ensuring robust performance even under adverse conditions. It outperforms conventional Integer-Order counterparts by reducing chattering and enabling faster convergence during the initial phase of CPPS operations. The AFOSMC also ensures finite-time convergence to the sliding surface, enhancing system responsiveness and stability. The controller's stability is rigorously proven using Lyapunov's theorem. Finally, extensive simulations demonstrate the practical benefits of the AFOSMC, and comparisons with recent research highlight its superior performance in robustness and efficiency.
Research Articles
Control
Fatemeh Soleimannouri; Saeed Khorashadizadeh; Mohsen Farshad; Naser Mehrshad
Abstract
In this research, an adaptive fuzzy controller is presented to regulate the blood glucose level of type 1 diabetic patients in the presence of input saturation. This controller along with an adaptive anti-windup compensator is considered to deal with the uncertainty of the Bergmann minimal nonlinear ...
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In this research, an adaptive fuzzy controller is presented to regulate the blood glucose level of type 1 diabetic patients in the presence of input saturation. This controller along with an adaptive anti-windup compensator is considered to deal with the uncertainty of the Bergmann minimal nonlinear model parameters as well as the input saturation. Anti windup compensator is designed to prevent to saturation problems as hyperglycemia or hypoglycemia in regulating the blood glucose level of type 1 diabetes patients. The Bergman minimal model is used to mathematically model type 1 diabetes, depicting the dynamic behavior of the human body's blood glucose-insulin system. In the first step, the stability of the closed-loop system has been theoretically investigated and proved from the point of view of Lyapunov's theory. Next, to evaluate the effectiveness of the proposed method in regulating blood glucose levels, the proposed control system has been implemented in the presence of meal disturbances using the Simulink environment of MATLAB software. The implementation results show a lower control effort and less convergence time of the proposed method compared to the existing methods.
Research Articles
Electronics
Hosein Malekpoor; Mehdi Hamidkhani
Abstract
A compact microstrip antenna by applying a parasitic artificial magnetic conductor (AMC), is proposed for facilitating 4G and 5G wireless communications. The antenna design includes microstrip dipoles fed by a T-shaped feedline. Notably, the antenna achieves a measured bandwidth of 5.32-6.73 GHz (with ...
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A compact microstrip antenna by applying a parasitic artificial magnetic conductor (AMC), is proposed for facilitating 4G and 5G wireless communications. The antenna design includes microstrip dipoles fed by a T-shaped feedline. Notably, the antenna achieves a measured bandwidth of 5.32-6.73 GHz (with S11≤ -10 dB). To enhance performance, a proposed parasitic AMC reflector is integrated into the antenna structure. Incorporating an 8×8 AMC array, the antenna extends its -10 dB measured bandwidth from 4.55 to 6.83 GHz, catering to both 4G and 5G communication standards. Comparative analysis with an antenna lacking AMC reveals a reduced size of 34%, alongside a notable gain of 8 dBi and uni-directional radiation patterns. The efficiency and gain of all elements are approximately 90% and 8 dBi, respectively. Moreover, the introduction of an AMC unit cell, well-founded on a parasitic patch, resonates at 6.12 GHz with a bandwidth extending from 5.25 to 7.15 GHz. Furthermore, the offered equivalent transmission line model of the antenna with the AMC is demonstrated, yielding desirable results. This model accurately predicts the input impedance of the antenna with AMC across a broad frequency band ranging from 4.61 to 6.72 GHz. This comprehensive study demonstrates the effectiveness and versatility of the offered model in characterizing the operating band's behavior of the antenna across a wide frequency band to facilitate its design and optimization for various applications.
Research Articles
Industrial Electronics
Jasem Shahsevani; Reza Beiranvand
Abstract
Efficient and versatile charging solutions are essential for modern applications requiring portable energy systems. This paper presents a novel portable charger powered by an isolated split-core current clamp, enabling direct charging from power lines. The system utilizes inductive coupling to draw AC ...
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Efficient and versatile charging solutions are essential for modern applications requiring portable energy systems. This paper presents a novel portable charger powered by an isolated split-core current clamp, enabling direct charging from power lines. The system utilizes inductive coupling to draw AC current from these lines, which is then regulated to a precise voltage for battery replenishment. The proposed design features an interleaved resonant topology with a semi-active rectifier, achieving high efficiency and adaptability to a wide range of input voltages. This architecture supports a variable DC bus voltage, enabling the resonant converter to operate optimally near its resonant frequency for maximum performance. To ensure a lightweight and efficient design, the converter eliminates traditional transformers, incorporating a capacitive element within the resonant network for galvanic isolation. A cascaded dual-control strategy in the interleaved structure ensures precise voltage regulation. Designed to be compatible with 1-6 cell Li-Ion batteries, the charger offers extensive versatility. Experimental results from a 2.5-200 W prototype, with an output voltage range of 4.2-25.2 V, demonstrate a peak efficiency of 94%, validating the effectiveness of the proposed charger for grid-connected applications.
Research Articles
Power systems
Hamed Shadfar; Hamid Reza Izadfar
Abstract
One of the main components of a power transformer is the transformer insulation system, namely, transformer insulation oil and transformer insulation paper. Any failure can cause the transformer to fail temporarily or permanently. As a result, regular and non-destructive monitoring of transformers is ...
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One of the main components of a power transformer is the transformer insulation system, namely, transformer insulation oil and transformer insulation paper. Any failure can cause the transformer to fail temporarily or permanently. As a result, regular and non-destructive monitoring of transformers is of particular importance for early detection and prediction of any faults. Frequency response analysis (FRA) is known as a high-accuracy, fast, economical, and non-destructive method for diagnosing the condition of a transformer, which can be used independently or as a complementary method to ensure the results of other diagnostic tests and based on the operational conditions of the transformer, it can be implemented in two methods, online and offline. This paper provides an in-depth discussion of measuring and interpreting FRA results and the ability of this method to detect and locate power transformer faults, especially insulation faults, which have been given less attention in the past. The information confirmed in this survey is expected to provide an important roadmap for future research in monitoring the condition of transformer insulation systems
Research Articles
Control
Seyedeh Mahsa Zakipour Bahambari; Saeed Khankalantary
Abstract
This article focuses on the design of a controller for quadcopter position control, which is then used to organize a group of quadcopters into a specific formation. Initially, PID controllers are developed to manage all output variables of the quadcopter systems efficiently. Subsequently, a constrained ...
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This article focuses on the design of a controller for quadcopter position control, which is then used to organize a group of quadcopters into a specific formation. Initially, PID controllers are developed to manage all output variables of the quadcopter systems efficiently. Subsequently, a constrained tube-model predictive control (Tube-MPC) approach is implemented to regulate the system's position, comparing its performance to that of the tube-MPC controller. The article also explores the coordination of a group of six quadcopters, focusing on achieving a predefined formation that maintains the desired shape. Three different scenarios are examined to control the formation, assessing how each approach influences the arrangement and coordination of the quadcopters. The dynamics of the system's control are crucial for effective operation in multi-agent systems. Moreover, the configuration of the quadcopters is influenced by each quadcopter's internal controller, ensuring accurate formation and tracking. This study underscores the significance of sophisticated control strategies in improving the performance and coordination of multiple quadcopter systems.
Research Articles
Control
Mir Mohammad Khalilipour; Farhad Shahraki; Jafar Sadeghi; Kiyanoosh Razzaghi
Abstract
Objective: The objective of this research is to optimize the crude distillation unit (CDU) in oil refineries by reducing energy consumption and improving operational efficiency through the application of a Proportional-Integral-Plus (PIP) control system within a Non-Minimal State Space (NMSS) framework. ...
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Objective: The objective of this research is to optimize the crude distillation unit (CDU) in oil refineries by reducing energy consumption and improving operational efficiency through the application of a Proportional-Integral-Plus (PIP) control system within a Non-Minimal State Space (NMSS) framework. Material and Method: Simulations of the CDU were carried out using Aspen Plus for modeling the distillation process and MATLAB for implementing the PIP control structure. The controller was tuned by an economic cost function, optimizing key parameters such as furnace duty, side-draw rates, and condenser heat removal. The PIP control system was compared to traditional control methods, with performance evaluated under various disturbances, including feed rate, temperature, and composition changes. Results: The PIP control strategy significantly improved the CDU’s performance, reducing operating costs by up to 100% compared to traditional control methods optimized by the Integral of Time-weighted Absolute Error (ITAE). The PIP system demonstrated superior disturbance handling and energy efficiency while maintaining product quality. Conclusion: The findings indicate that the PIP control system is a highly effective tool for optimizing energy consumption and process stability in modern refineries, especially under fluctuating operational conditions. Its application could lead to substantial cost savings and improved efficiency in CDU operations.
Research Articles
Power systems
Reza Ghanizadeh; Hamed Azadrou
Abstract
Bearing-less induction motors (BLIMs) are suitable candidates for high-speed applications but suffer from low torque density and complex control issues due to the interaction of torque and levitation forces. To address these challenges, this paper presents a new control strategy that combines vector ...
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Bearing-less induction motors (BLIMs) are suitable candidates for high-speed applications but suffer from low torque density and complex control issues due to the interaction of torque and levitation forces. To address these challenges, this paper presents a new control strategy that combines vector control and direct torque control (DTC) for torque management, alongside a novel force control method based on finite element analysis (FEA). The proposed approach minimizes interference between torque and force magnetic fields by employing a parallel winding structure and distinct control units for torque and force. Simulation results demonstrate that the proposed method significantly reduces torque ripple and improves steady-state performance compared to conventional vector control and DTC. Furthermore, the force control unit outperforms a dual field-oriented control (FOC) method in regulating rotor position, offering better suspension force control and faster stabilization. This work contributes to the development of more efficient control strategies for BLIMs, enhancing their performance in industrial applications.
Research Articles
Optimization
Sadegh Etedali
Abstract
This paper proposes three techniques aimed at enhancing the seismic performance of base-isolated tall buildings through uniform deformation of the superstructure. The first and second methods focus on generating a uniform modal shape and an even distribution of seismic loads across the floors, while ...
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This paper proposes three techniques aimed at enhancing the seismic performance of base-isolated tall buildings through uniform deformation of the superstructure. The first and second methods focus on generating a uniform modal shape and an even distribution of seismic loads across the floors, while the third method seeks to minimize the standard deviation of story drifts. For these purposes, an optimization procedure based on a gas Brownian motion optimization (GBMO) algorithm is defined. Simulation results, compared to those for a 20-story reference base-isolated structure, demonstrate that these techniques effectively reduce maximum floor displacement, particularly in the upper levels of the studied buildings. The proposed methods show clear advantages in lowering maximum floor drift, a critical factor in seismic damage. Specifically, methods 1 and 3 resulted in significant reductions in maximum floor drift, ranging from 30% to 80% in the upper floors. Additionally, these methods led to a reduction of 10% to 15% in maximum acceleration and seismic forces on the upper floors, while a slight increase was observed in the lower floors. Among the methods, method 1 exhibited the best overall performance, yielding average reductions of 6.65%, 32.65%, and 0.88% in maximum floor displacement, drift, and acceleration, respectively, when compared to the reference base-isolated structure. While methods 2 and 3 resulted in only modest reductions in displacement and acceleration, they were effective in significantly lowering maximum floor drift.
Research Articles
Industrial Electronics
Hayder Ameer Hasan Al-Ameedee; Majid Delshad; Nadheer Abdulridha Shalash; Bahador Fani
Abstract
In this study, a new converter featuring an auxiliary circuit configuration is presented, designed to facilitate soft switching conditions while minimizing the number of components used. This auxiliary circuit is innovatively developed to achieve zero voltage switching (ZVS) and effectively recover snubber ...
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In this study, a new converter featuring an auxiliary circuit configuration is presented, designed to facilitate soft switching conditions while minimizing the number of components used. This auxiliary circuit is innovatively developed to achieve zero voltage switching (ZVS) and effectively recover snubber energy to the input side, thereby enhancing the converter efficiency. Furthermore, the deliberate integration of coupled-inductors into the converter's design significantly boosts its gain while reducing voltage stress on the switching components. The modular architecture of the auxiliary circuit allows for the addition of circuit branches and an increase in power capacity without requiring extra components for its auxiliary circuit. To evaluate the performance of the proposed converter, extensive simulations were performed using PSPICE software, along with the construction of a laboratory prototype capable of operating at 170W. The alignment between the experimental results and simulation data strongly supports the theoretical analysis, illustrating the converter's potential for efficient power conversion in renewable energy systems.
