Research Articles
Industrial Electronics
Babak Fathipour; Ebrahim Babaei; Ramin Kheyri; Samuel Nii Tackie
Abstract
In this paper, a single-phase boost AC-AC converter with inherent commutation and step-changed frequency operation is proposed. Distinct from conventional AC-AC converters, the proposed design achieves output voltage regulation utilizing one high-frequency switch. The inherent commutation feature of ...
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In this paper, a single-phase boost AC-AC converter with inherent commutation and step-changed frequency operation is proposed. Distinct from conventional AC-AC converters, the proposed design achieves output voltage regulation utilizing one high-frequency switch. The inherent commutation feature of the converter negates the necessity for additional snubber circuits or complex commutation strategies, thereby simplifying the control method for adjusting the output voltage amplitude and frequency. The continuous input current of the proposed converter eliminates the requirement for a bulky LC filter. A straightforward and adaptable switching strategy is implemented to produce output frequency variations. The approach of preventing the conduction of the body diode in power MOSFETs mitigates issues associated with poor reverse recovery, enabling high-speed switching. The operating principles of the converter are elucidated across various modes of operation, with key equations derived and analyzed. To substantiate the validity of the proposed design, simulation results obtained using PSCAD/EMTDC software at frequencies of 25Hz, 50Hz, and 100Hz are presented.
Research Articles
Industrial Electronics
Reza Hazratian; Ebrahim Afjei
Abstract
This paper introduces a high-gain, non-isolated DC-DC converter featuring a single switch and a straightforward driving circuit. The proposed topology employs a super-lift Lou converter beside inductor-based and capacitor-based voltage multiplier cell to enhance the voltage lift technique. The voltage ...
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This paper introduces a high-gain, non-isolated DC-DC converter featuring a single switch and a straightforward driving circuit. The proposed topology employs a super-lift Lou converter beside inductor-based and capacitor-based voltage multiplier cell to enhance the voltage lift technique. The voltage gain is capable of exceeding tenfold at low duty cycles. The input current is kept continuous to decrease the current stress of the input filter capacitor and the current stresses are less than the input current. Moreover, the voltage stresses remain below the output voltage, notably, the maximum value on the components is kept under half of the output voltage, marking a significant advancement for high-output voltage applications. Additionally, a common ground for the load and input source is established and the electromagnetic interference (EMI) noise issues are managed. The proposed topology is discussed in the ideal and non-ideal modes. Furthermore, the converter’s required relations are discussed in the continuous and discontinuous conduction modes (CCM & DCM). Then the suitable applications are discussed. Finally, this topology is highly recommended for high-intensity discharge (HID) lamps, supported by experimental results from a prototype with a 12 V input, 312 V output, 0.1 A output current and a 50 percent duty cycle.
Research Articles
Control
Yunes Mohamadi; Maryam Alipour; Akbar Hashemi Borzabadi
Abstract
The present paper proposes a novel numerical approach for approximating solutions to optimal control problems with parabolic constraints. Utilizing Laguerre polynomials as a novel basis set, a method was developed to address a class of this problem. The employment of these basis functions in conjunction ...
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The present paper proposes a novel numerical approach for approximating solutions to optimal control problems with parabolic constraints. Utilizing Laguerre polynomials as a novel basis set, a method was developed to address a class of this problem. The employment of these basis functions in conjunction with the collocation method facilitates the transformation of optimal control problems governed by parabolic constraints into a system of nonlinear algebraic equations. The present study proposes an efficient discretization and transformation of complex optimal control problems governed by parabolic equations into lower-dimensional algebraic systems by leveraging the unique properties of Laguerre polynomials.Convergence analysis has been demonstrated to ascertain the optimal value approximations of the proposed method. In order to provide a comprehensive illustration of the reliability and applicability of the proposed method, two illustrative examples are presented. The findings underscore the efficacy and precision of the implemented methodology. This work makes a significant contribution to the field by offering a robust framework for solving complex parabolic control problems, thereby demonstrating the potential of spectral methods in the context of optimal control theory.
Research Articles
Power systems
Hamid Reza Sezavar; Saeed Hasanzadeh
Abstract
Insulator pollution levels are critical for ensuring the operational stability and safety of power transmission systems. Traditional methods for detecting pollution are often invasive, inaccurate, and time-consuming. To address these issues, this study investigates the application of Artificial Intelligence ...
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Insulator pollution levels are critical for ensuring the operational stability and safety of power transmission systems. Traditional methods for detecting pollution are often invasive, inaccurate, and time-consuming. To address these issues, this study investigates the application of Artificial Intelligence (AI), specifically Gradient Boosting Machines (GBM), to classify insulator pollution levels based on Partial Discharge (PD) characteristics. We utilize a combination of time-domain and frequency-domain features extracted from PD signals to train a predictive model. The results indicate that the proposed model achieves a high classification accuracy, averaging between 92% and 95% across various contamination levels. Furthermore, the study analyzes the model's sensitivity to environmental factors, including humidity and Hydrophobicity Class (HC), revealing important insights that could influence classification performance. By employing this AI-driven approach, we aim to significantly enhance the efficiency of power grid maintenance, ultimately contributing to the long-term stability and reliability of transmission systems. The findings from this research underscore the potential of AI in revolutionizing pollution assessment methods and optimizing maintenance practices in power infrastructure.
Research Articles
Control
Nima Rajabi Namini; Ramezan Havangi; Amir Hossein Abolmasoumi
Abstract
An earthquake is a sudden and destructive natural disaster that often results in unpredictable damage to human life and property. Investigating the effects of earthquakes on buildings and enhancing the seismic performance of structures is a crucial approach for mitigating severe damage ...
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An earthquake is a sudden and destructive natural disaster that often results in unpredictable damage to human life and property. Investigating the effects of earthquakes on buildings and enhancing the seismic performance of structures is a crucial approach for mitigating severe damage during such events. One effective tool in testing the resistance of structures against earthquakes is the use of shaking tables. In this paper, the stabilization and control of earthquake simulator using a fuzzy sliding mode controller (FSMC) and adaptive unscented Kalman filter (AUKF)and adaptive extended Kalman filter (AEKF) is presented. These filters employ a recursive technique to effectively adjust the noise covariance by utilizing an adaptation method known as the steepest descent. In the proposed approach, the shaking table states are estimated using an accelerometer, encoder, and camera. These estimated states are then utilized by the AEKF/AUKF to stabilize and control the closed-loop system. A fuzzy sliding mode controller is designed to track the reference input, and eliminate external disturbances and noise. In the control of sliding mode, the occurrence of chattering in the control input is unavoidable. To mitigate this undesired chattering phenomenon, a fuzzy inference mechanism has been employed. The image processing approach has been utilized to measure the displacement online using the camera. The advantages of using the camera include not requiring direct contact with the table, as well as offering a low price and good accuracy.
Research Articles
Power systems
Mahdi HassanniaKheibari; Zivar Rigi
Abstract
As power systems rapidly expand and the demand for uninterrupted power supply to network loads increases, ensuring the safe and stable operation of these systems has become crucially important. However, conducting dynamic stability assessments with detailed dynamic models is nearly impossible in today’s ...
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As power systems rapidly expand and the demand for uninterrupted power supply to network loads increases, ensuring the safe and stable operation of these systems has become crucially important. However, conducting dynamic stability assessments with detailed dynamic models is nearly impossible in today’s complex power networks. The introduction of Phasor Measurement Units (PMUs) has paved the way for new stability evaluation techniques that rely on real-time measurement data. A common limitation of most measurement-based techniques is their vulnerability to noise in the data. While some newer methods offer improved noise resistance, they are often hindered by high computational demands and slow processing times, limiting their practical use. This paper developed a measurement-based method that uses power spectral density (PSD) and cross-spectral density (CSD) to achieve a more precise estimation of low-frequency oscillations in power systems. Simulation results on the IEEE 14-bus and 39-bus test systems, tested under both noisy and noise-free conditions, show that the proposed method yields more accurate frequency and oscillation shape estimates, even when measurement noise is present. Additionally, the Prony algorithm, a well-known measurement-based method, is also implemented, and its high sensitivity to noisy data is demonstrated.
Research Articles
Communication
Motahareh Arezoomandan; Shahram Mohanna; Ahmad Bakhtiyari Shahri
Abstract
A new compact Ultra-Wide Band (UWB) arch shaped wide-slot antenna has been implemented for Microwave Imaging (MI) of breast cancer. It includes a fork-shaped strip and an arched slot ground, has a compact size of 16×20mm with a height of 1mm. The arched slot in the ground plate enhances the impedance ...
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A new compact Ultra-Wide Band (UWB) arch shaped wide-slot antenna has been implemented for Microwave Imaging (MI) of breast cancer. It includes a fork-shaped strip and an arched slot ground, has a compact size of 16×20mm with a height of 1mm. The arched slot in the ground plate enhances the impedance bandwidth and the gain of the antenna. It has a bandwidth of 3.7 GHz to 18 GHz, that covers WLAN (5.4 GHz), X band (8-12 GHz), and Ku band (12-18 GHz) and having gain of 2.7 dBi to 6.3 dBi in the frequency ranges. The fidelity factor was computed for both E-plane and H-plane scenarios, indicating range of 0.922 to 0.975 for the E-plane across all angles. It has a small size, simple design, less signal distortion, a high gain of 6.3 dBi, the fractional bandwidth percentage of 131%. and efficiency of 93.7% at 6 GHz. It has reliable performances in terms of the fidelity factor at all angles compared to the most recent works. A microwave imaging simulation for breast tumor detection is performed to detect changes in the backscattering signal in the presence or absence of a tumor with a high dielectric inclusion. S11 is quite high when measured in front of the breast model and a noticeable difference in S21 exists between the scenarios with and without a tumor in the breast model. A significant variation in the transmission parameter exists across the entire frequency range, the scenarios with and without the presence of the tumor.
Research Articles
Communication
Mohammad M. Fakharian
Abstract
This paper presents an optimized microwave rectifier circuit that integrates various couplers to enhance RF-to-DC conversion efficiency. A comprehensive theoretical analysis and performance evaluation of different microwave couplers are conducted to determine their impact on power distribution and impedance ...
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This paper presents an optimized microwave rectifier circuit that integrates various couplers to enhance RF-to-DC conversion efficiency. A comprehensive theoretical analysis and performance evaluation of different microwave couplers are conducted to determine their impact on power distribution and impedance matching. The study demonstrates that incorporating couplers into the rectifier circuit effectively reduces reflected power over a broad input power range. Among the evaluated configurations, the rectifier incorporating a branch-line coupler (BLC) exhibits superior RF-to-DC efficiency over a wide range of operating frequencies, input power levels, and output loads, ensuring broad impedance matching. To validate the proposed design, a rectifier circuit based on the BLC is implemented and fabricated at 2.45 GHz. The prototype consists of two identical sub-rectifying networks connected to the two output ports of the coupler, with the isolated port grounded. Experimental results indicate that the rectifier consistently achieves efficiency levels exceeding 50% for input power levels ranging from 0 to 12.5 dBm. Additionally, the design maintains high efficiency across a frequency range of 2.16 to 2.96 GHz. These findings underscore the potential of BLC-based rectifiers for high-efficiency microwave power transmission systems, offering enhanced energy harvesting capabilities and improved system performance.
Research Articles
Power systems
Hamed Shadfar; Hamid Reza Izadfar
Abstract
Calculating the current of the rotor bars in a squirrel cage induction motor (SCIM) using stator data is difficult, but it is very useful. With the calculation of the rotor bars’ current, analysis and investigation of some different parameters of the motor can be done, precisely. One of the faults ...
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Calculating the current of the rotor bars in a squirrel cage induction motor (SCIM) using stator data is difficult, but it is very useful. With the calculation of the rotor bars’ current, analysis and investigation of some different parameters of the motor can be done, precisely. One of the faults faced by SCIM is the broken rotor bar (BRB) fault. The breakage of one or more bars causes a change in the healthy bars' current and the motor's behavior and parameters. This paper introduces the method of calculating the rotor bars’ current in the SCIM in two healthy and defective states (breakage of 1 bar and 2 adjacent bars) using the multiple-coupled circuit (MCC) model. In addition to currents, some important parameters, such as speed, magnetic field, etc., will be calculated. For validation of results, a two-pole SCIM with a nominal specification of 1.1 kW, 220/380 V, and 50 Hz is subjected to experimental testing. The results are confirmed by practical tests and simulations using the Ansys Maxwell software.
Research Articles
Electronics
Khalil Monfaredi; Mousa Yousefi
Abstract
Objective: In this paper, a trans-conductance amplifier based on Common Mode Rejection Ratio (CMRR) enhancement block is presented. The proposed block is capable of eliminating common mode signals at input stage. This feature improves the gain and CMRR of the amplifier substantially. The Cascode structure ...
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Objective: In this paper, a trans-conductance amplifier based on Common Mode Rejection Ratio (CMRR) enhancement block is presented. The proposed block is capable of eliminating common mode signals at input stage. This feature improves the gain and CMRR of the amplifier substantially. The Cascode structure is also eliminated in proposed architecture, which resulted in favorably reduced power consumption due to low supply voltage requirements. Materials and Methods: The presented OTA is simulated in 180nm CMOS technology at Cadence Spectre environment with 1.5 v supply voltage proving it appropriate for low-voltage applications. The bias current of the proposed circuit is very low value of 3.9 μA. Results: Gain and phase margin for this block are achieved to be 83.96 dB and 61.68 degree, respectively. These results achieved while the circuit drive a 5pF load at its output. The power consumption of the proposed amplifier is interestingly very low value of 5.9 μW. Conclusion: It is interestingly concluded that the achieved specifications makes the block very much suitable for low-power applications.
