Circuit Problems Research Articles

Mobile Interactive Multimedia to Assist Prospective Science Teachers Holding Conceptual Understanding in Problem-Solving Electrical Circuits

This research proposes a mobile interactive multimedia (MIM) system that allows students to interact with various simulations and animations of electrical phenomena and to apply their knowledge to solve problems in electrical circuits. MIM is a tool that enhances the students' conceptual understanding, correcting their misconceptions, and strengthening their problem-solving skills in electrical circuits, according to the students' knowledge type of transition in learning. The MIM was accessible through an Android-based device and was evaluated using a research and development (R&D) method. The Three Tier-Test and Multiple Misconception Revealing Test assessed students' conceptual comprehension and problem-solving ability. The study involved 53 prospective science teachers enrolled in the Electrical and Magnetism course in third-semester; 27 in the experimental group and 26 in the control group. The findings showed that the MIM met the validity, practicality, and effectiveness criteria. Therefore, the MIM was a valid, practical, and effective tool for enhancing the students’ conceptual understanding, correcting their misconceptions, and strengthening their problem-solving skills in electrical circuits, according to the students’ knowledge type of transition in learning.

Study of new commercial collectors for the recovery of coarse quartz particles in iron ore flotation

Currently, a small range of commercial collectors is available for the use in reverse iron ore flotation at Vale. This input represents a considerable unit cost, being essential for the concentration of low content itabiritic iron ores. The present work evaluated the reverse cationic flotation of an itabiritic ore with low iron content (39.6 % Fe) from the Iron Quadrangle (BR) in bench scale tests, focusing on the use of new collectors to remove coarse quartz. The sample presents 19% of its particles as oversize in the 0.150 mm sieve. The poor flotation of coarse quartz particles (>0.150 mm) causes significant problems in various iron ore flotation circuits by contaminating the concentrate. The study evaluated the performance of 10 new collectors from the etheramine family with different degrees of neutralization and at different collector dosages. The flotation process variables were set as industrially practiced at the Cauê iron ore plant (BR). In tests varying the specific collector dosage, the non-neutralized etheramines showed improved performance compared to the current 50% neutralized etheramine used in the plant, achieving industrial targets: concentrate SiO2 content rate lower than 4.5% (1.4%), tailings iron content lower than 23% (18.94%), metallurgical recovery greater than 66% (74,8%), and Gaudin Selectivity Index greater than 6.6 (10.5). The 0.150 mm oversize in the concentrate, mostly coarse quartz particles, was reduced from 5.7% down to 1.2%, indicating the potential for the industrial application of non-neutralized etheramines in the recovery of coarse quartz.

Improving the flow and thermal uniformities of transformer disc-type windings using a self-blocking oil circuit

The design of winding oil circuits is of great significance for improving the reliability, lifetime and loading capability of power transformers. Given the limited cooling capacity and local hot spot problems of the traditional oil circuits, a self-blocking oil circuit was introduced in this work. This study focused on exploring the potential advantages of this self-blocking oil circuit over the traditional ones in terms of the flow and thermal performance. To this end, the winding heat losses, flow and temperature were first calculated using a multi-physics coupling numerical model. Subsequently, the flow and heat transfer mechanisms of the winding were studied. Then, the flow and heat transfer performance of the winding with the self-blocking and traditional oil circuits were evaluated and compared. Furthermore, the effects of blocking degrees and oil flow rates on the winding flow and thermal performance were investigated. The results showed that compared with the traditional oil circuits, the self-blocking oil circuit exhibited a significant potential to improve the flow uniformity of transformer disc-type windings. It owned a larger cooling potential and the ability to lower winding hot spot temperature.

Integrating High-Sensitivity Photodetector and High-Energy Aqueous Battery in All-in-One Triple-Twisted Fiber.

Fiber-shaped photodetectors (FPDs) have attracted special attention to wearable health monitoring due to their 3D absorption capabilities. However, the practical application of traditional FPDs is severely limited by the irreversible degradation of performance caused by vulnerable interface compatibility on complex deformation and a single function. Here, an integrated photoelectrochemical FPD/battery device (FPDB) is designed, consisting of a common electrode, photoanode, anode, and sol-gel electrolyte as an isolation layer, which not only effectively avoids the short circuit problem of FPD but also endows high-efficiency energy storage capacity. As expected, the resulting all-in-one triple-twisted fiber-shaped FPDB simultaneously achieves high responsiveness of 151.45 mA W-1 and excellent volume capacity of 18.75 mAh cm-3. Such a stable architectural design and multifunctional integration of functional fibers accelerate the development of next-generation wearable fabrics.

Study of the Protection and Energy Transmission Modes of One Phase Short Circuit to Ground in Inverters.

Research indicates that phase-to-ground short-circuits in a frequency converter can subject the rectifier diode and IGBT to excessive voltage and current, potentially causing damage if the component selection margin during hardware design is insufficient. In order to solve the above problems, this paper studies the design of the LCL filter and ground short circuit problem of the hundred-kilowatt inverter. Firstly, an analytical method for calculating the DC bus capacitance and reactor of the inverter is proposed. The interaction between the DC bus capacitance and the reactor parameters and performance is considered in the implementation process. The parameters of the DC bus capacitor and reactor are given. Secondly, the one-to-ground short circuit of the inverter is studied, and the energy flow mode and mathematical expression of the double boost circuit, considering the influence of the leakage inductance of the power transformer, are given. Based on the above analysis, a method for determining the rectifier diode and IGBT, considering the one-to-ground short circuit of the inverter, is proposed. Finally, a one-hundred-kilowatt inverter is developed, and the corresponding experiments are carried out. The feasibility of the proposed scheme is verified by simulation and experiment.

Implementasi metode cramer menggunakan microsoft excel dalam penyelesaian rangkaian listrik arus searah

Direct current electrical circuits are one of the materials studied by students majoring in electrical engineering. To solve electrical circuit problems, students must understand the material on systems of linear equations and matrices. The purpose of this study is to find out what percentage of students apply the Cramer method with the help of Microsoft excel in solving problems of systems of linear equations in direct current electric circuits. This research is qualitative descriptive study. Data collection technique used is the documentation of test results. The subjects of this study were 52 students. First semester of the 2022/2023 academic year, majoring in electrical engineering. The instrument used is a description test of 5 questions, and the results of interviews. Data analysis technique by looking at the effectiveness of using Microsoft Excel in learning a system of linear equations with the Cramer rule method, the results are in the moderate category. To solve the problem of a system of linear equations in direct current circuits as much 62,2% of students it is easier to use the Cramer method and can quickly use Microsoft Excel assistance in calculations, even for many n variabels.

Design of CMOS circuits through transistor sizing techniques

With the increasingly diverse functional requirements of contemporary electronic products, the complexity of CMOS circuits often used in chips becomes higher and the number of transistors used increases. To solve the resulting performance problems of CMOS circuits, researchers have searched for many transistor sizing technologies. This paper summarizes three methods of CMOS circuit optimization. The paper introduces these three methods in terms of principle, effect, and application scenarios, and compares them respectively. Through analysis and simulation, it can be found that the use of these methods in circuit design can effectively achieve the purpose of improving speed, reducing power consumption, and improving the overall performance of the circuit. This lays a solid foundation for finally being able to present a good product with excellent performance and enhance the market competitiveness of the product. CMOS circuits are widely used, and circuit optimization is of great importance to the overall circuit design, and better optimization methods can even promote the development of the entire electronics and chip manufacturing fields.

Exploration and Application of Cloud-Network Integration Control Architecture in Industry

Cloud-network integration(CNI) is an inevitable choice to enhance the supply capacity of industrial Internet. In traditional industrial control systems, there are problems such as insufficient depth of perception, insufficient connectivity and insufficient analytical predictability. Firstly, an industrial CNI control architecture is proposed in this paper. Then a software-defined PLC integrated development & runtime environment based on the cloud framework is developed and deployed on a private cloud platform. An efficient 5G private network is created to facilitate wireless omnidirectional connectivity of cloud PLC. The problems of complex industrial field circuits and difficult to unify protocols are solved through 5G intelligent terminal devices. Finally, the cloud control architecture and software platform are successfully applied to the remote centralized control of the tundish preparation system in a steel enterprise’s two steelmaking plants. The results shows that the innovative system architecture meet the requirements for high-performance access, transmission, computing and storage in industrial plants, which achieves the cloud control of entire process industrial automation production.

Numerical approach to solve imprecisely defined systems using Inner Outer Direct Search optimization technique

In this paper, the Inner–Outer Direct Search (IODS) optimization technique is extended in the fuzzy environment to solve a fuzzy system of nonlinear equations. The proposed approach of fuzzy IODS converts the fuzzy system of nonlinear equations to an unconstrained fuzzy optimization problem. Then, the unconstrained fuzzy optimization problem is studied through the IODS technique. To validate the proposed algorithm, convergence analysis is performed. Further, three different fuzzy system of nonlinear equations are considered to demonstrate the algorithm. The fuzzy system of nonlinear equations is divided into various cases viz. fully fuzzy (when both the coefficient matrix and right-side vector are fuzzy) and only fuzzy (when either of the coefficient matrix or the right-side vector is fuzzy). For each individual case the numerical and graphical convergence of the obtained solutions were established. One electrical circuit problem is investigated to obtain the current in fuzzy environment and the same is compared with an existing method. It is observed that the closed form of the fuzzy solution contains the solution of the corresponding crisp system as well as the compared method. Finally, it can be noted that the proposed IODS approach can be applied to find the united fuzzy solutions for various science and engineering problems with easy implementation.

Developing A Textbook of Alternating Current Circuit Completed by Solving Problems Using Pythagoras Theorem

One of the most difficult chapters in physics is alternating current circuits. This material is also one of the materials tested in the university test. This is because the material requires a fairly complicated mathematical approach. Additionally, the alternating current circuit textbooks that have been used so far still use too high language. Therefore, the researchers need a simple way that can facilitate students in solving alternating current circuit problems and be packaged in a textbook. A simple way to solve alternating current problems can be done using the Pythagorean theorem. This is because the two are identical. Therefore, the purpose of this research is to develop a textbook on alternating current circuit material accompanied by a solution using a simpler method, namely the Pythagorean theorem. This study uses a research and development model with the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) stages. There were five research instruments used: (1) validation sheets; (2) teacher interview sheets; (3) teacher and student needs sheets; (4) test sheets; and (5) student response questionnaire sheets. The developed textbook has been validated by two experts and one user with a percentage value of 89.13%, so it is in the very valid category. In addition, based on the results of field tests on 34 class XII students of Senior High School in Jember, it is known that the developed textbook obtained an effectiveness percentage of 83.46% with an N-Gain value of 83.46. The textbook is in the high category and has a response questionnaire percentage of 80.3, so the developed textbook received a very positive response from students. By using this textbook, students can solve alternating current circuit problems more effectively and efficiently.

Alternating Layered Variational Quantum Circuits Can Be Classically Optimized Efficiently Using Classical Shadows

Variational quantum algorithms (VQAs) are the quantum analog of classical neural networks (NNs). A VQA consists of a parameterized quantum circuit (PQC) which is composed of multiple layers of ansatzes (simpler PQCs, which are an analogy of NN layers) that differ only in selections of parameters. Previous work has identified the alternating layered ansatz as potentially a new standard ansatz in near-term quantum computing. Indeed, shallow alternating layered VQAs are easy to implement and have been shown to be both trainable and expressive. In this work, we introduce a training algorithm with an exponential reduction in training cost of such VQAs. Moreover, our algorithm uses classical shadows of quantum input data, and can hence be run on a classical computer with rigorous performance guarantees. We demonstrate 2-3 orders of magnitude improvement in the training cost using our algorithm for the example problems of finding state preparation circuits and the quantum autoencoder.

Overview of Signal Processing Problems in Power Electronic Control Circuits

This paper examines various aspects related to digital signal processing in digital control circuits used in power electronics. The discussion focuses on several common issues, including the sampling rate of signals (including phenomena such as aliasing and synchronization), coherent sampling, jitter of sampling pulses, sequential versus simultaneous sampling in multichannel systems, signal resolution (including signal-to-noise ratio, noise-shaping circuits, and changes in sampling speed), interpolation and decimation, and the conversion of analog circuits into digital form. One of the key contributions of this paper is the introduction of a new formula for calculating the resultant signal-to-noise ratio for three-stage digital control circuits. By carefully considering and correcting for sources of error, it is possible to increase the signal-to-noise ratio and minimize distortion components. This, in turn, leads to improved output/input current and voltage parameters, which can have a positive impact on the overall quality of energy processing in power electronic circuits.

Transfer Function and Z-Transform of an Electrical System in MATLAB/Simulink

This paper presents the transfer function (T.F) and Z-Transform (Z.T) of an Circuits in MATLAB/Simulink. We have dealt with the electrical system, which consists of circuits in which there is a capacitor, resistance, and capacitance. Simulink is useful for obtaining the response of systems to input functions that are more complicated than step, impulse, ramp, or sine functions. The aims of this paper is to describe the solution of the equations of motion with One Degree and Two Degree Freedom of the equations of motion of the circuits by using transfer function equations in MATLAB/Simulink. We followed two applied mathematical methods to obtain the T.F and Z.F of a circuits in MATLAB/Simulink. Different graphics showed a close match result. Using these methods, researchers can effectively solve the RL and RLC circuit problems while presenting the results in excellent graphical form. The numerical approximation provides an acceptable result using the analytical one as a benchmark when we compare simulation results with analytical results.

Novel calibration algorithm of six-port receivers based on radial basis function network

ABSTRACT In this paper, the radial basis function neural network based on the orthogonal least squares (OLS-RBFNN) method is proposed for the first time for the calibration of the six-port receiver, which realises six-port accurate reception in the true sense. This algorithm overcomes the problems of an ageing circuit, narrow working frequency band and nonlinearity of the six-port receiver hardware. The RBFNN is a three-layer forward network, including an input layer, a hidden layer and an output layer. The transformation function of the hidden layer is the radial basis function. A six-port receiver test platform with an operating frequency band of 2.0–8.0 GHz is built to verify the performance of the six-port receiver based on OLS-RBFNN. The test signal is a 16-QAM signal with different bandwidths and different frequency bands. The test indicator uses error vector magnitude (EVM)， which represents the error between the received signal and the ideal signal sent. At last, the EVM of all tested data is less than 1.07%, and the best EVM is 0.57%. Therefore, the calibration accuracy of the OLS-RBFNN proposed in this paper is very high.

Crosstalk Analysis of Delay-Insensitive Code in High-Speed Package Interconnects.

The development of integrated circuits has increased the size of chip interconnects, which has brought challenges to interconnect design in chip packages. The closer the spacing between interconnects, the higher the space utilization, which can cause severe crosstalk problems in high-speed circuits. In this paper, we applied delay-insensitive coding to the design of high-speed package interconnects. We also analyzed the effect of delay-insensitive coding on crosstalk improvement in package interconnects at 26 GHz for its high crosstalk immunity. Compared to the synchronous transmission circuit, the 1-of-2 and 1-of-4 encoded circuits designed in this paper can reduce crosstalk peaks by 22.9% and 17.5% on average at a wiring spacing of 1-7 μm, which can achieve closer wiring spacing.

A Comparative Study of Two Common Pump-Controlled Hydraulic Circuits for Single-Rod Actuators

Pump-controlled hydraulic circuits are proven to be more efficient than conventional valve-controlled circuits. Pump-controlled hydraulic circuits for double rod cylinders are well developed and are in use in many practical applications. Existing pump-controlled circuits for single-rod actuators experience oscillation issues under specific operating conditions; that is identified as a critical operating zone on the load-velocity plane. The challenge in these circuits is to find out the proper way to compensate for the differential flow at both sides of the cylinder in all operating conditions. The two main types of valves commonly used by researchers, to compensate for differential flow in single-rod cylinder circuits, are: pilot-operated check valves, and shuttle valves. In this research, a performance comparison between circuits equipped with either valves, in terms of the size of the critical zone and the oscillations’ characteristics, was accomplished. Simulation studies showed that the circuits that utilize pilot-operated check valves possesses smaller oscillatory zones and less severe oscillations, when compared to circuits with shuttle valves. Experimental work verified the simulation results and proved the accuracy of the mathematical models. Hence, pump-controlled circuits with pilot-operated check valves are recommended to be the basic platform for further efforts to solve the oscillation problem in pump-controlled circuits.

RLC electric circuit model of fractional order: a Green's function approach

This article uses a hybrid approach that combines Green's function and a fixed point scheme to obtain a semi-analytical solution to the RLC electrical circuit's non-integer order differential equation. The fractional differential equation's order is determined by the two parameters α ∈ ( 1 , 2 ] and β ∈ ( 0 , 1 ] . The proposed method is unique because it can be extended to general nonlinear fractional systems. Another highly desirable feature of the proposed approach is that the construction of Green's function depends on both endpoints of the time domain, and hence the produced approximate solutions are highly accurate for fractional boundary value problems. We provide examples with figures and tables to demonstrate the effectiveness of our method in solving electrical circuit problems. TThe obtained approximate solutions are compared with exact solutions or numerical simulations to validate the applicability and accuracy of the proposed scheme.

Electromagnetic Vibration Characteristics of Inter-Turn Short Circuits in High Frequency Transformer

As a common fault of transformer winding, inter-turn short circuits cause severe consequences, such as excessive current and serious deformation of winding. Aiming to solve the problem of inter-turn short circuit at the end-winding and middle-winding of high frequency transformers (HFT), this paper considers the electromagnetic vibration characteristics of inter-turn short circuits (interleaved winding and continuous winding) at different positions, and the HFT is established by the multi-physical field coupling principle. Coupling equations for the inter-turn short circuit, as well as electromagnetic force and sound pressure level, are established to characterize the vibration noise mechanism of inter-turn short circuits. Furthermore, the HFT equivalent model is simulated in 3D finite element method (FEM) to emulate the real transformer operation and investigate the impact of interleaved winding and continuous winding under inter-turn short circuit faults. The short-circuit current and axial flux leakage, as well as the harmonic response of vibration acceleration and sound pressure level distribution, are obtained when inter-turn short circuits occur at different positions. Finally, the results show that the electromagnetic effect of the inter-turn short circuit in end-winding is worse than it is in middle-winding. Advantages in resisting impulse current make interleaved winding superior to continuous winding in terms of vibration and noise.

Fault detection and classification in DC microgrid clusters

With the rising popularity of DC microgrids, clusters of such grids are beginning to emerge as a practical and economical option. Short circuit problems in a DC microgrid clusters can cause overcurrent damage to power electronic devices. Protecting DC lines from large fault currents is essential. This paper presents a novel localized fault detection and classification technique for the protection of DC microgrid clusters. In this paper, a variational mode decomposition (VMD) and artificial neural network (ANN) based technique is proposed for accurate and effective fault detection and classification. This research aims to train an ANN that can detect and classify faults in DC microgrid clusters with multiple sources and loads by applying VMD to extract features of current signals. Different types of short circuit faults such as Pole to Pole and Pole to ground faults are considered under various grid operating conditions. The proposed method is capable of real-time fault detection and diagnosis, which can help prevent system failures and minimize downtime. The results indicate that the proposed approach is efficient and effective in detecting/classifying faults in DC microgrid clusters improving the reliability and system safety. The performance evaluation is carried out through rigorous case studies in MATLAB/Simulink environment to prove the efficacy of the proposed method. The VMD-ANN approach is shown to outperform other traditional signal processing techniques in terms of accuracy and robustness. Moreover, the proposed method is applicable to a wide range of DC microgrid clusters, making it a versatile and valuable tool for future research and development.

USE OF ORDINARY DIFFERENTIAL EQUATIONS APPLIED TO MECHANICAL AND ELECTRICAL PROBLEMS WITH FIRST ORDER LINEAR SYSTEMS

In recent years there has been an increased interest in the study of mathematics applied to engineering to study aspects of its teaching. In the present research work, a compilation of analytical concepts of differential equations applied to the solution of problems of electrical circuits, a branch of electrical engineering and mechanical engineering problems, specifical problems of spring-mass mechanical systems, through the description of the analytical solutions of direct current electrical circuits and spring-mass mechanical systems, applying differential equations. This method stands out among the diverse mathematical treatments used to solve this type of engineering problem, both for its demonstrative elegance and capacity to offer a total answer. Likewise, practical engineering examples related to the studied subject were presented and the results were obtained and analyzed by using the mathematical software, Wolfram Mathematica.