Current Distribution Method Research Articles

A flexible compensation device for single-phase-to-ground fault in distribution networks based on double-loop passivity-based control

Aiming at the problem that the existing single-phase-to-ground fault flexible compensation device has low compensation accuracy, long response time, and needs DC side power supply, a flexible compensation device based on double-loop passivity-based control is proposed. Firstly, the topology and working principle of the device are analyzed. And a compensation current distribution method of the bridge arm is proposed. Secondly, a double-loop passivity-based controller is designed. Finally, the proposed method is verified by MATLAB/Simulink software and 10 kV physical simulation system of distribution network. The comparisons between double-loop passivity-based control, passivity-based control, and proportional integration control is discussed. The result shows that the proposed method can accurately and rapidly compensate the fault current.

Advanced interdisciplinary techniques for revolutionized government ration dispensing system using IoT

The Indian Government is providing grains to those in need at affordable prices through a process known as the Public Distribution System. However, the current distribution methods employed in the public distribution system rely on manual processes, which may lead to errors, be time-consuming, and foster corruption. To address these issues, the proposed work employs Advanced Interdisciplinary Techniques such as RFID cards and readers to authenticate ration cardholders and ensure precise ration dispensing, significantly reducing inaccuracies and fraudulent activities. Furthermore, it incorporates a GSM-based mechanism with OTP authentication, adding an extra layer of security and efficiency. The GSM module sends a one-time password (OTP) to the user’s registered mobile number before dispensing rations, ensuring that only authorized individuals receive their entitled goods. Customers can select the goods they need from the allocation provided by the Government, and the amount will be automatically deducted from their RFID card based on the goods selected. A microcontroller manages the motor and relay to dispense items, while an alarm system alerts in cases of incorrect OTP entries, effectively deterring unauthorized access to rations. This system promises to make the ration distribution process more efficient, transparent, and accountable. Incorporating Advanced Interdisciplinary Techniques for Revolutionized Government Ration Dispensing System Using IoT.

Design and validation of frequency reconfigurable multiband antenna using varied current distribution method

Modern communication technologies require systems that can function at a wide range of frequencies, with diversity of radiation patterns, and with different types of polarization. In communication systems, the antenna serves as a filter; hence the ability to reconfigure the antenna is essential. The performance and design of a frequency band reconfigurable antenna are discussed in the paper, along with a comparison of the outputs of simulated and the fabricated design. Three PIN diodes are utilized to switch between various frequency bands. To increase selectivity, two ring resonators were added to the antenna's ground structure. As the current distribution changes in various switching instances, it is seen that the antenna operates at various resonant frequency bands. Connecting the diodes would change the current and field distribution in the chip design and thus change the resonant frequency. The antenna structure was designed and obtained results using High Frequency Simulation Structure (HFSS) software. The simulated and fabricated antenna is found to be operating in S band (2–4 GHz) and C (4–8 GHz) band of IEEE frequency bands with a gain in the range of 2.59 dB–9.54 dB. Typically the antenna resonates at various frequencies specifically, 2.38 GHz, 2.48 GHz, 3.98 GHz, 4 GHz, 4.45 GHz, 6.99 GHz, 7.2 GHz, 8.25 GHz. Under different switching cases of the diodes, the antenna is found to be radiating in different frequency ranges. By switching the PIN diodes under different cases, the current distribution path can be altered and as result of it, the antenna operates at variable frequencies.

Improved Flux-Weakening Method With Excitation Current Distribution for Hybridly Excited Asymmetric Stator Pole Doubly Salient Machine Based on Electrical Vehicle

The hybridly excited asymmetric stator pole doubly salient machine (HEASPDSM) has demonstrated great attraction to electrical vehicle (EV) for its strong robustness, while it suffers poor torque capability during the high-speed operation range. In order to solve such a problem, an improved flux-weakening method with excitation current distribution is proposed for the HEASPDSM in this article. First, the machine topology and the operating principle are briefly introduced. Second, the mathematical model is established, and the flux-weakening analysis is given out. Third, an excitation current distribution method has been put forward to the whole speed range along with the maximum torque per ampere (MTPA), the current and voltage limit (CVL), and the maximum torque per voltage (MTPV) from low to high operation automatically, which can widen the speed range and strengthen the torque capability. Finally, the feasibility of the proposed algorithm has been fully validated by both simulation and experimental results.

아파트의 전기서비스 요금 분배에 관한 시뮬레이션 연구

초록·키워드 목차 오류제보하기 Apartment complexes are the most common type of housing in Korean urban areas. In the single ("Danil") contract system, which is the most widely adopted electricity rate system in apartments in Korea, the total electricity charge for a whole apartment complex is calculated based on the average consumption per household by adding up the usage in common areas. Then, the total electricity charge is distributed to each household. From the current distribution method, this paper identifies abnormal distribution results through simulation studies. It is confirmed that the amount paid by each household is affected by the consumptions of other households. The results confirm that the current single (“Danil”) contract system violates the "Beneficiary pays principle", which is a primary principle for service fairness. #Electricity Bill #Single (“Danil”) Contract #Simulation #Scenario Analysis #Sensitivity Analysis AbstractⅠ. 서론Ⅱ. 문헌 연구Ⅲ. 시뮬레이션 연구Ⅳ. 결론참고문헌

Coupling Mechanism Analysis and Transient Stability Assessment for Multiparalleled Wind Farms During LVRT

In this paper, the coupling mechanism of phase-locked loop (PLL)-synchronized multiparalleled wind farms under grid faults is analyzed in detail. First, the coupling effects of the currents and the equivalent power angles (EPAs) among wind farms are identified by analyzing the voltage characteristics during low voltage ride-through (LVRT). Subsequently, a transient stability assessment method is proposed for multiparalleled wind farms to evaluate the effect of output currents of multiple wind farms on the EPA distribution characteristics. This method can be applied to evaluate whether each wind farm in the system has equilibrium points as well as evaluate the transient instability risk of the system during LVRT. In addition, the dominant wind farms for the system transient instability can be identified. Due to the coupling effects, any inappropriate current in the wind farm may deteriorate the EPA distribution characteristics and even cause loss of synchronism. Consequently, the current distribution method to minimize transient instability risk can ensure that each wind farm in the system has equilibrium points and effectively improve the multiparalleled wind farms stability during LVRT. Finally, the simulations results validate the effectiveness of the theoretical analysis and proposed method.

Are educational materials on medicinal products reaching out and useful to physicians? A survey of Singapore prescribers’ experiences and preferences

Background: Effective benefit–risk communication to healthcare professionals plays a vital role in promoting the rational use of medicinal products. The Health Sciences Authority (HSA) of Singapore has implemented Physician Educational Materials (PEMs) and Patient Medication Guides (PMGs) as educational materials to support informed decision-making. To evaluate their effectiveness as a safety communication tool, we sought to understand prescribers’ experiences and preferences with these materials. Methods: Invitations to an online survey were emailed to 387 healthcare professionals who had recently purchased the 22 medicinal products with requirements for educational materials in Singapore (“Purchasers”). The survey scope included their experiences with the receipt and usage of the materials, and their preferences towards the types of content and distribution channels for these materials. Results: The survey invitation reached 367 purchasers, of which 89 (24%) responded, including 66 who indicated that they had prescribed the surveyed products (“Prescribers”). Although only 47% of prescribers recalled receiving the educational materials, the majority who had used them found them useful in their clinical practice. However, the PMG was used less frequently than the PEM (59% vs 96%), and there was a mismatch between current and preferred distribution methods (mostly hard copies vs electronic copies). Conclusions: Prescribers who had received educational materials generally perceived them as being useful in raising awareness on treatment-associated safety concerns. The publication of educational materials on the HSA website and encouraging more routine distribution of PMGs by prescribers may improve their accessibility and facilitate safety communication on medicinal products to healthcare professionals and patients.

Evaluation Method of Voltage and Current Distributions on Asymmetrical and Equi-Length Differential-Paired Lines

Evaluation Method of Voltage and Current Distributions on Asymmetrical and Equi-Length Differential-Paired Lines

Design and Testing of a Low Voltage Solid-State Circuit Breaker for a DC Distribution System

In this study, a low voltage solid-state circuit breaker (SSCB) was implemented for a DC distribution system using commercially available components. The design process of the high-side static switch was enabled through a voltage bias. Detailed functional testing of the current sensor, high-side switch, thermal ratings, analog to digital conversion (ADC) techniques, and response times of the SSCB was evaluated. The designed SSCB was capable of low-end lighting protection applications and tested at 50 V. A 15 A continuous current rating was obtained, and the minimum response time of the SSCB was nearly 290 times faster than that of conventional AC protection methods. The SSCB was implemented to fill the gap where traditional AC protection schemes have failed. DC distribution systems are capable of extreme faults that can destroy sensitive power electronic equipment. However, continued research and development of the SSCB is helping to revolutionize the power industry and change the current power distribution methods to better utilize clean renewable energy systems.

TD-Root: A trustworthy decentralized DNS root management architecture based on permissioned blockchain

DNS root faces security vulnerabilities and trust risks due to centralized management architecture. Several related schemes have been proposed to alleviate the security vulnerabilities and trust risks. However, there are still some open issues, including tamper-proofing, security, deployability, etc. To address these issues, this paper presents a trustworthy decentralized DNS root management architecture called TD-Root based on permissioned blockchain. TD-Root is a tamper-proofing architecture and can tolerate one-third of malicious root servers behaving arbitrarily. Different from the current centralized distribution method, every root server maintains the consistent same root zone file through consensus algorithm, eliminating the security vulnerabilities and trust risks in current centralized management architecture. Correspondingly, we design a novel consensus algorithm, in which credence value and penalty mechanism are introduced to ensure the strong consistency, scalability, and security of TD-Root. Furthermore, a compatible deployment scheme which optimizes the lookup performance based on the blockchain data structure is proposed, reducing the deployment complexity and difficulty. Finally, TD-Root is implemented in Golang and validated through simulation using Google Cloud.

Adaptive current distribution method for parallel-connected PEMFC generation system considering performance consistency

The proton exchange membrane fuel cell (PEMFC) stacks are not widely utilized in the sector of the transportation industry, due to their limited efficiency and durability. In order to apply FC stacks in high-power occasions, the FC stacks are usually connected in parallel to form a multi-stack FC system (MFCS). During the operation, since the current from the stacks changes dynamically with different operating parameters, they usually present different performance. In the MFCS, if the performance of one stack is unsatisfactory, operating the underperforming stack without corresponding protection measures may further degrade its performance and thus break down the system. In order to slow down the performance degradation of the FC stacks and keep the consistency of stacks’ performance in MFCS, this paper has considered the effects of different stacks operating state and membrane area on the output current variations of stacks. And then an adaptive current distribution method realized by virtual droop technique considering the performance consistency of FC is proposed. Besides, this study builds a parallel-connected PEMFC generation system to verify the effectiveness of the proposed method. The validity of the proposed method has been demonstrated with experimental results. In addition, compared with the conventional control algorithm, the presented virtual droop control algorithm could get more satisfactory results. Such as improving the load voltage regulation and reducing the magnitude of the deviation between the actual output current and the reference current.

Current Distribution Method of Induction Motor for Electric Vehicle in Whole Speed Range Based on Gaussian Process

A current distribution method based on Gaussian process is proposed in this paper. This method can improve the accuracy of current distribution of induction motors for electric vehicles in whole speed range, and achieve high-performance output torque. First, a vector control system based on current distribution model is designed based on control requirement analysis of induction motor. Second, the mathematical model of output torque and current is established. And the current distribution law of the optimal electromagnetic torque under various operating conditions is qualitatively analyzed. Third, the experimental platform is built to obtain the discrete data of current distribution in whole speed range and the rotor time constants at different temperatures. Finally, the Gaussian process is introduced to establish the regression model based on current discrete data. The regression model distributes the current reasonably and accurately, which is embedded in the control system. Experimental results verify the effectiveness of the proposed method.

An Edge-Assisted Data Distribution Method for Vehicular Network Services

The current data distribution method of vehicular network cannot satisfy the strict spatiotemporal constraints on the transmission of massive service data. Neither can the 5th generation mobile network (5G) meet the massive data demand of vehicular network services. To solve the problems, this paper designs an edge-assisted service data distribution method for vehicular network services. Specifically, the service data distribution was predicted by time series analysis through edge computing, based on the storage capacity of base stations. Then, a spatiotemporal constrained data sharing algorithm was proposed, which sets up a distribution tree to evaluate the importance of each vehicle in data transmission, and heuristically chooses the most important vehicles as seeds to speed up the vehicle-to-vehicle data sharing. Finally, the simulation experiment verifies that our method can greatly reduce the load of 5G network without breaking the spatiotemporal constraints of data transmission in vehicular network.

Optimal Design of High Efficiency Distributed LDC Power Supply

Unlike the conventional battery-integrated LDC system, the distributed battery system can reduce the component cost by downsizing the LDC power supply, and balancing charge control method can improve battery utilization rate and lifetime, distributed LDC power supply development is progressing actively. n this paper, configuration of LDC power supply system is forward converter that can minimize the number of switch components and power supply size, it is applied to reduce loss caused by reset, which is a disadvantage of forward converter. It explains design of LDC power supply considering transformer temperature change according to switching frequency. A problem occurring in distributed control proposed a method to solve using Active Current Sharing method. the design of proposed high-efficiency forward converter and current distribution method were verified through experiment.

Optimal Design Method of MIMO Antenna Directivities and Corresponding Current Distributions by Using Spherical Mode Expansion

This paper proposes a new methodology to design optimal antennas for MIMO (Multi-Input Multi-Output) communication systems by using spherical mode expansion. Given spatial channel properties of a MIMO channel, such as the angular profile at both sides, the optimal MIMO antennas should provide the largest channel capacity with a constraint of the limited implementation space (volume). In designing a conventional MIMO antenna, first the antenna structure (current distribution) is determined, second antenna directivity is calculated based on the current distribution, and thirdly MIMO channel capacity is calculated by using given angular profiles and obtained antenna directivity. This process is repeated by adjusting the antenna structure until the performance satisfies a predefined threshold. To the contrary, this paper solves the optimization problem analytically and finally gives near optimal antenna structure (current distribution) without any greedy search. In the proposed process, first the optimal directivity of MIMO antennas is derived by applying spherical mode expansion to the angular profiles, and second a far-near field conversion is applied on the derived optimal directivity to achieve near optimal current distributions on a limited surface. The effectiveness of the proposed design methodology is validated via numerical calculation of MIMO channel capacity as in the conventional design method while giving near optimal current distribution with constraint of an antenna structure derived from proposed methodology.

A Hybrid Electrical Magnetic Power Quality Compensation System With Minimum Active Compensation Capacity for V/V Cophase Railway Power Supply System

To solve the power quality problem in a V/V cophase railway power supply system, a hybrid electrical magnetic power quality compensator (HEMPQC) based on magnetic static var compensator (MSVC) and hybrid power quality compensator (HPQC) is proposed in this paper. Compared with conventional HPQC, the proposed HEMPQC could keep the active compensation capacity minimum to any load condition. The output current of MSVC is conducted to make the active compensation capacity minimum. The coupling branch impedance optimum design procedures are deduced. Based on the instantaneous current detecting and reactive current distribution method, the collaboration control strategy is proposed for HEMPQC to achieve the dynamic tracking of the reference signals. Finally, simulation and experimental results have verified the proposed hybrid compensation system and compensation method effectively.

Current Distribution Model and Control Principle of MgAlON Composites by Spark Plasma Sintering (SPS)

The current distribution had remarkable effect on the microstructure and properties of MgAlON composites in the process of spark plasma sintering (SPS). MgAlON composites, using alumina, magnesia and aluminum as starting materials, were prepared by SPS. Based on the current distribution method, the current distribution model on samples and single grain was established, and the basic electric current control principle was analyzed. It was found that the current conveyance by sample or single Al grain could be expressed by a formula including B and I.In the formula, B was the Al volume fraction and I was the total current. When the Al volume fraction was controlled within 12%, the current conveyance by sample increased significantly with the Al addition increasing. Meanwhile, the current conveyance by single Al grain decreased significantly. The sintering speed and properties of MgAlON composites by SPS would show a significantly change.

An Optimal Current Distribution Method of Dual-Rotor BLDC Machines

This paper proposes an optimal current distribution method of dual-rotor brushless DC machines (DR-BLDCMs) which have inner and outer surface-mounted permanent-magnet rotors. The DR-BLDCM has high power density and high torque density compare to the conventional single rotor BLDCM. To drive the DR-BLDCM, dual 3-phase PWM inverters are required to excite the currents of a dual stator of the DR-BLDCM and an optimal current distribution algorithm is also needed to enhance the system efficiency. In this paper, the copper loss and the switching loss of a DR-BLDCM drive system are analyzed according to the motor parameters and the switching frequency. Moreover, the optimal current distribution method is proposed to minimize the total electrical loss. The validity of the proposed method was verified through several experiments.

Improving Sharia Risk Compliance: Proposing Daily Index for Mudharaba Contract in Islamic Banks in Indonesia

Objective – The objective of this paper is to analyze the profit distribution method applied in Islamic banks in Indonesia and to propose better method in order to improve sharia risk compliance. Methods – Employing a descriptive quantitative method and literature review . This paper evaluate weaknesses of the current profit distribution method and proposes daily revenue index to solve the problems arising from using current method which is unfairness between bank and customers. Results – By the two current profit distribution methods which use monthly revenue index calculated only at the end of the month, there are potential injustices occur. Therefore, instead of using monthly index, daily index is proposed. There are two steps in calculating profit distribution by using daily revenue index: (1) Accumulating Source of Fund (SoF), Reserve Requirement (RR), and Source of Fund after Reserve Requirement (SoFaRR), and (2) Determining Average Financing (AF), Revenue Index (RI), Cost Index (CI), Revenue Sharing Index (RSI), and Profit Sharing Index (PSI). Conclusion - Daily revenue index will solve the unfairness problems arise from current profit distribution method applied in Islamic banks. Daily revenue index is also applicable if Islamic banks apply profit and loss sharing instead of revenue sharing.

Design of a quasi-optical mode converter for 94 GHz gyrotron

Based on geometry optics theory and vector diffraction theory, mode converter is studied to convert the gyrotron and other high-power microwave oscillator output mode into quasi-optical Gaussian beam, using Vlasov launcher and two quasi-optical reflector achieved quasi-Gaussian mode TEM00 transverse output.The working mechanism of Vlasov launcher in analyzed, the radiation field is calculated by using vector diffraction theory, and the surface radiation field is also calculated by using the surface current distribution method. A built-in quasi-optical mode converter is designed to convert the 94GHz, TE62 model millimeter wave into quasi-optical Gaussian beam through programming.