Characteristics Of Power Supply Research Articles

Micro water energy harvesting system based on tubular triboelectric nanogenerator

Abstract Constructing a micro-water energy-harvesting system for the power supply of micro-nano sensors in pipeline liquid transmission networks is of great significance. In this study, a micro water energy harvesting system based on a tubular triboelectric nanogenerator was designed, which achieves efficient energy harvesting and conversion by directly collecting the charge of the friction layer without the electrostatic induction effect. First, the working principle of the liquid-solid triboelectric nanogenerator is analyzed based on multi-physic coupling, and the potential distribution in the charge transfer process is analyzed. Second, the effects of liquid flow, pipe length, inner diameter, and material on the output characteristics of the triboelectric nanogenerator were investigated. Finally, the load power supply characteristics of the triboelectric nanogenerator were presented. The output characteristics of the liquid-solid triboelectric nanogenerator were proportional to the flow rate and inversely proportional to the inner diameter of the pipe. The output power of the liquid-solid triboelectric nanogenerator can be charged and stored by the capacitor through the rectifier bridge, and at least 30 LED lamp beads can be driven at a flow rate of 650 ml·min-1. This research has the potential to be applied to the construction of self-powered liquid-state monitoring intelligent sensors in pipeline networks.

Study on green power supply modes for heavy load in remote areas

In this study, the present situation and characteristics of power supply in remote areas are summarized. By studying the cases of power supply projects in remote areas, the experience is analyzed and described, and the applicability of related technologies, such as grid-forming storage and power load management, is studied, including grid-connection technologies, such as grid-forming converters and power load management. On this basis, three power-supply modes were proposed. The application scenarios and advantages of the three modes were compared and analyzed. Based on the local development situation, the temporal sequences of the three schemes are described, and a case study was conducted. The study of the heavy-load power supply mode in remote areas contributes to solving the problem of heavy-load green power consumption in remote areas and promoting the further development of renewable energy.

Design of a Portable Emergency DC Power Supply

Abstract In recent years, wireless or handheld devices have become increasingly widely used, especially in areas such as environmental monitoring and the Internet of Things. However, due to environmental conditions, they cannot rely on the power grid to provide electricity, and energy supply has become a key issue that restricts the deployment and operation of such devices. This article introduces the method and principle of applying a microcontroller control system to a portable emergency DC power supply, and proposes a method for a portable emergency DC power supply with adjustable and stable output. The output voltage can be adjusted in steps of 0.1-15V. This adjustable portable emergency DC power supply not only has the advantages of small volume and low loss of switch mode power supply, but also has the advantages of small output voltage ripple and good output characteristics of linear power supply. It has certain research significance and practical value.

Analysis of arc stability of plasma main arc and inter-wire arc in skew-coupling arc welding

By adjusting the inter-wire arc (IWA) posture, the skew-coupling arc (SCA) is proposed to address the polar effect in the cross arc, enabling decoupling control of heat, force, and mass transfer. Despite the advancement, the arc stabilization mechanism in the SCA remains poorly understood, hindering its application as a heat source in welding or additive manufacturing. To elucidate this mechanism, various influencing factors such as power supply characteristics, shielding gas composition, IWA posture, and plasma main arc (PMA) were analyzed. An electrical signal and high-speed camera synchronous acquisition system was utilized to analyze current-voltage waveforms and arc shapes. The results indicate that the arc stability of the SCA can be enhanced by ensuring specific external conditions. Constant voltage power supply enhances the self-regulating effect of the IWA, maintaining the IWA and the PMA in a hybrid state at all times. Introducing an oxidizing gas to the shielding gas can effectively suppress cathode spot climbing and stabilize the IWA. The vertical spacing between wires directly impacts the PMA deflection, while the wire horizontal angle has a lesser effect. The heat-regulating effect of the PMA column boosts the arc length regulation by the IWA. The current and the ion gas flow rate in the PMA minimally influence the SCA stability. These findings can provide a solid foundation for further applications of the SCA as heat source.

Design of dual-quadrant power supply based on bidirectional full-bridge transformation technology

Abstract Dual-quadrant programmable power supply is a bidirectional programmable DC power supply that integrates the functional characteristics of power supply and feedback load. This article adopts an automatic hybrid control method based on bidirectional energy flow, which adopts a phase-shifting control method and PWM control method respectively to achieve bidirectional control of power conversion.

Bacterial cellulose/multi-walled carbon nanotube composite films for moist-electric energy harvesting

Generation of renewable and clean electricity energy from ubiquitous moisture for the power supply of portable electronic devices has become one of the most promising energy collection methods. However, the modest electrical output and transient power supply characteristics of existing moist-electric generator (MEG) severely limit its commercial application, leading to an urgent demand of developing a MEG with high electrical output and continuous power generation capacity. In this work, it is demonstrated that a flexible bacterial cellulose (BC)/Multi-walled carbon nanotube (MWCNT) double-layer (BM-dl) film prepared by vacuum filtration can maintain the moisture concentration difference in the film MEG. Unlike previous studies on cellulose based MEG, BM-dl film has a heterogeneous structure, resulting in a maximum output power density of 0.163 μW/cm2, an extreme voltage of 0.84 V, and current of 2.21 μA at RH = 90 %. BM-dl MEG can generate a voltage of 0.55 V continuously for 45 h in a natural environment (RH = 63–77 %, T = 26–27 °C), which is in a leading level among existing reported cellulose-based MEGs. In summary, this study provides new ideas for innovative design of MEG, which is highly competitive in terms of energy supply for the Internet of Things and wearable devices.

A Power Self-Balanced High Step-Down Medium Voltage DC Converter With Expandable Soft-Switching Range

This paper proposed a power self-balanced high step-down medium voltage dc converter with expandable soft-switching range. The proposed one features the input voltage self-balance of each submodule and the current self-balance of each MOSFET, due to the sub-modules transmitting the same power through LC-coupled branches. The LC-coupled branch provides multiple direct AC power paths from medium voltage input to load, eliminating the losses caused by conventional multi-stage transmission. Each submodule of the proposed converter is a soft-switching unit that uses an auxiliary inductor to achieve soft switching, which reduces the resonant current and facilitates the expansion of the number of modules, without redesigning the transformer, instead of the conventional resonant converter that reduces the transformer magnetizing inductance to achieve soft-switching. Moreover, an auxiliary power supply scheme for the proposed converter is provided, which is used to solve the problem of difficult startup of the medium voltage DC converter, where the negative impedance characteristics of the series-connected auxiliary power supply are suppressed without the need for lossy voltage sharing resistors. A prototype with 1kV dc input and 100V/1kW output is built to verify the feasibility of the proposed topology.

Design optimization method of heating and cooling full cycle storage air conditioning in integrated energy system

Heating and cooling storage air conditioning is an important part of the integrated energy system, which can play an important role in the flexible conversion of thermoelectric coupling systems. Because storage air conditioning involves the dynamic characteristics of power supply on the source side and cold and heat demand on the load side, system capacity allocation is a problem of technical and economic optimization. This paper breaks through the traditional design method based on the hourly load distribution law of typical design days and proposes a performance-oriented design method for the bidirectional full-cycle dimension storage air conditioning system based on the system’s annual operation performance, which can take into account the hourly dynamic load distribution law of every day in the full heating season and the full cooling season coupled with the bidirectional demand of cold and heat loads. A more scientific and reasonable capacity configuration scheme for the storage air conditioning system is obtained. The design is presented with a concrete case.

Influence of the Electrical Characteristics of Pulsed Microwave Magnetron Power Supply on the Conditions for Plasma Formation in the Vacuum Chamber of Resonator-Type Plasmatron

The paper presents the research results of the influence of the electrical characteristics of a pulsed microwave magnetron power supply on the microwave discharge generation conditions, determined by the operating mode of the generating system as a whole. Plasma was formed in a vacuumized reaction-discharge volume located inside a rectangular resonator chamber. Depending on the operating modes of the microwave magnetron power supply, studies have been conducted for three modes of microwave discharge plasma generation: pulsed mode with a duty factor S ≈ 2; pulsed mode with a duty factor S ≈ 1.15; continuous mode. Probe measurements of the microwave power in the microwave discharge plasma volume and its local conductivity have been carried out. The paper presents the dependence of the power of microwave energy in the central area of the reaction-discharge quartz chamber of a microwave plasmotron on the amount of power consumed by the microwave magnetron, as well as the distribution of the electrical component of the microwave discharge plasma along the length and cross-sectional plane of the working volume. It has been established that for all studied modes of operation of the power source, with an increase in the power consumption of the microwave generator system, an increase in the microwave power recorded in the central region of the plasma discharge is characteristic. The continuous generation mode is characterized by a decrease in the uneven distribution of electromagnetic energy along the axis of the discharge chamber. It is shown that the transition from a pulsed to a continuous mode of microwave plasma discharge generation at the same level of power consumption by the generating system is characterized by a decrease in the value of the registered microwave power in the microwave discharge plasma volume and an increase in its local conductivity in particular areas of the reaction-discharge volume.

Life cycle climate performance evaluation (LCCP) of electric vehicle heat pumps using low-GWP refrigerants towards China's carbon neutrality

The environmental-friendly heat pump with low global warming potential (GWP), such as R1234yf, CO2, R290, and several potentially promising refrigerant mixtures, is increasingly essential for the electric vehicle (EV) to save energy consumption and extend the driving range. It is beneficial to achieve carbon neutrality by reducing both direct and indirect carbon emissions. Previously, the life cycle climate performance (LCCP) was a widely accepted metric to evaluate the carbon footprint of mobile air conditioning systems “from cradle to grave” for the internal combustion engine vehicle (ICEV), however, such LCCP analyses about EV heat pumps can hardly be found. To facilitate the EV industry and policymakers' better understanding of the environmental impacts of those low-GWP refrigerants, this study provided a comprehensive LCCP analysis for the EV heat pumps based on the system bench test results, local climates, local power supply characteristics, real-world driving patterns, vehicle cabin thermal sensation, and climate control load. Five low-GWP refrigerants, i.e., R1234yf, CO2, R290, binary blends of CO2 and R41 (with GWP values of 49), M2(R410A substitute with GWP values of 137), were compared against R134a and R410A in 31 provinces of mainland China. We also considered the impacts of electric vehicle adoption rates and the carbon intensity of electricity from 2020 to 2060. Results show that the total life-cycle emissions per vehicle are highly related to climate conditions in different provinces, while R290 shows the lowest emission on the national average. The national mean life-cycle emissions per vehicle are projected to decrease 14% by 2030 and 45.4% by 2060 under the current technological trajectory of electricity generation. By using low-GWP heat pump systems in EVs, the cumulative emissions counting all vehicles can be saved up to 1450 Mt. CO2e from 2020 to 2060.

FFC-NMR Power Supply with Hybrid Control of the Semiconductor Devices

The performance of FFC-NMR power supplies is evaluated not only considering the technique requirements but also comparing efficiencies and power consumption. Since the characteristics of FFC-NMR power supplies depend on the power circuit topology and on the control solutions, the control design is a core aspect for the development of new FFC systems. A new hybrid solution is described that allows controlling the power of semiconductors by switches (ON/OFF mode) or as a linear device. The approach avoids over-design of the power supply and makes it possible to implement new low power solutions constituting a novel design by joining a continuous match between the ON/OFF mode and the linear control of the power semiconductor devices.

Power Source Importance Assessment Based on Load Importance and New Energy Uncertainty

With the increasing penetration of new energy sources, the volatility and uncertainty of new energy output can lead to interruptions or fluctuations in the supply of electricity. Power cuts to critical loads can have a significant impact on public safety, social stability, and the economy. Dealing with the effects of uncertainty from new energy sources means we need to find and strengthen the important loads and power sources when designing and operating the power system. Therefore, the assessment of the importance of loads, conventional power sources, and new energy sources is crucial. This paper proposes a power source importance evaluation method based on load importance and new energy uncertainty. The method constructs a load importance evaluation system considering structural characteristics, outage loss, regulation capability, and other factors. To determine the importance of each load, the method uses the ideal solution method and ranks them accordingly. Next, the method calculates the power supply coefficient, which represents the power supply capability of the power source to the critical loads. This calculation involves using the three-point estimation method, which combines the characteristics of the new energy output and the importance of each load. Following that, the evaluation of load importance and the power supply capacity to critical loads is accomplished based on the ideal solution method, taking into account the diversity of power supply characteristics. This comprehensive evaluation allows us to assess the significance of each load and the power supply capability to meet the needs of critical loads, considering the unique characteristics of each power source. Finally, an example analysis is carried out on the IEEE39 to calculate the importance of various types of power sources, which can accurately reflect the power supply capacity of power sources to important loads and verify the validity of the evaluation method. This method provides subsidies for future power system grid planning and operation.

Study on discharge characteristics of pulsed power module under the condition of discharge short circuit fault

Efficiency and safety are key factors that must be emphasized in pulsed power applications. The discharge characteristics of pulsed power supply directly determine the performance of the railgun. This paper conducts a research on short-circuit faults in transmission coaxial cables of pulsed power supply. In order to study the effect of short-circuit fault on the discharge characteristics of pulsed power supply and system efficiency,a pulse-forming network with cable short-circuit failure and dynamic railgun model are established in the paper. The effect of short-circuit fault on peak current is discussed by simulation. The results show that the short-circuit fault currents are all higher than the currents under normal conditions, and the closer the short-circuit location is to the power supply side, the higher the peak value of current is. In some extreme case, the peak fault current exceeds 1.5 times the normal, which requires consideration of short-circuit fault protection measures, such as the addition of a DC circuit breakers.

A Wavelet Transform-Based Real-Time Filtering Algorithm for Fusion Magnet Power Signals and Its Implementation

With high real-time performance and a good filtering effect, the wavelet transform-based real-time filter is more commonly used in the fusion magnet power supply. Considering the signal characteristics of the fusion magnet power supply, the sliding time window method is widely used to satisfy the requirements of filtering efficiency. In this paper, an updated half-edge extension method is proposed to improve the boundary effect of sliding window data. Moreover, the hardware-based wavelet loopback structure is proposed to avoid the double computation of long sliding window data, thereby improving real-time performance and satisfying the demands of fusion magnet power supply filtering. The proposed half-edge extension method and the wavelet loopback structure are implemented by designed FPGA and experimented on the Experimental and Advanced Superconducting Tokamak (EAST) fusion magnet power supply system to verify the filtering efficiency. According to the experiment’s results, the proposed half-edge extension method has a better filtering effect, and the proposed wavelet loopback structure decreases the time by 67.4%, which can satisfy the requirements of the power supply system.

Study on Wireless Power Transfer System for EVs while Driving Using Continuous Repeater Power Transmission Coil

In recent years, the shift to electric vehicles (EVs) has become more prominent in many countries around the world. In line with this trend, research on systems that provide wireless power to running EVs is also underway in many countries. In order to realize this system, it is important to make the infrastructure easy and inexpensive, and one of the most important issues to be solved is to reduce the number of power sources used. We have proposed a repeater coil system as a power transmission method that can be expected to extend the power supply section per power source. In this paper, we discuss the usefulness of a series of repeater coils in a running wireless power transfer system, as well as their coil geometry and power supply characteristics.

Research progress on key factors of dielectric-barrier discharge plasma for wastewater treatment

Plasma treatment of wastewater is known as a new advanced oxidation process (AOP), which has attracted extensive attention. Dielectric barrier discharge plasma has the characteristics of no vacuum pumping and high electron number density. It has outstanding application value in various forms of plasma. There are many coupling factors that affect the characteristics of dielectric barrier discharge plasma and the effect of wastewater treatment. Optimizing the key parameters is of great significance to improve the treatment efficiency and reduce the treatment cost. This paper introduces the principle, experimental device, potential advantages and application value of dielectric barrier discharge, summarizes the influence rules of key factors such as high voltage power supply characteristics, electrode configuration, carrier gas and reactor design on the characteristics of organic pollutant wastewater treatment by dielectric barrier discharge plasma. The optimization and matching of multiple factors are important problems. This paper provides a useful reference for the engineering application of plasma technology for wastewater treatment.

Analysis of current protection in distribution networks with clean energy access

With the rapid development of the new energy industry, distributed generation (DG) is connected to the power grid on a large scale, and the traditional relay protection scheme is no longer suitable for modern power systems. In order to solve this problem, this paper establishes a mathematical model of the equivalent circuit of distributed photovoltaic power supply according to the external characteristics of photovoltaic cells, and analyzes its volt-ampmeter characteristics and voltage output characteristics of power supply. On this basis, it analyzes and puts forward the control mode of DG when the distribution network is faulty. On the basis of the study, this article has double feeder distribution network as an example, the analysis when the line fault occurring at different extents of DG connected to different position on the influence of the distribution network current protection, the results show that when answering DG side in the feeder bus for distribution network of current protection, pick a smaller effect on both ends of feeder, has a certain symmetry. Finally, the accuracy of theoretical analysis is verified by establishing a simulation model in PSCAD.

Разработка и верификация поведенческих моделей линейных стабилизаторов напряжения с защитой от короткого замыкания и перегрузки в рабочем цикле

The object of development are behavioral models of a linear negative voltage regulator in two modifications. Linear voltage regulators manufactured by KREMNIY EL GROUP JSC were chosen as prototypes for the models. IC 5348EM035 with a fixed output negative voltage value of 5 V, IC 5348EP035 with an adjustable output negative voltage value of 1.25V to 14.5V and their functional analogue IC UCC284DP manufactured by Texas Instruments were used. These are low voltage drop with duty cycle short circuit and overload protection regulators. Behavioral models are implemented in SPICE language through converting netlists of prototype equivalent circuits. Equivalent circuits on the regulators IC functional circuits were made, taking into account a typical switching circuit. Equivalent circuits of regulators are implemented on the standard mathematical blocks, limiters, dependent sources, controlled switches and passive elements. Parameter limits are written inside controlled sources by mathematical relations. When verifying behavioral models, it was established that the results of modeling the regulators operation correspond to the data in the technical descriptions of manufacturers. The verification was carried in typical switching circuits with given input electrical parameters. In present study the results of modeling the main characteristics of microcircuits are described: input and output voltages, voltage drop across the regulator and timing diagrams of the main modes of operation of the IC, including the mode of duty cycle short circuit and overload protection regulators. The developed and verified behavioral models of linear voltage regulators 5348EM035 and 5348EP035 and their functional analogue UCC284DP will be useful in the engineering, design and study of the characteristics of power supply devices for electronic and industrial equipment. These SPICE models are applicable in modern specialized CAD systems for circuit design and simulation.

Fast Distance Protection Scheme for Wind Farm Transmission Lines Considering R-L and Bergeron Models

The distributed capacitance of the line becomes larger as the scale of wind farms, the transmission voltage level, and the transmission distance increase. Hence, the error of the traditional time-domain distance protection scheme based on the R-L model, which ignores the distributed capacitance of the line, becomes unacceptable. Therefore, the error of the time-domain fault location method based on the R-L model, especially the maximum error range, is theoretically analyzed in this paper. On this basis, a novel fault location method based on the R-L and Bergeron models is proposed. Then, a fast time-domain distance protection scheme is designed. In the proposed scheme, the error in the fitting calculation is used to construct a weight matrix, and an algorithm for solving the time-domain differential equations is designed to improve the calculation speed and stability. Compared with the traditional frequency-domain distance protection scheme, the proposed scheme is independent of the power supply characteristics; thus, it is suitable for wind farm transmission lines. In addition, compared with the traditional method based on the R-L model, the proposed scheme effectively avoids the negative influence of the distributed capacitance of the line, which significantly improves the operating speed. Different types of faults are simulated by PSCAD/EMT-DC to verify the effectiveness and superiority of the proposed scheme.

ЭЛЕКТРОСНАБЖЕНИЕ НЕТЯГОВЫХ ЖЕЛЕЗНОДОРОЖНЫХ ПОТРЕБИТЕЛЕЙ

The features of power supply to consumers receiving energy from the energy system of railway transport are considered; as an object of non-traction consumption, a weight measuring complex is considered; it was determined that the existing methods of supplying electricity to remote facilities in the railway zone have significant shortcomings and the development of new technical solutions is required to eliminate them