Efficient Power Supply Research Articles

РЕКОНФИГУРАЦИЯ СУЩЕСТВУЮЩЕЙ ЭЛЕКТРИЧЕСКОЙ СЕТИ НАСЕЛЕННЫХ ПУНКТОВ НА ОСНОВЕ ДАННЫХ О ЗАГРУЗКЕ ПОТРЕБИТЕЛЕЙ

The problem of reliable and efficient power supply to municipal consumers can be solved by modeling and prognostic planning of consumption centers development. Analysis of statistical and forward-looking information allows planning of intra-city power supply network, identifying of emerging consumer clusters, and pursue an energy-saving policy in relation to distribution networks.

Power Balance Management of an Autonomous Hybrid Energy System Based on the Dual-Energy Storage

The urgent task of modern energy is to ensure reliable and efficient power supply to consumers, even those located in remote, far end places. A hybrid energy system with renewable energy sources is a promising way to ensure such a process. A characteristic feature of the modes of such systems, especially with high penetration levels of renewable energy sources, is the presence of ripples in the charge–discharge currents of the batteries used as energy storage devices. Batteries operation with such current fluctuations leads to rapid degradation of its characteristics as well as a reduction in its lifetime. Furthermore, it leads to a decrease in the reliability of the power supply system and an increase in the cost of generated electricity. A significant drawback of hybrid systems built according to well-known standard schemes is the inefficient use of the primary renewable energy, which is especially critical for energy systems located geographically in areas with severe climatic conditions. This article proposes a new construction method and an algorithm for controlling the modes of hybrid energy systems based on a dual-circuit energy storage device, which increases their reliability and energy efficiency. The prominent outcomes of operating modes of a hybrid power plant with a high penetration of renewable sources are presented, which proves that the proposed method of construction and the proposed control algorithm provide reliable and efficient control of the power balance of the hybrid power system in all possible operating conditions. In addition, the overall efficiency of the proposed renewable energy system is increased from 28% to 60% compared to standard hybrid power plants.

The Application of High Efficiency and Low Noise Switching Power Supply in Fiber Optic Gyroscope

For high-precision fiber optic gyro systems, the efficiency and noise in the switching power source limits its application and also affects the system's light source and signal processing circuit, resulting in output errors. The interference mechanism of switching power supply ripple noise on super luminescent diode (SLD) light source and demodulation module in fiber optic gyro system is analyzed. A high-efficiency and low-noise switching power supply based on synchronous rectification is proposed. The power supply uses RC circuit to realize adjustable switching frequency. The push-pull isolation topology, LC filter and LDO regulator circuit are used to achieve constant voltage output with peak-to-peak ripple noise of less than 1mV. The conversion efficiency of the switching power supply is improved by 10%, which provides a high-quality power source for the high-precision fiber optic gyroscope. In the meanwhile, the switching power source for FOG is 541cm in size, which is beneficial to the miniaturization of inertial navigation system.

Current Control Strategies for Parallel-Form Switch-Linear Hybrid Envelope Tracking Power Supply With Two Switched-Mode Converters to Achieve Optimal Power Allocation

Switch-linear hybrid (SLH) envelope tracking (ET) power supply is one of the mainstream structures for achieving both high efficiency and high bandwidth. When tracking a high bandwidth envelope signal, the overall efficiency of SLH ET power supply with the single switched-mode converter is limited. This paper adopts two switched-mode converters with different tracking bandwidths instead of the single switched-mode converter. The switched-mode converter with low tracking bandwidth is called slow switched-mode converter (SSMC), which aims for providing the low-frequency load current components with low slew rate; while the switched-mode converter with high tracking bandwidth is called fast switched-mode converter (FSMC), which copes with the high-frequency load current components with high slew rate. The rest load current components are processed by the linear amplifier. The class-A linear amplifier is employed for reducing the complexity of the circuits, which works as a voltage regulator that does not sink the load current. The SSMC provides the majority of the load current with low switching frequency. Thus, the switching loss of the SSMC is not high. The FSMC is operated at high switching frequency but provides the minority of the load current, and thus the switching loss of the FSMC is not high. The valley-point current control and peak current control with critical continuous current mode are proposed for the SSMC and FSMC, respectively, achieving the desired power allocation among the SSMC, FSMC, and the linear amplifier. Finally, a prototype is fabricated in the lab aiming for tracking a 10-MHz envelope signal and 20-W average output power. Experimental results are provided to verify the effectiveness of the proposed configuration and its current control strategies. The efficiency of the proposed SLH power supply is 77.0%, a 4.5% efficiency improvement compared with the SLH ET power supply with the single switched-mode converter.

Research on Integration Model of Shore-to-ship Power Supply System with High Proportion Renewable Energy

The traditional shore to ship power supply system has been unable to meet the demand of high efficiency and high power quality for warships. Combining with renewable energy and energy storage, this paper studies the integration mode of high proportion renewable energy shore-to-ship power supply system, and proposes three system topologies. According to the demand of 50Hz load power supply, the system topology of DVR scheme is more conducive to improving power supply efficiency, and has grid-connected/islanded function. It not only greatly reduces the dependence on Municipal electricity, improves the reliability and automation, but also realizes the demand of energy saving and environmental protection. Combined with DVR scheme, the control strategy based on inductance current band-pass feedback is proposed to further ensure the high power quality of the load.

Increasing power supply efficiency of livestock complexes at small farms using renewable energy sources

The paper provides technical recommendations for designing power supply systems for livestock complexes of small farms based on renewable sources of electric energy. Resource analysis of solar and wind energy on the Russian Federation territory shows that the use of the hybrid solar-wind power plants is most appropriate. In the case, it is advisable to use batteries and diesel generators to ensure reliable and uninterrupted power supply. Herein is offered a version of making up a structural diagram of power supply system for a small farm with combined power supply from centralized power grids and renewable energy sources. It is shown that the use of such a system can significantly save due to the power not consumed from the grid, and also allows selling excess energy to the power system. Herein is offered a version of building up a structural diagram of an autonomous power supply system based on a hybrid solar-wind power plant and a diesel generator for those regions, where there is no distributive electrical network. A design of a vortex wind power installation has been developed for practical use as part of the considered options for power supply schemes, which allows using small winds and low-potential thermal upward flows, reducing low-frequency vibration and noise, placing it on the top of industrial buildings with ease of installation, maintenance and repair.

Effective electrical equipment operation process management based on automated information decision making support

The article studies the issues of ensuring electrical equipment operability during operation process, as an indicator of reliable and efficient power supply of heterogeneous consumers. The problem of electrical equipment operation process managing is considered from the point of view of many technical and economic factors that affecting decision making and the priority of taking measures to emergency prevention. The concept of information decision-making support, aimed at controlling the electrical equipment actual condition and planning work to ensure its operability in the short and long term, was proposed. An example of the information decision-making support implementation when choosing objects with the maximum risk of operability loss was given.

Research on Harmonic Suppression of High Temperature Boiler Based on Three-phase PWM Rectifier

Traditional boiler temperature control is based on thyristor voltage regulation, and the output AC voltage is controlled by controlling the trigger angle α of thyristor, so that the boiler temperature can be controlled in the pre-set range. However, this way of voltage regulation and temperature control will cause serious harmonic pollution to the power grid, and the output current has high harmonic content and low power factor. At the same time, the traditional three-phase load connection mode generally adopts star connection, and the load is pure resistive silicon carbide. Because of long-term use, the aging of silicon carbide heating rod is different, in fact, it is asymmetric load, three-phase load. The unbalance will cause three-phase unbalance, which will make the voltage of a certain phase exceed the rated working voltage of the heating rod, and greatly reduce the service life of the heating rod. Therefore, in order to improve the efficiency of power supply, reduce harmonic pollution and solve the problem of three-phase unbalance, this paper proposes a three-phase PWM rectifier circuit, which converts AC to DC, and realizes DC voltage regulation and temperature control through PI regulator. In this paper, the feasibility of the scheme is verified by simulation and comparative analysis.

Improving the accuracy of calculations of electrical loads for industrial enterprises

Nowadays many enterprises of the mineral resource complex install modern and energy-efficient equipment. By the way nobody takes into account that it influences the correctness of the electrical loads calculation. The aim of this study is to determine the necessity of adjustment of the electrical loads of the calculation method in order to avoid an unjustified overestimation of power consumption, which affects the reliability of the whole system. Conducted analysis of the difference between reference and actual values of electrical loads calculation shows a discrepancy of more than 25%. This suggests that reliable determination of power consumption at the initial design stages allows one to create an efficient power supply system.

Organic Photovoltaics: Toward Self-Powered Wearable Electronics

In the past several years, research in soft and flexible electronics has promised to yield developments in wearable technology, including health and fitness monitoring tools, independence and mobility aids for the disabled, and human–computer interfaces for virtual and augmented reality. However, as these devices become thinner and lighter, they demand efficient power supplies with similar mechanical properties. Organic photovoltaics (OPVs)—–known for their high flexibility, lightweight, and scalable fabrication methods—have recently attained power conversion efficiencies of over 17% and are excellent candidates to power these next-generation wearable devices. In this paper, we discuss recent developments in flexible OPVs, including advances in materials, structure, and integration with additional wearable components, such as sensors and displays. In addition, we describe our recent work in developing a self-powered actuator for a tactile feedback system.

Energy Scheduling for Networked Microgrids With Co-Generation and Energy Storage

This paper proposes an online algorithm for energy storage management in networked microgrids (MGs) with co-generation based on the concept of quality-of-service in electricity (QoSE). The concept of networked MG with distributed renewable energy supply and co-generation makes power supply smarter for electricity/heat using, which has advantages of increasing power supply efficiency and reliability by coordinately scheduling the power supply in a networked way. The demands include quality usage of electricity load and heat. The networked MG central controller aims to minimize the operation cost and guarantee the outage probability of quality usage, i.e., QoSE, by scheduling electricity among renewable energy sources, energy storage systems, co-generation, and external utility market. We formulate the problem as a stochastic programming problem with QoSE and battery capacity constraints. By introducing the QoSE virtual queues and energy storage virtual queues, we transform the original problem into a problem that is applicable to employ the Lyapunov optimization technique. The proposed algorithm is an online algorithm with low complexity for practical implementation, and also provides several deterministic performance bounds. We perform extensive simulations to demonstrate the effectiveness of the proposed algorithm, which exhibits significant efficiency on operation cost reduction compared with an alternative benchmark solution.

Possibility of Utilizing Wind Turbine to Recover a Portion of the Kinetic Energy Losses of a Car

In this paper, the possibility of utilizing a wind turbine to recapture a portion of the kinetic energy losses of a car, irrespective of being a traditional car that is propelled by an internal combustion engine or an electric vehicle (EV) that is propelled by an electric motor, is appraised. To investigate the topic, a small wind turbine has been inserted at the back of the condenser of a car to recover a portion of the kinetic energy of wind passing through the condenser's crisscrossed bars. A portion of this wind is caused by wind existing outside the car, and the main portion is caused by the kinetic energy originating from the car movement. In the absence of the wind turbine, the wind passing through the condenser's crisscrossed bars hits the middle part of the car's chassis and loses its energy. Thus, not only the wind turbine uses a portion of the kinetic energy losses of the car to produce electricity but also, since it has been embedded at the back of the condenser, it has no impact on the aerodynamic coefficient of the car, i.e., it does not produce any extra resistive force. When the car is parked, and there is no kinetic energy resulting from the car movement, a small flow of wind available outside the car is converted into electricity stored in the car's battery. To realize the proposed scheme, a 100-W wind turbine, a permanent-magnet synchronous generator coupled to the turbine, and a novel built hybrid power generation system combining the wind-driven generator's output power with that of the car's battery have been embedded in an EV having a total weight of 1855 kg. Experimental measurements conducted under realistic operation of the EV are given that prove the traveling range of the EV and the power efficiency of the EV's power supply are enhanced by, 6.4 km and 0.2% respectively, by recovering only a portion of the kinetic energy losses of the EV. These two benefits also prove the novelty and contributions of this work in successfully recovering a portion of the kinetic energy losses of a car by using a small wind turbine embedded in the car.

Adaptive Voltage Position Control for Pulse Power Supply in Electrical Discharge Machining

In order to improve the power efficiency and dynamic response of the pulse power supply in electrical discharge machining (EDM), an adaptive voltage position control with a flexible ability of the discharge energy adjustment, dedicating to the pulse power supply in EDM, is proposed in this paper. By introducing the sum of the gap voltage and current as a control object, the voltage mode and the current mode control can be switched freely, which fits the discharge gap characteristics. Based on the analysis of the dynamic response and the steady state of the converter, the design of key power components and control parameters are given. As a result, a fast switch between the voltage control and current control, a high dynamic response on the gap state changing, and a well-discharge current as well as a discharge energy control in a discharge period can be achieved, which means a high power efficiency, a high machining consistency, and a high machining speed for the pulse power supply.

Using Flexible Blades to Improve the Performance of Novel Small-Scale Counter-Rotating Self-Adaptable Wave Energy Converter for Unmanned Marine Equipment

Unmanned marine equipment has been increasingly developed for open seas. The lack of efficient and reliable power supply is currently one of the bottlenecks restricting the practical application of these devices. In order to provide a viable power supply method for unmanned marine equipment, such as sonic buoys and sea robots, we originally propose a novel small-scale flexible blade wave energy converter (WEC) based on self-adaptable counter-rotating operation mechanism. The flexible blade WEC is designed on the basis of the rigid blade WEC with the caging device. This paper identifies the key factors affecting WEC performance through theoretical analysis. According to the numerical simulation analysis, the output mechanical power of the double-layer absorber is 12.8 W, and the hydraulic efficiency is 36.3%. The results of the verification experiment show that the peak power of WEC is 5.8 W and the average power is 3.2 W. The WEC with 65Mn flexible blade under most experimental conditions has the best performance when the blade thickness is 0.10 mm. The study shows that the new generation WEC can effectively overcome the excessive fluctuation of the output power of the previous generation WEC. The output power curve of the novel WEC is relatively smooth, which is conducive to its smooth operation and subsequent utilization and storage of electrical energy.

A genetic algorithm based dynamic pricing for improving bi-directional interactions with reduced power imbalance

Active supply-demand interactions in a smart grid are essential for reducing grid power imbalance which is important for the security and efficiency of power supply. A key element to the success of such interactions is the proper pricing strategy. The latest game-theory based dynamic pricing methods require information exchanges not only between the supply and demand sides, but also among individual buildings, since they make decisions for one building's demand response based on/influenced by operations of the others. However, in practical applications in which a number of buildings are considered, the latter information exchanges are extremely difficult due to the concerns of privacy, communication complexity and high computation load. Therefore, this study proposed a genetic algorithm based dynamic pricing method for improving bi-directional interactions with reduced power imbalance, which does not require information exchanges among individual buildings. In this study, at the demand side, targeting at minimizing daily electricity cost, a non-linear programming based demand response control is performed in individual buildings at a dynamic price given by the grid operator genetic algorithm optimizer. Targeting at reducing grid power imbalance, the genetic algorithm optimizer is used by the grid operator to search for a better dynamic price based on the aggregated demand response results. Such interaction will continue until the grid power imbalance cannot be further reduced. The impacts of demand elasticity are also investigated on performance improvements. The proposed pricing method can be used in practical applications to improve dynamic pricing of a smart grid for reduced grid power imbalance and thus increased operation efficiency.

Autonomous power generation facilities, hybrid structures comprising renewable energy sources

Introduction: the implementation of land development programmes in the polar regions, Siberia andFar East turns more complex due to power shortages in these areas. High electric energy rates and the need to maintain special purpose buildings encourage engineers to develop autonomous energy supply systems.Methods: the co-authors have analyzed several types of autonomous power supply facilities and series of autonomous power supply units designated for the power supply to the production machinery installed as part of various economic and special-purpose facilities, located at a long distance from industrial sources of electric energy.Findings and discussion: the co-authors present an algorithm for the selection of the configuration of an autonomous power supply system. The co-authors employ the findings of their analysis to substantiate the choice of a solar power station as a supplementary source of energy used as part of hybrid power generation systems.Conclusion: the algorithm developed by the co-authors may be used to design an efficient autonomous power supply system comprising hybrid units.

Performance characteristics of a Novel point Absorber-type WEC based on counter-rotating self-adaptable movement mechanism

ABSTRACT Marine equipment generally lacks efficient power supply methods. The high energy density of wave energy can facilitate the converter miniaturization and make them easily integrated into marine equipment. This paper presents a novel point energy absorber-type wave energy converter, which is based on the counter-rotating self-adaptable movement mechanism. Comprehensive theoretical analysis, numerical optimization and verification experiments were conducted on its performance characteristics. It was found that the hydrodynamic performances of the WEC are greatly affected by the rotational speed and diameter, and the interaction between the double absorbers is exacerbated by the stabilizing fins.

A New Standby Structure Integrated With Boost PFC Converter for Server Power Supply

In the standby stage of a server power supply, the flyback converter has been widely used due to its simple structure and low cost. However, since the flyback converter suffers from high-voltage stress and a large transformer, it degrades the efficiency and power density of the server power supply. To relieve these drawbacks, this paper proposes a new standby structure where a flyback converter is integrated with a boost power-factor-correction (PFC) converter. The proposed standby structure can relieve the high-voltage stress and eliminate the large transformer of the conventional flyback converter because the primary side of the flyback converter is merged with the boost PFC converter. Thus, the proposed structure can achieve high efficiency and high power density in the standby stage. Furthermore, it can help the boost PFC converter achieve a soft switching operation, which results in a high-efficiency PFC stage. As a result, the proposed structure improves the overall efficiency and power density of the server power supply. The validity of the proposed structure is confirmed by a prototype with 100–240 Vrms ac input, 750-W PFC output, and 12-V/2-A standby output.

Evaluation of Ice Adhesion Strength on the Oxidation of Transmission Line ACSR Cable

Ice accumulation on Aluminum Conductor Steel Reinforced(ACSR) cable during winter is an important matter in terms of safety, economy, and efficient power supply. In this work, the ice adhesion strengths of ACSR cable oxidized during different periods(7 years oxidized and 15 years oxidized) are evaluated. At first, a plate type dry oxidation standard specimen, whose surface characteristics are similar to those of ACSR cable, is prepared. Dry oxidation standard specimens are heat-treated at 500 °C for 20, 60, and 120 minutes in order to obtain different degrees of oxidation. After the dry oxidation, surface properties are analyzed using contact angle analyzer, atomic force microscopy, spectrophotometer, and gloss meter. The ice adhesion strengths are measured using an ice pull-off tester. Correlations between the surface properties and the ice adhesion strength are obtained through a regression analysis indicating a Boltzmann equation. It is revealed that the ice adhesion strength of 15- year oxidized ACSR cable is approximately 8 times higher than that of ACSR-bare.

Analysis and Test Efficiency of a High-Power Pulsed Power Supply Based on HIA

The high-power pulsed power supply based on homoploar inductor alternator (HIA) was successfully used as a primary power supply of the pulse load. This type of power supply has the advantages of high-power density and high reliability. The efficiency of this power supply is an important parameter in the design of this power supply. This paper presents the analysis and test efficiency of it. The theoretical calculation is consistent with the test, and the results show that the efficiency is 75%–80%; the armature copper losses account for the largest proportion of total losses, and the iron losses take the second proportion. The large armature copper losses are due to the extremely serious skin and squeezing effects. The analysis and test results are benefit for estimating the required inertial energy storage. Finally, the design aspects about the losses of pulsed HIA are discussed, and it is helpful for the optimal design of a high-efficiency pulsed HIA for capacitor charge power supply.