Remote Power Supply Research Articles

Protection of the Island Microgrid Based on Ocean Energy

With the continuous development and utilization of Marine resources, the island’s developments get more and more attention of the state, however, the island's power supply is always a bottleneck restricting the development of its economy. Microgrid as a kind of effective supply and use of distributed generation of power system, provides an effective solution for remote island power supply. There is a big difference in output characteristic from the power system, for the distributed power mostly use power electronic interface, which provides barriers to the protection of microgrid. The paper first introduces the structure and control mode of island microgrid based on wave energy power and currents can power generation, energy storage power, then analyzes the fault characteristics of the microgrid under different control, lastly summarizes the existing two types of microgrid relay protection method: the traditional overcurrent protection method and digital network protection method based on the communication.

해상기상탑 설계에 관한 연구

A meteorological(met) tower is the first structure installed during the planning stages of offshore wind farm. The purpose of this paper is to design the met tower with tripod bucket type support structure and to install the sensors. The support structure consist of a central steel shaft connected to three cylindrical steel suction buckets which is more cheaper than monopile or jacket type. And the remote wind condition sensors and marine monitoring equipment, including adcp, pressure type tide gauge, wave height sensors, and scour sensors, remote power supply are installed. The manufactured met tower constructed on sea area which is in front of Gasa island. All of functions of met tower showed normal operation conditions and the wind data got by remote data collection system successfully.

A Study of Design and Application of Solar Energy Power Supply System in Highway Tunnel Lighting

In China, because it is difficult to pay the high electricity, resulting in a large number of highway tunnel illuminations is insufficient. In order to solve remote highway tunnel lighting power supply problem, we use the solar photovoltaic system, developed and built a solar lighting system in highway tunnel. This paper introduces the design and application process of this system.

Development of a Sensor Based Self Powered Smart Control System for Agricultural Irrigation Systems

Precision agriculture is combined with irrigation control systems to observe the environment and respond accordingly. In this paper, we discussed developmental procedure of a novel irrigation control system called Sensor Based Self-powered Smart Irrigation Control System (SSSICS). In the current market, there are several irrigation controllers available and they are either timer based open loop (OL) or sensor-based closed loop (CL) irrigation controllers. Each method has different advantages and disadvantages, and SSSICS contains OL and CL control techniques to get rid of disadvantages. We used OL control technique to work in the Timer Mode(TM) and CL control technique to work in the Intelligent Mode (IM). We introduced a new graphical user interface (GUI) as a human-machine interface (HMI). This HMI and available inputs facilitated the farmer to set precise environmental parameters required for the crop to give maximum yield. For remote farm fields, it is necessary to have a remote communication (RC) and uninterrupted power supply. Text messages that receive and send via Global System for Mobile (GSM) Communication allow the farmer/user to perform RC with the control system (CS) of the SSSICS. We designed a Micro Hydro Power Generator (MHPG) array and solar system including rechargeable batteries to give the power required to the SSSICS. The SSSICS was tested in real environment and it was demonstrated that hybrid power generation concept by incorporating open loop and closed loop control techniques works properly in the hardware platform developed for the study.

One-to-Multipoint Laser Remote Power Supply System for Wireless Sensor Networks

A method to use laser to supply power remotely for multinode wireless sensor networks is proposed in this paper. In the working space of wireless sensor networks, laser is transformed to a spatial distributed light field with certain uniformity and its wavelength is converted to the most sensitive wavelength of solar cell by the phosphor element. Thus, more wireless sensor networks nodes can be powered at the same time. A demonstration experiment is carried out, an yttrium aluminum garnet phosphor element is stimulated by the 3 W 457 nm laser and a uniform diffused light field with 3 π/4 space angle is obtained. The average optical energy density is 85 μ W/cm2 at the distance 1.5 m away from the phosphor surface. An ultra low-power consumption energy harvesting system is designed. Under the radiation of remote laser power supply, characteristics of the energy harvesting system are tested. The result is that the system can supply 92.1 mJ during 0.7 s which can provide enough energy for WSN node. Preliminary result of a real-life application in an oil cellar is also given. As a novel power supply method for wireless sensor networks, it is a good active power supply candidate for wireless sensor networks when the environment energy field is not strong enough.

Hydro energy: techno-economic and social aspects within new climate regime

Small hydro systems can provide electricity for: central-grid, isolated-grids, and/or remote power supplies. Small hydraulic power also provides an extra contribution to national electrical production in the case of consumption peaks. Although hydro is currently the second most used renewable energy source in the world, still there is a significant unexploited potential. The clean development mechanism (CDM) may act as an additional incentive for further diffusion in the developing world. This paper explains hydro energy techno-economics, followed by a description of the social and environmental implications of small-scale hydro. Moreover, the financing conditions for such projects are presented, as also an indicative set of case studies of small hydro projects in the developing world. Our research supports the argument that incorporating small hydro into an integrated sustainable energy strategy will serve the threefold energy policy objective of security of supply, environmental protection and competitiveness and significantly contribute toward achieving the Millennium Development Goals and sustainability.

Piezoelectric Micro-power Generation to Charge Supercapacitor with Optimized Duty Cycle

Energy harvesting has been proved to be a novel solution to replace the batteries in remote power supply applications. Unfortunately, the limited capacity and low efficiency of output power constraint the practical applications of energy harvesting in daily life. After a systematic review of previous researches about energy harvesting in power management perspective, a circuit design, which focuses on low-frequency mechanical vibration, is introduced. With classical piezoelectric cantilever configuration, the maximum charging current of a supercapacitor can be obtained by optimizing the duty cycle of a buck regulator through software implemented pulse width modulation. The results of experiments prove the capacitive electric model of the piezo, the existence of maximum charging current of the supercapacitor, and the adaptive control of the designed circuits. With the duty cycle optimized to 2.17%, the maximum charging current of 17.36 mA is measured, which is approximately four times fold of previous researches in similar vibration conditions. An active RFID application is proposed to utilize the harvested power of 67.2 µW.

Current Sensor Based Home Appliance and State of Appliance Recognition

This paper presents a current sensor-based home appliance and its state recognition method for intelligent outlets. Our system has three main functions: remote control, monitoring, and power supply schedule management. This research focuses particular on the monitoring function. To recognize the appliance and the state of the appliance, we extract ten features based on a measured current signal. In the experiment, we gather a number of signals with various appliances, and find that three features Irms, Iavg, and Ipeak yield valid recognition results of 84.3%, 86.4%, and 90.3% for classifying the state of the appliance into three categories. Moreover, sufficient recognition rates of 97.4%, 97.7%, and 99.0% are obtained by consideration of three candidates.

SOLAR 1.1: DEVELOPMENT OF SOFTWARE FOR SELECTING COMMERCIALLY AVAILABLE PHOTOVOLTAIC PANELS, INCLUDING THE ECONOMIC ANALYSIS

Photovoltaic energy represents an opportunity to produce electricity in a clean manner. It can be applied in all world places, in particular in the developing countries, where there are places where electricity grids are unreliable or non-existent and is inconvenient to make investments in a grids expansion. In remote locations photovoltaic power supplies often the most economic and cleaner option to produce electric energy. In addition, many developing countries have high radiation levels year round because of their latitude. The software SOLAR 1.1 was developed with purpose of helping the choice of photovoltaic panels available commercially including electric needs calculation for the installation. This new version of program also help to conduce the economic analysis for grid connected or stand alone photovoltaic systems for the choice of convenient values of interest rate and payback period. In this version of the software is possible to select the language among English, Italian and Portuguese. The software choices the panels in its archive that contains more of 250 types of photovoltaic modules made by 35 producers. The selection provides as output three modules, the cheapest for each cell type: monocrystalline, multicrystalline and amorphous. The software archive can be updated adding new item or editing the inserted items. The economic analysis can be operated by SOLAR 1.1 in each of the chosen panels. This analysis gives as output all the values of the costs in the photovoltaic system and the diagrams with the electricity cost and the expected annual saving trend with variation of the amortisation period and for different values of the interest rate and the governmental subsidy rate.

Energy and cost analysis of a solar-hydrogen combined heat and power system for remote power supply using a computer simulation

A simulation program, based on Visual Pascal, for sizing and techno-economic analysis of the performance of solar-hydrogen combined heat and power systems for remote applications is described. The accuracy of the submodels is checked by comparing the real performances of the system’s components obtained from experimental measurements with model outputs. The use of the heat generated by the PEM fuel cell, and any unused excess hydrogen, is investigated for hot water production or space heating while the solar-hydrogen system is supplying electricity. A 5 kWh daily demand profile and the solar radiation profile of Melbourne have been used in a case study to investigate the typical techno-economic characteristics of the system to supply a remote household. The simulation shows that by harnessing both thermal load and excess hydrogen it is possible to increase the average yearly energy efficiency of the fuel cell in the solar-hydrogen system from just below 40% up to about 80% in both heat and power generation (based on the high heating value of hydrogen). The fuel cell in the system is conventionally sized to meet the peak of the demand profile. However, an economic optimisation analysis illustrates that installing a larger fuel cell could lead to up to a 15% reduction in the unit cost of the electricity to an average of just below 90 c/kWh over the assessment period of 30 years. Further, for an economically optimal size of the fuel cell, nearly a half the yearly energy demand for hot water of the remote household could be supplied by heat recovery from the fuel cell and utilising unused hydrogen in the exit stream. Such a system could then complement a conventional solar water heating system by providing the boosting energy (usually in the order of 40% of the total) normally obtained from gas or electricity.

Wavelength Dependent Remote Power Supply for Shape Memory Alloy

The use of shape memory alloy (SMA) actuators in smart structures is increasing significantly especially in the field of Micro-Electro-Mechanical Systems (MEMS) due to their unique properties. In this work wavelength dependent remote power supply for SMA is presented to avoid electrical cables from the working area of the structure and to demonstrate the selective addressing of a high number of micro-actuators placed in a small space. Low power (∼100 mW) continuous mode laser diodes are used as remote power supply sources. A thermal numerical model is presented to visualize the temperature evolution in a Nitinol sample (3 mm × 1 mm × 100 μm) irradiated by 785 nm laser source. A series of experiments are performed to validate the modelling results, to estimate the response time under different loadings (15 g and 20 g) and to demonstrate the wavelength dependent deformation in SMA samples for selective addressing which is realized by depositing thin layers having specific optical filtering properties directly over the SMA sample and using laser diode sources with different wavelengths (785 nm and 658 nm).

Modelling and simulation of a novel micro-scale combined feedstock biomass generation plant for grid-independent power supply

Remotely located and sparsely populated areas often do not have access to an efficient grid connection for electricity supply. However, plenty of biomass is normally available in such areas. Instead of employing island solutions such as diesel generators or large battery stacks with severe impacts on both the environment and economics of rural electrification, a micro-scale biomass plant using locally available feedstock to produce electricity and/or heat is an efficient way of not only providing those areas with competitive and reliable electricity, but also a step towards energy self-sufficiency for a large share of areas worldwide. Both wet and dry feedstock are usually available in remote areas, therefore a novel plant design combining thermochemical and biochemical treatment has been developed. The system consists of a small-scale downdraft gasifier and an anaerobic digester unit, both coupled to a gas storage system and a microturbine as the generation unit. This combined feedstock design is suitable to provide electricity down to a level of around 50 kWe, which suits a remote village or a large farm. This paper covers the modelling of the plant design in chemical engineering simulation software. Additionally, feasibility studies and results obtained from operation simulations are described and show that such a system is a feasible and an economic solution for remote power supply.

Analysis, Design, and Control of a Transcutaneous Power Regulator for Artificial Hearts

Based on a generic transcutaneous transformer model, a remote power supply using a resonant topology for use in artificial hearts is analyzed and designed for easy controllability and high efficiency. The primary and secondary windings of the transcutaneous transformer are positioned outside and inside the human body, respectively. In such a transformer, the alignment and gap may change with external positioning. As a result, the coupling coefficient of the transcutaneous transformer is also varying, and so are the two large leakage inductances and the mutual inductance. Resonant-tank circuits with varying resonant-frequency are formed from the transformer inductors and external capacitors. For a given range of coupling coefficients, an operating frequency corresponding to a particular coupling coefficient can be found, for which the voltage transfer function is insensitive to load. Prior works have used frequency modulation to regulate the output voltage under varying load and transformer coupling. The use of frequency modulation may require a wide control frequency range which may extend well above the load insensitive frequency. In this paper, study of the input-to-output voltage transfer function is carried out, and a control method is proposed to lock the switching frequency at just above the load insensitive frequency for optimized efficiency at heavy loads. Specifically, operation at above resonant of the resonant circuits is maintained under varying coupling-coefficient. Using a digital-phase-lock-loop (PLL), zero-voltage switching is achieved in a full-bridge converter which is also programmed to provide output voltage regulation via pulsewidth modulation (PWM). A prototype transcutaneous power regulator is built and found to to perform excellently with high efficiency and tight regulation under variations of the alignment or gap of the transcutaneous transformer, load and input voltage.

Intrinsically Safe Supply System by Means of Multi-Pair Telecommunication Cables

Abstract The conditions of intrinsically safe power transmission to telecommunication devices and safety parameter control systems located in potentially explosive zones via a line track using central source of remote supply featuring linear and non-linear output characteristics was discussed in the present work. It was proved that, when applying such remote power supply featuring linear output characteristics, the application of line track with larger diameter of working wires would ensure neither a decrease of power losses on isolated resistance of line track nor an increase of remotely transmitted intrinsically safe power in a proportional way. As a more effective method appeared here the arrangement of remote intrinsically safe supply system using separate power transmission channels, i.e. several line tracks with a smaller diameter of working wires. The use of a protective system featuring non-linear output characteristics at the input of remote power transmission system would allow elimination of the influence exerted by the remote power supply upon formation of explosive mixture ignition core at the emergency commutation point, where a protective system ensuring separation of power generated by the power supply by shorting its output terminals would be more advantageous from the discharging energy minimization viewpoint.

Techno-economics of micro-hydro power plants for remote villages in Uttaranchal in India

Results of a techno-economic feasibility evaluation of some micro-hydro power (MHP) plants being planned and implemented for remote village power supply in the state of Uttaranchal in India are presented. The capital cost of MHP plants in the capacity range of 20–100 kW (including cost of local transmission and distribution system), investment requirement per unit of rated capacity, and relative cost of different components of MHP plants have been analysed. Unit cost of delivered electricity from the MHP plants has been estimated. Discounted payback period, benefit–cost ratio, net present value and internal rate of return for an MHP plant have also been determined. Breakeven values for useful life, plant load factor, and unit cost of electricity to the user for the same MHP plant have also been estimated.

A Control Circuit for a Microsensor Hybrid Power Supply

This paper presents a simple low-power control circuit intended to manage the power within a remote autonomous microsystem hybrid power supply. A hybrid power supply has only recently been discussed in the literature as a microsystem power source solution. The power management circuitry, which is a key component within a hybrid power supply, has not been adequately explored. Although a variety of components could have been implemented, the control circuit in this paper was designed for a hybrid power supply that utilizes a Ni/Zn microbattery and silicon solar cell. The circuit also employs a shunt architecture powered only by the solar cell to minimize the overall energy consumption of the hybrid power supply. The control circuit consumes a maximum of 7 /spl mu/A and appropriately manages power even when the hybrid power supply is connected to a microsystem and is experiencing environmental variations. Details of the control circuit are discussed and simulations combined with experimental results demonstrate its performance.

Damping as a result of piezoelectric energy harvesting

Systems that harvest or scavenge energy from their environments are of considerable interest for use in remote power supplies. A class of such systems exploits the motion or deformation associated with vibration, converting the mechanical energy to electrical, and storing it for later use; some of these systems use piezoelectric materials for the direct conversion of strain energy to electrical energy. The removal of mechanical energy from a vibrating structure necessarily results in damping. This research addresses the damping associated with a piezoelectric energy harvesting system that consists of a full-bridge rectifier, a filter capacitor, a switching DC–DC step-down converter, and a battery. Under conditions of harmonic forcing, the effective modal loss factor depends on: (1) the electromechanical coupling coefficient of the piezoelectric system; and (2) the ratio of the rectifier output voltage during operation to its maximum open-circuit value. When the DC–DC converter is maximizing power flow to the battery, this voltage ratio is very nearly 1/2, and the loss factor depends only on the coupling coefficient. Experiments on a base-driven piezoelectric cantilever, having a system coupling coefficient of 26%, yielded an effective loss factor for the fundamental vibration mode of 2.2%, in excellent agreement with theory.

Adaptive piezoelectric energy harvesting circuit for wireless remote power supply

This paper describes an approach to harvesting electrical energy from a mechanically excited piezoelectric element. A vibrating piezoelectric device differs from a typical electrical power source in that it has a capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. An analytical expression for the optimal power flow from a rectified piezoelectric device is derived, and an "energy harvesting" circuit is proposed which can achieve this optimal power flow. The harvesting circuit consists of an AC-DC rectifier with an output capacitor, an electrochemical battery, and a switch-mode DC-DC converter that controls the energy flow into the battery. An adaptive control technique for the DC-DC converter is used to continuously implement the optimal power transfer theory and maximize the power stored by the battery. Experimental results reveal that use of the adaptive DC-DC converter increases power transfer by over 400% as compared to when the DC-DC converter is not used.

Micromagnetic actuators

SUMMARYRecent topics in the development of micromagneticactuators in Japan are reviewed. Electromagneticmicroactuators less than 1 mm in diameter, e.g.micromotor, and microvalves have been fabricated andtheir high performance has been demonstrated. A newtype microactuator based upon magnetostriction has alsobeen developed and has shown a large cantileverdeflection. In addition, some models of the microrobotsusing micromagnetic actuators were able to move using awireless remote power supply.

95/03777 Photovoltaic systems for small-scale remote power supplies

95/03777 Photovoltaic systems for small-scale remote power supplies