scholarly journals Mini Wind Harvester and a Low Power Three-Phase AC/DC Converter to Power IoT Devices: Analysis, Simulation, Test and Design

2020 ◽  
Vol 10 (18) ◽  
pp. 6347
Author(s):  
Borja Pozo ◽  
José Ángel Araujo ◽  
Henrik Zessin ◽  
Loreto Mateu ◽  
José Ignacio Garate ◽  
...  

Wind energy harvesting is a widespread mature technology employed to collect energy, but it is also suitable, and not yet fully exploited at small scale, for powering low power electronic systems such as Internet of Things (IoT) systems like structural health monitoring, on-line sensors, predictive maintenance, manufacturing processes and surveillance. The present work introduces a three-phase mini wind energy harvester and an Alternate Current/Direct Current (AC/DC) converter. The research analyzes in depth a wind harvester’s operation principles in order to extract its characteristic parameters. It also proposes an equivalent electromechanical model of the harvester, and its accuracy has been verified with prototype performance results. Moreover, unlike most of the converters which use two steps for AC/DC signal conditioning—a rectifier stage and a DC/DC regulator—this work proposes a single stage converter to increase the system efficiency and, consequently, improve the energy transfer. Moreover, the most suitable AC/DC converter architecture was chosen and optimized for the best performance taking into account: the target power, efficiency, voltage levels, operation frequency, duty cycle and load required to implement the aforementioned converter.

2019 ◽  
Vol 8 (4) ◽  
pp. 9557-9562

Wind energy is one of the most viable options for clean and sustainable energy production. In Malaysia where wind source has been considered scarce, the capacity of installed wind energy production is very low. However, studies have shown that it is worthwhile to produce wind energy at several potential sites in this country. For this purpose, it is crucial that the designed turbine blade gives the highest possible blade power efficiency while structure wise, the turbine blade need to be effective in terms of avoiding possible failures. The maximum power efficiency means the blade does not only provide profile that gives maximum sliding ratio but also it must operate at the corresponding angle of attack, 𝜶𝒎𝒂𝒙 that gives this ratio. At the same time, the blade must be small enough to have low weight to allow it to self-start in the low wind region. In this paper, the study is focused on the aerodynamic aspect of the design of wind turbine blade that will give the maximum power efficiency. Four factors that determine aerodynamic performance of the turbine blades are discussed: the wind condition, the airfoil profile, the blade geometry and the losses. In most of the factor, adjustments are made such that the blade operates at around the 𝜶𝒎𝒂𝒙 so that the sliding ratio and thus power coefficient are maximum.


Electronics ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 151 ◽  
Author(s):  
Umut Güvengir ◽  
Işık Çadırcı ◽  
Muammer Ermiş

This paper is devoted to an otablen-line application of the selective harmonic elimination method (SHEM) to three-phase, two-level, grid-connected voltage source converters (VSCs) by particle swarm optimization (PSO). In such systems, active power can be controlled by the phase shift angle, and reactive power by the modulation index, against variations in the direct current (DC) link voltage. Some selected, low-odd-order harmonic components in the line-to-neutral output voltage waveforms are eliminated by calculating the SHEM angle set continuously through the developed PSO algorithm on field-programmable gate array (FPGA)-based computing hardware as the modulation index is varied. The use of powerful computing hardware permits the elimination of all harmonics up to 50th. The cost function of the developed PSO algorithm is formulated by using an optimum number of particles to obtain a global optimum solution with a small fitness value in each half-cycle of the grid voltage and then updating the SHEM angle set at the beginning of the next full-cycle. Since the convergence of the solution to a global minimum point depends upon the use of correct initial values especially for a large number of SHEM angles, a generalized initialization procedure is also described in the paper. Theoretical results are verified initially using hardware co-simulation. They are also tested using a small scale photovoltaic (PV) supply prototype developed specifically for this purpose. It is demonstrated that the 5th, 7th, 11th, 13th, 17th, and 19th sidekick harmonics are eliminated by on-line calculation of seven SHEM angles through the developed PSO algorithm on a moderately powerful XEM6010-LX150, USB-2.0-integrated FPGA module. All control and protection actions and the calculation of SHEM angles are achieved by a single FPGA chip and its peripherals within the FPGA board.


Author(s):  
Ace Dimitrievski ◽  
Sonja Filiposka ◽  
Francisco José Melero ◽  
Eftim Zdravevski ◽  
Petre Lameski ◽  
...  

Connected health is expected to introduce an improvement in providing healthcare and doctor-patient communication while at the same time reducing cost. Connected health would introduce an even more significant gap between healthcare quality for urban areas with physical proximity and better communication to providers and the portion of rural areas with numerous connectivity issues. We identify these challenges using user scenarios and propose LoRa based architecture for addressing these challenges. We focus on the energy management of battery-powered, affordable IoT devices for long-term operation, providing important information about the care receivers’ well-being. Using an external ultra-low-power timer, we extended the battery life in the order of tens of times, compared to relying on low power modes of the microcontroller.


IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 22558-22568
Author(s):  
Casper J. J. Labuschagne ◽  
Maarten J. Kamper

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