Optimal Power Values Research Articles

Tracking System on Solar Panels Using Microcontroller

Solar energy is a renewable energy that has not been widely implemented in a mass manner. To optimize the use of a solar panel, usually a control system that can adjust the position of the solar panel automatically is employed to get the optimal power value. This prototype tracking system of solar panels is dynamically following the direction of sunlight. The supporting devices used in this prototype are LDR sensor, Servo, Arduino Uno, Ina219, Bread Boot Power Supply and solar cell which must be activated first to work. The servo will drive a 3D printing device that is connected to an LDR sensor that is sensitive to sunlight. The Ina219 component serves to absorb the intensity of the sun and convert it in terms of voltage (volts) and electric current (amperes). The energy absorbed by the solar panels in the form of voltage and electric current will be stored in the battery so that it can turn on the lights. The solar panel prototype will be placed in an open area to get optimal solar energy compared to static solar panels.

Short-term scheduling of hybrid thermal, pumped-storage, and wind plants using firefly optimization algorithm

This paper presents a novel method based on an enhanced firefly algorithm (EFA) to solve scheduling hybrid thermal, pumped-storage, and wind plants. Since the scheduling problem is inherently discrete, basic EFA and binary encoding/decoding techniques are used in the proposed EFA approach. Optimal power values of thermal and pumped-storage units are determined separately in the presence of uncertainty caused by wind speed. The proposed method is applied to a real plant, including four pumped-storage units, 34 thermal units with different characteristics, and one wind turbine plant. In addition, dynamic constraints of upstream and downstream sources and constraints regarding thermal and wind units are also considered for finding the optimal solution. In addition, the proposed EFA is successfully applied to a real plant, and the results are compared with those of the three available methods. The results show that the proposed method has converted to a more optimal cost than the other methods.

Large-Sized GaN Crystal Growth Analysis in an Ammonothermal System Based on a Well-Developed Numerical Model.

The ammonothermal method is considered the most promising method of fabricating bulk gallium nitride (GaN) crystals. This paper improves the ammonothermal growth model by replacing the heater-long fixed temperature boundary with two resistance heaters and considering the real thermal boundary outside the shell. The relationship between power values and temperatures of dissolution and crystallization is expressed by the backpropagation (BP) neural network, and the optimal power values for specific systems are found using the non-dominated sorting genetic algorithm (NSGAII). Simulation results show that there are several discrepancies between updated and simplified models. It is necessary to build an ammonothermal system model with resistance heaters as a heat source. Then large-sized GaN crystal growth is analyzed based on the well-developed numerical model. According to the simulation results, both the increasing rate and maximum stable values of the metastable GaN concentration gradient are reduced for a larger-sized system, which is caused by the inhomogeneity of heat transfer in the autoclave.

Energy-Efficient Joint Task Assignment and Power Control in Energy-Harvesting D2D Offloading Communications

In this article, we investigate the joint task assignment and power control problems for Device-to-Device (D2D) offloading communications with energy harvesting. Exploiting the D2D links for data offloading allows reducing the traffic load of the cellular base stations. The energy consumed by the D2D transmitters for data offloading can be compensated by energy harvesting. The main objective is to maximize the energy efficiency (EE) under energy causality and delay constraints, assuming a harvest–transmit model. Hence, the proposed model results in a nonconvex problem. We first derive an equivalent and more tractable optimization problem by exploiting nonlinear fractional programming, also known as the Dinkelbach method. We propose a layered optimization method by decoupling the EE maximization problem into power allocation and offloading assignment. The first step consists of computing the optimal power values by applying the conjugate gradient method. In the second step, the problem of the D2D pair formation for data offloading amounts to the bipartite graph matching. It can be solved to optimality using the Hungarian algorithm. Extensive simulations were performed on various network scenarios. Numerical results show that the proposed resource allocation scheme achieves remarkable improvements in terms of network EE.

Time response of spin-polarized rubidium thermal gas with radio-frequency pulse driving

The time evolution of the polarization of a rubidium atom spin ensemble driven by a resonant radio-frequency (RF) magnetic field is analyzed based on the rate equation. A simple optical pumping experimental system is constructed and the time response of the rubidium atomic ensemble is demonstrated by recording the transmitted intensity of pumping light. In the steady-state response, the polarization difference between the optical pumping steady state and the magnetic resonance steady state depends on the optical pumping power and RF magnetic intensity. We can obtain the optimal power value corresponding to the maximum polarization difference. In terms of transient response, where the intensity of RF magnetic field is too weak to observe Rabi oscillations, two decay processes between magnetic resonance and optical pumping steady states are monitored. The decay time from magnetic resonance steady state to optical pumping steady state depends on the optical pumping rate and the spin relaxation rate. The decay time from optical pumping steady state to magnetic resonance steady state depends on the optical pumping rate, the RF driving rate, and the spin relaxation rate. The scale factor of pumping rate to pumping power is obtained, in addition to that of RF driving rate to the RF magnetic field. It can provide an intuitive understanding of the spin dynamic evolution of the polarized atomic ensemble.

Influence of process parameters in additive manufacturing of highly reinforced 316L / SiCp composites

Highly reinforced 316 L / SiCp metal matrix composites (MMC) walls have been additively manufactured by Direct Laser Deposition (DLD) using mixtures with different percentages of 316 L stainless steel powder and SiC particles (SiCp). The effect of the percentages of SiCp of up to 80 wt.% and DLD conditions on the geometry, microstructure, and hardness of the fabricated structures have been analyzed. SiC particles react with the molten 316 L steel and chromium and iron carbides are formed, and also graphite flakes and nodules are formed in the matrix. This reaction is also responsible for the dilution of the SiCp, which lose their initial shape and size. The incorporation of higher percentages of SiCp reduces the degradation of the particles as the matrix saturates in Si and C, and also enhances the size of the graphite precipitated phases. The different phases formed help to increase the hardness of the composites, and a maximum value of 1085 HV 0.1 was obtained for 40 vol.% of SiCp. Increasing further the amount of SiCp reduced the hardness to values of ∼890 HV 0.1 as the matrix is saturated in carbides and bigger and more brittle graphite precipitates are formed. The characteristics of the manufactured samples for the different reinforcement percentages used and for the different manufacturing conditions have been analyzed. From this study, the DLD processing maps for the 316 L/SiC MMC metal matrix composites with different content of reinforcement have been developed, and the optimal values of laser power, scanning speed, and layer height have been determined, and it has been observed that the optimum fabrication conditions displace to lower scanning speed for higher SiCp contents in the 316 L matrix. Showing that it is possible to manufacture cermets based on steel with lower density and greater hardness than the steel used.

Switchable Capacitor Bank Coordination and Dynamic Network Reconfiguration for Improving Operation of Distribution Network Integrated with Renewable Energy Resources

Point of common coupling (PCC) arrays are the most prominent and widely-used intermittent distributed generations (DGs). Due to the right-of-way, environmental, economical and other restrictions, the connection of these types of DGs to the preferred point of the distribution network is very difficult or impossible in some cases. Therefore, because of non-optimal locations, they may cause a voltage rise at the PCC. In this paper, a coordinated design of switchable capacitor banks (SCBs) with dynamic reconfiguration of the distribution network is proposed to avoid low- and high-voltage violations. The distribution network reconfiguration is implemented to mitigate the voltage rise at PCCs and capacitor banks (CBs) to solve the low-voltage problem. A novel method is presented for determining the optimal size of CBs. The proposed capacitor sizing method (CSM) effectively determines the optimal values of reactive power for the given nodes. The optimal locations of SCB are determined using particle swarm optimization algorithm. The 24-hour reactive power curve optimized by the proposed method plays a pivotal role in designing SCBs. The simulation results show that the implementation of the dynamic network reconfiguration and the placement of SCB is required to maintain a standard voltage profile for better employment of DG embedded distribution networks.

MAXIMUM POWER POINT TRACKING PADA IRADIASI DAN SUHU BERFLUKTUASI BERBASIS FUZZY TYPE-2

The potential of solar energy in Indonesia can be utilized as renewable energy and become one of the main alternative energy sources for power generation. The characteristics of solar panels will change depending on radiation levels and temperatures causing the power output of solar panels to fluctuate and become unstable. To reduce oscillations in output power, a study is needed to maximize the output power on solar panels, namely by using the Maximum Power Point Tracking (MPPT) method by using DC - DC circuits in the form of Cuk Converters using fuzzy type 2 controls to get optimal power values on the output. Test results using MATLAB / SIMULINK showed that in model 1 when irradian conditions 1000W / m2 with a temperature of 25 oC using Fuzzy Type 1 the accuracy obtained is 97.5% and using Fuzzy Type 2 the accuracy obtained is 100.2%. In model 2 when irradian conditions 1000 W / m2 with a temperature condition of 40oC using Fuzzy Type 1 the accuracy obtained is 94.3% and using Fuzzy Type 2 the accuracy obtained is 93.1%.

Optimization of the processing parameters in laser sharpening of bronze-bonded diamond grinding wheels

In this paper a new contribution to the optimization of processing parameters in the process of laser sharpening grinding wheels is presented. In the establishment of the three-dimensional heat conduction model, the laser heat source model is improved and the temperature field of the pulsed laser ablation material is obtained. The effects of laser power, laser line spot overlap ratio and laser scanning track overlap ratio on the sharpening efficiency and accuracy have been studied through the established numerical model. Like what happened in the actual machining process, the morphology of the bond material surface after laser sharpening was obtained by the simulation. The results show that the optimal values of laser power, laser line spot overlap ratio and laser scanning track overlap ratio are 20 W, 70%, and 70%, respectively. The simulation results have been verified and compared with the experimental results, revealing a good correlation between the simulation and experimental data. In a word, the numerical model established in this paper can be conveniently used in the optimization of the process parameters in the laser sharpening grinding wheel.

ANALISIS EKSERGI DAN OPTIMASI PEMBANGKIT LISTRIK TENAGA PANAS BUMI LAHENDONG UNIT-2

Geothermal development is carried out by increasing the efficiency of existing generators. In this study, geothermal development at the Lahendong Unit-2 geothermal power plant is carried out by conducting exergy analysis and optimizing geothermal plant efficiency using a genetic algorithm by adjusting the pressure on the separator. Exergy calculations and optimization of genetic algorithms, using the Python programming language with the help of libraries such as PyXSteam, Pandas, Numpy, matplotlib, random, and time. Exergy flow and efficiency are calculated on the components of the separator, turbine, condenser, cooling tower, and the entire plant. The amount of exergy that enters the generator from geothermal fluids is 28882.73 kW. The amount of exergy that comes in produces an output power of 13,000 kW with an overall efficiency of the generator is 45.010%, and the amount of exergy from brine is 1794.11 kW. Optimization using the genetic algorithm method produces the most optimal output power value of 13035,480445 kW at a separator pressure of 10.4025 bar. The increased quality of the steam generates this increase in power so that the mass flow rate of the steam that rotates the turbine becomes more than before.

Energy-aware node selection scheme with friendly jamming technique for enhancing the secrecy of wireless powered sensor networks

This work studies the secrecy performance of wireless powered sensor networks (WPSNs) under eavesdropping attacks by proposing an energy-aware node selection algorithm. The non-identical N sensor nodes harvest the required energy from a dedicated power station and use it for data transmission to a certain destination. The nodes selection procedure takes place over two phases. In the first phase, K nodes out of the total number of N nodes are selected under the condition that they succeed to harvest sufficient energy for transmission from the power station. In the second phase, among the selected K nodes from the first phase, two nodes are chosen in each time slot. The node with best channel conditions is selected for data transmission to the base station, while the other node that has the worst channel state acts as a cooperative jammer for the eavesdropper. We derive exact and asymptotic closed-form expressions for the secrecy outage probability (SOP) over Nakagami-m fading channels. Moreover, a power allocation problem is formulated to get the optimal uplink power values by minimizing the exact SOP expression using particle swarm optimization (PSO). Numerical results are obtained to validate our proposed model, followed by the conclusion to show its effectiveness.

Estimation of the spatial climate comfort distribution using tourism climate index (TCI) and inverse distance weighting (IDW) (case study: Fars Province, Iran)

This article was conducted to perform a temporal and spatial analysis in order to identify suitable climatic regions for tourism. We investigated tourism climate conditions in Fars province from 2006 to 2016 using tourism climate index (TCI). Also, modified inverse distance weighting (IDW) interpolation is applied to generate the optimal spatial pattern of the TCI distribution. The relationship between the interpolation accuracy and a critical IDW parameter, called power value (β), was evaluated for optimization. The results revealed that during four months of May, April, October, and November, 70–83% of cities in Fars province show excellent and ideal climatic comfort. In the four months of July, December, January, and March, about 45–54% of Fars province provide good and very good conditions for tourism activities. The spatial distribution of TCI also shows that the cities in the northern part generally have the most desirable conditions during the hot season, while the southern cities of Fars province are more suitable for tourism during the cold season. Also, analysis of optimization steps demonstrated that power value (β) affects interpolation accuracy. As our study suggests, using the optimal power values (β) of 1 and 2 can lead to optimal spatial interpolation of the TCI distribution. Overall, we found IDW and TCI as reliable tools for assessing bioclimatic comfort conditions, considering β-value as an influential factor that should be evaluated to achieve optimal interpolation results.

Impact of the penetration of distributed generation on optimal reactive power dispatch

Optimal reactive power dispatch (ORPD) is a complex and non-linear problem, and is one of the sub-problems of optimal power flow (OPF) in a power system. ORPD is formulated as a single-objective problem to minimize the active power loss in a transmission system. In this work, power from distributed generation (DG) is integrated into a conventional power system and the ORPD problem is solved to minimize transmission line power loss. It proves that the application of DG not only contributes to power loss minimization and improvement of system stability but also reduces energy consumption from the conventional sources. A recently proposed meta-heuristic algorithm known as the JAYA algorithm is applied to the standard IEEE 14, 30, 57 and 118 bus systems to solve the newly developed ORPD problem with the incorporation of DG. The simulation results prove the superiority of the JAYA algorithm over others. The respective optimal values of DG power that should be injected into the four IEEE test systems to obtain the minimum transmission line power losses are also provided.

Optimization of electrical networks modes by transformer ratios

The problem of optimization the modes of electrical networks pro- vides determination the optimal values of reactive power of sources, voltages of reference nodes and transformation ratios of controlled transformers. At pre- sent, methods and algorithms for optimization of reactive power and node volt- ages are sufficiently developed. However, the development of new efficient optimization algorithms of transformation ratios remains as a important topic. In this case, the issues of optimization of transformation ratios of transformers included in closed networks have a particular importance. This paper provides an effective algorithm for optimization the modes of electrical networks on transformation ratios of controlled transformers. The results of research of its efficiency in the presence of transformers with phase-rotary and longitudinal control in the circuit are presented. It is shown that minimization of losses in closed electrical networks when optimizing transformation ratios occurs due to the rational distribution of power flows in the branches.

Hydroxy Gas (HHO) Supplement of Ethanol Fuel Mixture In A Single-Cylinder Spark-Ignition Matic-Engine

<p class="TTPAbstract">Hydroxy Gas (HHO) has been identified as an efficient alternative energy source. HHO is considered an alternative fuel. It can be applied alone or mixed with other kind of fuels in different ratios. In this analysis, the composition of HHO-ethanol was mixed in different variations. Ethanol-HHO was chosen because of its high-octane rating yet low exhaust emissions, and ease of obtaining from engine products. It has been applied on fuel prepared by mixing it with gasoline in various ratios (E30-HHO, E40-HHO, and E50-HHO). The ethanol-HHO mixture has been used in a single-cylinder 4-stroke spark machine for performance, by varying speed of engine from 4000 to 9000 RPM and by applying a platinum spark plug electrode type. In experiments, engine power, average effective pressure (MEP), specific fuel consumption (SFC), and thermal efficiency have been analyzed. The analysis of combustion is accomplished by taking a pressure cycle in the chamber, monitoring the automatic control of engine control unit (ECU) and ensuring utilization in the same parameters of the various fuels tested, in addition to the fuel injection time, which increases with increasing ethanol percentage. Optimal power, MEP and thermal efficiency values are obtained with ethanol-gasoline (E50-HHO) mixture which is operated at 7200 rpm, an increase of about 5% compared to gasoline. Significant reduction in SFC was observed using HHO-ethanol mixture, reduced by about 6% compared to gasoline.</p>

On Performance of Full-Duplex Decode-and-Forward Relay Systems with an Optimal Power Setting under the Impact of Hardware Impairments

In this paper, we analyze the performance of in-band full-duplex (IBFD) relay systems that use the decode-and-forward (DF) protocol at the relay under the impact of imperfect self-interference cancellation and hardware impairments. Three practical relay scenarios are considered in our analysis: (i) there is no direct link from the source to the destination; (ii) there is a direct link, but the signal from the source is considered interference; and (iii) there is a direct link, and the signal from the source is cooperatively combined with that from the relaying path. Specifically, we derive exact and asymptotic expressions for the outage probability (OP) of the IBFD system. Based on the OP, the exact expression for symbol error probability (SEP) is also derived. Moreover, in order to cope with the effect of imperfect self-interference cancellation (SIC) due to the full-duplex mode, we propose optimal and suboptimal power calculation methods for the relay to minimize the OP and SEP. A performance evaluation shows that the IBFD relay system is significantly affected by both imperfect SIC and hardware impairments. However, the optimal power values can help to improve the system performance, significantly.

Experimental study of optical power effect on the structure of fiber-optical diffuser obtained by fiber core melting

Subject of Research. The paper presents experimental findings of a fiber-optic diffuser structure formed by optical fiber melting. Method. An optical scheme of ytterbium fiber laser is demonstrated consisting of such main components as: a laser pump diode (980 nm, with power up to 30 W), an active GTWave fiber (24 m), and two fiber Bragg gratings with reflection coefficients of 100 % and 30 %. The presented ytterbium radiation source is used to form a periodic structure of microcavities inside the fiber core using the melting effect of the material. The described technology application provides the creation of scattering structures with a given period without removing the protective acrylate fiber coating. Thus, there is no need for the optical fiber re-coating with a polymer composition, and its strength characteristics are maintained. Main Results. The experimental setup developed during the study gives the possibility to record the scattering structure in the core of the optical fiber by destroying the material using laser radiation. In order to determine the dependence of the properties of the created structures on the input radiation power, a number of samples was obtained recorded for various radiation characteristics. It was established experimentally that with an increase of laser radiation power, the period of localization of microcavities decreases. At the same time, their sizes are reduced, and the uniformity of the structure increases. The optimal radiation power value for the scattering structure formation is established to be about 2 W. Practical Relevance. The studied scattering structures can be used in medical research, laser photodynamic therapy, laser pacemakers, fluorescence diagnostics, and also as a backlight for minimally invasive operations. The fiber optic diffuser can be applicable as a sensor of physical quantities, in particular, for measuring high temperatures, since the upper limit of the diffuser working temperature is comparable to the melting temperature of the optical fiber quartz part.

Adaptive mesh size (AMS) algorithm for energy efficiency maximisation in underlay D2D communication

The need to maximise energy efficiency (EE) for device-to-device (D2D) communication has become an urgent necessity for the fifth-generation wireless networks. In this study, the power allocation problem is considered for the cellular system underlaid with D2D users (DUs) to maximise the EE for the whole network. Firstly, the random distribution of DUs and cellular users (CUs) are described by utilising the homogeneous Poisson point process based on stochastic geometry. Secondly, successful transmission probabilities are deduced. Finally, the optimisation problem for maximising EE is formulated to determine the optimal power values for both D2D and CUs. An adaptive mesh size algorithm is suggested to solve the non-convexity of the EE optimisation problem. Simulation results prove that the suggested technique has the ability to accomplish the near-optimal EE. Furthermore, it has superior performance when compared with the related algorithms.

UAV-enabled data acquisition scheme with directional wireless energy transfer for Internet of Things

Low power Internet of Things (IoT) is suffering from two limitations: battery-power limitation of IoT nodes and inflexibility of infrastructure-node deployment. In this paper, we propose an Unmanned Aerial Vehicle (UAV)-enabled data acquisition scheme with directional wireless energy transfer (WET) to overcome the limitations of low power IoT. The main idea of the proposed scheme is to employ a UAV to serve as both a data collector and an energy supplier. The UAV first transfers directional wireless energy to an IoT node which then sends back the data packets to the UAV by using the harvested energy. Meanwhile, we minimize the overall energy consumption under conditions of balanced energy supply and limited overall time. Moreover, we derive the optimal values of WET time and data transmission power. After analysing the feasibility of the optimal WET time and data transmission, we design an allocation scheme based on the feasible ranges of data size level and channel-fading degree. The numerical results show the feasibility and adaptability of our allocation scheme against the varied values of multiple system parameters. We further extend our scheme to the multi-node scenario by re-designing energy beamforming and adopting multi-access mechanisms. Moreover, we also analyse the mobility of UAVs in the proposed scheme.

Power Allocation in 5G mmWave Networks with Massive MIMO and Block Diagonalization

In this paper, we consider an energy-efficient downlink power allocation problem of a massive multiple-input multiple –output (MIMO) system in cellular networks. We propose a new technique that uses block diagonalization (BD) precoding with massive MIMO in 5G networks that employs milli-meter wave (mmWave) channel matrix to reduce the level of interference. A power allocation algorithm is then introduced by increasing the energy efficiency (EE) of the system to obtain optimal downlink power values using sequential quadratic programming (SQP) algorithm. The results reveal that using BD reduces the interference level and hence, increases the energy.