Terms Of Output Power Research Articles

Power output enhancement of grid-connected PV system using dual-axis tracking

The current paper proposes an augmentation of power output production of a single-phase grid-connected photovoltaic (PV) system using dual-axis solar tracking (DAST). Solarius PV software was applied to design and predict the energy demand for a single-family house over one year under the climate condition of Basra city, Iraq. The performance of the DAST-PV system was compared to another stationary PV system has the same capacity in terms of power output and the reduction of generated emissions over 20 years lifetime. The results showed that the stationary PV system can overcome up to 84.8% of the total electricity demand of the house while DAST-PV system can overcome up to 100% with surplus energy of 9886.55 kWh. Moreover, the greenhouse gases (GHGs) emissions avoided by the DAT-PV system were about 34.8% more than the stationary system over the system lifetime.

Skin Temperature Elevation for Incident Power Densities From Dipole Arrays at 28 Ghz

The relationship between skin temperature elevation and incident power density (IPD) from radio-frequency near-field exposure at 28 GHz for different angles of incidence is evaluated computationally in this study. The averaging scheme of the IPD is crucial for determining the maximum allowable exposure levels of wireless equipment to comply with certain standards/regulations. However, it is still unclear which component of the IPD (i.e., the norm or normal component to the human body) is more related the temperature elevation. In the case of four-element dipole arrays, the distances between the model and the antenna were 15 and 30 mm in transverse-electric- and transverse-magnetic-like polarized waves, respectively, and in the case of eight-element dipole arrays, the distances were 45 mm from the center of the array. From our computational results for four- and eight-element dipole arrays, we confirmed that the normal component of the IPD provides better correlation with the surface skin temperature, regardless of angle of incidence, particularly for smaller angles of incidence (<30°). The enhancement of the ratio of the temperature increase to IPD was observed around the Brewster’s angle, which is mainly attributable to the difference in transmittance at the body surface. This exposure scenario may not occur as the antenna–human distance was too large to consider compliance at the closest distance. In terms of output power, the most restrictive condition for compliance is shown to be normal incidence, suggesting the importance of compliance for such exposure scenarios. Furthermore, the absorbed power density proved to be an appropriate metric to monitor in relation to skin temperature elevation.

Cold‐test of reltron modulation section and PIC simulation study on output power and efficiency

Parametric analysis and cold test of reltron modulation section are presented along with particle-in-cell (PIC) simulation results. A cavity is designed to have maximum separation among the three resonant modes 0, π/2, and π. Electromagnetic (EM) simulation software packages CST Microwave Studio (MWS) and MAGIC are used to obtain and compare the electromagnetic field patterns and resonant frequencies. Both the software predict the modes with identical field pattern and a difference of 1.3% to 3.8% in resonant frequency. The MAGIC code used here captures all three modes successfully. The designed cavity is fabricated and S11 is measured. The frequencies of measured S11 minima differ by 1.6% to 3.5% from the simulated values and closely match with that of the resonant modes. Furthermore, the modulation section is parametrically studied to observe the dependence of the resonant frequencies on the physical dimensions. The key parameters that govern the operating frequency and mode separation are identified. The Q factors are calculated from S11, and after that, the cavity reactance from loaded Q. Particle-in-cell (PIC) simulation results indicate that the mode separation improves overall system performance in terms of output power and efficiency.

Hardware Testing of New MPPT Method under Various Environmental Conditions

There are different MPPT techniques to track the maximum power point. When a PV system is directly connected to the load the operating point seldom lies in the maximum power point, whereas it lies at some other point. Thus the effective utilization of PV cannot be done. But using MPPT techniques the system is always made to operate at peak point irrespective of any changes in atmospheric condition. The Proposed method gives better result in terms of output power and hence efficiency of the converter. This method is a tradeoff between steady state accuracy and dynamic tracking by using variable step size instead of fixed step size as like P and O method. The system gives very poor performance when connected directly without mppt. An experimental analysis was conducted to validate the effectiveness of the proposed MPPT method. The proposed method was compared with the conventional Perturb and Observance method and was found that for every environmental conditions like, change in irradiance, angle of tilt, shading, soiling, colour filter, mounting the proposed method gives better power output and efficiency than P and O method. Hardware testing is done to analyze the method.

Fuzzy Logic Controlled SEPIC Re-Lift Converter System - A Comparative Study

Voltage lift cascaded DC/DC converters are generally used to feed low power DC drives and batteries. This paper deals with the modelling, the simulation and the comparison of voltage lifted Single Ended Primary Inductor Converter (SEPIC) cascaded soft switched converter systems. The objective of this work is to improve the voltage gain and the efficiency of the voltage lifted SEPIC converter. Auxiliary switch with capacitor clamping is added in order to obtain the soft switching. SEPIC in self-lift and re-lift modes are simulated and the corresponding results are presented. The performance of the converter is studied in terms of output power and ripple voltage. Design and simulation results are presented in order to identify a cascaded system with high power output. The comparative study is presented in order to demonstrate the reduction in the ripple in the output voltage. The advantages of the proposed converter are high voltage gain, reduced switching loss and low electromagnetic interference (EMI). The open loop systems with fluctuating input voltages are simulated. Closed loop systems with proportional integral controller and Fuzzy Logic Controller (FLC) are simulated and their results are compared. Comparing the results, it can be observed that the time response has been improved in terms of settling time and steady state error.

Experimentation on Design and Development of Mini Wind Turbine

Wind energy systems are energized by the naturally flowing wind, therefore it can be considered as a fresh source of energy. In addition, the wind energy is accessible as a domestic source of power in many countries worldwide and not bound to just a couple of nations, as on account of oil. However, the output of a wind turbine relies on upon the turbine's size and the wind's speed through the rotor. The amount of power created by the horizontal axis wind turbine is proportional to rotor area and power of wind velocity. In present paper the experimental and analytical study with finite element analysis has been carried out with considering dependent factors like wind speed, number of blades, size of blades to evaluate maximum output power. It is observed that, the eight numbers of blades with 1200mm diameter is more effective in terms of power output.

Low phase‐noise high output power 176‐GHz voltage‐controlled oscillator in a 130‐nm BiCMOS technology

In this study, the authors present the design and measurement results of a voltage-controlled oscillator (VCO) that is based on a Colpitts core topology and a cascade output buffer. The circuit has a centre frequency of 176 GHz and is implemented in a 130 nm SiGe BiCMOS technology provided by IHP foundry. The VCO is a differential fundamental wave tunable oscillator that makes use of a transistor-based LC-resonator. On-wafer measurements show a tuning range of about 5% from 171 to 179.5 GHz. The circuit achieves a maximum output power of 7.3 dBm when biased at 1.6 V and 6.5 dBm if biased at 1.4 V, both with an efficiency of ∼ 6.6%. DC power consumption is 82 and 52 mW, respectively. The measured phase-noise of the VCO is − 110 dBc/Hz at 10 MHz offset. The VCO demonstrates state-of-the-art performance at these frequencies with very good performance in term of output power, efficiency linearity, phase noise and compactness; in addition, thanks to the proposed architecture it shows high integrability at the system level.

Bragg Grating Diffraction light at Different Wavelength and Incident Light

The diffraction grating is an important device that makes use of the diffraction of light to produce spectra. Diffraction is also fundamental in other applications such as x-ray diffraction studies of crystals and holography. We proposed a design of Bragg grating waveguide to investigate the behavior of diffraction of light at different incident angle and wavelengths. Using finite difference time domain (FDTD) photonics simulation software the performance of proposed waveguide is observed in term of output power, electric field, diffraction efficiency (DE) and signal to noise ratio (SNR). It is found that the proposed waveguide provides better diffracted light with electric field distribution with 1.969 v/m, Diffraction efficiency 8%, and SNR (25.5 dB) at 1.55µm wavelength and 00 degrees of incident angle

Solar chimney power plants – Dimension matching for optimum performance

Solar chimney power plants are very large structures with the potential to generate significant amounts of electricity. Plant dimensions such as the collector diameter and chimney height and radius are important in determining system performance. The objective of this study is to identify the key parameters that drive performance. Performance was assessed in terms of power output and power output per cost. Using a detailed thermodynamic model, the plant power output was predicted for a wide range of design and operational parameters. It was found that the optimum pressure drop ratio depends on the collector and chimney radius, but not on chimney height, ambient temperature or insolation. The dimensions of the main components must be well matched to achieve best performance. Chimney radii of up to 200 m are essential to achieve maximum power generation up to 900 MW. Optimum power output exists for variation of the collector and chimney radius. However, increasing the chimney height always results in increased power generation. The physical phenomena underpinning high-performing configurations were highlighted. Power and efficiency increase with increased plant dimensions, but technological limits exist for the chimney height. A simple but robust cost model was introduced to identify optimum configurations in terms of power output per cost. Different relative costs between collector and chimney the optimum dimensions were selected. It was concluded that several smaller plants with collector radius about 3000 m are advantageous over one larger plant. Taller chimneys are economically beneficial until the specific chimney costs increase more than quadratically with height.

DC-DC Converter Topologies for Electric Vehicles, Plug-in Hybrid Electric Vehicles and Fast Charging Stations: State of the Art and Future Trends

This article reviews the design and evaluation of different DC-DC converter topologies for Battery Electric Vehicles (BEVs) and Plug-in Hybrid Electric Vehicles (PHEVs). The design and evaluation of these converter topologies are presented, analyzed and compared in terms of output power, component count, switching frequency, electromagnetic interference (EMI), losses, effectiveness, reliability and cost. This paper also evaluates the architecture, merits and demerits of converter topologies (AC-DC and DC-DC) for Fast Charging Stations (FCHARs). On the basis of this analysis, it has found that the Multidevice Interleaved DC-DC Bidirectional Converter (MDIBC) is the most suitable topology for high-power BEVs and PHEVs (&gt; 10kW), thanks to its low input current ripples, low output voltage ripples, low electromagnetic interference, bidirectionality, high efficiency and high reliability. In contrast, for low-power electric vehicles (&lt;10 kW), it is tough to recommend a single candidate that is the best in all possible aspects. However, the Sinusoidal Amplitude Converter, the Z-Source DC-DC converter and the boost DC-DC converter with resonant circuit are more suitable for low-power BEVs and PHEVs because of their soft switching, noise-free operation, low switching loss and high efficiency. Finally, this paper explores the opportunity of using wide band gap semiconductors (WBGSs) in DC-DC converters for BEVs, PHEVs and converters for FCHARs. Specifically, the future roadmap of research for WBGSs, modeling of emerging topologies and design techniques of the control system for BEV and PHEV powertrains are also presented in detail, which will certainly help researchers and solution engineers of automotive industries to select the suitable converter topology to achieve the growth of projected power density.

Employing thermoelectric generator and booster compressor for performance improvement of a geothermal driven combined power and ejector-refrigeration cycle

This paper aims at performance improvement of conventional combined power and ejector refrigeration (CPER) system driven by geothermal energy. To do so, two novel systems are proposed and their performance is modeled, investigated and compared with each other as well as with the conventional CPER system. In the proposed systems a booster compressor is employed between the evaporator and ejector to increase the output cooling, and thermoelectric generator (TEG) is employed for waste heat recovery to increase the output power. To analyze the conventional and the proposed CPER systems from the energy and exergy perspectives, thermodynamic models are developed, after which a comprehensive parametric study is conducted to examine the effects of design/operating variables on the systems’ performance. The results revealed that, proposed booster assisted system incorporated with TEG has a significantly better performance than the conventional CPER system in terms of output power and cooling as well as energy and exergy efficiencies. However, the proposed booster assisted system without incorporating TEG has a lower values of output power and exergy efficiency than the conventional CPER system, while it yields higher values of output cooling and energy efficiency. It is found that, the booster assisted system incorporated with TEG yields higher exergy efficiency by around 18.7% than the conventional CPER system.

Internal Resistance Computation of a Cylindrical LCO Battery for Heat Generation Model

The internal resistance is one of the most important parameters which directly relate to battery performance in terms of output power and heat generation. This research presents the internal resistance of the battery that is studied with using battery voltage behaviour. Lithium Cobalt Oxide (LiCoO2, LCO) battery is applied for the experiment. The voltage drop during the current discharge is calculated to obtain internal resistance by the current pulse technique (CPT). Three different terms of internal resistance are compared by the voltage drop characteristic. As the result, comparison of temperature profile between experiment and simulation was obtained by current pulse technique with discharge rate variations.

Analysis of Four Wave Mixing In Ultra Dense WDM-Hybrid Optical Amplifier Systems

Abstract Amplification through hybrid optical amplifiers (HOAs) is a propitious and proficient technology for high speed and high capacity dense wavelength-division-multiplexing (DWDM) systems. HOAs are intended to improve system reach and to accomplish wide gain bandwidth with enhanced flatness of gain. In this work, an ultradense 16 channel WDM system is demonstrated and performance of diverse hybrid amplifiers is evaluated in terms of output power, Q-factor, gain flatness and BER. Spacing among the WDM channels is 25 GHz in order to make system bandwidth efficient and scrutinized its effect on four wave mixing (FWM) in case of EDFA-EDFA, Raman-EDFA and SOA-EDFA. It is observed that SOA-EDFA is more and Raman-EDFA is less prone to FWM. Moreover, for distance 20 Km–140 Km, Raman-EDFA is optimal configuration for amplification and from 150 Km–200 Km, SOA-EDFA shows better performance. For prolonged link lengths such as beyond 200 Km, EDFA-EDFA is a right hybrid amplifier. In order to achieve maximum gain flatness in proposed architecture, EDFA-EDFA is recommended to use.

Heat release modelling of a range extender scroll engine

The proposed study aims to evaluate the feasibility of a range extender scroll engine by means of an analytical heat release rate analysis. This novel engine technology is comprising an upstream compressor and a downstream scroll expander which is mechanically connected and drives the compressor. Hence, the compression and expansion processes of the air-fuel mixture are decoupled which enables the possibility to apply higher expansion than compression ratios resulting in a scroll engine combustion process being similar to the Miller or Aktinson cycle. The scroll engine performance in terms of power output and thermal efficiency was accordingly evaluated for two compression ratios of 8.2:1 and 10.1:1 and six corresponding expansion ratios in the range of 8.2:1 to 17.8:1. It has been proven that high compression ratios are beneficial for the power output as more fuel can be introduced into the expander part. At a constant compression ratio, the power output increased for a rising expansion ratio but at the expense of a reduced power density. The evaluation revealed a peak value of 44.48kW at a compression ratio of 10.1:1 and an expansion ratio of 17.8:1. A more thorough expansion process due to the implementation of a Miller/Aktinson cycle resulted in a significantly increasing thermal efficiency for a rising ratio of expansion to compression ratio reaching a peak value

~3.5 $\mu$ m Er3+: ZBLAN Fiber Laser in Dual-End Pumping Regime

Mid-infrared (mid-IR) fiber laser sources at 3.5 μm have wide applications in spectroscopy, environmental monitoring, medicine, and defense countermeasures. In this work, we experimentally investigate a dual-end double wavelength pumped (i.e. both fiber ends pumped by 976 nm and 1973 nm, respectively) Er 3+ : ZBLAN fiber laser at 3.5 μm in detail. In the experiment, we carefully evaluate the lasing characteristics in terms of output power and scalability in contrast to the single-end pumping regime. The dual-end pumped Er 3+ : ZBLAN fiber laser yields a maximum output power of 1.72 W at the launched 1973 nm pump power of 8.39 W limited only by the available output power of the 1973 nm laser pump. The operation wavelength is experimentally found to be in a range from 3440 nm to 3620 nm depending on the pump power level. Lasing characteristics for Er 3+ : ZBLAN fibers with different lengths and doping concentrations and other cavity parameters are also investigated in this pumping regime to optimize the lasing performance.

A Threshold Voltage Model for Charge Trapping Effect of AlGaN/GaN HEMTs

In this paper, a threshold voltage model for charge trapping effect of AlGaN/GaN HEMTs is proposed. The quiescent bias stresses are considered for well modeling the current collapse critical points in pulsed I-V curves. Moreover, the low-frequency dispersions due to the charge trapping effect are well disposed by using the proposed model, which are validated by the scattering parameters (S-parameters). Also, a trapping related parameter α is proposed in the model, which can be conveniently used to describe the current collapse critical points offset due to the different acceptor energy levels of the dopants in GaN buffer. Different from our previous threshold voltage model, the proposed model in this paper can accurately model the dynamic threshold voltage shift due to the fast capture and slow emission processes. The verifications are carried out by comparing with the transient measured drain current. The proposed model is also implemented into a large-signal model for further verifications. The improved large-signal model with the threshold voltage shift model is verified by 0.25 μm process AlGaN/GaN HEMTs with pulsed I-V, S-parameters, power sweep and load-pull measurements. More accurate agreements between measured and modeled results have been achieved in terms of output power (Pout), gain and power added efficiency (PAE).

Statistical approach for the optimum selection of photovoltaic modules on a specific site

This paper introduces a probabilistic approach (PA) for the optimum selection of various photovoltaic (PV) modules manufactured by different suppliers to select the most suited module at a specific site location. This approach is based on fitting the probability distributions of the irradiance data measured at a specific hour of a typical day over a long term period (7 years). The goodness of fit test is employed to determine the best fitted probability density function which is then used in the calculation of the average output power and capacity factor (CF) of each module. Thus, the module with the highest average CF over the year is therefore considered as the best suited module for the given site location. The source files of solar irradiance database are approved by the Egyptian Meteorological Authority. Detailed modeling of the PV system characteristics using MATLAB/Simulink has been introduced, which shows complete stepping procedures and respective results. The combination of the detailed PV modeling along with the PA facilitates precise prediction of the best module in terms of output power under varying operating conditions and partial shading for the specified site.

Submillimeter Wave High Order Frequency Multiplier Based on Graphene

In this paper, a single stage millimeter/submillimeter wave frequency multiplier is presented. The desired frequency multiplication performance is obtained through the nonlinear excitation of high-order harmonic components in a graphene film, when it is illuminated with a low-frequency input signal. The graphene film is integrated into a microstrip structure on a polyimide substrate, which is subsequently embedded in a micromachined waveguide block. The design has been optimized to receive an input signal in the Ka frequency band, between 26.5 and 40 GHz, and to produce an output signal in the WR-3 frequency band, between 220 and 330 GHz. A complete prototype of the frequency multiplier module, including standard waveguide flanges for its interconnection, has been manufactured and experimentally characterized. The results in terms of output power in the WR-3 frequency band, for harmonic orders between 6 and 11, as well as for input power levels between 7 and 21 dBm, are presented.

Optimisation of a Quasi-Steady Model of a Free-Piston Stirling Engine

Energy from waste heat recovery is receiving considerable attention due to the demand for power systems that are less polluting. This has led to the investigation of external combustion engines such as the free-piston Stirling engine (FPSE) due to its ability to generate power from any source of heat and, especially, waste heat. However, there are still some limitations in the modelling, design and practical utilisation of this type of engine. Modelling of the FPSE has proved to be a difficult task due to the lack of mechanical linkages in its configuration, which poses problems for achieving stability. Also, a number of studies have been reported that attempt to optimise the output performance considering the characteristics of the engine configuration. In this study the optimisation of the second-order quasi-steady model of the gamma-type FPSE is carried out using the genetic algorithm (GA) to maximise the performance in terms of power output, and considering the design parameters of components such as piston and displacer damper, geometry of heat exchangers, and regenerator porosity. This present study shows that the GA optimisation of the RE-1000 FPSE design parameters improved its performance from work done and output power of 33.2 J and 996 W, respectively, with thermal efficiency of 23%, to 44.2 J and 1326 W with thermal efficiency of 27%.

Highly efficient power extraction in terahertz quantum cascade laser via a grating coupler

We demonstrate the highly efficient power extraction from terahertz quantum cascade laser (THz-QCL) via a grating coupler (GC). The GC, formed in the top metallization of a Fabry-Perot (FP) THz-QCL with a metal-metal (MM) waveguide, diffracts the THz wave into the free space when it oscillates between the two cleaved facets. The radiation loss can be tailored in a wide range by changing the structure of the GC. The asymmetric positioning of the GC enables near-unidirectional emission, the enlarged emission surface reduces the beam divergence, and the MM waveguide keeps the optical confinement factor near unity. Experimental results confirm that, when the operating frequency is near 2.7 THz, the laser with a GC shows superior performances than the conventional FP lasers in terms of output power and operation temperature.