Solar Array Output Research Articles

Online Learning-Based Surrogate Modeling of Stratospheric Airship Solar Array Output Power

The stratospheric airship is a type of aerostat that uses solar energy as its power source and can fly continuously for months or even years in near space. The rapid and accurate prediction of the output power of its solar array is the key to maintaining energy balance and extending flight time. This paper establishes an online learning model for predicting the output power of the solar array of stratospheric airships. The readings of radiometers arranged on the surface of the airship are used as features for training the model. The parameters of the model can be updated in real-time during the flight process without retraining the entire model. The effect of radiometer placement on the model accuracy was also analyzed. The results show that for the continuous flight of 40 days, the online learning model can achieve an accuracy of 88% after training with 10 days of flight data and the accuracy basically reaches its highest level after 20 days. In addition, placing the radiometers at the four corners of the array can achieve a higher prediction accuracy of 95%. The online model can also accurately identify and reflect the effect of module efficiency attenuation or damage and maintain high accuracy.

Performance analysis of winnowing dynamic reconfiguration in partially shaded solar photovoltaic system

To extract maximum power out of solar PV array when there is partial shadowing, a dynamic reconfiguration is required. Partial shade has significantly decreased output power, which lowers PV panel’s efficiency. Numerous strategies have been put out to prevent power loss reduction when partial shade occurs. Existing techniques have not been able to provide better power extraction at extremely low irradiation. The proposed winnowing technique for dynamic reconfiguration is appropriate to get rid of power loss due to mismatch under very low radiation. The suggested approach enhances the output power under partially shade condition in low-irradiation. Fifteen different shading scenarios and six reconfiguration switching patterns were investigated to confirm the proposed concept. The proposed winnowing technique increases the solar PV array output power up to 59.3% by effectively decreasing mismatch losses in the solar PV system.

Mismatch loss analysis of solar array output power on stratospheric airship during flight

Stratospheric airships are long-endurance aerostats and have broad applications. All of the energy required for their operation is obtained from solar radiation, which makes accurate calculation of the energy output from the solar array crucial to the design and flight planning of the airships. However, the status of each photovoltaic module in the solar array may differ due to the airship curvature, resulting in mismatch losses and lowered output power, which has not been widely studied. In this paper, an irradiation model and a thermal model are established based on the actual arrangement of the modules. The output power model is established considering the non-uniform radiation in the array. The mismatch losses of the array are analyzed under different flight conditions. The output power of the solar array is decreased by up to 31.6% compared to the ideal state. Moreover, the proportion of mismatch losses increases with latitude, but the maximum mismatch loss power occurs at mid-latitudes. Then, an array reconfiguration method is proposed based on the irradiance dispersion index and position dispersion index. The reconfigured array increases output power by 11.5% and can maintain energy balance in continuous flight. The results can be used to correct the overestimation of the output power during the airship design or to guide the configuration of the solar array.

Voltage-Fed single stage inverter for generating systems with Multi-Input inverter using Pulse Width Modulation

A voltage-fed single-stage multiple-input inverter is developed for hybrid wind/photovoltaic energy generating systems. In this research proposes a revolutionary multi-input inverter that simplifies and reduces the power system's cost. Inverter comprises the DC-DC converters and full-bridge ac inverters, which are buck/buck-boost. This study proposed a multi-input converter for hybrid photovoltaic and wind energy systems, with the basis and enhanced functionalities created by the scholars included in the design. A Novel Predictive Current Control Algorithm (NPCCA) is proposed for Hybrid a renewable energy source which depends on improved space-vector Pulse-Width-Modulation (PWM) to provide high-quality current and quick dynamic reaction to incorporate changes. Also discussed are the solar array and wind turbine output power characteristics. The Maximum Power Point-Tracking (MPPT) methodology is accomplished using the perturbation and observation methods to resist all non-linearities in the typical I-V curves. The proposed multi-input converters results in lower production costs for the converters since they use fewer semiconductors and take up less space. Soft-starting and circuit safety features are added for real-world uses. The simulation outcome of the NPCCA framework attained in terms of accuracy is 92% and efficiency is 92% when compared with the other existing approaches.

Perovskite Solar Cells and Thermoelectric Generator Hybrid Array Feeding a Synchronous Reluctance Motor for an Efficient Water Pumping System

Nowadays, water pumping systems based on photovoltaics as a source of electricity have widely increased. System cost and efficiency still require enhancement in order to spread their application. Perovskite solar cells (PSCs) are the most hopeful third-generation photovoltaic for replacing the silicon-based photovoltaic thanks to their high power conversion efficiency, reaching 25.8%; tunable band-gap; long diffusion length; low fabrication temperature; and low cost. In this work, for the first time, we proposed a high-power-density hybrid perovskite solar cell thermoelectric generator (TEG) array for feeding a synchronous reluctance motor (SynRM) driving a water pump for use in an irrigation system. A control technique was used to achieve two functions. The first function was driving the motor to obtain the maximum torque/ampere. The second was harvesting the maximum perovskite solar cell array output power on the basis of the maximum power point tracking (MPPT) algorithm using the perturbation and observation approach. Thus, the proposed hybrid perovskite solar cell–thermoelectric generator feeds the motor via an inverter without DC–DC converters or batteries. Accordingly, the short life problems and the high replacement cost are avoided. The proposed complete system was simulated via the MATLAB package. Moreover, a complete laboratory infrastructure was constructed for testing the proposed high-power-density hybrid perovskite solar cell–TEG array for the water pumping system. The results revealed that using the high-power-density hybrid perovskite solar cell–TEG array, both the motor’s output power and the pump’s flow rate were improved by 11% and 14%, respectively, compared to only using the perovskite solar cell array. Finally, both the simulation and experimental results proved the high-performance efficiency of the system in addition to showing its system complexity and cost reduction.

Grid-Responsive Smart Manufacturing: Can the Manufacturing Sector Help Incorporate Renewables?

Grid-responsive smart manufacturing has the potential to contribute greatly to the use of renewable energy sources in the manufacturing sector. Smart manufacturing includes the use of demand-side management to store energy in various forms as well as schedule operations so that power is used at optimal times. This work presents a case study of a mineral manufacturing site in the United States comparing different methods of smart manufacturing integrated with renewables. Using historical utility bills and various process models, the study seeks to quantify the savings and costs of various schemes in an overall effort to improve the economics of facility operation. The models compare solar arrays, battery storage, smart pumping schemes, and various combinations of those with process-integrated technology as viable ways to reduce energy costs. The study finds that a solar array by itself is prohibitively expensive for this facility. This is due to relatively high peak demand charges and the fact that the solar array's output does not align well with the facility's real-time power usage. The addition of a battery for load shifting helps the economics significantly, bringing the payback period down from 28.4 to 17.0 years. A key finding of this study, however, is that rather than battery storage, the facility can utilize existing process flexibility, namely pumps with variable frequency drives and built-in water storage capacity, to shift loads. The combination of solar with this novel smart pumping scheme brings the payback period for this investment down to 10.2 years. The smart pumping scheme by itself, however, has a near instant payback (0.13 years), demonstrating that enhanced automation can be used to leverage existing process equipment to operate as a “battery”, but at only a fraction of the cost of an actual battery.

An optimization approach for improving the solar array output power of stratospheric aerostat

Solar array is an integral part to the stratospheric aerostat energy system. The output power optimization of solar array needs to be conducted under the weight limitation for stratospheric aerostat long endurance mission. In the present paper, a rotatable system for optimizing the solar array output performance is proposed. Based on the theoretical model consisting of solar radiation model, energy model and optimization model, a MATLAB program is developed to calculate the thermal performance and output performance of solar array. The effects of latitude and flight date on the output performance are investigated in detail, the optimization results are obtained by comparing the rotatable solar array system with the traditional fixed solar array system. Studies have shown that the solar array output power is produced earlier with the rise of latitude and the output power peak value in summer solstice is greater than the values at other flight dates. The rotatable solar array system can comprehensively improve the solar array output power and the output power increment after optimization at high latitude is more than low latitude. The present work has valuable reference in solar array output power optimization and may be used to guide the design of the stratospheric aerostat energy system.

Optimal attitude control for solar array orientation

Abstract For low Earth orbit (LEO) satellites, solar panel is a firstly key device to convert the solar radiation into the electric power to supply the energy consume. However, the solar array is always suffering from the power degradation due to the harsh space environments. To meet the power balance in the end life of the spacecraft, attitude determination and control system (ADCS) plays an important role in the solar panel direction to change the solar energy input. Here, the solar cell performance parameters from an LEO satellite running on a dawn-dusk Sun synchronous orbit (SSO) are investigated. A yaw maneuver application is presented to satisfy the electric power supply (EPS) risk of the solar cell current decrease. Validated in the space operation, the results have shown that in the yaw mode, the EPS output is improved and the solar cell current is averagely enhanced more than 10% when the orbit incidence is 35°. The yaw maneuver is applied to the state of health (SOH) management with a better power supply. The solution can be widely and usefully taken into account to increase the solar array output for a near-Earth satellite in the risk of the power shortage.

Propose a MPPT Algorithm Based on Thevenin Equivalent Circuit for Improving Photovoltaic System Operation

Various maximum power point tracking methods (MPPT) for photovoltaic (PV) power systems have been considered and developed to maximize the delivered possible power. The output power of PV cells with nonlinear characteristics is affected by temperature, solar irradiation and load. In this paper, a modelized photovoltaic source is proposed, based on the Thevenin equivalent circuit at the beginning. A ordinarily employed solar system model is linearized into simple Thevenin source-resistance representation. Next, a control algorithm associated with the relationship between controller’s PWM duty cycle of the MPPT boost converter and solar array output power, namely proposed MPPT algorithm, is introduced. This proposed method is compared with an existing popular MPPT algorithm to confirm its superior performance by using the MATLAB/SIMULINK simulation. Finally, a 50W DC-DC boost converter prototype is implemented and tested to verify the feasibility of the proposed control scheme.

Investigation on the effects of shadow on output performance and thermal characteristic of the solar array on stratospheric aerostat

The attenuation of solar direct radiation passing through stratospheric balloon has great impacts on solar array output performance and thermal characteristic. The thermal characteristic of solar array with balloon shadows taken into account is rare. In this study, we established a theoretical model which consists of solar radiation model, shadow model, thermal model and energy output power model to evaluate their power performance and thermal characteristic under shaded conditions. Based on the theoretical model, a MATLAB simulation program was developed. For model validation, solar array performances are simulated and compared with literature results. Comparing the results of calculation whether balloon shadow is considered or not, the balloon shadow greatly affects the output power and temperature of solar array. Effects of the date, latitude, rope length on the output performance and thermal characteristic of solar array were investigated in detail. The results show that the balloon shadow covering the solar array effectively reduces the direct solar radiation received by the solar array, which has contributed to the decline of the output power and average temperature of the solar array. In addition, it is found that choosing the appropriate rope length can effectively reduce the detrimental effects of the balloon shadow.

Optimum attitude planning of near-space solar powered airship

The attitude of Near-space airship including yaw, roll and pitch angle is important to the output performance of airship solar array. The yaw angle of airship can be controlled without affecting airship mission execution in the quasi-zero wind layer of near-space. This paper aims to improve solar energy system of near-space airship by optimizing airship yaw angle. Based on the solar radiation model and solar array energy model, a MATLAB program is established to calculate the output power. For model validation, solar radiation and output power are simulated and compared with experimental results. The optimum yaw angle for a whole year is obtained with optimization model based on genetic algorithm. The effect of airship shape parameters including the slenderness ratio and the ratio of forebody length to total length (L1/L) is elaborated. The results show that the effect of yaw angle on output power is greater at higher latitude than that at lower latitude and the solar array output energy can be remarkable increased after adjusting yaw angle of airship according to the optimization result. Although the optimal yaw angle is different with the change of working date and latitude, the optimum values mainly lie in 0° and 180°. Moreover, the optimal yaw angle is barely changed, when the slenderness ratio and L1/L of airship are greater than 0.3 and 0.25, respectively. The result has great valuable engineering reference in attitude planning of near-space airship and other aerospace vehicle for energy improvement.

Five‐Year Results From the Engineering Radiation Monitor and Solar Cell Monitor on the VanAllen Probes Mission

AbstractThe Engineering Radiation Monitor measures dose, dose rate, and charging currents on the Van Allen Probes mission to study the dynamics of Earth's Van Allen radiation belts. Over 5 years, results from this monitor show a variation in dose rates with time, a correlation between the dosimeter and charging current data, and a comparison of cumulative dose to prelaunch modeling. Solar cell degradation monitor patches track the decrease in solar array output as displacement damage accumulates. The Solar Cell Monitor shows ~33% cumulative degradation in maximum power after 5.1 years of the mission. The desire to extend the mission to ~2,500 days from 800 days created increased requirements for the ionizing radiation hardness of spacecraft and science instrument electronics. We describe the investigations that insured compliance with these enhanced requirements.

Control Strategy of Maximum Output of Solar Array

This paper first describes the working principle of solar cells, solar cell work to analyze the equivalent circuit and simulation model. Secondly, the two traditional maximum power point tracking control algorithms are analyzed and compared, and their respective advantages and disadvantages are proposed. Incremental Conductance and P&O.

Modelling and Application of Output Current of the Solar Array for Satellite in Sun Synchronous Orbit

The output current of the solar array for satellite in sun synchronous orbit is a critical parameter for performance in-orbit analyzing. In order to analysis the rules of the solar array output current accurately, some influential factors, such as the incidence angle of the sun, the temperature of the solar array, the earth-sun distance factor and the fixed offset angle to the sun of solar wing, are comprehensively researched. Then a model of output current is established. Results in-orbit show that the model has high accuracy, which can provide a reference for optimization design of satellite solar array.

A thermal model to investigate the power output of solar array for stratospheric balloons in real environment

It is very important to solve the energy problem of stratospheric balloon to operate at high altitude for extended durations. Solar energy is the ideal power choice for long endurance stratospheric balloon. This study outlines a simplified numerical model validated using field data covers the thermal model of solar array that is not affected by balloon inside environment as airship does, the solar radiation model, the power output model. The predicted and measured solar array temperature and output power values yield correspondence with deviations below 2.16%, 6.6%, respectively. Based on this numerical model, computer program has been developed and simulated. The simulation was applied to a stratospheric balloon flight in one of the cities of Turkey’s atmospheric conditions including real wind data. The output performance of solar array with and without thermal effect is reported. Furthermore, transmissivity of external encapsulation, wind speed on thermal performance and power output of solar array is discussed in detail. The results would be helpful for the design, operation of stratospheric balloon solar power system.

Transmittance optimization of solar array encapsulant for high-altitude airship

Abstract The efficiency of solar cell is a critical problem to the energy management of high-altitude airship. Excessive temperature and solar radiation intensity of solar cell will reduce the cell efficiency. The main purpose of this study is to increase the energy output of solar array through optimizing transmittance of solar array encapsulant. The thermal and heat transfer models of solar array were considered during the investigation of the effect of transmittance on output performance of solar array. And the optimization model of transmittance is presented to obtain the optimum transmittance in different working conditions for the first time. The feasibility of the numerical model is verified by comparison with experimental data of the temperature of solar array during a day. The results indicate that the output performance of solar array is variable under different transmittances and the optimum transmittance of solar array is changing with the working latitude and date. The simulation results show that the maximum increase of output energy can reach up to 0.5 MJ on summer solstice. The optimization study provides both theoretical and practical support for choosing optimal encapsulant materials in the preparation stage of high-altitude airship.

Rapid Prototyping of a Low-Cost Solar Array Simulator Using an Off-the-Shelf DC Power Supply

A method of rapid prototyping of a solar array simulator, based on low cost, off-the-shelf components is proposed in the paper. A commercial constant output voltage switching power supply is utilized as a power stage. It is shown that it is possible to gain control over output voltage of such a device by injecting variable analog voltage into the voltage feedback loop of the supply. As a result, by sensing the power supply output current and varying the injected voltage it is possible to change the output voltage according to a predefined relation and hence any static I–V curve may be emulated by the device. For simulating a solar array output characteristics, the desired I–V curve may be either digitized from a manufacturer provided datasheet, obtained experimentally or estimated from three basic current–voltage pairs (open circuit, short circuit, and maximum power points) using a dedicated algorithm. In order to demonstrate the proposed method, a prototype was designed and built based on available low-cost commercial components. Dynamic characteristics of the prototype were experimentally evaluated and three static I–V curves of a commercial solar panel were simulated. The resulting I–V output characteristics were shown to closely resemble datasheet I–V curves.

Output Power Prediction Method of GEO Satellite Solar Array Based-on the Modified Equivalent Circuit Model

It proposed a single-exponential equivalent circuit model in order to predict the output power of geostationary satellite solar array. The key factors of the model are the short-circuit current ( ) , the open-circuit voltage( ) , the maximum power point current ( ) and the maximum power point voltage( ), which are used with corresponding coefficient to calculate the updated four parameters and I-V characteristics equation based on the new light intensity and temperature. Then, the power of various light intensity and temperature are calculated according to the provided voltage data, and a modified model is achieved by considering the attenuation factor. At last, this paper presents two experiments of the short-term and long-term solar array output power prediction. The comparison results of the predicted power and real power illustrate the prediction accuracy of 85%. Therefore, this power prediction model is sufficient for most engineering applications.

Early Results From the Engineering Radiation Monitor (ERM) and Solar Cell Monitor on the Van Allen Probes Mission

The Engineering Radiation Monitor (ERM) measures dose, dose rate and charging currents on the Van Allen Probes mission to study the dynamics of earth's Van Allen radiation belts. Early results from this monitor show a variation in dose rates with time, a correlation between the dosimeter and charging current data, a map of charging current versus orbit altitude and a comparison of cumulative dose to pre-launch modeling after 260 days. Solar cell degradation monitor patches track the decrease in solar array output as displacement damage accumulates.

The Analysis of Abnormal Phenomena of GEO Satellites Solar Array

Satellites solar array provides sustainable and reliable energy for satellite by changing the solar energy into electrical energy in order to ensure the normal working of the satellite. The working status of solar array is directly related to the satellites normal running in orbit. The thesis summarized the normal trend of the GEO satellites solar array output power, through comparing the real output power of a certain satellites solar array with the normal trend, and detected four abnormal phenomena of solar array output power. Then the thesis analyzed the reasons, and made related suggestions.