Multichip module photovoltaic miniarrays

In this work a novel concept of photovoltaic mini array assembly is described based on a flip-chip multichip module technology. A number of arrays composed of 15 series-connected 2 mm² c-Si photovoltaic cells have been fabricated, achieving a packaging density of 40 cells/cm². Measurements of the dark I-V characteristic confirmed that the resistive losses of the approach are small and do not degrade the electrical characteristics of the array. Nearly 0.5 mW/cm ² delivered density power, and 7 V in open circuit conditions were typically measured under normalized solar spectrum (AM1.5 100 mW/cm ²), and around 6.3 mW/cm² and 8.5 V using a 150 W commercial lamp placed at 5 cm distance from the panel     

Validation of energy prediction method for a concentrator photovoltaic module in Toyohashi Japan

III–V concentrator photovoltaic systems attain high efficiency through the use of series connected multi‐junction solar cells. As these solar cells absorb over distinct bands over the solar spectrum, they have a more complex response to real illumination conditions than conventional silicon solar cells. Estimates for annual energy yield made assuming fixed reference spectra can vary by up to 15% depending on the assumptions made. Using a detailed computer simulation, the behaviour of a 20‐cell InGaP/In_0.01GaAs/Ge multi‐junction concentrator system was simulated in 5‐min intervals over an entire year, accounting for changes in direct normal irradiance, humidity, temperature and aerosol optical depth. The simulation was compared with concentrator system monitoring data taken over the same period and excellent agreement (within 2%) in the annual energy yield was obtained. Air mass, aerosol optical depth and precipitable water have been identified as atmospheric parameters with the largest impact on system efficiency. Copyright © 2012 John Wiley & Sons, Ltd.     

20% efficient photovoltaic module

Describes the first 20% efficient flat-plate photovoltaic module ever reported. The 743-cm² module is based on large-area PERL silicon cells (passivated emitter rear locally diffused) of average unencapsulated efficiency of 21.3%, giving an independently confirmed module energy conversion efficiency of 20.6% under standard test conditions. The module also shows a very low temperature coefficient of performance increasing its performance advantage over standard silicon modules at increased temperature. Also reported is an independently confirmed efficiency of 21.6% for a 46 cm² cell of the type used in the module, the highest efficiency ever reported for a cell of this size     

储能技术在光伏并网发电系统中的应用分析

本文在根据光伏并网发电系统的特点与影响,针对储能技术的应用进行分析研究。     

From costs to prices: economic analysis of photovoltaic energy and services

A global economic analysis methodology is proposed in order to simplify the cost and the profitability assessment of energy and services delivered by photovoltaic (PV) systems. As examples, equations and graphic tools derived from this methodology give directly the overall discounted cost (ODC) of electricity delivered by grid-connected PV power plants and the ODC of water delivered by a stand-alone PV pumping system. The main criteria used for profitability analysis of PV projects are reviewed: net present value, internal rate of return and profitability index (PI). A simple method with associated equations and graphic tools is presented in order to assess the profitability of PV projects from their PI. Examples of profitability analysis of present and future grid-connected PV power plants built and operated by an independent power producer are presented and discussed, together with examples of stand-alone PV water pumping systems operated by the local community in developing countries. In both cases, equations and specific graphic tools are presented. Specific graphs can be used with different monetary units, different sizes and different investment costs of PV projects. © 1998 John Wiley & Sons, Ltd.     

Effects of shadowing on photovoltaic module performance

A procedure of simulation and modelling PV modules' performance, working partially shadowed, is presented. Several shadow rates have been tested on a single cell forming part of a PV module having 36 solar cells serially connected, and the influence of shadow rate in most of the important PV module characteristic parameters has been evaluated.The correlation between PV module output lowering due to shadowing and the variation of resistive losses is also reported. Copyright © 2007 John Wiley & Sons, Ltd.     

应用于聚光光伏模组的全反射式二次聚光器的设计与性能分析

当前聚光光伏系统存在很多问题,比如跟踪器的跟踪精度偏低、聚焦光斑强度分布不均匀、聚焦光斑的形状跟太阳电池不匹配等,二次聚光器可以解决这些问题,从而提高高倍聚光光伏系统的光电转换效率.对高倍聚光光伏系统中的菲涅耳透镜和二次聚光器的聚光原理进行了简要分析,重点对全反射式二次聚光器进行了二维聚光的理论分析,并配合非成像光学的...     

Artificial neural network‐based photovoltaic module temperature estimation for tropical climate of Malaysia and its impact on photovoltaic system energy yield

This article presents an artificial neural network (ANN)‐based approach for predicting photovoltaic (PV) module temperature using meteorological variables. The proposed approach utilizes actual hourly records of various meteorological parameters, such as ambient temperature T_a, solar irradiation G, relative humidity RH, and wind speed Ws as input variables. The hourly meteorological data were collected over 9 months in the year 2009 from a 92‐kWp installed PV system in Selangor, Malaysia. The data were divided into two sets: training data, which are a set of 1849 (April–October) hourly data, and 578 (November–December) hourly records of working as test data. Four ANN models have been developed by using different combination of meteorological parameters as inputs, and, for each model, the output is the PV module temperature T_m. It was found that the model using all parameters, including RH and Ws as inputs, gave the most accurate results with correlation coefficient (r) 95.9%, and 0.41, 0.1, and 4.5% for MBE, RMSE, and MPE, respectively. To show the superiority and applicability of the developed ANN model, results from the proposed ANN model have been compared with the conventional model adopted by Malaysia Energy Center and another mathematical model based on regression. With the model's simplicity, the proposed approach can be used as an effective tool for predicting the PV module temperature, for any type of PV systems, in remote or rural locations with no direct measurement equipments. The developed model also will be very useful in studying PV system performance and estimating its energy output. Copyright © 2013 John Wiley & Sons, Ltd.     

Compact spectrum splitting photovoltaic module with high efficiency

We have designed, fabricated, and tested a small, integrated photovoltaic module comprised of two separately‐contacted, high efficiency, multijunction solar cells and non‐imaging optics that both concentrate and spectrally split the incoming light. This hybrid design allows us to individually optimize the tandem cells and optical elements. The system has a measured module efficiency, including optical and packaging losses but not power combination losses, of 38.5 ± 1.9% under the AM1.5 direct terrestrial spectrum. The internal optics concentrate the light by a factor of approximately 20. We find excellent agreement between the modeled and measured performance. This is the highest confirmed conversion efficiency demonstrated for a photovoltaic module. Copyright © 2010 John Wiley & Sons, Ltd.     

Predetermined static configurations of a partially shaded photovoltaic module

Partial shading causes power loss in a photovoltaic module by inducing a power mismatch within the module. This power loss can be significant in building‐applied and building‐integrated photovoltaic installations. Given the often repetitive nature of shade profiles in such applications, we propose to employ non‐reconfigurable or static configurations. We use our simulation tool to precompute static configurations, apply shading scenarios, such as a chimney or tree shade, and make a comparison between the energy yields of different static configurations, which includes that of a conventional module. We then identify the configuration characteristics that consistently yield a higher energy. Copyright © 2016 John Wiley & Sons, Ltd.     

Electronic controlled device for the analysis and design of photovoltaic systems

The characterization and design of photovoltaic systems is a difficult issue due to the variable operation atmospheric conditions. With this aim, simulators and measurement equipments have been proposed. However, most of them do not deal with real atmospheric conditions. This letter proposes an electronic device that first measures the real evolution of the I-V characteristic curves of photovoltaic modules and generators, and then physically emulates in real time these curves to test photovoltaic inverters. The device consists of a dc-dc converter, a microcontroller and a data storage unit. The two operation modes (emulation and measurement) are digitally driven by the microcontroller. The converter current is controlled by means of a variable-hysteresis control loop, whose reference is provided by the microcontroller. In addition, a digital voltage control loop is designed to find out the complete characteristic curves of the photovoltaic generators. A 15-kW prototype is designed and built that can measure three times per second the characteristic curves of up to seven generators and then emulate their electrical behavior to test photovoltaic inverters. With the proposed device, the optimal configuration and performance of photovoltaic modules and generators, as well as the operation of photovoltaic inverters can be thoroughly analyzed under real atmospheric conditions.     

Residential photovoltaic energy storage system

This paper introduces a residential photovoltaic (PV) energy storage system, in which the PV power is controlled by a DC-DC power converter and transferred to a small battery energy storage system (BESS). For managing the power, a pattern of daily operation considering the load characteristic of the homeowner, the generation characteristic of the PV power, and the power-leveling demand of the electric utility is prescribed. The system looks up the pattern to select the operation mode, so that powers from the PV array, the batteries and the utility are utilized in a cost-effective manner. As for the control of the system, a novel control technique for the maximum power-point tracking (MPPT) of the PV array is proposed, in which the state-averaged model of the DC-DC power converter, including the dynamic model of the PV array, is derived. Accordingly, a high-performance discrete MPPT controller that tracks the maximum power point with zero-slope regulation and current-mode control is presented. With proposed arrangements on the control of the BESS and the current-to-power scaling factor setting, the DC-DC power converter is capable of combining with the BESS for performing the functions of power conditioning and active power filtering. An experimental 600 W system is implemented, and some simulation and experimental results are provided to demonstrate the effectiveness of the proposed system     

Implementation of cost-effective wireless photovoltaic monitoring module at panel level

Given the rapidly increasing market penetration of photovoltaic (PV) systems in many fields, including construction and housing, the effective maintenance of PV systems through remote monitoring at the panel level has attracted attention to quickly detect faults that cause reductions in yearly PV energy production, and which can reduce the whole-life cost. A key point of PV monitoring at the panel level is cost-effectiveness, as the installation of the massive PV panels that comprise PV systems is showing rapid growth in the market. This paper proposes an implementation method that involves the use of a panel-level wireless PV monitoring module (WPMM), and which assesses the cost-effectiveness of this approach. To maximize the cost-effectiveness, the designed WPMM uses a voltage-divider scheme for voltage metering and a shunt-resistor scheme for current metering. In addition, the proposed method offsets the effect of element errors by extracting calibration parameters. Furthermore, a design method is presented for portable and user-friendly PV monitoring, and demonstration results using a commercial 30-kW PV system are described.     

Control of particulate and gas emissions in photovoltaic module manufacture

Emissions of toxic gases and particulates from photovoltaic module R&D and manufacturing facilities may need treatment to meet current or anticipated regulations. In this study currently available pollution-control options (e.g. filters, scrubbers, adsorption columns, combustion devices) are reviewed for their suitability to treat emissions (e.g. HCl, HF, Cl₂, H₂Se, SiH₂, SiH₂Cl₂, AsH₃, PH₃, Cd and As compounds) from photovoltaic cell laboratories and production facilities. For small emission flow rates (e.g. > 100 l min⁻⁻¹) and small to moderate particulate loads (e.g. <2 mg l⁻⁻¹), on-line filters can economically collect fumes and other particulates generated in the deposition chambers, whereas adsorption columns can very effectively treat toxic hydrates (e.g. AsH₃, PH₃, H₂Se) at concentrations up to 1% (up to 10% for very small flow rates, e.g. <11 min⁻⁻¹). For large emission flow rates, (e.g. > 100 1 min⁻⁻¹), very low concentrations of hydrates can still be treated effectively with adsorption. Combined control of particulates and hydrates can be achieved by a bag-house followed by a multistage scrubber; when the concentration of hydrates is relatively high, a thermal oxidation unit should precede the bag-house scrubber for effective control. Finally, multicomponent mixtures can be treated either by wet scrubbing or combustion, depending on the mixture composition.     

CPLD在基于PCI总线的功率模块设计中的应用

针对机电一体化开发平台中微处理器模块与功率模块通过PCI总线实现通信．介绍了一种基于复杂可编程逻辑器件（CPLD）的驱动直流电机的脉宽调制（PWM）电路设计。该电路设计可产生三路占空比与频率可调的PWM信号,实现PWM控制直流电机。     

Assessing the reliability and degradation of photovoltaic module performance parameters

Photovoltaic (PV) modules are renowned for their reliability. However, some modules degrade or even fail when operating outdoors for extended periods. To reduce the degradation, and the number of failures, extensive research is needed on the performance of PV modules. The aim of this study was to establish a photovoltaic degradation and failure assessment procedure. This procedure should assess all parameters of PV modules to completely analyze any observed degradation or failure. In this paper some degradation modes of PV modules are discussed and a procedure used to assess these degradation modes is then presented. Results obtained by subjecting Copper Indium Diselenide (CIS), single and triple junction amorphous silicon (a-Si and a-SiGe), Edge-defined Film-fed Growth (EFG) silicon and mono-crystalline silicon (mono-Si) modules to the assessment procedure are presented and discussed. Results obtained indicate that the thin-film modules degrade by up to 50% in performance after an initial outdoor exposure of 130 kWh/m/sup 2/. Visual inspection revealed that both crystalline modules had cracked cells. The mismatch due to the cracked cell in the EFG-Si module, however, was limited by the interconnect busbars. This paper accentuates the importance of characterizing all module performance parameters in order to analyze observed degradation and failure modes.     

电源模块的电磁干扰设计

电源设计中即使是普通的直流到直流开关转换器的设计都会出现一系列问题,尤其在高功率电源设计中更是如此。除功能性考虑以外,工程师必须保证设计的鲁棒性,以符合成本目标要求以及热性能和空间限制,当然同时还要保证设计的进度。