Second international spectroradiometer intercomparison: results and impact on PV device calibration

This paper describes the results of an intercomparison of spectroradiometers for measuring global normal incidence and direct normal incidence spectral irradiance in the visible and in the near infrared, together with an assessment of the impact these results may have on the calibration of the short circuit current (I_sc) of triple‐junction photovoltaic devices and on the relevant spectral mismatch calculation. The intercomparison was conducted by six European scientific laboratories and a Japanese industrial partner. Seven spectroradiometer systems, for a total of 13 different instruments/channels using two different technologies and made by four different manufacturers were involved. This group of systems represents a good cross section of the instrumentation for solar spectrum measurements available to date. The instruments were calibrated by each partner prior to the intercomparison following their usual procedure and traceability route in order to verify the entire measurement and traceability chain. The difference in measured spectral irradiance showed to have an impact on the calibration of a set of Iso‐Type cells varying from ±2% to ±14% for middle and bottom cell, respectively. Copyright © 2014 John Wiley & Sons, Ltd.     

绝缘栅双极晶体管基础

IGBT结构及工作原理 IGBT是强电流、高压应用和快速终端设备用垂直功率MOSFET的自然进化。由于实现一个较高的击穿电压BV为oss需要一个源漏通道,而这个通道却具有很高的电阻率,因而造成功率MOSFET具有Ros(on)数值高的特征,IGBT消除了现有功率MOSFET的这些     

Changes of solar cell parameters during damp‐heat exposure

The electrical ageing of photovoltaic modules during extended damp‐heat tests at different stress levels is investigated for three types of crystalline silicon photovoltaic modules with different backsheets, encapsulants and cell types. Deploying different stress levels allows determination of an equivalent stress dose function, which is a first step towards a lifetime prediction of devices. The derived humidity dose is used to characterise the degradation of power as well as that of the solar cell's equivalent circuit parameters calculated from measured current–voltage characteristics. An application of this to the samples demonstrates different modes in the degradation and thus enables better understanding of the module's underlying ageing mechanisms. The analysis of changes in the solar cell equivalent circuit parameters identified the primary contributors to the power degradation and distinguished the potential ageing mechanism for each types of module investigated in this paper. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd.     

Human factor: the competitive advantage driver of the EU’s logistics sector

This article aims to test the weight that main sub-components of the global competitiveness index might have on the logistics performance index. We deploy a novel technique based on three newly particularised clusters (‘infrastructure’, ‘institutions’ and ‘human factor’) to look into whether such clusters are related to efficiency in the 28 European Union’s countries. It is manifest that the human factor is far more important for improving the logistics performance index than infrastructure and institutions. It follows that in this new domain of analysis, all initiatives to prioritise investment on the human factor are appropriate means of stimulating innovation and economic outlook, perceived that the logistics sector accounts for an average of 10% of the European Union’s GDP.