Progress on large area n‐type silicon solar cells with front laser doping and a rear emitter

We report on the progress of imec's n‐type passivated emitter, rear totally diffused rear junction silicon solar cells. Selective laser doping has been introduced in the flow, allowing the implementation of a shallow diffused front surface field and a reduction of the recombination current in the contact area. Simplifications have been implemented towards a more industrial annealing sequence, by replacing expensive forming gas annealing steps with a belt furnace annealing. By applying these improvements, together with an advanced texturing process and emitter passivation by atomic layer deposition of Al₂O₃, 22.5% efficient cells (three busbars) have been realized on commercial 156 · 156 mm² Czochralski‐Si. This result has been independently confirmed by ISE CalLab. Copyright © 2016 John Wiley & Sons, Ltd.     

一种降低正交频分复用峰均功率比的方法

目前正交频分复用（OFDM）正得到越来越广泛的应用，但其主要缺点是有较高的峰均比（PAPR），虽然有许多降低OFDM信号的峰均比的方案，但是却大大增加了系统的复杂性，本文通过改进一种降低OFDM信号峰均功率的方法，很好地解决了复杂性和峰均比的降低的问题。     

High efficiency all‐GaAs solar cell

The reduction of surface recombination in GaAs solar cells is known to be a major concern for photovoltaic cells designers. A common technique used to reduce this effect is to cover the GaAs surface with a wide band gap window layer, therefore the creation of a heterojunction. To avoid a heterojunction with its inconveniences; interface surface states, poor photon absorption in addition to the technological exigencies, one can use an all‐GaAs solar cell. In this type of structure, a thin highly doped layer is created at the surface known as a front surface field (FSF). The main role of an FSF layer is to reduce the effect of front surface recombination and the enhancement of light‐generated free carriers' collection. This is achieved by the drastic reduction of the effective recombination at the emitter upper boundary. In this work, a simple analytical model is used to simulate the influence of the FSF layer on GaAs solar cell parameters; photocurrent, open circuit voltage and energy conversion efficiency. The effects of the FSF layer doping density and its thickness on the cell performance are discussed by using computed results. Copyright © 2010 John Wiley & Sons, Ltd.     

Design and Implementation of the Federation Load Simulator

The importance and necessity of emulating the federation load during simulating was analyzed firstly. Then, the special federation load emulation tool, federation load simulator （ FLS ）, was designed and implemented, by which all of the vital essential characteristics of a simulation could be tested, e. g. the amount of federates, the joint/resigned speed of federate, the amount of object instances, the registered/deleted speed of instance in one single program, etc.. The applications proved that FLS could provide a convenient, effective and adjustable simulation load testing environment during the procedure of run-time infrastructure（RTI） and interrelated tool federates researching, developing and performance testing. Furthermore, the FLS utilized all kinds of resources with high efficiency.     

安钢FSF电极智能预测建模及应用研究

交流电弧炉电极控制系统是一个多变量、非线性、参数时变、复杂强耦合系统,经典的控制策略难以获得优良的性能.为此从安钢FSF电极控制的实际应用出发,提出了1种变结构遗传Elman网络预测建模方法,其中改进的混和遗传算法用来对网络结构和权值及自反馈增益的同步动态寻优.并将基于BP算法的改进Elman网络和本文提出的变结构遗传Elman网络都应用于交流电弧炉的电极模型的辨识中,通过基于安钢现场数据的计算机仿真实验表明:变结构遗传Elman网络克服了因复杂的辨识对象造成的网络辨识结构复杂问题和采用BP算法带来的权值训练缺陷;并具有更好的动态性能,逼近速度快,精度更高等优点.最后,把建立的模型应用于电极控制系统的参数整定上,取得了良好的控制效果,为电极控制提供了理论指导.     

An engineered infilled frame: Behavior and calibration

The results of an experimental investigation on some engineered infilled frames with high ductility and adjustable strength are presented in this paper. To achieve an engineered infilled frame, an element is added to the infill, called Frictional Sliding Fuses (FSFs). The fuse acts before infill corner crushing and controls the infill so that it is not overloaded. Consequently, it increases the deformation capacity and decreases the strength deterioration. An FSF has a frictional nature, based on which the infill has more appropriate hysteresis cycles, leading to more structural energy damping during earthquakes. The results show that the engineered infilled frames have adjustable strength, as well as high ductility and damping.     

正交空时分组码在OFDM系统中的性能估计

在宽带OFDM系统中对正交空时分组码方案进行了研究,根据Almouti方案的译码原理给出了在正交空时分组码传输的频率选择性衰落信道条件下接收机输出瞬时信噪比的一般表达式,同时分两种情况进一步分析了其最小距离球界的符号差错性能。结果表明,在系统发送天线数、接收天线数及多径数目乘积较小的情形下,系统可以达到最大的分集增益。     

全冷料条件下烟道竖炉电弧炉的高效化生产

分析了在全冷料条件下100 t带指形托架的超高功率交流烟道竖炉电弧炉高效化生产的主要技术途径。将供电有功功率提高到55～60 MW,推迟2～5 min加入2批料,优化全冷料结构,造好泡沫渣,采用留钢留渣技术;同时,注意维护炉衬、脱磷、缩短热停工时间等问题,实现了100 t电弧炉冶炼周期44 min、吨钢冶炼电耗270 kW·h的生产实绩。     

安钢100t竖式电弧炉的系统优化与效果

介绍了安钢100t带指型托架超高功率竖式电弧炉(阿)系统优化方面的成功实践,及优化后取得的效果,为我国同类型电炉工程的改造发展提供借鉴。     

Opto‐electrical modelling and optimization study of a novel IBC c‐Si solar cell

Interdigitated back contact (IBC) crystalline silicon (c‐Si) solar cells are attracting a lot of attention because of their capability to reach world record conversion efficiency. Because of the relatively complex contact pattern, their design and optimization typically require advanced numerical simulation tools. In this work, a TCAD‐based simulation platform has been developed to account accurately and in detail the optical and passivation mechanisms of front texturization. Its validation has been carried out with respect to a novel homo‐junction IBC c‐Si solar cell based on ion implantation and epitaxial growth, comparing measured and simulated reflectance, transmittance, internal quantum efficiency, external quantum efficiency spectra, and current density–voltage characteristics. As a result of the calibration process, the opto‐electrical losses of the investigated device have been identified quantitatively and qualitatively. Then, an optimization study about the optimal front surface field (FSF) doping, front‐side texturing morphology, and rear side geometry has been performed. The proposed simulation platform can be potentially deployed to model other solar cell architectures than homo‐junction IBC devices (e.g., passivated emitter rear cell, passivated emitter rear locally diffused cell, hetero‐IBC cell). Simulation results show that a not‐smoothed pyramid‐textured front interface and an optimal FSF doping are mandatory to minimize both the optical and the recombination losses in the considered IBC cell and, consequently, to maximize the conversion efficiency. Similarly, it has been showed that recombination losses are affected more by the doping profile rather than the surface smoothing. Moreover, the performed investigation reveals that the optimal FSF doping is almost independent from the front texturing morphology and FSF passivation quality. According to this result, it has been demonstrated that an IBC cell featuring an optimal FSF doping does not exhibit a significant efficiency improvement when the FSF passivation quality strongly improves, proving that IBC cell designs based on low‐doped FSF require a very outstanding passivation quality to be competitive. Deploying an optimization algorithm, the adoption of an optimized rear side geometry can potentially lead to an efficiency improvement of about 1%_abs as compared with the reference IBC solar cell. Further, by improving both emitter and c‐Si bulk quality, a 22.84% efficient solar cell for 280‐μm thick c‐Si bulk was simulated. Copyright © 2017 John Wiley & Sons, Ltd.