A Hybrid Genetic Algorithm for Selective Harmonic Elimination PWM AC/AC Converter Control

This paper presents an optimal solution for eliminating pre-specified orders of harmonics from the output waveform of AC/AC converter. The main challenge of solving the associated nonlinear equations, which are transcendental in nature and therefore have multiple solutions, is the convergence and therefore an initial point selected considerably close to the exact solution is required. The paper discusses an efficient hybrid real coded genetic algorithm (HRCGA) that reduces significantly the computational burden resulting in a fast convergence. An objective function describing a measure of effectiveness of eliminating selected orders of harmonics, while controlling the fundamental is derived and a comparison of different operating points is reported. It is observed that the modulation index can reach unity value. The theoretical findings are verified through simulation results using the PSIM software package.     

溅渣护炉技术在临钢20t转炉上的应用

介绍了转炉溅渣护炉技术在临钢20t转炉上应用的基本情况，对应用中出现的主要技术问题提出了解决措施。     

中央空调领域的节能技术

论述了我国空调耗能的现状和空调节能的意义,从中央空调系统的选择、设备选型及系统运行管理三方面分析了影响空调节能的主要因素,简述了实现节能的几个方面,并着重讨论了设计中最普遍实施的冷却水系统节能的原理和方法。     

一种新型井间地震井下数据采集系统

介绍了一种用于井间地震的新型井下数据采集系统，它以数字信号处理单片机为核心，采用新型的高精度过采样∑－△Ａ／Ｄ转换器作为采集部件，首次将数字信号处理单片机放于下，进行数据采集的控制与实时数据处理，大大生意 化了采集电路并提高了采集数据的质量。     

PLC与变频器在自动给水系统中的应用

本文介绍的是自动变频调整速恒压供水系统。着重介绍了单个变频器对多个马达对象实现自动变频的系统硬件构成、软件编制以及整个模拟调节系统的实现。     

内冷——绝热氨合成塔内件和准等温型甲醇合成塔内件技术总结

介绍了内冷－绝热氨合成塔内件和准等温型甲醇合成塔内件的技术特性、操作要点及应用情况，并对存在的问题进行了分析。     

A novel charging/discharging balancing strategy for lithium battery pack based on mixed charging mode

Series‐connected lithium batteries can be charged in the pack‐charging mode, which is most widely used in the lithium battery application field. But the pack‐charging mode will lead to cell imbalance because of the difference in the electrochemical characteristics of the cells of series‐connected batteries. On the other hand, the cell‐charging mode can avoid the imbalance problem by charging each cell independently, but it will reduce the charging efficiency and increase the cost. In this paper, a novel balancing strategy is proposed with a mixed pack‐charging and cell‐charging mode to implement the balancing algorithm. The proposed strategy aims to solve the problem of charge/discharge imbalance with the simplest balancing algorithm with high balancing performance. There is no complex balancing behaviors during the charging process – as is the case with many other existing schemes – so the control algorithm can be greatly simplified. Because each cell can be fully charged and discharged with the proposed algorithm, it helps to make full use of the energy and capacity of each cell. The system stability and reliability of the proposed system, as well as its good performance, are verified through experiments. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

High‐power‐factor single‐switch AC to DC converter for LED lighting

In this paper, we report a novel single‐switch AC to DC step‐down converter suitable for light emitting diodes. The proposed topology has a buck and a buck–boost converter. The circuit is designed to operate in the discontinuous conduction mode in order to improve the power factor. In this topology, a part of the input power is connected to the load directly. This feature of the proposed topology increases the efficiency of power conversion, improves the input power factor, produces less voltage stress on intermediate stages, and reduces the output voltage in the absence of a step‐down transformer. The theoretical analysis, design procedure, and performance of the proposed converter are verified by simulation and experiment. A 36 V, 60 W prototype has been built to demonstrate the merits of this circuit. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

选择外延技术研制1.5μm DFB激光器和自对准模斑转换器集成器件

利用选择外延技术研制了1.5μm DFB激光器和自对准模斑转换器单片集成器件.激光器的上限制层与垂直方向上楔型波导的模斑转换器同时选择性生长 ,这样的方法不仅可以分别优化有源区和模斑转换器的材料,同时可以降低选择性生长对接结构的难度.所研制集成器件的阈值为4.4mA,在49.5mA下的输出功率为10.1mW,边模抑制比为33.2dB,垂直方向和水平方向上的远场发散角分别为9°和15°,1dB偏调容差分别为3.6μm和3.4μm.     

Support-induced promotional effects on the activity of automotive exhaust catalysts 1. The case of oxidation of light hydrocarbons (C2H4)

The kinetics of oxidation of a light hydrocarbon (C₂H₄) were studied on catalysts comprising of combinations of one of three metals, Pt, Pd or Rh supported on five different supports, that is, SiO₂, γ-Al₂O₃, ZrO₂ (8% Y₂O₃), TiO₂ or TiO₂ (W⁶⁺). Significant variation of turnover frequency with the carrier was observed, which cannot be explained by structure sensitivity considerations and is attributed to interactions between the metal crystallites and the carrier. The catalytic activity of these metal-support combinations was investigated over a wide range of partial pressures of ethylene and oxygen. In a separate set of experiments, the kinetics of C₂H₄ oxidation were also investigated on polycrystalline Rh films interfaced with ZrO₂ (8 mol% Y₂O₃) solid electrolyte in a galvanic cell of the type: C₂H₄, O₂, Rh/YSZ/Pt, air, during regular open-circuit conditions as well as under Non-Faradic Electrochemical Modification of Catalytic Activity (NEMCA), that is, closed-circuit conditions. Up to 100-fold increase in catalytic activity was observed by supplying O²⁻ ions to the catalyst surface via positive potential application to the catalyst. The observed kinetic behavior upon increasing catalyst potential parallels qualitatively the observed alteration of turnover frequency with variation of the support of the Rh crystallites.