水泥生产中预加水成球微机控制系统

叙述水泥生产中以ＳＴＤ８０９８微机系统为核心组成的生料预加水成球控制系统的构成、工作原理及软件结构。该系统目前已在云阳钢铁厂水泥分厂投入使用，效果良好，成球合格率在９０％以上。     

一种改进的异步电动机直接转矩控制方法

针对传统异步电动机直接转矩控制方法转矩及磁链脉动大、开关频率不固定的缺点,提出了一种改进的异步电动机空间矢量调制直接转矩控制方法。该方法通过转矩角闭环控制实现定子磁链幅值和相角的解耦,从而获得参考电压空间矢量,实现对磁链误差和转矩误差的控制。仿真结果表明,该方法有效地克服了传统直接转矩控制方法的缺陷,获得了良好的动态响应性能。     

一种用于电机重载起动的变频控制方法

针对当前实现电动机重载起动方案所存在的诸多问题,研究了一种基于80C196KC DSP为控制核心的交-交变频控制的实现方法。该方法具有起动电流小、起动转矩大、起动平滑、运行稳定、控制效果好的特点。本文对系统主电路及控制部分进行详尽论述,对实验及仿真结果进行了分析。     

基于PLC的感应淬火数控系统设计

简要介绍了淬火机床的工作原理,利用PLC实现了感应淬火机床专用数控系统,并给出了系统的硬件设计,同时详细介绍了位置控制、手动操作、脉冲补偿、参数设置与显示、急停等程序设计.     

Experimental study of GaN based blue light emitting diodes with a thin AlInN layer in front of the electron blocking layer

The GaN based blue light emitting diodes (LEDs) with a thin AlInN layer inserted in front of the electron blocking layer (EBL) are experimentally studied. It is found that inserting a thin EBL can improve the light output power and reduce the efficiency droop compared with the conventional AlGaN counterparts. Based on numerical simulation and analysis, the improvement on the electrical and optical characteristics is mainly attributed to the reduction of the electron leakage current, which increases the concentration of carriers in the quantum well (QW) when the thin AlInN layer is used.     

Effects of Mg-doping concentration on the characteristics of InGaN based solar cells

A major challenge in GaN based solar cell design is the lack of holes compared with electrons in the multiple quantum wells (MQWs). We find that GaN based MQW photovoltaic devices with five different Mg-doping concentrations of 0 cm-3, 5×1017 cm-3, 2×1018 cm-3, 4×1018 cm-3 and 7×1018 cm-3 in GaN barriers can lead to different hole concentrations in quantum wells (QWs). However, when the Mg-doping concentration is over 1×1018 cm-3, the crystal quality degrades, which results in the reduction of the external quantum efficiency (EQE), short circuit current density and open circuit voltage. As a result, the sample with a slight Mg-doping concentration of 5×1017 cm-3 exhibits the highest conversion efficiency.     

齿轮感应淬火机床数控系统设计

为了提高齿轮感应淬火机床的加工精度和效率,采用触摸屏和PLC构成了机床数控系统,详细介绍了数控系统的硬件构成和软件设计过程.该数控系统在齿轮感应淬火机床上应用后,效果良好.     

双工位立式通用淬火机床设计

介绍了双工位立式通用淬火机床结构与特点,机床数控系统由工控PLC、触摸屏及伺服控制系统组成,两个工位共享加热电源,也可以共享淬火文件,淬火参数表格化输入.     

变压器移动式通用感应淬火机床

淬火变压器滑板拖架移动采用滚珠丝杠传动,伺服电机驱动,移动速度可根据工艺要求任意设定.零件旋转采用变频调速控制,上顶尖高度可电动调整,以适应淬火零件长度的变化.采用三菱PLC+触摸屏组成的数控系统实现淬火工艺程序自动控制,淬火工艺程序可键盘输入、存储和修改.机床具有连续淬火、同时淬火、分段连续淬火、分段同时淬火等功能,主要用于轧辊及各种重型轴类零件表面感应淬火.