液压动力转向车辆的蛇行试验与仿真

汽车的操纵稳定性决定了汽车的操控性、行驶安全性和抗外界干扰能力,而转向系统与汽车操纵稳定性关系最为密切。为研究液压动力转向车辆的操纵稳定性,利用Matlab/Simulink建立了液压动力转向系统以及整车三自由度状态方程的仿真模型,在使用试验数据验证仿真模型正确性的基础上,对模型进行了蛇行试验的操纵稳定性仿真,分析了液压动力转向系统的系统结构参数对蛇行试验的影响,仿真结果的分析为动力转向系统的设计和提高车辆操纵稳定性提供了依据。     

Multivariable optimization of thermal cracking severity

The changing market forces are driving olefin producers to operate their steam crackers at high operating rates and optimum production performances. These require the use of an optimizer for assessment of viable operational strategies. Most of the optimizers currently employed in this area make use of the coil outlet temperature to determine an improved severity. In rare cases only, a multivariable optimization is performed on the furnace operational conditions. This kind of optimization is implemented in PyroFur for optimizing both the furnace operation and the reaction severity using a set of first-principles mathematical models in which the coil outlet temperature, the total feed flow rate and the steam/hydrocarbon ratio are altered. The suggested procedure was applied as a case study for a typical liquid furnace. Typical improvements obtained from the optimizing control strategy proposed in this article include about 1.4% increased profitability per year per furnace. Effect of a change in the prices or the feed composition is also presented.     

基于电荷泵功率因数校正技术的小功率高压钠灯用电子镇流器

本文研究了输入电流连续型电荷泵功率因数校正(CIC-CPPFC)技术在电子镇流器中的应用,采用CIC-CPPEC技术实现的电子镇流器,与传统的双功率级电子镇流器相比,结构简单、电压应力低、功率密度高、成本低。本文成功设计出了一台适合50W高压钠灯用电子镇流器。实验表明,这种单功率级电子镇流器不仅能实现高压钠灯变频软启动,而且能保证在输入电网电压大范围变化时实现恒功率运行。它具有完善的多重保护功能,功率因数大于0.98,THD值小于15%。