电子科学与技术英文摘要的撰写.docVIP

PAGE  PAGE 5 英文摘要的撰写 例一： Research on the Technology of the Neutral-point Voltage Balance and Dual-loop Control Scheme for Three-level PWM Rectifier ABSTRACT: A mathematical model of the three-level PWM rectifier is set up. Compared with the model of DC motor, some similarities are established. Based on the state feedback decoupling, the dual close-loop control of DC motor is applied to three-level PWM rectifier. As a result, the three-level rectifier has favorable dynamic and steady state performance, sinusoidal input current and unity power factor. Besides, a method is proposed to control the neutral-point voltage charge unbalance, which is an inherent problem of three-level inverter. The redundant positive small vectors and negative small vectors are selected according to the direction information of input current of each phase as well as the ripple of neutral-point voltage. Finally, experimental results verify the feasibility and validity of dual-loop control system and neutral-point voltage control method. KEY WORDS: three-level; PWM rectifier; dual-loop control; unity power factor; neutral-point voltage balance 三电平PWM整流器双环控制技术及中点电压平衡控制技术的研究 摘要：该文在建立了三电平PWM整流器系统数学模型的基础上，比较了三电平PWM整流器模型与直流电机模型的相似性，基于对控制对象的状态反馈解耦，提出把直流电机的双闭环控制应用于三电平PWM 整流器中，使三电平PWM整流器具有良好的动态性能和稳态性能，并且保证输入电流波形正弦性好，实现了单位功率因数。同时，针对三电平PWM 整流器所固有的直流侧电容中点电压平衡问题，提出根据每相输入电流方向和中点电压波动方向来优化选取冗余的正小矢量和负小矢量，实现中点电压平衡控制的方法。最后通过实验验证了双环控制器和控制中点电压方法的可行性和有效性。 关键词：三电平；PWM整流器；双环控制；单位功率因数；中点电压平衡 例二： 数字控制400Hz 三相四线高功率因数PWM 整流器研究 摘要 根据航空电源系统中AC-DC 静止变流器的应用需要，设计了一套数字控制400Hz 三相四线高功率因数PWM 整流器系统。传统的直接电流控制方法由于被控量是交流信号，因而存在着相位静差问题，本文采用基于dq 同步旋转坐标变换的空间矢量控制方法，实现了输入电流与输入电压间的相位无静差控制，实现了高功率因数目的。针对三相四线结构输出串联电容均压问题，本文提出了输出串联电容均压环与中线电流环串联的双闭环控制方法，实现了输出串联电容均压控制。最后在理论分析与仿真的基础上搭建了3kW 原理样机，仿真和实验结果均验证了该系统控制方法的正确性与可行性。 关键词：400Hz 三相四线 高功率因数 无静差控制 均压控制 Digital Controlled 400Hz Three-Phase Four-Wire PWM Rectifier with High Power Factor Abstract In this paper, a digital controlled 400Hz three-phase four-wire PWM rectifier with high power