AC-AC Converter With High Frequency Link

电力电子变换技术在过去六十年里已经取得较大发展，人们在AC/DC、DC/DC、DC/AC等领域内的中、小功率变换器研究已经取得了显著成就。然而，对AC/AC变换器研究仅局限于可控硅变换器、矩阵变换器和交流斩波器等交流电网与负载无电气隔离领域。目前国内外对于AC/AC变换技术的研究仍处于初级阶段，寻找一种结构简洁、控制模式方便的主拓扑具有很重要应用意义。 本文通过了解各种典型和新兴的交流变换器主拓扑结构及其性能特点，对高频连接型全桥桥式变换器的电路拓扑、控制原理等进行了深入研究，设计出一款可运行恒压、恒流两种工作模式的AC-AC变换器。经过仿真分析、实际软硬件电路设计等步骤后完成了该变换器样机...In the past 60 years, power electronic conversion technology has achieved great development. People study in AC/DC, DC/DC, DC/AC fields, in medium and small power converter, has made remarkable achievements. However, the study of AC/AC converter is very little, only to do some research about the SCR converter, matrix converter and AC chopper, there is no electrical isolation between their input an...学位：工学硕士院系专业：物理与机电工程学院_机械设计及理论学号：1992012115272

A finger pulse detecting device based on photoelectric sensor

根据红外光谱法血氧饱和度测量原理,以AVr单片机为开发平台,设计了一种简易式基于光电传感器的指夹式脉搏检测装置。硬件设计上充分利用了AVr单片机内部的功能模块,使外围元件个数减到最少,功耗降到最低,而且所设计的调理电路对信号进行调理输出,稳定可靠;软件设计上实现了信号处理、信息显示等功能。实验样机的初步测量结果表明,在安静的状态下脉搏数据误差在3%之内。According to the measuring principle of infrared spectrum method for blood oxygen saturation, with AVR MCU as the controller, a simple finger clip type pulse detecting device is designed based on photoelectric sensor.The internal modules of the AVR MCU are fully used in hardware design in order to keep the number of external components and the power consumption to the minimum.The output signals from conditioning circuit are stable and reliable.The functions of signal processing, information display and so on are realized in software.The experimental results indicate that the measuring error is within 3% in quiet

Design of a high-power constant current source based on power switch

针对交流恒流的使用要求,设计了一种基于ATMEgA16单片机的大功率交流恒流源控制系统。采用一种改进的SPWM计算方法,由ATMEgA16单片机产生SPWM方波,精确、快速控制H桥逆变电路。同时采用闭环控制,电流传感器时刻监测输出电流反馈到单片机,在一个载波周期内由单片机做出调整,达到输出电流恒流。实验证明,系统具有输出电流可调节范围大、动态响应好、生产效率高等特点。For the application requirements of AC current sources, a control system for high-power AC current source based on ATMEGA16 is introduced in this paper.An improved SPWM calculation method is prestented.The system uses a microcontroller to generate precise SPWM rectangular waves and controls the H-bridge inverter circuit accurately and quickly.Meanwhile, with the closed-loop control completed by the current sensor monitoring the current outputs and providing feedback, the microcontroller can make adjustment in a carrier period to keep the current outputs invariable.The tests show that the system has a wide adjustable output range, good dynamic response, high production effi ciency, and so on

Rotation rate analyses and measuring methods of DC motors

为提高直流电机的速度检测效率,实现规模化生产中电机速度指标的在线检测,对现有直流电机的速度检测方法进行了总结。通过对直流电机电枢电流的分析,得出电枢电流的时间响应由衰减的指数分量、直流分量和正弦分量构成,从而得出电枢电流携有正弦分量的结论,进一步推导出正弦分量与电机转速的关系,由此得到了一种根据电机电枢电流测量电机转速的方案。经在线实际测量使用,结果表明,该方案具有简单、可靠、高效的特点。In order to increase rotation rate detection efficiency of DC motors and achieve online detection of rotation rates in mass production, existing rotation rate detection methods for DC motors are summarized in this paper.Based on the analyses of DC motor armature current, the conclusion is got that time response of armature current consists of attenuation index component, DC component and sinusoidal component.Thus it comes to the conclusion that armature current has sinusoidal component.Further the relationship between sinusoidal components and the rotation rate is deduced.So a solution for rotation rate measurement is given according to the armature current of DC motor.The results of online practical tests show that the method is simple, reliable and high effi ciency