GPIB接口的FPGA实现

GPIB接口是测试仪器中常用的接口方式。通过将接口设计分解为同步状态机设计和寄存器读写电路设计，采用Verilog语言实现了满足IEEE488．1协议的IPCore设计。将此IPCore固化到FPGA芯片中即可实现GPIB各种接口功能。     

GPIB接口的FPGA实现

介绍了GPIB控制器的总体结构，论述了基于FPGA的GPIB接口设计，给出了源方挂钩接口功能的状态图和完整的程序代码，同时对该程序代码进行了编译、综合和仿真。     

基于LabVIEW的数据采集卡PXIe-4499自动校准系统

首先,通过GPIB/GPIB线和USB/GPIB线将FLUKE5522A、Agilent33120A、PXIe-1062Q控制器和PXIe-4499数据采集卡连接组成了硬件系统;然后,在图形化编程软件LabVIEW和虚拟仪器驱动程序的基础上,设计了数据采集卡PXIe-4499自动校准系统,该系统能够提高数据采集卡的校准效率,具有一定的推广价值.     

基于GAP技术的网络隔离设备的设计

简要介绍GAP技术的原理,提出一种基于现场可编程门阵列(FPGA)的实现方案.通过详细分析SCSI协议控制器的设计和SDRAM IP核的应用,将SCSI协议控制器、SDRAM控制器和核心控制器集成在一个FPGA中实现.经测试,这种方案比MCU SCSI协议控制器的方案具有更高的可靠性和兼容性.     

基于P89C669微控制器的MODBUS协议转换器设计与实现

基于P89C669微控制器和计算机数据通信技术,设计了MODBUS协议转换器,实现了MODBUS网络的主控设备与RTU(远程终端单元)之间的数据转换,并在电力系统220 kV主变风冷控制中用于变电所站内自动化监控计算机系统的MODBUS网络和PLC(可编程逻辑控制器)的数据通信,使站内自动化监控系统可根据主变油温、负荷电流等运行参数对风冷机组和油泵进行实时调控。     

CAN-Ethernet总线通信协议转换器的研究

随着先进制造技术的数字化、网络化、智能化,现场总线技术和嵌入式技术相结合必将产生深远的影响。文中介绍基于ARM的CAN-Ethernet总线通讯协议转换器的总体设计和实现Modbus TCP的设计架构,Modbus/TCPIP服务器端的设计。采用CAN总线协议与Modbus/TCPIP协议进行转换的方式来实现便捷低成本的协议转换器,着重介绍了设备的固件程序,驱动程序,应用程序的设计和具体实现。     

基于GPIB的光纤收发器系统的设计与实现

对光纡收发器及GPIB概念和应用理论进行了概述,重点对对基于NAT9914芯片的GPIB接口的实现及其软硬件设计进行了探讨。给出了具体GPIB的硬件设计图,对光纤收发器的光电转换模块进行了选择,同时对GPIB的软件设计进行了简要探讨。通过后续的实物实验,得到了该光纤收发器设计上的合理性与有效性结论。     

一种电感电流同步控制和采样DC转换器设计

双向DC控制器的控制指标衡量主要包括采样和控制两个方面,本系统从电流采样角度出发,设计一种电感电流同步控制和采样转换器,在控制周期的固定位置采集数据,从而达到稳定采样的目的,且控制方式采用集中式管理分布式控制方案,可以实现多模块的并联,为后期扩展留下基础.尤其适用于DC转换器中需要对电感电流进行采样的装置,该转换器主要用来实现采样和控制同步.     

基于GPIB总线的移动台自动测试系统解决方案

本文介绍了GPIB接口总线技术,然后从硬件组成、软件体系结构和应用软件3个方面详细阐述了基于GPIB总线的移动台自动测试系统的设计和实现方案.系统方案最大限度地实现了测试的自动化,并且具有一定的代表性,适用于一般自动测试系统的开发.     

射频功率校准仪的GPIB接口开发

为了满足组建以PC为中心的射频功率自动校准系统的需求,提高射频功率校准及射频功率检测的效率。本文利用NAT9914GPIB接口专用芯片设计了一种以ARM为核心的射频功率校准仪的GPIB接口电路．并详细讨论了GPIB接口功能的软件实现方法,并给出了软件设计的流程图。基于此种方法设计的GPIB接口卡已成功应用于射频功率自动校准系统中,取得了良好的效果,实现了GPIB的基本功能。对相关工程技术人员有一定的借鉴作用。     

Posicast-based digital control of the buck converter

The analysis, design, and microcontroller-based implementation of a digital controller using a Posicast element are presented for the buck converter. Posicast is a feedforward compensator that eliminates overshoot in system response, but the traditional approach is sensitive to variations in natural frequency. The new method described here reduces the undesirable sensitivity by using Posicast within a feedback loop. Compared to classical proportional-integral-derivative (PID) control, the new control results in lower noise in the control signal because the controller has a lower gain at high frequency. Furthermore, the authors' experiments indicate that the new controller is less sensitive to the inherent time delay associated with a digital controller for a dc-dc converter. The authors present a straightforward method to design controller parameters from the small-signal averaged model of the converter dynamics. Experimental results for a PID-controlled converter and Posicast-type controller are also compared.     

Modeling and controller design of a current-mode controlled converter

In this paper, the reduced-order dynamic modeling and controller design of a push-pull DC-DC converter with current-mode control are presented. First, the small-signal equivalent circuit of the converter and its corresponding transfer function model are found. Then the selection of slope compensation and the model reduction are performed using the concept of dominant energy mode. Based on the reduced converter models, a quantitative design procedure is derived to find the parameters of the closed-loop controller such that the prescribed regulating specifications can be matched. Theoretic bases, the design and implementation of the proposed controller are described in detail. The performance of the converter and the validity of the proposed controller are demonstrated by some simulation and experimental results.<>     

Predictive Digital-Controlled Converter With Peak Current-Mode Control and Leading-Edge Modulation

The main theme of this paper is to present the digital controller design of a power converter with predictive peak current-mode (PCM) control and leading-edge modulation. The advantages of the control and modulation technique include the reduction of the sampling frequency of the A/D converter, no need of slope compensation, and the provision of a fast dynamic current response. The discrete-time model of the converter is presented as the fundamental to digital controller design and followed by the digital controller design. Moreover, the effect of predictive PCM control with leading edge modulation on limit cycle is analyzed. It is known that the limit cycle can be effectively suppressed as the converter has a predictive PCM control and leading edge modulation. Experimental results will be included to support fully the theoretical analysis.      

A novel ac-ac buck-boost voltage regulator with unity input power factor

This paper describes the design and control of a novel ac-ac buck-boost converter. In this new configuration, an ac-to-ac converter is connected between the ac mains and the load to provide regulated ac output voltage. Two topologies of the ac-to-ac converter are suggested and the current controller strategy is presented. The new regulator has nearly unity input power factor for a change in the load voltage from 10% to more than 200% of the supply voltage. The four-quadrant operation of the proposed controller enables it to accept reactive loads. Theoretical analysis and practical controller implementation using the DSP controller board are presented.     

An adaptive digital controller for a unity power factor converter

This paper describes an adaptive digital controller for a unity power factor AC-DC power converter. The controller is based on a linear large-signal model of the boost power converter. A hardware design is presented and analyzed, followed by the software implementation of the control algorithm. Issues in digital control of power converters, such as quantization effects and fixed-point representation of system parameters, are examined in the context of this system. Experimental results are presented and compared with simulations     

Analysis and Design for a Novel Single-Stage High Power Factor Correction Diagonal Half-Bridge Forward AC–DC Converter

By means of components placement, the buck-boost and diagonal half-bridge forward converters are combined to create a novel single-stage high power factor correction (HPFC) diagonal half-bridge forward converter. When both the PFC cell and dc–dc cell operate in DCM, the proposed converter can achieve HPFC and lower voltage stress of the bulk capacitor. The circuit analysis of the proposed converter operating in$ DCM+ DCM$mode is presented. In order to design controllers for the output voltage regulation, the ac small-signal model of the proposed converter is derived by the averaging method. Based on the derived model, the proportional integral (PI) controller and minor-loop controller are then designed. The simulation and experimental results show that the proposed converter with the minor-loop controller has faster output voltage regulation than that with the PI controller despite the variations of line voltage and load. Finally, a 100-W prototype of the proposed ac–dc converter is implemented and the theoretical result is experimentally verified.     

单电感多路输出BUCK电源转换器MATLAB建模及电流域设计方法

为分析单电感多路输出BUCK电源转换器(SIMO)的可行性,首先建立MATLAB模型,从算法角度验证SIMO可行性.同时为解决SIMO存在的电路复杂、面积大、及静态电流大的问题,首次提出使用电流信号设计SIMO控制器.结果表明,算法可行,电路设计方法简洁,0.13 μm CMOS工艺下三通道SIMO面积0.76 mm2,静态电流110 μA,驱动能力200 mA.     

Robust control of multimodule current-mode controlled converters

A robust controller for multimodule current-mode push-pull converters is presented. First, the small-signal equivalent circuit and the transfer function model of the multimodule converter system are obtained. Then, the selection of slope compensation and the model reduction are performed using the concept of dominant energy mode. Based on the reduced converter model, a PI (proportional plus integral) controller is quantitatively designed according to the prescribed regulating specifications using a systematic design procedure. A robust controller is proposed and augmented to improve the control performance when the parameter variations caused by system configuration change and operating point shift have occurred. The performance of the converter and the effectiveness of the proposed controller are demonstrated by simulation and experimental results     

基于UC3875的ZVZCS—PWM全桥变换控制器的研究

文中提出了一种新型次级箝位零电压、零电流变换器,分析了所提出的新型次级箝位ZVZCS电路拓扑的工作原理,详细论述了以UC3875为核心的控制器的设计及各参数的选择。最后给出了仿真及样机实验结果,进一步说明了控制器的设计及参数选择的合理性。     

GPIB测试母线在数据传输中电路的应用

介绍了GPIB通用接口母线的特点及其优势,将其应用于单片机USB-GPIB框架的数据传输系统,其中USB部分Cypress公司基于2.0协议的CY68013控制芯片,GPIB协议部分采用NI公司的NAT99l4控制芯片.