现场总线技术

现场总线(Fieldbus)是近年来迅速发展起来的一种工业数据总线，它主要解决工业现场的智能化仪器仪表、控制器、执行机构等现场设备间的数字通信以及这些现场控制设备和高级控制系统之间的信息传递问题。由于现场总线简单、可靠、经济实用等一系列突出的优点，因而受到了许多标准团体和计算机厂商的高度重视。     

现场总线工具FDT／DTM接口规范技术

FDT（Field Bus Tool）是一套用来为现场设备与控制系统或资产管理系统的软件组件之间的数据交换实现标准化的接口规范。FDT组织是一个由多家公司参与的非盈利性的国际组织，负责制定评推广FDT技术。M＆M Software美名（苏州）有限公司是FDT组织成员之一。     

浅谈现场总线在电厂中的应用

简要介绍了现场总线、现场总线系统和现场总线设备,通过对现场总线技术在电厂中的应用研究,探讨了现场总线技术在电厂中的优势和存在的问题,提出了设想。     

现场总线介绍

随着微电子技术的发展，数字通信网络延伸到工业过程现场成为可能后，于1984年左右提出的。现场总线一般定义为：一种用于智能化现场设备和自动化系统的开放式，数字化，双向串行，多节点的通信总线。其主要特征。     

现场总线技术展望

对目前主要的现场总线进行了评述，探讨了现场总线技术今后的发展方向。     

现场总线技术

随着电力企业生产规模的扩大，以火力发电机组为例，对生产过程中检测与控制精度的要求也在不断提高，不希望多次进行A/D(D／A)的信号转换。因此就要求现场仪表实现数字化、智能化，使大量的一般控制功能下放到现场仪表去解决，以减轻主机的负担；同时也要求尽量减少通信主控室的电缆。控制技术、通信技术与计算机技术的发展为解决上述问题提供了技术基础，于是现场总线就应运而生了。应用现场总线     

现场总线DeviceNet在彩色显像管业的应用

彩色显象管业是一个多工段，多工艺协调运作的复杂生产控制过程。该项目是在彩管厂的中，后工序（分别11个工段）建立产品质量跟踪监控系统，对两个分厂的人员操作，生产设备，原材料及产品进行有效的跟踪。提高了生产力和产品质量，降低能耗，合理分配利用资源。该系统成功地将罗克韦尔自动化公司的智能现场总线设备层网络应用到从过程控制到信息处理整个生产的自动化管理中，充分体现了罗克韦尔自动化公司现场总线系统的智能性，高效性和灵活性。     

现场总线技术的现状和发展趋势

论述了现场总线的现状和发展情况,并提出了我国发展该总线的规划的设想。     

现场总线技术在火电厂的应用分析

介绍了现场总线控制系统的特点及常用的现场总线类型。针对目前现场总线技术在工业控制领域的应用情况,分析了现场总线应用范围小、调试和运行维护方面无规程可依等诸多问题,从设计、安装、试验等方面提出相关注意事项及建议。     

阻塞斩波三相交交变频电源的FPGA控制实现

变频技术是重要的节能技术,所以针对低频或转速不恒定的节能设备,提出了基于FPGA数字控制的三相交交直接变频电源技术。用VHDL语言对主控芯片FPGA编写程序,其输出的高频SPWM信号经驱动电路后作为电源和负载间开关MOSFET的控制信号。MOSFET周期性地部分阻塞电源不能达到负载来改变输出电压的频率,同时在放行的时区斩波来改变输出电压的幅值。基于Matlab仿真平台,对系统进行了建模和仿真,仿真结果验证了该技术的正确性。最后给出了频率为7.14 Hz和2.63 Hz的实验波形,实验结果证明了该技术的可行性。     

Prototype hardware realization of the DSTATCOM for reactive power compensation

This paper presents the hardware prototype implementation of a hysteresis current controller (HCC) based DSTATCOM for reactive power compensation. To compensate the desired amount of reactive power, the amount of current to be injected is calculated using the instantaneous reactive power theory. The reactive component of load current is set as the reference current. The VSC is operated in the closed-loop to supply the reference current. If the VSC supplies this reference current, the DSTATCOM is said to supply the required reactive power when connected to the grid. The performance of the DSTATCOM for reactive power compensation is studied in the prototype hardware using the field programmable gate array (FPGA) controller. The issues associated with the implementation of hardware prototype are discussed and the experimental setup is found to compensate the reactive power. The Spartan-3A DSP FPGA controller is programmed using the system generator feature in the MATLAB.     

Realization of active power filter based on indirect current control algorithm using Xilinx system generator for harmonic elimination

Realization of active power filter with Model Based Design approach is presented in this paper. The approach adopts different modeling platforms as well as selection of proper hardware for step wise verification and testing. The active power filter model is developed using the Matlab/Simulink platform for single phase. The efficiency of the control algorithms such as synchronous detection method and indirect current control for active power filter is analyzed. Efficient control algorithm is developed by Xilinx system generator which is incorporated into Simulink as Xilinx tool box. Xilinx system generator provides a virtual platform for easy and effective design of the required system models in FPGA (field programmable gate array) design environments. Optimized automatic VHDL code is generated for the control algorithm which is simulated using ISE 13.2 for the generation of switching signals for the control of IGBTs of the active power filter. Suitable compensation signal is generated from the active power filter for the better elimination harmonics to improve the power quality. THD is reduced to a considered value which is able to satisfy the limits of the IEEE standard.     

考虑寿命和畸变率的极低频功率放大器开关频率优化控制策略

开关功率放大器在民用和军事中都有着广泛的应用,如电动振动试验台、通信系统和声纳探测等重要领域。文中针对应用于极低频电磁波通信的开关功率放大器,提出基于改进粒子群算法的最优开关频率控制策略,通过该方法可以在满足一定输出电压畸变率的同时,降低极低频工况的功率器件热摆幅,延长开关功率放大器的寿命。首先分析开关功率放大器的热应力控制自由度。然后对影响设备寿命长短的重要因素——热摆幅和表征输出效果的指标——谐波畸变率(total harmonic distortion,THD),这2个变量的影响因素进行研究。在此基础上,综合考虑热摆幅和THD,提出基于改进型粒子群优化算法的最优开关频率控制策略。最后,通过仿真和实验对所提控制方法进行验证。     

Common Mode Voltage Reduction Using 3D-SVPWM for 3-level CI-NPC Inverter with Hybrid Energy System

This paper elucidates Common Mode Voltage (CMV) reduction in transformerless 3-phase 3-level Coupled Inductor Neutral Point (CI-NPC) Clamped Inverter with Hybrid Energy System. The three dimensional Space Vector Pulse Width Modulation (3D-SVPWM) with Nearest State Vector (NSV) is implemented to reduce the CMV by proper selection of medium, large and small vectors in 3D cubic space region. This NSV scheme in addition to CMV reduction, reduces the capacitor voltage balancing issues and minimizes switching losses. The proposed control provides full utilization of dc link voltage with reduced harmonics. This 3-level CI-NPC inverter is energized by hybrid energy source which includes photovoltaic system and wind energy system. The results obtained for the proposed scheme through simulation and experimental setup is compared with the conventional 2D-SVPWM and 3D-SVPWM scheme. From the compared results it is evident that the proposed scheme reduces CMV to a larger extent than 2D and 3D-SVPWM control. The simulation and experimental results are verified using matlab-simulink and FPGA-Spartan-6 controller respectively.