共查询到18条相似文献,搜索用时 109 毫秒
1.
2.
分析了配电系统中静止无功补偿器(SVC)的各种控制方法。对于配电系统快速冲击性负载应用SVC进行动态无功补偿。文中提出了一种全新的控制策略及触发方法.并对该控制策略和方法在实际工程中的控制效果进行了介绍, 相似文献
3.
介绍了GPRS模块PIML-900/1800的功能特点及该模块在MSP430控制系统中的连接方式,并详细介绍了应用该模块进行数据传输时的控制流程,最后浅谈了应用模块时应注意的问题。对采用国产PIML模块进行GPRS数据传输系统的设计有一定的借鉴。 相似文献
4.
交流输电线路静止无功补偿器(SVC)控制系统 总被引:2,自引:2,他引:0
静止无功补偿器(SVC)系统是目前世界上柔性交流电输电系统发展的一个重要方向,具有增加输电网络的传输容量,提高输电网络运行稳定性等优点,相对传统的无功补偿方法更具有实时性和精确性。根据无功补偿的原理分析了SVC的基本组成和工作原理,提出SVC控制系统的基本模型,给出模型中各模块的主要功能,同时从整体运行的角度提出了控制系统的保护措施。 相似文献
5.
6.
GSM/GPRS模块SIM100-E在无线抄表系统中的应用 总被引:5,自引:0,他引:5
介绍了GSM(全球移动通信系统)/GPRS(通用分组无线电业务)模块SIM100-E的硬件接口特性、功能和AT命令,以及短消息模式下的PDU格式和数据编码方式,并详细介绍了该模块在无线抄表系统中的作用以及使用方法,给出了该模块在系统中的硬件连接实图和部分关键代码,其中,硬件部分采用AT89S52单片机控制该模块,软件部分为KEILC51编写的C代码程序。该模块可发送和接收抄表系统中所有的抄表信息,增加系统的灵活性,降低系统成本及功耗。 相似文献
7.
介绍了一种基于Altera公司大规模可编程逻辑器件EPF10K10的多功能出租车计费器系统.介绍了该计费器系统的主要组成单元--信号输入模块、数据转换模块、动态扫描模块、数码管控制模块及译码显示模块等的设计方法与技巧,同时给出了详细的仿真波形. 相似文献
8.
9.
10.
11.
12.
The newly standardized H.264/SVC enable multimedia suppliers to provide video bitstream with temporal, spatial and quality scalabilities to meet various needs of end users. Its bitstream scalability characteristic is also especially suitable for multimedia applications under merged heterogeneous networks with different network protocols, capacities and throughputs. Although the network environment, to some extent, provides security protection against the illegal users, it is not enough to protect against the authorized users from digesting contents beyond its authorization. Hence the issue of content protection for the H.264/SVC has aroused researchers’ interests in recent years. In this paper, we present an efficient bitstream-oriented protection scheme for the H.264/SVC in a compression friendly and format compliant manner. The encryption is implemented on the Network Abstraction Layer (NAL) unit level. To improve the computational efficiency as well as to provide sufficient security, selective cryptographic algorithms with different computation cost are employed for different content level of SVC according to its significance. The I slice NAL units from the base layer of SVC bitstream are encrypted with the symmetric AES algorithm in Cipher Block Chaining mode. And the other NAL units are protected by simplified XOR cipher. Furthermore, a robust key management (key generation and distribution) mechanism is also discussed in this paper. The security analysis and simulation results further verify that the proposed methods can effectively protect the H.264/SVC bitstream at low computational cost. 相似文献
13.
《Signal Processing: Image Communication》2009,24(3):214-228
Recently, scalable video coding (SVC) has emerged as a promising video format for applications of multimedia communication. An SVC bitstream can be easily truncated (adapted) in spatial, temporal, and SNR dimensions to meet various characteristics of terminals and connections. Though SVC allows simple and flexible truncation of a coded bitstream, there still need to be efficient means to support the adaptation in different scenarios. In this paper, we review standard tools and supporting methods for SVC adaptation. We point out the practical questions and accordingly describe potential solutions to these questions. The paper also discusses two key standard tools in detail, namely MPEG-21 AdaptationQoS and SVC priority_id. 相似文献
14.
可伸缩视频编码是目前国际上视频技术研究的热点。联合视频组在近年来围绕可伸缩视频编码(SVC)展开了大量的研究工作,提出了作为H.264/AVC扩展集的SVC方案,实现了时域、空域和质量等三个维度上的可伸缩性,而其中基于视频尺寸(空域)的分层是这一方案的基本结构。因此,本文研究了基于H.264/AVC的空域可伸缩编码技术的基本结构和技术要点,并分析了这一技术在流媒体系统中应用所带来的好处。 相似文献
15.
本文介绍了一种用于SVC的高速数据通信系统,给出了数据通信系统的硬件接口电路,阐述了设计双CPU控制系统的方法及要点。实践证明,该系统能保证CPU与RAM稳定、实时的交换数据。 相似文献
16.
为了改善电网稳定性和提高功率因数,提出了一种静止无功补偿装置;介绍了无功补偿的分类,以及静止无功补偿装置的补偿原理,利用MATLAB软件对SVC进行仿真,仿真结果证明了SVC具有的很好的补偿效果。 相似文献
17.
该文提出了一种通过加装带滤波器的静止无功补偿器(SVC),使负序引起的不平衡功率和谐波功率流入SVC,最终达到平衡系统目的的方法;提出基于前馈-反馈复合控制的SVC不平衡负荷补偿方法,将电压闭环控制与三相不平衡控制相结合、功率因数闭环控制与三相不平衡控制相结合,以达到适应各种工况的需求。最后,该文在SVC相关理论研究的基础上搭建了仿真模型,仿真结果表明该文提出控制方法的正确性和可行性。 相似文献
18.
A static VAr compensator (SVC) using a three-level GTO voltage source inverter (VSI) is presented for high-voltage, high-power applications. The three-level VSI has lower harmonic components and higher DC-link voltage than the two-level VSI and thus can be operated at lower switching frequency (fsw<500 Hz) without excessive harmonic contents. From the DQ-transformed equivalent circuit of the presented SVC system, DC and AC analyses are carried out to find the steady-state and the dynamic characteristics of the system. Based on the open-loop transfer function of the system, a controller is designed to achieve fast dynamic response. The experimental results confirm the theoretical analyses and controller design 相似文献