浅谈通信电源系统维护

本文讲述了通信电源的系统组成及通信电源在通信网络中的重要性。并对通信电源中的开关电源、蓄电池、动环监控的相关知识进行介绍。近年来,随着通信设备的不断更新,对通信电源也提出了更高的要求,因此做好对通信电源的维护具有重要意义,直接影响着通信网络的安全平稳运行。

电源与信源Unite模块化产品设计研究与实践

本文解释了电源与信源Unite模块化产品在顺应智能家电与工业4.0的发展趋势中的基础地位,通过研究电源与信源Unite模块化产品需要解决的核心问题,整理主旨方法,并以产品设计实践的方式阐明了电源与信源Unite模块化产品的具体物化结构,对进行电源与信源集成适配及对应模块化互换的研究具备一定的推进作用。

通信枢纽楼能耗运行分析研究

如何在业务量不断增加,电源容量无法扩容的情况下,更好地解决供电能力紧张、机房装机位不足、机房散热等问题,是本论文的研究意义所在。本文通过对S省通信枢纽楼能耗运行分析,给出以上难点的合理化建议和建设指导原则。

自动化设备运行可靠性分析

根据大连供电公司自动化设备在运行中暴露的问题,分析了出现问题的原因,并通过远动电缆屏蔽的良好接地、不间断电源的综合防雷及分离遥信和装置工作电源等措施,提高了自动化设备的运行可靠性。

CLOSE-LOOP DESIGN OF PULSE POWER SUPPLY FOR ELECTRICAL DISCHARGE MACHINING

The dynamic performance and the stability are essential for a system. A new circuit topology used for electrical discharge machining (EDM) power and made up of complex-pulse (voltage-pulse and current-pulse) is presented. The large-signal model of it is also derived. Based on the comprehensive analysis of the system model, the compensator is designed to make the system match better and to improve its dynamic performance and the stability under perturbations. Finally, the design methods and the analysis are verified by simulation and experimental results.

Opportunistic Relaying Schemes for Amplify and Forward Bidirectional Relay Channels with Multi antenna Sources

We consider a two-way relay network where the Amplify-and-Forward (AF) protocol is adopted by all relays in this paper.The network consists of two multi-antenna source nodes and multiple distributed single-antenna relays.Two opportunistic relaying schemes are proposed to efficiently utilize the antennas of the source nodes and the relay nodes.In the first scheme,the best relay is selected out by a max-min-max criterion before transmitting.After that,at each source,only the antenna with the largest channel gain between itself and the best relay is activated to transmit and receive signals with full power.In the second scheme,assisted by the best relay which is selected by the typical max-min criterion,both source nodes use all their antennas to exchange data,and match filter beamforming techniques are employed at both source nodes.Further analyses show that all schemes can achieve the full diversity order,and the conclusions are not only mathematically demonstrated but numerically illustrated.System performance comparisons are carried out by numerical methods in terms of rate sum and outage probability,respectively.The beamforming assisted scheme can be found to be superior to the antenna selection scheme when accurate Channel State Information (CSI) is available at the transmitters.Otherwise,the latter is very suitable.

Thermo Tank Temperature Control System Based On STM32

This paper introduced a thermo tank temperature control system based on STM32. Firstly, the temperature acquisition is real- ized by the high-lxecision electrical bridge based on constant current source. Then the augmented PID algorithm realized by software is adopteff But-terworth filter is used to convert the o.aput PWM of STM32 to current signal which is used to control the seniconductor control rectifier to adjust the temrature. Calibration check and practical application both indicated that the system was reliable, high-precision, practicable and could meet reality needs.

Adaptive controller design based on input-output signal selection for voltage source converter high voltage direct current systems to improve power system stability

An input-output signal selection based on Phillips-Heffron model of a parallel high voltage alternative current/high voltage direct current(HVAC/HVDC) power system is presented to study power system stability. It is well known that appropriate coupling of inputs-outputs signals in the multivariable HVDC-HVAC system can improve the performance of designed supplemetary controller. In this work, different analysis techniques are used to measure controllability and observability of electromechanical oscillation mode. Also inputs–outputs interactions are considered and suggestions are drawn to select the best signal pair through the system inputs-outputs. In addition, a supplementary online adaptive controller for nonlinear HVDC to damp low frequency oscillations in a weakly connected system is proposed. The results obtained using MATLAB software show that the best output-input for damping controller design is rotor speed deviation as out put and phase angle of rectifier as in put. Also response of system equipped with adaptive damping controller based on HVDC system has appropriate performance when it is faced with faults and disturbance.

Effect of PMD-induced Pulse Broadening on Sensitivity and Frequency Spectrum

The PMD-induced pulse broadening may cause the degradation ofreceiver sensitivity and has negative effects on the power spectrumof received signals. The expression s of PMO-induced pulse broadeningeffects on receiver sensitivity are derived based on the concept ofman square pulse width. The effects of PMD on the spectrum ofreceived power are analyzed in detail. Finally, the scheme isdiscussed with which the poser of a certain frequency component isextracted as a feedback control signal in a PMD compensation system.

Analyses on Four Models and Cases of Enterprise Informatization

The basic conditions of the enterprise informatization in Heilongjiang province are analyzed and 4 models are designed to drive the industrial and commercial information enterprise. The 4 models are the Resource Integration Informatization Model, the Flow Management Informatization Model, the Intranet E-commerce Informatization Model and the Network Enterprise Informatization Model. The conditions for using and problems needing attentions of these 4 models are also analyzed.

Applying Modern Communication Technology to Loss-of-Mains Protection

The protection of distribution networks is facing new challenges from an increasing amount of DG （distributed generation）. Even though current technology provides satisfactory solutions to manage this new situation, LOM （loss-of-mains protection） is still considered problematic. The solution proposed in this paper focuses on the use of a line differential protection relay. It inherently contains a suitable communication channel and provides absolutely selective protection for the feeder. Furthermore, it prevents the feeder relays from false tripping for faults on the neighboring feeder. The present trend in protection communication points towards the use of fiber optics. For line differential protection, this means a fast and high-capacity communication link which enables the implementation of many advanced protection functions. In addition, a solid foundation for such a communication link is offered by the new IEC 61850 standard and Ethernet technologies. The basic functionality of the line differential protection enables the operation of both the feeder protection and the DG protection for any fault on the feeder. Furthermore, basic LOM protection methods can be applied as backup protection for failures on the communication link.

Study on Supply Drive and Demand Drive of the Telecommunication Operation

This paper analyzes the total movement period of the development of the world telecommunication industry, and points out the basic principles of the supply and demand regulation and the market drive are important and useful to the telecommunication industry. The thesis puts forward the pertinent evaluation and the positive suggestions according to the general characteristics and individual characteristics of Chinese telecommunication industry and emphasizes the meaning of the demand drive.

Emerging of Telco Cloud

Cloud computing is the latest major evolution in computing technology. The convergence between cloud computing and tele- com networks could significantly reduce costs and bring new business opportunities for operators. Currently, traditional teleeom operators are embarrassed by the fact that the increase in revenue cannot catch up with the quick growth of users and the expansion of networks. With the introduction of the cloud computing technology, operators can virtualize the network functions through low-cost COTS IT hardware All kinds of existing services can be cloudifled and thus obtain the benefits of statistical multiplexing among IT resources. With the Teleo Cloud architecture, operators can manage both IT infrastructures and network resources intelligently in order to adapt to the dynamic demands from the application and to establish open platforms for developing new services.

The Effect of TV Captions on the Comprehension of Non-Native Saudi Learners of English

This paper investigates the effectiveness of closed captioning in aiding Saudi students who are learning ESL （English as a second language）. Research was carried out in a qualitative manner, and participants were 12 Saudi students pursuing their studies at Indiana University of Pennsylvania, USA （IUP）. Participants in the study were asked to compose a narrative after viewing a 5-minute film segment, both with and without captioning. Their responses were then analyzed, and results indicated that while captions may aid one in comprehension, they also tend to limit one＇s interpretations, reaffirming the nature of written language as an authoritative source of information.

How to Improve Efficiency of Telecom Energy

High OPEX （operation expenditure）, pollution and complicated environment are challenges which telecom operators have to conquer to improve energy efficiency. Integration and flexibility are tendencies for telecom energy solution development, also the keys to improve energy efficiency. With plentiful design and implementation experience, the author provides a three-dimensional energy matrix model to design a perfect energy system, and some practical measures of integration and flexibility are also shared from mechanical to electrical, from single site to whole network.

A Takagi-Sugeno-Kang (TSK) Power Model Using Compressed-sensing Sampling

More and more information are needed in social life and commercial production, causing significant pressure on the sampling and too much time spent on signal sampling. Compressed sensing is one emerging hotspot in signal processing which employs a special sampling method to capture and represent compressible signals at a rate significantly below the Nyquist rate. In this paper, a Takagi-Sugeno-Kang (TSK) Model based on compressed-sensing sampling theorem is proposed for grinding power. It is further tested by using the actual production data, and the algorithm performance in grinding power model is also analyzed. The experiments show the validity and effectiveness of the proposed modeling method and its bright application foreground in other fields with similar features, such as power, metallurgy and so on.

Adaptive Energy-Efficient Power Allocation for DAS with Imperfect Channel State Information and Antenna Selection

Considering that perfect channel state information(CSI) is difficult to obtain in practice,energy efficiency(EE) for distributed antenna systems(DAS) based on imperfect CSI and antennas selection is investigated in Rayleigh fading channel.A novel EE that is defined as the average transmission rate divided by the total consumed power is introduced.In accordance with this definition,an adaptive power allocation(PA) scheme for DAS is proposed to maximize the EE under the maximum transmit power constraint.The solution of PA in the constrained EE optimization does exist and is unique.A practical iterative algorithm with Newton method is presented to obtain the solution of PA.The proposed scheme includes the one under perfect CSI as a special case,and it only needs large scale and statistical information.As a result,the scheme has low overhead and good robustness.The theoretical EE is also derived for performance evaluation,and simulation result shows the validity of the theoretical analysis.Moreover,EE can be enhanced by decreasing the estimation error and/or path loss exponents.

A Magnetron Power Supply with Transition-Mode Zero-Voltage-Switching Inverter

This paper presents a transition-mode zero-voltage-switching inverter for the cooker magnetron of household microwave ovens. The inverter drives a leakage transformer to generate the required high voltage and stabilized current. For achieving zero-voltage switching, a transition-mode driver L6561 is utilized to detect the ending of transformer resonance and drive an insulated-gate-bipolar-transistor. As transistor is conducted, rectified direct-current voltage drives the transformer. While transistor is cut off, transformer resonates with a parallel capacitor. Transistor conduction time and magnetron power are controlled with a 16-bit digital signal controller dsPIC30F4011. For widening the working range, transistor conduction time is set to be inversely changed with line-frequency input voltage. To demonstrate the analysis and design of this paper, a 1 kW inverter circuit is built. Experimental results show the feasibility and usefulness of the designed magnetron power supply.

High-Frequency Digital Controller Applied to Voltage Regulator Modules

Digital controllers are an interesting option for the next voltage regulator module （VRM） generation due to their wide programming possibilities. This paper discloses a very interested candidate to control DC-DC power converters, the Digital Signal Controller （DSC）. For that matter, a study was done by carrying out simulations and experimental results. Moreover, an additional voltage-input feed-forward （IVFF） algorithm is given in order to show the benefits of this technology. Finally, a complete analysis of the quantization effect is presented, and its influence over the controller performance is included.

Standard for Universal Power Adapter for Mobile Terminals

This paper introduces the choices of the technology solutions pertinent to the industrial standard of Chinese communications industry, YD/T 1591 Technical Requirements and Test Method of Charger and lnterface for Mobile Telecommunication Terminal Equipment, as well as its development and revision process. It also elaborates the technology contents for Recommendation of Improving the Standard ITU-TL.1000.