矿井宽压输入自适应电源系统设计

针对现有矿用电源适应的电压波动范围窄、使用不便等问题,提出一种基于全控桥移相整流技术的AC80～830V宽压输入自适应电源系统设计方案。该电源主电路采用晶闸管控制方式,控制电路采用PIC16F1937单片机实现瞬时电压跟踪控制,使得输入电压变动时输出电压稳定工作在DC110～350V。仿真实验结果表明,该电源系统工作稳定、可靠。

一种矿用超宽输入电压范围自适应电源

针对现有矿用电源存在取电不便、体积大、抗波动能力差、电路复杂、成本高等问题,设计了一种矿用超宽输入电压范围自适应电源。该电源采用输入串联型反激变换器,可降低功率开关管的电压应力,将超宽输入电压转换为稳定的直流电压。试验结果表明,在输入电压为AC85~900 V时,电源输出电压最大误差仅为1.1%,纹波电压不超过139 mV,效率高达87.4%;绝缘耐压试验中漏电流不大于1.53 mA,绝缘电阻不小于50 MΩ,满足GB 3836.4—2010《爆炸性环境第4部分:由本质安全型“i”保护的设备》中防爆要求。

基于C8051单片机的电火花线切割自适应电源研究

对电火花线切割脉冲电源的原理进行了探讨与分析,介绍了一种基于C8051单片机的新型电火花线切割自适应电源的设计方法。对放电状态进行在线检测,该系统能够通过对放电脉冲的自适应调整,使极间放电状态总是处于理想状态,能够较好地适应加工条件的剧烈变化,大大提高了线切割加工过程的稳定性和加工品质。

智能电网中基站的自适应电源管理方案

为最小化能耗带来的花费,考虑到用户的需求,研究一种结合无线基站、可再生能源和电力网的综合优化绿色通信模型。提出一种基于基站供电环境历史数据(如可再生能源产电量、电价、无线负载)的自适应电源管理方案APM(adaptive power management)。仿真结果表明,自适应电源管理方案能够在考虑基站功耗的前提下,很好地适应供电环境,根据供电化境的变化,自适应调整供电方案,减少了购电花费和CO2的排放。

一种宽输入自适应电源

文中提出一种宽电压（85-825V）自适应电源的设计方案，并论述其软硬件设计方法。该电源主电路采用晶闸管控制的方式，控制电路采用基于uPD78F9202单片机的PWM技术和瞬时电压跟踪控制策略。该电源实现了对宽范围输入电压的自动适应，具有很高的实际意义和应用价值。

基于Protel 99 SE电磁齿轮自适应电源电路设计

在对电磁磁力齿轮了解的基础上,掌握了其电源电路工作原理,基于Protel 99SE设计出自适应电源的功率模块并给出了相应参数,之后设计出了放大电路并给出相应的参数。该电源电路能够较好的适应电磁磁力齿轮,通过多学科知识的运动实现了对磁力齿轮的精确控制。

宽压自适应开关电源的设计

针对煤矿井下设备对开关电源的特殊要求,提出一种采用自适应交流调压电源与普通开关电源相结合的设计方案。重点阐述自适应交流调压电源的设计原理以及电路的设计方法。仿真分析和实验结果表明,该设计方案可行。

GE和BAE系统将共同探索下一代自适应电源系统在空战中的应用

7月19日,BAE系统公司和GE公司宣布,将针对下一代自适应电源管理系统在空战领域的应用开展合作。自适应电源管理系统可以更有效地利用电力,有效提高作战飞机的作战能力。GE公司已将电力演示设备交付给BAE系统公司的实验室,以开始探索如何采用和使用固态电力控制器。

矿井监控电源设备的现状及发展趋势

针对矿井监控系统电源设备的现状,结合矿井特殊的应用环境,对影响其工作的不利因素进行了分析,提出了发展趋势,即输入电源宽压自适应、电能感应耦合非接触传输、本安电源大容量化、本安电源远距离传输、智能化控制及故障自诊断、电池容量预估智能化、备用电源时间延长、本安电源抗干扰能力增强等,并指出实现方案,对相关研究提供了新的思路。

同杆四回线纵联差动保护新方案

对于传统的纵联差动保护直接应用于同杆四回线输电线路时,易受零序互感及分布电容电流影响,致使保护产生误动或拒动。为此,首先深入研究了同杆四回线输电线路,再利用12序分量法对其线路进行参数解耦,得到相互独立的序分量,并提出了相应的反序负序网络;然后利用该反序负序分量的特征以及综合考虑电流互感器饱和等问题,从而推导出新的纵联差动保护判据。大量的PSCAD/EMTDC仿真结果表明:本方案简单可靠,不受零序互感、分布电容电流、故障类型及过渡电阻等因素影响;同时对于电源容量的变化自适应能力较强。

JM9142型单色多频高分辨率显示器

本文介绍了JM9142型单色多频高分辨率显示器特性、工作原理及测量结果.

Cooperative wireless networks for better green services

In order to guarantee the overall return on investment (ROI), improve user experience and quality of service (QoS), save energy, reduce electra magnetic interference (EMI) and radiation pollution, and enable the sustainable deployment of new profitable applications and services in heterogeneous wireless networks coexistence reality, this paper proposes a cross-network cooperation mechanism to effectively share network resources and infrastructures, and then adaptively control and match multi-network energy distribution characteristics according to actual user/service requirements in different geographic areas. Some idle or lightly-loaded base stations (BS or BSs) will be temporally turned off for saving energy and reducing EMI. Initial simulation results show that the proposed approach can significantly improve the overall energy efficiency and QoS performance across multiple cooperative wireless networks.

Adaptive resource allocation for multi-user multi-server power-line communication OFDM systems

The bits and power allocation model of adaptive power-rate mixture for multi-user multi-server power-line communication systems was analyzed with the restrictions of maximal total power,fixed rate for each real time (RT) user,minimal rate for each non-real time (NRT) user,maximal bits and power for each subcarrier in each orthogonal frequency division multiplexing (OFDM) symbol. An algorithm of resource dynamic allocation in the first OFDM symbol of each frame and resource optimal adjustment in the latter OFDM symbol of each frame was proposed. In the first OFDM symbol of every frame,resource is firstly assigned for RT users so as to minimize their total used power until satisfying their fixed rates; secondly the remainder resource of power and subcarriers are assigned for NRT users so as to minimize their total used power until satisfying their minimal rates also; lastly the remainder resource is again assigned for NRT users according to the proportional fairness strategy so as to maximize their total assigning rate. In the latter OFDM symbol of each frame,bits are swapped and power is adjusted for every user based on the resource allocation results of anterior OFDM symbol. The algorithm is tested in the typical power-line channel scenarios and the simulation results indicate that the proposed algorithm has better performances than the classical multi-user resource allocation algorithms and it realizes the multiple aims of multi-user multi-server resource allocation for power-line communication systems.

Trade-off Optimization for Scalable Video Coding Streaming in Relay-Based OFDMA Networks

To achieve an optimal trade-off between video quality and energy efficiency in the uplink streaming of multi-user Scalable Video Coding (SVC) videos in relay-based Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks, a cross-layer design framework that jointly selects the Transmission Policy (TP) for SVC video frames, assigns OFDMA subcarriers, and allocates power for each subcarrier is proposed. We apply the dual decomposition method to the problem, and obtain a TP selection subproblem for each SVC video adaptation and a resource allocation subproblem of Joint Subcarrier, Relay and Power Allocation (JSRPA). A second level of dual decomposition is used to divide the JSRPA problem into independent subcarrier subproblems. The proposed Crosslayer Trade-off Optimization (CTO) algorithm is sub-distributed with significantly low complexity. A performance evaluation with typical SVC video traces demonstrates that the proposed algorithm is able to converge and efficiently achieve the optimal trade-off between the video quality and energy consumption at the MSs for uplink SVC streaming.

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.

Self-powered electrochemical anodic oxidation： A new method for preparation of mesoporous Al2O3 without applying electricity

Anodic oxidization （AO） is one of the most important methods available for fabricating mesoporous Al2O3 , which can be conducted at either high potential or low potential; however, the need for an external electricity power source limits its applications. In this work, a novel self-powered electrochemical anodic oxidization （SPAO） system was introduced for preparing mesoporous Al2O3 , by using newly-invented triboelectric nanogenerator （TENG） arrays driven by wind power. Using the controllable voltage output of the TENG arrays, the SPAO system was shown to regulate the pore depth and pore size of the mesoporous Al2O3 . In contrast to traditional AO systems, this technique takes advantage of the high output voltage of TENG arrays without any additional energy costs. In addition, the SPAO system can be used for the preparation of other mesoporous materials.