基于SPWM的高效能电网充放电控制算法研究

本研究采用了系统建模和仿真实验的方法。针对电网充放电系统进行建模,分析系统中各个关键组件的工作原理和特点,基于此设计了基于SPWM的充放电控制算法。接下来,开展了一系列的仿真实验,验证了基于SPWM的充放电控制算法的效果。比较了该算法与传统的控制方法的性能差异。结果表明,SPWM控制能够有效维持电网正常运作。

基于绝对潮流的关键线路辨识方法

针对电力系统中关键线路辨识受系统的运行状态影响、很难快速准确地进行辨识的问题,结合电网实际潮流、绝对潮流、节点性质以及线路输电容量等因素,根据发电机支路功率分布因子、绝对潮流因子和线路权重因子,提出了基于加权绝对潮流因子来进行关键线路辨识。采用连续攻击后系统的切负荷量及全局效能函数对系统的脆弱性进行评估,经IEEE-39和IEEE-57节点系统算例对比了采用绝对潮流和潮流进行关键线路辨识的效果,验证了算法的有效性。结果表明,本文所提出的算法可以提高关键线路辨识的准确度和速度,对于指导电力系统规划和调度运行具有指导意义。

基于电气介数的电力系统脆弱线路辨识

为了防止大规模停电事故的发生,电力系统需要对电网中的脆弱线路进行辨识并对其进行保护。文中用到的电气介数是基于直流潮流计算的,综合考虑了电气距离和容量分布,分析了其对网效性能的影响。由此得出结论,电气介数越高,电网中的线路越脆弱,当这些线路受到攻击时,电网效能下降的越快,由此得出了电气介数与电网中线路脆弱性的关系。

Energy Efficiency Optimization in Relay-Assisted Networks with Energy Harvesting Relay Constraints

In this paper we consider data transmission in a decode-and-forward(DF)relay-assisted network in which the relay is energy harvesting(EH) powered while the base station(BS) is power-grid powered.Our purpose is to maximize the BS's energy efficiency(EE) while making full use of the relay's renewable energy and satisfying the specific average throughput requirements.In contrast to existing literature on energy harvesting system which only considers the radio transmission power,we take the static circuit power into account as well.We formulate the EE optimization problem and prove that the EE of the BS and relay are both quasiconvex in the instantaneous transmission rate.Then we divide the complex optimization problem into two point-to-point link level optimization parts and propose an energyefficient resource allocation(EERA) scheme in which power control and sleep mode management are jointly used.The simulation results demonstrate that EERA may achieve good energy saving effects.We also compare the EE of an energy harvesting relay system with a power-grid powered one and provide more insight into the EE problem of energy harvesting relay system.

Energy Efficient Power Allocation for Relay-Aided D2D Communications in 5G Networks

As one of the key technologies for the fifth generation(5G) wireless networks,device-to-device(D2D) communications allow user equipment(UE) in close proximity to communicate with each other directly.Forwarded by a relay,the relay-aided D2D(RA-D2D) communications can not only be applied to communications in much longer distance but also achieve a high quality of service(Qo S) .In this paper,we first propose a two-layer system model allowing RA-D2 D links to underlay traditional cellular uplinks.Then we maximize the energy efficiency of the RA-D2 D link while satisfying the minimum data-rate of the cellular link.The optimal transmit power at both D2 D transmitter and D2 D relay sides is obtained by transforming the nonlinear fractional programming into a nonlinear parameter programming.Simulation results show that our proposed power allocation method is more energy efficient than the existing works,and the proposed RA-D2 D scheme outperformed direct D2 D scheme when the distance between two D2 D users is longer.

Analysis on Conditions of Northwest,North China and Shandong Power Grids Interconnection

This paper analyzes the possibility and benefits of interconnection of Northwest Power Grid with North China and Shangdong power grids. With different energy resources and power demand patterns, these three power grids have large potential benefits in future interconnection.

Reliability-aware mapping and links voltage assignment for energy-efficient networks-on-chip

As feature sizes shrink,low energy consumption,high reliability and high performance become key objectives of network-on-chip(NoC) design.In this paper,an integrated approach is presented to map IP cores onto NoC architecture and assign voltage levels for each link,such that the communication energy is minimized under constraints of bandwidth and reliability.The design space is explored using tabu search.In order to select optimal voltage level for the links,an energy-efficiency driven heuristic algorithm is proposed to perform energy/reliability trade-off by exploiting communication slack.Experimental results show that the ordinary energy optimization techniques ignoring the influence of voltage on fault rates could lead to drastically decreased communication reliability of NoCs,and the proposed approach can produce reliable and energy-efficient implementations.

Efficient perovskite solar cells based on novel three-dimensional TiO2 network architectures

Mesoscopic lead halide perovskite solar cells typically use TiO2 nanoparticle films as the scaffolds for electron-transport pathway and perovskite deposition. Here, we demonstrate that swelling-induced mesoporous block copolymers can be templates for producing three- dimensional TiO2 networks by combining the atomic layer deposition technique. Thickness adjustable TiO2 network is an excellent alternative scaffold material for efficient per- ovskite solar cells. Our best performing cells using such a 270 nm thick template have achieved a high efficiency of 12.5 % with pristine poly-3-hexylthiophene as a hole transport material. The high performance is attributed to the direct transport pathway and high absorption of scaf- folds, small leakage current and largely reduced recombi- nation rate at interfaces. The results show that TiO2 network architecture is a promising scaffold for meso- scopic perovskite solar cells.