针对多个电池储能单元间的分布式协调控制问题,提出了一种分布式储能单元分组一致性控制策略。首先,提出了一种基于分布式模型预测控制和状态约束的加权一致性算法,能考虑各储能单元的功率约束条件并快速完成多储能单元的功率分配。其次...针对多个电池储能单元间的分布式协调控制问题,提出了一种分布式储能单元分组一致性控制策略。首先,提出了一种基于分布式模型预测控制和状态约束的加权一致性算法,能考虑各储能单元的功率约束条件并快速完成多储能单元的功率分配。其次,提出了一种储能单元分组控制策略。根据荷电状态(state of change, SOC)信息设定储能单元的权重,达到改善储能单元SOC的一致性的目的。同时基于所提一致性算法,制定储能单元组间协调控制策略和储能单元效率提升策略,从而达到改善储能系统调节能力、延长储能系统寿命和提升能量转换效率的目的。最后,在Matlab中构建含8个电池储能单元的微电网系统,对所提算法和控制策略进行仿真分析。仿真结果表明,所提算法和控制策略在提升收敛速度、优化控制效果、延长储能系统寿命以及提升储能系统运行效率方面均具有一定优势。展开更多
新能源并网比例的不断攀升降低了电力系统惯量,导致系统调频能力下降。为此,开展了储能参与调频的研究。储能参与调频受到单元数量、荷电状态(state of charge,SOC)、充放电策略等因素影响,提出一种考虑频率死区的储能单元协同控制策略...新能源并网比例的不断攀升降低了电力系统惯量,导致系统调频能力下降。为此,开展了储能参与调频的研究。储能参与调频受到单元数量、荷电状态(state of charge,SOC)、充放电策略等因素影响,提出一种考虑频率死区的储能单元协同控制策略,根据SOC一致性对储能单元进行分组,不同组别单独执行下垂控制或虚拟惯量控制,简化出力控制指令。依据系统频率偏差或频率变化率进行控制指令切换,并分别设置频率偏差和频率变化率死区,以减少小扰动干扰导致储能系统频率充放电。基于Matlab/Simulink进行仿真验证,结果表明:所提控制策略简单便于执行,能够快速响应调频需求,并且能保证储能电池使用寿命。展开更多
文章针对通信电源系统易受多种因素影响的特点,开发了一种基于高级精简指令集计算机机器(Advanced Reduced Instruction Set Computer Machines,ARM)核心控制芯片和通用分组无线业务(General Packet Radio Service,GPRS)数据传输单元(Da...文章针对通信电源系统易受多种因素影响的特点,开发了一种基于高级精简指令集计算机机器(Advanced Reduced Instruction Set Computer Machines,ARM)核心控制芯片和通用分组无线业务(General Packet Radio Service,GPRS)数据传输单元(Data Transfer Unit,DTU)模块的实时监测系统。系统通过现场控制终端采集通信电源设备的运行状态信息,经模拟数字(Analog to Digital,AD)转换模块处理后,由ARM核心控制芯片发送至无线模块,最终传输至远程监控中心。此外,设计一套应急预案,包括应急预案设计原则、组织机构与职责、应急分级、启动条件与工作流程以及保障措施等,以应对电网大停电带来的经济损失。通过技术保障、装备保障、人员保障,实现抢修工作的快速响应,缩短断电时间,有效减少经济损失,确保生产生活不受影响。展开更多
In order to analyze the load carrying capacity of prestressed concrete box girders, failure behaviors of in-situ deteriorated continuous prestressed concrete box girders under loading are experimentally observed and a...In order to analyze the load carrying capacity of prestressed concrete box girders, failure behaviors of in-situ deteriorated continuous prestressed concrete box girders under loading are experimentally observed and a finite failure analysis method for predicting behaviors of box girders is developed. A degenerated solid shell element is used to simulate box girders and material nonlinearity is considered. Since pre-stressed concrete box girders usually have a large number of curve prestressed tendons, a type of combined element is presented to simulate the prestressed tendons of box girders, and then the number of elements can be significantly reduced. The analytical results are compared with full-scale failure test results. The comparison shows that the presented method can be effectively applied to the failure analysis of in-situ continuous prestressed concrete box girders, and it also shows that the studied old bridge still has enough load carrying capacity.展开更多
Coal preparation is an integral part of the coal commodity supply chain. This stage of post-mining, pre-utilization beneficiation uses low-cost separation technologies to remove unwanted mineral matter and moisture wh...Coal preparation is an integral part of the coal commodity supply chain. This stage of post-mining, pre-utilization beneficiation uses low-cost separation technologies to remove unwanted mineral matter and moisture which hinder the value of the coal product. Coal preparation plants typically employ several parallel circuits of cleaning and dewatering operations, with each circuit designed to optimally treat a specific size range of coal. Recent innovations in coal preparation have increased the efficiency and capac- ity of individual unit operations while reinforcing the standard parallel cleaning approach. This article, which describes the historical influences and state-of-the-art design for the various coal preparation unit operations, is organized to distinguish between coarse/intermediate coal cleaning and fine/ultrafine coal cleaning. Size reduction, screening, classification, cleaning, dewatering, waste disposal unit operations are particularly highlighted, with a special focus on the LI.S. design philosophy. Notable differences between the U.S. and international operations are described as appropriate.展开更多
Shared Memory (SM) switches are widely used for its high throughput, low delay and efficient use of memory. This paper compares the performance of two prominent switching schemes of SM packet switches: Cell-Based Swit...Shared Memory (SM) switches are widely used for its high throughput, low delay and efficient use of memory. This paper compares the performance of two prominent switching schemes of SM packet switches: Cell-Based Switching (CBS) and Packet-Based Switching (PBS).Theoretical analysis is carried out to draw qualitative conclusion on the memory requirement,throughput and packet delay of the two schemes. Furthermore, simulations are carried out to get quantitative results of the performance comparison under various system load, traffic patterns,and memory sizes. Simulation results show that PBS has the advantage of shorter time delay while CBS has lower memory requirement and outperforms in throughput when the memory size is limited. The comparison can be used for tradeoff between performance and complexity in switch design.展开更多
文摘针对多个电池储能单元间的分布式协调控制问题,提出了一种分布式储能单元分组一致性控制策略。首先,提出了一种基于分布式模型预测控制和状态约束的加权一致性算法,能考虑各储能单元的功率约束条件并快速完成多储能单元的功率分配。其次,提出了一种储能单元分组控制策略。根据荷电状态(state of change, SOC)信息设定储能单元的权重,达到改善储能单元SOC的一致性的目的。同时基于所提一致性算法,制定储能单元组间协调控制策略和储能单元效率提升策略,从而达到改善储能系统调节能力、延长储能系统寿命和提升能量转换效率的目的。最后,在Matlab中构建含8个电池储能单元的微电网系统,对所提算法和控制策略进行仿真分析。仿真结果表明,所提算法和控制策略在提升收敛速度、优化控制效果、延长储能系统寿命以及提升储能系统运行效率方面均具有一定优势。
文摘新能源并网比例的不断攀升降低了电力系统惯量,导致系统调频能力下降。为此,开展了储能参与调频的研究。储能参与调频受到单元数量、荷电状态(state of charge,SOC)、充放电策略等因素影响,提出一种考虑频率死区的储能单元协同控制策略,根据SOC一致性对储能单元进行分组,不同组别单独执行下垂控制或虚拟惯量控制,简化出力控制指令。依据系统频率偏差或频率变化率进行控制指令切换,并分别设置频率偏差和频率变化率死区,以减少小扰动干扰导致储能系统频率充放电。基于Matlab/Simulink进行仿真验证,结果表明:所提控制策略简单便于执行,能够快速响应调频需求,并且能保证储能电池使用寿命。
文摘文章针对通信电源系统易受多种因素影响的特点,开发了一种基于高级精简指令集计算机机器(Advanced Reduced Instruction Set Computer Machines,ARM)核心控制芯片和通用分组无线业务(General Packet Radio Service,GPRS)数据传输单元(Data Transfer Unit,DTU)模块的实时监测系统。系统通过现场控制终端采集通信电源设备的运行状态信息,经模拟数字(Analog to Digital,AD)转换模块处理后,由ARM核心控制芯片发送至无线模块,最终传输至远程监控中心。此外,设计一套应急预案,包括应急预案设计原则、组织机构与职责、应急分级、启动条件与工作流程以及保障措施等,以应对电网大停电带来的经济损失。通过技术保障、装备保障、人员保障,实现抢修工作的快速响应,缩短断电时间,有效减少经济损失,确保生产生活不受影响。
基金Post-Doctoral Innovative Projects of Shandong Province(No.200703072)the National Natural Science Foundation of China(No.50574053)
文摘In order to analyze the load carrying capacity of prestressed concrete box girders, failure behaviors of in-situ deteriorated continuous prestressed concrete box girders under loading are experimentally observed and a finite failure analysis method for predicting behaviors of box girders is developed. A degenerated solid shell element is used to simulate box girders and material nonlinearity is considered. Since pre-stressed concrete box girders usually have a large number of curve prestressed tendons, a type of combined element is presented to simulate the prestressed tendons of box girders, and then the number of elements can be significantly reduced. The analytical results are compared with full-scale failure test results. The comparison shows that the presented method can be effectively applied to the failure analysis of in-situ continuous prestressed concrete box girders, and it also shows that the studied old bridge still has enough load carrying capacity.
文摘Coal preparation is an integral part of the coal commodity supply chain. This stage of post-mining, pre-utilization beneficiation uses low-cost separation technologies to remove unwanted mineral matter and moisture which hinder the value of the coal product. Coal preparation plants typically employ several parallel circuits of cleaning and dewatering operations, with each circuit designed to optimally treat a specific size range of coal. Recent innovations in coal preparation have increased the efficiency and capac- ity of individual unit operations while reinforcing the standard parallel cleaning approach. This article, which describes the historical influences and state-of-the-art design for the various coal preparation unit operations, is organized to distinguish between coarse/intermediate coal cleaning and fine/ultrafine coal cleaning. Size reduction, screening, classification, cleaning, dewatering, waste disposal unit operations are particularly highlighted, with a special focus on the LI.S. design philosophy. Notable differences between the U.S. and international operations are described as appropriate.
基金Supported by the National Natural Science Foundation of China(No.69896242).
文摘Shared Memory (SM) switches are widely used for its high throughput, low delay and efficient use of memory. This paper compares the performance of two prominent switching schemes of SM packet switches: Cell-Based Switching (CBS) and Packet-Based Switching (PBS).Theoretical analysis is carried out to draw qualitative conclusion on the memory requirement,throughput and packet delay of the two schemes. Furthermore, simulations are carried out to get quantitative results of the performance comparison under various system load, traffic patterns,and memory sizes. Simulation results show that PBS has the advantage of shorter time delay while CBS has lower memory requirement and outperforms in throughput when the memory size is limited. The comparison can be used for tradeoff between performance and complexity in switch design.
