Grasshopper optimization algorithm for optimal load frequency control considering Predictive Functional Modified PID controller in restructured multi-resource multi-area power system with Redox Flow Battery units

Load frequency control (LFC) is a well-established issue in design and operation of power systems considering to the extension, restructuring, and complexity of the interconnected power systems and also the emergence utilization of renewable energy resources. This paper studies the frequency control of multi-area multi-source power system based on the importance of the LFC in the stability of the power system which includes various generation units of thermal, hydroelectric, wind, natural gas and diesel under the restructured environment. In this system, non-linear physical constraints, governor dead band (GDB) and generation rate constraint (GRC) are considered. In this paper, a new Predictive Functional Modified PID (PFMPID) controller is proposed that the effectiveness of this controller is verified compared to the traditional one. In order to optimize and demonstrate the superiority of the proposed control method, Grasshopper Optimization Algorithm (GOA) is proposed as a suitable solution. To further improve the performance of the under study system, the use of the Redox Flow Battery (RFB) energy storage unit has also been proposed. Since the operation evaluation of the proposed process is necessary in different system conditions, the performance of the proposed method is studied under various disturbances and simulation results are presented.     

Al-Si7-Mg消失模振动凝固组织半固态热处理

利用消失模铸造振动凝固技术,得到Al-Si7-Mg合金的近等轴晶组织。在此基础上研究了580℃不同时间保温半固态等温热处理(SSIT)组织中α-Al晶体的形貌与尺寸变化。结果表明:合金580℃保温1h,得到α晶粒的等积圆直径在50~150μm的分布比例达85%,α晶粒圆度均值1.41。通过凝固动力学和热力学分析,得出半固态热处理过程中,低熔点的三元共晶和二元共晶相首先熔化,并随着溶质元素扩散速度的增加,液相不断增多,α晶体形状大小不断改变;当液相率达到平衡之后,α晶粒在界面张力的作用下,不断圆整球化,合并长大。半固态热处理α枝晶演变形式明显不同于等轴晶演变过程。     

发动机缸体模具设计

发动机缸体作为发动机中最重要的部件之一,其尺寸较大、结构复杂、壁厚较薄且很不均匀(最薄处仅为3～5mm),同时其工艺范围狭窄,影响因素众多,是典型难以成形的复杂铸件,因此比较适合于采用消失模铸造生产.在发动机缸体的模具设计中,考虑产品的特点和后续生产的便利性,结合消失模模具本身的特点,设计出结构合理的模具,有利于提高产品的合格率和综合性能.     

A novel optimized hybrid fuzzy logic intelligent PID controller for an interconnected multi-area power system with physical constraints and boiler dynamics

In the fast developing world nowadays, load frequency control (LFC) is considered to be a most significant role for providing the power supply with good quality in the power system. To deliver a reliable power, LFC system requires highly competent and intelligent control technique. Hence, in this article, a novel hybrid fuzzy logic intelligent proportional-integral-derivative (FLiPID) controller has been proposed for LFC of interconnected multi-area power systems. A four-area interconnected thermal power system incorporated with physical constraints and boiler dynamics is considered and the adjustable parameters of the FLiPID controller are optimized using particle swarm optimization (PSO) scheme employing an integral square error (ISE) criterion. The proposed method has been established to enhance the power system performances as well as to reduce the oscillations of uncertainties due to variations in the system parameters and load perturbations. The supremacy of the suggested method is demonstrated by comparing the simulation results with some recently reported heuristic methods such as fuzzy logic proportional-integral (FLPI) and intelligent proportional-integral-derivative (PID) controllers for the same electrical power system. the investigations showed that the FLiPID controller provides a better dynamic performance and outperform compared to the other approaches in terms of the settling time, and minimum undershoots of the frequency as well as tie-line power flow deviations following a perturbation, in addition to perform appropriate settlement of integral absolute error (IAE). Finally, the sensitivity analysis of the plant is inspected by varying the system parameters and operating load conditions from their nominal values. It is observed that the suggested controller based optimization algorithm is robust and perform satisfactorily with the variations in operating load condition, system parameters and load pattern.     

铝合金消失模铸造涂料自动流平系统设计

本文介绍了采用消失模工艺生产某型铝合金变速器壳体时,通过简单的机械装置来代替人工操作的涂料自动流平系统。该系统降低浸涂工序中模型涂料流平操作的劳动强度,提高了生产效率。     

A robust adaptive load frequency control for micro-grids

The goal of this study is to introduce a novel robust load frequency control (LFC) strategy for micro-grid(s) (MG(s)) in islanded mode operation. Admittedly, power generators in MG(s) cannot supply steady electric power output and sometimes cause unbalance between supply and demand. Battery energy storage system (BESS) is one of the effective solutions to these problems. Due to the high cost of the BESS, a new idea of Vehicle-to-Grid (V2G) is that a battery of Electric-Vehicle (EV) can be applied as a tantamount large-scale BESS in MG(s). As a result, a new robust control strategy for an islanded micro-grid (MG) is introduced that can consider electric vehicles׳ (EV(s)) effect. Moreover, in this paper, a new combination of the General Type II Fuzzy Logic Sets (GT2FLS) and the Modified Harmony Search Algorithm (MHSA) technique is applied for adaptive tuning of proportional-integral (PI) controller. Implementing General Type II Fuzzy Systems is computationally expensive. However, using a recently introduced α-plane representation, GT2FLS can be seen as a composition of several Interval Type II Fuzzy Logic Systems (IT2FLS) with a corresponding level of α for each. Real-data from an offshore wind farm in Sweden and solar radiation data in Aberdeen (United Kingdom) was used in order to examine the performance of the proposed novel controller. A comparison is made between the achieved results of Optimal Fuzzy-PI (OFPI) controller and those of Optimal Interval Type II Fuzzy-PI (IT2FPI) controller, which are of most recent advances in the area at hand. The Simulation results prove the successfulness and effectiveness of the proposed controller.     

镁合金真空低压消失模铸造充型能力的研究

利用自主开发的真空低压消失模铸造技术及其装备研究了AZ91D镁合金在不同工艺参数条件下的成型能力，成功地浇注出了电机外壳、排气管等复杂的镁合金铸件，试验研究表明，这种新的消失模铸造工艺大大提高了镁合金的充型能力，消除了重力下消失模铸造美合金充型能力差，易形成浇不足和冷隔缺陷的缺点。     

不同排气塞数量下的泡沫模样的射料充填数值模拟

建立了欧拉/拉格朗日离散颗粒模型,采用数值模拟方法,研究消失模铸造泡沫珠粒射料充填过程中稠密气/固两相流动的流体动力特性。泡沫珠粒的运动与气相压力分布密切相关,泡沫珠粒充填过程中在排气塞附近区域形成型腔内外压力差,是珠粒充填的动力。在其他条件相同时,对3种不同排气条件下的射料充填过程进行了数值模拟,结果表明,排气不畅时射料充填过程持续时间最长,易在型腔内的高压区出现充填不密实的现象。     

含风电的多域互联电力系统负荷频率控制方法

为确保风机参与调整系统负荷频率,建立了三区域含风力发电的互联电力系统负荷频率控制模型;同时,为抑制整个系统内部参数的变化、风能波动及负荷扰动所造成的负荷频率波动,又设计出一个分散的滑模控制器并用于仿真分析,当整个系统在进入滑动模态后,对外界的参数变化具有时不变性。仿真结果表明,所设计的滑模控制器比传统的控制器响应更快、超调量小,有效抑制了负荷频率波动,且当考虑发电机变化率约束条件时,所设计的滑模控制器仍能有效控制系统稳定。     

脉宽对不同密度介质中传播的超短脉冲特性的影响

利用使用预估校正（PC）-时域有限差分（FDTD）法求得的全波Maxwell-Bloch方程组的数值解,研究脉宽对在不同密度的V型三能级介质中传播的飞秒超短激光脉冲特性的影响。结果表明,不同原子密度情况下,脉宽改变对脉冲传播特性的影响是不同的。当超短脉冲在原子密度较小的稀疏介质中传播时,脉冲不易发生分裂;当脉冲未分裂时...