Fast Calculation Method of Energy Flow for Combined Electro-Thermal System and Its Application

In recent years, Combined electro-thermal system has developed rapidly. In order to provide the initial data for the analysis of the combined electro-thermal system, a practical energy flow calculation method for the combined electro-thermal system is proposed in this paper. Based on the detailed analysis of the topology structure of the heating network and its hydraulic and thermodynamic model, the forward-backward sweep method for the heat flow of the heating network is established, which is more suitable for the actual radial heating network. The electric and thermal coupling model for heating source, such as thermoelectric unit and electric boiler is established, and the heat flow of heating network and the power flow of power grid are calculated orderly, thus a fast calculation method for the combined electro-thermal system is formed. What’s more, a combined electro-thermal system with two-stage peak-shaving electric boiler is used as the example system. This paper validates the effectiveness and rapidity of this method through the example system, and analyzes the influence for the energy flow of combined electro-thermal system caused by the operating parameters such as the installation location of electric boiler, the outlet water temperature of heat source and the outlet flow rate, etc.

Model of Polysilicon Electro-thermal Micro Actuator and Research of Micro Scale Effect

A type of crank beam electro-thermal micro actuator was prescribed. Mechanical model of the actuator was established, and the static characteristic was analyzed.Comparing the theoretical analysis with experimental data, it is found that the thermodynamic character of material in micro actuator has a different variable regularity contrasted to that used in macro scale machines. It is the micro scale effect that results in the deviation between the simulating result and experimental results. The thermodynamic expression of polysilicon, which was fitted by means of the experimental data concerned, was used to modify the mechanical model. The modified model, in which the micro scale thermodynamic characteristic was considered, was more reasonable and could make the optimal design and control strategies analyzing the straight-line micro actuator more feasible.

ELECTRO-THERMAL EFFECTS AND DEFORMATION RESPONSE OF CARBON FIBER MAT CEMENT BEAMS

A carbon fiber mat is a sheet composed of intercrossing short carbon fibers,which has more stable and lower electrical resistivity compared with dispersed short carbon fiber mixed in cement.Thereby carbon fiber mat cement could exhibit obvious electro-thermal effect.When electrified,the temperature of composite structures made up of cement mortar and carbon fiber mat will rise rapidly.If the temperature field is not uniform,temperature difference will cause structures to deform,which can be used to adjust the deformation of structures.The temperature field and deformation response driven by the electro-thermal effects of a type of carbon fiber mat cement beams are studied.Firstly,the temperature and deformation responses are studied using theories of thermal conduction and elasticity.Secondly,experimental results are given to verify the theoretical solution.These two parts lay the foundation for temperature and deformation adjustment.

Microstructure and wear resistance of electro-thermal explosion sprayed stellite coating used for remanufacturing

Electro-thermal explosion directional spraying was used to prepare the stellite coating on substrate of the AISI 1045 steel. The morphologies of cross-section and worn scar, porosity, distribution of elements, micro- hardness and wear resistance of the coating were determined by means of SEM, EDAX, micro-hardness tester and sliding wear tester. Because of the compact construction, good bonding and high hardness, the coating is characterized by good wear resistance. The results show that the mainly failure mode of the stellite coating is micro- plowing.

STUDY ON THE THERAPEUTIC EFFECT AND MECHANISMS OF ELECTRO-THERMAL NEEDLING FOR TREATMENT OF VULVAL LEUKOPLASIA

In the present paper,444 patients with vulvar leukoplasia were treated by selectingacupoints in the local area and along the meridian plus Qugu（CV 2）and Huiyin（CV 1）and usingelectro-thermal needling.The total effective rate was up to 100.0％and the cure rate 87.3％.Theelectro-thermal effect directly acted on the affected area but strengthened the immunologic function ofthe whole body and raised the content of serum copper.

High-temperature corrosion-resistance performance of electro-thermal explosion spraying coating

As a new spraying technology used in the remanufacturing engineering, electro-thermal explosion spraying holds a lot of advantages. Electro-thermal explosion spraying coating aliquation phenomena are reduced and non-crystal, micro-crystal and millimicron-crystal and other microstructure are formed. The corrosion-resistance ability of electro-thermal explosion spraying coating in high temperature environment was surveyed respectively. SEM equipped with EDS was employed to analyze the microstructure of spraying coating before and after corrosion. The corrosion-resistance mechanism of the spraying coating was discussed.

ELECTRO-THERMAL MOXIBUSTION ON ACUPOINTS FOR TREATMENT OF 98 CASES OF SCIATICA

98 patients with sciatica are treated.by stimubting acupoints using a self-made electro-thermal moxibustion instrument.Results show that 82 cases arecured,8 improved and 5 effective,with the total effective rate of 96.9％.The temperature relesed from this instrument is adjustable.The electro-thermal moxibustion therapy is short in treatment duration and rapid in taking effect.Ithas no needling-induced pain and no side-effects,and is accepted preferably by patients.

Microstructure and Deposition Mechanism of C/SiCN Composites Prepared by Rapid Electro-thermal Pyrolysis CVD

Carbon fiber-reinforced silicon carbonitride ceramic matrix composites （C/SiCN） were prepared by rapid electro-thermal pyrolysis CVD using liquid polymer hexamethyldisilazane （HMDS, （CH3）3SiNHSi（CH3）3） as precursor. Microstructure morphology and production technique of C/SiCN composites were investigated. Scanning electron microscopy and transmission electron microscopy were respectively employed to characterize microstructures of the as-received C/SiCN composites samples. The high temperature pyrolysis of HMDS results in destruction of molecular chain, fracture of bonds, as well as liquid-gas-solid conversion from polymer to ceramic. Microstructures observation indicates that there is a high degree of coalescence between SiCN matrix and C fiber. The deposition model of liquid precursor electro-thermal pyrolysis CVD is different from that of gas precursor isothermal chemical vapor infiltration. Rapid liquid flow and slow gas diffusion are key factors for the difference of two methods. Preparation of rapid electro-thermal pyrolysis CVD consists of four steps including liquid polymer infiltration, polymer pyrolysis, rapid deposition of pyrolyzed substances and rapid densification, respectively.

THE FUZZY NUMERICAL VALUE SIMULATION OF NANOMETER ELECTRO-THERMAL IN HOT-WORKING

The fuzzy numerical value analysis method is adopted for the first time, which solves the problem of nanometer electro-thermal in filming process, The key technique is embodied by controlling the time distribution, temperature and press in the filming process. The concrete technique of filming is showed by establishing the fuzzy mumbership function of above three indexes, which improves the precision of the materials of nanometer electro-thermal in hot-working. At the same time, the principles of the fuzzy relationship mapping inversion （FRMI） is put forward, Therefore, the standardization and continuity can be met.

Design and Fabrication of 2-DOF Micromirror Array Based on Electro-Thermal Actuators

With surface- and bulk-micromachining, an 8 × 8 mirrors array is designed, fabricated and tested, which is based on electro-thermal actuators and can be addressed individually. The micromirror is square shaped, 4-corner-actuated. Its dimension is 200 μm × 200 μm. The substrate below it is caved away to ensure a tilt at an angle as large as possible. To protect the etch-sensitive features on the front side of the wafer undamaged during wet deep silicon etch on the backside, the wax protective coating process is used. Mirror actuated by powering an alternative pair of heaters will tilt in 2-DOF. If its 4 cantilevers/heaters are powered synchronously, it will move in a piston mode. The effective arrays are more than 80% out of the three finished wafers. When the ramp voltage frequency applied to a pair of neighboring cantilevers is 5 Hz at 10 V, the average tilting angle can be ± 8°.

Study on Approach of Static Security Assessment Accounting for Electro-thermal Coupling

A static security assessment approach considering electro-thermal coupling of transmission lines is proposed in this paper. Combined with the dynamic thermal rating technology and energy forecasting, the approach can track both the electrical variables and transmission lines’ temperature varying trajectory under anticipated contingencies. Accordingly, it identifies the serious contingencies by transmission lines’ temperature violation rather than its power flow, in this case the time margin of temperature rising under each serious contingency can be provided to operators as warning information and some unnecessary security control can also be avoided. Finally, numerical simulations are carried out to testify the validity of the proposed approach.

Synthesis of Ti₃SiC₂-Bicarbide Based Ceramic by Electro-Thermal Explosion

A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and mechanical properties. Furthermore, it shows a damage tolerance capability and oxidation resistance. In this work, we have synthesized Ti3SiC2 by electro-thermal explosion chemical reaction (ETE) with high current density (900 Amperes/a.u) followed by uniaxial pressure. The structural properties of the as-prepared materials are studied by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The chemical cartography, imaging and electronic properties are investigated using Ultra-STEM and electron high energy loss resolution spectroscopy (EELS) techniques, respectively. The surface of Ti3SiC2 is characterized by means of X-ray photoelectron spectroscopy (XPS). High resolution C 1s, Si 2p, Ti 2p, Ti 3s core level spectra are explained in terms of crystallographic and electronic structure. Valence band spectrum is performed to confirm the validity of the theoretical calculations.

A study on temperature monitoring method for inverter IGBT based on memory recurrent neural network

The power module of the Insulated Gate Bipolar Transistor(IGBT)is the core component of the traction transmission system of high-speed trains.The module's junction temperature is a critical factor in determining device reliability.Existing temperature monitoring methods based on the electro-thermal coupling model have limitations,such as ignoring device interactions and high computational complexity.To address these issues,an analysis of the parameters influencing IGBT failure is conducted,and a temperature monitoring method based on the Macro-Micro Attention Long Short-Term Memory(MMALSTM)recursive neural network is proposed,which takes the forward voltage drop and collector current as features.Compared with the traditional electricalthermal coupling model method,it requires fewer monitoring parameters and eliminates the complex loss calculation and equivalent thermal resistance network establishment process.The simulation model of a highspeed train traction system has been established to explore the accuracy and efficiency of MMALSTM-based prediction methods for IGBT power module junction temperature.The simulation outcomes,which deviate only 3.2% from the theoretical calculation results of the electric-thermal coupling model,confirm the reliability of this approach for predicting the temperature of IGBT power modules.

光栅MOEMS加速度计温度特性

由于硅微机械加速度计受温度影响,导致硅弹性模量和热膨胀系数发生变化,造成微光机电系统(MOEMS)加速度计标度因数漂移、测量稳定性下降等问题。首先,采用COMSOL软件对光栅MOEMS加速度计微机械结构部分进行了温度特性仿真,分析了硅弹性模量温度系数和热膨胀系数对光栅MOEMS加速度计微机械结构标度因数和零位的影响。其次,设计了温控精度达0.1℃的温度控制系统,并利用该系统对加速度计进行温度控制。最后,对光栅泰伯效应MOEMS加速度计温度特性展开测试,结果表明,加速度计的标度因数随温度升高而增大,零偏稳定性随温度的升高而降低,加速度计标度因数温度系数为0.30 V·g^(-1)·℃^(-1),零偏稳定性温度系数为-7.78μg/℃,其变化趋势与仿真结果一致。这为实现全温范围下高精度MOEMS加速度计奠定了基础。

基于TSV的三维集成系统电热耦合仿真设计

三维集成系统利用垂直堆叠技术,实现高性能与低功耗,其中硅通孔(TSV)技术是三维互连成功实施的关键。TSV技术缩短互连距离,提升信号传输效率和电磁兼容性,但同时引发电热耦合问题,威胁三维集成电路性能的进一步提升。综述了基于TSV的三维集成电路中电热耦合现象的仿真设计进展,详细介绍了电气和热仿真设计方法,并探究了电热耦合问题的潜在影响及缓解策略。为理解和应对三维集成系统中的电热耦合挑战提供了系统的分析,并对未来研究方向提供了指导。

储能用锂离子电池电热耦合模型研究进展

高精度的电池模型是提升电池管理系统工作效率的关键,对于实现电池系统状态评估、寿命预测和健康运行具有重要意义。归纳和总结锂离子电池性能、温度非均匀特性和锂离子电池电热耦合模型构建方法及存在的问题。目前尚缺乏针对大规模储能电池全生命周期、复杂结构和环境因素条件下电热互动机制研究。基于经验方程和基于电池内部机理的电池热分析模型,存在计算速度慢、精度低和通用性差等问题。基于数据驱动的模型是一种更加高效的电池热学模型构建方法。在电池组层面,大多基于串并联方式和电池状态参数构建模型,不能准确模拟电流和环境温度非均匀条件下电池动态特性。依据储能电池系统复杂结构和环境特点,提高模型计算速度和精度成为下一步研究方向。

计及综合需求响应的电热集成系统优化运行

针对我国“三北”地区供暖季弃风严重问题,提出一种计及综合需求响应(CDR)的电热集成系统(IETS)优化调度策略。基于电量电价弹性矩阵构建实时电价需求响应模型以引导用户错峰时移用电;考虑到热用户对供热温度感知的模糊性,将其作为热能需求响应参与调度,分析并阐述电热需求响应促进风电消纳的机理;通过多场景分析刻画新能源预测的不确定性,计及系统安全运行约束,以系统总运行成本最小优化求解日前调度决策与旋转备用容量安排。最后,通过典型算例对比不同模式下的调度策略,验证了提出的计及CDR的优化调度策略能够开阔风电上网空间和提高系统的经济性。

计及热惯性的热电联产虚拟电厂韧性提升策略

日益频繁的极端天气给电热耦合系统造成的影响愈发严重。韧性是衡量系统抵御极端事件、减少故障影响并快速恢复的核心指标。为提升电热耦合系统抵御极端灾害的能力,提出一种考虑热惯性的热电联产虚拟电厂(combined heat and power-virtual power plant,CHP-VPP)两阶段三层韧性提升策略。第一阶段以联络开关成本最小为目标,基于最小生成树理论对系统进行重构;第二阶段以运行成本最小为目标,基于分布鲁棒优化理论制定最恶劣的故障场景下的最优决策。采用列与约束生成算法进行迭代求解。基于IEEE 33节点电力系统+6节点供热系统构建CHP-VPP测试系统,仿真结果表明,所提出的方法可有效提升CHP-VPP应对极端灾害的韧性。

Spark plasma sintering ofα/β-SiAlON ceramic end mill rods:Electro-thermal simulation,microstructure,mechanical properties,and machining performance

Spark plasma sintering(SPS)is a highly efficient method for the preparation ofα/β-SiAlON ceramics.However,the rapid preparation of large-scaleα/β-SiAlON ceramic components with reliable mechanical properties is difficult via SPS due to their near-insulating properties.In this study,high-performanceα/β-SiAlON ceramic end mill rods with large aspect ratios were successfully prepared via SPS.Two different types of sintering processes(namely vertical-round-rod(VRR)and horizontal-square-rod(HSR)processes)were developed,and their effects on the phase composition,microstructure,mechanical properties,and machining performance of theα/β-SiAlON ceramic end mill rods were studied.The electric and temperature field distributions during sintering were studied through an electro–thermal simulation.The simulated and experimental temperature distributions are in good agreement.In contrast to VRR samples,HSR samples with a small axial size show a uniform temperature distribution and satisfactory microstructures within a certain range of dimensions as well as the expected phase composition;furthermore,elongatedβ-SiAlON grains are preferentially oriented in the direction perpendicular to the sintering pressure direction.As a result,the HSR samples exhibit better mechanical properties and machining performance than the VRR samples.

电—热综合能源系统多目标优化

为了提高能源利用效率与实现能源清洁供应,提出了一种电-热综合能源系统多目标最优能流计算方法。首先,以系统运行成本和污染物排放最优为目标,考虑系统运行安全约束,建立电-热综合能源系统多目标最优能流模型。然后,采用改进的非劣排序遗传算法求解多目标优化模型,求取帕累托最优解集。电网9节点和热网32节点联合算例仿真结果表明,所提方法能够有效考虑系统经济性、环保性以及各类运行约束,为运行人员提供更多的决策方案。