特高压1000kV电容式电压互感器研制

介绍了特高压电容式电压互感器研究内容,主要性能指标、结构设计及研制过程中出现的问题。     

CVT的新型阻尼装置

提出了电子式阻尼器的一种原理结线图。阐述了CVT的基本性能。     

Clearance and friction-induced dynamics of chain CVT drives

A continuously variable transmission (CVT) is an emerging automotive transmission technology that offers a continuum of gear ratios between desired limits. A chain CVT is a friction-limited drive as its performance and torque capacity rely significantly on the friction characteristic of the contact patch between the chain and the pulley. Moreover, such a CVT is susceptible to clearance formation due to assembly defects or extensive continual operation of the system, which further degrades its performance and leads to early wear and failure of the system. The present research focuses on developing models to understand the influence of clearance and different friction characteristics on the dynamic performance of a chain CVT drive. A detailed planar multibody model of a chain CVT is developed in order to accurately capture the dynamics characterized by the discrete structure of the chain, which causes polygonal excitations in the system. A suitable model for clearance between the chain links is embedded into this multibody model of the chain CVT. Friction between the chain link and the pulley sheaves is modeled using different mathematical models which account for different loading scenarios. The mathematical models, the computational scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of friction characteristics and clearance parameters on the dynamic performance, the axial force requirements, and the torque transmitting capacity of a chain CVT drive.     

光伏系统最大功率点跟踪控制算法的研究

介绍光伏建筑一体化(BIPV)系统及其特点,研究交流模块式BIPV系统最大功率点跟踪技术(MPPT)。针对BIPV系统中光伏组件的P-U曲线呈现多极值特性,提出多极值条件下光伏组件最大功率点跟踪控制算法。在Matlab/Simulink下进行建模与仿真,仿真结果验证了此算法的可行性。     

一起CVT电容分压器介损测试结果小于零的原因分析

本文分析了一起典型110 kV CVT整组电容介损测试中出现"-tanδ"的异常情况。导致这一问题出现的原因是测试中补偿电抗器L两端的保护用MOA未被拆除,从而使得部分信号电流经MOA支路直接流入大地,改变了信号电流的相位。进一步的理论分析结果表明,在对该结构类型的CVT进行整组电容介损测试时普遍存在这一问题,需引起试验人员的注意。为了避免保护用MOA对CVT整组电容介损测试造成不良影响,建议在测试过程中将其拆除。     

Friction Characteristics and Topography of Tribofilms from Anti-Wear Additives Applied to Metal V-Belt Type CVT Fluids

This study has investigated potential links between tribological performance and the morphology of tribofilms formed from anti-wear additives with application to metal V-belt pushing type continuously variable transmission fluids (B-CVTFs). The influence of metal–metal tribological properties of anti-wear additives was evaluated using a ball on plate tribometer, enabling friction and lubricant film formation to be monitored during reciprocating tests. Contact mode atomic force microscopy was utilised to investigate the nature of tribofilms at the nanometre scale. As a result, an additive formulation composed of hydrogen phosphite and over-based calcium sulphonate in a hydro-cracked mineral Group II base oil demonstrated a synergism with 8% higher friction coefficient and more stable film formation than the individual additive cases, providing a positive outcome for a B-CVTF. Tribofilm species produced by a chemical reaction between hydrogen phosphite and over-based calcium sulphonate were densely deposited on the wear scar to form a rougher surface, which may explain the higher friction observed.     

某雪橇车无级变速器调速特性分析与参数匹配

以国内某型雪橇车无级变速器为例,通过对其结构和工作原理的描述,建立了雪橇车V型胶带式无级变速器(Continuously Variable Transmission,CVT)主、从动轮的轴向力加压模型;选取主、从动弹簧的刚度及其初始压缩量4个参数作为无级变速器的主要设计参数,分析其调速特性与参数匹配;通过专用试验台的测试实验,验证了理论分析的正确性,同时测试结果也表明该CVT能够满足某型雪橇车的匹配要求。     

具有MPPT功能的光伏充电系统的研究

为了提高充电效率,该文在CVT充电器基础上提出了MPPT充电方案.该充电器不仅良好地实现了太阳电池的最大功率点跟踪,同时也附带实现了蓄电池过压保护等诸功能.实验结果表明,本方案较常规光伏系统所用的充电器具有良好的性能/价格比.     

500kV电容式电压互感器电压异常分析及处理

介绍电容式电压互感器的工作原理、结构及故障情况,结合CVT介损电容量测试数据、一次电压监测数据、角差比差试验数据,分析某变电站500kV电容式电压互感器电压异常的原因,并提出处理措施和建议。     

利用电压Y值分析法诊断CVT早期故障

介绍了一起CVT设备内部电容单元击穿造成电容量变化的典型缺陷,提出了电压Y值分析法。通过对基准CVT和被测CVT的一次电压值进行统计,再利用Y值分析法对统计数据进行计算分析,配合电容量计算,可以诊断出CVT故障发展的全过程,进而可以早期发现CVT故障,防止事故扩大。同时,还指出了电压Y值分析法可以用于CVT在线监测,对CVT运行状态进行实时的有效监控。