系统电参数及其对轴承电流的影响

本文考察了在脉宽调制（PWM）电压源逆变器下运行时交流电动机轴电压以及所引起的轴承电流。本文回顾了引起轴电压和轴承电流的轴承和电动机的电气特性。简单回顾了以前所做的工作，其中包括了对轴承电流所作电气分析的系统模型。以姐妹篇文章的工作为基础，放电侵蚀（EDM）倾向由一个设计方程决定，该方程是各系统部件的一个函数。本文叙述了有关的电机参数及其公式，计算了从5至1000马力电机的值。用实验的方法评估了系统元件对轴电压和轴承电流的影响，其结果可与理论值相比拟。最后，文章将叙述轴电压和轴承电流问题一个解决办法的定量结果。

智能电参数测控系统的设计

基于ATmega16、GPRS/GSM、锁相倍频技术、电力参数测量算法、无功功率动态补偿算法提出了集电能参数遥测、遥控、无功补偿于一体的测控系统设计方案。系统通过ADS7864芯片对三相电压、电流信号进行同步采样,在对采样信号进行复序列离散傅里叶变换(DFT)处理后,即可计算出有功、无功、功率因数等电参量,并据此电参量实现安全判定及无功功率型动态补偿,从而有效地克服了功率因数型无功补偿难以兼顾线路系统稳定与补偿效果的缺陷。实验和现场调试结果验证了测控系统的有效性。

交流接触器触头电参数测试系统

介绍了一种用微机实现的交流接触器触头电参数测试系统 ,分析了交流接触器触头的接触电阻和温升的测量原理 ,简述了测试系统的硬件结构和软件流程。该系统根据被测信号的特点进行数据采集、数据处理和数据显示 ,实现了操作的可视化和简易化。

一种基于专用DSP芯片的三相电参数测量系统

介绍了一种使用专用DSP芯片AT73C50 1、AT73C50 0的三相电参数测量系统 .该系统可以测量三相电的功率、功率因数、相电压、相电流、电网频率 ,提供了测量三相电参数的一种新颖、简便的实现方法 .

测试系统继电器电阻值异常的工程学分析及解决

介绍了对于测试系统接触测试项目出现异常所做的分析,最终定位问题出现在测试系统继电器的电阻值的异常,经过分析和试验,其异常的原因归结为测试系统针对特定结构的被测产品因为考虑不周而使悬空的测试线路带有超过允许范围的电荷,导致在之后的继电器开关过程中对触点造成伤害。文中提出了解决方案并通过实践验证解决方案的可行性。

脉冲等离子体推力器实验系统

本文介绍了一种用于脉冲等离子体推力器(PPT)的新型实验系统的构成、设计思路、可实验内容、运行结果等内容。该系统包括真空系统、真空舱、深冷吸附系统、真空系统电控系统、μN量级微推力测量系统、电参数测量系统等六部分。本实验系统具有多功能、高性能的特点,为PPT的实验研究建立起良好的物质平台。经过多次、多条件的点火实验,其运行结果证明了实验系统设计思路的正确性,为今后设计制造同类实验设备提供了可靠的经验。

Working Condition Real-Time Monitoring Model of Lithium Ion Batteries Based on Distributed Parameter System and Single Particle Model

Lithium ion batteries are complicated distributed parameter systems that can be described preferably by partial differential equations and a field theory. To reduce the solution difficulty and the calculation amount, if a distributed parameter system is described by ordinary differential equations （ODE） during the analysis and the design of distributed parameter system, the reliability of the system description will be reduced, and the systemic errors will be introduced. Studies on working condition real-time monitoring can improve the security because the rechargeable LIBs are widely used in many electronic systems and electromechanical equipment. Single particle model （SPM） is the simplification of LIB under some approximations, and can estimate the working parameters of a LIB at the faster simulation speed. A LIB modelling algorithm based on PDEs and SPM is proposed to monitor the working condition of LIBs in real time. Although the lithium ion concentration is an unmeasurable distributed parameter in the anode of LIB, the working condition monitoring model can track the real time lithium ion concentration in the anode of LIB, and calculate the residual which is the difference between the ideal data and the measured data. A fault alarm can be triggered when the residual is beyond the preset threshold. A simulation example verifies that the effectiveness and the accuracy of the working condition real-time monitoring model of LIB based on PDEs and SPM.

Online SOC estimation based on modified covariance extended Kalman filter for lithium batteries of electric vehicles

To offset the defect of the traditional state of charge(SOC)estimation algorithm of lithium battery for electric vehicle and considering the complex working conditions of lithium batteries,an online SOC estimation algorithm is proposed by combining the online parameter identification method and the modified covariance extended Kalman filter(MVEKF)algorithm.Based on the parameters identified on line with the multiple forgetting factors recursive least squares methods,the newly-established algorithm recalculates the covariance in the iterative process with the modified estimation and updates the process gain which is used for the next state estimation to decrease errors of the filter.Experiments including constant pulse discharging and the dynamic stress test(DST)demonstrate that compared with the EKF algorithm,the MVEKF algorithm produces fewer estimation errors and can reduce the errors to 5%at most under the complex charging and discharging conditions of batteries.In the charging process under the DST condition,the EKF produces a larger deviation and lacks stability,while the MVEKF algorithm can estimate SOC stably and has a strong robustness.Therefore,the established MVEKF algorithm is suitable for complex and changeable working conditions of batteries for electric vehicles.

Numerical simulation of deepwater deployment for offshore structures with deploying cables

Deepwater deployment of offshore structures in different sea states was investigated. The whole deployment system was modeled as a lumped mass model, and discretization scheme for cable geometry and methodology for calculating the internal and external force acting on deploying cable were presented. The deployment model suitable for the time-varying length of deploying cable was specified. The free-surface flow fields together with the ship motions were used to calculate dynamic tension in the deploying cable during deployment of the structure. The deployment of deep sea mining system which was a typical subsea working system was employed. Based on lumped mass analysis model and parameters of deep sea mining system, numerical simulations were performed, and dynamic load and dynamic amplification factor(DAF) with different cable parameters, deploying velocities and sea states were obtained. It is shown that cable parameters and amplitudes of ocean waves can significantly influence the dynamic load and DAF, and the time-varying natural period of deploying system is a dominant factor, while the effect of deploying velocity is not obvious.

Influence of Pre-injection Control Parameters on Main-injection Fuel Quantity for an Electronically Controlled Double-valve Fuel Injection System of Diesel Engine

A simulation model of an electronically controlled two solenoid valve fuel injection system for a diesel engine is established in the AMESim environment.The accuracy of the model is validated through comparison with experimental data.The influence of pre-injection control parameters on main-injection quantity under different control modes is analyzed.In the spill control valve mode,main-injection fuel quantity decreases gradually and then reaches a stable level because of the increase in multi-injection dwell time.In the needle control valve mode,main-injection fuel quantity increases with rising multi-injection dwell time;this effect becomes more obvious at high-speed revolutions and large main-injection pulse widths.Pre-injection pulse width has no obvious influence on main-injection quantity under the two control modes;the variation in main-injection quantity is in the range of 1 mm3.

Adaptive Robust Control of Multi-Machine Power Systems with Control Time Delay

The adaptive H_∞ control problem of multi-machine power system in the case of disturbances and uncertain parameters is discussed,based on a Hamiltonian model.Considered the effect of time delay during control and transmission,a Hamilton model with control time delay is established.Lyapunov-Krasovskii function is selected,and a controller which makes the system asymptotically stable is got.The controller not only achieves the stability control for nonlinear systems with time delay,but also has the ability to suppress the external disturbances and adaptive ability to system parameter perturbation.The simulation results show the effect of the controller.

Virtual test system for permanent-magnet DC motor

In order to obtain the primary parameters and operating characteristics of a DC motor without directly measuring its torque and rational speed, it is proposed to use a PC and a data acquisition card to acquire both the dynamic and static data of armature current to establish the performance of a DC permanent magnet motor. The accuracy and validity of this virtual test system proposed were verified by comparing the measurements made with the system proposed with the measurements made with conventional torque meters. It is concluded from the results of comparison that from the mathematic model established for the DC permant magnet motors, both major parameters and operating characteristics can be directly established for the DC motors without measuring their torques and rotational speed, a perfect on line measurement and test system has been established for the DC permanent magnet motors using the theory of virtual test system. The system proposed features shorter test time, higher efficiency and lower cost.

Design and Performance Analysis of Micro Proton Exchange Membrane Fuel Cells

This study describes a novel micro proton exchange membrane fuel cell(PEMFC)(active area,2.5 cm2).The flow field plate is manufactured by applying micro-electromechanical systems(MEMS) technology to silicon substrates to etch flow channels without a gold-coating.Therefore,this investigation used MEMS technology for fabrication of a flow field plate and presents a novel fabrication procedure.Various operating parameters,such as fuel temperature and fuel stoichiometric flow rate,are tested to optimize micro PEMFC performance.A single micro PEMFC using MEMS technology reveals the ideal performance of the proposed fuel cell.The optimal power density approaches 232.75 mW·cm-1 when the fuel cell is operated at ambient condition with humidified,heated fuel.

A measurement system of magnetism parameters for motion control

Magnetism parameters vary with the position and the speed of electromagnetic actuator's motion parts.The measurement unit presented in the paper can be applied to get the position and the speed feedback information from the measurement of electromagnetism parameters,and can constitute the untouched feedback sensing unit in the closed-loop motion control,and it adapts to the diversified feedback control of electromagnetic actuator.The digital miniaturization meter,based on MSP430 single chip processor,which can do the multi-purpose measurement of Φ & B through the menu selection,can be used for the electromagnetic actuator's performance evaluation and improvement,and also the online quality control in production process.Both real-time data graph and data table can be displayed in the meter.The paper presents the system's structure,describes the principle,discusses the working modes,and shows the software flowchart and the measuring results.

Research on the adjustment model of ventilation characteristic parameters based on integrated method of circuit and path

Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult to obtain accurate results. In order to check the ventilation characteristic parameters of mines more accurately, the integrated method of circuit and path is adopted to overcome the drawbacks caused by the traditional path method or circuit method in the digital debugging process of ventilation system, which can improve the large local error or the inconsistency between the airflow direction and the actual situation caused by inaccuracy of the ventilation characteristic parameters or checking in the ventilation network solution. The results show that this method can effectively reduce the local error and prevent the pseudo-airflow reversal phenomenon; in addition, the solution results are consistent with the actual situation of mines, and the effect is obvious.

Optimal Power Flow Solution Using Particle Swarm Optimization Technique with Global-Local Best Parameters

This paper proposes an efficient method for optimal power flow solution （OPF） using particle swarm optimization （PSO） technique. The objective of the proposed method is to find the steady state operation point in a power system which minimizes the fuel cost, while maintaining an acceptable system performance in terms of limits on generator power, line flow limits and voltage limits. In order to improvise the performance of the conventional PSO （cPSO）, the fine tuning parameters- the inertia weight and acceleration coefficients are formulated in terms of global-local best values of the objective function. These global-local best inertia weight （GLBestlW） and global-local best acceleration coefficient （GLBestAC） are incorporated into PSO in order to compute the optimal power flow solution. The proposed method has been tested on the standard IEEE 30 bus test system to prove its efficacy. The results are compared with those obtained through cPSO. It is observed that the proposed algorithm is computationally faster, in terms of the number of load flows executed and provides better results than the conventional heuristic techniques.

New Change of Technical Indicators System of Watt-Hour Meters

There is an imperfection in the accuracy indicators system and the technical parameters system in IEC standards 62053-21 implemented for watt-hour meters currently. This article quoted some parts of OIML MI-003 and R46 contents to provide a reference of the integrity comparison between the accuracy system and technical parameter system. The comparison result shows that the watt-hour meter accuracy technical indicators system of OIML R46 is more integrated. First reason is that it determines all the accuracy （basic error） defining rules just by using the technical parameter I efficiently; secondly, it can solve the contradiction that no error regulation of the range from starting current to minimum current in the process of providing, handing over and checking watt-hour meter products＇ qualities efficiently. Please pay close attention to the R46 official version which will be released soon, as it is still in the Committee Draft （CD6） stage currently.

Power Flow Calculation Method of Large Shipboard Power System

The effect of line voltage drop is considered larger on loads, especially on asynchronous motor, transformers and other non-linear load parameters in power system of large ships. A novel power flow method based on improved node voltage method is proposed, and a typical ship power system, which has 2 power stations and 10 nodes, with closed-loop design but open-loop operation, is taken as an example. Simulation results show that the improved power flow calculation method has achieved higher accuracy and better convergence.

Electric Parameter Measurement System Based on Virtual Instrument

In this paper, virtual instnnnent technology is applied in the development of an electric parameter measta＇ement system for mobile power stations. Virtual inset technology is used to lmasure and analyze electric parameters of mobile power stations. The whole measurement system is mmpmed of computer, data acquisition card and LabView virtual instnnnent platform. It can be used to monitor, record, and analyze electric parameters of sinusoidal alternating ciroait These parameters include voltage, effective value of ctaxent, phase differences, power, and etc. Experimental results show that this virtual measuring device satisfy the requirement of mobile power station montoring anti dynamic property analysis. Hardware and software design of the system will be discussed in detail.