A method of power measurement under nonsinusoidal periodic signals

In power system,traditional method of nonsinusoidal power measurement is not feasible for containing non integer harmonics condition. A method of power measurement based on Prony algorithm is presented. At first, identify all modes of integer and non interger harmonics from voltage and current signals, using Prony method. Futher more, calculate active and reactive power in each harmonics frequency, using the modes of harmonics. Based on the defination of IEEE active power, a expression of Budeanu power is given in non integer harmonics condition. At last, active and reactive power of energy gird are calculated. The results of simulation prove that this method is feasibility. The method of power measurement based on Prony algorithm has high precision, especially for non integer harmonics condition.     

电动缸性能参数测试系统设计

针对现有的电动缸测试系统和测试方法不能满足电动缸产品出厂参数快速测量的问题,研发了一套以PC机作为上位机,雷赛DMC5480运动控制卡作为核心控制器,高精度磁栅尺为检测装置的电动缸性能参数测试系统。根据测试需求设计了开放式电动缸测试系统、测试方法和功能测试模块;结合数据测量装置,基于VB和API函数研发了开放式电动缸自动测试系统软件平台,包括电动缸的位置精度、回程误差、重复定位精度、误差分析与补偿及跟随误差测试等功能模块。该测试系统成功应用于某公司电动缸出厂参数快速测量。     

Simulation analysis of control strategy for electric power steering system

The mathematical model of the electric power steering (EPS) system is developed,and control strategy is designed by the way of frequency analysis using Bode diagram,on a basis of steering feel expression．A complete model used for analysis of automotive steering characteristic,with four tire and three freedom vehicle models is built．In order to meet optimal goals,including steering agility,return ability and steering effort requirements of drivers, the rule of controller parameter values under the condition of different speeds and steering torques is concluded through numerous simulation tests．     

Analysis of power frequency electric field distortion effect on uniform electric field

The electric field sensor for the measurement of electric field in the space where the sensor probe will cause distortion in the vicinity,so it will affect the measurement of electric field accuracy. This paper uses the separation of variables method to calculate the electric field distortion caused by spherical sensor probe in uniform electric field,and detailed analysis of the 10 kV voltage,the spherical probe size,electrode material and the measuring electrode pole coupling caused the impact of electric field distortion. According to the induced voltage of sensor and the linear relationship between electric field strength,using the impact factor matrix to correct the electric field distortion. The result shows that the vicinity of the probe and the primary measuring electrodes and sub-electrodes measuring produce more serious distortion in the uniform electric field. The average distortion rate is more than 27%;however,after the impact factor matrix is used to correct the electric field distortion,the average error is about 4.47%. By analysis of the measurement of the electric field distortion with the spherical probe of sensor,it is conducive to reduce the impact of distortion on the electric field measurement and to improve the accuracy of field measurement.     

Powertrain parameter design for the electric vehicle with taking the energy consumption of air conditioner into consideration

On the basis of considering the influence of air conditioner on vehicle performance,the parameter determination of the power train composed of a battery,a traction motor and a two-speed transmission of an electric car is carried out. To ensure the economy of operation,a shifting strategy with a principle which emphasizes the high work efficiency of the power train is drawn up and the gear ratios are corrected aiming at the least energy cost over the drive cycle. The simulation results indicate that the designed parameters meet the requirements moderately and the driving range is extended by 5.28% when the air conditioner is turned off and 4.29% when turned on,compared with the initial results through the correction of the gear ratios.     

Effect of humidity and temperature on power electric field intensity

We measure power electric field intensity at a substation in southwestern P. R. China at various humidity levels and temperatures. Measurement data and a back propagation neural network are used to construct a model of electrical field intensity responses to fluctuations in humidity and ambient temperatures. The maximum error is 0.047 5. The results show that the power electric field intensity increases as humidity rises when the temperature is constant; when humidity is a constant, temperature changes do not affect the regularity of the electric field intensity in a consistent manner regularly.     

Study on constant current control of inductive power transfer with parameter identification

Aiminy at magnetic exciting current (resonant current) control, a constant current control method based on dynamic parameter identification is put forward. With energy conversion analysis, the energy storage, supply and dissipation functions of the system resonant network are constructed. The reflecting impedance identification functions are obtained by constructing the energy equilibrium relations in a period and among several periods. Furthermore, a constant current control strategy by regulating the system input voltage with Buck converter is presented. Combining the relations among system input voltage, the envelope of resonant current and the input of Buck converter, the constant current control law is proposed. The control law is verified with experiments. For the proposed method, in parameter identification, only the data of zero crossing point of resonant voltage and current are required, which reduces the complexity and costs of sampling system. Also, the constant current control law does not need complex computation and is easy to implement.     

Fast multi-pole preconditioned GMRES high order boundary element method for power frequency electric field of multi-medium

In order to improve the computational accuracy and cost for multi-medium power frequency electric field (PFEF) solved by low order boundary element method (BEM) and preconditioned generalized minimal residual (GMRES),a hybrid technique combining the high order BEM and fast multi-pole (FM) method has been introduced to low order BEM. The FM preconditioned GMRES high order BEM is proposed to solve three dimension electric field distribution. The high order BEM model for three dimension electric field distribution is built, and the basic principles and implementation steps of the FM preconditioned GMRES high order BEM are given. The higher accuracy has verified in two medium test models. Part key devices in 500 kV substation is carried out to demonstrate that FM preconditioned GMRES high order BEM is much faster and more efficient than the preconditioned GMRES BEM in the computational cost and the storage of computer. The simulation values of this method are compared with measured values in 500 kV substation. It is found that the max relative error is 8.65%, so this method is suggested for use in large-scale and multi-medium PFEF problems.     

Design of portable noninvasive detecting instrument for arteriosclerosis

The existing detecting instruments for arteriosclerosis are usually expensive and bulky. To overcome their disadvantages, a novel portable noninvasive detecting instrument for arteriosclerosis based on advanced RISC machines (ARM) and WinCE is developed and its clinical assessment experiment is carried out. Its hardware platform is an embedded system. The pulse wave signals of radial artery and brachial artery are acquired by signal measurement circuit and transmitted to ARM processor. On the basis of arterial Windkessel model and oscillometric theory, pulse wave signals analysis is performed by custom-designed software based on LabVIEW for WinCE platform, and 11 arterial stiffness assess factors are calculated. Subject’s degree of arteriosclerosis is evaluated automatically by this instrument according to these factors. The results of clinical experiment show that the instrument can accurately evaluate degree of arteriosclerosis and keep good stability and reliability. The maximum relative error of stability is 4.37%, and the correlation coefficient with the consulted instrument is higher than 0.85 (P<0.001).     

A method for calculating SOC of single Ni-MH battery used in hybrid electric vehicles

A performance test bench for power batteries in hybrid electric vehicles is built. According to vehicles’ real driving condition, the correlative charge and discharge experiments of power batteries are carried out in different environmental temperatures. A new algorithm about self-correction fuzzy neural network control is used to calculate the state of charge(SOC)of power batteries at 25 ℃, and the result is compared with that of Arbin test instrumentation. Theoretical analysis and experimental results suggest that the accuracy of SOC calculated by the algorithm of correction fuzzy neural network control under variable rate discharge for power batteries meets the requirements.     

Design and manufacturing integration support system for sheet metal processing shop of electrical equipment

Under the mode of customization-oriented multi-varieties and small-batch production, the requirement of design and manufacturing integration exists in sheet metal processing shops, which has the characteristics of great varieties of sheet metals, huge design data and heavy production tasks. To meet the requirement, an integrated operation mode for sheet metal processing shop of electrical equipment is presented. The mode realizes the information sharing and business collaboration from the sheet metal 3D CAD, 2D outspread, process design, optimal sheet metal layout, NC programming to NC machining. The integration framework based on service oriented architecture(SOA), function structure and operation process of the system is constructed. The system has been applied to an electrical equipment manufacturer in Chongqing, and good results are obtained.     

Parameter Design for the Power Train and Simulation of the Dynamic Performance of Elctrical Vehicle

The method and principle of the parameter design for the power train of EV is explored and discussed,then the parametersof EV. based on SC7101 are reasonably selected.The method of calculating the SOC of Lead_acid battery is provided and the relation among the electromotive force,the interior resistance, the polarized resistance and the SOC are analyzed. The capacity is compensated according to the relation between the capacity and the temperature, which is the basis on which the energy management system is designed and improved. The dynamic model which reflects the dynamic characteristics of the power train is established,then the dynamic performance of the EV based on SC7101 is simulated, and the factors that affect the continuous mileage of EV are analyzed,the measures to increase the continuous mileage are provided.The result shows that the analysis of the electric characteristics of battery and the dynamic model are correct,and the dynamic performance perfectly meets the need of the design target.     

New Design of Pre-amplification Circuit for EEG Signals

In the measurement of EEG signals ,the pre - amplification electrical signal of brain is the most importantant and key link. Whether the design is excellent or inferior is related to the electrical signal detection system of brain directly. The design of this circuit has been paid attention to by domestic and international expert all the time. On the basis of existing biological electricity amplifier which is studied, the authors consult the electric amplifier circuit of living beings designed , such as reference , improve and design a new-type and high performance electrical signal characteristic of brain in . The circuit has prevented the traditional design from enlarging the miscellaneous simulation of the circuit and straining the wave link, otherwise, this circuit is of simple structure , low cost, and convenient debugging. The paper has detailed theoritic analysis and experimental results to prove this circuit, which offered a new train of thought for reseach and development of brain electrical amplifier and other faint biological electricity amplifiers . This curcuit has be expected to win extensive application.     

Winter Air-conditioning I-d Pattern Design of Fan-coil Units

For the most common fresh air handling way supplying fresh air directly into the rooms after it has been handled in fan coil with outdoor air systems, the paper gives the design method of i d pattern in winter air conditioning operating mode, which determines the state of supply air of fan coil units and the final parameter of winter fresh air througn the ratio of fresh air. For selecting the final parameter of fresh air after it has been handled,the authors gives three conditions:Winter fresh air is handled to room enthalpy;Winter fresh air is handled between room enthalpy line and room temperature line; Winter fresh air is handled to room temperature or a little lower than room temperature. The comparing result show that the second method is desirable after comparison.     

励磁功率单元主回路快速故障诊断策略

分析总结了发电机组励磁系统功率单元的故障类型和常见故障,通过Matlab仿真功率单元主回路故障类型,重点研究基于故障频谱分析的定量故障特征提取和故障分类,提出了一种快速针对功率单元主回路的故障诊断真值表法,最后通过实验平台验证故障类别,结果表明：该方法能够正确有效地诊断出功率单元主回路具体的故障晶闸管,为励磁系统功率单元故障诊断提供依据。     

兵团农场农业资源管理服务信息系统的设计研究——以农八师149团为例

为了提高兵团农场农业资源管理水平,实现农业资源数据的有效共享,为从农人员提供所需的农业信息服务,笔者根据新疆生产建设兵团新型农场的经营与管理体制,结合计算机数据库技术和GIS技术,以149团为调研单位,设计了兵团农场农业资源管理服务信息系统,分析了系统建立的必要性,阐述了系统初步设计方案,包括数据类型分析、系统概念设计、系统结构设计等,展示了部分系统应用实例图,建立了一个集管理功能和服务功能于一体的一站式农业资源管理服务信息系统,使兵团农场已有的农业资源信息能够统一存储、高效管理和便捷共享,同时动态地存入现时资源数据,提高了团场农业资源管理水平。