This method uses wavelet transform to pick up the transient fault information because of its multi - resolution characteristics and time - frequency localization nature . fault line is detected based on the modulus maxima or energy comparison under some scale of wavelet transform of phase currents or component current . this method is applicable for such power system as only furnished with ct on two phases , so the shortcoming of other methods presented in recent years is overcome 即利用相应出线相电流或分量的暂态信息突变量在小波变换某一尺度下模极大值或能量比较来确定故障线路,该方法同样适用于只装设两相ct的小电流接地系统,从而克服了迄今为止提出的一些选线方法在系统只装设两相ct时失效的问题。
In sensored case , the theory of hall signal checking ahd how to change phase are discussed . in sensorless design , using a single line resistance measure phase current and estimating rotor position are brought forward by analyse associate codes . at the same time , problems and solution which meet in task are mentioned in report 在有位置传感器方案设计过程中,详细讨论了霍尔位置信号检测原理和换相控制原理以及实现过程;在无位置传感器方案设计中,提出了单电阻电流检测原理和位置估算的算法,并且对相关的软件代码进行了分析。
Wp - le series intelligent power instrument input and measurement parameter scope include : dc voltage , dc current , ac single phase voltage , single phase current , tri - phase voltage , tri - phase current , single phase active power , single phase reactive power , tri - phase active power , tri - phase reactive power , single phase active electric energy , single phase reactive electric energy , tri - phase reactive electric energy , power factor power frequency and so on Wp le系列智能电力仪表输入及测量电参数范围包括:直流电压直流电流交流单相电压单相电流三相电压三相电流单相有功功率单相无功功率三相有功功率三相无功功率单相有功电能单相无功电能三相有功电能三相无功电能功率因数cos工频频率等。
Through research on principle and approach , this paper puts forward three new methods in power cable fault location . the first method is based on wavelet reconstruction , and the measured signal which is the difference between the faulty and sound phase current under the high voltage pulse excitation , is transformed using wavelet , and the high frequency component is reconstructed at single scale 基于小波重构的电缆故障测距方法采用脉冲电源作用下故障相与健全相的电流差作为测量信号,利用小波变换对其作多尺度分解,然后对信号在高频下进行单支重构。
Firstly , the experimental phase current and input power data obtained from load test are employed to estimate the parameters in ii rated condition . then , the phase current and input power data in locked rotor condition are used to track the variation of the parameters of the secondary coil with slip frequency . the classical method and the direct modification method are also used to estimate the parameters of the induction machine in comparison with this technique 首先利用了负载试验的定子电流和输入功率数据来识别额定工况下的电机参数,然后又使用了堵转时的定子电流、输入功率数据来识别电机二次绕组参数随转差频率的变化,并与传统参数测试方法和直接修正参数法进行了比较。
Secondly , in order to make the motor commutate exactly , a fuzzy neural network is used - to estimate the rotor position . based on the relationship of voltage , current , flux linkage and corresponding position ( ) , a fnn is proposed whose structure and parameters are trained based on improved genetic algorithm . through measurement of the phase voltages and phase currents , the flux linkage can be figure out 根据无刷直流电机中的电压、电流、磁通和转角之间的相互关系,构造一个基于遗传算法训练网络结构和参数的模糊神经网络,通过检测电机的相电压和电流计算出相磁通,然后利用计算出的相磁通和电流作为网络的输入,经网络运算后,得出电机转子的转角。
Computation method based on fast fourier transformation ( fft ) is studied deeply , whose measurement accuracy is 0 . 2s . the computing indexes involve voltage , current , power , frequency , phase , electric power , the harmonic ratio and the total harmonic distortion ( thd ) of phase voltage and phase current 深入研究了测量精度为0 . 2s级的基于快速傅立叶变换( fft )的电压、电流、功率、频率、相位、电能等电力参数和各相电压电流各次谐波含量、谐波含有率、谐波总畸变率的计算方法。
In order to consider the different heating of positive - sequence current and negative - sequence current of the motor stator generally , the equivalent current is adopted instead of the traditional phase current . the way how to gather positive - sequence current and negative - sequence current is brought forward , and the recurrence fourier - algorithm is adopted to calculate the effective value of current and voltage , the effective value of positive - sequence current and negative - sequence current 为了全面考虑感应电动机定子正序电流和负序电流的不同发热效应,提出了正序电流和负序电流获取的方法,并采用递推傅氏算法来实现电流、电压及电流正序和负序分量的有效值的计算。
This paper puts emphasis on dynamic simulation based on switched reluctance drivers ' s ( srd ' s ) nonlinear model , and study of fuzzy control for srd . based on switched reluctance motor ' s linear , nonlinear model , the dynamic simulation model of srd ' s is built respectively . the phase current , phase torque , total torque and speed of srm in current chopping control ( ccc ) and angular position control ( apc ) are calculated respectively with this simulation 本文在分析sr电机线性、准线性、非线性模型的基础上建立了四相( 8 / 6极) sr电机调速系统( srd )动态线性、非线性仿真模型,分别对电流斩波控制方式( ccc )与角度位置控制方式( apc )下sr电机相电流、一相转矩、合成转矩及角速度进行了仿真。
This software has realized functions of the sampling of stator phase current , calculating of the phase voltage , the observing of stator flux and the output of switching signal etc . according to the analysis of the theory of dtc scheme and the design of the control software , the author of this paper has done the primary experiments of the open - loop hexagon flux control system using the dsp test - bed for experimentation and development of motor control F240内部的外设模块为电机控制提供的硬件功能,使软件编程的工作得到大大的简化,它的实时运算能力大大提高了电机的控制性能和可靠性。在本文中采用dsp汇编语言完成了有速度传感器的直接转矩控制系统的软件编写,实现了定子相电流采样、相电压的计算、定子磁链的观测、开关信号输出等功能。