Secondly , combined with the comparatively ripe ac motor mathematic model , the energy characteristic model of motor among the drive - line of pev is built , then the changes of motor stator current and voltage under different working condition can be calculated 然后引用较成熟的三相异步交流电机的数学模型建立了纯电动汽车传动系中电机的能量特性模型。利用该模型可计算出动态条件下电机定子相电流、相电压的变化。
The ideal power system needs to be supplied with sine voltage whose frequency and amplitude are both stable . to three - phase ac power system , the currents and voltages must be equal of amplitude and the phase - shift between each other should be 120 of positive order 理想的电力系统要求以频率和幅值稳定的正弦电压进行供电；对于三相交流电力系统，各相电压和电流应处于幅值大小相等、相位互差120的正序对称状态。
Then one of the methods of rotor position detection - bemf zero crossing point detection is explained in detail . in succession , the chapter dissertates the method of measuring phase voltage and supply voltage , and analyses the error of rotor position using this method 对转子位置检测方法中的反电势过零点法作了比较详细的介绍，讨论了反电势法中相电压和端电压的检测方法，并分析了利用该方法时而产生的转子位置检测误差。
The generators are of three - phase four - wire type , making use of star connection with neutral point . the rated line voltage is 400v . phase voltage 230v . frequency 50hz , power factor 0 . 8 ( lag ) . it can provide 60hz and the other voltage ' s generator according to necessary 本发电机为三相四线制，采用带有中性点的星接法，额定电压为400伏，相电压为230伏，频率50赫，功率因素0 . 8 （滞后）根据用户需要，也可提供60赫及其它电压值的发电机。
And it analyses the power factor in different conditions via the fourier anlysis of the stator current and voltage . then , it sets up the simulating model for maximum torque / current ratio . the torque can be controlled by controlling the angle of stator current vector 在矢量控制实现的基础上,采用傅立叶分解分析电机的相电流和相电压,得到矢量控制系统中电压和电流的基波分量和相位角,进而判断电机的功率因数,分析在不同控制情况下电机的功率因数状况。
Switching losses analysis indicates that the switching losses can be extremely reduced with different load qualities by choosing proper phase - voltage modulation method . the method of minimum switching losses svm is investigated . the modulation functions of a quasi - optimum method and a two - phase modulation method are given 本文深入研究了一种基于电压空间矢量的最小开关损耗pwm技术，给出了准优化方法和二相优化方法的相电压调制函数，并在理论分析的基础上，通过仿真实验，对两种减少开关损耗的方法和调制与过调制进行了分析。
Specific issues examined are : compensation for the variation of the stator resistance , the offset error of the dc bus voltage , the voltage error generated by the forward voltage drop the dead time of the switches , improvement of the steady state performance , and the speed sensorless control for the pmsm dtc drive system are of major concern in this thesis 定子电阻变化，直流母线电压漂移，开关器件反向相电压降、逆变器死区时间引起的电压误差的补偿，提高系统稳态运行性能以及永磁同步电机直接转矩控制的无速度传感器运行方案等问题都是本文研究的重点。转矩的快速响应是直接转矩控制算法的一个卓越的性能。
Intelligent electricity quantity concentration display instrument is a kind of intelligent instrument used to measure combined parameter of ac electricity quantity , which can simultaneously measure each phase electricity parameter in the tri - phase ac loop such as voltage , current , active power , reactive power , apparent power , power factor , frequency , active kilowatt hour , reactive kilovolt ampere - hour and so on 智能电量集中显示仪是一种用于交流电量综合参数测量的智能仪表,它可以同时测量三相交流回路的每一相电压电流有功功率无功功率视在功率功率因数频率有功电度无功电度等参数。
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。
Because central potentials of four y windings in 12 - phase generator are not equal each other and there is no common reference inside the generator , it is difficult to identify the on / off of rectifying elements . in this paper , by using a mathematical model with line voltage substitute for phase voltage , the problem that there is no common reference in the 12 - phase generator with rectifier is solved . based on results of the studies on small prototype , 920kw charging generator applied in a submarine is improved in design , and therefore power oscillation with high magnitude when two generators are operating in parallel 由于十二相发电机中四个y绕组的中点电位不等，电机内部没有公共参考点，从而在判断整流元件导通时，不能象三相同步发电机整流系统那样认为阳极电位最高或阴极电位最低的整流元件导通，本文采用了以线电压代替相电压建立十二相整流发电机的数学模型，从而解决了十二相发电机无公共参考点的问题。
