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。
Considering the above control strategies which make the controller can not be real - time processing because its workload has increased , control circuits of the main switches based on eprom are designed , which can implement control scheme of firing angles and phase voltage . furthermore , it avoids power converter saturation in the process of commutation 上述控制策略的引入造成控制器运算量增大、难以在线实时控制,又设计了基于eprom的主开关器件通断控制电路,实现了开关磁阻电动机开通关断角控制及对施加于相绕组上电压的优化控制,同时避免了换相时可能引起的功率变换器饱和现象。
Impedance - matching balanced traction transformers ( balanced transformers in this paper for short ) are step - down transformers , they transfer symmetrical three phase voltage in primary side to perpendicular two phase voltage in secondary side . they are different from any other transformers , so their short - circuit current analysis and short - circuit test method must be taken into special account 阻抗匹配平衡牵引变压器(本文中简称平衡变压器)是一种将一次侧三相对称电压变换为二次侧二相垂直电压的降压变压器,它不同于已有的任何一种变压器,短路电流的分析计算和短路试验必须予以重新研究。
When single - phase ground fault occurs in this system , the fault current is much low and the phase - phase voltage is still symmetrical . so the system still can supply power to load . although many researchers have done much concerning on fault location for years , the key problem remain unsolved because of the undistinguished fault feature 多年以来,许多科研人员在小电流接地系统单相接地故障定位方面作了大量工作,但由于该系统单相接地故障特征不明显,虽然取得一定的进展,但尚未取得实质性的突破,在实际中也无较好应用。