The large current generated by starting directly of super large capacity and high voltage induction motor would have a huge impact on the grid as well as the motor itself.The variation of the power factor and electrom...The large current generated by starting directly of super large capacity and high voltage induction motor would have a huge impact on the grid as well as the motor itself.The variation of the power factor and electromagnetic torque during direct start of motors with different capacity and voltage levels are obtained.Aiming at the problem that the secondary impact of auto-transformer starter is too large and the cost of magnetic control starter is too high,the auto-transformer and magnetic control soft start method of super large capacity and high voltage motor is proposed and the basic working principle is analyzed.The calculation formula of cost for magnetic control soft starter and auto-transformer and magnetic control soft starter is deduced,and specific examples are analyzed and compared.It is concluded that the choice of auto-transformer with appropriate tapping ratio can greatly reduce the cost of auto-transformer and magnetic control soft starter compared with the other one.Finally,the simulation and experiment results show that the start method can effectively avoid secondary current impact and constrain the motor starting current to less than 2.5 times the rated current.展开更多
同步电机软起动是由静止变频器(Static Frequency Converter,SFC)将同步电机从静止逐渐拖动至额定转速。但SFC短时和频繁起动会造成大量谐波,该谐波施加在同步电机电枢绕组对同步电机造成不可逆的危害。本文首先图解分析了同步电机软起...同步电机软起动是由静止变频器(Static Frequency Converter,SFC)将同步电机从静止逐渐拖动至额定转速。但SFC短时和频繁起动会造成大量谐波,该谐波施加在同步电机电枢绕组对同步电机造成不可逆的危害。本文首先图解分析了同步电机软起动低速和高速阶段的换相过程,由此推导出各阶段电枢电流模型,从而分析得出电枢电流谐波特性。最后,搭建出同步电机软起动的Matlab/Simulink模型,验证本文推导的准确性。展开更多
基金This work was supported in part by the National Key Research and Development Program of China under Grant 2017YFB0902904,in part by the Natural Science Foundation of Hubei Province under Grant 2016CFB448,and in part by the Shenzhen City Science and Technology Innovation Plan under Grant JCYJ20170306170937861,and in part by Wuhan City Science and Technology Program under Grant 2016070204020165.
文摘The large current generated by starting directly of super large capacity and high voltage induction motor would have a huge impact on the grid as well as the motor itself.The variation of the power factor and electromagnetic torque during direct start of motors with different capacity and voltage levels are obtained.Aiming at the problem that the secondary impact of auto-transformer starter is too large and the cost of magnetic control starter is too high,the auto-transformer and magnetic control soft start method of super large capacity and high voltage motor is proposed and the basic working principle is analyzed.The calculation formula of cost for magnetic control soft starter and auto-transformer and magnetic control soft starter is deduced,and specific examples are analyzed and compared.It is concluded that the choice of auto-transformer with appropriate tapping ratio can greatly reduce the cost of auto-transformer and magnetic control soft starter compared with the other one.Finally,the simulation and experiment results show that the start method can effectively avoid secondary current impact and constrain the motor starting current to less than 2.5 times the rated current.
文摘同步电机软起动是由静止变频器(Static Frequency Converter,SFC)将同步电机从静止逐渐拖动至额定转速。但SFC短时和频繁起动会造成大量谐波,该谐波施加在同步电机电枢绕组对同步电机造成不可逆的危害。本文首先图解分析了同步电机软起动低速和高速阶段的换相过程,由此推导出各阶段电枢电流模型,从而分析得出电枢电流谐波特性。最后,搭建出同步电机软起动的Matlab/Simulink模型,验证本文推导的准确性。
