摘要
为了提高异步电机的起动性能,解决电机起动时出现较大尖峰电流、转矩响应较慢等问题,分析了上述问题出现的主要原因,进而提出一种基于空间矢量及定子电阻压降补偿的异步电机交流预励磁起动方法。该方法的本质是对磁链的控制,在空间矢量理论的基础上,对电机的动态方程进行深刻分析,揭示了起动电流过大的主要原因是由于磁链的不稳定,进而采用交流预励磁方法分别对励磁和转矩控制,使电机内部磁场在电机起动前平稳建立,而后控制电机的起动,并在整个动态过程中利用定子电阻压降补偿来抑制低频时磁链的波动。仿真结果表明,本方法能够使圆形旋转磁链逐步稳定的建立,实现了控制系统的良好解耦效果,能有效地减小起动尖峰电流,并且维持磁链幅值的稳定,更有利于电机的平稳起动。
In order to improve the asynchronous motor start performance,solve the problems including the large peak current and the slow output torque response,analyze the main reasons for the large start current,a scheme on asynchronous motor AC pre-excitation start based on space vector and stator voltage drop compensation was proposed. The essence of the method is to control the flux,on the basis of space vector theory,deeply analysis the dynamic equation of the motor,revealing that the main reason for the excessive start current is due to the instability of the flux,then use AC pre-excitation method to respectively control the excitation and the torque,the internal magnetic field was set up smoothly before the motor start,and in the whole dynamic process use the stator voltage drop compensation to restrain the fluctuation of the flux in the low frequency. The simulation results show that this scheme can make the circular rotating flux smoothly set,which achieve the good decoupling effect of the control system,can effectively reduce the start peak current,maintain the flux amplitude stability,and more conducive to the motor smooth start.
引文
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