Analysis And Control On The Low Frequency Oscillation Of The Induction Motor Drive System

For induction motor driven by voltage source SPWM inverter, the problem of low frequency sustained oscillation has often been observed in some state. It not only takes disadvantageous mechanism vibration, but causes undulation of the induction motor current and impairs the system of variable frequency speed regulation. The operation performance and reliability of the system are affected much more.A complete inverter-induction motor system simulation model, which takes induction motor's magnetic saturation and inverter's dead-time effect into accounts, is established based on MATLAB/SIMULINK in the paper. By dynamic simulating on low frequency operation of an induction motor, results verified the existence of the low frequency oscillation and the validity of the proposed model. From simulation results, the parameter effecting to the low frequency oscillation, of inverter-induction motor, is analyzed in details. The relation between dead time and low frequency oscillation is illustrated theoretically. By means of center manifold, we simplify the 5-dimension mathematical model of induction motor. In order to suppress the low frequency oscillation of system, on the one hand, we adopt based dead time compensation giving priority to soft achievement to suppress the oscillation. In addition, through adjusting parameter of the induction motor, we achieve the purpose to suppress the low frequency oscillation and improve the performance of system.