Research On Rotor-Side Variable Frequency Drive And Its Control Strategy Of High Power Induction Motor

In this paper, a Rotor-Side Variable Frequency Drive is proposed, it can be used to regulate the rotating velocity of high power fan and pump. Simulations and experiments show that this method is featured by simple main circuit, reactor-less, high power factor, low harmonics, easy to start and by-pass operation. If it is applied to energy-saving, large benefits can be achieved.This paper includes:With studying all kinds of the cascade speed adjustment systems, we proposed a Rotor-Side Variable Frequency Drive with IGBT chopper and vector control IGBT voltage source inverter (VSI). Main circuit and operation theory is induced.We proposed a new peak current two-point control (NPCTC),which can solve effectively the problem of nonlinear stability in the conventional current two-point control. This method was applied to the both speed and current closed-loop control in rotor-side variable frequency drive.The power factor and harmonics in rotor-side variable frequency drive system is analyzed in details. The low harmonics is solved using active filter based on the instantaneous reactive power theory. The scheme was verified using extensive simulations. The results show the system performance is improved efficiently.Based on the detailed study of 3-phase power factor correction(PFC), a new 3-phase PFC topology with one-cycle control is introduced. The simulation results show that unity power factor can be realized. If applied to the rotor-side variable frequency drive system, the line-side low harmonics can be reduced and power factor can be increased.