A closed-loop I/f vector control for permanent magnet synchronous motor

For the disadvantages of the open-loop I/f control used in permanent magnet synchronous motor, such as the velocity fluctuation and prone to loss synchronism, a closed-loop I/f vector control method based on power droop characteristic was proposed in this paper. This method is according to the positive correlation between the reference frequency variation and the power variation, which is derived by the estimated power through the high pass filter. Then the closed loop control system of reference frequency was obtained by using P adjuster in order to solve the problems of the velocity fluctuation and loss synchronism. The proposed control method was verified by simulation and test results.