The Analysis of Nonlinear Dynamical Behaviours of Active Power Filter and its Capability of Suppressing EMI

In this paper, the nonlinear behaviors of active power filter (APF) are analyzed and the method to suppress the EMI is presented. The cause of nonlinear phenomenon mainly comes from the nonlinear specialty of the power switch in the converter. This article raises the nonlinear problem caused by the instability of the gate drive voltage of IGBT. The problem can be changed into the transmission process analysis of the instant pulse current produced from the process of IGBT on-off, the refrain of structural stability problem which caused by IGBT´ control voltage translated into interdiction of the spreading plus of the instant electric pulse or attenuation of spreading path, after the research of switching power supply in methods of simulation and test result. It is certain that flyback switching power supply can be used in the auxiliary switch power of APF and it will be useful for the APF to restrain the nonlinear problem