Sepic PFC converter with notch filter based control

Sepic power factor correction converters are used now days to reduce the second stage in a two-stage PFC preregulator. Moreover the problem of inverted output voltage can also avoided. But the PFC converters, due to nonlinear effects will create line frequency instabilities and subharmonic oscillations in the line current. This can adversely affect the system and shorten its lifetime. So to avoid these problems a novel control technique has been proposed. A second order Notch filter can be incorporated into the outer voltage compensation loop. The suitable notch gain and quality factor helps to suppress the instabilities and THD in line current and thus enhance the stability of the system. The system has been designed in MATLAB/Simulink software and the performance of control scheme has been verified.