Research on reducing EMI and output voltage ripple of buck converter based on a novel chaos control

Switching mode supplies usually emit electromagnetic interferences (EMI) at switching frequency and its harmonics. EMI can be reduced by making these systems worked on chaotic state, but this may induce higher output voltage ripple. Based on a new voltage feedback method, buck converter can display complex nonlinear behaviour. Compared with periodic state, power spectrum of inductance current is improved at chaotic state, the peak values at switching frequency and its harmonics are decreased; the output ripple voltage are also decreased. Pspice simulation results illustrated that this chaos control strategy not only improved the EMC of buck converters, but also reduced the output voltage ripple obviously. The decrease reason of output ripple voltage has been analyzed.