By establishing the discrete iterative mapping model of a current mode controlled buck-boost converter,this paper studies the mechanism of mode shift and stability control of the buck-boost converter operating in discontinuous conduction mode with a ramp compensation current.With the bifurcation diagram,Lyapunov exponent spectrum,timedomain waveform and parameter space map,the performance of the buck-boost converter circuit utilizing a compensating ramp current has been analysed.The obtained results indicate that the system trajectory is weakly chaotic and strongly intermittent under discontinuous conduction mode.By using ramp compensation,the buck-boost converter can shift from discontinuous conduction mode to continuous conduction mode,and effectively operates in the stable period-one region.
