Control of bifurcation in current-programmed dc/dc converters: An alternative viewpoint of ramp compensation

This paper reexamines the conventional current-mode control strategy as applied to dc/dc converters in the light of "avoiding bifurcation." This alternative viewpoint pen-nits convenient selection of parameter values to guarantee stable operation. The traditional slope compensation is viewed as a means to keep the system sufficiently remote from the first bifurcation point. It is shown that excessive bifurcation clearance is accompanied by undesirably slow dynamical response. A variable ramp compensation is proposed to dynamically adjust the slope magnitude so that the system is kept clear of bifurcation, yet responds sufficiently fast during transients. The results have been confirmed by experimental measurements.