Dynamical mechanism of ramp compensation for switching converter

Abstract

By introducing ramp compensation current into the feedback control circuit of current controlled switching DC-DC converter it can not only effectively extend the stable operation range of the switching DC-DC converter to realize chaotic stability control, but also shift its operation mode from discontinuous conduction mode to continuous conduction mode to realize operation mode shift. Taking current-controlled buck-boost converter as example by establishing the two-dimensional discrete-time model and the corresponding Jacobian matrix of current-controlled buck-boost converter with ramp compensation and two inductor current borders, the dynamical mechanism of ramp compensation for switching DC-DC converter is investigated. By analyzing the conditions of the instability and border collision bifurcation, the effects of the ramp compensation on the stable period oscillation and operation mode shift of switching DC-DC converter are discussed, and the corresponding stability boundary and mode shift boundary are obtained. Finally, an experimental circuit is built and the results are observed, from which the physical significance of the ramp compensation for chaotic stability control and operation mode shift of switching DC-DC converter is illustrated and the correctness of theoretical analysis is verified.