Design and passivity-based stability analysis of a PI current-mode controller for dc/dc boost converters

A nonlinear current-mode proportional-integral (PI) controller is proposed for the challenging problem of regulating the output voltage of a dc/dc boost power converter. For the analysis, the accurate average nonlinear model of the boost converter is used, while a new advanced passivity-based nonlinear stability analysis is applied. Particularly, it is firstly proven that the closed-loop system is passive and a unique equilibrium exists. A new sequential method is proposed for constructing a suitable Lyapunov storage function for the entire closed-loop system, which is capable to prove the input-to-state stability of the system. All these properties are eventually used to prove convergence to the desired equilibrium. Finally, the effectiveness of the proposed PI controller is evaluated through simulation and experimental results for cases where step changes on the voltage reference value occur.