Research on the passivity-based control strategy of Buck-Boost converters with a wide input power supply range

Abstract

DC-to-DC converters are widely applied at the field of renewable energy such as photovoltaic(PV) generation and wind energy generation. Affected by the speed of wind, the front end power supply of a converter often changes over a wide range. DC-to-DC converters are typical nonlinear dynamical systems. To gain fine dynamic state and steady state characteristics, in this paper, a nonlinear control law, a passivity-based control scheme, for a Buck-Boost converter with a wide range of input power supply was developed. The stability of the system was studied and a passivity-based controller (PBC) was gained on the basis of a converter state-space average model. The converters only by using a passivity-based controller have week robustness against the input power supply disturbance. A PBC scheme with a proportional integral (PI) controller was presented. The simulation results show that the PBC with PI controller is with strong robustness against disturbance caused by the front end power supply. The PBC combined with PI control strategy is simple and easy to implement, and the system has better dynamic state and steady state characteristics.