Modelling of Passivity based Controller for Buck Boost Converter

DC-DC converters find applications in various control problems and the field of renewable energy, such as photo-voltaic (PV) generation. Affected due to partial shading, the input voltage profile of the converter can vary over a broad range. In this paper, a nonlinear control rule for buck-boost converters with broad variations in input supply voltage was developed utilising a passivity-based control method and a hamiltonian system perspective to obtain precise dynamic and steady-state characteristics. A converter state-space average model was used to gain the passivity-based controller (PBC). The PBC's stability and capacity to follow the fluctuating reference load voltage was tested and compared with the proportional-integral (PI) controller under variable input supply voltage and changing load voltage. The simulation findings reveal that, compared to the PI controller, the PBC has more resilience to disturbances in the input supply voltage and can react and monitor changing load voltage considerably faster. The PBC is straightforward to apply, and the converter will have improved steady and dynamic properties.