Fourth-Order Buck-Boost Converters Exhibiting Minimum Phase by Reverse Inductor Coupling

Abstract

Three fourth-order buck-boost converters with improved dynamic response are proposed. The improved dynamic response is achieved starting from the uncoupled inductors topologies and performing reverse coupling. This leads to the shift of the right half plane (RHP) zeros to the left half plane (LHP). The state-space small signal model is developed and the control-to-output transfer functions are derived. A comparison is made to the uncoupled and direct coupled topologies revealing the RHP zeros elimination. The simulations confirm that also with reverse coupling the input and output currents still maintain their smooth nature.