Tri-state boost converter with no right half plane zero

Abstract

A challenging problem in the design of boost converters operating in continuous conduction mode is posed by the dynamically shifting Right Half Plane (RHP) zero in the converter's small signal control-to-output transfer function. The paper proposes a novel tri-state boost converter without such a zero in the transfer function. The additional degree of freedom introduced in the converter in the form of a freewheeling interval has been exploited through an easy control technique to achieve this. The absence of the RHP zero allows the control scheme to achieve larger bandwidth under closed loop conditions, resulting in fast response. Analytical, simulation and experimental results of the tri-state boost converter have been presented and compared with the classical boost converter both under open loop and under closed loop operating conditions. The results clearly demonstrate the superior dynamic performance of the proposed converter. The proposed converter can be used in applications where fast response boost action is needed such as for single-phase power factor correction.