Design and evaluation of tri-state boost converter

A tri-state boost converter proposed earlier avoids the dynamic response problem of single-switch boost converter operating in continuous-conduction mode by providing an additional inductor-free-wheeling interval. The converter offers an additional degree of control-freedom. Two variations of a multi-variable dual-mode control (DMC) scheme that effectively exploit this control freedom and aim to attain a good compromise between the contradictory multiple-goals of achieving good dynamic performance and high efficiency have also been proposed earlier. The dynamic and steady-state performances of the converter under DMC are closely interrelated and in turn decide the size and rating of power components and also the design of feedback controllers. The aim of this paper is to investigate the trade-offs involved in the design of DMC based tri-state boost converter and to present a systematic design procedure for both variations of the DMC schemes. The relation between dynamic and steady-state performances is investigated and used appropriately in selecting the power and control components. An example design is presented and the design is validated through simulations and experiments.