Tri-State Coupled Inductor Based High Step-Up Gain Converter Without Right Hand Plane Zero

Abstract

This brief proposes a novel tri-state Coupled Inductor (CI) based high step-up gain converter without Right Half Plane (RHP) zero. The basic Coupled Inductor based Boost Converter (CIBC) can achieve high step-up gain by changing the turn ratio of CI and duty cycle. However, the control to output voltage transfer function of basic CIBC converter in CCM has RHP zero hence non-minimum phase behavior with limited bandwidth and unstable operation of the converter when step changes in duty cycle. RHP zero can be eliminated from the basic CIBC by providing freewheeling period in converter operation hence additional degree of freedom to control energy transfer to output capacitor. Thus, the converter achieves stable operation and improves the bandwidth. The small-signal model of the proposed converter is derived to verify the claim. All theoretical findings are verified by experimental results. Experimental results are provided from implemented laboratory prototype of input voltage of 24 V to output voltage of 100 V and 200 W power.