Performance Analysis of Tri-state Boost and Buck-Boost Converters for Impedance Matching Circuits

Tri-state boost and buck-boost converters are proposed as unique topologies to address the right-half-plane (RHP) zero issue present in conventional boost and buck-boost converters, which adversely affects system dynamics and overall stability. This is achieved by introducing an additional operating mode, known as the inductor freewheeling mode, in the Continuous Conduction Mode (CCM) of these converters. This added mode creates an opportunity to use these converters in impedancematching circuits by treating the main and freewheeling duty cycles as two degrees of freedom for control. Therefore, this paper presents the analysis and performance of tri-state boost and buck-boost converters operating in CCM, with a focus on their use of two degrees of freedom for impedance-matching applications. The equivalent input and output resistances of these converters are analytically derived with respect to both the main and freewheeling duty cycles to evaluate the extended control range provided by the additional freewheeling duty and its potential application in impedance-matching circuits. The results are validated using PSIM simulations. Finally, a comprehensive comparison with conventional converters is conducted to enable a more thorough performance assessment.