Voltage Stabilization of dc/dc Converter-driven Constant Power Loads via Feeding-back the Output Measured Current

Abstract

A new approach and a novel solution to the voltage control problem of a dc/dc boost converter feeding an arbitrary constant power load (CPL) is developed. Particularly, as CPLs exhibit negative incremental resistance, a fact that in combination with the nonlinear nature of a converter/CPL system creates ad hoc stability problems, a nonlinear control design is proposed with main purposes: i) to be effective on regulating the output voltage regardless of the power absorbed, ii) to be easily implemented as a feedback loop from measurable states and outputs. In the feedback loop the measurable current at the power load side is fed back diminishing the need to apply any adaptation or other complicated mechanism for estimating the power absorbed by the CPL. Hence, the proposed controller analysis is based on the complete closed-loop nonlinear model instead of using standard linearized techniques and asymptotic stability is proven by applying suitable Lyapunov methods. This design approach extends the controller validity in a wide range while in practice it can be easily realized. The stable and good performance of the controller is finally evaluated by simulations taken with various CPL levels.