LOAD RESISTANCE AND OUTPUT VOLTAGE ESTIMATION OF DC-DC BUCK CONVERTERS USING A CONSTANT GAIN OBSERVER

Abstract

This paper proposes an estimation method of the load resistance and output
voltage for DC-DC buck converters. The state-space model of the converter is
structured into the form of a locally uniformly observable system with the states
of the inductor current, output voltage, and load resistance. Additionally, by
using the Diode voltage of the converter as an input, a nonlinear observer is
formulated with a constant matrix gain to estimate the resistance and output
voltage. The observer is based on the output of the available inductor current,
which has been the feedback of the double-loop control system of the converter.
The observer is simple and robust with a single output and a constant gain.
Simulation results confirm the performance of the proposed observer that the
resistance and voltage can be sufficiently used for the feedback of voltage
regulator and power management system.