Analysis of the Load Interactions in Constant-Current-Controlled Buck Converter

Abstract

The paper investigates the load interactions in constant-current-controlled buck converters. The nominal transfer functions and the load interaction formalism are derived from the voltage-output-converter model by applying duality. It is observed that the constant-current control makes the converter very sensitive to load interactions implying that a proper controller design is a necessity. The high crossover frequency in the nominal control-to-output transfer function may lead to performance degradation if the initial control design is done with resistive load, because the typical load for constant-current controlled converters is a low impedance storage-battery recovering the nominal feature. It is shown that electronic loads, typically used in prototype testing and verification, might have unexpected characteristics. This may lead to wrong deductions of the converter stability and performance