The Dynamic Sliding Mode Controller with Observer of Coincident Perturbations and States for Buck Converter of Fuel Cell Source

Abstract

Buck converter has been widely used in the DC renewable energy system application. The Fuel Cell (FC) based DC renewable energy is offered as a high-performance and low-emission power supply, which replaces conventional DC sources. Its relevant control system has regulated the output voltage under input voltage and load resistance variations to track the desired reference signal. To control the current sensorless-based buck converter with matched and mismatched uncertainties, the system must be modeled in such a way that by measuring the output voltage, both the inductor current and system perturbations can be estimated. The purpose of the work is suggestion of a novel dynamic sliding mode controller (DSMC) based on observer of coincident perturbations and states (CSPO) to enhance its controllability and tracking performance. The significance of the work lies in low cost and reduced losses due to the inductor current measurement. Lacking an exact value for inductor current, it is not possible to estimate and compensate the perturbations caused by parametric uncertainties in the buck converter. These objectives were achieved by modeling in the canonical form. The canonical model somehow converts both the matched and mismatched perturbations into the matched perturbation, in which the system states and perturbations can be merely estimated using only an output voltage value and a CSPO. The most important results are the fastness and robustness of the DSMC to control the buck converter and compensate the effect of mismatched uncertainties and nonlinear disturbances and chattering phenomenon.