Modelling and implementation of fixed switching frequency sliding mode controller for negative output elementary super lift Luo-converter

This study presents a reduced-order state-space average model and a fixed switching frequency (FSF) sliding mode controller (SMC) for the negative output elementary super lift Luo-converter (NOESLLC) operated in continuous conduction mode for application fields requiring the constant power source such as medical, telecommunication, industrial, military etc. The NOESLLC is an attractive dc-dc converter that can provide high-voltage transfer gain. Owing to the time-varying switched mode operation, the dynamic performance of the NOESLLC becomes highly non-linear. In order to enhance the dynamics performance and output voltage regulation of the NOESLLC, the FSFSMC is developed. The proposed FSFSMC is more appropriate to the inherently variable-structured NOESLLC when represented in the reduced-order state-space average-based mathematical model. The three conditions of FSMSMC applicable to the NOESLLC, namely, existence, reaching and stability conditions are analysed. The performance of the developed controller is validated for its robustness to perform over a wide range of working conditions through both in MATLAB/Simulink models and as well as in the laboratory prototype with the comparative study of a typical proportional-integral-controller. Theoretical analysis, simulation and experimental results are presented to demonstrate the feasibility of the designed FSFSMC along with the complete systematic design procedure.