An Adaptive Estimator-Based Sliding Mode Control Scheme for Uncertain POESLL Converter

The positive output elementary super lift Luo (POESLL) converter is a dc-dc converter with a simple structure, which can increase input voltage with low ripples and high voltage gain. This study proposes an adaptive estimator-based sliding mode control scheme for the POSELL converter considering a reduced-order model of the converter with an unknown load and unknown input voltage. The proposed controller is composed of two parts: 1) an adaptive estimator, and 2) the sliding mode controller. At first, it is assumed that the state variables of the converter are available and adaptive estimator is proposed to facilitate the design of adaptive laws for estimating unknown parameters. Then, the sliding mode control input is designed based on the estimation of unknown parameters. Stability analysis of the proposed scheme is provided and σ-modification type robust adaptive laws for estimating the uncertain parameters are derived based on the Lyapunov direct method. Furthermore, one modification term is proposed to satisfy the sliding condition. Finally, the proposed scheme is experimentally implemented in real time using STM32F407VG discrete signal processor board interfaced with MATLAB. In addition, in order to compare and highlight the effective performance of the proposed scheme, the proportional-integral (PI) controller is designed and implemented. Experimental results are presented for both of the proposed approach and the PI one. The results verify the ability of the proposed scheme for voltage regulation as well as its robustness against parameter uncertainties. Additionally, comparison results demonstrate that the proposed controller has superior performance than the PI controller.