Model-Based Design and Sliding Mode Control Approach for Two-Stage Water Pumping System With Reduced Sensors

This article proposes an efficient control scheme for a two-stage water pumping system. The proposed method has three primary objectives. The first objective is to attain the maximum power point (MPP), which realizes using an improved MPP tracking algorithm. The second objective is to regulate the dc-link voltage, which is usually obtained by a PI controller. The PI controller is sensitive to parameter variation making the system unstable during dynamic conditions. Therefore, this article proposes a sliding mode controller (SMC) for dc-link voltage regulation. The proposed SMC also employs a continuous switching function to reduce the chattering issue. The last objective is to estimate the dc-link voltage. It is achieved using a mathematical model-based design approach considering the dynamics of the dc-dc converter. MATLAB Simulink and experimental analysis are used to validate the overall system performance. The proposed method accurately estimates and regulates the dc-link voltage with reduced oscillations under various dynamic conditions. The merit of the proposed system is to eliminate the need for a dc-link voltage sensor and speed encoder. Therefore, the proposed method is economical and efficient for water pumping applications.