A modified current sensorless approach for maximum power point tracking of partially shaded photovoltaic systems

The present paper proposes a modified current sensorless approach to reduce the implementation cost of maximum power point tracking (MPPT) controller for photovoltaic (PV) systems under partial shading conditions (PSCs). The proposed scheme relies only on the input voltage signal without the need for a current sensor to track the global maximum power point (GMPP). This is performed using a predefined objective function derived from the mathematical model of the buck-boost converter with an adaptive step-size mechanism for quick convergence. In addition, a formula of lower and upper limit duty cycle values for every local peak is incorporated for fast detection of local power peaks. An extensive experimental study, using a hardware prototype composed of a buck-boost converter driven by a dSPACE DS1104, is carried out to validate the proposed control scheme. Experimental results show that the proposed controller is able to accurately track the GMPP with high speed under various PSCs scenarios. Additionally, the proposed scheme reduces the implementation cost by 27.95% compared to conventional MPPT techniques.