MPPT for Photovoltaic System using non-linear Hybrid Robust Integral Backstepping Controller

The PV (Photovoltaic) cells have a non-linear current-voltage (I-V) and power-voltage (P-V) characteristics with a unique maximum power point (MPP), which entirely depends on the environmental conditions. So, to continuously extract maximum power from a PV system under varying environmental conditions, the maximum power point tracking (MPPT) control approach is needed to operate the PV system at MPP. Therefore, in this article, a non-linear hybrid robust integral backstepping MPPT control approach is proposed for stand-alone PV system. The system consists of PV array, noninverted DC-DC buck-boost converter and a resistive load. The resistive load is interfaced to PV array through the buck-boost converter. The designed MPPT control approach continuously adjust the duty cycle of the converter, in such a way that the PV array output voltage tracks the reference voltage, thus ensuring the maximum power extraction. The performance of the designed MPPT approach is tested and validated in MATLAB/Simulink under fast varying environmental conditions, varying load, faults and parametric uncertainties occurs in the PV system. The proposed control approach presents a zero overshoot, fast convergence, good transient response, less rising time, a minimum tracking error and a very fast reaction against environmental conditions. To show the superiority and robustness of the proposed MPPT control approach a comparative analysis is presented with the backstepping and PID control approaches.