Maximum Power Point Tracking of a Photo-Voltaic system using Sliding Mode Control

Abstract

Enhancing the output power of the photo-voltaic (PV) systems requires necessity to track the maximum power point (MPP) robustly. The most techniques discussed in many researches have played a role in obtaining MPP at different conditions. Some of these techniques have some drawbacks, one of which is the oscillation around the operating point. This thesis suggests sliding mode control (SMC) technique to minimize and mend this problem. The strategy of SMC is to design a sliding surface which set the operating point. To reach this surface in finite time a control law must be applied to the DC-DC converter gate. The PV peak power can be obtained smoothly at different conditions by changing the duty cycle of the converter gate. The PV connected to the grid via seven level diode clamped multilevel inverter (7-level DCMLI). To prove the stability of the SMC, a comparison between perturb and observe (P&O) and SMC methods was done. Complete PV system was modeled and simulated using MATLAB/SIMULINK. Moreover, experimental prototype was implemented. The simulation and experimental results are compared for clarification and validation. These results agreed on that the SMC has low transient under sudden variation and reach the steady state point faster than P&O. Moreover, they confirmed the robustness, good performance of SMC strategy at different environmental conditions.