Mitigating Chattering Phenomenon for Photovoltaic System Using Sliding Mode Control Under Rapid Irradiation Level Variation

Maximum power point tracking (MPPT) presents an important method for ensuring the optimal operation of photovoltaic systems (PVS). In this paper, we present an MPPT method based on combining the MPPT method: Perturb and Observe (P&O) with the sliding mode controller which is an external voltage controller. To achieve high-performance control, particularly in terms of accuracy and repid response, we propose the integration of derivative and integral terms into the sliding surface. In general, the Sliding Mode Control (SMC) consists of two parts: the equivalent and discontinuous control laws. However, the discontinuity related to the discontinuous control law often leads to a chattering phenomenon. To solve this problem, we replace the sign function in the conventional SMC method with its sigmoidal approximation. The proposed MPPT method is evaluated under conditions of rapid irradiation changes using the MATLAB/Simulink environment. Furthermore, the proposed method is compared to the P&O MPPT algorithm with a proportional-integral (PI) controller and to the P&O MPPT algorithm with conventional SMC. The simulation results of the suggested MPPT approach demonstrate high dynamic performance, particularly in the case of fast variations in irradiance.