Second order sliding mode-based MPPT control for photovoltaic applications

- The MPPT technique is based on the second order sliding mode.
- With a sliding surface properly choosed, the proposed control law does not require reference voltage/current.
- A comparison between the first order and the second order sliding mode is made up to prove the effectiveness of the second order sliding mode.
- Simulation results are used to evaluate the robustness of the proposed system.

Taking into account the nonlinear feature of a PV array, a Maximum Power Point Tracking (MPPT) algorithm is required in a PV system leading the operation at the Maximum Power Point (MPP) and as a result maximizing the generated power. In this paper, a robust MPPT technique using second order sliding mode control strategy is presented. A super twisting algorithm is used to design second order sliding mode. This algorithm has been developed, in the case where the relative degree of system is equal to one, to eliminate chattering phenomenon. Second order sliding mode presents an adequate mean for control action of nonlinear systems since it overcomes chattering phenomenon of the classical first order sliding mode controller and ensures higher accuracy even with system imperfections. The stability analysis of the proposed controller is performed using a Lyapunov function. We compare second order sliding mode with classical first order sliding mode controller which are both designed for the same PV system. This comparison proves that the second order gives fast response and less chattering. The robustness and stability of the proposed controller are investigated against weather changes. Simulation results with real data, under MATLAB-SIMULINK, are given to demonstrate the effectiveness of the proposed approach.