Research on MPPT Algorithm Based on Variable Step Conductance Increment Method and Sliding Mode Control

The traditional incremental conductance (INC) method is used to achieve the maximum power point tracking (MPPT) of photovoltaic (PV) array, but the algorithm suffers from some drawbacks of limited tracking speed, steady state oscillations and inaccurate tracking in case of rapid environment change. To solve these problems, this paper proposes a MPPT method for a stand-alone photovoltaic power generation system using a variable step incremental conductance method and sliding mode control (SMC). The variable step divides different voltage intervals and designs different voltage step size calculation methods. Compared with the traditional INC algorithm, the speed of MPPT and steady-state accuracy are improved. Besides, the voltage controller based on sliding mode control is designed to guarantee the stability, fastness and accuracy of the MPPT under parameter perturbations. The actual output voltage of PV array and the MPP voltage determined by the variable step INC method error can converge to zero, thus the MPPT is achieved. Finally, the effectiveness and feasibility of the proposed method is verified through simulation studies.