Optimization of MPPT in Both Steady and Transient States Through Variable Parameters

In photovoltaic (PV) systems, maximum power point tracking (MPPT) techniques are used in order to extract the maximum power from PV panels. So far, different MPPT methods have been presented. In all of these methods, two MPPT parameters, perturbation amplitude (D) and perturbation period (T₏), have a great effect on the MPPT efficiency. In this paper, first, the dynamic behavior of PV systems are assessed in both steady and transient states with the use of the small signal model and the simulation. The PV operating point has different behavior in the steady and transient states; therefore, in the proposed method, first, a state of the system is identified. Afterwards based on characteristics of each state which are assessed in the dynamic behavior of the PV system, the MPPT parameters are optimized. D is variable and based on the slope of the P-V curve with two different scaling factors; furthermore, the linear and exponential functions are used to determine the variable T₏ based on an operating state. In order to prove the superiority of the proposed method over the existing methods, the simulations are done in MATLAB/Simulink and PSIM software, and also comparison is conducted between the proposed method and the previous works.