The step-power method study for the maximum power tracking of single-stage photovoltaic grid-connected inverter

Based on the characteristics of PV array model, static and dynamic mathematical models of the single-stage PV power grid-connected generation system under the condition of power control are established in this paper. The voltage trajectory of PV array is studied by means of phase diagram analysis, which provides the basis for designing the maximum power point tracking algorithm. A step-power tracking algorithm is proposed according to the trajectory analysis of PV array voltage. Without the DC side current sensor, the algorithm overcomes the shortcomings such as the collapse of the bus voltage caused by traditional perturbation and observation method, the incorrect tracking of maximum power point in the weak light case. The validity and correctness of this method is verified by simulations and experiments.