Maximum power point tracking method of photovoltaic power generation system

The invention discloses a maximum power point tracking method for a photovoltaic power generation system, which comprises a starting stage and an operation stage, in the starting stage, the position near the maximum power point is quickly reached by a fixed current method, then the reference voltage at the maximum power point in the current environment is locked by a variable step size perturbation and observation method, and then the operation stage is entered; in the operation stage, the P-U curve is partitioned by about 12% of a reference voltage point, and it is guaranteed that the voltage working point is always located in the region of about 12% of the reference voltage point; and meanwhile, judging whether the environment is greatly changed or not, and if the environment is greatly changed, correcting the dP so as to adjust the step length. According to the invention, the self-adaptive step length tracking method is realized. According to the method, energy loss can be reduced to the greatest extent, m