Maximum power tracing method and system of photovoltaic system

The invention provides a maximum power tracing method and system of a photovoltaic system. A disturbance observer can be built according to various uncertainty factors such as non-linearity, parameteruncertainty and random shadow environment during working of a photovoltaic power generation system, a voltage disturbance estimation value and a current disturbance estimation value are obtained after a voltage observation value and a current observation value are input the disturbance observer, a sliding plane is calculated according to the voltage disturbance estimation value and the current disturbance estimation value, an actual control voltage and a control current are obtained by sliding-mode control on the two disturbance estimation value, and maximum power point tracing of photovoltaic power generation is finally achieved. Maximum power tracing of the photovoltaic system under a local shadow environment is achieved, and the maximum power point capturing capability of the photovoltaic system and the system