The main function of MPPT controller is to detect the DC voltage and output current of the main circuit, calculate the output power of the solar array, and track the maximum power point. The disturbance resistor R is connected in series with the MOSFET. Under the condition that the output voltage is basically stable, the average current through the resistor is changed by changing the duty ratio of the MOSFET, thus causing current disturbance. At the same time, the output current and voltage of the photovoltaic cell will also change accordingly. The change of the output power and voltage of the photovoltaic cell before and after the disturbance is measured to determine the disturbance direction of the next cycle. When the disturbance direction is correct, the output power of the solar photovoltaic panel will increase, and the next cycle will continue to disturb in the same direction. Otherwise, it will disturb in the opposite direction. In this way, the disturbance and observation will be repeated to make the solar photovoltaic panel output reach the maximum power point.
