US Patent 9991715 Maximum power point tracking method and apparatus

A maximum power point tracking method is provided. The method includes the following steps. Perform a power conversion operation by a converter according to a duty cycle signal so as to convert an input power supplied by an energy harvester into an output power, wherein the converter includes an inductor, and a current flowing through the inductor increases in an energy-storing duration and decreases in an energy-releasing duration. Obtain a length of the energy-releasing duration. Adjust the duty cycle signal according to the length of the energy-releasing duration so as to track a maximum power point of the input power or the output power.