Power receiving device and wireless power transmission system

A power receiving device comprising:

• a plurality of antennas;
• a plurality of rectifying sections each of which is provided to correspond to one of or a plurality of the antennas and converts electromagnetic waves received by the corresponding antenna into DC power and outputs the DC power;
• a connection switching section which is provided between the plurality of rectifying sections and a load and performs switching between serial/parallel connection states of the output side of the plurality of rectifying sections;
• a current measuring section which measures current flowing through the load;
• and
• a control section which, on the basis of measured current measured by the current measuring section, selects a serial/parallel connection state of the rectifying sections, the state enabling RF-DC conversion efficiency to be maximized, and controls the connection switching section so that the rectifying sections are connected in the selected serial/parallel connection state,
• wherein the control section includes
• first information in which input power of electromagnetic waves received by the plurality of antennas, load resistance, and the measured current are associated with each other, and
• second information in which the electromagnetic wave input power, the load resistance, and the RF-DC conversion efficiency are associated with each other,
• wherein, the control section acquires, from the first information, electromagnetic wave input power corresponding to present load resistance and to the measured current, and acquires, from the second information, load resistance at which a maximum RF-DC efficiency corresponding to the acquired electromagnetic wave input power is obtained, the control section switches the connection switching section so that the rectifying sections are in a serial/parallel connection state where load resistance closest to the obtained load resistance can be obtained.