Method of controlling impedance matching with respect to multiple targets in wireless power transmission system, and wireless power transmission system adopting the method

A method of operating a wireless power reception apparatus, the method comprising:

• transmitting information on a rectifier output voltage to a wireless power transmission apparatus;
• receiving a control command from the wireless power transmission apparatus;
• and
• controlling the rectifier output voltage based on the control command,
• wherein the control command is generated by the wireless power transmission apparatus based on comparing rectifier output voltages to one another, the rectifier output voltages comprising the rectifier output voltage in the information transmitted to the wireless power transmission apparatus,
• wherein whether the rectifier output voltages are within a predetermined operating range is determined by the wireless power transmission apparatus based on the rectifier output voltages, and
• wherein an impedance of the wireless power transmission apparatus is controlled by the wireless power transmission apparatus based on a result of the determining.

A wireless power transmission apparatus comprising:

• a communication unit configured to receive information on rectifier output voltages from at least one wireless power reception apparatus;
• a processor configured to:
• compare the rectifier output voltages to one another,
• control the communication unit to transmit, to the at least one wireless power reception apparatus, a control command to compensate for mismatching among the rectifier output voltages, and
• determine whether the rectifier output voltages are within a predetermined operating range;
• and
• an impedance matching control circuit configured to control an impedance of the wireless power transmission apparatus based on a result of the determining.