Magnetic coupling device and wireless power transmission system using the same

A wireless power transmission system comprising:

• a magnetic coupling device includes:
• a power transmitting coil and a power receiving coil magnetically coupled to each other;
• a signal transmitting coil and a signal receiving coil magnetically coupled to each other;
• a first magnetic body constituting a magnetic path of a first magnetic flux interlinking the power transmitting coil and the power receiving coil;
• and
• a second magnetic body constituting a magnetic path of a second magnetic flux interlinking the signal transmitting coil and the signal receiving coil;
• a power transmitting circuit that converts an input DC voltage into an AC voltage and outputs the AC voltage to the power transmitting coil;
• a control circuit that controls the AC voltage output from the power transmitting circuit based on the AC signal received by the signal receiving coil;
• a power receiving circuit that converts the AC voltage generated in the power receiving coil into a DC voltage;
• and
• a signal generating circuit that generates an AC signal indicating the magnitude of the output voltage or output current from the power receiving circuit,
• wherein a permeability of the first magnetic body is larger than a permeability of the second magnetic body at a driving frequency of the power transmitting coil and smaller than a permeability of the second magnetic body at a driving frequency of the signal transmitting coil higher than the driving frequency of the power transmitting coil.