Patent ID: 7310245
Filing Date: 2007-12-18
Classification: H02M,Y02B

Abstract:
1. An electric power transmission device for magnetically coupling a primary side power transmission coil to a secondary side power receiving coil and for transmitting electric power from said primary side power transmission coil to said secondary side power receiving coil via a non-contact and out of touch, said electric power transmission device comprising: at least one capacitor connected in series to said primary side power transmission coil, for converting a voltage which is to be supplied to said primary side power transmission coil into an AC voltage and being stepped up, and for configuring a series resonance circuit which includes a mutual inductance by said secondary side power receiving coil, phase detection means for detecting a phase of a voltage of said primary side power transmission coil; and control means for outputting a control signal to control the amount of electric power that is supplied to said primary side power transmission coil based on an output of said phase detection means, wherein a resonance point of said series resonance circuit which includes said mutual inductance by said secondary side power receiving coil is set to a frequency higher than a resonance point of a primary side series resonance circuit which is composed of said primary side power transmission coil and said capacitor, and said control means determines as no load when delaying in phase of a voltage of said primary side power transmission coil compared to a voltage to be supplied to said primary side power transmission coil, and determines as a foreign material load when advancing, at this time a first control signal for intermittently supplying electric power to said primary side power transmission coil at predetermined intervals during predetermined time only is outputted; and determines as a normal load when being in the same phase, and a second control signal for continuously supplying electric power to said primary side power transmission coil is outputted.