The present invention relates to a power transmission control device, a power transmitting device, a non-contact power transmission system, a secondary coil positioning method, and the like.
In recent years, non-contact power transmission (contactless power transmission) that utilizes electromagnetic induction to enable power transmission without metal-to-metal contact has attracted attention. As application examples of non-contact power transmission, charging a portable telephone, charging a household appliance (e.g., cordless telephone handset or watch), and the like have been proposed.
JP-A-2006-60909 discloses a non-contact power transmission device using a primary coil and a secondary coil, for example.
JP-A-2005-6460 discloses technology that detects misalignment of a primary coil and a secondary coil in a non-contact power transmission system. According to the technology disclosed in JP-A-2005-6460, whether or not the relative positional relationship between the primary coil and the secondary coil is correct is detected based on an output voltage of a rectifier circuit of a power receiving device. When the relative positional relationship between the primary coil and the secondary coil is correct, a light-emitting diode (LED) is turned ON to notify the user that the relative positional relationship between the primary coil and the secondary coil is correct.
According to the technology disclosed in JP-A-2005-6460, the user can be notified whether or not the primary coil and the secondary coil are accurately positioned. However, since occurrence of mispositioning is determined based on the output from the rectifier circuit of the power receiving device, power must be continuously transmitted from the power transmitting device to the power receiving device. Moreover, the power transmitting device cannot voluntarily acquire coil misalignment information.