Sweep frequency mode for multiple magnetic resonant power transmission

摘要

A power transmission pad is configured to provide wireless power transmission to multiple portable electronic devices where each device is orientation-free relative to the pad. The power transmission pad is also configured to be power adaptive by changing the power transmission level depending on the number of devices being concurrently charged. Each device, is placed within the magnetic field for the purpose of charging the device battery. The power transmission pad includes a sweep frequency generator for generating power transmissions across a frequency spectrum. The number of devices to be charged is determined as well as an optimal frequency for maximum energy transfer to each device. A single combined optimal frequency is determined using the optimal frequencies determined for each individual device. The sweep frequency generator is locked to the single combined optimal frequency and a power transmission level is set according to the number of devices.

主权项

1. A power transmission pad for wireless power transmission comprising:
a. a coil; b. a power transmitter having a sweep frequency generator coupled to the coil to provide a frequency varying signal through the coil, thereby generating a variable magnetic field; and c. a controller coupled to the coil and to the sweep frequency generator, wherein when a plurality of portable electronic devices to be charged are positioned within the variable magnetic field a handshake protocol is performed between each of the portable electronic devices and the power transmission pad, wherein the power transmission pad is configured to determine the number of portable electronic devices positioned within the variable magnetic field by counting a number of handshake protocols and to adjust a power transmission level of a power transmission signal according to the determined number, wherein the power transmission pad is further configured to determine an optimal device frequency from the frequency varying signal for each portable electronic device where the optimal device frequency corresponds to a frequency where a maximum energy transfer occurs from the power transmission pad to the portable electronic device, and to determine an optimal system frequency of the power transmission signal using the determined optimal device frequency of each portable electronic device, wherein the optimal system frequency is an average of the determined optimal device frequency for each portable electronic device.