Impedance Matching for Inductive Power Transfer Systems

摘要

Methods and apparatuses for improved efficiency of power transfer across an inductive charging interface by adaptively changing the impedance of the receive coil in response to changes in load conditions during inductive power transfer are disclosed.

主权项

1. An electromagnetic induction power transfer apparatus comprising:
an inductive power transmitter, comprising:
a power supply with an active state and an inactive state, configured to switch between the active state and the inactive state at a selectable duty cycle; anda power-transmitting inductor coupled to the power supply; and an inductive power receiver, comprising:
a power-receiving inductor, positioned inductively proximate the power-transmitting inductor;a programmable load; andan impedance controller coupled to the power receiving inductor and configured to increase or decrease an electrical impedance of the inductive power receiver in response to a change in a power requirement of the programmable load.