DYNAMIC TUNING FOR WIRELESS CHARGING SYSTEM

摘要

A transmitter (110) includes an alternating current (AC) power source with tunable parameters. A tunable parameter may be capacitance, inductance, or frequency. A metric related to power transfer from the transmitter through a coil (130) is used to determine an amount to modify a parameter. One metric is equal to |Vs|-|Is|-cos(f), where |Vs| is magnitude of the power source voltage, |Is| is magnitude of the power source current, and f is phase difference between the power source voltage and power source current. Another metric is equal to |Vs|-|Is|-cos(f)- (Vcoil_ref/Vcoil), where Vcoil ref is a normalization value, and Vcoil is voltage across the coil (130). The transmitter may further include a phase tracking and adjustment loop, such as a phase-locked loop (PLL).