Apparatus, systems and methods for scalable 3D wireless charging utilizing multiple coils
A wireless power transfer (WPT) system is provided to drive multiple resonator coils utilizing one power amplifier. The WPT system may include a power amplifier, a differential 1:N power divider, impedance inversion circuits and multiple resonator coils. The WPT system may further include auto-tuning circuits with sensors that facilitate the efficient driving of the multiple resonator coils. As well, there is provided various 3D shaped coil topologies that are comprised of two or more separate coils. The 3D coil topology designs each provide a particular 3D magnetic field for wireless charging.
1 . A resonant wireless power transfer (WPT) transmitter device for 3D wireless charging, the device comprising:
a power amplifier;
two or more coils;
a power divider for dividing a power output of the power amplifier to each of the two or more coils, wherein the power amplifier drives the two or more coils to generate a 3D magnetic field for wirelessly charging mobile devices;
a matching circuit for converting the power output from the power amplifier into a constant voltage source
an impedance inversion circuit for each of the two or more coils for converting the constant voltage source into a constant current; and
an auto-tuning circuit with sensors for reactance shift detection, wherein the auto-tuning circuit is connected between the matching circuit and the power divider.
2 . The resonant WPT transmitter device of claim 1 , wherein the power divider is a 1:N differential power divider, wherein N is an integer ≥2.
3 . The resonant WPT transmitter device of claim 2 , wherein the differential power divider is one of: a differential coupler power divider; a differential Wilkinson power divider; a differential modified Wilkinson power divider; a differential ferrite core transformer power divider.
4 . The resonant WPT transmitter device of claim 1 , wherein input feed positions of the two or more coils are proximate to each other.
5 . The resonant WPT transmitter device of claim 4 , wherein proximity of the input feed positions of the two or more coils increases an efficiency of the WPT transmitter device.
6 . The resonant WPT transmitter device of claim 1 , wherein the auto-tuning circuit comprises a circuit for each coil of the two or more coils for tuning the respective coil to resonant at the same frequency as a receiving coil.
7 . The resonant WPT transmitter device of claim 1 , comprising:
a matching network comprising the matching circuit and impedance inversion circuits for each of the two or more coils,
the matching circuit being connected between an output of the power amplifier and an input of the power divider,
outputs of the differential power divider being connected to the two or more coils through respective impedance inversion circuits for converting the constant voltage into a constant current.
8 . The resonant WPT transmitter device of claim 7 , comprising for each coil, an auto-tuning circuit with sensors for reactance shift detection, wherein for each coil, the auto-tuning circuit is connected between the impedance inversion circuit and the coil.
9 . A resonant wireless power transfer (WPT) system, the WPT system comprising:
a 3D coil topology comprising two or more coils for generating a 3D magnetic field over a charging area;
a power amplifier; and
a differential power divider for dividing power from the power amplifier to each of the two or more coils;
a matching circuit for converting the power output from the power amplifier into a constant voltage source
an impedance inversion circuit for each of the two or more coils for converting the constant voltage source into a constant current; and
an auto-tuning circuit with sensors for reactance shift detection, wherein the auto-tuning circuit is connected between the matching circuit and the power divider,
wherein each of the two or more coils have a feed point, and the feed points of the two or more coils are positioned so that a current feed to each coil is in-phase or near in-phase, to improve efficiency.