US 11,750,030 B2
Coil driving in wireless charging system
William Paul Abajian, Napa, CA (US); Jules Marie Xavier Laffitte, San Mateo, CA (US); John MacDonald, San Francisco, CA (US); Viswajit Natarajan, San Jose, CA (US); Christopher William Sarli, San Francisco, CA (US); Lixin Shi, Redwood City, CA (US); Jake Lee Vander Ploeg, San Francisco, CA (US); Xiaoping Zhu, Moraga, CA (US); and Mark Huan Mekkittikul, Hollister, CA (US)
Assigned to AIRA, INC., Phoenix, AZ (US)
Filed by AIRA, INC., Chandler, AZ (US)
Filed on Jan. 30, 2020, as Appl. No. 16/777,763.
Claims priority of provisional application 62/834,919, filed on Apr. 16, 2019.
Prior Publication US 2020/0336008 A1, Oct. 22, 2020
Int. Cl. H02J 7/00 (2006.01); H02J 50/10 (2016.01); H02J 50/40 (2016.01); H02J 7/02 (2016.01); H02J 50/80 (2016.01); G01R 23/16 (2006.01); H02J 50/90 (2016.01); H02J 50/12 (2016.01); H01F 38/14 (2006.01); H04B 5/00 (2006.01)
CPC H02J 50/10 (2016.02) [G01R 23/16 (2013.01); H01F 38/14 (2013.01); H02J 7/02 (2013.01); H02J 50/12 (2016.02); H02J 50/40 (2016.02); H02J 50/402 (2020.01); H02J 50/80 (2016.02); H02J 50/90 (2016.02); H04B 5/0037 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A non-transitory computer readable storage medium comprising stored instructions to drive a coil of a charging system, the instructions when executed causing a microcontroller to:
configure a sampling frequency for an analog-to-digital converter based on an operating frequency of the coil, wherein the operating frequency of the coil is greater than the sampling frequency configured for the analog-to-digital converter;
use the analog-to-digital converter to obtain measurements of voltage and current in the coil;
configure a discrete Fourier transform size to be used by the microcontroller based on the operating frequency of the coil;
detect presence of one or more objects based on a change in the measurements of voltage and current in the coil;
use a feedback control system to determine target characteristics of a coil driving signal when the one or more objects are present, the feedback control system comprising a coil driving circuit and the microcontroller when configured with the discrete Fourier transform size;
select a frequency and a duty cycle associated with a pulse width modulation (PWM) signal based on the target characteristics; and
generate the PWM signal based on the selected frequency and duty cycle to provide the generated PWM signal as an input to a half-bridge inverter in the coil driving circuit,
wherein the half-bridge inverter is configured to generate the coil driving signal and to provide the generated coil driving signal to the coil, and
wherein the sampling frequency and digital Fourier transform size are selected to avoid collisions of harmonic signals.