US 11,909,246 B2
Method and system for an AC battery
Martin Fornage, Petaluma, CA (US); and Mauricio Cespedes Moya, San Francisco, CA (US)
Assigned to Enphase Energy, Inc., Petaluma, CA (US)
Filed by Enphase Energy, Inc., Petaluma, CA (US)
Filed on Dec. 1, 2021, as Appl. No. 17/539,681.
Application 17/539,681 is a continuation of application No. 15/952,735, filed on Apr. 13, 2018, granted, now 11,218,006.
Claims priority of provisional application 62/485,219, filed on Apr. 13, 2017.
Prior Publication US 2022/0140622 A1, May 5, 2022
Int. Cl. H02J 7/00 (2006.01); G01R 31/3842 (2019.01); H02J 7/02 (2016.01); H02M 7/66 (2006.01); G01R 31/392 (2019.01)
CPC H02J 7/007184 (2020.01) [G01R 31/3842 (2019.01); H02J 7/0014 (2013.01); H02J 7/0029 (2013.01); H02J 7/00032 (2020.01); H02J 7/0048 (2020.01); H02J 7/00712 (2020.01); H02J 7/02 (2013.01); G01R 31/392 (2019.01); H02J 7/00304 (2020.01); H02J 7/00309 (2020.01); H02J 2207/20 (2020.01); H02M 7/66 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for AC battery operation, comprising:
determining, at a battery management unit (BMU) coupled to an AC battery system comprising a power converter and a battery that is rechargeable, an equivalent series resistance estimation by correlating a ripple voltage and a ripple current, which exists on a DC battery during power conversion, at twice a line frequency, the equivalent series resistance estimation indicates a state of a charge (SOC) process of the AC battery system;
coupling, by a bias control module of the BMU, the equivalent series resistance estimation to the power converter for communicating, without a control area network, at least one of a state of health (SoH) of the battery or a degradation of the battery to and from the BMU and the power converter;
when one of a battery voltage reaches a high or low end of battery operation or a high or low end of estimated state of charge (SOC) of the battery, reducing a current when an estimated ESR increases;
determining, at each of the BMU and the power converter, a bias control voltage and SOC values; and
periodically synchronizing estimated SOC values with one another.