US 9,812,980 B2
Power conditioning units
Lesley Chisenga, Redwood Shores, CA (US); Gehan Anil Joseph Amaratunga, Cambridge (GB); and Cuauhtemoc Rodriguez, Cambridge (GB)
Assigned to SolarCity Corporation, San Mateo, CA (US)
Filed by SolarCity Corporation, San Mateo, CA (US)
Filed on Jan. 3, 2016, as Appl. No. 14/986,706.
Application 14/986,706 is a continuation of application No. 13/843,772, filed on Mar. 15, 2013, granted, now 9,270,191.
Application 13/843,772 is a continuation of application No. 12/789,154, filed on May 27, 2010, granted, now 8,405,367, issued on Mar. 26, 2013.
Application 12/789,154 is a continuation in part of application No. 12/160,743, granted, now 8,089,785, issued on Jan. 3, 2012, previously published as PCT/GB2007/050014, filed on Jan. 12, 2007.
Claims priority of application No. 0600658.9 (GB), filed on Jan. 13, 2006; and application No. 1004621.7 (GB), filed on Mar. 19, 2010.
Prior Publication US 2016/0226390 A1, Aug. 4, 2016
Int. Cl. H02M 5/458 (2006.01); H02J 3/38 (2006.01); H02M 7/48 (2007.01); H02M 5/45 (2006.01); H02M 1/08 (2006.01); H02M 1/00 (2006.01)
CPC H02M 5/458 (2013.01) [H02J 3/383 (2013.01); H02J 3/385 (2013.01); H02M 1/08 (2013.01); H02M 5/45 (2013.01); H02M 7/4807 (2013.01); H02M 2001/007 (2013.01); H02M 2001/0009 (2013.01); Y02E 10/563 (2013.01); Y02E 10/58 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of maximum power point tracking (MPPT) in a power conditioning unit for delivering power from a DC power source to an AC circuit output, the power conditioning unit including an energy storage capacitor for storing energy from the DC power source and a DC to AC converter delivering AC power to the AC circuit output, the method comprising:
tracking a maximum power point (MPP) of the DC power source by controlling the DC to AC converter to convert energy stored in the energy storage capacitor to AC power for the AC circuit output, wherein tracking an MPP comprises:
sensing, at a circuit node coupled to the energy storage capacitor, a signal responsive to a level of power drawn from the DC power source;
determining whether the level of power is increasing or decreasing relative to a previously sensed level of power; and
controlling a frequency of the DC to AC converter to maintain operation of the power conditioning unit at the MPP based at least in part on whether the level of power is increasing or decreasing.