US 11,990,842 B2
Method and system for balancing multi-phase LLC power converter with switch-controlled capacitors
Bo Sheng, Kingston (CA); Xiang Zhou, Kingston (CA); Wenbo Liu, Kingston (CA); Yang Chen, Kingston (CA); Yan-Fei Liu, Kingston (CA); Andrew Yurek, Kingston (CA); Lakshmi Varaha Iyer, Troy, MI (US); Gerd Schlager, Kefermarkt (AT); Michael Neudorfhofer, Sankt Valentin (AT); and Wolfgang Baeck, Sankt Valentin (AT)
Assigned to MAGNA POWERTRAIN GMBH & CO KG, Lannach (AT)
Appl. No. 17/425,621
Filed by MAGNA INTERNATIONAL INC., Aurora (CA)
PCT Filed Jan. 24, 2020, PCT No. PCT/US2020/014937
§ 371(c)(1), (2) Date Jul. 23, 2021,
PCT Pub. No. WO2020/154588, PCT Pub. Date Jul. 30, 2020.
Claims priority of provisional application 62/796,555, filed on Jan. 24, 2019.
Claims priority of provisional application 62/796,547, filed on Jan. 24, 2019.
Prior Publication US 2022/0103081 A1, Mar. 31, 2022
Int. Cl. H02M 3/335 (2006.01); B60L 53/20 (2019.01); H02M 1/00 (2006.01)
CPC H02M 3/33576 (2013.01) [B60L 53/20 (2019.02); H02M 1/0058 (2021.05); B60L 2210/10 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A method of operating a multi-phase LLC power converter comprising:
switching an input power at a switching frequency by a switching stage of each of a plurality of LLC phases to apply a switched power to a resonant tank having a resonant inductor, a resonant capacitor, and a parallel inductance, the switched power approximating an alternating current (AC) waveform having a switching frequency;
varying the switching frequency to control an output voltage of the multi-phase LLC power converter;
calculating a switch-controlled capacitor (SCC) conduction phase angle for each of the LLC phases to cause each of the LLC phases to have equal resonant frequencies; [and] adjusting a capacitance of the resonant capacitor of at least one of the plurality of LLC phases by operating an SCC switch in accordance with an associated one of the SCC conduction phase angles;
measuring a primary-side current in the resonant tank of each of the LLC phases; and
adjusting the SCC conduction phase angle for one of the LLC phases having a primary-side current that is different from a primary-side current of another one of the LLC phases, wherein adjusting the SCC conduction phase angle for the one of the LLC phases having the primary-side current that is different from the primary-side current of a different one of the LLC phases further comprises at least one of:
adjusting the SCC conduction phase angle for the one of the LLC phases in response to the primary-side current of the one of the LLC phases being different from the primary-side current of another one of the LLC phases for a time exceeding a first timing threshold; or
adjusting the one of the one of the LLC phases in a first direction and adjusting the other one of the LLC phases in a second direction opposite of the first direction in response to the primary-side current of the one of the LLC phases being different from the primary-side current of the different one of the LLC phases for a time exceeding a second timing threshold.