US 12,438,435 B2
Method for reduction of DC link busbar and capacitor current, by adjustment of a PWM carrier delay
Thomas Lundgren Andersen, Hinnerup (DK); and Morten Lindholm, Højbjerg (DK)
Assigned to VESTAS WIND SYSTEMS A/S, Aarhus N (DK)
Appl. No. 18/247,732
Filed by VESTAS WIND SYSTEMS A/S, Aarhus N (DK)
PCT Filed Sep. 30, 2021, PCT No. PCT/DK2021/050303
§ 371(c)(1), (2) Date Apr. 3, 2023,
PCT Pub. No. WO2022/069012, PCT Pub. Date Apr. 7, 2022.
Claims priority of application No. 2020 70667 (DK), filed on Oct. 1, 2020.
Prior Publication US 2023/0421041 A1, Dec. 28, 2023
Int. Cl. H02M 1/00 (2007.01); F03D 13/20 (2016.01); H02M 1/12 (2006.01); H02M 5/458 (2006.01)
CPC H02M 1/0048 (2021.05) [F03D 13/201 (2023.08); H02M 1/0009 (2021.05); H02M 1/0043 (2021.05); H02M 1/12 (2013.01); H02M 5/458 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for optimizing electrical current in a DC link busbar of a power converter system comprising:
a first inverter bridge, connected to the DC link busbar at a first end, the first inverter bridge having a first pulse width modulation signal, and
a second inverter bridge, connected to the DC link busbar at a second end, the second inverter bridge having a second pulse width modulation signal; and wherein the method comprises:
measuring a current flowing in the DC link busbar from the first end to the second end,
optimizing the current flowing in the DC link busbar by delaying the first pulse width modulation signal and the second pulse width modulation signal from each other with a carrier delay; wherein optimizing the current comprises:
minimizing power losses in the DC link busbar by deriving a model of a frequency dependent impedance of one or more conductors of the DC link busbar;
deriving at least one harmonic of the current flowing in the one or more conductors of the DC link busbar; and
calculating power losses in the DC link busbar based on the at least one harmonic and the model of the frequency dependent impedance of the one or more conductors of the DC link busbar.