US 12,267,012 B2
Voltage balance systems and methods for multilevel converters
Zheyu Zhang, Clifton Park, NY (US); Tomas Sadilek, Durham, NC (US); Ramanujam Ramabhadran, Niskayuna, NY (US); and Hao Tu, Raleigh, NC (US)
Assigned to GE GRID SOLUTIONS LLC, Atlanta, GA (US)
Appl. No. 17/619,397
Filed by General Electric Company, Schenectady, NY (US)
PCT Filed Jun. 17, 2019, PCT No. PCT/US2019/037508
§ 371(c)(1), (2) Date Dec. 15, 2021,
PCT Pub. No. WO2020/256690, PCT Pub. Date Dec. 24, 2020.
Prior Publication US 2022/0311337 A1, Sep. 29, 2022
Int. Cl. H02J 7/00 (2006.01); H02J 7/14 (2006.01); H02M 1/00 (2006.01); H02M 3/158 (2006.01)
CPC H02M 3/158 (2013.01) [H02J 7/0014 (2013.01); H02M 1/0025 (2021.05); H02J 2207/20 (2020.01)] 20 Claims
OG exemplary drawing
 
1. A multilevel converter system comprising:
a converter comprising a first segment and a second segment electrically connected to said first segment, wherein said first and second segments are each configured to convert a first current to a second current, wherein said first segment comprises a plurality of first switches, and wherein said second segment comprises a plurality of second switches;
a balancing reference current generator configured to generate a balancing reference current; and
a converter controller interfaced with said converter, said converter controller comprising:
a voltage loop configured to receive a first voltage from said first segment, a second voltage from said second segment, and a reference voltage, wherein said voltage loop is further configured to generate a reference current;
a current loop configured to:
receive a current output of said converter, the reference current generated by said voltage loop, and the balancing reference current generated by said balancing reference current generator; and
generate output signals based on the current output of said converter, the reference current, and the balancing reference current; and
a voltage compensation loop configured to:
receive the first voltage from said first segment, the second voltage from said second segment, and a sign signal indicating a polarity of the current output of said converter; and
generate output compensation signals based on the first voltage, the second voltage, and the sign signal,
wherein said converter controller is configured to generate first pulse-width modulation (PWM) signals and second PWM signals using the output signals from said current loop and the output compensation signals from said voltage compensation loop, wherein the first PWM signals are configured to control said plurality of first switches, wherein the second PWM signals are configured to control said plurality of second switches, and wherein the first and second PWM signals are configured to balance the first voltage with the second voltage.