US 11,689,130 B2
Multi-stage serial turbo-generator system for supercritical CO2 power cycles
Chiranjeev Singh Kalra, Irvine, CA (US); and Matthew David Carlson, Littleton, CO (US)
Assigned to Heliogen Holdings, Inc., Pasadena, CA (US)
Filed by Heliogen Holdings, Inc., Pasadena, CA (US)
Filed on Sep. 2, 2021, as Appl. No. 17/446,816.
Claims priority of provisional application 63/074,766, filed on Sep. 4, 2020.
Prior Publication US 2022/0077798 A1, Mar. 10, 2022
Int. Cl. H02P 9/30 (2006.01); F01D 15/10 (2006.01); F02C 1/02 (2006.01)
CPC H02P 9/305 (2013.01) [F01D 15/10 (2013.01); F02C 1/02 (2013.01); F05D 2220/32 (2013.01); F05D 2220/76 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A supercritical CO2 system comprising:
a plurality of turbine generator units comprising a first turbine generator unit and one or more additional turbine generator units, each of the plurality of turbine generator units comprising:
a) a turbine with an input and an output;
b) a generator with a power output;
c) a shaft connecting the turbine and the generator;
d) a speed sensor for sensing a speed of the shaft;
wherein the input of the first turbine generator unit is configured to receive supercritical CO2 from a heat exchanger in communication with a heat source, and the input of each of the one or more additional turbine generator units is coupled to the output of the first turbine generator unit or one of the additional turbine generator units and configured to receive supercritical CO2 therefrom; wherein the plurality of turbine generator units form a series-connected cascade of turbine generators;
a direct current bus;
a plurality of active rectifiers, each active rectifier comprising a power input and power output; wherein the power input of each active rectifier is connected to the power output of the generator of one of the plurality of turbine generator units; and wherein the power output of each active rectifier is connected to a direct current bus configured to combine power from the plurality of active rectifiers;
a voltage controller configured to receive a speed from the speed sensor of each of the plurality of turbine generator units, and further configured output a control signal to the plurality of active rectifiers; wherein the voltage controller is configured to monitor the speed of each generator shaft and command each rectifier to vary a power electronic switching frequency to increase or decrease a load on each generator to control shaft speed; and
a compressor and a re-compressor each configured to receive a portion of the supercritical CO2 from the output of the turbine of a last of the plurality of turbine generator units, the compressor and re-compressor each configured to compress said portion of the supercritical CO2 that is recirculated to the heat exchanger.