Multi-stage serial turbo-generator system for supercritical CO2 power cycles

A supercritical CO2 system coupled to a heat source, the supercritical CO2 system comprising:

• a plurality of turbine generator units comprising a first turbine generator unit, a second turbine generator unit, and a third turbine generator unit, each of the plurality of turbine generator units comprising:
• a) a turbine with an input and an output;
• b) a generator;
• and
• c) a shaft connecting the turbine and generator;
• wherein the input of the first turbine generator unit is configured to receive supercritical CO2 from a heat exchanger in communication with the heat source;
• wherein the input of the second turbine generator unit is coupled to the output of the first turbine generator unit and configured to receive supercritical CO2 therefrom;
• wherein the input of the third turbine generator unit is coupled to the output of the second turbine generator unit and configured to receive supercritical CO2 therefrom;
• a plurality of active rectifiers, each active rectifier connected to one generator of one of the plurality of turbine generator units;
• and wherein the plurality of active rectifiers are configured to convert alternating current from the plurality of generators to direct current;
• a voltage controller configured to output a control signal to the plurality of active rectifiers to vary a load on each generator to control a rotational speed of each generator;
• and
• a compressor and a re-compressor each configured to receive a portion of the supercritical CO2 from the output of the turbine of the third turbine generator unit, the compressor and re-compressor each configured to compress said portion of the supercritical CO2 that is recirculated to the heat exchanger.

A supercritical CO2 system coupled to a heat source, the supercritical CO2 system comprising:

• a plurality of turbine generator units comprising a first turbine generator unit and a second turbine generator unit, each of the plurality of turbine generator units comprising:
• a) a turbine with an input and an output;
• b) a generator;
• and
• c) a shaft connecting the turbine and generator;
• wherein the input of the first turbine generator unit is configured to receive supercritical CO2 from a heat exchanger in communication with the heat source;
• and
• wherein the input of the second turbine generator unit is coupled to the output of the first turbine generator unit and configured to receive supercritical CO2 therefrom;
• a plurality of active rectifiers, each active rectifier connected to one generator of one of the plurality of turbine generator units;
• and wherein the plurality of active rectifiers are configured to convert alternating current from the plurality of generators to direct current;
• a voltage controller configured to output a control signal to the plurality of active rectifiers to vary a load on each generator to control a rotational speed of each generator;
• and
• a compressor and a re-compressor each configured to receive a portion of the supercritical CO2 from the output of the turbine of the second turbine generator unit, the compressor and re-compressor each configured to compress said portion of the supercritical CO2 that is recirculated to the heat exchanger.