A compressor surge control system (210; 310; 410) comprising: a rotor system (202; 402A, 402B) comprising at least one compressor section (204; 204A, 204B) and at least one turbine section (208; 208A, 208B) operably coupled to a shaft (206; 206A, 206B); one or more rotor system sensors (218; 218A, 218B) configured to collect a plurality of sensor data from the rotor system; an electric motor-generator (212; 212A, 212B) coupled to the shaft (206; 206A, 206B) directly or through a geared interface, the electric motor-generator configured to increase a load on the rotor system when operating in a generator mode and to decrease the load of the rotor system when operating in a motoring mode; drive electronics (214; 214A, 214B) configured to control current to the electric motor-generator to adjust speed and/or torque of the electric motor-generator when operating in the motoring mode and to regulate electric power produced by the electric motor-generator when operating in the generator mode, wherein the drive electronics comprise power regulating circuitry and/or power converters to regulate electric power produced by the electric motor-generator in the generator mode; and a controller configured to monitor the one or more rotor system sensors while the rotor system is rotating, characterized in that the controller is further configured to: determine whether the plurality of sensor data from the one or more rotor system sensors is indicative of an early-stage compressor surge oscillation; determine a surge control torque to diminish the early-stage compressor surge oscillation; and command the electric motor-generator in the motoring mode, in which a supplemental motive force is supplied to the shaft, to apply the surge control torque to the rotor system, wherein the controller is configured to drive the electric motor-generator to apply the surge control torque by applying one or more torque perturbations to a steady state load of the rotor system (202; 402A, 402B) to modify the early-stage compressor surge oscillation of the rotor system. a rotor system (202; 402A, 402B) comprising at least one compressor section (204; 204A, 204B) and at least one turbine section (208; 208A, 208B) operably coupled to a shaft (206; 206A, 206B); one or more rotor system sensors (218; 218A, 218B) configured to collect a plurality of sensor data from the rotor system; an electric motor-generator (212; 212A, 212B) coupled to the shaft (206; 206A, 206B) directly or through a geared interface, the electric motor-generator configured to increase a load on the rotor system when operating in a generator mode and to decrease the load of the rotor system when operating in a motoring mode; drive electronics (214; 214A, 214B) configured to control current to the electric motor-generator to adjust speed and/or torque of the electric motor-generator when operating in the motoring mode and to regulate electric power produced by the electric motor-generator when operating in the generator mode, wherein the drive electronics comprise power regulating circuitry and/or power converters to regulate electric power produced by the electric motor-generator in the generator mode; and a controller configured to monitor the one or more rotor system sensors while the rotor system is rotating, determine whether the plurality of sensor data from the one or more rotor system sensors is indicative of an early-stage compressor surge oscillation; determine a surge control torque to diminish the early-stage compressor surge oscillation; and command the electric motor-generator in the motoring mode, in which a supplemental motive force is supplied to the shaft, to apply the surge control torque to the rotor system, wherein the controller is configured to drive the electric motor-generator to apply the surge control torque by applying one or more torque perturbations to a steady state load of the rotor system (202; 402A, 402B) to modify the early-stage compressor surge oscillation of the rotor system.