A speed monitor for establishing a lower threshold and an upper threshold for a speed of a rotor or shaft of a turbogenerator. A speed detector detects speed data or a speed signal for a rotor or shaft associated with a turbogenerator. A turbogenerator controller controls an output current of the turbogenerator based on the detected speed data or speed signal to control a rotational speed of the rotor or the shaft. A voltage monitor establishes a lower voltage limit and an upper voltage limit for a generator. A voltage detector detects an output voltage level associated with the generator. A motor/generator controller controls the output voltage level of the generator electrical output by invoking at least one of a motor mode and a generator mode based on the detected output voltage level to maintain a desired operational voltage range.