Method and systems for an engine starter/generator

A method of controlling an engine starter/generator system for starting an engine and generating power using the engine, said method comprising:

• during a start mode:
• boosting an input voltage using a DC-DC converter;
• inverting the boosted DC voltage into a three phase AC output that drives an induction motor configured to rotate the engine;
• measuring two of the three phase currents, ia and ib;
• converting phase currents, ia and ib into id and iq, where id is the current aligning with the rotor flux linkage and iq is the current perpendicular to the rotor flux linkage;
• controlling a field of an induction machine of the starter/generator system using id;
• controlling a torque of an induction machine of the starter/generator system using iq;
• during a generate mode:
• applying a three phase output of the induction machine to the input of a the three phase converter to generate a three phase AC voltage;
• converting the three phase AC voltage into a DC voltage at a first voltage magnitude greater than a predetermined output voltage magnitude of the starter/generator system;
• bucking the DC voltage down to the predetermined output voltage magnitude of the starter/generator system using a cascaded DC-DC converter.