A starter/generator system for an aircraft engine, the starter/generator system comprising: a three-phase squirrel cage induction machine; and a first three-phase inverter/converter/controller, ICC, unit (104, 900) operatively coupled to said three phase squirrel cage induction machine through a first electrical path, said ICC unit (104, 900) comprising: a three-phase inverter/converter electrically coupled to said three phase squirrel cage induction machine; a bidirectional DC-DC converter electrically coupled to said three phase inverter/converter; and a digital control board configured to sensorlessly determine a rotor angle from a plurality of phase currents to the induction machine during a start mode and to determine the rotor angle by integrating a summation of an estimated rotor speed and a slip speed during a generate mode; wherein during a start mode, logic in said digital control board configures said starter/generator system into a combination of induction motor using the induction machine, three phase DC-AC inverter using the inverter/converter, and DC-DC boost converter using the bidirectional DC-DC converter, and during a generate mode, the logic in said digital control board configures said starter/generator system into a combination of induction generator using the induction machines, three phase AC-DC converter using the inverter/converter, and DC-DC buck converter using the bidirectional DC-DC converter. a three-phase squirrel cage induction machine; and a first three-phase inverter/converter/controller, ICC, unit (104, 900) operatively coupled to said three phase squirrel cage induction machine through a first electrical path, said ICC unit (104, 900) comprising: a three-phase inverter/converter electrically coupled to said three phase squirrel cage induction machine; a bidirectional DC-DC converter electrically coupled to said three phase inverter/converter; and a digital control board configured to sensorlessly determine a rotor angle from a plurality of phase currents to the induction machine during a start mode and to determine the rotor angle by integrating a summation of an estimated rotor speed and a slip speed during a generate mode; a three-phase inverter/converter electrically coupled to said three phase squirrel cage induction machine; a bidirectional DC-DC converter electrically coupled to said three phase inverter/converter; and a digital control board configured to sensorlessly determine a rotor angle from a plurality of phase currents to the induction machine during a start mode and to determine the rotor angle by integrating a summation of an estimated rotor speed and a slip speed during a generate mode; wherein during a start mode, logic in said digital control board configures said starter/generator system into a combination of induction motor using the induction machine, three phase DC-AC inverter using the inverter/converter, and DC-DC boost converter using the bidirectional DC-DC converter, and during a generate mode, the logic in said digital control board configures said starter/generator system into a combination of induction generator using the induction machines, three phase AC-DC converter using the inverter/converter, and DC-DC buck converter using the bidirectional DC-DC converter.