Abstract: A method and apparatuses are implemented for electric power systems. An apparatus for power conversion according to one embodiment comprises: a multiple function power converter (77), the multiple function power converter (77) being capable of performing functions of a static inverter, and being capable of at least one of performing functions of a motor controller, and performing functions of a start converter to use a generator as a starter. An architecture system for aircraft according to another embodiment comprises: one or more rectifiers (408), wherein the one or more rectifiers (408) receive at least one high frequency AC power input; and a plurality of power conversion devices (78) optionally connectable to drive at least one high frequency generator (105) as a starter and at least one load, the input of each power conversion device (78) being connected to at least one rectifier (408).

Abstract: A starter-generator system is configured to supply power to an aircraft electrical bus having a rated AC voltage magnitude, or receive power from a start converter, and includes a rotor and a stator. The stator is disposed at least partially around at least a portion of the rotor and has at least one multi-phase stator winding set wound thereon that has an increased number of turns per phase that is greater than a least number of turns per phase needed to supply power to an aircraft electrical bus at the rated AC voltage magnitude. The increased number of stator turns results in reduced current drawn by the starter-generator during the motor mode, which improves the efficiency and introduces other benefits to the overall starting system.

Abstract: A method and apparatuses are implemented for electric power systems. An apparatus for power conversion according to one embodiment comprises: a multiple function power converter (77), the multiple function power converter (77) being capable of performing functions of a static inverter, and being capable of at least one of performing functions of a motor controller, and performing functions of a start converter to use a generator as a starter. An architecture system for aircraft according to another embodiment comprises: one or more rectifiers (408), wherein the one or more rectifiers (408) receive at least one high frequency AC power input; and a plurality of power conversion devices (78) optionally connectable to drive at least one high frequency generator (105) as a starter and at least one load, the input of each power conversion device (78) being connected to at least one rectifier (408).

Abstract: A starter-generator system is configured to supply power to an aircraft electrical bus having a rated AC voltage magnitude, or receive power from a start converter, and includes a rotor and a stator. The stator is disposed at least partially around at least a portion of the rotor and has at least one multi-phase stator winding set wound thereon that has an increased number of turns per phase that is greater than a least number of turns per phase needed to supply power to an aircraft electrical bus at the rated AC voltage magnitude. The increased number of stator turns results in reduced current drawn by the starter-generator during the motor mode, which improves the efficiency and introduces other benefits to the overall starting system.

Abstract: A method and apparatus for executing a no-break power transfer between an electrical power generator powered by an auxiliary power unit (APU) and an electrical power generator powered by an aircraft main engine. The method comprises sending a power transfer command, a load/unload amplitude signal, and a target frequency signal from a bus power control unit to an APU electronic control unit; deriving a calculated load range for the APU at a new load and frequency operating point; and determining if the new load and frequency operating point falls within the calculated APU load range. If within range, a no-break power transfer is initiated; if not within range, a power transfer with momentary interruption is initiated.

Abstract: An apparatus (80) controls a synchronous machine (20) used to start an engine (300) during an engine start operation. The apparatus comprises: an exciter current control unit (84) for controlling exciter current output to the synchronous machine (20) during the engine start operation; and a main current control unit (82) for controlling main current output to the synchronous machine (20) during the engine start operation as a function of machine speed. In one implementation, the main current control unit (82) controls main current output to the synchronous machine (20) so that the synchronous machine (20) exhibits a reduced output torque during an initial torque application stage. The reduced viscous drag effects and reduced impact torque are beneficial to the engine system (100).

Abstract: Two spool gas turbine engines are often used to drive variable speed loads, such as an electric generator, or the fan/propeller of aircraft engines. The gas turbine engine must be designed to withstand transient speed and temperature conditions which are encountered when sudden changes to the load on the generator, fan, or propeller occur. By adding a relatively small motor/generator to the gas generator spool of the gas turbine engine, the compressor speed and airflow can be quickly adjusted to compensate for external load changes. This reduces the severity and duration of the transient conditions, resulting in decreased operation and reliability problems such as overspeed, compressor surge, and high turbine temperature. The motor/generator may also be used as an engine starting device.

Abstract: A permanent magnet generator generates a variable voltage/variable frequency electric current to power electric induction motors. These motors, in turn, may be used to power electric motor driven engine accessories. The permanent magnet generator is powered directly by a gas turbine engine. A ratio of the variable voltage to the variable frequency remains substantially constant throughout all operating conditions of the gas turbine engine. The relationship of engine speed to accessory speed will remain fixed as the engine speed varies, similarly to the relationship realized when a gearbox was employed. The resulting power system is useful in supplying power from a gas turbine engine to various induction motor driven accessories in aircraft, ground based vehicles, and the like, particularly when the engine has no gearbox. The power system requires no motor controllers and may be used to supply any induction motor driven equipment, including equipment which is not traditionally engine or gearbox mounted.