A gas turbine engine for an aircraft comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine; a combustion system comprising a fuel metering unit; and an engine controller configured to, in response to a change of a throttle lever angle setting indicative of an acceleration event, increase fuel flow to the combustion system by the fuel metering unit, and to operate the first electric machine in a motor mode to increase the HP spool rotational speed and engine core mass flow.

A gas turbine engine/generator arrangement including a generator, a low-pressure spool operably connected to the generator, a high-pressure spool operably connected to the low-pressure spool, and an electric motor. The electric motor is mechanically connected to the high-pressure spool and is electrically connected to the generator to communicate mechanical rotation between the electric motor and the high-pressure spool. Auxiliary power units and methods of generating electric power are also described.

A gas turbine engine for an aircraft comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine; a combustion system comprising a fuel metering unit; and an engine controller configured to, in response to a change of a throttle lever angle setting indicative of an acceleration event, increase fuel flow to the combustion system by the fuel metering unit, and to operate the first electric machine in a motor mode to increase the HP spool rotational speed and engine core mass flow.

A first line-to-line terminal voltage of a three-phase electric motor is measured while the three-phase electric motor free-spins. A second line-to-line terminal voltage of a three-phase electric motor is measured while the three-phase electric motor free-spins. A motor's rotor position is determined based on the first line-to-line terminal voltage and the second line-to-line terminal voltage. Three-phase current is sent to the motor after the rotor position has been determined. The three-phase current being in-phase with the rotor position.

A method of adjusting a fuel flow rate in a turbine engine propelling an aircraft, including: obtaining a first estimate of a flow rate of fuel injected into a combustion chamber of the turbine engine propelling an aircraft and as delivered by a fuel metering device of the turbine engine; obtaining a second estimate of the fuel flow rate, which second estimate is more accurate than the first estimate for at least one range of fuel flow rate values and being delivered by an estimator device having a flow meter; and adjusting the fuel flow rate threshold value with help of a difference evaluated between the first estimate and the second estimate, the threshold value being for use in an open loop for regulating the turbine engine.

A first line-to-line terminal voltage of a three-phase electric motor is measured while the three-phase electric motor free-spins. A second line-to-line terminal voltage of a three-phase electric motor is measured while the three-phase electric motor free-spins. A motor's rotor position is determined based on the first line-to-line terminal voltage and the second line-to-line terminal voltage. Three-phase current is sent to the motor after the rotor position has been determined. The three-phase current being in-phase with the rotor position.

A turbomachine may include a high-pressure turbine connected to a high-pressure shaft and a low-pressure turbine connected to a low-pressure shaft, the hot gases leaving the high-pressure turbine driving the low-pressure turbine. A method for regulating the turbomachine includes electrically assisting the high-pressure shaft in order to provide said high-pressure shaft with electrical energy in addition to thermal energy obtained from a combustion chamber of the turbomachine, for an assistance period, and correcting the speed of the low-pressure shaft to achieve a reference speed of the low-pressure shaft that was previously determined in the absence of electrical assistance.

A hybrid-electric propulsion (HEP) system is provided that includes a gas turbine engine, an electrical power motive system, a system controller, and a propulsor. The gas turbine engine has a free turbine configuration and a compressor. The electrical power motive system has first and second electric motors and first and second inverters. The gas turbine engine provides motive force to the propulsor. The first electric motor is configurable in a drive mode or in generator mode. The second electric motor is in communication with the compressor. The system controller is in communication with the gas turbine engine, the first and second inverters, and a non-transitory memory storing instructions, which instructions cause the system controller to control the second inverter to operate the second electric motor to provide a motive force to the compressor of the gas turbine engine during a low power setting of the gas turbine engine.

A turbomachine may include a high-pressure turbine connected to a high-pressure shaft and a low-pressure turbine connected to a low-pressure shaft, the hot gases leaving the high-pressure turbine driving the low-pressure turbine. A method for regulating the turbomachine includes electrically assisting the high-pressure shaft in order to provide said high-pressure shaft with electrical energy in addition to thermal energy obtained from a combustion chamber of the turbomachine, for an assistance period, and correcting the speed of the low-pressure shaft to achieve a reference speed of the low-pressure shaft that was previously determined in the absence of electrical assistance.