Abstract: Electrical power systems for distributing electrical power in arrangements including one or more gas turbine engines; one such system includes: one or more rotary electric machines, coupled to a gas turbine engine spool; converter circuits connected to the rotary electric machines converting between alternating current (ac) and direct current (dc), wherein the rotary electric machines and the converter circuits output a number R?2 of dc power channels, each channel having an index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein each dc load channel has an index n=(1, . . . , N) and R<N?2R.

Abstract: Electrical systems for connecting rotary electric machines to dc networks operating at different voltages V and W where V>W along with gas turbine engine arrangements incorporating such systems.

Abstract: An electrical system for connecting a rotary electric machine to dc networks operating at different voltages, the electric machine having polyphase winding sets each having a respective index. The electrical system has a first set of ac-dc converter circuits connected in a modular multilevel configuration, each ac-dc converter circuit having a respective index and an ac interface for connection with a corresponding winding set, and in which the modular multilevel configuration has dc outputs each having a respective index. The electrical system also has a set of dc-dc converter circuits each having a respective index and being configured to convert dc power between a voltage at a first dc interface and a voltage at a second dc interface, where a first dc interface of the nth dc-dc converter circuit is connected with the dc outputs of the modular multilevel configuration.

Abstract: An electrical system having a first dual-wound rotary electric machine mechanically coupled with a first gas turbine spool and having a first three-phase sub-machine and a second three-phase submachine; a second dual-wound rotary electric machine mechanically coupled with a second gas turbine spool and having a third three-phase sub-machine and a fourth three-phase submachine; and a set of N = 4 bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc), each of which has an associated index n = (1, ... , N), and for all n, the ac side of the nth bidirectional converter circuit is connected with the nth three-phase sub-machine. The dc side of the first converter circuit is connected with the dc side of the third converter circuit, and the dc side of the second converter circuit is connected with the dc side of the fourth converter circuit.

Abstract: Electrical power systems for distributing electrical power in aircraft are described. One such electrical power system comprises: an electrical power source configured to output a number R?2 of dc power channels, each dc power channel having a respective index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein each dc load channel has a respective index n=(1, . . . , N) and R<N?2R. The switching arrangement is operable to connect the r-th power channel to the n-th load channel according to a relationship r(n).

Abstract: Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system includes: a first rotary electric machine; a second rotary electric machine; a first set of bidirectional converter circuits; a second set of bidirectional converter circuits; and DC outputs for connection with an R-channel network. Each electrical machine is mechanically coupled with a respective gas turbine spool and has an identical even number N?4 of phases, each phase having a respective index and including an identical number P?1 of coils wound in a P-plex configuration in which adjacent phases are radially separated by 2?/NP mechanical radians. Each of the first and second converter circuits converts AC to and from DC, has a respective index n, and is connected with the P coils in the nth phase of the first and second rotary electric machines, respectively.

Abstract: Electrical power system includes: one or more rotary electric machines, each mechanically coupled to a gas turbine engine spool; a set of converter circuits connected to the one or more rotary electric machines for conversion between alternating (ac) and direct current (dc), wherein one or more rotary electric machines and the set of converter circuits are arranged to output a number R?2 of dc power channels, each dc power channel having a respective index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein N>R and each dc load channel has a respective index n=(1, . . . , N). The switching arrangement is operable to connect a number Q?1 of the N load channels to at least two different power channels of the R power channels.

Abstract: Electrical power systems for distributing electrical power in aircraft are described. One such electrical power system comprises: an electrical power source configured to output a number R?2 of dc power channels, each dc power channel having a respective index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein N>R and each dc load channel has a respective index n=(1, . . . , N). The system further comprises, for each respective one of a plurality of the N load channels, a current limiting device (CLD) operable to limit an amount of current flowing from the power channels to a load connectable to the electrical power system via the respective load channel. The electrical power source may comprise one or more batteries.

Abstract: Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system comprises: a first rotary electric machine mechanically coupled with a first gas turbine spool and a second rotary electric machine mechanically coupled with a second gas turbine spool, each said electric machine having an identical even number N?4 of phases, each phase having a respective index n=(1, . . .

Abstract: Gas turbine engines and methods of starting gas turbine engines, the gas turbine engine including: an electronic engine controller; one or more spools designated a starting spool for starting the engine, and has a required starting torque ?s; a permanent magnet alternator mechanically coupled with the starting spool, the alternator, in a motor mode, provides a peak torque of ?a, and, in a generator mode, generates electrical power for the electronic engine controller; and an electrical starter-generator mechanically coupled with the starting spool. The starter-generator in a motor mode, provides a peak torque of ?sg, and, in a generator mode, generates electrical power for an external load. ?sg+?a??s and ?sg, ?a<?s, and the electronic engine controller, during a start procedure, operates both the permanent magnet alternator and the starter-generator in a motor mode to drive the starting spool.

Abstract: A power electronics unit for an aircraft and a method of determining the integrity of a power electronics unit are provided. The power electronics unit comprises an electric machine controller; a heatsink arranged to conduct heat from the electric machine controller; a housing comprising a sealed internal volume enclosing the electric machine controller and heatsink; a dielectric liquid partially filling the internal volume to cover the electric machine controller; a gas pocket within the internal volume; a pressure sensor arranged to measure a pressure of gas within the gas pocket; a temperature sensor arranged to measure a temperature within the internal volume; and a controller. The controller is configured to receive signals from the pressure sensor and temperature sensor, determine a pressure and temperature from the received signals and provide an output signal dependent on the determined temperature and pressure.

Abstract: Electrical power system includes: one or more rotary electric machines, each mechanically coupled to a gas turbine engine spool; a set of converter circuits connected to the one or more rotary electric machines for conversion between alternating (ac) and direct current (dc), wherein one or more rotary electric machines and the set of converter circuits are arranged to output a number R?2 of dc power channels, each dc power channel having a respective index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein N>R and each dc load channel has a respective index n=(1, . . . , N). The switching arrangement is operable to connect a number Q?1 of the N load channels to at least two different power channels of the R power channels.

Abstract: Electrical power systems for distributing electrical power in aircraft are described. One such electrical power system comprises: an electrical power source configured to output a number R?2 of dc power channels, each dc power channel having a respective index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein each dc load channel has a respective index n=(1, . . . , N) and R<N?2R. The switching arrangement is operable to connect the r-th power channel to the n-th load channel according to the relationship: r ? ( n ) = { 1 , n = 1 n 2 ? and ? n 2 + 1 , 1 < n < N ? and ? n = 0 ? ? ( mod ? ? 2 ) n - 1 2 ? and ? n + 1 2 ? , 1 < n < N ? and ? n = 1 ? ? ( mod ? ? 2 ) R , n = N . FIG .

Abstract: Electrical power systems for distributing electrical power in arrangements including one or more gas turbine engines; one such system includes: one or more rotary electric machines coupled to a gas turbine engine spool; a set of converter circuits connected to the rotary electric machines converting between alternating current (ac) and direct current (dc), wherein the rotary electric machines and the converter circuits output a number R?2 of dc power channels, each channel having an index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein N>R and each dc load channel has an index n=(1, . . . , N). For each respective N load channels, a current limiting device (CLD) limits the current flowing from power channels to a load connectable to the electrical power system via the respective load channel.

Abstract: Electrical power systems for distributing electrical power in arrangements including one or more gas turbine engines; one such system includes: one or more rotary electric machines coupled to a gas turbine engine spool; a set of converter circuits connected to the rotary electric machines converting between alternating current (ac) and direct current (dc), wherein the rotary electric machines and the converter circuits output a number R?2 of dc power channels, each channel having an index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein N>R and each dc load channel has an index n=(1, . . . , N). For each respective N load channels, a current limiting device (CLD) limits the current flowing from power channels to a load connectable to the electrical power system via the respective load channel.

Abstract: Electrical power systems for distributing electrical power in arrangements including one or more gas turbine engines; one such system includes: one or more rotary electric machines, coupled to a gas turbine engine spool; converter circuits connected to the rotary electric machines converting between alternating current (ac) and direct current (dc), wherein the rotary electric machines and the converter circuits output a number R?2 of dc power channels, each channel having an index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein each dc load channel has an index n=(1, . . . , N) and R<N?2R.

Abstract: Electrical power systems for distributing electrical power in aircraft are described. One such electrical power system comprises: an electrical power source configured to output a number R?2 of dc power channels, each dc power channel having a respective index r=(1, . . . , R); and a group of N dc load channels connected to the R dc power channels by a switching arrangement, wherein N>R and each dc load channel has a respective index n=(1, . . . , N). The system further comprises, for each respective one of a plurality of the N load channels, a current limiting device (CLD) operable to limit an amount of current flowing from the power channels to a load connectable to the electrical power system via the respective load channel. The electrical power source may comprise one or more batteries.

Abstract: Electrical systems for connecting rotary electric machines to dc networks operating at different voltages V and W where V>W are provided, along with gas turbine engine arrangements incorporating such systems.

Abstract: Gas turbine engines and methods of starting gas turbine engines, the gas turbine engine including: an electronic engine controller; one or more spools designated a starting spool for starting the engine, and has a required starting torque ?s; a permanent magnet alternator mechanically coupled with the starting spool, the alternator, in a motor mode, provides a peak torque of ?a, and, in a generator mode, generates electrical power for the electronic engine controller; and an electrical starter-generator mechanically coupled with the starting spool. The starter-generator in a motor mode, provides a peak torque of ?sg, and, in a generator mode, generates electrical power for an external load. ?sg+?a??s and ?sg, ?a<?s, and the electronic engine controller, during a start procedure, operates both the permanent magnet alternator and the starter-generator in a motor mode to drive the starting spool.

Abstract: An aircraft power generation system having an electrical power generator configured to be driven by a gas turbine engine of the aircraft is provided. The electrical power generator is further configured to be electrically coupled to one or more electrical loads of the aircraft, the electrical power generator being cooled by a coolant sub-system. The cooling performance of the coolant sub-system is affected by the operation of the gas turbine engine. The aircraft power generation system further has a control sub-system configured to dynamically control the electrical output power capability of the generator in accordance with the cooling performance of the coolant sub-system.