Abstract: Integrated arrangements of electrical machines and power electronics converters are described. One such arrangement comprises: an electrical machine comprising one or more windings; a power electronics converter arranged to supply current to or receive current from the one or more windings of the electrical machine; a magnetocaloric effect (MCE) material in thermal contact with the power electronics converter; and a heat sink for removing heat from the MCE material. The MCE material is arranged in proximity to the one or more windings of the electrical machine whereby, in use, stray magnetic flux from the windings of the electrical machine passes through the MCE material and activates the MCE material. The repeated application and removal of the stray flux during normal operation of the electrical machine creates cycles of magnetic refrigeration, which removes heat from the power electronics converter.

Abstract: The disclosure relates to an electrical power system for connecting an electrical machine to first and second DC networks operating at different voltages. Example embodiments include an electrical power system comprising: an electrical machine having first and second pluralities of windings; a first AC:DC power electronics converter connected to the first plurality of windings; a second AC:DC power electronics converter connected to the second plurality of windings; a switching controller configured to provide switching signals to the first and second AC:DC power electronics converters to provide a first DC supply at a DC side of the first AC:DC power electronics converter and a second DC supply at a DC side of the second AC:DC power electronics converter.

Abstract: An electrical power system for an aircraft includes a DC:AC power electronics converter and a transverse flux electrical machine. The transverse flux electrical machine includes a rotor that is coupleable to a rotating shaft of a propulsor of the aircraft, wherein the rotor includes a plurality of permanent magnets defining a number, NP, of evenly distributed rotor poles. The transverse flux electrical machine further includes a stator arranged to interact with the rotor, such that a torque is produced. The stator includes a plurality of coils.

Abstract: An electrical propulsion unit (EPU) for a vertical take-off and landing (VTOL) aircraft is provided. The EPU includes a propeller or a fan and an electric motor. The electric motor includes a stator comprising coils configured to carry current and a rotor arranged to interact with the stator. The rotor is configured to generate a torque for driving rotation of the propeller or the fan. The coils of the stator have a cumulated conductor volume Vconductor The stator, the rotor, or the stator and the rotor include a flux guiding iron material configured to guide magnetic flux generated by the coils of the stator, wherein the flux guiding iron material has a cumulated iron volume Viron, and wherein the electric motor has a machine parameter ? that is greater than or equal to 0.25, ? being defined as: ?=Vconductor/Viron.

Abstract: The disclosure relates to an electric aircraft propulsion assembly for an electric vertical takeoff and landing, eVTOL, aircraft, the assembly comprising: an electric storage unit; a first electric motor connected to power a first propulsor; a first converter configured as a DC:AC converter for driving the first electric motor and a second electric motor connected to power a second propulsor, a second converter. A controller is connected to control operation of the first and second converters and is configured to operate in a first mode in which the first and second converters are operated as DC:AC converters to drive the first and second electric motors and a second mode in which the first converter is operated to drive the first electric motor to power the first propulsor and the second converter is operated to drive the second electric motor to provide a braking torque on the second propulsor.

Abstract: The disclosure relates to an electric aircraft propulsion assembly comprising: an electric storage unit; a first electric motor connected to power a first propulsor; a first converter configured as a DC:AC converter having input connections connectable to the electric storage unit and output connections connected across the first electric motor, the first converter configured as a DC:AC converter; a second electric motor connected to power a second propulsor; a second converter connected between the first converter input connections and the second electric motor; and a controller configured to control operation of the first and second converters, wherein the second converter is operable as a DC:AC converter to convert the DC supply from the electric storage unit to an AC supply across the second electric motor and as a DC:DC converter to convert the DC supply from the electric storage unit at a first DC level to a DC supply at the input connections of the first converter at a second DC level.

Abstract: An electric machine comprises a stator winding located within a stator housing. The stator housing comprises an inlet chamber configured to communicate with a supply of coolant, and an outlet. The stator housing contains a baffle configured to separate the stator winding and outlet from the inlet chamber. The baffle includes at least one aperture therethrough configured to supply an impingement flow of coolant to the stator winding.

Abstract: An AC to DC conversion device has first and second AC input terminals arranged to be coupled respectively to first and second terminals of a phase of an AC current generator, an H-bridge rectification device comprising two pairs of diodes, each pair being coupled to a respective one of the AC terminals to produce a DC output comprising a rectified back EMF waveform, and a waveform generator. The waveform generator comprises an output coupled to the DC output of the H-bridge rectification device, and is configured to input a unidirectional waveform to the DC output having the same magnitude and fundamental frequency as the rectified back EMF, phase shifted by a predetermined angle relative to the rectified back EMF waveform.

Abstract: A radial flux rotary electric machine having an exterior-rotor configuration is shown. The machine has a permanent-magnet rotor comprising permanent magnets in a Halbach array, and an air-cored stator interior to the rotor having teeth defining tapered slots and distributed windings around the teeth to form coils in a double-layer arrangement, the windings being comprised of a plurality of phase windings. For each tooth T having a slot S1 on one side thereof and a slot S2 on another side thereof, a coil side C1 of a phase winding is arranged to occupy a radially inner layer of the slot S1 and a coil side C2 of the same phase winding is arranged to occupy a radially outer layer of the slot S2, wherein the coil side C1 has a smaller circumferential dimension and a larger radial dimension than the coil side C2.

Abstract: Integrated arrangements of electrical machines and power electronics converters are described. One such arrangement comprises: an electrical machine comprising one or more windings; a power electronics converter arranged to supply current to or receive current from the one or more windings of the electrical machine; a magnetocaloric effect (MCE) material in thermal contact with the power electronics converter; and a heat sink for removing heat from the MCE material. The MCE material is arranged in proximity to the one or more windings of the electrical machine whereby, in use, stray magnetic flux from the windings of the electrical machine passes through the MCE material and activates the MCE material. The repeated application and removal of the stray flux during normal operation of the electrical machine creates cycles of magnetic refrigeration, which removes heat from the power electronics converter.

Abstract: The dual rotor electric machine comprises: a stator having one or more slots and one or more stator windings. The dual rotor electric machine further comprises a first rotor arranged to rotate relative to the stator with an airgap therebetween. The first rotor comprises a first rotor excitation element having one or more magnetic pole pairs arranged to interact with the stator windings, the first rotor configured to rotate about an axis (X). The dual rotor electric machine further comprises a second rotor arranged to rotate relative to the stator with an airgap therebetween. The second rotor comprises a second rotor excitation element having one or more magnetic pole pairs arranged to interact with the stator windings, the second rotor being configured to rotate about the axis (X).

Abstract: An electric machine (101) for use in an aircraft is shown. The electric machine comprises a casing (104) containing electromechanical components, a shaft (106) which extends outside of the casing, a seal (107) to seal the casing around the shaft, and a pressurisation system (102) configured to pressurise the casing above an external pressure to prevent electrical breakdown within gas in the casing.

Abstract: An electric machine (212) comprises a turbomachine rotor (203) having a hub (302) and an axis of rotation (A-A) about which the turbomachine rotor is arranged to rotate. The turbomachine rotor includes a plurality of blades (301). Each blade has a root (303) attached to the hub, a tip (304) remote from the hub, a leading edge (305) and a trailing edge (306), a pressure side and a suction side (307). A stator (502) is located circumferentially around the turbomachine rotor. Each blade further comprises a rotor element at the tip comprising a permanent magnet having a first pole (401) and a second pole (402), the first pole being located adjacent the suction side of the blade and the second pole being located adjacent the pressure side such that a magnetic flux path extends perpendicularly through the blade tip.

Abstract: An electromechanical system comprising: a rotor comprising a plurality of teeth spaced about a circumference of the rotor, wherein the teeth of the rotor are equally spaced about the rotor according to a tooth spacing angle, and are skewed in an axial direction such that the circumferential positions of the teeth of the rotor vary along the axial length of the rotor, and first and second stator segments, each extending partway about the rotor and comprising a field winding and poles arranged to magnetically interact with the teeth of the rotor such that an alternating current (AC) back-emf is induced in the field winding upon rotation of the rotor. The poles of the first stator segment are angularly displaced about the rotor from the poles of the second stator segment such that the back-emf induced in the field winding of the first stator segment is phase shifted with respect to the back-emf induced in the field winding of the second stator segment.

Abstract: Disclosed herein is a converter for converting an AC voltage to a DC voltage, the converter comprising: a first H-bridge circuit comprising a first AC terminal for receiving an AC voltage, a second AC terminal, a first DC terminal and a second DC terminal; a second H-bridge circuit comprising a first AC terminal for receiving an AC voltage, a second AC terminal, a first DC terminal and a second DC terminal; an isolation block arranged between the second AC terminal of the first H-bridge circuit and the second AC terminal of the second H-bridge circuit; and a DC voltage output of the converter with a first terminal and a second terminal; wherein: the first terminal of the DC voltage output is connected to the first DC terminal of the first H-bridge circuit and the first DC terminal of the second H-bridge circuit; and the second terminal of the DC voltage output is connected to the second DC terminal of the first H-bridge circuit and the second DC terminal of the second H-bridge circuit.

Abstract: An electrical converter (203) having an active diode-clamped multilevel topology is shown. Each clamping diode is connected in antiparallel with a switch (S5A, S5B). The converter comprises polyphase supply phases (A, B, C) each of which are connected via a respective phase leg (401, 402, 403) to dc rails (301, 302) and a dc-link capacitor. The dc-link capacitor includes a plurality of series-connected capacitors (404, 405). A controller is configured to, in response to an event signal, for each phase leg, activate a combination of switches therein to form a pair of parallel conduction paths to a midpoint (406) between two capacitors in the dc-link capacitor, thereby connecting each phase to the same node.

Abstract: An electrical machine has a variable reluctance rotor, and a stator formed as an annular array of stator segments. The reluctance of the rotor-to-stator magnetic flux path varies with rotor position whereby the stator segments are magnetically energizable to rotate the rotor. The stator segments are arranged in the array such that, when energized to rotate the rotor, they produce an unbalanced force on the rotor. The machine further has a compensator including one or more balancing segments which are configured to be magnetically energizable to produce a balancing force on the rotor which balances the unbalanced force. The reluctance of the rotor-to-compensator magnetic flux path is substantially invariant with rotor position.

Abstract: An electrical machine comprising a two-part rotor formed of a first rotor part and a second rotor part. The first rotor part includes a conical section and is mounted to a shaft of the machine. The second rotor part has a bore including a complementary conical section. The second rotor part is configured to displace axially between a first state, in which it is engaged with the first rotor part to form the rotor of the electrical machine, and a second state, in which it is axially disengaged from the first rotor part. Also a clutch having an engaged state and a disengaged state. When the clutch is in one of its states the second rotor part is in its first state and switching the clutch to the other of its states axially displaces the second rotor part to its second state.

Abstract: A synchronous electrical machine includes a stator having a circumferential row of teeth carrying stator windings. The electrical machine further includes a coaxial rotor having a circumferential row of poles carrying field windings. Each pole has first and second side flanks and a tip surface which extends continuously there between to form an air gap to the teeth of the stator. On a transverse cross-section through the machine, one of the side flanks forms a leading edge of the pole, and the other side flank forms an opposite, trailing edge of the pole. Each pole carries a row of permanent magnets which extends across the tip surface from one of the side flanks to the other side flank, the permanent magnets compensating for armature magnetic reaction. The radial thickness of the permanent magnets increases smoothly with progressive distance across the tip surface from one of the side flanks to the other side flank.

Abstract: A vehicle propulsion system comprises a first propulsor and a second propulsor. The first and second propulsors are coupled to an electric machine comprising a stator and first and second rotors. Each of the first and second rotors are electromagnetically coupled to the stator. The first rotor is coupled to the first propulsor and the second rotor is coupled to the second propulsor.