A stator winding includes a plurality of conductors including ducts. The ducts can be connected to a heat pipe or a conduit providing a coolant flow to directly cool the winding. The heat pipe can be connected to a heat exchanger that includes a coolant flow. The stator winding can be produced using additive manufacturing, with hollow ducts extending through leg sections and solid end sections. The heat exchanger can also be additively manufactured. A circuit for driving an electrical machine can be in thermal communication with the heat exchanger, such that the thermal system manages both the stators and the drive circuit.

A motor drive architecture is provided. The motor drive architecture includes a three-dimensional (3D) stack of cold plates on which power electronic components for an electric machine are mountable and supporting structures. Each cold plate has an annular shape with internal fluid pathways. The supporting structures hold the cold plates in the 3D stack. At least one supporting structure defines an internal cavity bifurcated into an internal inlet fluid pathway configured to direct fluid into the internal fluid pathways of each cold plate and an internal outlet fluid pathway receptive of the fluid from the internal fluid pathways of each cold plate.

A motor drive architecture is provided. The motor drive architecture includes a three-dimensional (3D) stack of cold plates on which power electronic components for an electric machine are mountable and supporting structures. Each cold plate has an annular shape with internal fluid pathways. The supporting structures hold the cold plates in the 3D stack. At least one supporting structure defines an internal cavity bifurcated into an internal inlet fluid pathway configured to direct fluid into the internal fluid pathways of each cold plate and an internal outlet fluid pathway receptive of the fluid from the internal fluid pathways of each cold plate.

Aircraft electric motors are described. The aircraft electric motors include a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a drive unit configured to drive operation of the motor unit, and a cooling system. The cooling system includes an oscillating heat pipe containing a first working fluid, wherein the oscillating heat pipe is arranged to pick up heat from at least one winding, the oscillating heat pipe having an evaporator section arranged in thermal contact with the at least one winding and a condenser section arranged away from the evaporator section and a heat pickup portion arranged to receive a second working fluid to remove heat from the condenser section of the oscillating heat pipe.

Aircraft electric motors are described. The aircraft electric motors include a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a drive unit configured to drive operation of the motor unit, and a cooling system. The cooling system includes an oscillating heat pipe containing a first working fluid, wherein the oscillating heat pipe is arranged to pick up heat from at least one winding, the oscillating heat pipe having an evaporator section arranged in thermal contact with the at least one winding and a condenser section arranged away from the evaporator section and a heat pickup portion arranged to receive a second working fluid to remove heat from the condenser section of the oscillating heat pipe.

Aircraft electric motors are described. The aircraft electric motors include a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a drive unit configured to drive operation of the motor unit, and a cooling system having at least one directional feature forming a portion of at least one cooling channel, the at least one directional feature configured to prevent backflow of a cooling fluid that passes through the at least one cooling channel.

Aircraft electric motors are described. The aircraft electric motors include a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a drive unit configured to drive operation of the motor unit, and a cooling system having at least one directional feature forming a portion of at least one cooling channel, the at least one directional feature configured to prevent backflow of a cooling fluid that passes through the at least one cooling channel.

Aircraft electric motors are described. The aircraft electric motors includes a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a drive unit configured to drive operation of the motor unit, and a cooling system. The cooling system includes at least one cooling channel integrally formed within at least one winding, wherein the at least one cooling channel comprises an inlet to receive a two-phase cooling fluid and an outlet configured to discharge the two-phase cooling fluid, wherein a cross-sectional area of the at least one cooling channel at the inlet is less than a cross-sectional area of the at least one cooling channel at the outlet.

Aircraft electric motors are described. The aircraft electric motors includes a motor unit having a rotor and a stator, wherein the stator includes a plurality of windings and cooling channels arranged to provide cooling to the plurality of windings, a drive unit configured to drive operation of the motor unit, and a cooling system. The cooling system includes at least one cooling channel integrally formed within at least one winding, wherein the at least one cooling channel comprises an inlet to receive a two-phase cooling fluid and an outlet configured to discharge the two-phase cooling fluid, wherein a cross-sectional area of the at least one cooling channel at the inlet is less than a cross-sectional area of the at least one cooling channel at the outlet.

An electric propulsion system for an aircraft includes a nacelle and an electric machine. The electric machine includes a stator positioned in the nacelle, and a rotor and fan assembly positioned in a primary flow path through the nacelle. The rotor and fan assembly includes a cylindrical fan shroud, a plurality of rotor magnets positioned on an outer surface of the fan shroud, and a fan hub mounted on a central support shaft via one or more bearings. A plurality of fan blades extend between an inner surface of the fan shroud and an outer surface of the fan hub. The rotor magnets may be loaded in compression in a radial direction when the rotor and fan assembly is at rest. The fan blades may be pre-stressed in a radial direction when the rotor and fan assembly is at rest.