Aircraft propulsion unit
An aircraft propulsion unit includes an electric motor, at least one accessory unit used for operating the electric motor, an inverter module, the inverter module including a plurality of inverters for powering the electric motor and the at least one accessory unit, and a cooling system coupled to the electric motor and the inverter module, the cooling system comprising a coolant path for circulating a coolant through or adjacent to the electric motor and the at least one accessory unit.
1. An aircraft propulsion unit, comprising:
an electric motor;
at least one accessory unit used for operating the electric motor, the at least one accessory unit comprising a tilt mechanism for tilting the aircraft propulsion unit between a vertical flight configuration and a horizontal flight configuration;
an inverter module, the inverter module including a plurality of inverters for powering the electric motor and the at least one accessory unit; and
a cooling system coupled to the electric motor and the inverter module, the cooling system comprising a coolant path for circulating a coolant through or adjacent to the electric motor and the inverter module.
2. The aircraft propulsion unit of claim 1 wherein the inverter module is at least partly nested in the electric motor.
3. The aircraft propulsion unit of claim 1 wherein the inverter module comprises one or more cold plates for transferring heat from the plurality of inverters to the coolant in the coolant path.
4. The aircraft propulsion unit of claim 1 wherein the at least one accessory unit comprises a pump for circulating the coolant through the coolant path.
5. The aircraft propulsion unit of claim 4 wherein the cooling system includes a radiator and the pump includes a fan for blowing air through the radiator.
6. The aircraft propulsion unit claim 1 wherein the cooling system includes a radiator, airflow through the radiator being greater in use when the aircraft propulsion unit is in the vertical flight configuration than when the aircraft propulsion unit is in the horizontal flight configuration.
7. The aircraft propulsion unit of claim 1 wherein the at least one accessory unit comprises a blade pitching mechanism to adjust the pitch of a rotor blade.
8. The aircraft propulsion unit of claim 1 wherein the inverter module includes an inverter module housing, the inverter module housing including cooling fins for transferring heat from the inverter module.
9. The aircraft propulsion unit of claim 1 wherein the inverter module comprises an inverter module housing, the inverter module housing including a first region and a second region that is separated from the second region, the first region and the second region including redundant inverters.
10. The aircraft propulsion unit of claim 9 wherein the first and second regions are separated by a firewall.
11. The aircraft propulsion unit of claim 1 wherein the motor comprises a stator and a rotor arranged around an axis of rotation of the motor, the inverter module being located inward of the stator and the rotor, wherein the inverter module comprises a plurality of circuit boards, the plurality of circuit boards being in a stacked configuration perpendicular to the axis of rotation of the motor.
12. An aircraft, comprising:
a fuselage;
one or more thrust-generating units; and
one or more propulsion units for driving the thrust-generating units, each propulsion unit comprising:
an electric motor;
at least one accessory unit used for operating the electric motor, the at least one accessory unit comprising a tilt mechanism for tilting the aircraft propulsion unit between a vertical flight configuration and a horizontal flight configuration;
an inverter module, the inverter module including a plurality of inverters for powering the electric motor and the at least one accessory unit; and
a cooling system coupled to the electric motor and the inverter module, the cooling system comprising a coolant path for circulating a coolant through or adjacent to the electric motor and the inverter module, the cooling system further including a radiator, airflow through the radiator being greater in use when the aircraft propulsion unit is in the vertical flight configuration than when the aircraft propulsion unit is in the horizontal flight configuration.
13. The aircraft of claim 12 wherein the inverter module is at least partly nested in the electric motor.
14. The aircraft of claim 12 wherein the at least one accessory unit comprises a blade pitching mechanism to adjust the pitch of a rotor blade.
15. The aircraft of claim 12 wherein the inverter module comprises an inverter module housing, the inverter module housing including a first region and a second region that is separated from the second region, the first region and the second region including redundant inverters.
16. A method of cooling an aircraft propulsion unit comprising an electric motor, at least one accessory unit used for operating the electric motor, and an inverter module, the inverter module including a housing and plurality of inverters for powering the electric motor and the at least one accessory unit, the method comprising:
circulating a coolant through a coolant path defined in the electric motor;
circulating the coolant through the housing of the inverter module;
circulating the coolant through a heat exchanger; and
tilting the aircraft propulsion unit between a horizontal flight configuration and a vertical flight configuration such that airflow through the heat exchanger is increased in the vertical flight configuration.
17. The method of claim 16 wherein the inverter module comprises one or more cold plates for transferring heat from the plurality of inverters to the coolant in the coolant path, the method further comprising circulating the coolant past the one or more cold plates.