DISTRIBUTED PROPULSION SYSTEM AND METHOD OF CONTROL

• US 20130094963A1
• Filed: 10/04/2012
• Published: 04/18/2013
• Est. Priority Date: 10/13/2011
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: ROLT, Andrew Martin
• Granted Patent: US 9,376,213 B2
• Time in Patent Office: Days
• US Class Current: 416/1
• CPC Class Codes: B64D 27/02 Aircraft characterised by the type or position of power plants fuselages specially adapted for mounting power plants B64C1/16; wings specially adapted for power plants B64C3/32
• CPC Class Codes: B64D 27/24 using steam or spring force jet aircraft B64D27/16
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

This invention relates to a method and apparatus for controlling power distribution in an electrical aircraft propulsive system having at least one electrical propulsion unit which includes a plurality of rotatable blades, each blade having an adjustable pitch; a pitch adjusting mechanism for adjusting the pitch of the blades; at least one electrical machine electrically connected to the electrical propulsion unit so as to provide electrical power when in use; and, a control system, the method comprising the steps of: determining the required propulsion; determining whether the propulsive units are delivering the required propulsion; and, adjusting the pitch angle of the blades of at least one propulsive unit so as to increase or decrease the propulsion provided by that propulsive unit.

Claims

1. A method of controlling power distribution in an electrical aircraft propulsive system having at least one electrical propulsion unit which includes a plurality of rotatable blades on a rotor, each blade having an adjustable pitch;

a pitch adjusting mechanism for adjusting the pitch of the blades;

at least one electrical machine electrically connected to the electrical propulsion unit so as to provide electrical power when in use; and

, a control system, the method comprising the steps of;

determining the required propulsion;

determining whether the propulsive units are delivering the required propulsion; and

,

adjusting the pitch angle of the blades of at least one propulsive unit so as to increase or decrease the propulsion provided by that propulsive unit.

2. A method of controlling power distribution in an electrical aircraft propulsive system as claimed in claim 1 wherein the step of determining whether the propulsive units are delivering the required propulsion comprises:

monitoring the rotational state and pitch angle of the rotatable blades;

determining whether the rotational state is within a predetermined range.

3. A method of controlling power distribution in an electrical aircraft propulsive system as claimed in claim 2 wherein monitoring the rotational state includes monitoring the angular position of the blades and determining either or both of the rotational speed and angular acceleration of the rotatable blades.

4. A method of controlling power distribution in an electrical aircraft propulsive system as claimed in claim 1 further comprising the step of:

determining whether there are parasitic oscillations in the rotation of the blades and adjusting the pitch of the blades to damp the oscillations.

5. A method of controlling power distribution in an electrical aircraft propulsive system as claimed in claim 4, wherein the determining whether there are parasitic oscillations includes the step of monitoring the acceleration and deceleration of the rotor.

6. A method of controlling power distribution in an electrical aircraft propulsive system as claimed in claim 1 further comprising adjusting the pitch of the blades such that the propulsive unit generates electrical energy for the electrical network.

7. A method of controlling power distribution in an electrical aircraft propulsive system as claimed in claim 4 wherein only a portion of the propulsive units are used to act as dampers.

8. An electrical propulsion system for an aircraft, comprising:

at least one electrical propulsion unit having a plurality of rotatable blades, each blade having an adjustable pitch;

a pitch adjustment mechanism for adjusting the pitch of the blades;

at least one electrical machine electrically connected to propulsion unit so as to provide electrical power in use; and

,

a control system configured to determine the required propulsion and propulsion being delivered by the propulsion system and adjust the pitch of the blades of at least one propulsion unit as to increase or decrease the propulsion provided by that unit.

9. An electrical propulsion system for an aircraft as claimed in claim 8, wherein the control system is configured to monitor the rotational state and pitch angle of the rotatable blades and determine whether the rotational state is within a predetermined range.

10. An electrical propulsion system for an aircraft as claimed in claim 9, wherein monitoring the rotational state includes monitoring the angular position of the blades and determining either or both of the rotational speed and angular acceleration of the rotatable blades.

11. An electrical propulsion system for an aircraft as claimed in claim 8, wherein control system is further configured to determine whether there are parasitic oscillations in the rotation of the blades and issue a control signal to the pitch adjustment mechanism to adjust the pitch of the blades so as to damp the oscillations.

12. An electrical propulsion system for an aircraft as claimed in claim 8, wherein the control system comprises a central control system for controlling the distribution of power between the propulsion units and a secondary control units at each of the plurality of propulsive units, the secondary control units for determining whether the propulsive units are operating within predetermined rated limits.

13. An electrical propulsion system for an aircraft as claimed in claim 8 wherein in the electrical propulsion unit and electrical machine each include a plurality of poles, and the ratio of the poles is such that the propulsion unit and electrical machine can rotate at different rotational speeds for the same alternating current frequency while the pole passing frequency remains synchronised.