Drive system for an aircraft

Abstract

Drive system for an aircraft, including: a propeller; electric motor; transmission system for transmitting positive torque from the motor to drive the propeller and negative torque from the propeller in windmill braking state to drive the motor; interface for inputting an input; first unit for controlling torque acting on the motor; second unit for detecting rotational speed of the motor; selection unit to select an active mode from propulsion mode and recovery mode, wherein the motor generates recovery energy in the recovery mode; and management system to control energy flow in an electrical system of the aircraft, the electrical system including the motor, is controlled according to the active mode; wherein the selection unit is configured to select the active mode according to the input, rotational speed, and predefined envelope, wherein the envelope indicates a maximum positive torque and minimum negative torque that depends on the rotational speed.

Claims

1. A drive system for an aircraft, the system comprising: a propeller P having propeller blades; an electric motor E; a transmission system to mechanically transmit a positive torque T.sub.+ from the electric motor E to drive the propeller P and to transmit a negative torque T.sub.− from the propeller P in a windmill braking state to drive the electric motor E; a first input interface to input an input IN1 that defines power to be output by the electric motor E to drive the propeller P; an electronic controller to control a torque T acting on the electric motor E, where Tϵ{T.sub.−, 0, T.sub.+} and T.sub.−≤0 and T.sub.+≥0; a speed sensor to detect a rotational speed RPM.sub.E of the electric motor E; an electronic selector to select an active mode AM from a propulsion mode PM and a recovery mode RM, where AMϵ{PM, RM}, wherein in the recovery mode RM the electric motor E generates electrical recovery energy E.sub.recup from the negative torque T.sub.− transmitted by the transmission system from the propeller P; and an energy management system to control electrical energy flow in an electrical system of the aircraft, the electrical system comprising the electric motor E, according to the active mode AM; wherein the electronic selector is configured such that the active mode AM is selected automatically according to the input IN1, the rotational speed RPM.sub.E of the electric motor E, and a predefined envelope, wherein the predefined envelope indicates a maximum positive torque Max(T.sub.+) and a minimum negative torque Min(T.sub.−(RPM.sub.E)) that depends on the rotational speed RPM.sub.E of the electric motor E, or respective values that depend on same, wherein, for the torque T acting on the electric motor E, T=T(IN1,RPM.sub.E)ϵ[Min(T.sub.−(RPM.sub.E)), . . . , Max(T.sub.+)].

2. The drive system according to claim 1, wherein the input IN1 represents a percentage P: P(IN1)ϵ[0% . . . 100%], and the electronic selector is configured such that the recovery mode RM is selected as the active mode AM, when the percentage P(IN1) in relation to a value range [Min(T.sub.−(RPM.sub.E)), . . . , MAX(T.sub.+)] represents a negative torque T(IN1,RPM.sub.E), for which T.sub.−=T(IN1,RPM.sub.E)<0 and/or T(IN1,RPM.sub.E)<T.sub.−*, where T.sub.−*<0 indicates a limit for the negative torque T.sub.−, and where P(IN1)=0% represents Min(T.sub.−(RPM.sub.E)) and P(IN1)=100% represents MAX(T.sub.+).

3. The drive system according to claim 1, wherein the system comprises a torque sensor to detect the torque T acting on the electric motor E.

4. The drive system according to claim 3, wherein the electronic controller is configured to control a negative torque T=T.sub.− acting on the electric motor E according to at least one from the following list: an energy content of a battery connected to the electric motor E, a charging current to a battery connected to the electric motor E, a predefined minimum and/or maximum of the charging current, a temperature of the electric motor E and/or a battery, a predefined minimum and/or maximum of the temperature, a state of the electric motor E and/or the battery, a predefined minimum and/or maximum of the state, a current and/or a predefined speed of the aircraft, a predefined minimum and/or maximum of the speed, a current and/or predefined sink rate of the aircraft, a predefined minimum and/or maximum of the sink rate, from the input IN1, a rotational speed of the propeller P and/or of the electric motor E, a predefined minimum and/or maximum of the rotational speed, a currently generated electrical recovery energy E.sub.recup, a predefined minimum and/or maximum of the currently generated electrical recovery energy E.sub.recup, a current torque T transmitted from the propeller P to the electric motor E, a predefined minimum and/or maximum of the current torque T, a flight altitude and outside temperature, and an angle of attack of the propeller blades.

5. The drive system according to claim 4, wherein the electronic controller is configured to control the torque T acting on the electric motor E by adjusting the electrical energy flow to/from the electric motor E and/or by adjusting the angle of attack of the propeller blades of the propeller P.

6. The drive system according to claim 1, wherein the system comprises a sink for the electrical recovery energy E.sub.recup and/or a storage for the electrical recovery energy E.sub.recup, wherein the sink and/or the storage are connected to the energy management system, and wherein the energy management system is configured to control usage of the electrical recovery energy E.sub.recup with respect to the sink and/or the storage.

7. The drive system according to claim 1, wherein the system comprises a display unit, the display unit configured to display one or more of the following information: information about the negative torque T.sub.− with which the electric motor E is driven, a parameter that depends on the negative torque T.sub.−, information about a positive torque T.sub.+ with which the propeller P is driven by the electric motor E, a parameter that depends on the positive torque T.sub.+, information about a current mode AM, and a currently generated electrical recovery energy E.sub.recup or a quantity derived from the currently generated electrical recovery energy E.sub.recup.

8. An aircraft comprising a drive system, the drive system comprising: a propeller P having propeller blades; an electric motor E; a transmission system to mechanically transmit a positive torque T.sub.+ from the electric motor E to drive the propeller P and to transmit a negative torque T.sub.− from the propeller P in a windmill braking state to drive the electric motor E; a first input interface to input an input IN1 that defines power to be output by the electric motor E to drive the propeller P; an electronic controller to control a torque T acting on the electric motor E, where Tϵ{T.sub.−, 0, T.sub.+} and T.sub.−≤0 and T.sub.+≥0; a speed sensor to detect a rotational speed RPM.sub.E of the electric motor E; an electronic selector to select an active mode AM from a propulsion mode PM and a recovery mode RM, where AMϵ{PM, RM}, wherein in the recovery mode RM the electric motor E generates electrical recovery energy E.sub.recup from the negative torque T.sub.− transmitted by the transmission system from the propeller P; and an energy management system to control energy flow in an electrical system of the aircraft, the electrical system comprising the electric motor E, according to the active mode AM; wherein the electronic selector is configured such that the active mode AM is selected automatically according to the input IN1, the rotational speed RPM.sub.E of the electric motor E, and a predefined envelope, wherein the predefined envelope indicates a maximum positive torque Max(T.sub.+) and a minimum negative torque Min(T.sub.−(RPM.sub.E)) that depends on the rotational speed RPM.sub.E of the electric motor E, or respective values that depend on same, wherein, for the torque T acting on the electric motor E, T=T(IN1,RPM.sub.E)ϵ[Min(T.sub.−(RPM.sub.E)), . . . , Max(T.sub.+)].

9. The aircraft according to claim 8, wherein the input IN1 represents a percentage P: P(IN1)ϵ[0% . . . 100%], and the electronic selector is configured such that the recovery mode RM is selected as the active mode AM, when the percentage P(IN1) in relation to a value range [Min(T.sub.−(RPM.sub.E)), . . . , MAX(T.sub.+)] represents a negative torque T(IN1,RPM.sub.E), for which T.sub.−=T(IN1,RPM.sub.E)<0 and/or T(IN1,RPM.sub.E)<T−*, where T−*<0 indicates a limit for the negative torque T.sub.−, and where: P(IN1)=0% represents Min(T.sub.−(RPM.sub.E)) and P(IN1)=100% represents MAX(T.sub.+).

10. The aircraft according to claim 8, wherein the drive system comprises a torque sensor to detect the torque T acting on the electric motor E.

11. The aircraft according to claim 10, wherein the electronic controller is designed and set up to control a negative torque T=T.sub.− acting on the electric motor E according to at least one from the following list: an energy content of a battery connected to the electric motor E, a charging current to a battery connected to the electric motor E, a predefined minimum and/or maximum of the charging current, a temperature of the electric motor E and/or a battery, a predefined minimum and/or maximum of the temperature, a state of the electric motor E and/or the battery, a predefined minimum and/or maximum of the state, a current and/or a predefined speed of the aircraft, a predefined minimum and/or maximum of the speed, a current and/or predefined sink rate of the aircraft, a predefined minimum and/or maximum of the sink rate, from the input IN1, a rotational speed of the propeller P and/or of the electric motor E, a predefined minimum and/or maximum of the rotational speed, a currently generated electrical recovery energy E.sub.recup, a predefined minimum and/or maximum of the currently generated electrical recovery energy E.sub.recup, a current torque T transmitted from the propeller P to the electric motor E, a predefined minimum and/or maximum of the current torque T, a flight altitude and outside temperature, and an angle of attack of the propeller blades.

12. The aircraft according to claim 11, wherein the electronic controller is configured to control the torque T acting on the electric motor E by adjusting the electrical energy flow to/from the electric motor E and/or by adjusting the angle of attack of the propeller blades of the propeller P.

13. The aircraft according to claim 8, wherein the drive system comprises a sink for the electrical recovery energy E.sub.recup and/or a storage for the electrical recovery energy E.sub.recup, wherein the sink and/or the storage are connected to an energy management system, and wherein the energy management system is configured to control usage of the electrical recovery energy E.sub.recup with respect to the sink and/or the storage.

14. The aircraft according to claim 8, wherein the drive system comprises a display unit, the display unit configured to display one or more of the following information: information about the negative torque T.sub.− with which the electric motor E is driven, a parameter that depends on the negative T.sub.−, information about a positive torque T.sub.+ with which the propeller P is driven by the electric motor E, a parameter that depends on the positive torque T.sub.+, information about a current mode AM, and a currently generated electrical recovery energy E.sub.recup or a quantity derived from the currently generated recovery energy E.sub.recup.

15. A method of operating a drive system for an aircraft, the drive system comprising: a propeller P having propeller blades; an electric motor E; a transmission system to mechanically transmit a positive torque T.sub.+ from the electric motor E to drive the propeller P and to transmit a negative torque T from the propeller P in a windmill braking state to drive the electric motor E; a first input interface to input an input IN1 that defines power to be output by the electric motor E to drive the propeller P; an electronic controller to control a torque T acting on the electric motor E, where Tϵ{T.sub.−, 0, T.sub.+} and T.sub.−≤0 and T.sub.+≥0; a speed sensor to detect a rotational speed RPM.sub.E of the electric motor E; an electronic selector to select an active mode AM from a propulsion mode PM and a recovery mode RM, where AMϵ{PM, RM}, wherein in the recovery mode RM the electric motor E generates electrical recovery energy E.sub.recup from the negative torque T.sub.− transmitted by the transmission system from the propeller P; and an energy management system to control energy flow in an electrical system of the aircraft, the system comprising the electric motor E, according to the active mode AM; wherein the method comprises selecting the active mode AM by the electronic selector automatically according to the input IN1, the rotational speed RPM.sub.E of the electric motor E, and a predefined envelope, wherein the predetermined envelope indicates a maximum positive torque Max(T.sub.+) and a minimum negative torque Min(T.sub.−(RPM.sub.E)) that depends on the rotational speed RPM.sub.E of the electric motor E, or respective values that depend on same, wherein, for the torque T acting on the electric motor E, T=T(IN1,RPM.sub.E)ϵ[Min(T.sub.−(RPM.sub.E)), . . . , Max(T.sub.+)].

16. The method according to claim 15, wherein the input IN1 represents a percentage P: P(IN1)ϵ[0% . . . 100%], wherein the method comprises selecting the recovery mode RM by the electronic selector as the active mode AM, when the percentage P(IN1) in relation to a value range [Min(T.sub.−(RPM.sub.E)), . . . , MAX(T.sub.+)] represents a negative torque T(IN1,RPM.sub.E), for which T.sub.−=T(IN1,RPM.sub.E)<0 and/or T(IN1,RPM.sub.E)<T−*, where T−*<0 indicates a limit for the negative torque T.sub.−, and where: P(IN1)=0% represents Min(T.sub.−(RPM.sub.E)) and P(IN1)=100% represents MAX(T.sub.+).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, features and details result from the following description, in which—if necessary with reference to the drawings—at least one example embodiment is described in detail. Identical, similar, and/or functionally identical parts are provided with the same reference numerals.

(2) In the drawings:

(3) FIG. 1 shows a schematic representation of a drive system according to the invention; and

(4) FIG. 2 shows a representation to explain the operation of the selection unit.

DETAILED DESCRIPTION

(5) FIG. 1 shows a schematic representation of a drive system according to the invention for an aircraft. The drive system has: a propeller P 101 with two propeller blades, an electric motor E 102, a transmission system 103 to mechanically transmit a positive torque T.sub.+ from the electric motor E 102 to drive the propeller P 101 and to transmit a negative torque T from the propeller P 101 in a windmill braking state to drive the electric motor E 102.

(6) The drive system furthermore has a first input interface 104, which includes a selector lever to input an input IN1, and a first unit 105 to control a torque T acting on the electric motor E 102, where: Tϵ{T.sub.−, 0, T.sub.+} and T.sub.−≥0 and T.sub.+≥0. In the present case, the first unit 105 controls the angle of attack of the propeller blades and, via the energy management system, an energy flow from or to the electric motor E 102.

(7) The drive system further includes a second unit 106 to detect a rotational speed RPM.sub.E of the electric motor E 102; a selection unit 107 to select an active mode AM from a propulsion mode PM and a recovery mode RM, where AMϵ{PM, RM}, wherein the electric motor E (102) generates electrical recovery energy E.sub.recup in the recovery mode RM; and an energy management system 108 to control an energy flow in an electrical system 109 of the aircraft, the system including the electric motor E 102, according to the active mode AM; In addition to the electric motor E 102, the electrical system 109 includes a sink 112 to electrically recover energy E.sub.recup, in the present case an electric cabin heater, and a storage 113 to electrically recover energy E.sub.recup, in the present case an electrical battery.

(8) The selection unit 107 is configured and designed in such a way that the active mode AM is selected according to an input IN1 in the first input interface 104, according to the rotational speed RPM.sub.E of the electric motor E 102 and according to a predefined envelope, wherein the envelope indicates a maximum positive torque Max(T.sub.+) and a minimum negative torque Min(T.sub.−(RPM.sub.E)) that depends on a rotational speed RPM.sub.E of the electric motor E 102, or respective values that depend on same, wherein, for the torque T acting on the electric motor E 102, T=T(RPM.sub.E)ϵ[Min(T.sub.−(RPM.sub.E)), . . . , Max(T.sub.+)].

(9) In the present case, the input IN1 represents a percentage P: P=P(IN1)ϵ[0% . . . 100%]. Furthermore, the selection unit 107 is configured and designed in such a way that the recovery mode RM is selected as the active mode AM, when the percentage P(IN1) in relation to the value range [Min(T.sub.−(RPM.sub.E)), . . . , MAX(T.sub.+)] represents a negative torque T(IN1,RPM.sub.E), for which T.sub.−=T(IN1,RPM.sub.E)<0 and/or T(IN1,RPM.sub.E)<T−*, where T−*<0 indicates a limit for a negative torque T.sub.−, and where: P(IN1)=0% represents Min(T.sub.−(RPM.sub.E)) and P(IN1)=100% represents MAX(T.sub.+).

(10) The arrows indicated in FIG. 1 between the specified units indicate a flow of information and/or an interaction between the units.

(11) FIG. 2 shows a representation to explain the mode of operation of the selection unit 107 described in FIG. 1. A coordinate system is shown in which the rotational speed RPM.sub.E of the electric motor E 102 is plotted along the horizontal axis running to the right, wherein the rotational speed RPM.sub.E in the coordinate origin is zero and increasing to the right. The torque T acting on the electric motor E 102 is plotted along the vertical axis. A positive torque T=T.sub.+>0 is plotted above the horizontal axis, and a negative torque T=T.sub.−<0 is plotted below the horizontal axis. The maximum values MAX(T.sub.+) or minimum values Min(T.sub.−(RPM.sub.E)) characterizing the envelope are entered in the coordinate system. It can be clearly seen that MAX(T.sub.+) defines a constant torque, i.e., is independent of the rotational speed RPM.sub.E of the electric motor E 102. It can also be clearly seen that Min(T.sub.−(RPM.sub.E)) depends on the rotational speed RPM.sub.E. The envelope limits on the one hand a positive torque T.sub.+ transmitted from the electric motor E 102 to the propeller P 101, and on the other hand a negative torque T.sub.− transmitted from the propeller P 101 to the electric motor E 102. Min(T.sub.−(RPM.sub.E)) thus also defines a maximum absorbable torque for the recovery of electrical recovery energy E.sub.recup.

(12) The three vertical bars shown indicate value ranges [Min(T.sub.−(RPM.sub.E)), . . . , MAX(T.sub.+)] for three different rotational speeds RPM.sub.E, from which torques acting on the electric motor E 102 may be generated. If an input IN1 is made by a pilot at the first input interface 104, which corresponds to a percentage P=P(IN1)=0%, the maximum torque that can be absorbed for the recovery of electrical recovery energy E is obtained by the curve for Min(T.sub.−(RPM.sub.E)). If an input IN1 is made by a pilot at the first input interface 104, which corresponds to a percentage P=P(IN1)=100%, the maximum torque transmitted from the electric motor E 102 to the propeller is limited by the curve MAX(T.sub.+). If an input IN1 is now made by a pilot on the first input interface 104, which corresponds to a percentage P=P(IN1)=40%, this percentage represents 40% in relation to the value-dependent range of values [Min(T.sub.−(RPM.sub.E)), . . . , MAX(T.sub.+)] in case #1 a torque T=T.sub.+=T(IN1, RPM.sub.E)>0 of almost 40% of the allowed maximum positive torque MAX(T.sub.+), in case #2 a torque T=T.sub.+=T(IN1, RPM.sub.E)>0 of approx. 10% of the allowed maximum positive torque MAX(T.sub.+) and in case #3 a torque T=T.sub.−=T(IN1, RPM E)<0. In case #3, the pilot has set the lever of the first input interface 104 to 40% (e.g., power), but for example by initiating a strong descent and the torque input caused by the incoming air on the propeller P 101, the propeller P is not driven by the electric motor E 102 in this state 101, but the other way around, the propeller P 101 drives the electric motor E 102.

(13) In the present case, the selection unit 107 is designed and set up in such a way that the recovery mode RM is selected as the active mode AM when the percentage P(IN1) related to the value range [Min(T.sub.−(RPM.sub.E)), . . . , MAX(T.sub.+)] represents a negative torque T(IN1,RPM.sub.E), for which T−=T(IN1, RPM.sub.E)<0.

(14) In the present case, the selection of the active mode AM is carried out automatically.

(15) Although the invention has been illustrated and explained in greater detail using preferred example embodiments, the invention is not limited by the disclosed examples and other variations may be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that there is a variety of possible variations. It is also clear that embodiments cited by way of example actually only constitute examples that are not to be interpreted in any way as a limitation of the scope, of the potential applications, or of the configuration of the invention. Instead, the preceding description and the description of the figures enable the person skilled in the art to specifically implement the example embodiments, the person skilled in the art having knowledge of the disclosed inventive concept being able to make numerous changes, for example, with respect to the function or the arrangement of individual elements cited in an example embodiment, without departing from the scope of protection, which is defined by the claims and their legal equivalents, such as a further explanation in the description.

LIST OF REFERENCE NUMERALS

(16) 101 propeller P 102 electric motor E 103 transmission system 104 first input interface 105 first unit 106 second unit 107 selection unit 108 energy management system 109 electrical system 110 third unit 111 display unit 112 sink for electrical recovery energy E.sub.recup 113 storage for electrical recovery energy E.sub.recup