ENERGY RECOVERY SYSTEM AND METHOD FOR AN AIRCRAFT

Abstract

An energy recovery system and method for an aircraft having propellers. Specifically, the system and a method recover energy during the descent phase by setting the aircraft engines in propulsive mode or in windmill mode as needed. In windmill mode, the wind drives the propellers to generate electrical energy which may be stored. A pitch angle of the blade of the propellers may be changed.

Claims

1. An energy recovery system for an aircraft, the energy recovery system comprising: a plurality of pods configured to be attached to an aircraft wing, each pod comprising: a propeller, an electrical motor unit connected to the propeller through a shaft, a motor control unit configured to control the electrical motor unit, a main electrical supplying system connected with the motor control unit and configured to supply electrical energy to the electrical motor unit, a pitch control system configured to modify a pitch angle of the propeller, and a secondary electrical supplying system for electrical energy storage; and a power control management system in communication with the plurality of pods and configured to set each propeller through the motor control unit, during a descent phase, in a propulsive mode or in a windmill mode, depending on a load level of the respective secondary electrical supplying system in each pod and a required power to overcome air ram drag of the aircraft, wherein in the propulsive mode, the electrical motor unit is configured to actuate a rotation of the propeller, and wherein the windmill mode, the motor control unit is configured to operate the pitch control system so that the pitch angle of the propeller is modified for the propeller to rotate from wind, and the electrical motor unit is configured to generate electrical energy as result of the propeller rotation due to wind so that the generated electrical energy is stored within the secondary electrical supplying system.

2. The energy recovery system according to claim 1, wherein the main electrical supplying system is a fuel cell system.

3. The energy recovery system according to claim 1, wherein the secondary electrical supplying system is an electrical buffer.

4. The energy recovery system according to claim 1, further comprising: a shared storage system, wherein the shared storage system is connected with the motor control unit of each pod and is configured to store at least part of the electrical energy generated on the windmill mode.

5. The energy recovery system according to claim 1, wherein at least one diode is arranged on the motor control unit or on the main electrical supplying system or in a connection between the motor control unit and the main electrical supplying system, said at least one diode being configured to prevent the electrical energy generated in windmill mode from reaching the main electrical supplying system.

6. An aircraft comprising: the energy recovery system according to claim 1.

7. A method for recovering energy during a descent phase of an aircraft, the aircraft comprising a plurality of pods and each pod comprising a propeller, an electrical motor unit and a secondary electrical supplying system, the method comprising: a) determining a minimum number of propellers needed to provide a required power to overcome air ram drag in a descent phase of the aircraft; b) setting the minimum number of propellers as determined in step a) in propulsive mode, wherein said minimum number of propellers are those with a highest load level of the respective secondary electrical supplying system; c) setting at least one of a remaining propellers in windmill mode by modifying a pitch angle of the remaining propeller for the remaining propeller to rotate based on wind; d) generating electrical energy by the electrical motor unit through a rotation of the at least one of the remaining propellers set in windmill mode; and e) recharging the respective secondary electrical supplying system with the electrical energy generated in step d).

8. The method according to claim 7, further comprising: partially extending flaps of the aircraft.

9. The method according to claim 7, wherein step b) comprises actuating a rotation of propellers in propulsive mode through the electrical motor unit of the respective pod.

10. The method according to claim 9, wherein the electrical motor unit is energy supplied by a main electrical supplying system of the respective pod.

11. The method according to claim 7, wherein the pitch angle of each propeller to be set in windmill mode in step c) is modified through a pitch control system of the respective pod.

12. The method according to claim 11, wherein the pitch control system is operated by a power control management system.

13. The method according to claim 12, wherein the motor control unit controls an operation of the electrical motor unit as an actuator for a rotation of the propeller in propulsive mode and as an electrical power generator in windmill mode.

14. The method according to claim 7, wherein steps a) to c) are controlled by a power control management system of the aircraft.

15. The method according to claim 7, further comprising: storing at least part of the electrical energy generated on the windmill mode in a shared storage system of the aircraft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0078] These and other characteristics and advantages of the invention will become clearly understood in view of the detailed description of the invention which becomes apparent from a preferred embodiment of the invention, given just as an example and not being limited thereto, with reference to the drawings.

[0079] FIG. 1 shows a schematic view of an energy recovery system according to an embodiment of the present invention.

[0080] FIG. 2 shows a schematic view of an aircraft comprising an energy recovery system according to an embodiment of the present invention.

[0081] FIG. 3 shows a schematic view of an aircraft comprising an energy recovery system according to an embodiment of the present invention.

[0082] FIG. 4 shows a schematic view of an aircraft comprising an energy recovery system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0083] The present invention provides an energy recovery system for an aircraft (10). The energy recovery system comprises a plurality of pods (1, 1a, 1b, 1c, 1d) attached to the wings (11) of the aircraft (10), for example attached to the intrados of the wings (11) of the aircraft (10) as shown in any of FIGS. 2 to 4. Specifically, these FIGS. 2 to 4 show a turboprop propelled aircraft (10) comprising four pods (1, 1a, 1b, 1c, 1d) distributed between the two wings (11).

[0084] FIG. 1 shows a schematic view of one of these pods (1, 1a, 1b, 1c, 1d). The pod (1, 1a, 1b, 1c, 1d) has a propeller (2) comprising a rotating power-driven hub or rotor (2.1) to which are attached several radial blades (2.2) such that the whole assembly rotates about a longitudinal axis.

[0085] The pod (1, 1a, 1b, 1c, 1d) further comprises an electrical motor unit (3) connected to the propeller (2) through a shaft (4) along the longitudinal axis already mentioned above. Specifically, the propeller (2) is attached to the electrical motor unit (3) either directly or through a gearbox. As can be seen in FIG. 1, the propeller (2) is arranged outside the pod (1, 1a, 1b, 1c, 1d) whilst the electrical motor unit (3) is arranged within the pod (1, 1a, 1b, 1c, 1d).

[0086] The pod (1, 1a, 1b, 1c, 1d) further comprises inside a motor control unit (5) for controlling the operation of the electrical motor unit (3), among other components.

[0087] The pod (1, 1a, 1b, 1c, 1d) also comprises a main electrical supplying system (6) connected to the motor control unit (5) and configured to supply the electrical energy the electrical motor unit (3) needs for its operation. In the embodiment shown in FIG. 1, the main electrical supplying system (6) is a fuel cell system.

[0088] The energy recovery system also provides a pitch control system (not shown) within the pod (1, 1a, 1b, 1c, 1d). The pitch control system is connected with the propeller (2) and is in charge of modifying the pitch angle of the propeller (2). The pitch control system is operated if the pitch angle needs to be modified.

[0089] In addition, there is a secondary electrical supplying system (7) arranged within the pod (1, 1a, 1b, 1c, 1d). This secondary electrical supplying system (7) is configured to store electrical energy generated by the electrical motor unit (3) as a result of the propeller (2) rotation due to the effect of wind on the propeller (2). In the embodiment shown in FIG. 1, the secondary electrical supplying system (7) is an electrical buffer.

[0090] The propellers (2) of the energy recovery system are configured with at least two operating modes which are a propulsive mode and a windmill mode. For determining the operating mode for each propeller (2), the energy recovery system comprises a power control management system (8) as shown in FIGS. 2 to 4. The power control management system (8) is in communication with all the pods (1, 1a, 1b, 1c, 1d) of the aircraft (10) for setting each propeller (2) through the motor control unit (5), during descent phase of the aircraft (10), in any of the operating modes (propulsive mode or windmill mode). The setting of each propeller (2) to one mode or the other is based on the load level of the respective secondary electrical supplying system (7) in each pod (1, 1a, 1b, 1c, 1d) and the power to be required to overcome air ram drag of the aircraft during the descent phase.

[0091] When one pod (1, 1a, 1b, 1c, 1d) is set in propulsive mode, the electrical motor unit (3) is switched to electrical motor mode for actuating the rotation of the respective propeller (2).

[0092] When one pod (1, 1a, 1b, c, 1d) is set in windmill mode, the pitch control system is operated by the power control management system (8) to modify the pitch angle of the propeller (2) for the propeller (2) to rotate under the effect of the wind. In addition, for the windmill mode the electrical motor unit (3) is set as a generator and generates electrical energy due to the propeller (2) rotations because of the effect of the wind. Also, the electrical energy generated by the electrical motor unit (3) is stored within the secondary electrical supplying system (7). The motor control unit (5) changes the pitch angle of the propeller (2) from a predefined pitch angle for the predefined descent phase of the aircraft (10).

[0093] FIG. 1 further shows the operation in the pod (1, 1a, 1b, 1c, 1d) for both operating modes. The propulsive mode is represented with dashes as the main electrical supplying system (6) powering the electrical motor unit (3) for the rotation of the propeller (2). By contrast, the windmill mode is represented in dots as the propeller (2) charging up the secondary electrical supplying system (7).

[0094] In an embodiment, the energy recovery system further comprises a shared storage system (9) as shown in FIG. 4. This shared storage system (9) is connected with the motor control unit (5) of each pod (1, 1a, 1b, 1c, 1d) and is used to store part of the electrical energy generated by the electrical motor unit (3) corresponding to the pods (1, 1a, 1b, 1c, 1d) set in windmill mode.

[0095] In an embodiment, such as the one shown in FIG. 1, the motor control unit (5) of the energy recovery system comprises two diodes. In another embodiment, the diodes are located on the main electrical supplying system (6) or in the connection between the motor control unit (5) and the main electrical supplying system (6).

[0096] The present invention further provides a method for recovering energy during descent phase of an aircraft (10) comprising a plurality of pods (1, 1a, 1b, lc, 1d), wherein each pod (1, 1a, 1b, 1c, 1d) comprises a propeller (2), an electrical motor unit (3) and a secondary electrical supplying system (7). This method is described below according to the different scenarios shown by FIGS. 2 to 4.

[0097] The method firstly determines for the descent phase of the aircraft (10) the required power for overcoming air ram drag. Alternatively, the required power for overcoming the air ram drag is provided as a predefined data.

[0098] In an embodiment, the method further comprises partially extending the flaps of the aircraft (10).

[0099] The method comprises in step a) determining by the power control management system (8) the minimum number of propellers (2) needed to provide the required power to overcome the air ram drag in the descent phase.

[0100] For selecting which propellers (2) are going to be set for providing the required power to overcome the air ram drag, the power control management system (8) checks the load level of each of the secondary electrical supplying systems (7) and selects those whose load level is higher, as many as the minimum number of propellers (2) determined in step a). The selected propellers (2) are set in propulsive mode according to step b). In addition, step b) comprises actuating the rotation of the selected propellers to be set in propulsive mode by the electrical motor unit (3). Specifically, it is the main electrical supplying system (6) which is in charge of supplying power to the operation of the electrical motor unit (3).

[0101] For example, in the case that the power control management system (8) determines that two propellers (2) are necessary for overcoming the air ram drag in the descent phase, FIGS. 2 and 4 show different strategies.

[0102] In the embodiments of FIGS. 2 and 4, the secondary electrical supplying system (7) of the first pod (1a) has 25% of load, the secondary electrical supplying system (7) of the second pod (1b) has 98% of load, the secondary electrical supplying system (7) of the third pod (1c) has 89% of load, and the secondary electrical supplying system (7) of the forth pod (1d) has 36% of load. In this embodiment, those secondary electrical supplying systems (7) with the highest load levels, that is, the secondary electrical supplying systems (7) of the second pod (1b) and third pod (1c), are those for which the corresponding propellers (2) are to be set in the propulsive mode.

[0103] In another example, in case that the power control management system (8) determines that it is necessary three propellers (2) for overcoming the air ram drag in the descent phase, FIG. 3 shows a strategy accordingly.

[0104] In the embodiment of FIG. 3, the secondary electrical supplying system (7) of the first pod (1a) has 95% of load, the secondary electrical supplying system (7) of the second pod (1b) has 87% of load, the secondary electrical supplying system (7) of the third pod (1c) has 62% of load, and the secondary electrical supplying system (7) of the forth pod (1d) has 95% of load. In this embodiment, those secondary electrical supplying systems (7) with the highest load levels, that is, the secondary electrical supplying systems (7) of the first pod (1a), second pod (1b) and forth pod (1d), are those for which the corresponding propellers (2) are to be set in the propulsive mode.

[0105] The method further comprises in step c) setting at least one propeller (2) of the remaining propellers (2) in windmill mode. The windmill mode leads the pitch control system to modify the pitch angle of at least one propeller (2) of the remaining propellers (2) for the propeller (2) to rotate under the effect of the wind on such propeller (2). It is the power control management system (8) which actuates the pitch control system for setting in windmill mode the corresponding propeller (2).

[0106] That is, once the minimum number of propellers (2) needed in propulsive mode are selected, then the method comprises in step c) setting at least one of the remaining propellers in windmill mode. One of the remaining propellers will be linked to a secondary electrical supplying system whose load level is lower than that of the propellers set in propulsion mode. In an embodiment, the propeller whose respective secondary electrical supplying system has the lowest load level is chosen from among all the remaining propellers to be set in windmill mode. In an embodiment, a plurality of the remaining propellers (2) are set in windmill mode. In an embodiment, all the remaining propellers (2) are set in windmill mode.

[0107] According to FIGS. 2 and 4, the remaining propellers (2) whose corresponding secondary electrical supplying systems (7) have a load level of 25% and 36% are set in windmill mode. That is, the first pod (1a) and the fourth pod (1d) are set in windmill mode in both embodiments of FIGS. 2 and 4. According to FIG. 3, the remaining propeller (2) whose corresponding secondary electrical supplying system (7) has a load level of 65% is set in windmill mode. That is, the third pod (1c) is set in windmill mode.

[0108] Depending on which operating mode is determined for each propeller (2), its respective electrical motor unit (3) is configured as an actuator for the rotation of the propeller (2) for the propulsive mode or as an electrical power generator for the windmill mode.

[0109] Once one or more of the remaining propellers (2) are set in windmill mode, the corresponding electrical motor units (3) start according to step d) to generate electrical energy through the rotation of the propellers (2) set in windmill mode, specifically those with a lower load level as specified in particular for examples in FIGS. 2 to 4.

[0110] Furthermore, such electrical energy that is generated by the electrical motor units (3) is then transferred to the corresponding secondary electrical supplying systems (7), specifically to those which have lowest load levels for recharging the secondary electrical supplying system (7).

[0111] To set in a windmill mode leads to modifying the pitch angle of the propeller for the propeller to rotate under the effect of the wind. This means that the propeller set in windmill mode starts rotating under the effect of the wind and this rotation is converted into electrical energy by an electrical motor unit connected to the selected propeller. Therefore, in the windmill mode the pitch angle of the propeller is changed from a predefined pitch angle for the predefined descent phase of the aircraft. In this case, the electrical motor unit is switched to generator mode for extracting the energy from the propeller rotation.

[0112] By last, the method comprises in step e) storing the electrical energy generated in step d) in the secondary electrical supplying system corresponding to the propeller set in windmill mode. Thus, the secondary electrical supplying system with low load level is recharged during the descent phase of the aircraft through the at least one propeller set in windmill mode.

[0113] Steps a) to c) are controlled by the power control management system (8) of the energy recovery system provided in the aircraft (10).

[0114] In an embodiment, the method further comprises storing part of the electrical energy generated by the electrical motor unit (3) in windmill mode in the shared storage system (9) as shown in FIG. 4. In this example, the load level of the secondary electrical supplying systems (7) is the same as in the example of FIG. 3.

[0115] In an embodiment, the power control management system (8) changes the configuration of a propeller (2) from windmill mode to propulsive mode or vice versa as needed during descent phase of the aircraft (10). For example, if the power control management system (8) detects that a propeller (2) set in windmill mode for which respective secondary electrical supplying system (7) has been fully recharged, this propeller (2) is switched from windmill mode to the propulsive mode. In addition, among the remaining propellers (2) in the propulsive mode, the one for which respective secondary electrical supplying system (7) is with the lowest load level, this propeller (2) is switched from propulsive mode to windmill mode.

[0116] The systems and devices described herein may include a controller or a computing device comprising a processing unit and a memory which has stored therein computer-executable instructions for implementing the processes described herein. The processing unit may comprise any suitable devices configured to cause a series of steps to be performed so as to implement the method such that instructions, when executed by the computing device or other programmable apparatus, may cause the functions/acts/steps specified in the methods described herein to be executed. The processing unit may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

[0117] The memory may be any suitable known or other machine-readable storage medium. The memory may comprise non-transitory computer readable storage medium such as, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory may include a suitable combination of any type of computer memory that is located either internally or externally to the device such as, for example, random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. The memory may comprise any storage means (e.g., devices) suitable for retrievably storing the computer-executable instructions executable by processing unit.

[0118] The methods and systems described herein may be implemented in a high-level procedural or object-oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of the controller or computing device. Alternatively, the methods and systems described herein may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems described herein may be stored on the storage media or the device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein.

[0119] Computer-executable instructions may be in many forms, including modules, executed by one or more computers or other devices. Generally, modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically, the functionality of the modules may be combined or distributed as desired in various embodiments.

[0120] It will be appreciated that the systems and devices and components thereof may utilize communication through any of various network protocols such as TCP/IP, Ethernet, FTP, HTTP and the like, and/or through various wireless communication technologies such as GSM, CDMA, Wi-Fi, and WiMAX, is and the various computing devices described herein may be configured to communicate using any of these network protocols or technologies.

[0121] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.