Direct drive electric geared turbofan

Abstract

To provide turbofan engines configured to convert mechanical rotational energy from turbine-driven spool shafts into mechanical rotational energy in a fan via electromagnet forces.SOLUTION: The present disclosure provides a direct drive electrically-geared turbofan comprising: a first magnetic gearbox assembly 210A connected to a fan 150; a second magnetic gearbox assembly 210B connected to a spool shaft 160A of a turbofan engine; and a speed controller configured to adjust a rotational speed of the fan by selectively coupling and decoupling the magnetic gearbox assembly. The magnetic gearbox assemblies include a permanent magnet array, while including a rotor winding separated from the permanent magnet array by an air gap 230. The speed controller is configured to selectively couple and decouple the magnetic gearbox assemblies mutually by controlling a switch in a winding circuit with the rotor winding.SELECTED DRAWING: Figure 2C

Description

[Technical Field]

[0001] Aspects of the present disclosure relate generally to turbofan engines, and more particularly to turbofan engines configured to convert rotational mechanical energy from a turbine drive spool shaft into rotational mechanical energy in a fan via electromagnetic forces. [Background technology]

[0002] In a turbofan engine, the high-pressure exhaust from burning fuel in the combustion chambers spins various turbines. As these turbines rotate, they impart rotation to a spool shaft. The spool shaft is then connected to various compressors that supply air to the combustion chambers, and to fans that propel the air through bypass chambers around the turbines. The air propelled by the fans provides part of the turbofan engine's motive power (often a significant part of "high bypass" turbofan engines).

[0003] During operation of a conventional turbofan engine, mechanical gearing (e.g., planetary gears) allows the fan to rotate at a different rotational speed than the spool shaft that provides the rotational force to the fan. Mechanical gearing is often heavy and bulky, prone to mechanical stresses (e.g., wear, material fatigue, lubricant leakage, etc.), and requires frequent inspection and maintenance to function properly. Furthermore, mechanical gearing can introduce noise and vibration into the turbofan engine due to the physical contact between parts, in addition to the mechanical stresses between the components of the mechanical gearing itself. Summary of the Invention

[0004] The present disclosure provides, in one aspect, a system including: a first magnetic gearbox assembly connected to a fan of a turbofan engine; a second magnetic gearbox assembly connected to a spool shaft of the turbofan engine; and a speed controller configured to adjust a rotational speed of the fan based on a rotational speed of the spool shaft by selectively coupling and decoupling the first magnetic gearbox assembly with the second magnetic gearbox assembly.

[0005] In one aspect, in combination with any example system above or below, the first magnetic gearbox assembly includes: a first magnetic gearbox assembly; a second magnetic gearbox assembly including a rotor winding separated from the permanent magnet array by an air gap; and a speed controller configured to selectively couple and decouple the first magnetic gearbox assembly with the second magnetic gearbox assembly by opening and closing a switch in a winding circuit having the rotor winding.

[0006] In one aspect, in combination with any exemplary system above or below, the second magnetic gearbox assembly includes a permanent magnet array; the first magnetic gearbox assembly includes a rotor winding separated from the permanent magnet array by an air gap; and the speed controller is configured to selectively couple and decouple the first magnetic gearbox assembly with the second magnetic gearbox assembly by opening and closing switches in a winding circuit having the rotor winding.

[0007] In one aspect, in combination with any exemplary system described above or below, a first magnetic gearbox assembly is coaxially disposed within a cavity defined by a second magnetic gearbox assembly.

[0008] In one aspect, in combination with any of the exemplary systems described above or below, a second magnetic gearbox assembly is coaxially disposed within a cavity defined by the first magnetic gearbox assembly.

[0009] In one aspect, in combination with any of the exemplary systems described above or below, the first magnetic gearbox assembly and the second magnetic gearbox assembly are electromagnetically coupled via a coaxial magnetic field.

[0010] In one aspect, in combination with any exemplary system described above or below, the speed controller is configured to decouple the first magnetic gearbox assembly from the second magnetic gearbox assembly by opening at least a switch with a switch driver powered by a current generated by the first magnetic gearbox assembly rotating relative to the second magnetic gearbox assembly.

[0011] In one aspect, in combination with any of the exemplary systems described above or below, the speed controller is configured to adjust the rotational speed of the fan based on a difference between a reference speed of the fan and a measured speed of the fan.

[0012] In one aspect, in combination with any exemplary system described above or below, the speed controller further includes a speed sensor, the speed sensor including at least one of: a Hall effect sensor; an inductive sensor; or an optical isolator sensor.

[0013] In one aspect, in combination with any example system described above or below, the system further includes an engine thrust controller configured to transmit the reference speed to the speed controller via contactless communication.

[0014] In one aspect, the present disclosure provides a turbofan engine including: a fan; a turbine enclosure including an air intake at an upstream end; a compression section downstream of the air intake; a combustion section downstream of the compression section; a turbine section downstream of the combustion section; and an exhaust at a downstream end; a first spool shaft coupled to a first compressor in the compression section and a first turbine in the turbine section; an electric gearbox upstream of the turbine enclosure, the electric gearbox configured to transfer rotational energy from the first spool shaft rotating at a second rotational speed to a fan rotating at a first rotational speed through an air gap between a first magnetic gearbox assembly and a second magnetic gearbox assembly; and a speed controller coupled to the electric gearbox and configured to selectively couple and decouple the first magnetic gearbox assembly with the second magnetic gearbox assembly over the air gap to regulate the first rotational speed to a variable fan reference speed while maintaining the second rotational speed at a constant speed.

[0015] In one aspect, in combination with any exemplary turbofan engine described above or below, the first magnetic gearbox assembly includes a permanent magnet array, the second magnetic gearbox assembly includes a winding circuit defining a rotor winding; and the speed controller is configured to reduce a duty cycle of a switch in the winding circuit to reduce the first rotational speed relative to the second rotational speed.

[0016] In one aspect, in combination with any exemplary turbofan engine described above or below, the first magnetic gearbox assembly includes a winding circuit defining a rotor winding, the second magnetic gearbox assembly includes a permanent magnet array; and the speed controller is configured to reduce a duty cycle of a switch in the winding circuit to reduce the first rotational speed relative to the second rotational speed.

[0017] In one aspect, in combination with any exemplary turbofan engine described above or below, the air gap is one of: coaxial with the first spool shaft defined by the first magnetic gearbox assembly within the second cavity defined by the second magnetic gearbox assembly; and perpendicular to the axis of rotation of the first spool shaft defined by positioning the first magnetic gearbox assembly parallel to the second magnetic gearbox assembly.

[0018] The present disclosure provides, in one aspect, a method that includes: rotating a spool shaft of a turbofan engine at a first rotational speed; transferring rotational energy from the spool shaft to a fan of the turbofan engine via an electrical gearbox; transferring rotational energy from the spool shaft to a fan of the turbofan engine via an electrical gearbox; and rotating the fan at a second rotational speed based on a duty cycle.

[0019] In one aspect, in combination with any example method above or below, an electric gearbox includes: a first magnetic gear assembly including a winding circuit and a switch, coupled to the spool shaft; and a second magnetic gearbox assembly including a permanent magnet array, coupled to a fan, and separated from the first magnetic gearbox assembly by an air gap.

[0020] In one aspect, in combination with any example method above or below, an electric gearbox includes: a first magnetic gearbox assembly including a winding circuit and a switch and coupled to the fan; and a second magnetic gearbox assembly including a permanent magnet array and coupled to the spool shaft, separated from the first magnetic gearbox assembly by an air gap.

[0021] In one aspect, in combination with any example method above or below, the method further includes: measuring a second rotational speed; and in response to the second rotational speed not matching within a threshold of the fan reference speed, adjusting a duty cycle of the switch while continuing to rotate the spool shaft at the first rotational speed.

[0022] The present disclosure provides, in one aspect, a method including: attaching a first magnetic gearbox assembly to a first spool shaft of a turbofan engine, the first magnetic gearbox assembly including a first winding circuit defining a rotor winding having a selectively configurable switch and a permanent magnet array; attaching a second magnetic gearbox assembly to a fan of the turbofan engine, the second magnetic gearbox assembly including a winding circuit and permanent magnet array different from the first magnetic gearbox assembly, the first magnetic gearbox assembly and the second magnetic gearbox assembly defining an air gap therebetween; attaching a speed sensor 520 to the turbofan engine to monitor a rotational speed of the fan; and coupling a speed controller to the speed sensor and the winding circuit, the speed controller configured to adjust a duty cycle of the selectively configurable switch based on a difference between the rotational speed of the fan and a reference speed of the fan.

[0023] In one aspect, in combination with any exemplary method above or below, mounting the first magnetic gearbox assembly and mounting the second magnetic gearbox assembly define an air gap by one of: disposing the first magnetic gearbox assembly in a first cavity defined by the second magnetic gearbox assembly, wherein the air gap is coaxial with the first spool shaft; and disposing the first magnetic gearbox assembly in parallel with the second magnetic gearbox assembly, wherein the air gap is perpendicular to the axis of rotation of the first spool shaft.

[0024] The present disclosure provides, in one aspect, a processing system, the processing system including: a memory including computer-executable instructions; and a processor configured to execute the computer-executable instructions to cause the processing system to perform any of the methods described above.

[0025] In one aspect, the present disclosure provides a non-transitory computer-readable medium that includes computer-executable instructions that, when executed by a processor of a processing system, cause the processing system to perform any of the methods described above.

[0026] The present disclosure provides in one aspect a computer program product, the computer program product embodied on a computer-readable storage medium comprising code for performing any of the methods described above.

[0027] So that the features described above can be understood in detail, a more particular description can be had by reference to illustrative embodiments, some of which are illustrated in the accompanying drawings. [Brief explanation of the drawings]

[0028] [Figure 1A] FIG. 1 illustrates a cross-sectional view of a turbofan engine including an electric gearbox according to aspects of the present disclosure. [Figure 1B] FIG. 1 illustrates a cross-sectional view of a turbofan engine including an electric gearbox according to aspects of the present disclosure. [Figure 1C] FIG. 1 illustrates a cross-sectional view of a turbofan engine including an electric gearbox according to aspects of the present disclosure. [Figure 2A] 1A-1D illustrate cross sections of various configurations of an electric gearbox according to aspects of the present disclosure. [Figure 2B] 1A-1D illustrate cross sections of various configurations of an electric gearbox according to aspects of the present disclosure. [Figure 2C] 1A-1D illustrate cross sections of various configurations of an electric gearbox according to aspects of the present disclosure. [Figure 3A-3C] 1 illustrates a winding circuit within a permanent magnet array for use in an electric gearbox, according to an aspect of the present disclosure. [Figures 4A-4C] 1 illustrates an external winding circuit of a permanent magnet array for use in an electric gearbox, according to an aspect of the present disclosure. [Figure 5A] 1 illustrates a speed controller for an electric gearbox according to an aspect of the present disclosure. [Figure 5B] 1 illustrates a speed controller for an electric gearbox according to an aspect of the present disclosure. [Figure 5C] 1 illustrates a speed controller for an electric gearbox according to an aspect of the present disclosure. [Figure 6] 1 is a flowchart of a method for controlling a turbofan engine having an electric gearbox in accordance with an aspect of the present disclosure. [Figure 7] 1 is a flowchart of a method for manufacturing a turbofan engine having an electric gearbox according to an aspect of the present disclosure. [Figure 8A] 1 illustrates the arrangement of components of a generator according to aspects of the present disclosure. [Figure 8B] 1 illustrates the arrangement of components of a generator according to aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present disclosure provides a controllable electrically geared turbofan engine that uses a mechanical gearing arrangement between the spool shaft and the fan in place of an electromagnetic coupling. The electromagnetic coupling allows for the transfer of rotational energy / torque without physical contact between the gear components, thereby reducing the weight and size of the turbofan engine assembly as well as reducing the maintenance requirements for the gearing compared to mechanical gearing.

[0030] A speed controller is provided that adjusts the effective "gear ratio" between the spool shaft and the fan, allowing for more continuous control of the fan's rotational speed (e.g., revolutions per minute (RPM)). In other words, the fan's rotational speed can be controlled independently of the spool shaft's rotational speed, thereby allowing the fan to be driven at variable speeds while the spool shaft is driven at a relatively constant speed optimized for various performance characteristics of the turbofan engine. Advantageously, the electromagnetic gearbox and speed controller of the present disclosure can provide greater fuel efficiency over a wider range of turbofan engine thrust and speeds than is provided by conventional statically geared turbofan engines.

[0031] Although the examples provided in this disclosure primarily refer to aircraft turbofans, the electrical gearing described in this disclosure can be used in combination with turbofan engines in a variety of other vehicles.

[0032] 1A-1C illustrate cross-sectional views of turbofan engines 100 (respectively, turbofan engine 100A and turbofan engine 100B) including an electrical gearbox 110 according to an embodiment of the present disclosure. Turbofan engine 100 includes a turbine enclosure 120 defining an air intake 121 at an upstream end, a compression section 122 downstream of air intake 121, a combustion section 123 downstream of compression section 122, a turbine section 124 downstream of combustion section 123, and an exhaust system 125 at a downstream end. In various embodiments, turbine enclosure 120 is contained within a nacelle 130 (also referred to as a housing), and a bypass flow chamber 131 is defined between an exterior surface of turbine enclosure 120 and an interior surface of nacelle 130. The fan 150 is positioned in the nacelle 130 upstream of the air intake 121 of the turbine enclosure 120 and rotates during operation to propel air inside the air intake 121 of the turbine enclosure 120 and through the bypass flow chamber 131, thereby providing an intake charge and thrust.

[0033] 1A shows a turbofan engine 100 including a first spool shaft 160A (generally, spool shaft or shaft 160, or collectively, shaft assembly) and a second spool shaft 160B. While FIG. 1B shows a turbofan engine including a first spool shaft 160A, a second spool shaft 160B, and a third spool shaft 160C, in various aspects, the turbofan engine 100 may include one, two, three, or more spool shafts 160.

[0034] In the embodiment shown, each shaft 160 extends coaxially with the other shafts 160 and rotates at different speeds during operation due to the discharge of high-pressure exhaust gas that rotates turbines 180A-B (generally turbines 180) in FIG. 1A or turbines 180A-C in FIG. 1B, which in turn drive associated compressors 170A-B (generally compressors 170) in FIG. 1A or compressors 170A-C in FIG. 1B at different speeds via connected spool shafts 160. For example, first spool shaft 160A rotates (due to force imparted by first turbine 180A) to drive the rotation of first compressor 170A at a first rotational speed, while second spool shaft 160B rotates (due to force imparted by second turbine 180B) to drive the rotation of second compressor 170B at a second rotational speed. Although not shown, various bearings or low friction surfaces may be positioned between shafts 160 to improve the rotational characteristics of shafts 160 (eg, to reduce friction).

[0035] The compressors 170 are disposed within the compression section 122 of the turbine enclosure 120 and may each include a number of fan blades arranged in one or more rows. The turbines 180 are disposed within the turbine section 124 of the turbine enclosure 120 and may each include a number of turbine blades arranged in one or more rows.

[0036] As shown, first spool shaft 160A is a low-pressure shaft relative to the high-pressure shaft of second spool shaft 160B. Accordingly, first compressor 170A is disposed upstream of second compressor 170B and rotates at a lower rotational speed than second compressor 170B during operation of turbofan engine 100. Additionally, first turbine 180A is disposed downstream of second turbine 180B and rotates at a lower rotational speed than second turbine 180B during operation of turbofan engine 100. Similarly, referring to FIG. 1B , second compressor 170B is disposed upstream of third compressor 170C and rotates at a lower rotational speed than third compressor 170C during operation of turbofan engine 100. Additionally, second turbine 180B is disposed downstream of third turbine 180C and rotates at a lower rotational speed than third turbine 180C during operation of turbofan engine 100.

[0037] Rotation of low pressure first spool shaft 160A is transferred to fan 150 via electrical gearbox 110. As fan 150 rotates, it forces air through bypass flow chamber 131 of turbofan engine 100 to provide motive power (e.g., thrust) for a vehicle using turbofan engine 100. Fan 150 includes a plurality of fan blades 151 extending from a central hub 152 and generally has a larger radius than the corresponding blades of compressor 170 (and turbine 180) within turbofan engine 100. Thus, if rotated at the same angular or rotational speed (e.g., revolutions per minute) as the compressor 170, the fan 150 would be subjected to higher speeds (and mechanical stresses) at the distal ends of the fan blades 151 than the blades of the compressor 170 and turbine 180. For example, the tips of the blades of the compressor 170 (and turbine 180) may move at subsonic speeds, but the tips of the fan 150 rotating with the subsonic compressor 170 (and turbine 180) may move at supersonic speeds due to the large radius of the fan 150, which can cause noise and vibration problems (in addition to mechanical stresses) as the tips of the fan blades 151 break the sound barrier.

[0038] 2A-2C, 3A-3C, and 4A-4C, couples the first spool shaft 160A to the hub 152 of the fan 150, allowing the first spool shaft 160A (and associated first compressor 170A) to rotate at one rotational speed and the fan 150 to rotate at an independent rotational speed. Independent rotational speeds can include cases where the fan 150 rotates faster, slower, or at the same speed as the first spool shaft 160A. In some embodiments, an operator can also vary the speeds of the fan 150 and the first spool shaft 160A relative to one another (e.g., to accelerate or slow down the fan 150).

[0039] Rather than physically interlocking gears, the electric gearbox 110 uses magnetically coupled components as a gear system to electromagnetically couple the first spool shaft 160A to the fan 150, so that the portions of the electric gearbox 110 physically connected to the first spool shaft 160A and the fan 150 do not physically contact one another. Instead, a controllable electromagnetic field selectively couples the first spool shaft 160A to the fan 150 through an air gap. An operator controls whether the winding circuits are open or closed, thus selectively coupling and decoupling components of the electric gearbox 110 to set an effective gear ratio based on the duty cycle of the winding circuits. In various embodiments, a control signal can be sent to the electric gearbox 110 to vary the duty cycle and the ratio between fan speed and shaft speed to control the fan speed.

[0040] Thus, the electric gearbox 110 is configured to transfer rotational energy from the spool shaft 160 to the fan 150. In some embodiments, the electric gearbox 110 is configured to maintain a static gear ratio or is controlled via shaft speed without further control signal input. Power to generate these electromagnetic fields can be provided by a power distribution bus 145 or other power transfer mechanism for the vehicle on which the turbofan engine 100 is located (e.g., via a transfer cable 140 or a wireless resonant power transmitter), as in FIGS. 1A and 1B, or via a generator 190 connected between the two spool shafts 160, as in FIG. 1C, which is discussed in more detail in connection with FIGS. 8A-8B. In some embodiments using a generator 190, the power distribution bus 145 and / or transfer cable 140 may be omitted.

[0041] This allows the electric gearbox 110 to selectively couple and decouple the fan 150 from the first spool shaft 160A, thereby allowing the spool shaft 160 to rotate at a constant speed and the fan 150 to rotate at different speeds (based on a constant or variable fan reference speed).

[0042] 1C , a generator 190 is disposed at the interface between the first spool shaft 160A and the second spool shaft 160B (and / or the interface between the second spool shaft 160B and the third spool shaft 160C) to extract electrical energy based on the different rotational speeds of the spool shafts 160. By attaching components of the generator 190 to two different spool shafts (e.g., 160A and 160B) or two different compressors (e.g., 170A and 170B) at their respective interfaces, the generator 190 can convert rotational energy into electrical energy via a series of induced magnetic fields based on the differential rotational speeds, without requiring physical contact between the generator components rotating at different speeds, which can then be transmitted to various systems inside and outside the turbofan engine 100. The generator 190 utilizes the different rotational speeds of the compressors 170 attached to the different shafts 160 to rotate the components relative to one another using the operating rotation of the turbofan engine 100 components. The structure of the generator 190 is described in more detail in connection with Figures 8A-8B.

[0043] 2A-2C illustrate cross sections of various configurations of electric gearbox 110 according to embodiments of the present disclosure. As will be appreciated, electric gearbox 110 may include a housing or other cover to protect internal components, such as mounting hardware for securing electric gearbox 110 to fan 150 and / or spool shaft 160, from debris, reduce air resistance, etc. Such mechanical features have been omitted from the figures to clarify the electromagnetic components and their operation.

[0044] In each configuration shown in Figures 2A-2C, a first magnetic gearbox assembly 210A (generally, magnetic gearbox assembly 210) is connected to the fan 150, and a second magnetic gearbox assembly 210B is connected to the first spool shaft 160A. As described in more detail with respect to Figures 3A-3C and 4A-4C, one of the magnetic gearbox assemblies 210 includes a permanent magnet array, and the other magnetic gearbox assembly 210 includes a winding circuit with a rotor winding (shown in more detail in Figures 3A-3C or 4A-4C). The magnetic gearbox assemblies 210 are part of the electric gearbox 110 and are separated from each other by an air gap 230 that is selectively bridged by an electromagnetic field between the magnetic gearbox assemblies 210.

[0045] 2A, the second magnetic gearbox assembly 210B defines a first cavity 240A (generally, cavity 240) in which the first magnetic gearbox assembly 210A is disposed. The first cavity 240A is coaxial with the spool shaft 160 such that the first magnetic gearbox assembly 210A and the second magnetic gearbox assembly 210B, and therefore the magnetic gearbox assembly 210, rotate about the shared axis of rotation 220 at different points along the length of the axis of rotation 220, away from the orbit of (i.e., out of physical contact with) the other magnetic gearbox assembly 210.

[0046] 2B, the first magnetic gearbox assembly 210A defines a second cavity 240B in which the second magnetic gearbox assembly 210B is positioned. The second cavity 240B is coaxial with the spool shaft 160 such that the first magnetic gearbox assembly 210A and the second magnetic gearbox assembly 210B, and therefore the magnetic gearbox assemblies 210, rotate about the shared axis of rotation 220 at different points along the length of the axis of rotation 220 such that they are spaced apart from (i.e., do not physically contact) the orbit of the other magnetic gearbox assembly 210.

[0047] 2C, the first magnetic gearbox assembly 210A and the second magnetic gearbox assembly 210B are positioned in a facing relationship with an air gap 230 between their physical components. The first magnetic gearbox assembly 210A and the second magnetic gearbox assembly 210B are coaxially aligned with one another, with the hub 152 and the first spool shaft 160A positioned facing one another, such that the magnetic field between the magnetic gearbox assemblies 210 is projected coaxially to couple the magnetic gearbox assemblies 210. The first magnetic gearbox assembly 210A is positioned parallel to the second magnetic gearbox assembly 210B such that the air gap 230 is perpendicular to the rotational axis 220 of the spool shaft 160 and defines a planar air gap 240C (rather than a cavity where one magnetic gearbox assembly 210 encases the other), through which the magnetic gearbox assemblies 210 are selectively coupled via a coaxial magnetic field.

[0048] The relative sizes and positions of the electromagnetically coupled components in Figures 2A-2C are shown for ease of identification and distinction. However, in various aspects, the relative size, shape, and orientation of these components can be modified based on the physical characteristics (e.g., length, thickness, circumference, gap distance, rotational torque, speed, operating temperature, etc.) of the turbofan engine 100 to which the components are attached, the desired power transfer characteristics (e.g., gear ratio, field strength, relative speed, etc.) of the extracted rotational energy, etc. The component lengths along the axis of the shaft 160, determined based on the vehicle's torque and / or power rating requirements from the turbofan engine 100, and the relative sizes and distances of the individual components, are sized to optimize torque production and speed from the turbofan engine 100 and power transfer efficiency in the electrical gearbox 110 within the physical confines of the turbofan engine 100. Thus, Figures 2A-2C are intended to illustrate concepts of operation, not necessarily specific implementations, and can be modified based on power requirements, thrust requirements, the specific fuel consumption of the turbofan engine 100, and material properties of the various components, to name a few considerations.

[0049] 3A-3C and 4A-4C illustrate various arrangements of the first magnetic gearbox assembly 210A relative to the second magnetic gearbox assembly 210B according to embodiments of the present disclosure. 3A-3C illustrate a winding circuit 310, including a rotor winding 330 and a switch 320, internal to a permanent magnet array 340, while 4A-4C illustrate the winding circuit 310 external to the permanent magnet array 340. While shown with an array having one pair of magnetic poles (i.e., one north (N) pole and one south (S) pole), the rotor winding 330 and permanent magnet array 340 may include additional pairs of magnetic poles in other embodiments.

[0050] Depending on the configuration of the first magnetic gearbox assembly 210A relative to the second magnetic gearbox assembly 210B (according to FIGS. 2A-2C), the first one of the winding circuits 310 and the permanent magnet array 340 are included in the first magnetic gearbox assembly 210A, and the second one of the winding circuits 310 and the permanent magnet array 340 are included in the second magnetic gearbox assembly 210B. For example, if the second magnetic gearbox assembly 210B encompasses the first magnetic gearbox assembly 210A (as in FIG. 2A), the second magnetic gearbox assembly 210B may include the winding circuit 310 (as in FIGS. 4A-4C) or the permanent magnet array 340 (as in FIGS. 3A-3C).

[0051] 3A-3C and 4A-4C are shown in a plane perpendicular to the spool shaft's axis of rotation 220, with the rotational speed of the inner element (i.e., winding circuit 310 in FIGS. 3A-3C or permanent magnet array 340 in FIGS. 4A-4C) designated as ωi, while the rotational speed of the outer element (i.e., winding circuit 310 in FIGS. 4A-4C or permanent magnet array 340 in FIGS. 3A-3C) designated as ωe. When switch 320 is closed, completing a circuit including rotor winding 330, rotation of permanent magnet array 340 relative to rotor winding 330 induces a current in winding circuit 310 that generates a magnetic field in rotor winding 330. The magnetic fields of permanent magnet array 340 and winding circuit 310 interact, resulting in the transfer of a rotational force (e.g., torque) from spool shaft 160 to fan 150.

[0052] 3A and 4A show the respective winding circuits 310 and permanent magnet arrays 340 in a neutral position, with the respective winding circuits 310 and permanent magnet arrays 340 not offset from one another. However, as the components rotate due to forces transmitted from the rotation of the spool shaft 160, the outer components may lag or lead by an angle θ. FIGS. 3B and 4B show the outer elements offset by an angle θ in the direction of rotation. lag (e.g., 0 radians < θ lag 3C and 4C show the respective winding circuits 310 and permanent magnet arrays 340 lagging the inner elements by an angle of θ lead (e.g., -π / 2 radians < θ). lead 3. The respective winding circuits 310 and permanent magnet arrays 340 are shown leading by 10 radians (<0 radians).

[0053] In one example, the first magnetic gearbox assembly 210A connected to the first spool shaft 160A includes a permanent magnet array 340 and is external to the second magnetic gearbox assembly 210B including the winding circuit 310 (e.g., per FIGS. 2A and 3A-3C). In that example, as in FIG. 3B, when the permanent magnet array 340 lags the rotor windings 330, a current is generated in the rotor windings 330, which in turn generates a rotor magnetic field that is pushed by the permanent magnetic field generated by the permanent magnet array 340. Similarly, as in FIG. 3C, when the permanent magnet array 340 leads the rotor windings 330, a current is generated in the rotor windings 330, which in turn generates a rotor magnetic field that is pulled by the permanent magnetic field inherent to the permanent magnet array 340. Thus, rotational energy is transferred from the first spool shaft 160A to the fan 150 without requiring an external power source to energize the rotor windings 330.

[0054] In another example, the first magnetic gearbox assembly 210A connected to the first spool shaft 160A includes a winding circuit 310 and is external to the second magnetic gearbox assembly 210B including the permanent magnet array 340 (e.g., per FIGS. 2A and 4A-4C). In that example, as in FIG. 4B, when the rotor windings 330 lag the permanent magnet array 340, current is generated in the rotor windings 330, which in turn generates a rotor magnetic field that is pushed by the permanent magnetic field generated by the permanent magnet array 340. Similarly, as in FIG. 4C, when the rotor windings 330 lead the permanent magnet array 340, current is generated in the rotor windings 330, which in turn generates a rotor magnetic field that is pulled by the permanent magnetic field inherent to the permanent magnet array 340. Thus, rotational energy is transferred from the first spool shaft 160A to the fan 150 without requiring an external power source to energize the rotor windings 330.

[0055] A switch 320 included in the winding circuit 310 selectively interconnects one end of the rotor winding 330 with the other end to open or close the winding circuit 310. When closed, the switch 320 allows current to flow through the rotor winding 330, generating a rotor magnetic field and thus allowing the permanent magnetic field to push or pull the rotor magnetic field. When open, the switch 320 interrupts the flow of current through the rotor winding 330, thereby disrupting the generation of the rotor magnetic field and thus decoupling the magnetic gearbox assembly 210. Depending on the frequency (and length) of the duty cycle at which the switch 320 is open or closed, the rotor winding 330 can alternately lag or lead the permanent magnet array 340. Regardless of whether the rotor winding 330 lags or leads the permanent magnet array 340, force is transmitted to rotate the fan 150 in the same direction as the first spool shaft 160A.

[0056] Torque is the rotational force applied to fan 150 from first spool shaft 160A and is proportional to the induced current in rotor winding 330. By controlling the duty cycle of switch 320, the average value of the induced current over time can be matched to the desired torque. For a given moment of inertia of rotor R, the dynamic equation governing its speed is given by Equation 1, where J is the rotor moment of inertia, T is the torque generated by magnetic field interaction, and b is the friction coefficient. J(dωR) / dt=T-bω R (1)

[0057] Assuming a constant friction coefficient b for a steady-state (i.e., non-accelerating) rotor, Equation 2 provides a simplified version of Equation 1. T=bω R (2)

[0058] The rotational speed of the fan 150 is therefore proportional to the average value of the induced current in the rotor winding 330 over time.

[0059] 5A-5C illustrate a speed controller 500 for an electric gearbox 110 according to an embodiment of the present disclosure. The speed controller 500 sets the duty cycle of a switch 320 to control the induced current in the rotor winding 330, thereby controlling the speed of the fan 150. The speed controller 500 is co-located with the winding circuit 310 and controls the switch 320 contained therein. FIG. 5A illustrates an embodiment in which the speed controller 500 is located on the fan 150 (i.e., when the first magnetic gearbox assembly 210A includes the winding circuit 310) and receives power from an external power source 580. FIG. 5B illustrates an embodiment in which the speed controller 500 is located on the first spool shaft 160A (i.e., when the second magnetic gearbox assembly 210B includes the winding circuit 310) and receives power from an external power source 580. In contrast to the embodiment discussed in connection with Figures 5A and 5B, Figure 5C shows an embodiment in which the speed controller 500 is located on the first spool shaft 160A (i.e., when the second magnetic gearbox assembly 210B includes the winding circuit 310) and receives power from a power supply 580 located on the spool shaft 160A, which transmits power to the fan 150 through the engine case and intervening spaces.

[0060] The speed controller 500 receives a reference (or target) speed for the fan 150 from the engine thrust controller 510 and a measured speed for the fan 150 from the speed sensor 520. In various embodiments, the engine thrust controller 510 is located in the nacelle 130 or on the body of the vehicle that controls the turbofan engine 100 and determines the reference speed for the fan 150 based on the operating conditions of the turbofan engine 100 (e.g., altitude, temperature, number of engines used by the vehicle, etc.) and the desired speed or thrust profile of the vehicle. In some embodiments, the engine thrust controller 510 transmits the reference speed to the speed controller 500 via contactless communication (e.g., optical or radio waves). Thus, embodiments may include a contactless transmitter 570A paired with a contactless receiver 570B used by the speed controller 500 to receive the reference speed.

[0061] Speed ​​sensor 520 measures the rotational speed of fan 150 and can include several different types of sensors located at various locations on turbofan engine 100. In one example, speed sensor 520 includes a Hall Effect sensor that measures the magnitude of a magnetic field (e.g., generated by a permanent magnet connected to fan 150) and tracks the rotational speed of fan 150 based on the frequency of periodic changes in the magnitude of that magnetic field. In another example, speed sensor 520 includes an inductive sensor that measures variations in magnetic flux in a generated or induced magnetic field due to changes in the proximity of elements of fan 150 (e.g., when fan blades 151 are angled), or a magnetic element included in first magnetic gearbox assembly 210A. In a further example, the speed sensor 520 includes an optical isolator sensor including an optical transmitter and an optical receiver for determining the speed of the fan 150 based on the frequency at which the transmitter and receiver align with each other (e.g., based on a transmitted light beam between the fan 150 and a transmitter / receiver separately located on the spool shaft 160) or based on a reflected signal (e.g., from a reflective surface of the fan 150 to a reflective pair of transmitter / receivers located on the spool shaft 160).

[0062] Comparator 530 compares the reference speed to the measured speed and provides the difference to a control loop 540, such as a proportional-integral-derivative (PID) controller, which uses the difference as feedback for how to adjust the duty cycle of switch 320. For example, if the difference indicates that the measured speed is slower than the reference speed, control loop 540 indicates that the duty cycle needs to be increased so that switch 320 remains closed longer, closes more frequently, or a combination thereof, compared to the current duty cycle. In another example, if the difference indicates that the measured speed is greater than the reference speed, control loop 540 indicates that the duty cycle needs to be decreased so that switch 320 remains open longer, opens more frequently, or a combination thereof, compared to the current duty cycle. Thus, switch 320 is controlled to selectively decouple or selectively couple magnetic gearbox assembly 210 of electric gearbox 110 in response to the duty cycle indicated by control loop 540.

[0063] In various aspects, the output from control loop 540 passes through integrator 550 to eliminate spikes in the output, maintain the output within a specified range, prevent oscillatory changes (e.g., alternating small increases and decreases in duty cycle below a threshold adjustment size or within a specified time frame), and reduce jerk or distortion of fan 150 through rapid or frequent changes in duty cycle.

[0064] A power switch driver 560 receives the output from the speed controller 500 and implements the duty cycle of the switch 320. In various embodiments, the power switch driver 560 is powered by current generated in the winding circuit 310 or another inductive loop and opens and closes the switch 310 according to a selected duty cycle. In various embodiments, the power switch driver 560 provides power to open a normally closed switch that closes when power is removed, provides power to close a normally open switch that opens when power is removed, or provides power to change the state of a switch that remains in its current state (i.e., open or closed) when power is removed.

[0065] 5A and 5B, power supplied to the electrical components of the speed controller 500 and power switch driver 560 is received from a power source 580 external to the spool shaft 160 and electric gearbox 110, which in some embodiments may be mounted to the turbine enclosure 120 or nacelle 130. When mounted external to the electric gearbox 110, power is transmitted wirelessly across an air gap from a transmitter 590A located with the power source 580 to a power receiver 590B located on the spool shaft 160, fan, or electric gearbox 110. In various embodiments, the power transmitter 590A and power receiver 590B may include various near-field coupling devices (e.g., inductive or capacitive coupling devices) or far-field coupling devices (such as microwave and laser power beaming devices), depending on the distance between the power transmitter 590A and the power receiver 590B and the intervening objects (including additional power transmitters / receivers for transferring power between different locations).

[0066] In Figure 5C, power supplied to the electrical components of the speed controller 500 and power switch driver 560 is received from a power source 580 that is co-located with the spool shaft 160 or the electrical gearbox 110. In various embodiments, the power source 580 of Figure 5C can be a battery or other power storage and release device, such as a supercapacitor. In some embodiments, the power source 580 of Figure 5C receives input power from a generator 190 connected to the interface between the first spool shaft 160A and the second spool shaft 160B, as described in more detail with respect to Figure 1C.

[0067] FIG. 6 is a flowchart of a method 600 for controlling a turbofan engine 100 having an electric gearbox 110 according to an embodiment of the present disclosure.

[0068] Method 600 begins at block 610, where a spool shaft 160 of a turbofan engine 100 rotates. In a turbofan engine 100, an operator can rotate the spool shaft 160 by engaging the turbofan engine 100 to generate thrust for the vehicle; rotational energy is induced in the spool shaft 160 by combustion of fuel in the combustion chamber, which expels exhaust through the turbine section 124, thus rotating the spool shaft 160 corresponding to the turbine 180. Depending on the number of spool shafts 160 in the turbofan engine 100, the thrust requirements of the vehicle using the turbofan engine 100, the altitude of the vehicle using the turbofan engine 100, etc., the spool shafts 160 can rotate at a variety of different speeds.

[0069] At block 620, the electric gearbox 110 transfers rotational energy from the first spool shaft 160A of the turbofan engine 100 to the fan 150. The first magnetic gearbox assembly 210A of the electric gearbox 110 is connected to the first spool shaft 160A and includes one of the winding circuit 310 or the permanent magnet array 340. The second magnetic gearbox assembly 210B of the electric gearbox 110 is connected to the fan 150 and includes one of the winding circuit 310 or the permanent magnet array 340 that is different from that included in the first magnetic gearbox assembly 210A. The magnetic gearbox assemblies 210 are separated from each other via an air gap 230, but are (selectively) electromagnetically coupled through the air gap 230 via the rotor magnetic field selectively generated by the rotor windings 330 and the permanent magnetic field generated by the permanent magnet array 340.

[0070] Rotating the first spool shaft 160A (and connected first magnetic gearbox assembly 210A) at a first rotational speed induces a current in the rotor winding 330 of the winding circuit 310 when the switch 320 therein is closed. When a current is induced in the rotor winding 330, the rotor winding 330 generates a rotor magnetic field that is pushed or pulled in the direction of rotation of the first spool shaft 160A by the permanent magnetic field associated with the permanent magnet array 340. Thus, the rotational energy of the first spool shaft 160A connected to the fan 150 is transferred through the first magnetic gearbox assembly 210A to the second magnetic gearbox assembly 210B, thus causing the fan 150 to rotate with the first spool shaft 160A.

[0071] In block 630 , the fan 150 rotates at a second rotational speed based on the first rotational speed of the first spool shaft 160 A and the duty cycle of the switch 320 selected by the speed controller 500 .

[0072] In block 640, the speed controller 500 measures a second rotational speed of the fan 150. In various embodiments, a speed sensor 520 (such as a Hall Effect sensor, an inductive sensor, an opto-isolator sensor, etc.) measures the speed of the fan 150, and the speed controller 500 compares the measured speed to a reference (or target) speed at which the fan 150 is set to rotate. The speed controller 500 determines whether the difference between the reference speed of the fan 150 and the measured speed of the fan 150 is outside a threshold range (e.g., Δ(ω reference , ω measured )±ω reference % of the maximum speed of the fan 150. Based on this, the controller 300 determines whether to adjust the duty cycle of the switch 320 (and therefore the speed of the fan 150).

[0073] At block 650, the speed controller 500 adjusts the portion of rotational energy transferred to the fan 150 based on the duty cycle of the switch 320 in the winding circuit 310 of the electric gearbox 110. By increasing the relative time that the switch 320 is closed, the speed controller 500 increases the portion of rotational energy transferred from the spool shaft 160 to the fan 150, thereby increasing the speed of the fan 150. Similarly, by decreasing the relative time that the switch 320 is open, the speed controller 500 decreases the portion of rotational energy transferred from the spool shaft 160 to the fan 150, thereby decreasing the speed of the fan 150. If the reference speed is greater than the measured speed and exceeds the threshold, the method 600 returns to block 630 where the duty cycle of the switch 320 is increased, thereby increasing the speed of the fan 150. If the reference speed is less than the measured speed and exceeds the threshold, the method 600 returns to block 630 where the duty cycle of the switch 320 is decreased, thereby decreasing the speed of the fan 150. Thus, the method 600 can continue to control the speed of the fan 150 with respect to the updated reference speed, changes in environmental conditions, changes in the rotational speed of the spool shaft 160, and combinations thereof.

[0074] FIG. 7 is a flowchart of a method 700 for manufacturing a turbofan engine 100 having an electric gearbox 110 according to an embodiment of the present disclosure.

[0075] At block 710, the fabricator attaches the first magnetic gearbox assembly 210A to the first spool shaft 160A of the turbofan engine 100.

[0076] At block 720, the fabricator attaches the second magnetic gearbox assembly 210B to the fan 150 of the turbofan engine 100.

[0077] The first magnetic gearbox assembly 210A includes a first one of the winding circuits 310 and a permanent magnet array 340, while the second magnetic gearbox assembly 210B includes a second one of the winding circuits 310 that is different from the first one included in the first magnetic gearbox assembly 210A and a permanent magnet array 340. The first magnetic gearbox assembly 210A and the second magnetic gearbox assembly 210B define an air gap 230 between each other such that the first magnetic gearbox assembly 210A and the second magnetic gearbox assembly 210B are not in physical contact with each other. Rather, the first magnetic gearbox assembly 210A and the second magnetic gearbox assembly 210B are configured to selectively come into magnetic contact with each other. In various embodiments, the first magnetic gearbox assembly 210A is disposed within a first cavity 240A defined by the second magnetic gearbox assembly 210B (per FIG. 2A ), the second magnetic gearbox assembly 210B is disposed within a second cavity 240B defined by the first magnetic gearbox assembly 210A, or the magnetic gearbox assemblies 210 are disposed parallel to one another and define an air gap 230 perpendicular to the rotational axis 220 of the spool shaft 160 (per FIG. 2C ).

[0078] At block 730, the fabricator installs a speed sensor 520 for the fan 150 of the turbofan engine 100 to monitor the rotational speed of the fan 150. The speed sensor 520 may include various types of speed sensing or measuring devices, including but not limited to: Hall effect sensors, inductive sensors, and optical isolator sensors. In various aspects, the speed sensor may include a component attached to one or more of the fan 150, the first spool shaft 160A, the turbine enclosure 120, the nacelle 130, or other components of the turbofan engine 100.

[0079] At block 740, the fabricator couples the speed controller 500 to the speed sensor 520 and the winding circuit 310. The speed controller 500 is configured to adjust the duty cycle of the switch 320 included in the winding circuit 310 based on the difference between the rotational speed of the fan 150 measured by the speed sensor 520 and the desired speed of the fan 150, as indicated by the engine thrust controller 510 being in contactless communication with the speed controller 500. The speed controller 500 is located on the fan 150 when the first magnetic gearbox assembly 210A includes the winding circuit 310, or on the first spool shaft 160A when the second magnetic gearbox assembly 210B includes the winding circuit 310.

[0080] 8A illustrates a first component configuration 800A of a generator 190 according to an embodiment of the present disclosure. A first rotor assembly 810A is connected to a second (high-pressure) compressor 170B, which in turn is connected to the first (low-pressure) compressor 170A at the interface between the two compressors 170A-B. In various embodiments, the rotor assemblies 810A-B are connected to one or more blades of the associated compressor 170, to the ring / connection point of the blade to the associated spool shaft 160, or to the associated spool shaft 160. The rotor assemblies 810A-B position the various electromagnetic components of the generator 190 at known distances and orientations relative to each other, the shaft 160, and the compressor 170.

[0081] 8A , first rotor assembly 810A includes permanent magnets 820 that generate generator magnetic field 815. Permanent magnets 820 magnetically couple generator magnetic field 815 radially through an air gap defined coaxially on shaft 160 to generator armature windings 830 included in second rotor assembly 810B. In various aspects, permanent magnets 820 may include multiple magnets arranged circumferentially around shaft 160 to emit multiple generator magnetic fields 815.

[0082] The second rotor assembly 810B includes concentrically and radially arranged generator armature windings 830, but is not in physical contact with the permanent magnets 820 or the shaft 160, and positions the generator armature windings 830 within a predetermined field strength of the generator magnetic field 815. Thus, the generator magnetic field 815 radially couples the permanent magnets 820 and the generator armature windings 830.

[0083] 8B illustrates a second component configuration 800B of a generator 190 according to an embodiment of the present disclosure. A first rotor assembly 810A is connected to a higher pressure second compressor 170B, which in turn is connected to a low pressure first compressor 170A at the interface between the two compressors 170. In various embodiments, the rotor assemblies 810A-B are connected to one or more blades of the associated compressor 170, to the ring / connection point of the blade to the associated spool shaft 160, or to the associated spool shaft 160. The rotor assemblies 810A-B position the various electromagnetic components of the generator 190 at known distances and orientations relative to each other, the shaft 160, and the compressor 170.

[0084] 8B, the first rotor assembly 810A includes permanent magnets 820 that generate a generator magnetic field 815. The permanent magnets 820 emit the generator magnetic field 815 through an air gap defined in a plane that intersects the axis of rotation of the shaft 160, magnetically coupling the permanent magnets 820 to generator armature windings 830 included in the second rotor assembly 810B. While shown as defining the air gap in a plane orthogonal to the axis of rotation (e.g., for a coaxial magnetic linkage between the permanent magnets 820 and the generator armature windings 830), in other embodiments, the air gap can be defined at other angles relative to the shaft 160. In various embodiments, the permanent magnets 820 can include multiple magnets arranged radially around the shaft 160 to emit multiple generator magnetic fields 815.

[0085] The second rotor assembly 810B is radially disposed about, but not physically contacting, the shaft 160 and includes generator armature windings 830 that are planetarily disposed relative to the permanent magnets 820. The relative positions and lengths of the rotor assemblies 810A-B position the generator armature windings 830 within a predetermined field strength of the generator magnetic field 815. Thus, the generator magnetic field 815 axially couples the permanent magnets 820 and the generator armature windings 830.

[0086] During operation of the turbofan engine 100 in which the components are disposed, the rotational force imparted by the turbine 180 causes the compressor 170 and attached EM components to rotate relative to each other and relative to the stationary turbine enclosure 120. Due to the difference in rotational speed between the high-pressure compressor 170B and the low-pressure compressor 170A, the generator magnetic field 815 rotates relative to the generator armature windings 830. Electrical energy is therefore extracted from the rotational force of the shaft 160 and transferred to power the speed controller 500 of the electrical gearbox 110 (e.g., as the power supply 580), among other components.

[0087] The relative size and location of the electromagnetically coupled components in Figures 8A and 8B are shown for ease of identification and distinction. However, in various aspects, the relative size, shape, and orientation of these components can be varied based on the physical characteristics of the turbofan engine 100 to which the components are attached (e.g., length, thickness, circumference, gap distance, rotational torque, speed, operating temperature), the power characteristics required for the extracted power (e.g., number of power phases, voltage / current levels), etc. The length of the components along the axis of the shaft 160 is determined by the vehicle's torque and / or power rating requirements from the turbofan engine 100, and the relative size and distance of the individual components are sized to optimize torque production and speed from the turbofan engine 100 and power transfer efficiency at the generator 190 within the physical confines of the turbofan engine 100. Thus, Figures 8A and 8B are intended to illustrate concepts of operation and can be varied based on the power requirements, thrust requirements, specific fuel consumption of the turbofan engine 100, and material properties of the various components, not necessarily any particular implementation. For example, if radial space along the length of the compressor 170 blades is more readily available, or if axial space between compressors 170 is more readily available according to FIG. 8B, a fabricator can design permanent magnets 820 and generator armature windings 830 according to FIG. 8A.

[0088] Various embodiments are referenced in this disclosure. However, it should be understood that the disclosure is not limited to the specific described embodiments. Instead, any combination of the following features and elements, whether associated with a different embodiment, is contemplated for implementing and practicing the teachings provided herein. Furthermore, when elements of an embodiment are described in the form of "at least one of A and B," it is understood that embodiments including only element A, including only element B, and including elements A and B are respectively contemplated. Furthermore, while some embodiments may achieve advantages over other possible solutions and / or the prior art, whether or not a particular advantage is achieved by a given embodiment does not limit the disclosure. Accordingly, the embodiments, features, aspects, and advantages disclosed herein are merely exemplary and should not be considered elements or limitations of the appended claims unless expressly recited in the claims. Similarly, references to "the present invention" should not be construed as generalizing all inventive subject matter disclosed herein, and should not be considered an element of or limiting the scope of the appended claims unless expressly recited in the claim(s).

[0089] As will be appreciated by one skilled in the art, the aspects described herein may be embodied as a system, method, or computer program product. Accordingly, the aspects may take the form of entirely hardware aspects, entirely software aspects (including firmware, resident software, microcode, etc.), or aspects combining software and hardware aspects, all of which may be broadly referred to herein as "circuits," "modules," or "systems." Furthermore, the aspects described herein may take the form of a computer program product embodied in one or more computer-readable storage medium(s) having computer-readable program code embodied therein.

[0090] The program code embodied in the computer readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, fiber optic cable, RF, etc., or any suitable combination thereof.

[0091] Computer program code for carrying out the steps of aspects of the present disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" programming language or similar programming languages. The program code may run entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet Service Provider).

[0092] Aspects of the present disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to aspects of the present disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, executed by a processor of the computer or other programmable data processing apparatus, create means for performing the functions / acts specified in the blocks of the flowchart illustrations and / or block diagrams.

[0093] These computer program instructions may also be stored on a computer-readable medium that can direct a computer, other programmable data processing device, or other device to function in a particular manner, such that the instructions stored on the computer-readable medium produce an article of manufacture containing instructions that implement the functions / acts specified in the flowchart and / or block diagram blocks.

[0094] Computer program instructions may also be loaded into a computer, other programmable data processing apparatus, or other device to cause the computer, other programmable data processing apparatus, or other device to perform a series of operational steps to generate a computer-implemented process such that the instructions, executed on the computer, other programmable data processing apparatus, or other device, provide a process for implementing the functions / acts specified in the flowchart and / or block diagram blocks.

[0095] The flowchart diagrams and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various aspects of the present disclosure. As such, each block in the flowchart diagrams and block diagrams may represent a module, segment, or portion of code, including one or more executable instructions for implementing particular logical function(s). It should also be noted that in some alternative implementations, the functions shown in the blocks may differ from the order shown in the figures. For example, two blocks shown in succession may actually be executed simultaneously, or the blocks may be executed in the reverse order or out of order, depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flowchart diagrams, and combinations of blocks in the block diagrams and / or flowchart diagrams, may be implemented by a special-purpose hardware-based system that performs particular functions or functions, or by a combination of special-purpose hardware and computer instructions.

[0096] Terms 1. A system comprising: a first magnetic gearbox assembly (210A) connected to a fan (150) of the turbofan engine (100); a second magnetic gearbox assembly (210B) connected to the spool shaft (160) of the turbofan engine (100); a speed controller (500) configured to adjust the rotational speed of the fan (150) based on the rotational speed of the spool shaft (160) by selectively coupling and decoupling the first magnetic gearbox assembly (210A) with the second magnetic gearbox assembly (210B); Including, the system.

[0097] 2. The first magnetic gearbox assembly (210A) includes a permanent magnet array (340); The second magnetic gearbox assembly (210B) includes a rotor winding (330) separated from a permanent magnet array (340) by an air gap (230); The system of clause 1, wherein the speed controller (500) is configured to selectively couple and decouple the first magnetic gearbox assembly (210A) with the second magnetic gearbox assembly (210B) by opening and closing a switch (320) in a winding circuit (310) having a rotor winding (330).

[0098] 3. The second magnetic gearbox assembly (210B) includes a permanent magnet array (340); The first magnetic gearbox assembly (210A) includes a rotor winding (330) separated from a permanent magnet (340) array by an air gap (230); The system of clause 1, wherein the speed controller (500) is configured to selectively couple and decouple the first magnetic gearbox assembly (210A) with the second magnetic gearbox assembly (210B) by opening and closing the switch (320) of the winding circuit (310) having the rotor winding (330).

[0099] 4. The system of any one of clauses 1 to 3, wherein the first magnetic gearbox assembly (210A) is coaxially positioned within the cavity (240) defined by the second magnetic gearbox assembly (210B).

[0100] 5. The system of any one of clauses 1 to 4, wherein a second magnetic gearbox assembly (210B) is coaxially positioned within the cavity (240) defined by the first magnetic gearbox assembly (210A).

[0101] 6. The system of any one of clauses 1 to 5, wherein the first magnetic gearbox assembly (210A) and the second magnetic gearbox assembly (210B) are electromagnetically coupled via a coaxial magnetic field.

[0102] 7. The system of any one of clauses 1 to 6, wherein the speed controller (500) is configured to isolate the first magnetic gearbox assembly (210A) from the second magnetic gearbox assembly (210B) by opening at least the switch (310) with a switch (560) driver powered by a current generated by the first magnetic gearbox assembly (210A) rotating relative to the second magnetic gearbox assembly (210B).

[0103] 8. The system of any one of clauses 1 to 7, wherein the speed controller (500) is configured to adjust the rotational speed of the fan (150) based on a difference between the reference speed (150) of the fan and the measured speed (150) of the fan.

[0104] 9. The speed controller (500) further includes a speed sensor (520), wherein the speed sensor (520): Hall effect sensors; inductive sensors; or Optical Isolator Sensor 9. The system of any one of clauses 1 to 8, including at least one of:

[0105] 10. The system of any one of clauses 1 to 9, further comprising an engine thrust controller (510) configured to transmit a reference speed to the speed controller (500) via contactless communication.

[0106] 11. A turbofan engine comprising: with fans (150); A turbine enclosure (120) comprising: air intake at the upstream end (121); a compression section (122) downstream of the air intake (121); a combustion section (123) downstream of the compression section (122); a turbine section (124) downstream of the combustion section (123); and Downstream exhaust (125) a turbine enclosure (120) including: a first spool shaft (160A) coupled to a first compressor (170A) of the compression section (122) and a first turbine (180A) of the turbine section (124); an electric gearbox (110) located upstream of the turbine enclosure (120), the electric gearbox (110) including a first magnetic gearbox assembly (210A) connected to the fan (150) and a second magnetic gearbox assembly (210B) connected to the first spool shaft (160A), the electric gearbox (110) configured to transfer rotational energy from the first spool shaft (160A), which rotates at a second rotational speed, to the fan (150), which rotates at a first rotational speed, via an air gap (230) between the first magnetic gearbox assembly (210A) and the second magnetic gearbox assembly (210B); a speed controller (500) coupled to the electric gearbox (110) and configured to selectively couple and decouple the first magnetic gearbox assembly (210A) with the second magnetic gearbox assembly (210B) through the air gap (230) to regulate the first rotational speed to a variable fan reference speed while maintaining the second rotational speed at a constant speed; Including turbofan engines.

[0107] 12. The first magnetic gearbox assembly (210A) includes a permanent magnet array (340) and the second magnetic gearbox assembly (210B) includes a winding circuit (310) defining a rotor winding (330); 12. The turbofan engine of claim 11, wherein the speed controller is configured to reduce a duty cycle of a switch in the winding circuit to reduce the first rotational speed relative to the second rotational speed.

[0108] 13. The first magnetic gearbox assembly (210A) includes a winding circuit (310) defining a rotor winding (330), and the second magnetic gearbox assembly (210B) includes a permanent magnet array (340); and 13. The turbofan engine of claim 11 or 12, wherein the speed controller is configured to reduce a duty cycle of the switch in the winding circuit to reduce the first rotational speed relative to the second rotational speed.

[0109] 14. The air gap (230) is: coaxial with the first spool shaft (160A) defined by disposing a second magnetic gearbox assembly (210B) in a first cavity (240A) defined by the first magnetic gearbox assembly (210A); coaxial with the first spool shaft (160A) defined by the first magnetic gearbox assembly (210A) within the second cavity (240B) defined by the second magnetic gearbox assembly (210B); and perpendicular to the axis of rotation (220) of the first spool shaft (160A) defined by placing the first magnetic gearbox assembly (210A) parallel to the second magnetic gearbox assembly (210B); The turbofan engine (100) of any one of clauses 11 to 13, which is one of the

[0110] 15. A method (600) comprising: Rotating (610) a spool shaft (160) of a turbofan engine (100) at a first rotational speed; transmitting (620) rotational energy from a spool shaft (160) to a fan (150) of a turbofan engine (100) via an electric gearbox (110); adjusting (650) a portion of the rotational energy transferred to the fan (150) based on the duty cycle of a switch (310) in a winding circuit (310) of the electric gearbox (110); rotating (630) the fan (150) at a second rotational speed based on the duty cycle; A method (600) comprising:

[0111] 16. Electric gearbox (110): a first magnetic gearbox assembly (210A) including a winding circuit (310) and a switch (310), the first magnetic gearbox assembly (210A) being coupled to the spool shaft (160); and a second magnetic gearbox assembly (210B) including a permanent magnet array (340), coupled to the fan (150), and separated from the first magnetic gearbox assembly (210A) by an air gap (230); The method of clause 15 (600) includes:

[0112] 17. Electric gearbox: a first magnetic gearbox assembly (210A) including a winding circuit (310) and a switch (310) and coupled to the fan (150); and a second magnetic gearbox assembly (210B) including a permanent magnet array (340), coupled to the spool shaft (160), and separated from the first magnetic gearbox assembly by an air gap; (600) a method of clause 15 or 16, including

[0113] 18. Measuring a second rotational speed; adjusting the duty cycle of the switch (320) in response to the second rotational speed of the fan (150) not matching within a threshold of the reference speed while continuing to rotate the spool shaft (160) at the first rotational speed; 18. The method (600) of any one of clauses 15 to 17, further comprising:

[0114] 19. A method (700) comprising: Attaching (710) a first magnetic gearbox assembly (210A) to a first spool shaft (160A) of a turbofan engine (100), the first magnetic gearbox assembly (210A) including a first of a winding circuit (310) defining a rotor winding (330) having a selectively configurable switch (320) and a permanent magnet array (340); mounting (720) a second magnetic gearbox assembly (210B) including a winding circuit (310) and a second permanent magnet array (340) different from the first to a fan (150) of the turbofan engine (100), the second magnetic gearbox assembly (210A) and the second magnetic gearbox assembly (210B) defining an air gap (230) therebetween; attaching a speed sensor (520) to the turbofan engine (100) to monitor the rotational speed of the fan (150); coupling (740) a speed controller (500) to the speed sensor (520) and the winding circuit (310), the speed controller (500) being configured to adjust the duty cycle of the selectively configurable switch (320) based on a difference between the rotational speed of the fan (150) and a reference speed of the fan (150); and A method (700).

[0115] 20. Installing the first magnetic gearbox assembly (210A) and installing the second magnetic gearbox assembly (210B): disposing a first magnetic gearbox assembly (210A) in a first cavity (240A) defined by a second magnetic gearbox assembly (210B), wherein an air gap (230) is coaxial with a first spool shaft (160A); disposing the first magnetic gearbox assembly (210A) in the first cavity (240A); disposing a second magnetic gearbox assembly (210B) in a second cavity (240B) defined by the first magnetic gearbox assembly (210A), wherein the air gap (230) is coaxial with the first spool shaft (160A); and Positioning the first magnetic gearbox assembly (210A) in parallel with the second magnetic gearbox assembly (210B), wherein the air gap (230) is perpendicular to the rotational axis (220) of the first spool shaft (160A). Positioning the first magnetic gearbox assembly (210A) in parallel with the second magnetic gearbox assembly (210B). The method (700) of clause 19, wherein the air gap is defined by one of the following:

[0116] 21. A processing system comprising: a memory containing computer-executable instructions; a processor configured to execute computer-executable instructions to cause a processing system to perform the method of any one of clauses 15 to 20; a processing system including:

[0117] 22. A non-transitory computer-readable medium containing computer-executable instructions that, when executed by a processor of a processing system, cause the processing system to perform the method of any one of clauses 15 to 20.

[0118] 23. A computer program product embodied on a computer-readable storage medium comprising code for carrying out the method of any one of clauses 15 to 20.

[0119] While the foregoing is directed to aspects of the disclosure, other and further aspects of the disclosure may be devised without departing from the basic scope thereof, the scope of which is defined by the following claims.

Claims

1. 1. A system comprising: a first magnetic gearbox assembly (210A) connected to a fan (150) of the turbofan engine (100); a second magnetic gearbox assembly (210B) connected to a spool shaft (160) of the turbofan engine (100); a speed controller (500) configured to adjust the rotational speed of the fan (150) based on the rotational speed of the spool shaft (160) by selectively coupling and decoupling the first magnetic gearbox assembly (210A) with the second magnetic gearbox assembly (210B); Including, the system.

2. the first magnetic gearbox assembly (210A) includes a permanent magnet array (340); the second magnetic gearbox assembly (210B) includes a rotor winding (330) separated from the permanent magnet array (340) by an air gap (230); 2. The system of claim 1, wherein the speed controller (500) is configured to selectively couple and decouple the first magnetic gearbox assembly (210A) with the second magnetic gearbox assembly (210B) by opening and closing a switch (320) in a winding circuit (310) having the rotor winding (330).

3. the second magnetic gearbox assembly (210B) includes a permanent magnet array (340); the first magnetic gearbox assembly (210A) includes a rotor winding (330) separated from the permanent magnet array (340) by an air gap (230); 3. The system of claim 1, wherein the speed controller is configured to couple and decouple the first magnetic gearbox assembly with the second magnetic gearbox assembly by opening and closing a switch in a winding circuit having the rotor winding.

4. 4. The system of claim 1, wherein the first magnetic gearbox assembly (210A) is coaxially positioned within a cavity (240) defined by the second magnetic gearbox assembly (210B).

5. 5. The system of claim 1, wherein the second magnetic gearbox assembly (210B) is coaxially positioned within a cavity (240) defined by the first magnetic gearbox assembly (210A).

6. 6. The system of claim 1, wherein the first magnetic gearbox assembly (210A) and the second magnetic gearbox assembly (210B) are electromagnetically coupled via a coaxial magnetic field.

7. 7. The system of claim 1, wherein the speed controller is configured to decouple the first magnetic gearbox assembly from the second magnetic gearbox assembly by opening at least a switch via a switch driver powered by a current generated by the first magnetic gearbox assembly rotating relative to the second magnetic gearbox assembly.

8. 8. The system of claim 1, wherein the speed controller is configured to adjust the rotational speed of the fan based on a difference between a reference speed of the fan and a measured speed of the fan.

9. The speed controller (500) further includes a speed sensor (520), the speed sensor (520) detecting: Hall effect sensors; an inductive sensor; or Optical isolator sensor, The system of claim 1 , further comprising at least one of:

10. The system of claim 8 , further comprising an engine thrust controller (510) configured to transmit the reference speed to the speed controller (500) via contactless communication.

11. 11. The system of claim 1, further comprising the speed controller configured to selectively couple and decouple the first magnetic gearbox assembly with the second magnetic gearbox assembly through an air gap to regulate a first rotational speed to a variable fan reference speed while maintaining a second rotational speed at a constant speed.

12. Rotating (610) a spool shaft (160) of a turbofan engine (100) at a first rotational speed; transmitting (620) rotational energy from the spool shaft (160) to a fan (150) of the turbofan engine (100) via an electric gearbox (110); adjusting (650) a portion of the rotational energy transferred to the fan (150) based on a duty cycle of a switch (320) in a winding circuit (310) of the electric gearbox (110); rotating (630) the fan (150) at a second rotational speed based on the duty cycle; The method (600) includes:

13. The electric gearbox (110) comprises: a first magnetic gearbox assembly (210A) including the winding circuit (310) and the switch (320) and coupled to the spool shaft (160); and a second magnetic gearbox assembly (210B) including a permanent magnet array (340), coupled to the fan (150) and separated from the first magnetic gearbox assembly (210A) by an air gap (230); 13. The method (600) of claim 12, comprising:

14. 2. The electric gearbox comprising: a first magnetic gearbox assembly (210A) including the winding circuit (310) and the switch (320) and coupled to the fan (150); and a second magnetic gearbox assembly (210B) including a permanent magnet array (340), coupled to said spool shaft (160) and separated from said first magnetic gearbox assembly by an air gap; 14. The method (600) of claim 12 or 13, comprising:

15. measuring the second rotational speed; adjusting the duty cycle of the switch (320) while continuing to rotate the spool shaft (160) at the first rotational speed in response to the second rotational speed not matching within a threshold of a reference speed of the fan (150); 15. The method (600) of any one of claims 12 to 14, further comprising:

16. 1. A method for making a system comprising: attaching a first magnetic gearbox assembly to a first spool shaft of the turbofan engine, the first magnetic gearbox assembly having a selectively configurable switch and including a first one of the winding circuits defining a rotor winding and a permanent magnet array; mounting a second magnetic gearbox assembly to the fan of the turbofan engine, the second magnetic gearbox assembly including the permanent magnet array and a second winding circuit different from the first winding circuit, the first magnetic gearbox assembly and the second magnetic gearbox assembly defining an air gap therebetween; mounting a speed sensor (520) on the turbofan engine to monitor the rotational speed of the fan; coupling a speed controller to the speed sensor and the winding circuit, the speed controller being configured to adjust a duty cycle of the selectively configurable switch based on a difference between a rotational speed of the fan and a reference speed of the fan; A method comprising:

17. Attaching the first magnetic gearbox assembly and attaching the second magnetic gearbox assembly includes: disposing the first magnetic gearbox assembly in a first cavity defined by the second magnetic gearbox assembly, the air gap being coaxial with the first spool shaft; disposing the second magnetic gearbox assembly in a second cavity defined by the first magnetic gearbox assembly, the air gap being coaxial with the first spool shaft; and positioning the first magnetic gearbox assembly in parallel with the second magnetic gearbox assembly, the air gap being perpendicular to an axis of rotation of the first spool shaft; The method of claim 16 , wherein the air gap is defined by one of:

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