Generator

Abstract

A generator assembly for an aircraft is provided. The generator assembly includes a main generator having a main rotor and a main stator, the main stator including a first three-phase winding and a second three-phase winding each configured to have a voltage induced therein by the main rotor, the first three-phase winding and the second three-phase winding defining a phase shift between the first three-phase winding and the second three-phase winding greater than zero degrees.

Description

[0001] This application is a divisional application of the invention patent application with application number 202110372253.1 filed on April 7, 2021 and invention name “Generator”. Technical Field

[0002] The present subject matter generally relates to generator assemblies, such as generator assemblies for aircraft electrical systems. Background Art

[0003] For some aircraft, a generator may be included to provide a DC power output to power various DC aircraft loads. For example, a DC generator may provide power to various control systems, cabin systems, and / or propulsion systems (e.g., electric propulsion systems) of the aircraft. Due to ripple issues at the generator output, these generators typically include relatively large capacitors to minimize large ripple. Including relatively large capacitors may undesirably increase the weight of the electrical system. Therefore, a DC generator that can provide power with reduced ripple using smaller capacitors would be useful. Summary of the Invention

[0004] Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

[0005] In one aspect of the present disclosure, a generator assembly for an aircraft is provided. The generator assembly includes a main generator, the main generator including a main rotor and a main stator, the main stator including a first three-phase winding and a second three-phase winding, the first three-phase winding and the second three-phase winding each configured to have a voltage induced therein by the main rotor, and a phase shift greater than zero degrees is defined between the first three-phase winding and the second three-phase winding.

[0006] These and other features, aspects and advantages of the present invention will be better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A full and enabling disclosure of the invention, including the best mode thereof, to one skilled in the art is set forth in the specification, which refers to the accompanying drawings, in which:

[0008] Figure 1 is a top view of an aircraft according to various exemplary embodiments of the present disclosure.

[0009] Figure 2 is a schematic cross-sectional view of a gas turbine engine according to an exemplary aspect of the present disclosure.

[0010] Figure 3 is a side view of a generator assembly according to an exemplary embodiment of the present disclosure.

[0011] Figure 4 yes Figure 3 Schematic diagram of an exemplary generator assembly. DETAILED DESCRIPTION

[0012] Reference will now be made in detail to the present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. The same or similar designations have been used in the drawings and the description to refer to the same or similar parts of the invention.

[0013] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of each component.

[0014] The terms "forward" and "aft" refer to relative positions within a component or system and refer to the normal operating attitude of the component or system. For example, with respect to a gas turbine engine, forward refers to a position closer to the inlet of the gas turbine engine, while aft refers to a position closer to the exhaust of the gas turbine engine.

[0015] The terms "coupled," "fixed," "attached," and the like refer to both direct coupling, fixing, or attachment, as well as indirect coupling, fixing, or attachment through one or more intermediate components or features, unless otherwise stated.

[0016] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0017] As used herein throughout the specification and claims, approximating language is used to modify any quantitative representation that can be permissibly varied without resulting in a change in the basic function to which it is related. Accordingly, a value modified by one or more terms such as "about," "approximately," and "substantially" is not limited to the precise value specified. In at least some cases, approximating language may correspond to the precision of an instrument used to measure a value, or the precision of a method or machine used to construct or manufacture a component and / or system. For example, approximating language may refer to within 10%.

[0018] Here and throughout the specification and claims, range limitations are combined and interchanged, and unless context or language indicates otherwise, these ranges are identified and include all sub-ranges contained therein. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

[0019] Referring now to the drawings, in which like reference numerals refer to like elements throughout, Figure 1 A top view of an exemplary aircraft 10 is provided, which may incorporate various embodiments of the present invention. Figure 1 As shown, the aircraft 10 defines a longitudinal centerline 14 extending therethrough, a transverse direction L, a vertical direction (not shown; perpendicular to the transverse direction L and the longitudinal centerline 14), a front end 16, and a rear end 18. In addition, the aircraft 10 includes a fuselage 12 extending longitudinally from the front end 16 of the aircraft 10 toward the rear end 18 of the aircraft 10, and a pair of wings 20. As used herein, the term "fuselage" generally includes the entire body of the aircraft 10, such as the tail of the aircraft 10. A first such wing 20 extends laterally outward from a port side 22 of the fuselage 12 relative to the longitudinal centerline 14, while a second such wing 20 extends laterally outward from a starboard side 24 of the fuselage 12 relative to the longitudinal centerline 14. Each wing 20 of the depicted exemplary embodiment includes one or more leading edge flaps 26 and one or more trailing edge flaps 28. The aircraft 10 also includes a vertical stabilizer 30 having rudder flaps (not shown) for yaw control, and a pair of horizontal stabilizers 34 each having elevator flaps 36 for pitch control. The fuselage 12 further includes an outer surface or skin 38. However, it should be understood that in other exemplary embodiments of the present disclosure, the aircraft 10 may additionally or alternatively include any other suitable configuration of stabilizers that may or may not extend directly along the vertical direction V or the horizontal / lateral direction L.

[0020] Figure 1 The exemplary aircraft 10 of FIG. 1 also includes a propulsion system having one or more aircraft engines. For example, the depicted embodiment includes a plurality of aircraft engines, each of which is configured to be mounted to the aircraft 10, such as to one of the pair of wings 20. More specifically, for the illustrated embodiment, the aircraft engines are configured as gas turbine engines, or more specifically, as turbofan jet engines 40, 42 that are attached to and suspended below the wings 20 in an underwing configuration. However, it should be understood that in other embodiments, the aircraft engines may be configured in any other suitable manner and may be mounted in any suitable location (e.g., on the fuselage at the tail end 18).

[0021] Still refer to Figure 1In an embodiment of the aircraft 10, the aircraft 10 also includes an electrical system 100. For the illustrated embodiment, the electrical system includes one or more generators 102 operable with the jet engines 40, 42. For example, one or both of the jet engines 40, 42 can be configured to provide mechanical power from a rotating shaft (e.g., an LP shaft or an HP shaft) to the generator 102. Although schematically depicted outside the respective jet engines 40, 42, in some embodiments, the generator 102 can be positioned inside the respective jet engines 40, 42. In addition, the generator 102 can be configured to convert the mechanical power into electrical power. For the illustrated embodiment, the electrical system 100 includes a generator 102 for each jet engine 40, 42, and also includes an energy storage device 104. The generator 102 can send electricity to the energy storage device 104, and the energy storage device 104 can store energy in the energy storage device 104.

[0022] Furthermore, it will be appreciated that electrical system 100 includes one or more electrical loads 106. One or more electrical loads 106 may be one or more aircraft loads (e.g., one or more control system loads, cabin loads, etc.), one or more propulsion system loads (e.g., one or more electric or hybrid electric propulsion systems), or both. In certain exemplary embodiments, the electrical power provided by generator 102 may be stored in energy storage device 104, may be sent to electrical loads 106, or both.

[0023] Notably, for the illustrated embodiment, the generator 102 , the energy storage device 104 , and the electrical load 106 are all connected to the electrical communication bus 108 such that the generator 102 can be in electrical communication with these components via the electrical communication bus 108 .

[0024] However, it should be understood that Figure 1 The illustrated aircraft 10 and electrical system 100 are provided by way of example only, and in other exemplary embodiments of the present disclosure, any other suitable aircraft 10 may be provided having an electrical system 100 configured in any other suitable manner.

[0025] Now refer to Figure 2, provides a schematic cross-sectional view of a propulsion engine according to an exemplary embodiment of the present disclosure. In certain exemplary embodiments, the propulsion engine may be configured as a high-bypass turbofan jet engine 200, referred to herein as "turbofan 200." Notably, in at least certain embodiments, the jet engines 40, 42 may also be configured as high-bypass turbofan jet engines. In various embodiments, turbofan 200 may represent the jet engines 40, 42. Alternatively, however, in other embodiments, the turbofan 200 may be incorporated into any other suitable aircraft 10.

[0026] like Figure 2 As shown, the turbofan 200 defines an axial direction A (extending parallel to a longitudinal centerline 201 for reference), a radial direction R, and a circumferential direction (extending about the axial direction A; not shown in FIG. Figure 2 Generally, turbofan 200 includes a fan section 202 and a turbine 204 disposed downstream of fan section 202 .

[0027] The exemplary turbine 204 shown generally includes a substantially tubular casing 206 defining an annular inlet 208. Casing 206 encloses, in series flow relationship, a compressor section comprising a boost compressor or low-pressure (LP) compressor 210 and a high-pressure (HP) compressor 212; a combustion section 214; a turbine section comprising a high-pressure (HP) turbine 216 and a low-pressure (LP) turbine 218; and an exhaust nozzle section 220. The compressor section, combustion section 214, and turbine section collectively define a core air flow path 221 extending from annular inlet 208 through LP compressor 210, HP compressor 212, combustion section 214, HP turbine section 216, LP turbine section 218, and exhaust nozzle section 220. A high-pressure (HP) shaft or spool 222 drivingly connects HP turbine 216 to HP compressor 212. A low-pressure (LP) shaft or spool 224 drivingly connects the LP turbine 218 to the LP compressor 210 .

[0028] For the illustrated embodiment, fan section 202 includes a variable-pitch fan 226 having a plurality of fan blades 228 coupled to a disk 230 in a spaced-apart manner. As shown, fan blades 228 generally extend outwardly from disk 230 in a radial direction R. Each fan blade 228 can rotate relative to disk 230 about a pitch axis P because fan blades 228 are operably coupled to suitable actuation members 232, which are configured to collectively change the pitch of fan blades 228 in unison. Fan blades 228, disk 230, and actuation members 232 can rotate together about longitudinal axis 12 via LP shaft 224.

[0029] Still refer to Figure 2 In the exemplary embodiment, disk 230 is covered by a rotatable forward hub 236 that is aerodynamically shaped to facilitate airflow through a plurality of fan blades 228. Additionally, exemplary fan section 202 includes an annular fan casing or outer nacelle 238 that circumferentially surrounds fan 226 and / or at least a portion of turbine 204. Nacelle 238 is supported relative to turbine 204 by a plurality of circumferentially spaced outlet guide vanes 240. A downstream section 242 of nacelle 238 extends over an outer portion of turbine 204 to define a bypass airflow passage 244 therebetween.

[0030] In addition, the depicted exemplary turbofan 200 includes a generator assembly 246 that can rotate with one or more rotatable components of the turbofan engine 200. Specifically, for the depicted embodiment, the generator assembly 246 can rotate with the high voltage / high speed system of the turbofan engine 200, and even more specifically, can rotate with the HP spool 222 via a drive train 248. In this manner, the generator assembly 246 can be configured to generate electrical power based on the rotation of the turbofan engine 200. Notably, the generator assembly 246 can be configured as part of the electrical system of the aircraft incorporating the generator assembly 246 and, as such, can be electrically coupled to an electrical bus (similar to the electrical system 100 of the aircraft 10, which has the generator 102 electrically coupled to the electrical bus 108).

[0031] However, it should be understood that Figure 2 The exemplary turbofan engine 200 shown is provided as an example only, and in other exemplary embodiments, the turbofan engine 200 may have any other suitable configuration. For example, in other exemplary embodiments, the turbofan engine 200 may be configured as a turboprop engine, a turbojet engine, a turbofan engine of a different configuration, or any other suitable gas turbine engine. Additionally, although the exemplary generator assembly 246 is Figure 2 206 of turbofan engine 200, but in other embodiments, it may be located in any other suitable location. Furthermore, for example, although generator assembly 246 is depicted as being rotatable with the thrust-producing engine, in other exemplary embodiments, generator assembly 246 may alternatively operate with a non-thrust-producing internal combustion engine, such as, for example, a dedicated turboshaft engine in an auxiliary power unit.

[0032] Now refer to Figure 3 , a generator assembly 300 according to an exemplary embodiment of the present disclosure is provided. Figure 3 The generator assembly 300 can be used in the same manner as above. Figure 2The exemplary generator assembly 246 described above is constructed in the same manner and may be incorporated into the Figure 1 The exemplary electrical system 100 of the aircraft 10 is depicted, or alternatively, may operate with any other suitable internal combustion engine and / or any other suitable electrical system of an aircraft.

[0033] As will be appreciated, Figure 3 The exemplary generator assembly 300 generally includes three machines. In particular, Figure 3 The exemplary generator assembly 300 includes a permanent magnet generator (PMG) 302, an exciter 304, and a main generator 306. The PMG 302 includes a PMG rotor 308 and a PMG stator 310, the exciter 304 includes an exciter rotor 312 and an exciter stator 314, and the main generator 306 includes a main generator rotor 316 and a main generator stator 318.

[0034] Now also refer to Figure 4 , the operation of the generator assembly 300 will be described in more detail. In particular, Figure 4 Provided Figure 3 Schematic diagram of an exemplary generator assembly 300.

[0035] Referring first to the PMG 302, the PMG rotor 308 may include one or more permanent magnets and may be rotated by the rotating components of the engine (see, e.g., Figure 2 ). For example, when Figure 2 When the exemplary generator assembly 246 is configured as shown, the PMG rotor 308 can rotate with the HP spool 222 of the turbofan engine 200. The rotation of the PMG rotor 308 relative to the PMG stator 310 can induce a voltage within the PMG stator 310. In particular, for the illustrated embodiment, the PMG stator 310 includes a PMG three-phase winding 320. Thus, the PMG stator 310 generates a three-phase AC voltage.

[0036] The exemplary generator assembly 300 is configured to provide power from the PMG stator 310 to the exciter stator 314. However, Figure 4 As can be appreciated from the schematic diagram of FIG, the generator assembly 300 is configured to condition the electrical power before providing such power to the exciter stator 314.

[0037] Specifically, for the illustrated embodiment, the generator assembly 300 includes a PMG rectifier 322. The PMG rectifier 322 converts the three-phase AC voltage from the PMG stator 310 into a DC voltage. Furthermore, for the illustrated embodiment, the generator assembly 300 includes a current modulator 324. The current modulator 324 is configured to modulate the flow of current from the PMG stator 310 to the exciter stator 314. In this manner, the current modulator 324 can affect (e.g., reduce) the amount of voltage applied to the terminals of the exciter stator 314 and, therefore, the amount of current flowing through the exciter stator 314. More specifically, for the exemplary embodiment illustrated, the current modulator 324 is configured as a half-H-bridge, which is configured to control the amount of voltage applied to the terminals of the exciter stator 314, thereby controlling the amount of current flowing through the exciter stator 314, by pulse-width modulation of two active switches. However, in other exemplary embodiments, the current modulator 324 may be configured in any other suitable manner, such as any other suitable voltage chopper configuration, such as a four-switch configuration, a single-switch configuration, any other suitable pulse width modulation arrangement, etc. The operation and control of the current modulator 324 will be described in more detail below.

[0038] The controlled DC voltage supplied to the exciter stator 314 can generate a rotating field relative to the exciter rotor 312 and can also induce a voltage in the three-phase windings 326 of the exciter rotor 312. The exciter rotor 312 is configured to provide power to the main generator rotor 316 of the main generator 306. As with the transmission of power from the PMG stator 310 to the exciter stator 314, the generator assembly 300 also includes features for conditioning the power supplied from the exciter rotor 312 to the main generator rotor 316. Specifically, for the illustrated embodiment, the generator assembly 300 includes an exciter rectifier 328 for receiving the three-phase AC voltage from the exciter rotor 312 and converting the power to a DC voltage. It will be appreciated that for the illustrated embodiment, the exciter rectifier 328 is configured to rotate with the exciter rotor 312, such that the exciter rectifier 328 can be referred to as a rotating rectifier.

[0039] Still refer to Figure 4, a DC voltage from an exciter rectifier 328 is applied to a main generator rotor 316 of a main generator 306. Rotation of the main generator rotor 316 relative to the main generator stator 318 can generate electrical power. Specifically, for the illustrated embodiment, the main generator stator 318 includes a first three-phase winding 330 and a second three-phase winding 332. Both the first three-phase winding 330 and the second three-phase winding 332 are configured to have a voltage induced therein by the main generator rotor 316. However, it will be appreciated that a phase shift 334 greater than zero degrees and less than 90 degrees is defined between the first three-phase winding 330 and the second three-phase winding 332. More specifically, for the illustrated embodiment, a phase shift 334 between the first three-phase winding 330 and the second three-phase winding 332 is defined between the first three-phase winding 330 and the second three-phase winding 332, for example, equal to approximately 30 degrees, and more specifically, equal to 30 degrees. As will be described in more detail below, this configuration can reduce harmonics within the electrical output of the generator assembly 300.

[0040] Briefly, it will be understood that in Figure 4 The phase shift 334 is depicted schematically and not to scale in FIG. As used herein, the term "phase shift" refers to the circumferential position of one winding relative to another winding within the stator of an electric machine.

[0041] Still refer to Figure 4 , each of the first three-phase winding 330 and the second three-phase winding 332 is configured to generate a corresponding three-phase AC voltage. Thus, the main generator 306 further includes a first main generator rectifier 336 downstream of the first three-phase winding 330 for converting the three-phase AC voltage from the first three-phase winding 330 into a DC voltage. Similarly, the main generator 306 further includes a second main generator rectifier 338 downstream of the second three-phase winding 332 for converting the three-phase AC voltage from the second three-phase winding 332 into a DC voltage.

[0042] Furthermore, the generator assembly 300 includes a main generator interphase transformer 340. The main generator interphase transformer 340 is electrically coupled to the first main generator rectifier 336 and the second main generator rectifier 338 at a location downstream of both the first main generator rectifier 336 and the second main generator rectifier 338. It should be understood that, for the illustrated embodiment, the main generator interphase transformer 340 of the generator assembly 300 is a single interphase transformer. More specifically, the interphase transformer 340 includes two branches, each branch coupled to one of the first main generator rectifier 336 and the second main generator rectifier 338 at a location downstream of both the first main generator rectifier 336 and the second main generator rectifier 338.

[0043] As will be appreciated, it is desirable that each of the first three-phase winding 330 and the second three-phase winding 332 be capable of operating with a full 120 degrees of conduction in each phase, effectively operating as two independent devices operating in parallel. The interphase transformer 340 prevents current from switching between the first three-phase winding 330 path and the second three-phase winding 332 path, so that neither has to carry twice the current load in half the time. As will be appreciated, this reduces losses in the system and improves efficiency. In short, the inclusion of a single interphase transformer 340 can limit the circulation of current through the mutual impedance between the two branches of the interphase transformer 340.

[0044] However, it will be appreciated that in other exemplary embodiments, generator assembly 300 may include any other suitable number and / or configuration of interphase transformers.

[0045] In addition, still refer to Figure 4 , generator assembly 300 also includes a DC voltage output. More specifically, generator assembly 300 includes a positive DC voltage output 342 and a negative DC voltage output 344. To ensure that generator assembly 300 provides the desired amount and level of power, generator assembly 300 also includes a DC current sensor 346 and a voltage clamp 348. DC current sensor 346 is in electrical communication with the DC voltage outputs, particularly positive DC voltage output 342, and voltage clamp 348 is in electrical communication with the DC voltage outputs, particularly positive DC voltage output 342 and negative DC voltage output 344. In certain exemplary embodiments, voltage clamp 348 can be configured as an active clamp having a transistor arranged in series with a resistor, the transistor having a gate controlled based on, for example, DC current sensor 346, to control the output voltage of generator assembly 300.

[0046] Furthermore, as described above, the generator assembly 300 includes a power output control 350. The power output control 350 is configured to influence the amount of voltage induced in the first three-phase winding 330 and the second three-phase winding 332 of the main generator stator 318 of the main generator 306. For the illustrated embodiment, the power output control 350 includes a DC current sensor 346 operable with the DC power output and a controller 352. The DC current sensor 346 can provide data indicative of the current of the power provided by the main generator 306 to the controller 352. The power output control 350 also includes a voltage sensor 349 for sensing data indicative of the voltage of the power provided by the main generator 306 and providing such data to the controller 352. The controller 352 can use a series of control schemes compared to a reference value 354 to determine whether any correction is required. Specifically, for the illustrated embodiment, the power output control 350 is operably coupled to the current modulator 324 located between the PMG stator 310 and the exciter stator 314. In this manner, power output control 350 may control the power output from primary generator 306 relative to reference value 354 using current modulator 324 .

[0047] More specifically, for the illustrated embodiment, the controller 352 of the power output control 350 can utilize a series of proportional-integral controls 356. Each proportional-integral control 356 can generally include a summing block 357 that sums an input value (e.g., a reference value 354 or feedforward value) with sensed data (e.g., from a DC current sensor 346 or voltage sensor 349 located downstream of the first and second main generator rectifiers 336; from a current / voltage sensor 358 located downstream of the first and second three-phase windings 330 and 332 and upstream of the first and second main generator rectifiers 336; etc.). The summing block 357 can then provide a reference value forward. This reference value can be provided to a subsequent summary block or converted into a "gating" value 360 ​​that is provided to the current modulator 324.

[0048] Specifically, for the illustrated embodiment, the power output control 350 includes a first proportional-integral control 356A, a second proportional-integral control 356B, and a third proportional-integral control 356C. The first proportional-integral control 356A includes a summing block 357 that sums the reference value 354 with data from the voltage sensor 349. The second proportional-integral control 356B receives the value from the summing block 357 of the first proportional-integral control 356A and a feedforward value from the DC current sensor 346, the voltage sensor 349, or both at block 362. This value is provided to the summing block 357 of the second proportional-integral control 356B, which is combined with data from the AC voltage sensor 358. The third proportional-integral control 356C receives the value from the summing block 357 of the second proportional-integral control 356B and feedforward data from the DC current sensor 346, the voltage sensor 349, or both at block 364 (as may be modified by a "gain" block 365). This value is provided to summing block 357 of third proportional-integral control 356C, which is combined with data from the current sensor within current modulator 324, which is used to sense data indicative of current going to or flowing through exciter stator 314. The resulting value is provided to block 366, which is combined with feedforward data from DC current sensor 346, voltage sensor 349, or both (as may be modified by second "gain" block 367), and provided as "gate" value 360 ​​to block 360.

[0049] It will be understood that the output control 350 can be executed by one or more microprocessors or any other suitable computing device. Furthermore, it will be appreciated that the output control 350 is provided by way of example only, and in other exemplary embodiments, other suitable output controls 350 / controllers 352 may be provided. For example, in certain exempted embodiments, the controller 352 may further receive data from various other voltage and / or current sensors for sensing data indicative of voltage and current at other locations within the generator assembly 300.

[0050] For the illustrated embodiment, generator assembly 300 is configured to provide a high voltage (e.g., a voltage greater than 120 volts) DC power output. Specifically, for the illustrated embodiment, generator assembly 300 is configured to provide a voltage greater than or equal to approximately 270 volts DC power output. It will be appreciated that this is a relatively high power output for a generator assembly 300 for an aircraft electrical system. However, by utilizing such a high power output, the weight of the electrical bus that carries this power can be reduced because less current is required for a given amount of power to the electrical loads.

[0051] Furthermore, it will be appreciated that utilizing parallel three-phase windings 330, 332 within the main generator stator 318 of the main generator 306, with a phase shift 334 defined in the manner described above, can further allow for a reduction in the weight of the electric motor. More specifically, the phase shift 334 of the first three-phase winding 330 and the second three-phase winding 332 of the main generator stator 318 can reduce harmonics within the output power of the generator assembly 300, making it less necessary to correct / account for such ripple on heavy equipment (e.g., capacitors).

[0052] Therefore, the generator assembly 300 of the present disclosure may reduce the weight and improve the efficiency of an electrical system including the generator assembly 300 .

[0053] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. If such other examples include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims, then these other examples are intended to be included within the scope of the claims.

[0054] Further aspects of the invention are provided by the subject matter of the following clauses:

[0055] A generator assembly for an aircraft includes a main generator, the main generator including a main rotor and a main stator, the main stator including a first three-phase winding and a second three-phase winding, the first three-phase winding and the second three-phase winding each configured to have a voltage induced therein by the main rotor, the first three-phase winding and the second three-phase winding defining a phase shift greater than zero degrees therebetween.

[0056] The generator assembly of one or more of the preceding clauses, wherein the phase shift is approximately 30 degrees.

[0057] The generator assembly according to one or more of the above clauses, wherein the first three-phase winding and the second three-phase winding are arranged in parallel.

[0058] The generator assembly according to one or more of the above clauses, wherein the main generator further comprises a first main generator rectifier downstream of the first three-phase winding and a second main generator rectifier downstream of the second three-phase winding.

[0059] The generator assembly according to one or more of the preceding clauses, wherein the first main generator rectifier and the second main generator rectifier are electrically coupled to a main generator interphase transformer.

[0060] The generator assembly according to one or more of the above clauses, further comprising an exciter comprising an exciter rotor and an exciter stator, wherein the exciter rotor applies an exciter voltage to the main rotor of the main generator through a rotating rectifier.

[0061] The generator assembly according to one or more of the preceding clauses, wherein the exciter voltage is a DC exciter voltage, and wherein the exciter further comprises an exciter rectifier for converting a three-phase AC exciter voltage into the DC exciter voltage.

[0062] The generator assembly according to one or more of the above clauses, further comprising: a permanent magnet generator (PMG) comprising a PMG rotor and a PMG stator, wherein the PMG stator provides a PMG voltage to the exciter stator.

[0063] The generator assembly according to one or more of the above clauses, further comprising: a current modulator for reducing the PMG current provided to the exciter stator.

[0064] The generator assembly of one or more of the above clauses, wherein the generator assembly comprises a power output control, wherein the power output control is operatively coupled to the current modulator.

[0065] The generator assembly of one or more of the above clauses, wherein the main generator includes a DC power output, and wherein the generator assembly includes a power output control configured to affect an amount of voltage induced in the first three-phase winding and the second three-phase winding, wherein the power output control includes a DC current sensor operable with the DC power output.

[0066] The generator assembly of one or more of the preceding clauses, wherein the main generator comprises a positive DC power output and a negative DC power output, and wherein the main generator further comprises a voltage clamp electrically coupled between the positive DC power output and the negative DC power output.

[0067] The generator assembly of one or more of the preceding clauses, wherein the main generator provides a high power DC electrical output.

[0068] An aircraft electrical system comprises: an internal combustion engine; and a generator assembly, the generator assembly including a main generator, the main generator including a main rotor and a main stator, the main generator rotor being driven directly or indirectly by the internal combustion engine, the main stator including a first three-phase winding and a second three-phase winding, the first three-phase winding and the second three-phase winding being each configured to have a voltage induced therein by the main rotor, a phase shift greater than zero degrees being defined between the first three-phase winding and the second three-phase winding.

[0069] The aircraft electrical system of one or more of the preceding clauses, wherein the phase shift is approximately 30 degrees.

[0070] The aircraft electrical system according to one or more of the above clauses, wherein the first three-phase winding and the second three-phase winding are arranged in parallel.

[0071] The aircraft electrical system according to one or more of the above clauses, wherein the main generator further comprises a first main generator rectifier downstream of the first three-phase winding and a second main generator rectifier downstream of the second three-phase winding.

[0072] The aircraft electrical system according to one or more of the above clauses, wherein the first main generator rectifier and the second main generator rectifier are electrically coupled to a main generator interphase transformer.

[0073] The aircraft electrical system of one or more of the preceding clauses, wherein the main generator provides a DC power output of approximately 270 volts.

[0074] The aircraft electrical system of one or more of the above clauses, wherein the main generator includes a positive DC power output and a negative DC power output, wherein the aircraft electrical system further includes an electrical bus, and wherein the positive DC power output and the negative DC power output provide power to the electrical bus of the aircraft electrical system.

Claims

1. A generator assembly for an aircraft, characterized in that: include: a main generator, the main generator comprising a main rotor and a main stator, the main stator comprising a first three-phase winding and a second three-phase winding, the first three-phase winding and the second three-phase winding being arranged in parallel, having independent neutral points, and each being configured to have a voltage induced therein by the main rotor, a phase shift being defined between the first three-phase winding and the second three-phase winding, The main generator further includes a first main generator rectifier and a second main generator rectifier, the first main generator rectifier is configured to convert the three-phase AC voltage from the first three-phase winding into a DC voltage, the second main generator rectifier is configured to convert the three-phase AC voltage from the second three-phase winding into a DC voltage, the first main generator rectifier and the second main generator rectifier each having a first terminal and a second terminal, The main generator further includes a single main generator interphase transformer having a first branch electrically coupled to a first terminal of the first main generator rectifier and a second branch electrically coupled to a first terminal of the second main generator rectifier, a second terminal of the first main generator rectifier and a second terminal of the second main generator rectifier not electrically coupled to the interphase transformer, and The first three-phase winding and the second three-phase winding are connected in parallel through the single main generator interphase transformer.

2. The generator assembly according to claim 1, characterized in that: The phase shift is approximately 30 degrees.

3. The generator assembly according to claim 1, characterized in that: Wherein the first three-phase winding and the second three-phase winding are each configured to operate with a full 120 degree conduction in each phase.

4. The generator assembly according to claim 1, characterized in that: The phase shift is approximately 20 degrees.

5. The generator assembly according to claim 1, characterized in that: wherein the first branch and the second branch of the single main generator interphase transformer are both electrically coupled to a first DC voltage output, and wherein the second terminal of the first main generator rectifier and the second terminal of the second main generator rectifier are directly electrically coupled to a second DC voltage output without an interphase transformer being positioned therebetween.

6. The generator assembly according to claim 1, characterized in that: Further including: An exciter includes an exciter rotor and an exciter stator, wherein the exciter rotor applies an exciter voltage to the main rotor of the main generator through a rotating rectifier.

7. The generator assembly according to claim 6, characterized in that: Wherein the exciter voltage is a DC exciter voltage, and wherein the exciter further comprises an exciter rectifier for converting the three-phase AC exciter voltage into a DC exciter voltage.

8. The generator assembly according to claim 6, characterized in that: Further including: A permanent magnet generator - PMG, the permanent magnet generator includes a PMG rotor and a PMG stator, wherein the PMG stator provides a PMG voltage to the exciter stator.

9. The generator assembly according to claim 8, characterized in that: Further including: A current modulator is provided for reducing the PMG current supplied to the exciter stator.

10. The generator assembly according to claim 9, characterized in that Wherein the generator assembly includes a power output control, wherein the power output control is operably coupled to the current modulator.

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