Transverse flux asynchronous motor
By designing a motor structure with multiple stationary windings and multiple flux paths, the problems of high maintenance costs and low efficiency of existing aircraft generators are solved, and higher power density, efficiency and reliability are achieved.
Patent Information
- Application Number
- CN202410933858.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-18
- Filing Date
- 2024-07-12
- Publication Date
- 2025-02-21
AI Technical Summary
Existing aircraft generators have problems of high maintenance costs, short service life, system complexity and low efficiency, especially in the applications of constant speed, variable speed, and independent speed variable frequency generators.
A motor structure is designed, including a stator, a first stationary winding, a second stationary winding and a rotor, the second stationary winding has a plurality of winding segments, the rotor passes through the stator and the second stationary winding, and there are multiple magnetic pole lobes on the rotor segment. , the magnetic pole lobe is located on opposite sides of the second stationary winding. By adjusting the AC excitation current, multiple flux paths are generated, allowing the motor to achieve independent speed and variable frequency power generation.
Higher power density, efficiency, reliability and lower complexity are achieved, reducing the cost, weight and maintenance requirements of aircraft power generation systems, while improving the efficiency and reliability of the system.
Smart Images
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Abstract
Description
Technical Field
[0001] The present disclosure relates generally to the field of electric machines, and more particularly to generators and motors. Background Art
[0002] Electric machines, such as generators or alternators, generate electricity for a variety of applications. In aircraft applications, such electric machines are responsible for generating electricity to meet the power needs of the aircraft. More specifically, such electric machines are configured to generate alternating current (AC) power for various onboard systems and equipment, such as avionics, lighting systems, environmental control systems (ECS), galley equipment, entertainment systems, and other electrical equipment.
[0003] Conventional AC motors used in aircraft have various disadvantages. In one example, conventional constant speed constant frequency (CSCF) generators used in aircraft require a constant speed drive (CSD) to couple the CSCF generator to the aircraft's engine. The CSD is a complex and bulky mechanical system with relatively high maintenance costs and a relatively short service life.
[0004] In another example, a conventional variable speed, variable frequency (VSVF) generator may be coupled to an engine of an aircraft without a CSD. However, a conventional VSVF generator generates AC power with a wide range of frequencies that depend on the engine speed. This dependency requires a separate conversion device, such as a full power AC / DC / AC converter, for the conventional VSVF generator to maintain the output frequency at a desired level for a particular application. The result is that the system becomes more complex and has an adverse effect on system efficiency and reliability.
[0005] In another example, a conventional independent variable speed, variable frequency (ISVF) generator may also be coupled to an engine of an aircraft without a CSD. Conventional ISVF generators are capable of generating AC power with a constant frequency at different engine speeds. However, conventional ISVF generators typically include power electronic components (e.g., rectifiers, inverters) coupled to a rotor that rotates during operation of the conventional ISVF generator. The rotation of these power electronic components can cause reliability issues. In addition, conventional ISVF generators require wireless control of these power electronic devices because their rotation increases the complexity and cost of conventional ISVF generators. Summary of the invention
[0006] An example related to a motor is disclosed, which can achieve independent speed, variable frequency power generation, with higher power density, efficiency, reliability and lower complexity than conventional methods. In a disclosed example, the motor includes a stator, a first stationary winding coupled to the stator, a second stationary winding coupled to the stator and a rotor. The second stationary winding includes a plurality of winding segments corresponding to the number of phases of the motor power. The rotor extends through the stator and the second stationary winding. The rotor includes a plurality of rotor segments. Each rotor segment of the plurality of rotor segments includes a plurality of magnetic pole lobes extending radially from the rotor segment. Two or more magnetic pole lobes of each rotor segment are located on opposing sides of the corresponding winding segment of the second stationary winding.
[0007] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 An example embodiment of an aircraft including an electric machine of the present disclosure is schematically shown.
[0009] Figure 2 Shows Figure 1 A cross-sectional view of the motor.
[0010] Figure 3 shows the direction of the magnetic flux path generated by the motor Figure 1 A cross-sectional view of the motor.
[0011] Figure 4-5 Shows a prominent Figure 1 Different views of different aspects of the rotor of an electric machine.
[0012] Figure 6-8 Shows Figure 1 Figure 2 is a graph of different example waveforms generated during a simulated run of a motor. DETAILED DESCRIPTION
[0013] Conventional AC motors used in aircraft have various disadvantages. In one example, a conventional constant speed constant frequency (CSCF) generator used in an aircraft produces an output frequency that depends on the rotor speed of the conventional CSCF generator. Conventional CSCF generators require a constant speed drive (CSD) to couple the rotor to the aircraft's engine. The CSD converts the variable engine speed to a constant rotor speed. The CSD is a complex and cumbersome mechanical system that has a relatively high maintenance cost and a relatively short service life.
[0014] In another example, a conventional variable speed, variable frequency (VSVF) generator can produce a variable output frequency and voltage by adjusting the rotational speed of the generator. A conventional VSVF generator can be coupled to an aircraft engine without a CSD. However, a conventional VSVF generator requires a separate conversion device, such as a full power AC / DC / AC converter, to maintain the output frequency at a desired level for a particular application. As a result, the overall system becomes more complex and has an adverse effect on the efficiency and reliability of the system.
[0015] In another example, a conventional independent speed, variable frequency (ISVF) generator produces a variable frequency output while operating at a speed independent of the output frequency, allowing the speed and frequency generated to be decoupled. Conventional ISVF generators can also be coupled to an aircraft engine without a CSD. However, conventional ISVF generators typically include power electronic components (e.g., rectifiers, inverters) that are coupled to a rotor that rotates during operation of the conventional ISVF generator. The rotation of these power electronic components can cause reliability issues. In addition, conventional ISVF generators require wireless control of these power electronic devices because their rotation increases the complexity and cost of conventional ISVF generators.
[0016] Therefore, the present description is directed to an electric machine whose structure allows the electric machine to achieve ISVF power generation while also having higher power density, efficiency, reliability and lower complexity relative to conventional electric machines. In one example, the electric machine includes a stator, a first stationary winding coupled to the stator, a second stationary winding coupled to the stator and a rotor. The second stationary winding includes a plurality of winding segments corresponding to the number of phases of the motor power. The rotor extends through the stator and the second stationary winding. The rotor includes a plurality of rotor segments. Each rotor segment of the plurality of rotor segments includes a plurality of magnetic pole lobes extending radially from the rotor segment. Two or more magnetic pole lobes of each rotor segment are located on opposite sides of the corresponding winding segment of the second stationary winding.
[0017] The structure of the motor can generate multiple flux paths according to the AC excitation current applied to one of the stationary windings. Each flux path extends transversely through the rotor in three dimensions in the radial direction and the axial direction relative to the motor. More specifically, each flux path passes through a pair of pole lobes of the same rotor segment of the rotor, which are located on opposite sides of the corresponding winding segment of the second stationary winding. When the rotor speed changes, by adjusting the AC excitation current, the flux paths collectively enable the motor to generate electricity at a desired output frequency. In this way, the output frequency is decoupled from the rotor speed, which is also called independent speed, variable frequency.
[0018] Furthermore, achieving independent speed, variable frequency in this manner allows the motor's rotor to be directly connected to the aircraft's engine shaft without the need for a CSD, thereby improving the reliability, power density and efficiency of the aircraft's power generation system while also reducing the cost, weight and complexity of the aircraft's power generation system relative to conventional motors that require a CSD.
[0019] Furthermore, since the first winding and the second winding are stationary in the motor, the likelihood of winding degradation during motor operation is reduced relative to conventional motors that include rotating electronic components located on the rotor. This increases the reliability of the motor relative to conventional motors that include rotating electronic components located on the rotor. Furthermore, since the first winding and the second winding are stationary in the motor, the electrical connections of these windings are less complex relative to the electrical connections (e.g., brushes) of conventional motors that include rotating electronic components located on the rotor.
[0020] Figure 1 An example embodiment of an aircraft 100 including an electric machine 102 of the present disclosure is schematically shown. The aircraft 100 includes an engine nacelle 104. Note that for purposes of discussion, Figure 1 A hypothetical cutout 106 is depicted, schematically illustrating relevant components within the nacelle 104. The cutout 106 does not exist in the actual nacelle 104.
[0021] The aircraft 100 includes an engine 108 within the nacelle 104. In one example, the engine 108 is a gas turbine / jet engine configured to provide power to propel the aircraft 100. More specifically, a jet engine works by compressing incoming air, mixing it with fuel, combusting the mixture, and then expanding and accelerating the exhaust to create thrust to overcome drag and propel the aircraft 100 through the air during flight. In other embodiments, the engine 108 may take another form, such as a piston engine or a turboprop engine. Depending on the type of aircraft, the engine 108 may take any suitable form.
[0022] The auxiliary shaft 110 is driven by the engine 108 and provides mechanical power for driving various accessories and systems of the aircraft 100. The auxiliary shaft 110 is coupled to the motor 102. More specifically, the auxiliary shaft 110 is coupled to the rotor 206 (e.g., Figure 2 206 ), so that rotation of the auxiliary shaft 110 causes rotation of the rotor 206 . The speed of the auxiliary shaft 110 varies with the speed of the engine 108 .
[0023] The electric machine 102 is configured to convert the mechanical power generated by the rotation of the auxiliary shaft 110 into alternating current (AC) power, whose output frequency is independent of the rotational speed of the auxiliary shaft 110. In other words, the electric machine 102 operates as an ISVF generator, which allows the rotational speed and the output frequency of the generated AC power to be decoupled. Note that the independent speed, variable frequency operation of the electric machine 102 allows the rotor 206 to be directly coupled to the auxiliary shaft 110 without the use of a CSD.
[0024] The motor 102 includes a controller 112 configured to apply an AC excitation current to a stationary winding of the motor 102 according to the speed of the rotor 206 to adjust the output frequency of the AC output power generated by the motor 102 to a desired output frequency that is independent of the rotational speed of the rotor 206. More specifically, the controller 112 can control the output frequency of the AC output power by adjusting the frequency of the AC excitation current. The controller 112 can be configured to adjust the frequency of the AC excitation current based on the speed of the rotor 206 to generate any suitable output frequency of the AC output power. Typically, the desired output frequency is a constant frequency, although in some examples, the controller 112 can change the output frequency under some conditions. In addition, the controller 112 is configured to adjust the magnitude of the AC excitation current to control the output voltage and the power generated by the motor 102 and delivered to the system load. The controller 112 can be configured to adjust the magnitude of the AC excitation current to generate any suitable output voltage and power to meet any suitable system load.
[0025] The electric machines 102 are configured to output AC output power to an AC electrical bus 114. The AC electrical bus 114 is configured to provide AC power to various AC loads and systems on the aircraft 100. These may include avionics, lighting systems, environmental control systems (ECS), galley equipment, entertainment systems, and other electrical equipment.
[0026] In the illustrated embodiment, the motor 102 is configured as an ISVF generator that provides AC power to various AC loads and systems in an aircraft. In other embodiments, the motor 102 may be configured to generate AC power in other types of vehicles (e.g., automobiles, spacecraft, ships, submersible vehicles, etc.). In other embodiments, the motor 102 may be used in stationary applications. In some embodiments, the motor 102 may be configured to provide AC power to a propulsion engine of an aircraft or another type of vehicle. In such embodiments, the motor is configured to operate as an electric motor.
[0027] Figure 2 Shows Figure 11 is a cross-sectional view of an electric machine 102 schematically depicting relevant components. In the illustrated embodiment, the electric machine 102 is configured to generate three-phase AC power and includes various features to support the generation of three different AC powers present in such three-phase AC power. Note that in other embodiments, the electric machine 102 may be configured to generate AC power with a different number of phases (e.g., single phase, six phases, etc.), and the electric machine may include various features to support the generation of AC power corresponding to the number of phases.
[0028] The motor 102 includes a stator 200, a first stationary winding 202, a second stationary winding 204, and a rotor 206. The stator 200 is configured to provide mechanical support and stability to the motor 102, and more specifically, maintain its position relative to the rotor 206. The stator 200 is configured to accommodate the first stationary winding 202. In the illustrated embodiment, the stator 200 includes a plurality of laminated cores 210. A plurality of slots 212 are formed in the plurality of laminated cores 210 of the stator 200.
[0029] The first stationary winding 202 includes a plurality of winding conductors 214 arranged in a specific pattern (e.g., a three-phase configuration) in the stator 200 to generate a magnetic field when energized with alternating current. More specifically, the winding conductors 214 of the first stationary winding 202 are arranged in a plurality of slots 212 formed in the stator 200 and are wound around a plurality of laminated cores 210.
[0030] The stator 200 forms a cylindrical cavity 216, and the second stationary winding 204 is coupled within the cylindrical cavity 216. In one example, the second stationary winding 204 is mounted along the inner diameter of the stator 200 along the cylindrical cavity 216. The second stationary winding 204 includes a plurality of winding segments 218 corresponding to the number of phases of the power of the motor 102. In the illustrated embodiment, the second stationary winding 204 includes three winding segments 218.1, 218.2, and 218.3 corresponding to the three-phase AC power generated by the motor 102. The second stationary winding 204 may include any suitable number of segments for generating any suitable number of AC power phases. The winding segments 218 are distributed axially along the cylindrical cavity 216. Note that the winding segments 218 are stationary within the cylindrical cavity 216 and do not move with the rotor 206.
[0031] The rotor 206 extends axially through the cylindrical cavity 216 within the stator 200. The rotor 206 includes a plurality of rotor segments 220 corresponding to the number of phases of the AC power generated by the motor 102. In the illustrated embodiment, the rotor 206 includes three rotor segments 220.1, 220.2, and 220.3, and corresponds to the three-phase AC power generated by the motor 102. The rotor 206 may include any suitable number of rotor segments for generating any suitable number of AC power phases. The rotor segments 220 are axially distributed along the cylindrical cavity 216. In addition, the rotor 206 extends through the second stationary winding 204. In particular, each of the plurality of winding segments 218 includes a central hole through which the corresponding rotor segment 220 extends, so that each rotor segment 220 is arranged on opposite sides of the corresponding winding segment 218.
[0032] Each rotor segment 220 includes a plurality of pole lobes 222 extending radially from the rotor segment 220. More specifically, each rotor segment 220 has two groups of pole lobes arranged on opposite sides of the corresponding winding segment 218. In other words, each rotor segment 220 has two parts, one on each side of the corresponding winding segment 218. The pole lobes in the first group on one side of the rotor segment 220 are indicated by ('). The pole lobes in the second group on the other side of the rotor segment 220 are indicated by ("). For example, rotor segment 220.1 includes a first group of pole lobes 222.1.1', 222.1.2' and 222.1.3', and a second group of pole lobes 222.1.1", 222.1.2" and 222.1.3". The first set of pole lobes 222' and the second set of pole lobes 222" are arranged on opposite sides of the winding segment 218.1. Each rotor segment 220 in the rotor 206 may include two or more pole lobes 222 located on opposite sides of the corresponding winding segment 218 of the second stationary winding 204. The number of pole lobes 222 on opposite sides of the corresponding winding segment 218 depends on the number of phases of the power generated by the motor 102.
[0033] As mentioned above, reference Figure 1 , the controller 112 is configured to adjust the AC excitation current according to the speed of the rotor 206 to produce the desired output frequency. Depending on the embodiment, the controller 112 can be configured to apply the AC excitation current to either the first stationary winding 202 or the second stationary winding 204. The AC output power is generated on the other stationary winding. In the illustrated embodiment, the controller 112 applies the AC excitation current to the second stationary winding 204, and the AC output power is generated on the first stationary winding 202.
[0034] When the second stationary winding 204 is energized by an AC field current, a magnetic field is generated. Figure 3An example flux path 300 of a magnetic field generated by the motor 102 is shown. The flux path 300 begins at an origin 302 at the center of the first rotor segment 220.1 of the rotor 206. The flux path 300 extends radially laterally through the first rotor segment 220.1 along the pole salient 222.1.3' toward the first stationary winding 202. The flux path 300 continues to travel radially along the first stationary winding 202 and the stator 200. The flux path 300 then passes axially through the first winding segment 218.1 of the second stationary winding 204 to the opposite side of the first rotor segment 220.1. The flux path 300 extends laterally through the first rotor segment 220.1 and radially along the pole lobes 222.1.3" back to the center of the first rotor segment 220.1. Finally, the flux path returns axially through the first winding segment 218.1 and through the first rotor segment 220.1 back to the origin 302 to complete the flux path 300. The flux path 300 travels three-dimensionally through the electric machine 102 in radial and axial directions.
[0035] The magnetic flux path 300 passes through a pair of magnetic pole lobes 222.1.3' and 222.1.3" on opposite sides of the first winding segment 218.1. The motor 102 generates similar magnetic flux paths through each pair of opposing magnetic pole lobes on each of the plurality of rotor segments 220. For example, a second magnetic flux path (not shown) passes through a pair of magnetic pole lobes 222.1.1' and 222.1.1". Similarly, a third magnetic flux path (not shown) passes through a pair of magnetic pole lobes 222.1.2' and 222.1.2" (e.g. Figure 4 ). The flow of AC excitation current constantly changes direction in a cyclical manner to produce a waveform that alternates between positive and negative half-cycles as the current changes direction. This periodic change in direction causes the poles of the pole lobes 222' and 222" to flip back and forth. In the illustrated example, at this time, the pole lobes 222.1', 222.2' and 222.3' are north poles, and the pole lobes 222.1.1", 222.1.2" and 222.1.3" are south poles. As the flow of AC excitation current changes direction, the poles switch so that the pole lobes 222.1.1', 222.1.2' and 222.3' are south poles, and the pole lobes 222.1.1", 222.1.2" and 222.1.3" are north poles, until the AC excitation current changes direction again, and so on, according to the period of the waveform. Similarly, a triple flux path is generated for each of the other rotor segments 220 of the motor 102.
[0036] When the rotor 206 rotates within the stator 200 of the motor 102, the interaction between the rotor 206 and the first stationary winding 202 and the second stationary winding 204 generates a plurality of magnetic flux paths. Based on the AC excitation current applied to the second stationary winding 204 through the electromagnetic induction process, the plurality of magnetic flux paths collectively generate a three-phase AC output power of a desired frequency on the first stationary winding 202. The three-phase AC output power having the desired frequency is output from the first stationary winding 202 to the AC bus 114 (e.g., Figure 1 ) or another suitable load of the aircraft 100 (such as Figure 1 shown).
[0037] The relationship between the rotor speed and the frequency between the first winding and the second winding is as follows:
[0038] f1=f re +f2
[0039]
[0040] f1: frequency of the first stationary winding
[0041] f2: frequency of the secondary stationary winding
[0042] f re : The electrical frequency of the rotor
[0043] p: number of poles of the motor
[0044] n: rotor speed (rpm)
[0045] Using the above equation, if f1 is selected as the desired frequency, f2 can be adjusted as the rotor speed changes to maintain a constant frequency output at the desired frequency.
[0046] The arrangement of the pole lobe sets 222 ′ and 222 ″ on different rotor segments 220 allows the three-phase AC excitation current to provide a constant torque output during operation of the motor 102 . Figure 4-5 Different views are shown highlighting different aspects of the rotor 206 of the electric machine 102 . Figure 4 An oblique front view of the rotor 206 is shown, with the second stationary winding 204 omitted for clarity. Figure 5 A top view of the rotor 206 divided into a plurality of rotor segments 220.1, 220.2 and 220.3 is shown. The arrangement of the winding segments 218.1, 218.2 and 218.3 of the second stationary winding 204 is shown in dashed lines on the plurality of rotor segments 220.1, 220.2 and 220.3.
[0047] The arrangement of the pole lobes on different rotor segments of the rotor 206 is based on the number of phases of the AC output power generated by the motor 102. More specifically, different groups of pole lobes 222 on the same rotor segment 220 are offset by a plurality of electrical angles. Furthermore, different groups of pole lobes 222 on different rotor segments 220 are offset by several degrees of electrical angle. The equation relating electrical angle to mechanical angle is as follows:
[0048]
[0049] θ e : The electrical angle of the rotor
[0050] θ m : Mechanical angle of the rotor
[0051] P: Number of magnetic pole lobes of the motor
[0052] In the illustrated embodiment, the arrangement of the pole lobes 222 on different rotor segments 222 is configured to generate three-phase power. Thus, the rotor 206 includes three rotor segments 220.1, 220.2 and 220.3. Each rotor segment includes two groups of pole lobes 222' and 222". Each group of pole lobes 222 includes three pole lobes in each group. Specifically, the first rotor segment 220.1 includes a first group of pole lobes 222.1.1', 222.1.2' and 222.1.3', each of which is offset by 120 electrical degrees relative to each other. The first rotor segment 220.1 also includes a second group of pole lobes 222.1.1", 222.1.2" and 222.1.3", each of which is offset by 120 electrical degrees relative to each other. Furthermore, the first set of pole lobes 222.1.1', 222.1.2' and 222.1.3' are rotated 180 electrical degrees relative to the second set of pole lobes 222.1.1', 222.1.2' and 222.1.3' on the first rotor segment 220.1. Such an arrangement aligns each pole lobe in one set with the gap between the pole lobes of the opposite set on the rotor segment.
[0053] The second rotor segment 220.2 includes a first set of pole lobes 222.2.1', 222.2.2' and 222.2.3', each of which is offset by 120 electrical degrees relative to each other. The second rotor segment 220.2 further includes a second set of pole lobes 222.2.1", 222.2.2", and 222.2.3", each of which is offset by 120 electrical degrees relative to each other. In addition, the first set of pole lobes 222.2.1', 222.2.2' and 222.2.3' are rotated 180 electrical degrees relative to the second set of pole lobes 222.2.1', 222.2.2' and 222.2.3" on the second rotor segment 220.2. This type of arrangement allows each pole lobe in one group to be aligned with the gap between the pole lobes of the opposite group on the rotor segment.
[0054] The third rotor segment 220.3 includes a first set of pole lobes 222.3.1', 222.3.2' and 222.3.3', each of which is offset by 120 electrical degrees relative to each other. The third rotor segment 220.3 further includes a third set of pole lobes 222.3.1", 222.3.2", and 222.3.3", each of which is offset by 120 electrical degrees relative to each other. In addition, the first set of pole lobes 222.3.1', 222.3.2' and 222.3.3 are rotated 180 electrical degrees relative to the second set of pole lobes 222.3.1', 222.3.2' and 222.3.3 on the third rotor segment 220.3. This type of arrangement allows each pole lobe in one group to be aligned with the gap between the pole lobes of the opposite group on the rotor segment.
[0055] According to the arrangement of the magnetic pole lobes on the rotor 206, each rotor segment 220 has a reference angle (e.g., an origin angle or a 0° angle) that is offset from the corresponding reference angle of each of the other rotor segments of the plurality of rotor segments by an offset angle based on the number of phases of the motor and the number of magnetic pole lobes on each rotor segment. Figure 4 As shown, the first rotor segment 220.1 has a first reference angle 400, which is centered on the first magnetic pole lobe 222.1.1' of the first group on the first rotor segment 220.1. In addition, the second reference angle 402 centered on the first magnetic pole lobe 222.2.1' of the first group on the second rotor segment 220.2 is offset by positive 120 degrees relative to the first reference angle 400. In addition, the third reference angle 404 centered on the first magnetic pole lobe 222.3.1' of the first group on the third rotor segment 220.3 is offset by negative 120 degrees relative to the first reference angle 400.
[0056] In addition, each rotor segment 220 includes three pairs of pole lobes on opposite sides of the corresponding winding segment of the second stationary winding 204. Each lobe in the pair is offset by 180 electrical degrees relative to the other lobe in the pair. Figure 4 As shown, the first pole lobe 222.1.1' in the first group on the first rotor segment 220.1 is centered at a first reference angle 400 (e.g., an origin angle or a 0° angle), and the corresponding first pole lobe 222.1.1" in the second group on the first rotor segment 220.1 is offset from the first pole lobe 222.1.1' by 108 electrical degrees. Each other opposing pair of pole lobes on the first rotor segment 220.1 has the same offset.
[0057] The offset of the reference angle between the rotor segments and the offset between the pairs of magnetic pole lobes on different rotor segments form an arrangement on rotor 206 that allows motor 102 to generate three-phase AC output power. In other embodiments, the arrangement of the rotor segments and magnetic pole lobes on the rotor segments may be different based on the phase of the AC output power generated by motor 102.
[0058] Figure 6-8 Graphs are shown of different example waveforms generated during simulated operation of the motor 102. For the simulation, the parameters were set as follows:
[0059] f1: frequency of the first stationary winding = 100 Hz
[0060] f2: Secondary stationary winding frequency = 400Hz
[0061] p: Number of magnetic pole lobes of the motor = 6
[0062] n: rotor speed, in rpm = -6000rpm
[0063]
[0064] f1=fre+f2=-300Hz+400Hz=100Hz
[0065] Figure 6 The second stationary winding 204 (eg, Figure 2 Graph 600 includes three waveforms 602, 604, and 606, which correspond to three different phases of the induced voltage on the second stationary winding 204 within a quarter cycle. The three waveforms 602, 604, and 606 together generate a voltage with a frequency of 400 Hz.
[0066] Figure 7 The first stationary winding 202 (eg, Figure 2 Graph 700 includes three waveforms 702, 704, and 706, which correspond to three different phases of the induced voltage on the first stationary winding 202 within a quarter cycle. The three waveforms 702, 704, and 706 together generate a voltage with a frequency of 100 Hz.
[0067] Figure 8 The motor 102 is shown as the rotor 206 (eg Figure 2 800 of an example torque waveform 802 generated by an electric motor 102 (shown in FIG. 800 ). For a particular operating point of -6000 rpm, the torque waveform 802 produces a constant torque of approximately -36 Nm. Note that in this example, as n changes, the controller 112 of the electric motor 102 changes f1 to maintain 400 Hz on f2.
[0068] Note that the simulation of the electric machine 102 is provided as a non-limiting example. The electric machine 102 may have different operating characteristics at different operating set points.
[0069] The motor disclosed herein has a structure that allows the motor to generate multiple three-dimensional flux paths during operation, each flux path extending transversely through the rotor of the motor in radial and axial directions. The flux paths collectively enable the motor to generate electricity at a desired output frequency by adjusting the AC excitation current as the rotor speed changes. In this way, the frequency of the AC output power is decoupled from the rotor speed of the motor, which is referred to as independent speed, variable frequency. Achieving independent speed, variable frequency in this manner allows the motor to be directly connected to a drive shaft without the need for a CSD.
[0070] Furthermore, since the first winding and the second winding are stationary in the motor, the likelihood of winding degradation during motor operation is reduced relative to conventional motors that include rotating electronic components located on the rotor. This increases the reliability of the motor relative to conventional motors that include rotating electronic components located on the rotor. Furthermore, since the first winding and the second winding are stationary in the motor, the electrical connections of these windings are less complex relative to the electrical connections (e.g., brushes) of conventional motors that include rotating electronic components located on the rotor.
[0071] In this way, the power density, efficiency, reliability of the electric machine are improved, and the cost, weight and complexity are reduced relative to conventional electric machines.The concepts described herein are broadly applicable to many applications where it is desirable to generate AC power at a desired frequency independent of drive speed.
[0072] In one example, an electric machine includes a stator, a first stationary winding coupled to the stator, a second stationary winding coupled to the stator and including a plurality of winding segments corresponding to the number of phases of the electric machine power, and a rotor extending through the stator and the second stationary winding, wherein the rotor includes a plurality of rotor segments, wherein each of the plurality of rotor segments includes a plurality of magnetic pole lobes extending radially from the rotor segment, and wherein two or more magnetic pole lobes of each rotor segment are located on opposite sides of a corresponding winding segment of the second stationary winding. In this example and / or other examples, the number of rotor segments of the rotor may correspond to the number of phases of the electric machine. In this example and / or other examples, each of the plurality of rotor segments may have a reference angle that is offset from a corresponding reference angle of each of the other rotor segments of the plurality of rotor segments by an offset angle based on the number of phases of the electric machine and the number of magnetic pole lobes on each rotor segment. In this example and / or other examples, each rotor segment may include one or more pairs of pole lobes, each pole lobe of a pair of the one or more pairs of pole lobes may be located on an opposite side of a corresponding winding segment of the second stationary winding from the other pole lobe of the pair of pole lobes, and each pole lobe of the pair of pole lobes may be offset by 180 electrical degrees relative to the other pole lobe of the pair of pole lobes. In this example and / or other examples, the motor may be configured to generate three-phase alternating current (AC) power, the second stationary winding may include three winding segments, the rotor may include three rotor segments, each of the three rotor segments may include three pairs of pole lobes, and a reference angle of each rotor segment may be offset by 120 electrical degrees relative to a corresponding reference angle of each of the other rotor segments of the three rotor segments. In this example and / or other examples, the electric machine may further include a controller configured to apply an alternating current (AC) excitation current to one of the first stationary winding or the second stationary winding, the AC excitation current may be based at least on the rotational speed of the rotor, the electric machine may generate an AC output power on the other of the first stationary winding or the second stationary winding based at least on the AC excitation current, and the AC output power may have a desired frequency independent of the rotational speed of the rotor. In this example and / or other examples, applying the AC excitation current to the second stationary winding may generate a magnetic flux path that extends transversely through the rotor in the radial direction and the axial direction of the electric machine and travels through a pair of magnetic pole lobes of the same rotor segment of the rotor, the pair of magnetic pole lobes being located on opposite sides of the corresponding winding segments of the second stationary winding. In this example and / or other examples, the electric machine may be configured to output the AC output power to the AC bus of the aircraft. In this example and / or other examples, the electric machine may be configured to output the AC output power to the propulsion engine of the aircraft. In this example and / or other examples, the rotor may be coupled to a variable speed shaft of the engine of the aircraft.
[0073] In another example, an electric machine includes a stator, a first stationary winding coupled to the stator, a second stationary winding coupled to the stator and including a plurality of winding segments corresponding to the number of phases of the motor power, and a rotor extending through the stator and the second stationary winding, wherein the rotor includes a plurality of rotor segments, wherein each of the plurality of rotor segments includes a plurality of magnetic pole lobes extending radially from the rotor segment, and wherein two or more magnetic pole lobes of each rotor segment are located on opposite sides of a corresponding winding segment of the second stationary winding, and a controller configured to apply an alternating current (AC) excitation current to one of the first stationary winding or the second stationary winding based at least on a rotational speed of the rotor, so that the motor generates an AC output power having a desired frequency on the other of the first stationary winding or the second stationary winding, the desired frequency being independent of the rotational speed of the rotor. In this example and / or other examples, the number of rotor segments of the rotor may correspond to the number of phases of the electric machine. In this example and / or other examples, each rotor segment of the plurality of rotor segments may have a reference angle that is offset from a corresponding reference angle of each of the other rotor segments of the plurality of rotor segments by an offset angle based on the number of phases of the motor and the number of pole lobes on each rotor segment. In this example and / or other examples, each rotor segment may include one or more pairs of pole lobes, each pole lobe of a pair of the one or more pairs of pole lobes may be located on an opposite side of a corresponding winding segment of the second stationary winding from the other pole lobe of the pair of pole lobes, and each pole lobe of the pair of pole lobes may be offset by 180 electrical degrees relative to the other pole lobe of the pair of pole lobes. In this example and / or other examples, the motor may be configured to generate three-phase AC power, the second stationary winding may include three winding segments, the rotor may include three rotor segments, each rotor segment of the three rotor segments may include three pairs of pole lobes, and the reference angle of each rotor segment may be offset by 120 electrical degrees relative to the reference angle of each of the other rotor segments of the three rotor segments. In this example and / or other examples, applying an AC excitation current to the second stationary winding can generate a magnetic flux path that extends transversely through the rotor in the radial direction and axial direction of the motor and travels through a pair of magnetic pole lobes of the same rotor segment of the rotor, the pair of magnetic pole lobes being located on opposite sides of corresponding winding segments of the second stationary winding. In this example and / or other examples, the motor can be configured to output AC output power to an AC bus of an aircraft. In this example and / or other examples, the motor can be configured to output AC output power to a propulsion engine of an aircraft. In this example and / or other examples, the rotor can be coupled to a variable speed shaft of an engine of the aircraft.
[0074] In another example, an electric motor includes a stator, a first stationary winding coupled to the stator, a second stationary winding coupled to the stator and including a plurality of winding segments corresponding to the number of phases of the motor power, and a rotor extending through the stator and the second stationary winding, wherein the rotor includes a plurality of rotor segments, wherein each of the plurality of rotor segments includes a plurality of pole lobes extending radially from the rotor segment, wherein two or more pole lobes of each rotor segment are located on opposite sides of a corresponding winding segment of the second stationary winding; and wherein the electric motor is configured to generate a magnetic flux path based on an AC excitation current applied to the second stationary winding, the magnetic flux path extending transversely through the rotor in a radial direction and an axial direction of the motor and traveling through a pair of pole lobes of the same rotor segment of the rotor, the pair of pole lobes being located on opposite sides of the corresponding winding segment of the second stationary winding.
[0075] The present disclosure includes all novel and non-obvious combinations and sub-combinations of the various features and techniques disclosed herein. The various features and techniques disclosed herein are not required for all examples of the present disclosure. In addition, the various features and techniques disclosed herein may define patentable subject matter in addition to the disclosed examples, and may find utility in other embodiments not expressly disclosed herein.
[0076] Parts List:
[0077] Aircraft 100
[0078] Motor 102
[0079] Engine compartment 104
[0080] Imaginary incision 106
[0081] Engine 108
[0082] Auxiliary shaft 110
[0083] Controller 112 AC electrical bus 114
[0084] Stator 200
[0085] The first stationary winding 202
[0086] The second stationary winding 204
[0087] Rotor 206
[0088] Laminated core 210
[0089] Slot 212
[0090] Winding conductor 214
[0091] Cylindrical cavity 216
[0092] Three winding sections 218.1, 218.2, 218.3 Three rotor sections 220.1, 220.2, 220.3 Three magnetic pole lobes 222.1, 222.2, 222.3 Magnetic flux path 300
[0093] Origin 302
[0094] First reference angle 400
[0095] Second reference angle 402
[0096] The third reference angle 404
[0097] Graph 600
[0098] Three waveforms 602, 604, 606
[0099] Graph 700
[0100] Three waveforms 702, 704, 706
[0101] Graph 800
[0102] Torque waveform 802
Claims
1. A motor (102), comprising: stator (200); a first stationary winding (202) coupled to the stator (200); a second stationary winding (204) coupled to the stator (200) and comprising a plurality of winding segments (218.1, 218.2, 218.3) corresponding to the number of phases of power of the motor (102); and A rotor (206) extending through the stator (200) and the second stationary winding (204), wherein the rotor (206) includes a plurality of rotor segments (220.1, 220.2, 220.3), wherein each rotor segment (220) of the plurality of rotor segments (220.1, 220.2, 220.3) includes a plurality of pole lobes (222.1, 222.2, 222.3) extending radially from the rotor segment (220), and wherein two or more pole lobes (222.1, 222.2, 222.3) of each rotor segment (220) are located on opposite sides of a corresponding winding segment (218) of the second stationary winding (204).
2. The electric machine (102) of claim 1, wherein the number of rotor segments (220) of the rotor (206) corresponds to the number of phases of the electric machine (102).
3. The electric machine (102) of claim 1, wherein each rotor segment (220) of the plurality of rotor segments (220.1, 220.2, 220.3) has a reference angle (400) that is offset from a corresponding reference angle (400) of each of the other rotor segments (220) of the plurality of rotor segments (220.1, 220.2, 220.3) by an offset angle (400), the offset angle being based on the number of phases of the electric machine (102) and the number of pole lobes (222) on each rotor segment (220).
4. The electric machine (102) of claim 3, wherein each rotor segment (220) comprises one or more pairs of pole lobes (222), wherein each pole lobe (222) of a pair of the one or more pairs of pole lobes (222) is located on an opposite side of a corresponding winding segment (218) of the second stationary winding (204) from the other pole lobe (222) of the pair of pole lobes (222), and wherein each pole lobe (222) of the pair of pole lobes (222) is offset by 180 electrical degrees relative to the other pole lobe (222) of the pair of pole lobes (222).
5. The electric machine (102) of claim 4, wherein the electric machine (102) is configured to generate three-phase alternating current power, i.e., three-phase AC power, wherein the second stationary winding (204) includes three winding segments (218.1, 218.2, 218.3), wherein the rotor (206) includes three rotor segments (220.1, 220.2, 220.3), wherein each rotor segment (220) of the three rotor segments (220.1, 220.2, 220.3) includes three pairs of magnetic pole lobes (222), and wherein the reference angle of each rotor segment (220) is offset by 120 electrical degrees relative to the corresponding reference angle of each of the other rotor segments (220) of the three rotor segments (220.1, 220.2, 220.3).
6. The electric machine (102) according to claim 1, further comprising: A controller (112) configured to apply an alternating current (AC) excitation current to one of the first stationary winding (202) or the second stationary winding (204), wherein the AC excitation current is based at least on a rotational speed of the rotor (206), wherein the motor (102) generates an AC output power on the other of the first stationary winding (202) or the second stationary winding (204) based at least on the AC excitation current, and wherein the AC output power has a desired frequency that is independent of the rotational speed of the rotor (206).
7. The electric machine (102) of claim 6, wherein application of the AC excitation current to the second stationary winding (204) generates a magnetic flux path that extends transversely through the rotor (206) in radial and axial directions of the electric machine (102) and travels through a pair of pole lobes (222) of the same rotor segment (220) of the rotor (206) located on opposite sides of a corresponding winding segment (218) of the second stationary winding (204).
8. The electric machine (102) of claim 6, wherein the electric machine (102) is configured to output the AC output power to an AC bus of an aircraft (100).
9. The electric machine (102) of claim 6, wherein the electric machine (102) is configured to output the AC output power to a propulsion engine of an aircraft (100).
10. The electric machine (102) of claim 1, wherein the rotor is coupled to a variable speed shaft of an engine of an aircraft (100).
11. An electric motor (102), comprising: stator (200); a first stationary winding (202) coupled to the stator (200); a second stationary winding (204) coupled to the stator (200) and comprising a plurality of winding segments (218.1, 218.2, 218.3) corresponding to the number of phases of power of the motor (102); a rotor (206) extending through the stator (200) and the second stationary winding (204), wherein the rotor (206) comprises a plurality of rotor segments (220.1, 220.2, 220.3), wherein each rotor segment (220) of the plurality of rotor segments (220.1, 220.2, 220.3) comprises a plurality of pole lobes (222.1, 222.2, 222.3) extending radially from the rotor segment (220), and wherein two or more pole lobes (222) of each rotor segment (220) are located on opposite sides of a corresponding winding segment (218) of the second stationary winding (204); and A controller (112) is configured to apply an alternating current (AC excitation current) to one of the first stationary winding (202) or the second stationary winding (204) based at least on the rotational speed of the rotor (206), so that the motor (102) generates AC output power having a desired frequency, the desired frequency being independent of the rotational speed of the rotor (206) on the other of the first stationary winding (202) or the second stationary winding (204).
12. The electric machine (102) of claim 11, wherein the number of rotor segments (220) of the rotor (206) corresponds to the number of phases of the electric machine (102).
13. The electric machine (102) of claim 11, wherein each rotor segment (220) of the plurality of rotor segments (220.1, 220.2, 220.3) has a reference angle that is offset from a corresponding reference angle of each of the other rotor segments (220) of the plurality of rotor segments (220.1, 220.2, 220.3) by an offset angle based on the number of phases of the electric machine (102) and the number of pole lobes (222) on each rotor segment (220).
14. The electric machine (102) of claim 13, wherein each rotor segment (220) comprises one or more pairs of pole lobes (222), wherein each pole lobe (222) of a pair of the one or more pairs of pole lobes (222) is located on an opposite side of a corresponding winding segment (218) of the second stationary winding (204) from the other pole lobe (222) of the pair of pole lobes (222), and wherein each pole lobe (222) of the pair of pole lobes (222) is offset by 180 electrical degrees relative to the other pole lobe (222) of the pair of pole lobes (222).
15. The electric machine (102) of claim 14, wherein the electric machine (102) is configured to generate three-phase AC power, wherein the second stationary winding (204) includes three winding segments (218.1, 218.2, 218.3), wherein the rotor (206) includes three rotor segments (220.1, 220.2, 220.3), wherein each rotor segment (220) of the three rotor segments (220.1, 220.2, 220.3) includes three pairs of magnetic pole lobes (222.1, 222.2, 222.3), and wherein the reference angle of each rotor segment (220) is offset by 120 electrical degrees relative to the reference angle of each of the other rotor segments (220) of the three rotor segments (220.1, 220.2, 220.3).
16. The electric machine (102) of claim 11, wherein application of the AC excitation current to the second stationary winding (204) generates a magnetic flux path that extends transversely through the rotor (206) in radial and axial directions of the electric machine (102) and travels through a pair of pole lobes (222) of the same rotor segment (220) of the rotor (206) on opposite sides of a corresponding winding segment (218) of the second stationary winding (204).
17. The electric machine (102) of claim 11, wherein the electric machine (102) is configured to output the AC output power to an AC bus of an aircraft (100).
18. The electric machine (102) of claim 11, wherein the electric machine (102) is configured to output the AC output power to a propulsion engine of an aircraft (100).
19. The electric machine (102) of claim 11, wherein the rotor is coupled to a variable speed shaft of an engine of an aircraft.
20. An electric machine (102), comprising: stator (200); a first stationary winding (202) coupled to the stator (200); a second stationary winding (204) coupled to the stator (200) and comprising a plurality of winding segments (218.1, 218.2, 218.3) corresponding to the number of phases of power of the motor (102); and A rotor (206) extending through the stator (200) and the second stationary winding (204), wherein the rotor (206) comprises a plurality of rotor segments (220.1, 220.2, 220.3), wherein each rotor segment (220) of the plurality of rotor segments (220.1, 220.2, 220.3) comprises a plurality of magnetic pole lobes (222.1, 222.2, 222.3) extending radially from the rotor segment (220), wherein two or more magnetic pole lobes (222) of each rotor segment (220) are located in the first on opposite sides of corresponding winding segments (218) of two stationary windings (204); and wherein the motor (102) is configured to generate a magnetic flux path based on an AC excitation current applied to the second stationary winding (204), the magnetic flux path extending transversely through the rotor (206) in radial and axial directions of the motor (102) and traveling through a pair of pole lobes (222) of the same rotor segment (220) of the rotor (206) located on opposite sides of corresponding winding segments (218) of the second stationary winding (204).