Electric machine and method of operating an electric machine

Abstract

A motor (20) is disclosed having a stator (21) and a rotor (22) mounted rotatable relative to the stator (21). The rotor (22) comprises at least one pole pair having two magnets (23). Furthermore, the rotor (22) has at least two recesses (25) extending at least partially through the rotor (22), wherein the recesses (25) are arranged on opposite sides of the rotor (22) and the number of pole pairs of the rotor (22) differs from the number of electromagnetic pole pairs that can be generated during operation of the rotor (22). A method for operating the motor (20) is also disclosed.

Description

[0001] This application relates to an electric motor and a method for operating the electric motor.

[0002] Typically, an electric motor consists of a stator and a rotor that moves relative to the stator. An electric motor can operate as either a motor or a generator to convert electrical energy into kinetic energy or vice versa. During operation, the magnetic field of the rotor interacts with the magnetic field of the stator.

[0003] To generate the rotor magnetic field, the rotor can have permanent magnets. The advantage of using permanent magnets is that there are many different ways to arrange them in the rotor, which is why there are more ways to optimize motor efficiency.

[0004] However, permanent magnets typically account for a large portion of the total cost of an electric motor.

[0005] One problem to be solved is to provide a motor that can be operated effectively. Another problem to be solved is to provide an effective method for operating the motor.

[0006] This task is accomplished through the objectives of the independent claims. Advantageous embodiments and other improvements are shown in the dependent claims.

[0007] According to at least one embodiment of the motor, the motor includes a stator and a rotor mounted rotatable relative to the stator. The stator can have stator windings. For this purpose, the stator can have slots in which the stator windings are arranged. The stator windings can be connected to power electronic devices and are designed to generate a rotating field. The rotor can be an inner rotor or an outer rotor. If the rotor is an inner rotor, the outer surface of the rotor faces the stator. The rotor can be arranged on a shaft. In addition, the rotor has a rotation axis. An air gap can be arranged between the stator and the rotor.

[0008] The rotor has at least one pair of magnetic poles comprising two magnets. The magnets can be permanent magnets or electromagnets. The two magnets can be arranged on opposite sides of the rotor. The magnets can be arranged within the rotor. Alternatively, the magnets can be arranged on the outer side of the rotor. Each magnet has a magnetic axis. The magnetic axis extends parallel to the magnetization direction of the magnet. This means that the magnetic axis connects the two poles of each magnet. The magnetic axes of the magnets can point in the same direction.

[0009] The rotor has at least two recesses that extend at least partially through the rotor. The recesses can be cavities within the rotor.

[0010] The rotor may have a rotor core, which has a core material. Magnets may be arranged on or within the rotor core. The two recesses do not have core material. The core material may be iron.

[0011] The recess can extend from the outer surface of the rotor toward its center in a cross-section passing through the rotor. This means the recess can be directly adjacent to the air gap. The cross-section through the rotor extends in a plane perpendicular to the rotor's axis of rotation. However, the recess can also be completely integrated into the rotor. The recess can extend the same distance through the rotor. For example, the recess can extend partially through the rotor core. The recess can also extend completely through the rotor. This means the recess can extend all the way to the shaft on which the rotor is mounted. Furthermore, the recess can have the same geometry. For example, the recess can have a rectangular shape in cross-section.

[0012] The recesses can be arranged on opposite sides of the rotor. This means that two recesses can be arranged 180° off from each other along the circumference of the rotor. In addition, the recesses have the same main extension direction.

[0013] The number of magnetic pole pairs on a rotor differs from the number of electromagnetic pole pairs that can be generated during rotor operation. A rotor's magnetic pole pair is a pair of magnets. This means that a pole pair is formed by two magnets. The two magnets in each pole pair can be arranged on opposite sides of the rotor. For example, if the rotor has two magnets, then the rotor as a whole has one magnetic pole pair. Electromagnetic pole pairs that can be generated during rotor operation are specifically those used to generate torque during motor operation. Electromagnetic pole pairs are pole pairs of the rotor's magnetic field, which interacts with the stator's magnetic field during operation. If components with a harmonic order greater than 1 in the rotor's magnetomotive force (MOMF) are used to generate torque, the number of magnetic pole pairs and the number of electromagnetic pole pairs on the rotor can differ. The rotor's MOMF can have components with different harmonic orders. Another expression for the MOMF is the excitation curve.

[0014] For example, if the third-order component of the rotor magnetomotive force has a non-zero magnetic flux density, then this component can be used to generate torque. In this case, the rotor has six electromagnetic poles or three pole pairs. To generate six electromagnetic poles, only one pole pair is needed in the rotor. Therefore, the number of pole pairs in the rotor is different from the number of electromagnetic pole pairs that can be generated during the operation of the rotor. In other words, the rotor magnetic field interacting with the stator magnetic field has six electromagnetic poles.

[0015] The magnetic flux density of the harmonic components of the rotor's magnetomotive force depends in particular on the geometry of the rotor's magnets. For example, the two magnets of the rotor can be arranged along the circumference of the rotor. In this case, the magnetic flux density of the harmonic components of the rotor's magnetomotive force depends on the magnitude of the angular range covered by the magnet extension. In this context, this angular range is measured from the center of the rotor in a cross-section passing through the rotor. Furthermore, the magnetic flux density of the harmonic components of the rotor's magnetomotive force can be affected by the introduction of non-magnetic materials into the rotor.

[0016] The motor described herein is based in particular on the idea that the concave portions of the magnet and rotor are arranged such that the magnetic flux density of the components of the rotor's magnetomotive force with orders greater than 1 is greater than the magnetic flux density of the fundamental component of the rotor's magnetomotive force. Furthermore, the motor described herein is based in particular on the idea that the rotor is constructed such that the magnetic flux density of the components of the rotor's magnetomotive force with orders greater than 1 is greater than the magnetic flux density of the fundamental component of the rotor's magnetomotive force.

[0017] Advantageously, the number of magnetic pole pairs in the rotor differs from the number of electromagnetic pole pairs that can be generated during rotor operation, because this reduces the number of magnets required. If the rotor's magnets are permanent magnets, they significantly contribute to the rotor's cost. The cost of the rotor can be significantly reduced by decreasing the number of magnets required or by reducing the size of the rotor's magnets. It has been shown that the rotor described herein can operate with a similar magnetic flux density, but with a lower total mass of permanent magnets than a rotor in which the number of magnetic pole pairs equals the number of electromagnetic pole pairs. The torque of the motor depends directly on the magnetic flux density.

[0018] According to at least one embodiment of the electric motor, the number of pole pairs in the rotor is less than the number of electromagnetic pole pairs that can be generated during rotor operation. This can be achieved by utilizing the component of the rotor's magnetomotive force with an order greater than 1 used for generating torque. Advantageously, this means that fewer pole pairs are required overall, and therefore fewer magnets in the rotor. This can reduce the manufacturing cost of the electric motor.

[0019] According to at least one embodiment of the motor, the magnet is a permanent magnet. This means that the magnet comprises a magnetic material. The magnet can have a cuboid shape. In a cross-section passing through the rotor along a plane perpendicular to the axis of rotation, the magnet can have a rectangular shape. Alternatively, the magnet can have a curved shape in a cross-section passing through the rotor. For example, the magnet extends partially along the circumference of the rotor. Each magnet has a magnetic axis. The magnetic axis is parallel to the magnetization direction of the magnet. That is, the magnetic axis connects the two poles of each magnet. Using permanent magnets in the rotor is advantageous because there are many possibilities for the arrangement and shape of the permanent magnets, and therefore many different ways to improve the efficiency of the motor.

[0020] According to at least one embodiment of the motor, the magnetic axis of the magnet extends perpendicularly to the radial direction in a cross-section passing through the rotor. The cross-section passing through the rotor extends in a plane perpendicular to the rotor's axis of rotation. The magnetic axis of the magnet can extend in the same direction in the cross-section passing through the rotor. Alternatively, the magnetic axis of the magnet can extend in opposite directions. In the cross-section passing through the rotor, the radial direction extends from the center of the rotor to the respective magnet. The magnetic axis of the magnet can be perpendicular to the main extension direction of the magnet in the cross-section passing through the rotor.

[0021] Advantageously, if the magnetic axis of the magnet is perpendicular to the radial direction in the cross-section passing through the rotor, one or more components of the rotor's magnetomotive force used to generate torque can be amplified, and multiple or one components of the magnetomotive force not used to generate torque can be suppressed. The result is efficient operation of the motor.

[0022] According to at least one embodiment of the motor, the rotor includes at least one additional pair of magnetic poles having two additional magnets. The additional magnets can be permanent magnets or electromagnets. The two additional magnets can be arranged on opposite sides of the rotor. The additional magnets can be arranged within the rotor. The additional magnets can be arranged in recesses within the rotor. Alternatively, the additional magnets can be arranged on the outer side of the rotor. The magnetic axes of the additional magnets can point in the same direction. The additional magnets can be arranged circumferentially along the rotor. For example, the additional magnets have an arcuate shape or a curved shape.

[0023] The motor described in this paper is based in particular on the idea that the rotor magnets, recesses, and additional magnets are arranged such that the flux density of the components of the rotor's magnetomotive force (MTF) with an order greater than 1 is greater than the flux density of the fundamental component of the MMF. Because the additional magnets can be arranged along the circumference of the rotor, the flux density of the harmonic components of the rotor's MMF depends on the angular range covered by the extension of the additional magnets. Therefore, the arrangement of the magnets and additional magnets in the rotor as described in this paper can improve the efficiency of the motor.

[0024] According to at least one embodiment of the motor, the other magnets are permanent magnets. That is, the other magnets comprise magnetic materials. The other magnets can have a cuboid shape. In a cross-section passing through the rotor along a plane perpendicular to the axis of rotation, the other magnets can have a rectangular shape. Alternatively, the other magnets can have a curved shape in a cross-section passing through the rotor. For example, the other magnets extend partially along the circumference of the rotor. Each of the other magnets has a magnetic shaft. The magnetic shaft connects the two poles of each other magnet. Using permanent magnets in the rotor is advantageous because there are many possibilities for the arrangement and shape of the permanent magnets, and therefore many different possibilities for improving the efficiency of the motor.

[0025] According to at least one embodiment of the motor, the other pole pairs are formed by at least one electromagnet. This can mean that the additional magnets are each formed by an electrical conductor. During operation of the motor, current is supplied to the electrical conductors by a power source. The electrical conductors can be arranged in recesses in the rotor. The recesses can be adjacent to an air gap. The recesses can also be arranged entirely within the rotor. The electrical conductors can each comprise a conductive material. For example, the electrical conductors can be formed by rods or wires. The electromagnet can also be a coil. In this case, one or more windings of the coil can be arranged in the recesses. The two electrical conductors of the additional pole pair can be arranged on opposite sides of the rotor. This can mean that the two electrical conductors of the additional pole pair are arranged 180° off-center from each other along the circumference of the rotor. Alternatively, the two electrical conductors of the additional pole pair can be arranged less than 180° off-center from each other along the circumference of the rotor. For example, the two electrical conductors of the additional pole pair are arranged less than 120° off-center from each other along the circumference of the rotor.

[0026] By using at least one electromagnet, the motor can be operated more flexibly. The magnetic axis of another magnet can be adjusted by regulating the direction of the current supplied to the conductor. The magnetic axis of another magnet can be rotated 180° by changing the direction of the current supplied to the conductor. Therefore, by superimposing the magnetic fields of one magnet with those of other magnets, the other magnets can be used to amplify or compensate for various components of the rotor's magnetomotive force. If a component of the magnetomotive force is used to generate torque, amplifying that component is advantageous. If a component of the magnetomotive force is not used to generate torque, compensating for or attenuating that component is advantageous.

[0027] According to at least one embodiment of the motor, the magnetic axis of the magnet points in the opposite direction to the magnetic axis of another magnet. This means that the magnetic axis of the magnet forms a 180° angle with the magnetic axis of the other magnet. In this arrangement, it is advantageous to amplify one or more components of the magnetomotive force of the rotor used to generate torque, and to suppress one or more components of the magnetomotive force not used to generate torque.

[0028] According to at least one embodiment of the motor, the magnetic axis of one magnet is perpendicular to the radial direction in the cross-section passing through the rotor, while the magnetic axis of another magnet is not perpendicular to the radial direction in the cross-section passing through the rotor. For example, the magnetic axis of the other magnet is parallel to the radial direction in the cross-section passing through the rotor. That is, the magnetic axes of the magnets and the other magnets can be parallel to each other or antiparallel. In this arrangement of magnets and other magnets, it is advantageous to amplify one or more components of the magnetomotive force of the rotor used to generate torque, and to suppress multiple or one component of the magnetomotive force not used to generate torque.

[0029] According to at least one embodiment of the motor, the extension of the magnet or other magnet along the rotor circumferential direction is greater than 180 electrical angles. The extension of the magnet or other magnet along the rotor circumferential direction can also be less than 180 electrical angles. The extension of the magnet or other magnet along the rotor circumferential direction refers to the extension of the magnet or other magnet along the rotor circumference. For example, the magnet or other magnet can extend along the rotor circumferential direction covering an angle range of 60° in a cross-section passing through the rotor. Therefore, the extension of the magnet or other magnet along the rotor circumferential direction refers to the geometric arrangement of the magnet or other magnet.

[0030] An electrical angle refers to the rotor's magnetic field. If the rotor's magnetic field has two poles, then 360 electrical angles correspond to 360 geometric angles. If the rotor's magnetic field has six poles, then 360 electrical angles correspond to 120 geometric angles. This means that the magnetic flux density of the rotor's magnetic field has three maximum and three minimum values ​​along the rotor circumference. If a magnet or other magnet is arranged along the rotor circumference, or if a magnet or other magnet extends along the rotor circumference, then the geometric extension of that magnet or other magnet can correspond to an electrical angle greater than 180. Alternatively, the geometric extension of that magnet or other magnet can correspond to an electrical angle less than 180. This can be achieved by making the number of magnetic pole pairs of the rotor less than the number of electromagnetic pole pairs that can be generated during rotor operation. It is advantageous to select the extension of the magnet or other magnet along the rotor circumference to be greater than or less than 180 electrical angles, because the magnetic flux density of one or more components of the rotor's magnetomotive force can be selectively changed via the extension of the magnet or other magnet along the rotor circumference.

[0031] According to at least one embodiment of the motor, in a cross-section through the rotor, two recesses extend parallel to the radial direction and at least partially through the rotor. In the cross-section through the rotor, the radial direction extends from the center of the rotor to the outer surface of the rotor. The outer surface can be the side facing the air gap. Each of the two recesses extends parallel to the radial direction. The recesses are used to influence the magnetomotive force (MMF) of the rotor. For example, by introducing the recesses into the rotor, it is possible to influence the magnetic flux density of a component in the rotor's MMF. Therefore, for example, it is possible to suppress or amplify the component. This makes it possible to generate torque using a component in the rotor's MMF with an order greater than 1.

[0032] According to at least one embodiment of the motor, magnets are respectively arranged in one of the recesses of the rotor. This means that each magnet is arranged in one recess of the rotor. The recesses can be directly adjacent to the air gap between the rotor and the stator. The magnets in the recesses can partially or completely fill the recesses. For such a rotor, the third component of the rotor's magnetomotive force can have a larger magnetic flux density than the fundamental wave. This is advantageous for using this component to generate torque.

[0033] According to at least one embodiment of the motor, a non-magnetic insulating material is disposed in the recess. This insulating material can be electrically insulating and / or magnetically insulating. The insulating material can completely fill the recess. For example, the insulating material includes air.

[0034] Recesses with insulating material can act as magnetic flux barriers. This reduces the magnetic flux density of the component of the rotor's magnetomotive force (MTF). For example, if one component of the rotor's MMF is undesirable because it is not used to generate torque, reducing the magnetic flux density of that component is advantageous. High magnetic flux density of the component not used to generate torque leads to motor losses, excessive noise, and rotor core saturation. In particular, the width of the recess with insulating material along the rotor circumference affects the magnetic flux density of the component of the MMF.

[0035] According to at least one embodiment of the motor, in a cross-section passing through the rotor, the main extension direction of the magnet extends in the radial direction. Furthermore, in a cross-section passing through the rotor, the main extension direction of another magnet can extend in the radial direction. This cross-section extends in a plane perpendicular to the rotor's axis of rotation. Therefore, the magnet or another magnet extends in the radial direction. This means that the magnet can have the same main extension direction. The other magnet can also have the same main extension direction. The main extension direction of the magnet can be different from the main extension direction of the other magnet. In this case, the magnets can be arranged to be offset from each other by 180° along the rotor circumference. Other magnets can also be arranged to be offset from each other by 180° along the rotor circumference. According to this embodiment, the magnet or another magnet can be arranged in a recess of the rotor. For such a rotor, the third-order component of the rotor's magnetomotive force can have a larger magnetic flux density than the fundamental wave. This is advantageous for using this component to generate torque.

[0036] According to at least one embodiment of the motor, in the cross-section through the rotor, the main extension direction of the magnet or other magnet is perpendicular to the radial direction. The main extension direction of the magnet or other magnet is the main extension direction in the cross-section through the rotor. If the magnet or other magnet has a rectangular shape in the cross-section through the rotor, then the main extension direction of the magnet or other magnet extends along the longer side of the rectangle. In the cross-section through the rotor, the magnet and other magnets can have the same main extension direction. Here, the main extension direction of the magnet can be parallel to the radial direction, and the main extension direction of the other magnets can be perpendicular to the radial direction. Here, the radial direction refers to the location where the corresponding magnet is arranged. This can mean that the radial direction of the magnet is different from the radial direction of the other magnets. Alternatively, the main extension direction of the magnet can be perpendicular to the radial direction, and the main extension direction of the other magnets can be parallel to the radial direction.

[0037] If the principal extension direction of a magnet or other magnet extends perpendicularly to the radial direction in the cross-section through the rotor, then the magnet and the other magnet can have the same principal extension direction in the cross-section through the rotor. Advantageously, this allows for the amplification of one or more components of the magnetomotive force of the rotor used to generate torque, and allows for the suppression of one or more components of the magnetomotive force not used to generate torque. The result is the ability to operate the motor efficiently.

[0038] According to at least one embodiment of the motor, the motor has at least one additional rotor, wherein the rotor and the additional rotor are arranged along an axis and rotate relative to each other by at least 45 electrical angles. This additional rotor can have the structure described for the rotor of the motor. In this arrangement, the rotor and the additional rotor can have the same or different structures. The rotor and the additional rotor can be arranged on a common shaft. In this case, the rotor and the additional rotor will extend along the axis of their arrangement. The fact that the rotor and the additional rotor rotate relative to each other by at least 45 electrical angles means that the axis of symmetry of the rotor is not parallel to the axis of symmetry of the additional rotor. Advantageously, any non-uniformity in the rotor structure can be compensated for by the additional rotor, and thus the motor can be operated more efficiently overall.

[0039] According to at least one embodiment of the motor, the motor has at least one additional rotor configured similarly to a rotor, wherein the rotor and the additional rotor are arranged along an axis and rotate relative to each other by at least 45 electrical angles. That is, the rotor and the additional rotor have the same structure. The rotor and the additional rotor can be arranged on a common shaft. In this case, the rotor and the additional rotor will extend along the axis of their arrangement. The rotor and the additional rotor can be arranged at a distance from each other. The fact that the rotor and the additional rotor rotate relative to each other by at least 45 electrical angles can mean that the axis of symmetry of the rotor is not parallel to the axis of symmetry of the additional rotor. Two recesses of the rotor can extend along a first axis. Two recesses of the additional rotor can extend along a second axis. The first axis and the second axis enclose an angle greater than 0° with each other. The angle between the first axis and the second axis can depend on the configuration of the rotor and the second rotor. If the rotor and the additional rotor each have four electromagnetic pole pairs that can be generated during operation, then the first axis and the second axis can enclose an angle of 180°. That is, the rotor and the additional rotor can rotate relative to each other by 180°. In this case, the 180° angle corresponds to 360 electrical angles. That is, the rotor and another rotor can rotate 360 ​​electrical degrees relative to each other. When rotating 360 degrees, non-uniformities or asymmetries in the rotor structure can be compensated for by the other rotor. Therefore, the motor can be operated effectively.

[0040] According to at least one embodiment of the motor, the motor includes at least two additional rotors configured similarly to rotors, wherein the rotors and additional rotors are arranged along axes and rotate relative to each other by at least 45 electrical degrees. Two recesses of the rotor can extend along a first axis. Two recesses of the first additional rotor can extend along a second axis. Two recesses of the second additional rotor can extend along a third axis. If the rotors and additional rotors each have six electromagnetic pole pairs that can be generated during operation, the first axis, second axis, and third axis can each form an angle of 120°. That is, the rotors and additional rotors can each rotate relative to each other by 120°. In this case, 120° corresponds to 360 electrical degrees.

[0041] With a larger number of electromagnetic pole pairs, the motor can also have more additional rotors.

[0042] Because the number of electromagnetic pole pairs that can be generated during the operation of the rotor or another rotor can be greater than the number of magnetic pole pairs of the corresponding rotor, the magnetic flux density induced by the stator during operation can penetrate into different materials of the rotor. That is, the magnetic field lines of different magnetic poles can extend through different regions of the rotor. The rotor and the other rotor each include a magnet and a rotor core. Therefore, the magnetic field lines of one pole near the air gap can penetrate only into the rotor core. The magnetic field lines from the other pole can penetrate both into the rotor core and into one of the magnets near the air gap. To compensate for the non-uniformity between different poles, the motor has a rotor and at least one other rotor. Thus, the rotor and at least one other rotor rotate relative to each other so that the magnetic field lines generally extend through the same material.

[0043] Furthermore, a method for operating the motor described herein is also disclosed. Therefore, all features of the described motor are disclosed with respect to the method for operating the motor, and vice versa.

[0044] According to at least one embodiment of the method for operating an electric motor, the components of the rotor's magnetomotive force (MTF) with an order greater than 1 are used to generate torque. This means that the first-order component of the rotor's MMF (called the fundamental wave) is not used to generate torque. Instead, the higher harmonics of the rotor's MMF are used to generate torque. This means that during the operation of the motor, the components of the rotor's MMF with an order greater than 1 interact with the stator magnetic field to generate torque. Therefore, the number of magnetic pole pairs of the rotor is less than the number of electromagnetic pole pairs that can be generated during the operation of the rotor. Magnets and other magnets can be arranged in the rotor to maximize the magnetic flux density for the component of the rotor's MMF used to generate torque. Advantageously, the magnetic flux density of the components of the rotor's MMF not used to generate torque can also be minimized. This makes it possible to operate the electric motor efficiently.

[0045] The electric motor described herein and the method for operating the motor are explained in more detail below with reference to exemplary embodiments and associated drawings.

[0046] Figure 1A and 1B A schematic cross-section through the rotor is shown as an example.

[0047] Figure 2 A schematic cross-section through the motor is shown according to an exemplary embodiment.

[0048] Figure 3A , 3B The motors 4A and 4B are described by way of example.

[0049] Figure 5A and 5B Another motor is described using an example.

[0050] Figure 6A and 6B The magnetic flux density of two motors is plotted using examples.

[0051] Figure 7A , 7B 8A and 8B describe another motor by way of example.

[0052] Figure 9 , 10A Figures 10B and 10B show schematic cross-sections of an electric motor according to an exemplary embodiment.

[0053] exist Figure 11A and 11B In the example, the magnetic flux density of two motors and one motor is plotted according to an exemplary embodiment.

[0054] exist Figure 12A The image shows a cross-section passing through another motor, illustrated by way of example.

[0055] exist Figure 12B The diagram shows a schematic cross-section through the motor according to an exemplary embodiment.

[0056] exist Figure 12C In, it means in Figure 12A The distribution of magnetic flux density in the motor shown.

[0057] exist Figure 12D In, it means in Figure 12B The distribution of magnetic flux density in the exemplary embodiment of the motor shown.

[0058] exist Figure 12E and 12FIn the example, an electric motor and its magnetic flux density are plotted according to an exemplary embodiment.

[0059] Figure 13A An exemplary cross-section through the rotor is shown.

[0060] Figure 13B and 13C Cross sections through the rotor according to an exemplary embodiment are shown.

[0061] Figure 14A , 14B Figures 14C, 14D, 15A, 15B, 16A, 16B, 17A, 17B, 17C, 17D, 17E and 17F respectively show cross sections through the motor according to various exemplary embodiments.

[0062] exist Figure 18A The diagram shows a schematic cross-section through another exemplary embodiment of the motor.

[0063] exist Figure 18B The diagram shows a schematic cross-section through another exemplary embodiment of the motor.

[0064] exist Figure 19A In, it means in Figure 18A The magnetic flux density in the motor shown.

[0065] exist Figure 19B In, it means in Figure 18B The magnetic flux density of the motor shown is shown.

[0066] Figure 20A , 20B Figures 21A and 21B depict the magnetic flux density of motors according to various exemplary embodiments.

[0067] Figure 22A , 22B 22C, 22D, 23A and 23B describe another exemplary embodiment of an electric motor with two additional rotors.

[0068] Figure 24A and 24B Another exemplary embodiment of an electric motor with an additional rotor is described.

[0069] exist Figure 1A The schematic cross-section through rotor 22 is shown as an example. Rotor 22 is not an embodiment. Rotor 22 has four permanent magnets 28 arranged in rotor 22.

[0070] exist Figure 1BThe diagram illustrates a schematic cross-section through another rotor 22, which is not an embodiment. The rotor 22 has four permanent magnets 28 arranged on its outer side 29. The permanent magnets 28 are held on the rotor 22 even at high rotational speeds by means of a mounting member 30. Using permanent magnets 28 on the rotor 22 allows them to be arranged on or within the rotor 22.

[0071] Figure 2 A schematic cross-section through an electric motor 20 according to one embodiment is shown. The electric motor 20 has a stator 21 and a rotor 22 mounted to be rotatable relative to the stator 21. The rotor 22 is an inner rotor arranged in the stator 21. That is, in the cross-section shown, the stator 21 completely surrounds the rotor 22.

[0072] The stator 21 has a plurality of slots 31. Slots 31 are arranged in the stator 21. Stator windings 32 are arranged in the slots 31. The stator windings 32 may have coils wound around teeth 33 of the stator 21, wherein the teeth 33 are arranged between every two slots 31. The stator windings 32 comprise a conductive material. Alternatively, the stator windings 32 may comprise conductive rods arranged in the slots 31. An air gap 26 is arranged between the stator 21 and the rotor 22. The slots 31 are directly adjacent to the air gap 26.

[0073] The rotor 22 has a pair of magnetic poles including two magnets 23. The magnets 23 are respectively arranged in recesses 25 within the rotor 22. Here, the recesses 25 extend from the air gap 26 to the shaft 34 on which the rotor 22 is arranged. That is, the recesses 25 extend parallel to the radial direction in the cross-section passing through the rotor 22. Each radial direction extends from the center of the rotor 22 toward the air gap 26. The rotor 22 includes a rotor core 35. The recesses 25 extend completely through the rotor core 35.

[0074] Furthermore, the two recesses 25 are arranged 180° offset from each other along the circumference of the rotor 22. This means that the two recesses 25 are arranged on opposite sides of the rotor 22. Since magnets 23 are arranged in the recesses 25, the main extending direction of the magnets 23 extends radially in the cross-section through the rotor 22. Each magnet 23 completely fills one of the recesses 25. Each magnet 23 is a permanent magnet. The magnetic axis of the magnet 23 is indicated by an arrow. The magnetic axis of the magnet 23 is perpendicular to the radial direction in the cross-section through the rotor 22. The magnetic axes of the two magnets 23 extend in the same direction. Along the circumference of the rotor 22, the magnets 23 extend to cover an area less than 60°.

[0075] The rotor 22 also has additional pole pairs including two additional magnets 24. These additional magnets 24 are respectively arranged in recesses 25 within the rotor 22. The recesses 25 are directly adjacent to the air gap 26. The recesses 25 extend from the air gap 26 into the rotor 22. This means that the recesses 25 are arranged within the rotor core 35. The distance the recesses 25 containing the additional magnets 24 extend through the rotor 22 is less than the distance the recesses 25 containing the magnets 23 extend through the rotor.

[0076] The recesses 25 where additional magnets 24 are arranged extend circumferentially along the rotor 22, covering a range of at least 30°. For example, the recesses 25 where additional magnets 24 are arranged extend circumferentially along the rotor 22, covering a range of at least 50°. Preferably, the recesses 25 where additional magnets 24 are arranged extend circumferentially along the rotor 22, covering a range of 60°. The recesses 25 where additional magnets 24 are arranged are configured to be offset from each other by 180° along the circumferential direction of the rotor 22. This means that the additional magnets 24 are arranged on opposite sides of the rotor 22.

[0077] The additional magnets 24 partially fill the recesses 25. The additional magnets 24 extend circumferentially along the rotor 22. That is, the additional magnets 24 each have the shape of a circular segment. Therefore, the additional magnets 24 have a curved shape.

[0078] The additional magnet 24 is a permanent magnet. The magnetic axis of the additional magnet 24 is indicated by an arrow. The magnetic axis of the additional magnet 24 is parallel to the radial direction in the cross-section passing through the rotor 22. The magnetic axes of the two additional magnets 24 extend in the same direction. That is, the magnetic axis of one additional magnet 24 points towards the center of the rotor 22, and the magnetic axis of the other additional magnet 24 points towards the air gap 26. The magnetic axis of magnet 23 points in the opposite direction to the magnetic axis of the additional magnet 24. Therefore, the magnetic axis of magnet 23 forms a 180° angle with the magnetic axis of the additional magnet 24.

[0079] Therefore, the rotor 22 has 2 magnetic pole pairs. The number of electromagnetic pole pairs that can be generated during the operation of the rotor 22 is 3. Therefore, the number of magnetic pole pairs of the rotor 22 differs from the number of electromagnetic pole pairs that can be generated during the operation of the rotor 22. The electromagnetic pole pairs that can be generated during the operation of the rotor 22 are described in more detail in the following figures.

[0080] In the form of an example, Figure 3A A schematic cross-section through motor 20 is shown. Motor 20 is not an embodiment. Figure 2 Compared to the rotor 22 shown, Figure 3AThe rotor 22 of the motor 20 has only an additional magnet 24. The rotor 22 does not have a recess 25 in which the magnet 23 is arranged. The additional magnet 24 extends along the circumference of the rotor 22 to cover an angular range of 60°.

[0081] Figure 3B It shows Figure 3A The simulated magnetic flux density distribution in the cross-section shown is illustrated. The magnetic field of rotor 22 has two magnetic poles.

[0082] Figure 4A It shows Figure 3A The simulated magnetic flux density in the air gap 26 of the motor 20 shown. Plotted in radians along the angle of the air gap 26 on the x-axis. The position of the 0° angle is... Figure 3A The x-axis is used for marking. On the y-axis, the magnetic flux density is plotted in Tesla. The magnetic field in air gap 26 therefore has two electromagnetic poles.

[0083] Figure 4B It shows Figure 3A The simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 shown are illustrated. The order of the components is plotted on the x-axis. On the y-axis, the flux density is plotted as normalized to 1. The first-order component exhibits the largest flux density. Additionally, the third-order component has a flux density greater than 0.6. It has been shown that the third-order component has its maximum flux density when the additional magnets 24 extend circumferentially along the rotor 22 to cover an angular range of 60°. When the third-order component is used to generate torque, the rotor 22 has three electromagnetic pole pairs. However, because the flux density of the first-order component is greater than that of the third-order component, the efficiency of the motor 20 decreases. The relatively high flux density of the first-order component, which is not used to generate torque, leads to losses in the stator 21, high noise generation, and saturation of the rotor core 35.

[0084] Figure 5A An example schematic cross-section through another motor 20 is shown. Motor 20 is not an embodiment. Figure 3A Compared to the rotor 22 shown, Figure 5A The rotor 22 of the motor 20 shown additionally has two recesses 25. The recesses 25 are arranged in a manner similar to... Figure 2 The recess 25 shown in Figure 2 Magnet 23 is arranged in the middle. Figure 5A The recess 25 does not contain the material of the rotor core 35. A non-magnetic insulating material 27 is disposed in the recess 25. For example, air may be present in the recess 25.

[0085] Figure 5B It shows Figure 5AThe diagram shows the distribution of simulated magnetic flux density in the cross-section. The recess 25 serves as a magnetic flux barrier, so that the magnetic field of the rotor 22 has six electromagnetic poles.

[0086] exist Figure 6A In China, targeting Figure 3A The motor 20 shown uses solid lines to indicate the simulated magnetic flux density in the air gap 26, and for Figure 5A The motor 20 shown uses dashed lines to illustrate the simulated magnetic flux density in the air gap 26. On the x-axis, the angle along the air gap 26 is plotted in radians. On the y-axis, the magnetic flux density is plotted in Tesla. Figure 5A The magnetic field of the motor 20 shown has six electromagnetic poles in the air gap 26. Figure 3A The magnetic field of the motor 20 shown has only two electromagnetic poles in the air gap 26.

[0087] exist Figure 6B In the middle, black bars were used to draw... Figure 3A The simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 shown are plotted using white bars. Figure 5A The simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 shown are illustrated. The order of the components is plotted on the x-axis. On the y-axis, the magnetic flux density is plotted as normalized to 1. Figure 3A Compared to the motor 20 shown, Figure 5A The magnetic flux density of the third-order component of the motor 20 shown is significantly increased. Additionally, for Figure 5A For the motor 20, the magnetic flux density of the first-order component is significantly smaller than that of the third-order component. Therefore, the introduction of the recess 25 results in a relative decrease in the magnetic flux density of the first-order component and a relative increase in the magnetic flux density of the third-order component. Thus, the third-order component of the magnetomotive force of the rotor 22 can be used more effectively to generate torque.

[0088] Figure 7A An example schematic cross-section of another motor 20 is shown. Motor 20 is not an embodiment. Figure 2 Compared to the rotor 22 shown, Figure 7A In the rotor 22 of the motor 20 shown, no additional magnet 24 is arranged in the recess 25. Air can exist in the recess 25.

[0089] Figure 7B It shows Figure 7A The simulated magnetic flux density distribution in the cross-section shown is illustrated. The magnetic field of rotor 22 has six electromagnetic poles.

[0090] Figure 8A Showing the target Figure 7AThe simulated magnetic flux density in the air gap 26 of the motor 20 shown is plotted in radians along the x-axis, at the angle of the air gap 26. On the y-axis, the magnetic flux density is plotted in Tesla. The magnetic field in the air gap 26 therefore has six electromagnetic poles.

[0091] Figure 8B Drawn Figure 7A The simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 shown are illustrated. The order of the components is plotted on the x-axis. On the y-axis, the magnetic flux density is plotted as normalized to 1. The third-order component shows the maximum value of the magnetic flux density. The first-order component also has a relatively high value of magnetic flux density.

[0092] Figure 9 It shows Figure 2 The rotor 22 shown is Figure 5A and 7A The combination of rotors 22 shown. On the upper left, it is shown... Figure 5A and 7A The motor 20 is shown. On the upper right, a schematic cross-section through the motor 20 according to one embodiment is shown, wherein the rotor 22 of the motor 20 is... Figure 5A and 7A The combination of rotors 22 shown.

[0093] Figure 10A It shows crossing according to Figure 9 A schematic cross-section of the motor 20 shown in the exemplary embodiment. The structure of the stator 21 is arbitrary.

[0094] Figure 10B It shows Figure 10A The diagram shows the distribution of simulated magnetic flux density in the cross-section. The rotor 22 has four magnetic poles and six electromagnetic poles. That is, the rotor 22 has two magnetic pole pairs and three electromagnetic pole pairs.

[0095] exist Figure 11A In the middle, black lines are used to show Figure 5A The simulated magnetic flux density in the air gap 26 of the motor 20 shown is illustrated by dashed lines. Figure 7A The simulated magnetic flux density in the air gap 26 of the motor 20 shown is illustrated using gray lines. Figure 10A An embodiment of the motor 20 is shown. On the x-axis, the angle along the air gap 26 is plotted in radians. On the y-axis, the magnetic flux density is plotted in Tesla. Therefore, Figure 10A An exemplary embodiment of the rotor 22 shown has six electromagnetic poles.

[0096] exist Figure 11B In the middle, drawn in black with... Figure 5AThe simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 of the rotor 22 shown are plotted in light gray. Figure 7A The simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 of the rotor 22 shown are plotted in gray. Figure 10A An exemplary embodiment of rotor 22 is shown. The order of the components is plotted on the x-axis. The magnetic flux density is plotted on the y-axis as normalized to 1. For Figure 10A For the rotor 22 shown, the first-order component is significantly reduced compared to the third-order component. The first-order component is reduced to below 0.05. This is achieved by the magnetic axis of magnet 23 forming a 180° angle with the magnetic axis of the other magnet 24.

[0097] Therefore, the magnetic axis of magnet 23 points in the opposite direction to the magnetic axis of magnet 24. This means that the first-order component of the magnetic field of magnet 23 is offset by 180° relative to the first-order component of the magnetic field of magnet 24. Therefore, the two first-order components compensate for each other. This is in Figure 11B This can be seen from the significantly reduced magnetic flux density of the first-order component. Furthermore, the third-order component of the magnetic field of magnet 23 is offset by 360° relative to the third-order component of the magnetic field of magnet 24. This means that the third-order components are added together. Therefore, Figure 10A The third-order component of the rotor 22 shown has a larger magnetic flux density than the third-order components of the other two rotors 22.

[0098] exist Figure 12A The diagram illustrates, exemplarily, a cross-section through a motor 20. Motor 20 is not an embodiment. The rotor 22 of motor 20 has six permanent magnets 28. The permanent magnets 28 are arranged circumferentially on the outer surface 29 of rotor 22. The magnetic axes of adjacent permanent magnets 28 point in opposite directions. The magnetic axes of the permanent magnets 28 are parallel to the radial direction in the cross-section through rotor 22.

[0099] For comparison, Figure 12B It shows crossing Figure 10A A schematic cross-section of an exemplary embodiment of the motor 20 shown.

[0100] Figure 12C It shows Figure 12A The diagram shows the distribution of simulated magnetic flux density in the cross-section. The rotor 22 has six magnetic poles and six electromagnetic poles. That is, the ratio of the number of magnetic poles to the number of electromagnetic poles is an integer of 1.

[0101] For comparison, Figure 12D It shows Figure 12BThe diagram shows the distribution of simulated magnetic flux density in the cross-section. The rotor 22 has four magnetic poles and six electromagnetic poles. Here, the ratio of magnetic poles to electromagnetic poles is 2 / 3. In the motor 20 described here, the ratio of magnetic poles to electromagnetic poles is not an integer.

[0102] exist Figure 12E In the middle, dashed lines are used to show Figure 12A The simulated magnetic flux density in the air gap 26 of the motor 20 shown is illustrated using solid lines. Figure 12B The embodiment of the motor 20 shown is illustrated. The angle along the air gap 26 is plotted in radians along the x-axis. The magnetic flux density is plotted in Tesla along the y-axis. Both motors 20 have six electromagnetic poles.

[0103] exist Figure 12F In the middle, white bars were used to draw... Figure 12A The simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 of the rotor 22 shown are plotted using black bars. Figure 12B The simulated harmonic components of the magnetic flux density in the air gap 26 of the motor 20 in the rotor 22 embodiment shown are illustrated. The order of the components is plotted on the x-axis. On the y-axis, the magnetic flux density is plotted as normalized to 1. Therefore, for Figure 12B In the exemplary embodiment of the rotor 22 shown, the ratio of the magnetic flux density of the third-order component to the magnetic flux density of the first-order component is greater than […]. Figure 12A The ratio of the third-order component to the first-order component of the magnetic flux density of the rotor 22 shown is given. Therefore, the motor 20 described herein can be operated more efficiently.

[0104] Figure 13A It shows crossing Figure 12A The diagram shows a schematic cross-section of the rotor 22 of the motor 20. A dashed line indicates a 180° electrical angle. The permanent magnets 28 extend to cover approximately 180° of electrical angle. This corresponds to a 60° geometric angle.

[0105] Figure 13B A schematic cross-section through the rotor 22 according to an exemplary embodiment is shown. The rotor 22 generally has Figure 2 The structure is shown in the diagram. A 180° electrical angle is indicated by dashed lines. Other magnets 24 extend circumferentially along the rotor 22 to cover angles less than 180°, meaning the extension of the other magnets 24 circumferentially along the rotor 22 is less than 180°. In the rotor 22 described herein, the extension of additional magnets 24 circumferentially along the rotor 22 can be arbitrarily adjusted to increase the efficiency of the motor 20. Figure 13A In the example of rotor 22 shown, the maximum possible extension of permanent magnet 28 along the circumference of rotor 22 is 180 electrical angles.

[0106] Figure 13C A schematic cross-section through a rotor 22 according to another embodiment is shown. The rotor 22 generally has... Figure 2 The structure is shown in the diagram. A dashed line indicates a 180° electrical angle. Other magnets 24 extend circumferentially along the rotor 22 by more than 180° electrical angle, meaning that the extensions of the other magnets 24 circumferentially along the rotor 22 are each greater than 180° electrical angle. Advantageously, in the rotor 22 described herein, the extension of additional magnets 24 circumferentially along the rotor 22 can be arbitrarily adjusted to increase the efficiency of the motor 20.

[0107] Figure 14A , 14B Figures 14C and 14D illustrate exemplary embodiments of the motor 20, wherein the rotor 22 has six electromagnetic poles.

[0108] exist Figure 14A In the middle, it is shown that passing through Figure 10A The schematic cross-section of the motor 20 shown is shown.

[0109] Figure 14B A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 14A Unlike the rotor 22 shown, the additional magnets 24 do not extend circumferentially along the rotor 22. The additional magnets 24 are integrally arranged within the rotor 22. Each of the additional magnets 24 has a rectangular shape in cross-section passing through the rotor 22. Furthermore, the main extension direction of the additional magnets 24 is parallel to the main extension direction of magnet 23. Therefore, the main extension direction of the additional magnets 24 is perpendicular to the radial direction in cross-section passing through the rotor 22. The magnetic axes of the additional magnets 24 point in the same direction. The magnetic axes of the additional magnets 24 point in the opposite direction to the magnetic axis of magnet 23. This means that the magnetic axes of the additional magnets 24 are perpendicular to their main extension directions. The additional magnets 24 are arranged circumferentially along the rotor 22 at positions offset by 90° relative to the position of magnet 23.

[0110] exist Figure 14C The image shows a schematic cross-section through a motor 20 according to another exemplary embodiment. Figure 14B Compared to the rotor 22 shown, two additional magnets 24 are arranged in the rotor 22, instead of each additional magnet 24 being arranged in the rotor. In this case, the two additional magnets 24 are arranged in the rotor 22 in a V-shape. Therefore, the magnetic axes of the additional magnets 24 point in different directions. The magnetic axes of the additional magnets 24 form an angle greater than 90° with the magnetic axis of the magnet 23. The main extension direction of the additional magnets 24 is not parallel to the main extension direction of the magnet 23.

[0111] exist Figure 14DThe image shows a schematic cross-section through a motor 20 according to another exemplary embodiment. Figure 14A Compared to the exemplary embodiment shown, no magnet 23 is arranged in the recess 25, but insulating material 27 is arranged in the recess 25. The rotor 22 has two magnets 23 and two additional magnets 24. The two magnets 23 are directly adjacent to one of the recesses 25 and are arranged on opposite sides of the rotor 22 in the cross-section passing through the rotor 22. The two additional magnets 24 are also directly adjacent to one of the recesses 25 and are arranged on opposite sides of the rotor 22 in the cross-section passing through the rotor 22. That is, one magnet 23 and one additional magnet 24 are arranged directly adjacent to each recess 25. The magnets 23 and the additional magnets 24 are each arcuate in shape. The magnetic axes of the magnets 23 point in the same direction and travel parallel to the radial direction in the cross-section passing through the rotor 22. The magnetic axes of the additional magnets 24 point in the same direction, but in a different direction than the magnetic axes of the magnets 23. The magnetic shaft of the additional magnet 24 travels in a direction parallel to the radial direction in the cross section passing through the rotor 22.

[0112] Figure 15A A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 14A Compared to the rotor 22 shown, Figure 15A The rotor 22 shown has a total of four additional magnets 24. Every two additional magnets 24 are arranged on opposite sides of the rotor 22. That is, every two additional magnets 24 are arranged 180° off-center from each other along the circumference of the rotor 22. The additional magnets 24 are arranged in recesses 25 within the rotor 22. The recesses 25 are directly adjacent to the air gap 26. The additional magnets 24 extend circumferentially along the rotor 22 and have a curved or arcuate shape. The magnetic axes of the additional magnets 24 arranged accordingly on opposite sides of the rotor 22 point in the same direction. The magnetic axis of each of the additional magnets 24 is parallel to the radial direction in the cross-section passing through the rotor 22. The rotor 22 thus has three magnetic pole pairs and five electromagnetic pole pairs.

[0113] Figure 15B A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 15A Compared to the exemplary embodiment shown, the rotor 22 has six additional magnets 24 instead of four. Therefore, the rotor 22 has four magnetic pole pairs and seven electromagnetic pole pairs.

[0114] Figure 16A A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 10ACompared to the embodiment shown, the rotor 22 has a total of four magnets 23. The magnets 23 are arranged in recesses 25 within the rotor 22. The recesses 25 extend parallel to the radial direction in a cross-section passing through the rotor 22. Two magnets 23 are arranged on opposite sides of the rotor 22. The magnetic axes of the magnets 23 extend perpendicular to the radial direction in a cross-section passing through the rotor 22. The magnetic axes of every two magnets 23, arranged to be offset from each other by 180° along the circumference of the rotor 22, form an angle of 180° with each other. The main extending directions of every two magnets 23 form an angle of less than 90° with each other. The magnetic axes of these two magnets 23 form an angle of greater than 90° with each other. Figure 10A Two additional magnets 24 are arranged as shown in the exemplary embodiment illustrated. (With) Figure 10A Compared to the rotor 22 shown, the magnetic axes of the additional magnets 24 are angled together by 180°. The rotor 22 therefore has three magnetic pole pairs and four electromagnetic pole pairs.

[0115] Figure 16B A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 16A Compared to the embodiment shown, no magnet 23 is arranged in the recess 25 and no additional magnet 24 is arranged there, while... Figure 16A Magnets 23 are arranged in the recesses 25. For example, air is present in these recesses 25. In addition, the rotor 22 has two other recesses 25, each of which is equipped with a magnet 25. This means that the magnets 23 and the other magnets 24 are arranged in the recesses 25. Figure 10A The rotor 22 is arranged as shown in the diagram. Therefore, the rotor 22 has two magnetic pole pairs and three electromagnetic pole pairs.

[0116] Figure 17A A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 10A Compared to the rotor 22 shown, no magnets 23 are arranged in the recesses 25 extending parallel to the radial direction in the cross-section of the rotor 22. For example, air exists in the recesses 25 extending parallel to the radial direction through the rotor 22. Magnets 23 are respectively arranged in the recesses 25 extending circumferentially along the rotor 22. The two magnets 23 are each arc-shaped. Here, the two magnets 23 extend along the circumference of the rotor 22 at an angle covering 90°. In this arrangement, each of the magnets 23 is adjacent to one of the recesses 25 extending parallel to the radial direction through the rotor 22. The magnetic axes of the magnets 23 are parallel to the radial direction. Furthermore, the magnetic axes of the magnets 23 point in opposite directions. That is, both magnetic axes point towards the air gap 26. Figure 17A The rotor 22 shown does not have an additional magnet 24. Therefore, the rotor 22 has one magnetic pole pair and two electromagnetic pole pairs.

[0117] Figure 17BA schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 17A Compared to the rotor 22 shown, magnets 23 are arranged in each of the recesses 25 extending parallel to the radial direction. The magnets 23 are combined... Figure 10A The arrangement is shown, except that the magnetic axes of magnets 23 point in opposite directions. Two additional magnets 24 are arranged as shown... Figure 17A As shown in the diagram, magnet 23. Rotor 22 has two magnetic pole pairs and four electromagnetic pole pairs.

[0118] Figure 17C A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. No magnets 23 and no additional magnets 24 are arranged in the recesses 25 extending parallel to the radial direction. For example, air is present in these recesses 25. Two magnets 23 are arranged in the recesses 25 extending circumferentially along the rotor 22. Each magnet 23 has an arcuate shape. Each magnet 23 is arranged directly adjacent to one of the recesses 25 extending radially through the rotor 22. The magnetic axes of the magnets 23 are parallel to the radial direction and point in opposite directions. Additionally, two additional magnets 24 are arranged in the recesses 25 of the rotor 22. These additional magnets 24 extend circumferentially along the rotor 22 at appropriate positions, each having an arcuate shape. Each of the additional magnets 24 is arranged circumferentially along the rotor 22 between the recesses 25 extending radially through the rotor 22 and the magnet 23. The magnetic axes of the additional magnets 24 point in different directions. The rotor 22 has two magnetic pole pairs and four electromagnetic pole pairs.

[0119] Figure 17D A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 17C Compared to the rotor 22 shown, the magnet 23 is arranged in one of the recesses 25. The magnet 23 is arranged in a recess 25 that extends parallel to the radial direction and has no magnet 23 directly adjacent to it. The magnetic axis of the magnet 23 in this recess 25 is perpendicular to the radial direction. The rotor 22 has four electromagnetic pole pairs.

[0120] Figure 17E A schematic cross-section through a motor 20 according to another embodiment is shown. Figure 17CCompared to the rotor 22 shown, magnets 23 and additional magnets 24 are symmetrically distributed along the circumference of rotor 22. In this case, each magnet 23 is directly adjacent to one of the recesses 25 in which neither magnet 23 nor additional magnet 24 is arranged. Magnets 23 are arranged 180° off-center relative to each other along the circumference of rotor 22. The other magnets 24 are arranged 180° off-center relative to each other along the circumference of rotor 22. Magnets 23 are also arranged 90° off-center relative to the other magnets 24 along the circumference of rotor 22. The magnetic axes of magnets 23 and the other magnets 24 point towards the center of rotor 22. Rotor 22 has two magnetic pole pairs and four electromagnetic pole pairs.

[0121] Figure 17F A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 17D Compared to the rotor 22 shown, a magnet 23 is arranged in each of the recesses 25 extending through the rotor 22 in a direction parallel to the radial direction. The magnets 23 are arranged as follows: Figure 10A As shown, the difference is that the magnetic axis of magnet 23 points in the opposite direction. Rotor 22 has three magnetic pole pairs and four electromagnetic pole pairs.

[0122] Figure 18A A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 10A Compared to the rotor 22 shown, the additional pole pairs are formed by electromagnets. For each additional pole pair, the rotor 22 has two recesses 25. An electrical conductor 36 is arranged in each of the recesses 25. The electrical conductor 36 is designed to supply current to it. The electrical conductors 36 in two adjacent recesses 25 respectively form electromagnets. For example, each electromagnet is formed by a coil. The electrical conductors 36 of an additional magnet 24 are arranged to be offset from each other by less than 180° along the circumference of the rotor 22. The two additional magnets 24 are arranged symmetrically with respect to magnet 23 in the cross-section through the rotor 22.

[0123] When the electromagnet is not energized, rotor 22 has one magnetic pole pair and one electromagnetic pole pair (first operating state). If current is supplied to the electromagnet, the magnetic axis of the other magnet 24 can be adjusted by the direction of the current. If the magnetic axis of the other magnet 24 extends in the opposite direction to the magnetic axis of magnet 23, this corresponds to... Figure 2 The situation shown is the second operating state. In this case, rotor 22 has three electromagnetic pole pairs. If the magnetic axis of the additional magnet 24 extends in the same direction as the magnetic axis of magnet 23, then rotor 22 has one electromagnetic pole pair and can operate with a high magnetic flux density (third operating state). Therefore, Figure 18AThe structure shown allows for the selection of three different operating states as needed. Furthermore, the number of electromagnetic pole pairs can be changed and adjusted during operation of the motor 20. Additionally, the magnetic flux density of the magnetomotive force of the rotor 22 at the air gap 26 can be changed and adjusted during operation of the motor 20.

[0124] Figure 18B A schematic cross-section through a motor 20 according to another exemplary embodiment is shown. Figure 18A Compared to the embodiment shown, the magnet 23 is arranged in a manner similar to Figure 10A The additional magnet 24 shown. The recess 25 does not extend completely through the rotor 22. Electrical conductors 36 are arranged in the two recesses 25, which are offset from each other by 180° along the circumference of the rotor 22. The electrical conductors 36 form other magnets 24. The electrical conductors 36 are each offset by 90° from the center of the magnet 23 along the circumference of the rotor 22. This embodiment can achieve... Figure 18A Operate as described.

[0125] Figure 19A It is shown that in the first operating state Figure 18A The diagram shows the distribution of simulated magnetic flux density in the cross-section. In this case, the additional magnet 24 is not energized. Therefore, this is the first operating state. The rotor 22 has one electromagnetic pole pair. In this operating state, the motor 20 is able to operate at a high rotational speed.

[0126] Figure 19B It is shown that in the second operating state Figure 18A The diagram shows the distribution of simulated magnetic flux density in the cross-section. In this case, current is supplied to another magnet 24 such that the magnetic axis of the other magnet 24 points in the opposite direction to the magnetic axis of magnet 23. Therefore, this is the second operating state. The rotor 22 has three electromagnetic pole pairs. In this operating state, the motor 20 can operate efficiently.

[0127] exist Figure 20A In the diagram, the simulated magnetic flux density in the air gap 26 under the first operating state is shown in solid lines, and the simulated magnetic flux density in the air gap 26 under the second operating state is shown in dashed lines. On the x-axis, the angle along the air gap 26 is plotted in radians. On the y-axis, the magnetic flux density is plotted in Tesla. In the second operating state, the rotor 22 has six electromagnetic poles.

[0128] exist Figure 20BIn the diagram, black bars represent the simulated harmonic components of the magnetic flux density in the air gap 26 under the first operating state, and white bars represent the simulated harmonic components under the second operating state. The order of the components is plotted on the x-axis. On the y-axis, the magnetic flux density is plotted as normalized to 1. In the first operating state, the first-order component of the magnetomotive force of the rotor 22 is used to generate torque. In the second operating state, the third-order component of the magnetomotive force of the rotor 22 is used to generate torque. In this case, since the ratio of the magnetic flux density of the third-order component to that of the first-order component is much greater than the ratio in the first operating state, the motor 20 can operate more efficiently in the second operating state than in the first operating state.

[0129] exist Figure 21A In the diagram, the simulated magnetic flux density in the air gap 26 under the first operating state is shown in solid lines, and the simulated magnetic flux density in the air gap 26 under the third operating state is shown in dashed lines. On the x-axis, the angle along the air gap 26 is plotted in radians. On the y-axis, the magnetic flux density is plotted in Tesla. Therefore, a larger torque can be generated in the third operating state than in the first operating state.

[0130] exist Figure 21B In the diagram, black bars represent the simulated harmonic components of the magnetic flux density in the air gap 26 under the first operating state, and white bars represent the simulated harmonic components of the magnetic flux density in the air gap 26 under the third operating state. The order of the components is plotted on the x-axis. On the y-axis, the magnetic flux density is plotted as normalized to 1. In the third operating state, the motor 20 can operate more efficiently than in the first operating state.

[0131] Figure 22A It shows crossing Figure 10A A schematic cross-section of the embodiment of the motor 20 shown is illustrated. In the cross-section, the magnetic field lines representing the magnetic flux density induced by the stator 21 during operation are shown. The magnetic flux density, shown by solid lines, extends along the air gap 26 through the rotor core 35. The magnetic flux density, shown by dashed lines, extends along the air gap 26 once through the rotor core 35 and once through one of the other magnets 24. This results in different magnetic flux densities at different poles.

[0132] Figure 22B It shows crossing Figure 22A The diagram shows a schematic cross-section of rotor 22. The arrows shown on the outer side of rotor 22 provide reference points for the following two figures.

[0133] exist Figure 22C The diagram shows a schematic cross-section through an additional rotor 37. The additional rotor 37 has... Figure 22B The structure shown. Additionally, another rotor 37 is relative to... Figure 22B The rotor 22 shown rotates by 120°. An arrow on the outer side of the additional rotor 37 indicates a 120° rotation. 120° corresponds to 360 electrical degrees.

[0134] Figure 22D A schematic cross-section of another rotor 37 is shown. The other rotor 37 has... Figure 22B The structure shown. Additionally, this additional rotor 37 is relative to... Figure 22C The additional rotor 37 shown rotates 120°. The arrow on the outer side of this additional rotor 37 indicates the 120° rotation. This means that the additional rotor 37 is relative to... Figure 22B The rotor 22 shown rotates 120°. 120° corresponds to 360 electrical degrees.

[0135] Figure 23A It shows Figure 22B The rotor 22 shown and Figure 22C and 22D The other rotor 37 shown is arranged along an axis. Furthermore, rotor 22 and the other rotor 37 are each rotated 120° relative to each other.

[0136] exist Figure 23B In, it is shown Figure 23A Rotor 22 and another rotor 37. Rotor 22 and the other rotor 37 can be arranged on a common shaft 34 in the motor 20 (not shown). Figure 23B As shown, rotor 22 and the other rotor 37 can be arranged to be directly adjacent to each other. Along the axis of their arrangement, rotor 22 and the other rotor 37 have the same extension.

[0137] exist Figure 24A In the example shown, rotor 22 and additional rotor 37 are illustrated. Rotor 22 and additional rotor 37 have Figure 17A The structure shown is as follows. The magnetic axis of the magnet 23 of rotor 22 is parallel to the radial direction in the cross-section passing through rotor 22. In this case, the magnetic axis of magnet 23 points to the outer surface 29 of rotor 22. The magnetic axis of the magnet 23 of the other rotor 37 is parallel to the radial direction in the cross-section passing through the other rotor 37. Here, the magnetic axis of magnet 23 points to the center of the other rotor 37. That is, the magnetic axis points away from the outer surface 29 of the other rotor 37. Therefore, rotor 22 and the other rotor 37 each have two electromagnetic pole pairs. Rotor 22 and the other rotor 37 are arranged along an axis in motor 20. Rotor 22 and the other rotor 37 can be arranged on a common shaft 34 (not shown). Furthermore, rotor 22 and the other rotor 37 are rotated 90° relative to each other. Figure 24AThe arrow in the middle indicates a 90° rotation.

[0138] Figure 24B It shows Figure 24A Rotor 22 and another rotor 37. Rotor 22 and the other rotor 37 are arranged directly adjacent to each other in the motor 20. Along the axis of their arrangement, rotor 22 and the other rotor 37 have the same extension.

[0139] Explanation of reference numerals in the attached figures

[0140] 20: Electric motor

[0141] 21: Stator

[0142] 22: Rotor

[0143] 23: Magnet

[0144] 24: Other magnets

[0145] 25: concave part

[0146] 26: Air gap

[0147] 27: Insulation materials

[0148] 28: Permanent magnet

[0149] 29: Outer surface

[0150] 30: Installation components

[0151] 31: slot

[0152] 32: Stator winding

[0153] 33: Teeth

[0154] 34: Axis

[0155] 35: Rotor core

[0156] 36: Electrical conductor

[0157] 37: The other rotor

Claims

1. An electric motor (20) having a stator (21) and a rotor (22) mounted to be rotatable relative to said stator (21), wherein, The rotor (22) includes: - Having at least one magnetic pole pair with two magnets (23), - Includes at least one additional magnetic pole pair of two additional magnets (24), wherein the magnetic axis of said magnet (23) points in the opposite direction to the magnetic axis of said additional magnet (24), and - Extending at least partially through at least two recesses (25) of the rotor (22), wherein, - The recess (25) is arranged on the opposite side of the rotor (22), and - The number of magnetic pole pairs of the rotor (22) is different from the number of electromagnetic pole pairs that can be generated during the operation of the rotor (22). - Each magnet (23) is directly adjacent to two electromagnetic poles arranged in the rotor core (35) of the rotor (22) along the circumference of the rotor (22). - Each additional magnet (24) is directly adjacent to two electromagnetic poles arranged in the rotor core (35) along the circumference of the rotor (22). - The magnetic axes of the magnets (23) point in the same direction, and - The magnetic axes of the other magnet (24) point in the same direction.

2. The motor (20) according to claim 1, wherein, The number of magnetic pole pairs of the rotor (22) is less than the number of electromagnetic pole pairs that can be generated during the operation of the rotor (22).

3. The motor (20) according to claim 1, wherein, The magnet (23) is a permanent magnet.

4. The motor (20) according to claim 1, wherein, The magnetic axis of the magnet (23) is perpendicular to the radial direction in the cross section passing through the rotor (22).

5. The motor (20) according to claim 1, wherein, The additional magnets (24) are respectively arranged in the recesses (25) in the rotor (22).

6. The motor (20) according to claim 1, wherein, The additional magnets (24) are respectively arranged in the recesses (25) in the rotor (22), and the additional magnets (24) partially fill the recesses (25).

7. The motor (20) according to claim 1, wherein, The rotor (22) includes four recesses (25) without a magnet (23) and another magnet (24).

8. The motor (20) according to claim 1, wherein, The other magnet (24) is a permanent magnet.

9. The motor (20) according to claim 1, wherein, The additional magnetic pole pair is formed by at least one electromagnet.

10. The motor (20) according to claim 1, wherein, The magnetic axis of the magnet (23) is perpendicular to the radial direction in the cross section passing through the rotor (22), and wherein the magnetic axis of the other magnet (24) is not perpendicular to the radial direction in the cross section passing through the rotor (22).

11. The motor (20) according to claim 1, wherein, The extension of the magnet (23) or the other magnet (24) along the circumference of the rotor (22) is greater than 180 electrical angles.

12. The motor (20) according to claim 1, wherein, The extension of the magnet (23) or the other magnet (24) along the circumference of the rotor (22) is less than 180 electrical angles.

13. The motor (20) according to claim 1, wherein, The two recesses (25) extend at least partially through the rotor (22) in a cross-section parallel to the radial direction.

14. The motor (20) according to claim 1, wherein, The magnets (23) are respectively arranged in one of the recesses (25) of the rotor (22).

15. The motor (20) according to claim 1, wherein, A non-magnetic insulating material (27) is arranged in the recess (25).

16. The motor (20) according to claim 1, wherein, The main extension direction of the magnet (23) extends radially in the cross section passing through the rotor (22).

17. The motor (20) according to claim 1, comprising at least one additional rotor (37) configured similarly to the rotor (22), wherein, The rotor (22) and the other rotor (37) are arranged along an axis and rotate relative to each other by at least 45 electrical angles.

18. A method of operating the motor (20) according to claim 1, wherein, The component of the magnetomotive force of the rotor (22) with an order greater than 1 is used to generate torque.

Images