A rotary transformer

Abstract

A rotary transformer (100a-c) for the transfer of electrical signals to a rotor (810) of an electric rotating machine (800). The rotary transformer (100a-c) comprises a stationary unit (102) and a rotatable unit (104) rotatable about an axis of rotation (105) in relation to the stationary unit (102). The stationary unit (102) comprises a first core part (106a- b) holding one or more primary windings (108) of the rotary transformer (100a-c). The rotatable unit (104) comprises a second core part (110a-e) holding one or more secondary windings (112) of the rotary transformer (100a-c). The second core part (110a-e) is annular and configured to surround and to rotate about the axis of rotation (105). The second core part (110a-e) comprises two or more members (120a-f) spaced apart from one another in the direction of rotation (R) of the second core part (110a-b) about the axis of rotation (105). The two or more members (120a-f) are detectable by one or more sensors (136a-d) so as to detect the rotary position of the rotatable unit (104).

Description

[0001] A ROTARY TRANSFORMER

[0002] Technical field

[0003] Aspects of the present invention relate to a rotary transformer for the transfer of electrical signals to a rotor of an electric rotating machine.

[0004] Background

[0005] In general, an electric rotating machine comprises a stator and a rotor rotatable about an axis of rotation in relation to the stator. In general, at least one of the rotor and stator may be provided with one or more windings, one or more permanent magnets, or one or more other elements interacting with the stator or rotor. Some electric rotating machines are equipped with a fluid system for cooling one or more of the rotor and stator, since during operation of the electric rotating machine one or more of the rotor and stator may be heated to such a degree that cooling is advisable. Some electric rotating machines may be provided with a rotary transformer to transfer electrical signals to the rotor of the electric rotating machine.

[0006] Summary

[0007] The inventors of the present invention have found drawbacks in conventional rotary transformers for the transfer of electrical signals to the rotor of an electric rotating machine. For example, the structure of some conventional rotary transformers is too complex.

[0008] An object of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions.

[0009] The above and further objects are solved by the subject matter of the independent claims. Further advantageous embodiments of the invention can be found in the dependent claims.

[0010] According to a first aspect of the invention, the above mentioned and other objects are achieved with a rotary transformer for the transfer of electrical signals to a rotor of an electric rotating machine, wherein the rotary transformer comprises a stationary unit, and a rotatable unit rotatable about an axis of rotation in relation to the stationary unit, wherein the stationary unit comprises a first core part holding one or more primary windings of the rotary transformer, wherein the rotatable unit comprises a second core part holding one or more secondary windings of the rotary transformer, wherein the second core part is annular and configured to surround and to rotate about the axis of rotation, wherein the second core part comprises two or more members spaced apart from one another in the direction of rotation of the second core part about the axis of rotation, and wherein the two or more members are detectable by one or more sensors so as to detect the rotary position of the rotatable unit.

[0011] An advantage of the rotary transformer according to the first aspect is a less complex structure of the rotary transformer in relation to conventional solutions, for example compared to conventional rotary transformers having a conventional encoder wheel functioning as the detected part in a conventional rotary position detection solution. In the rotary transformer according to the first aspect, the detected part, i.e., said two or more members, may instead be described to be more integrated into the rotary transformer and / or into the rotating second core part of the rotary transformer. An advantage of the rotary transformer according to the first aspect is that a more robust rotary transformer is provided, for example because the detected part, i.e., said two or more members, may be described to be more integrated into the rotary transformer and / or into the rotating second core part of the rotary transformer. An advantage of the rotary transformer according to the first aspect is that the stability of the rotatable unit of the rotary transformer, and / or of the second core part of the rotatable unit, upon rotation is improved. An advantage of the rotary transformer according to the first aspect is that an improved rotary position detection of the rotatable unit is provided. An advantage of the rotary transformer according to the first aspect is that a more robust rotary position detection of the rotatable unit is provided, which, for example, is less sensitive to wear, for example because the detected part, i.e., said two or more members, may be described to be more integrated into the rotary transformer and / or into the rotating second core part of the rotary transformer. An advantage of the rotary transformer according to the first aspect is that a less bulky, or a more compact, rotary transformer in relation to conventional solutions can be provided, for example because the rotating second core part having the two or more members takes up less space in relation to a separate conventional rotating core part and a separate conventional encoder wheel of a conventional rotary transformer. An advantage of the rotary transformer according to the first aspect is an improved transfer of electrical signals to and / or from the rotor of an electric rotating machine. An advantage of the rotary transformer according to the first aspect is that an improved rotary transformer is provided. An advantage of the rotary transformer according to the first aspect is an improved electric rotating machine by providing the electric rotating machine with the innovative rotary transformer. For example, a less bulky electric rotating machine is provided because of a less bulky rotary transformer.

[0012] The electrical signals transferred by the rotary transformer may comprise electrical energy, electric current, and / or electric signals including data or information.

[0013] According to an advantageous embodiment of the rotary transformer according to the first aspect, the two or more members form position indicators detectable by the one or more sensors. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit.

[0014] According to a further advantageous embodiment of the rotary transformer according to the first aspect, the rotary transformer comprises a rotary position detector for detecting the rotary position of the rotatable unit, wherein the rotary position detector comprises the two or more members. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0015] According to another advantageous embodiment of the rotary transformer according to the first aspect, the rotary position detector is configured to detect the rotary position of the rotatable unit in relation to the stationary unit. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0016] According to yet another advantageous embodiment of the rotary transformer according to the first aspect, the rotary position detector comprises one or more sensors configured to be immobile in relation to the rotatable unit, wherein the sensor is configured to detect one or more of the group of:

[0017] • the two or more members; and

[0018] • position indicators formed by the two or more members.

[0019] An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0020] According to still another advantageous embodiment of the rotary transformer according to the first aspect, the one or more sensors comprises / comprise one or more of the group of:

[0021] • an inductive sensor;

[0022] • a capacitive sensor;

[0023] • a magnetic field sensor;

[0024] • a Hall-effect sensor;

[0025] • an optical sensor; and

[0026] • an ultrasonic sensor.

[0027] An advantage of these embodiments is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0028] According to an advantageous embodiment of the rotary transformer according to the first aspect, the two or more members are made of a ferromagnetic or ferrimagnetic material. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer. According to a further advantageous embodiment of the rotary transformer according to the first aspect, the two or more members are made of a material comprising or consisting of a ferromagnetic metal or a ferromagnetic metal alloy. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0029] According to another advantageous embodiment of the rotary transformer according to the first aspect, one or more of the first and second core parts is / are made of a ferromagnetic or ferrimagnetic material. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0030] According to yet another advantageous embodiment of the rotary transformer according to the first aspect, one or more of the first and second core parts is / are made of a material comprising or consisting of a ferromagnetic metal or a ferromagnetic metal alloy. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0031] According to still another advantageous embodiment of the rotary transformer according to the first aspect, one or more of the second core part and members forms / form two or more recesses, wherein in the direction of rotation of the second core part about the axis of rotation a recess of the two or more recesses is positioned between every two members of the two or more members. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0032] According to an advantageous embodiment of the rotary transformer according to the first aspect, the two or more members have axial extensions, wherein the two or more recesses define the axial extensions of the two or more members. According to a further advantageous embodiment of the rotary transformer according to the first aspect, the two or more members have radial extensions, wherein the two or more recesses define the radial extensions of the two or more members.

[0033] According to another advantageous embodiment of the rotary transformer according to the first aspect, the two or more recesses are air-filled.

[0034] According to yet another advantageous embodiment of the rotary transformer according to the first aspect, the two or more recesses are at least partly filled with one or more first materials different from the material of one or more of the members and second core part. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer. An advantage of this embodiment is a further improved stability of the rotatable unit of the rotary transformer, and / or of the second core part of the rotatable unit, upon rotation. An advantage of this embodiment is that cooling fluid losses are avoided when the rotary transformer is cooled by way of a cooling fluid, which may be oil, or any other cooling liquid.

[0035] According to still another advantageous embodiment of the rotary transformer according to the first aspect, the first material comprises or consists of a polymer or a polymer composite. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer. An advantage of this embodiment is a further improved stability of the rotatable unit of the rotary transformer, and / or of the second core part of the rotatable unit, upon rotation.

[0036] According to an advantageous embodiment of the rotary transformer according to the first aspect, the two or more members are covered by the first material. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer. An advantage of this embodiment is a further improved stability of the rotatable unit of the rotary transformer, and / or of the second core part of the rotatable unit, upon rotation.

[0037] According to a further advantageous embodiment of the rotary transformer according to the first aspect, the second core part has a first side facing the first core part, wherein the second core part has one or more second sides facing away from the first core part, and wherein at the first side of the second core part the second core part comprises a compartment holding the one or more secondary windings.

[0038] According to another advantageous embodiment of the rotary transformer according to the first aspect, the compartment of the second core part is annular.

[0039] According to yet another advantageous embodiment of the rotary transformer according to the first aspect, at the second side of the second core part the second core part comprises the two or more members. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer. An advantage of this embodiment is a further improved stability of the rotatable unit of the rotary transformer, and / or of the second core part of the rotatable unit, upon rotation.

[0040] According to still another advantageous embodiment of the rotary transformer according to the first aspect, the second core part comprises two or more projections spaced apart from one another in the direction of rotation of the second core part about the axis of rotation, wherein the two or more projections form the two or more members. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0041] According to an advantageous embodiment of the rotary transformer according to the first aspect, the two or more members are integrally formed with the second core part. An advantage of this embodiment is a further improved rotary transformer. An advantage of this embodiment is a further improved rotary position detection of the rotatable unit of the rotary transformer.

[0042] According to a further advantageous embodiment of the rotary transformer according to the first aspect, the first core part is annular and configured to surround the axis of rotation.

[0043] According to another advantageous embodiment of the rotary transformer according to the first aspect, the first core part has a first side facing the second core part, wherein the first core part has one or more second sides facing away from the second core part, and wherein at the first side of the first core part the first core part comprises a compartment holding the one or more primary windings.

[0044] According to still another advantageous embodiment of the rotary transformer according to the first aspect, the compartment of the first core part is annular.

[0045] According to yet another advantageous embodiment of the rotary transformer according to the first aspect, the outer radius of the second core part is equal to the outer radius of the first core part. An advantage of this embodiment is a further improved rotary transformer.

[0046] According to an advantageous embodiment of the rotary transformer according to the first aspect, the inner radius of the second core part is equal to the inner radius of the first core part. An advantage of this embodiment is a further improved rotary transformer.

[0047] According to a second aspect of the invention, the above mentioned and other objects are achieved with an electric rotating machine comprising a stator, a rotor rotatable about an axis of rotation in relation to the stator, and a rotary transformer according to any one of the embodiments disclosed above or below. Advantages of the electric rotating machine according to the second aspect and its embodiments correspond to the above- or below-mentioned advantages of the rotary transformer according to the first aspect and its embodiments.

[0048] According to a third aspect of the invention, the above mentioned and other objects are achieved with a vehicle comprising one or more of the group of:

[0049] • a rotary transformer according to any one of the embodiments disclosed above or below; and

[0050] • an electric rotating machine according to any one of the embodiments disclosed above or below.

[0051] Advantages of the vehicle according to the third aspect and its embodiments correspond to the above- or below-mentioned advantages of the rotary transformer according to the first aspect and its embodiments.

[0052] The vehicle may be a wheeled vehicle, i.e. a vehicle having wheels. The vehicle may for example be a bus, a tractor vehicle, a heavy vehicle, a truck, or a car. The tractor vehicle, and / or the truck, may, or may be configured to, haul, or pull, a trailer. However, other types of vehicles are possible. The vehicle may be referred to as a motor vehicle. The vehicle may be an electric vehicle, EV, for example a hybrid vehicle or a hybrid electric vehicle, HEV, or a battery electric vehicle, BEV. Thus, a hybrid electric vehicle, HEV, and a battery electric vehicle, BEV, are versions, or examples, of an electric vehicle, EV. The EV may comprise one or more electric rotating machines or electric motors. The vehicle may comprise a combustion engine. For some embodiments, the vehicle may include only a combustion engine for the propulsion of the vehicle.

[0053] The vehicle may comprise a powertrain. The powertrain may be configured in accordance with any one of the embodiments disclosed above or below. The powertrain of the vehicle may comprise one or more of the group of: a combustion engine; an electric battery cell unit; an electric battery arrangement; and an electric battery pack. The above-mentioned features and embodiments of the rotary transformer, the electric rotating machine and the vehicle, respectively, may be combined in various possible ways providing further advantageous embodiments.

[0054] Further advantageous embodiments of the rotary transformer, the electric rotating machine and the vehicle according to the present invention and further advantages with the embodiments of the present invention emerge from the detailed description of embodiments.

[0055] Brief Description of the Drawings

[0056] Embodiments of the invention will now be illustrated, for exemplary purposes, in more detail by way of embodiments and with reference to the enclosed drawings, where similar references are used for similar parts, in which:

[0057] Figure 1 is a schematic circuit diagram illustrating aspects of embodiments of the rotary transformer according to the first aspect of the invention and of the of the electric rotating machine according to the second aspect of the invention;

[0058] Figure 2 is a schematic sectional side view of an embodiment of the rotary transformer according to the first aspect of the invention;

[0059] Figure 3 is a schematic sectional side view of another embodiment of the rotary transformer according to the first aspect of the invention;

[0060] Figure 4 is an enlargement of the rotary transformer of figure 3;

[0061] Figure 5 schematically illustrates cross-section views of alternative structures of the stationary and rotatable units of embodiments of the rotary transformer according to the first aspect of the invention;

[0062] Figure 6 is a schematic sectional perspective view of the stationary and rotatable units of an embodiment of the rotary transformer according to the first aspect of the invention;

[0063] Figure 7 is another schematic sectional perspective view of the stationary and rotatable units of the rotary transformer of figure 6; Figure 8A is a schematic perspective view of an embodiment of the second core part of the rotatable unit of an embodiment of the rotary transformer according to the first aspect of the invention;

[0064] Figure 8B is a schematic side view of the second core part of figure 8A;

[0065] Figure 8C is a schematic top view of the second core part of figure 8A;

[0066] Figure 9 is a schematic perspective view of another embodiment of the second core part of the rotatable unit of an embodiment of the rotary transformer according to the first aspect of the invention;

[0067] Figure 10 is a schematic perspective view of still another embodiment of the second core part of the rotatable unit of an embodiment of the rotary transformer according to the first aspect of the invention;

[0068] Figure 11 is a schematic perspective view of yet another embodiment of the second core part of the rotatable unit of an embodiment of the rotary transformer according to the first aspect of the invention;

[0069] Figure 12A is a schematic perspective view of an embodiment of the first core part of the stationary unit of an embodiment of the rotary transformer according to the first aspect of the invention;

[0070] Figure 12B is a schematic side view of the first core part of figure 12A;

[0071] Figure 12C is a schematic bottom view of the first core part of figure 12A;

[0072] Figure 13 is a schematic diagram illustrating aspects of embodiments of the rotary transformer according to the first aspect of the invention;

[0073] Figure 14 is a schematic end view of an embodiment of the electric rotating machine according to the second aspect of the invention;

[0074] Figure 15 schematically illustrates a cross-section of the electric rotating machine along D-D in figure 14;

[0075] Figure 16 is a schematic diagram illustrating a version of a fluid system for cooling one or more of the rotor and stator of an embodiment of the electric rotating machine according to the second aspect of the invention; and

[0076] Figure 17 is a schematic side view of an embodiment of the vehicle according to the third aspect. Detailed Description

[0077] Figure 1 shows a schematic circuit diagram illustrating general aspects of embodiments of the rotary transformer 10Oa-c for the transfer of electrical signals to a rotor 810 of an electric rotating machine 800 according to the first aspect of the invention. The electrical signals transferred by the rotary transformer 100a-c may comprise electrical energy, electric current, and / or electric signals including data or information. The circuit diagram also illustrates general aspects of embodiments of the electric rotating machine 800 according to the second aspect of the invention. A stator 806 of the electric rotating machine 800 may be provided with electrical energy from an electric battery arrangement 906 via a first power converter 702. The first power converter 702 is configured to convert DC power from the electric battery arrangement 906 to AC power to be provided to the stator 806 of the electric rotating machine 800 and / or configured to convert AC power from the stator 806 of the electric rotating machine 800 to DC power to be provided to the electric battery arrangement 906. For some embodiments, the first power converter 702 may be referred to as an inverter. The rotary transformer 100a-c may be connectable, or connected, more specifically electrically connected, to the electric battery arrangement 906 via a second power converter 704, which may be referred to as a rotor current controller and / or an inverter. The rotary transformer 100a-c may be connectable, or connected, more specifically electrically connected, to the rotor 810 of an electric rotating machine 800 via a third power converter 706, which may be referred to as a rotating rectifier. The second power converter 704 may be configured to convert DC power from the electric battery arrangement 906 to AC power to be provided to rotary transformer 100a-c and / or configured to convert AC power from the rotary transformer 10Oa-c to DC power to be provided to the electric battery arrangement 906. The third power converter 706 may be configured to convert AC power from the rotary transformer 10Oa-c to DC power to be provided to the rotor 810 of an electric rotating machine 800 and / or configured to convert DC power from the rotor 810 of an electric rotating machine 800 to AC power to be provided to rotary transformer 10Oa-c. For some embodiments, it may be defined that the rotary transformer 10Oa-c additionally is configured to transfer electrical signals from the rotor 810 of the electric rotating machine 800. As illustrated in figure 1 , the rotary transformer 100a-c may be connectable, or connected, to the AC sides of the second and third second power converters 704, 706. With reference to figure 2, aspects of embodiments of the rotary transformer 100a for the transfer of electrical signals to a rotor 810 of an electric rotating machine 800 according to the first aspect of the invention are schematically illustrated. The rotary transformer 100a may also be referred to as a rotatory, rotating, or rotatable transformer. The rotary transformer 100a includes a stationary unit 102 and a rotatable unit 104. The rotatable unit 104 is rotatable about an axis of rotation 105 in relation to the stationary unit 102. For some embodiments, the stationary unit 102 may be referred to as a stationary part, or a stator part. For some embodiments, the rotatable unit 104 may be referred to as a rotatable part, or rotor part.

[0078] With reference to figures 2, 6, 8A-C and 12A-C, the stationary unit 102 includes a first core part 106a holding one or more primary windings 108 of the rotary transformer 100a. The rotatable unit 104 includes a second core part 1 10a; 1 10b holding one or more secondary windings 1 12 of the rotary transformer 100a. With reference to figure 2, for some embodiments, it may be defined that the first core part 106a and the second core part 110a form a gap 11 1 , such as an air gap, between one another. For some embodiments, it may be defined that the first core part 106a is spaced (apart) from the second core part 1 10a to form a gap 11 1 , such as an air gap, between the first core part 106a and the second core part 1 10a. For some embodiments, it may be defined that the stationary unit 102 is spaced (apart) from the rotatable unit 104 to form a gap 1 1 1 , such as an air gap, between the stationary unit 102 and the rotatable unit 104.

[0079] With reference to figures 6 and 8A-C, the second core part 1 10a; 1 10b is annular and configured to surround and to rotate about the axis of rotation 105. For some embodiments, it may be defined that the rotatable unit 104 is attachable, directly or indirectly, to the rotor 810 of the electric rotating machine 800. With reference to figures 2 and 7, for some embodiments, the first core part 106a may comprise, or be referred to as, a first core half, or a first half of a cup core. For some embodiments, the second core part 1 10a; 1 10b may comprise, or be referred to as, a second core half, or a second half of a cup core. With reference to figures 8A-C, which illustrates an embodiment of the second core part 110a, the second core part 1 10a comprises two or more members 120a-f spaced apart from one another in the direction of rotation R of the second core part 1 10a about the axis of rotation 105. The two or more members 120a-f are detectable, or sensed, by one or more sensors 136a; 136b; 136c; 136d (see figures 2 and 4) so as to detect the rotary (or, rotational, or angular) position of the rotatable unit 104, for example the rotary position of the rotatable unit 104 in relation to the stationary unit 102. For some embodiments, the member 120a-f may comprise, or be described as, a ribbon, a tooth, or a protrusion. For some embodiments, it may be defined that the second core part 1 10a includes two or more projections 120a-f spaced apart from one another in the direction of rotation R of the second core part 1 10a about the axis of rotation 105, wherein the two or more projections 120a-f form the two or more members 120a-f. For some embodiments, the two or more members 120a-f may be distributed in the direction of rotation R of the second core part 1 10a.

[0080] With reference to figure 8A, for some embodiments, the second core part 1 10a may comprise three or more members 120a-f spaced apart from one another in the direction of rotation R. For some embodiments, the second core part 1 10a may comprise four or more members 120a-f spaced apart from one another in the direction of rotation R. For some embodiments, the second core part 110a may comprise five or more members 120a-f spaced apart from one another in the direction of rotation R. For some embodiments, the second core part 1 10a may comprise six or more members 120a-f spaced apart from one another in the direction of rotation R.

[0081] With reference to figure 8A-C, for some embodiments, the two or more members 120a- f may be integrally formed with the second core part 1 10a. The fact that the members 120a-f are integrally formed with the second core part 1 10a implies, or means, that the members 120a-f and the second core part 1 10a are formed into a single piece and / or are formed from a single piece. For example, a piece of material may be formed into the second core part 1 10a and the members 120a-f integrally formed therewith, for example by way any suitable cutting procedure, such as milling, or by way of casting. Expressed alternatively, the fact that the members 120a-f are integrally formed with a second core part 110a may imply, or may mean, that the members 120a-f and the second core part 1 10a are made of a single piece of material. However, for other embodiments, the members 120a-f may be attached to the second core part 110a, for example by welding, or by way of any other means of attachment.

[0082] With reference to figures 2 and 8A, for some embodiments, it may be defined that the second core part 110a; 1 10b has a first side 1 14 facing the first core part 106a and that the second core part 1 10a; 1 10b has one or more second sides 1 16 facing away from the first core part 106a. For some embodiments, at the first side 1 14 of the second core part 1 10a; 1 10b, the second core part 1 10a; 1 10b may comprise, or form, a compartment 1 18 holding the one or more secondary windings 1 12.

[0083] With reference to figures 6 and 12A-C, for some embodiments, the first core part 106a may be annular and configured to surround the axis of rotation 105. With reference to figures 2, 7 and 12B-C, for some embodiments, it may be defined that the first core part 106a has a first side 132 facing the second core part 1 10a; 110b and that the first core part 106a has one or more second sides 134 facing away from the second core part 1 10a; 1 10b. For some embodiments, at the first side 132 of the first core part 106a, the first core part 106a may comprise, or form, a compartment 130 holding the one or more primary windings 108.

[0084] With reference to figures 6 and 12C, for some embodiments, the compartment 1 18 of the second core part 1 10a; 1 10b may be annular. For some embodiments, the compartment 130 of the first core part 106a may be annular.

[0085] With reference to figures 6 and 8A-C, for some embodiments, at the second side 1 16 of the second core part 1 10a; 1 10b, the second core part 1 10a; 1 10b may comprise the two or more members 120a-f ; 120g. However, in figure 13, several alternative locations of the two or more members 120a-f are schematically illustrated. In figure 13, members 120a-d illustrate positions of the members 120a-d essentially corresponding to the embodiment of figure 8A-C. However, in figure 13, four members 120a-d are present instead of six members 120a-f as in figure 8A. References 120g illustrate alternative locations of the two or more members 120g at the second core part 1 10g. Figure 6 also illustrates alternative shapes, forms and locations of the two or more members 120g.

[0086] With reference to figure 8A-C, for some embodiments, the two or more members 120a- f may be made of a ferromagnetic or ferrimagnetic material, for example ferrite, iron, or zinc. However, other materials are possible. For some embodiments, the two or more members 120a-f may be made of a material comprising or consisting of a ferromagnetic metal or a ferromagnetic metal alloy, for example iron, zinc, MnZn, NiZn, or an iron alloy. However, other materials are possible. With reference to figures 8A-C and 12A-B, one or more of the first and second core parts 106a, 1 10a may be made of a ferromagnetic or ferrimagnetic material, for example of any sort mentioned above. However, other materials are possible. For some embodiments, one or more of the first and second core parts 106a, 1 10a may be made of a material comprising or consisting of a ferromagnetic metal or a ferromagnetic metal alloy, for example of any sort mentioned above. However, other materials are possible.

[0087] With reference to figure 8A-C, for some embodiments, it may be defined that one or more of the second core part 1 10a and members 120a-f forms / form two or more recesses 122a-f, for example at the second side 1 16 of the second core part 1 10a. In the direction of rotation R of the second core part 1 10a about the axis of rotation 105, a recess 122a-f of the two or more recesses 122a-f is positioned between every two members 120a-f of the two or more members 120a-f. With reference to figure 8A, for some embodiments, it may be defined that the two or more members 120a-f have axial extensions 124, wherein the two or more recesses 122a-f define the axial extensions 124 of the two or more members 120a-f. For some embodiments, it may be defined that the two or more members 120a-f have radial extensions 126, wherein the two or more recesses 122a-f define the radial extensions 126 of the two or more members 120a-f. For some embodiments, the two or more recesses 122a-f may be air-filled, and / or possibly filled with any cooling fluid present.

[0088] With reference to figure 9, for some embodiments, the two or more recesses 122a-f may be at least partly filled with one or more first materials 128 different from the material of one or more of the members 120a-f and second core part 110c. The first material may be described to have different material properties in relation to the material of one or more of the members 120a-f and second core part 110c. For some embodiments, the first material 128 may be a material which is not electrically conductive, or non-conductive.

[0089] For some embodiments, the first material 128 may comprise or consist of a polymer or a polymer composite, for example a thermoplastic polymer, such as polypropylene. However, other materials are possible. For alternative embodiments, the two or more members 120a-f may be covered by the first material 128.

[0090] With reference to figures 10 and 11 , two other embodiments of the second core part 1 10d; 1 10e are schematically illustrated. Apart from the shape of the second core part 1 10d; 1 10e, of the two or more members and of the two or more recesses, features of the second core part 1 10d; 1 10e illustrated in figures 10 and 11 may correspond to features of the second core parts 110a; 1 10b disclosed above in connections with figures 1 to 8A-C and are thus not repeated here.

[0091] With refence to figures 8A and 12A, for some embodiments, the outer radius r1 of the second core part 110a may be equal to the outer radius r3 of the first core part 106a. For some embodiments, the inner radius r2 of the second core part 1 10a may be equal to the inner radius r4 of the first core part 106a.

[0092] With reference to figures 3 and 4, another embodiment of the rotary transformer 100b for the transfer of electrical signals to a rotor 810 of an electric rotating machine 800 according to the first aspect of the invention is schematically illustrated. The stationary unit 102 of the rotary transformer 100b may be described to be positioned between the rotatable unit 104 and the axis of rotation 105. The stationary unit 102 of the rotary transformer 100b may be described to be positioned inside the rotatable unit 104. For some embodiments, the first core part 106b of the stationary unit 102 may be described to be positioned between the second core part 1 10f of the rotatable unit 104 and the axis of rotation 105. The first core part 106b stationary unit 102 may be described to be positioned inside second core part 11 Of of the rotatable unit 104. The rotary transformer 100b in figures 3 and 4 may be described to be located inside a rotor shaft 840 of the rotor 810 of an electric rotating machine 800. The rotary transformer 100a in figure 2 may be described to be located outside the rotor shaft 840 of the rotor 810 of an electric rotating machine 800.

[0093] With reference to figures 2, 4 and 8A, for some embodiments, it may be defined that the two or more members 120a-f form position indicators (for example the entire member, or a corner or edge of the member) detectable, or sensed, by the one or more sensors 136a; 136b; 136c; 136d. For some embodiments, the sensor 136a; 136b; 136c; 136d may be referred to as a position sensor. The sensor 136a; 136b; 136c; 136d may be positioned at various possible locations. Sensors 136b, 136d illustrated by dotted lines in figures 2 and 4 may considered to illustrate alternative positions of the sensor. It is to be understood that one sensor 136a, 136c is sufficient for some embodiments. However, other embodiments may have two or more sensors. For some embodiments, the rotary transformer 100a; 100b may be described to comprise a rotary (or, angular) position detector 138a; 138b; 138c; 138c for detecting the rotary position of the rotatable unit 104, wherein the rotary position detector 138a; 138b comprises the two or more members 120a-f (see figure 8). For some embodiments, it may be defined that the rotary position detector 138a; 138b; 138c; 138c is configured to detect (and / or determine, and / or monitor) the rotary position (or, the rotational position, angular position, relative rotational position, position of rotation, or rotary displacement) of the rotatable unit 104 in relation to the stationary unit 102. For some embodiments, the rotary position detector 138a; 138b; 138c; 138c may comprise one or more sensors 136a; 136b; 136c; 136d configured to be immobile (or immovable, or stationary) in relation to the rotatable unit 104, wherein the sensor 136a; 136b; 136c; 136d is configured to detect one or more of the group of: the two or more members 120a-f; and position indicators formed by the two or more members 120a-f.

[0094] With reference to figures 2 and 4, for some embodiments, the one or more sensors 136a; 136b; 136c; 136d may comprise one or more of the group of:

[0095] • an inductive sensor;

[0096] • a capacitive sensor;

[0097] • a magnetic field sensor; a Hall-effect sensor; an optical sensor; and an ultrasonic sensor.

[0098] However, other sensors are also possible.

[0099] With reference to figure 5, schematic cross-section views of alternative structures of the stationary unit 102 (and / or of the first core part 106) and the rotatable unit 104 (and / or of the second core part 1 10) of embodiments of the rotary transformer according to the first aspect of the invention are illustrated in the illustrations a), b), c), d), e) and f). Each one of the stationary unit 102 and rotatable unit 104 may have windings and / or copper areas 108, 1 12, 1 13. Some embodiments may be provided with one or more polymer layers / coatings 115 or polymer composite layers / coatings 1 15. For additional embodiments, the core parts of the stationary unit 102 and of the rotatable unit 104 of each one of the illustrations a), b), c), d), e) and f) may interchanged.

[0100] With reference to figures 14 and 15, an embodiment of the electric rotating machine 800 according to the second aspect of the invention is schematically illustrated. The electric rotating machine 800 may act, or function, as an electric motor 804, for example for propelling a vehicle 900 (for example, see figure 17), such as an electric vehicle, EV, and / or as an electric generator 804, for example, for charging one or more electric battery arrangements 906 (see figure 17) and / or one or more electric battery packs.

[0101] With reference to figure 15, the electric rotating machine 800 includes a stator 806 and a rotor 810 rotatable about an axis of rotation 812 in relation to the stator 806. The electric rotating machine 800 includes a rotary transformer 100a according to any one of the embodiments disclosed above or below. The stator 806 may include one or more stator windings 808. It may be defined that the stator 806 is spaced from the rotor 810 to form a gap 814 between the stator 806 and the rotor 810. The rotor 810 may include one or more rotor windings (not shown in figure 15). However, for alternative embodiments, the electric rotating machine 800 may be configured for and operate according to other electrical operation schemes for electric rotating machines. For example, for alternative embodiments, the rotor may include one or more permanent magnets. Thus, the electric rotating machine may be a permanent magnet, PM, machine. Various conventional electric rotating machines and various conventional electrical operation schemes for conventional electric rotating machines are known to the skilled person and are thus not discussed herein in further detail.

[0102] With reference to figure 15, the electric rotating machine 800 may include a rotor compartment 816 holding the rotor 810. The electric rotating machine 800 may include a housing 818 which houses the stator 806 and the rotor 810. The housing 818 may define, or form, the rotor compartment 816. For some embodiments, the electric rotating machine 800 includes one or more gable units 820, 822 immovable in relation to the stator 806. For example, the rotor 810 may be connected, or attached, to the one or more gable units 820, 822 via one or more bearings 823.

[0103] With reference to figure 15, and as stated above, the electric rotating machine 800 includes a rotary transformer 100a according to any one of the embodiments disclosed above or below. The rotatable unit 104 of the rotary transformer 100a is positioned between the stationary unit 102 and the gable unit 820 to the right in figure 15. The stationary unit 102 of the rotary transformer 100a is positioned between the rotatable unit 104 and the gable unit 822 to the left in figure 15. However, it is to be understood that different embodiments of the rotary transformer may applied to the electric rotating machine 800 in several other ways and at other positions than what is illustrated in figure 15.

[0104] With reference to figure 16, the electric rotating machine 800 may include a fluid system 824 for cooling one or more of the rotor 810 and stator 806. The fluid of the fluid system 824 may comprise or consist of one or more of the group of: a liquid; a gas; and a gas mixture. The liquid may comprise or consist of an oil or an oil mixture. Thus, a fluid of the fluid system 824 may be an oil or an oil mixture. The fluid system 824 may be configured to cool one or more of the stationary unit 102 and rotatable unit 104 of the rotary transformer 10Oa-c. With reference to figure 15, the fluid system 824 may include one or more channels 826 for guiding a fluid, for example to and from the stator 806 and / or the rotor 810. The housing 818 may include, or form, the one or more channels 826. The fluid system 824 may include an inlet 828 for the inlet of fluid and an outlet 830 for the outlet of fluid. The inlet 828 and the outlet 830 may be an inlet 828 and outlet 830 of the housing 818. The inlet 828 may be an inlet 828 for the inlet of fluid to the one or more channels 826. The outlet 830 may be an outlet 830 for the outlet of fluid from the one or more channels 826.

[0105] With reference to figure 16, the fluid system 824 may include one or more conduits 832, or lines, for guiding a fluid, for example to or from the one or more channels 826 and / or the housing 818 of the electric rotating machine 800. The fluid system 824 may include a fluid collector and provider 834, for example a fluid collecting tray or vessel, or a fluid sump. For some embodiments, the fluid collector and provider 834 may be fluidly connected to the one or more channels 826 via a heat exchanger 836.

[0106] With reference to figure 17, an embodiment of the vehicle 900 according to the third aspect of the invention is schematically illustrated. The vehicle 900 includes one or more of the group of: a rotary transformer 100a-c according to any one of the embodiments disclosed above or below; and an electric rotating machine 800 according to any one of the embodiments disclosed above or below. The one or more electric rotating machines 800 may comprise one or more electric motors 802 and / or one or more electric generators 802. For example, the one or more electric rotating machines 800 may be configured for the propulsion of the vehicle 900. For example, one or more electric rotating machines 800 may be configured for charging one or more electrical battery arrangements 906 and / or one or more electric battery packs 910 of the vehicle 900. However, the electric rotating machine 800 may be used for other applications.

[0107] With reference to figure 17, the vehicle 900 is illustrated as a tractor vehicle. However, in other embodiments, the vehicle 900 may, for example, be a bus, a truck, a heavy truck or a car. Other types of vehicles are also possible. The vehicle 900 may be an electric vehicle, EV, for example a hybrid vehicle or a hybrid electric vehicle, HEV, or a battery electric vehicle, BEV.

[0108] With reference to figure 17, the vehicle 900 may be a wheeled vehicle, i.e. a vehicle 900 having wheels 902. Only the wheels 902 on the left-hand side of the vehicle 900 are visible in figure 17. It is to be understood that the vehicle 900 may have fewer or more wheels than what is shown in figure 17. The vehicle 900 may comprise a powertrain 904, for example configured for one of an EV, HEV and BEV. The vehicle 900 may be configured to hold or carry, or may include, one or more electrical battery arrangements 906 including two or more electric battery cells 908. The vehicle 900 may be configured to hold or carry, or may include, one or more electric battery packs 910 including two or more electric battery cells 908 and / or including two or more electrical battery arrangements 906, which may be referred to as modules. The electrical battery arrangement 906 and / or the electric battery pack 910 may, for example, be attachable to a chassis 912 of the vehicle 900. It is to be understood that the vehicle 900 may include further unites, components, such as electrical and / or mechanical components, a combustion engine 914 and other devices required for a vehicle 900, such as for an EV, HEV or BEV.

[0109] With reference to figure 17, it may be defined that the powertrain 904 and / or the one or more electric rotating machines 800 is / are configured to propel, or drive, the vehicle 900. It may be defined that the powertrain 904 includes the electrical battery arrangement 906 and / or the electric battery pack 910. The one or more electric rotating machines 800 may be located at locations different from what is illustrated in figure 17, for example in connection with the combustion engine 914, for example acting as an electric generator.

[0110] With reference to figure 17, the vehicle 900 may include a vehicle electrical system 916. It may be defined that the vehicle electrical system 916 is configured for direct current. It may be defined that vehicle electrical system 916 is a vehicle high voltage system 916. It may be defined that the vehicle high voltage system 916 is configured for a high voltage, such as a voltage above 60 V, for example above 400 V, or above 450 V, such as above 650 V. For example, the vehicle high voltage system 916 may be configured for a voltage up to 1500 V and / or for a voltage above 1500 V. The electric power, or the electric current, for example the direct current, of the vehicle electrical system 916 may be transferred at a high voltage, for example at one or more of the voltages levels mentioned above. The vehicle electrical system 916 may be configured to transfer the electric power, or the electric current, at a high voltage, for example at one or more of the voltages levels mentioned above. The vehicle electrical system 916 may be configured to transfer direct current.

[0111] With reference to Figure 17, the vehicle electrical system 916 may be electrically connected, or connectable, to one or more electrical battery arrangements 906 and / or one or more electric battery packs 910. It may be defined that the electrical battery arrangement 906 and / or the electric battery pack 910 is / are configured for high voltage, for example for one or more of the voltages levels mentioned above. The vehicle electrical system 916 may be configured to electrically connect the electrical battery arrangement 906 and / or the electric battery pack 910 to the powertrain 904 of the vehicle 900. The vehicle electrical system 916 may be configured to electrically connect the electrical battery arrangement 906 and / or the electric battery pack 910 to the one or more electric rotating machines 800 of the vehicle 900. It may be defined that the vehicle electrical system 916 is configured to transfer the electric power, or the electric current, for example between the one or more electric rotating machines 800 (and / or the powertrain 904) and the electrical battery arrangement 906 and / or the electric battery pack 910.

[0112] It is to be understood that embodiments of the rotary transformer 100a-c and the electric rotating machine 800 may be applied to configurations, structures, or apparatuses different from a vehicle 900, for example for charging electric batteries not located in a vehicle, or for a wind turbine generator (WTG) including an electric generator etc.

[0113] The present invention is not limited to the above-described embodiments. Instead, the present invention relates to, and encompasses all different embodiments being included within the scope of the independent claims.

Claims

Claims1. A rotary transformer (100a-c) for the transfer of electrical signals to a rotor (810) of an electric rotating machine (800), wherein the rotary transformer (100a-c) comprises a stationary unit (102), and a rotatable unit (104) rotatable about an axis of rotation (105) in relation to the stationary unit (102), wherein the stationary unit (102) comprises a first core part (106a-b) holding one or more primary windings (108) of the rotary transformer (100a-c), wherein the rotatable unit (104) comprises a second core part (1 10a-e) holding one or more secondary windings (1 12) of the rotary transformer (100a-c), wherein the second core part (1 10a-e) is annular and configured to surround and to rotate about the axis of rotation (105), wherein the second core part (110a-e) comprises two or more members (120a- f) spaced apart from one another in the direction of rotation ( / ?) of the second core part (1 10a-b) about the axis of rotation (105), and wherein the two or more members (120a-f) are detectable by one or more sensors (136a-d) so as to detect the rotary position of the rotatable unit (104).

2. A rotary transformer (100a-c) according to claim 1 , wherein the two or more members (120a-f) form position indicators detectable by the one or more sensors (136a-d).

3. A rotary transformer (100a-c) according to claim 1 or 2, wherein the rotary transformer (100a-c) comprises a rotary position detector (138a-d) for detecting the rotary position of the rotatable unit (104), and wherein the rotary position detector (138a-d) comprises the two or more members (120a-f).

4. A rotary transformer (100a-c) according to claim 3, wherein the rotary position detector (138a-d) is configured to detect the rotary position of the rotatable unit (104) in relation to the stationary unit (102).

5. A rotary transformer (100a-c) according to claim 3 or 4, wherein the rotary position detector (138a-d) comprises one or more sensors (136a-d) configured to be immobile in relation to the rotatable unit (104), and wherein the sensor (136a-d) is configured to detect one or more of the group of:• the two or more members (120a-f) ; and• position indicators formed by the two or more members (120a-f).

6. A rotary transformer (1 OOa-c) according to any one of the claims 1 to 5, wherein the one or more sensors (136a-d) comprises / comprise one or more of the group of:• an inductive sensor;• a capacitive sensor;• a magnetic field sensor;• a Hall-effect sensor;• an optical sensor; and• an ultrasonic sensor.

7. A rotary transformer (1 OOa-c) according to any one of the claims 1 to 6, wherein the two or more members (120a-f) are made of a ferromagnetic or ferrimagnetic material.

8. A rotary transformer (1 OOa-c) according to any one of the claims 1 to 7, wherein one or more of the first and second core parts (106a-b, 110a-e) is / are made of a ferromagnetic or ferrimagnetic material.

9. A rotary transformer (1 OOa-c) according to any one of the claims 1 to 8, wherein one or more of the second core part and members (120a-f) forms / form two or more recesses (122a-f), and wherein in the direction of rotation ( / ?) of the second core part (110a-e) about the axis of rotation (105) a recess (122a-f) of the two or more recesses (122a-f) ispositioned between every two members (120a-f) of the two or more members (120a- f)-10. A rotary transformer (100a-c) according to claim 9, wherein the two or more recesses (122a-f) are at least partly filled with one or more first materials (128) different from the material of one or more of the members (120a-f) and second core part (1 10a- e).1 1. A rotary transformer (1 OOa-c) according to claim 10, wherein the first material (128) comprises or consists of a polymer or a polymer composite.

12. A rotary transformer (1 OOa-c) according to any one of the claims 1 to 1 1 , wherein the second core part (1 10a-e) has a first side (114) facing the first core part (106a-b), wherein the second core part (1 10a-e) has one or more second sides (1 16) facing away from the first core part (106a-b), and wherein at the first side (114) of the second core part (1 10a-e) the second core part (1 10a-e) comprises a compartment (1 18) holding the one or more secondary windings (1 12).

13. A rotary transformer (1 OOa-c) according to claim 12, wherein at the second side (1 16) of the second core part (1 10a-e) the second core part (1 10a-e) comprises the two or more members (120a-f).

14. An electric rotating machine (800) comprising a stator (806), a rotor (810) rotatable about an axis of rotation (105) in relation to the stator (806), and a rotary transformer (1 OOa-c) according to any one of the claims 1 to 13,15. A vehicle (900) comprising one or more of the group of:• a rotary transformer (1 OOa-c) according to any one of the claims 1 to 13; and• an electric rotating machine (800) according to claim 14.

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