Temperature information output device and rotary electric machine

Abstract

To provide a temperature information output device capable of improving accuracy of temperature detection inside a rotary electric machine.SOLUTION: A temperature information output device includes a plurality of element units 50 provided in a rotor, an element unit 60 provided in a stator, and an output part. Each of the plurality of element units 50 includes a temperature sensing element 51 and a coil 53. The element unit 60 includes a coil 1 magnetically coupled to the coil 53 of each of the plurality of element units 50. The output part is electrically connected to the element unit 60. Resonance frequencies of the plurality of element units 50 in a state in which a first coil and a second coil are magnetically coupled are different from each other. The output part outputs an electric signal output from the element unit 60 as temperature information.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a temperature information output device and a rotating electric machine provided with the temperature information output device. [Background technology]

[0002] A temperature information output device is known that is provided in a rotating electric machine having a stator and a rotor and outputs temperature information related to the temperature of a portion of the rotor (see, for example, Patent Document 1). This temperature information output device includes a temperature-sensing element. The temperature-sensing element is provided in the rotor and its electrical resistance changes depending on the temperature of the portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-39019 Summary of the Invention [Problem to be solved by the invention]

[0004] The operation of a rotating electric machine may cause the temperature inside the rotating electric machine to rise. Temperature changes inside the rotating electric machine may affect the operation of the rotating electric machine. For example, the magnetic force of a magnet may change depending on the temperature of the magnet. Therefore, it may be possible to acquire temperature information about the rotating electric machine.

[0005] For example, in Patent Document 1, a temperature-sensing element and a first coil electrically connected to the temperature-sensing element are provided on a rotor. A second coil magnetically coupled to the first coil is provided on a stator, and an electrical signal corresponding to the magnitude of the current flowing through the second coil is output from an output unit. In such a configuration, if the temperature-sensing elements are arranged in multiple locations, the temperature inside the rotating electric machine can be detected more accurately. If the temperature inside the rotating electric machine is detected more accurately, the control accuracy of the rotating electric machine can also be improved. For example, if the temperature-sensing elements are arranged in multiple locations, the temperature of the magnets can also be controlled accurately.

[0006] It is an object of one aspect of the present invention to provide a temperature information output device that can easily ensure the accuracy of temperature information at multiple locations inside a rotating electrical machine. Another object of the present invention is to provide a rotating electrical machine that includes the above-mentioned temperature information output device. [Means for solving the problem]

[0007] A temperature information output device according to one aspect is provided in a rotating electric machine having a stator and a rotor, and outputs temperature information for the rotating electric machine. The temperature information output device includes a plurality of first element units provided in the rotor, a second element unit provided in the stator, and an output unit. Each of the plurality of first element units has a temperature-sensing element and a first coil. The temperature-sensing element changes electrical resistance depending on the temperature of the portion. The first coil is electrically connected to the temperature-sensing element. The second element unit has a second coil magnetically coupled to each of the first coils of the plurality of first element units. The output unit is electrically connected to the second element unit. When the first coil and the second coil are magnetically coupled, the resonance frequencies of the plurality of first element units are different from one another. The output unit outputs an electrical signal output from the second element unit as temperature information.

[0008] In one aspect, the temperature information output device includes a plurality of first element units provided on the rotor and a second element unit provided on the stator. The second element unit has a second coil magnetically coupled to each of the first coils of the plurality of first element units. In this case, the resonant frequencies of the plurality of first element units are different from each other when the first coil and the second coil are magnetically coupled, so that an electrical signal corresponding to each of the plurality of first element units is output from the second element unit. This allows temperature information to be output at multiple locations where the temperature-sensing elements of the plurality of first element units are respectively disposed. Therefore, the accuracy of temperature information at multiple locations inside a rotating electric machine, for example, can be easily ensured.

[0009] A temperature information output device according to another aspect is provided in a rotating electric machine having a stator and a rotor, and outputs temperature information related to the temperature of a portion of the rotor. The temperature information output device includes a plurality of first element units provided in the rotor, a plurality of second element units provided in the stator, and an output unit. Each of the plurality of first element units has a temperature-sensing element and a first coil. The temperature-sensing element changes electrical resistance depending on the temperature of the portion. The first coil is electrically connected to the temperature-sensing element. Each of the plurality of second element units has a second coil magnetically coupled to the first coil. The output unit is electrically connected to the second element unit. The plurality of first coils of the plurality of first element units and the plurality of second coils of the plurality of second element units form a plurality of pairs magnetically coupled to each other. The resonant frequencies of the plurality of first element units when the first coils and second coils forming corresponding pairs among the plurality of pairs are magnetically coupled are different from each other. The output unit outputs the electrical signal output from the second element unit as temperature information.

[0010] In another aspect of the present invention, the temperature information output device includes a plurality of first element units provided on a rotor and a plurality of second element units provided on a stator. Each of the plurality of second element units has a second coil magnetically coupled to a first coil of each of the plurality of first element units. In this case, the plurality of first element units have different oscillation frequencies when the first coil and the second coil forming a corresponding pair among the plurality of pairs are magnetically coupled. Therefore, an electrical signal corresponding to each of the plurality of first element units is output from a corresponding second element unit among the plurality of second element units. Therefore, temperature information can be output at multiple locations where the temperature sensors of the plurality of first element units are located when the first coil and the second coil forming a corresponding pair among the plurality of pairs are magnetically coupled. This makes it easy to ensure the accuracy of temperature information at multiple locations within the rotating electric machine.

[0011] A rotating electric machine according to yet another aspect includes the above-described temperature information output device, a stator, and a rotor. The rotor includes a magnet, a plurality of steel plates stacked in the rotational axis direction of the rotor, and a shaft extending in the rotational axis direction. The plurality of temperature-sensing elements included in the plurality of first element units include a first temperature-sensing element and a second temperature-sensing element that are different from each other. The first temperature-sensing element is provided on the magnet. The second temperature-sensing element is provided on the steel plate. In the above-described yet another aspect, the first temperature-sensing element is provided on the magnet, and the second temperature-sensing element is provided on the steel plate. Therefore, in the rotating electric machine, temperature information of the magnet and the steel plate can be easily output.

[0012] In another aspect of the present invention, the plurality of temperature sensing elements further includes a third temperature sensing element different from the first temperature sensing element and the second temperature sensing element. The third temperature sensing element is provided on the shaft. In this case, the third temperature sensing element is provided on the shaft. Therefore, in the rotating electric machine, temperature information of the magnet, the steel plate, and the shaft can be easily output. [Effects of the Invention]

[0013] According to one aspect of the present invention, there is provided a temperature information output device that can easily ensure the accuracy of temperature information at multiple locations inside a rotating electrical machine. In another aspect of the present invention, there is provided a rotating electrical machine that includes the temperature information output device described above. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a temperature information output device and a rotating electrical machine according to one embodiment. [Figure 2] FIG. 2 is a circuit diagram illustrating an example of a temperature information output device. [Figure 3] FIG. 3 is a partial perspective view of the rotating electric machine. [Figure 4] FIG. 4 is a diagram showing a cross-sectional configuration of the rotor core. [Figure 5] FIG. 5(a) is an end view of the stator and element unit, and FIG. 5(b) is an end view of the rotor and element unit. [Figure 6] FIG. 6 is a graph showing the frequency dependence of voltage for each temperature. [Figure 7] FIG. 7 is a graph showing the frequency dependency of voltage for each temperature. [Figure 8] FIG. 8 is a graph showing the frequency dependency of voltage for each temperature. [Figure 9] FIG. 9 is a graph showing the frequency dependency of voltage for each temperature. [Figure 10] FIG. 10 is a partial perspective view of a rotating electric machine according to a modified example of this embodiment. [Figure 11] FIG. 11(a) is an end view of a stator and an element unit according to a modified example of this embodiment, and FIG. 11(b) is an end view of a rotor and an element unit according to a modified example of this embodiment. [Figure 12] FIG. 12(a) is an end view of a stator and an element unit according to a modified example of this embodiment, and FIG. 12(b) is an end view of a rotor and an element unit according to a modified example of this embodiment. [Figure 13] FIG. 13(a) is a graph showing the frequency dependence of voltage at each temperature in a modified example of this embodiment, and FIG. 13(b) is a graph showing the frequency dependence of voltage at each temperature in a modified example of this embodiment. [Figure 14] FIG. 14(a) is a graph showing the frequency dependence of voltage at each temperature in a modified example of this embodiment, and FIG. 14(b) is a graph showing the frequency dependence of voltage at each temperature in a modified example of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same elements or elements having the same functions will be denoted by the same reference numerals, and redundant description will be omitted.

[0016] The configuration of a temperature information output device 1 according to this embodiment and a rotating electric machine MT provided with the temperature information output device 1 will be described with reference to Figures 1 to 5. Figure 1 is a schematic diagram showing the configuration of the temperature information output device and rotating electric machine according to this embodiment.

[0017] As shown in FIG. 1, the temperature information output device 1 is provided in a rotating electric machine MT. The rotating electric machine MT is, for example, a motor. The motor includes, for example, an IPM motor or an SPM motor. The motor may be a wound-field motor. Unless otherwise specified, the following description will be given of an example in which the rotating electric machine MT is an IPM motor. As shown in FIG. 1, the rotating electric machine MT includes a stator 10 and a rotor 20. The rotor 20 is located inside the stator 10.

[0018] The rotor 20 includes a shaft 21, a rotor core 23, and a plurality of magnets 25. The shaft 21 has a cylindrical shape. The rotor core 23 has a cylindrical shape. An axial hole into which the shaft 21 is fitted is formed in the rotor core 23. The shaft 21 and the rotor core 23 rotate together around the central axis of the shaft 21.

[0019] Each magnet 25 is arranged in the rotor core 23 so that its extension direction is parallel to the central axis of the shaft 21. "The extension direction of the magnet 25 is parallel to the central axis of the shaft 21" does not necessarily mean that the extension direction of the magnet 25 is parallel to the central axis of the shaft 21. The extension direction of the magnet 25 may be considered parallel to the central axis of the shaft 21 even if there is a slight difference within a preset range, a manufacturing error, or a measurement error. If there is a slight difference within a preset range, for example, if the angle between the extension direction of the magnet 25 and the central axis of the shaft 21 is within a range of ±2 degrees, the extension direction of the magnet 25 may be considered parallel to the central axis of the shaft 21.

[0020] The central axis of the shaft 21 is the rotation axis of the rotor 20. The direction in which the rotation axis of the rotor 20 extends is the rotation axis direction D of the rotor 20. One magnet may constitute one pole, or multiple magnets may constitute one pole. When one magnet constitutes one pole, the multiple magnets 25 are arranged at equal angular intervals with respect to the rotation axis of the rotor 20. "Even angular intervals" does not necessarily mean that the angular intervals are the same. The angular intervals may be considered equal even if there are slight differences within a predetermined range, manufacturing errors, or measurement errors. If there are slight differences within a predetermined range, for example, if each angular interval of the magnets 25 with respect to the rotation axis of the rotor 20 is within a range of ±10% of the average angular interval of all angular intervals, the angular intervals of the magnets 25 with respect to the rotation axis of the rotor 20 may be considered equal.

[0021] When the rotating electric machine MT is an IPM motor, the multiple magnets 25 are arranged inside the rotor core 23. When the rotating electric machine MT is an SPM motor, the multiple magnets 25 are arranged on the surface of the rotor core 23. The magnets 25 are, for example, permanent magnets. The magnets 25 include rare earth magnets. The magnets 25 include, for example, neodymium sintered magnets. Each magnet 25 may include a sintered magnet other than a rare earth magnet, or may include a magnet other than a sintered magnet. The magnet other than a sintered magnet includes, for example, a bonded magnet or a hot-worked magnet.

[0022] The stator 10 includes a cylindrical stator core (not shown) that surrounds the outer periphery of the rotor 20, and multiple stator coils 11. The stator 10 may further include a case that surrounds the stator core, the multiple stator coils 11, and the rotor 20. An air gap of uniform width is provided between the stator 10 and the rotor 20. "Uniform width" does not necessarily mean that the widths of the air gaps between the stator 10 and the rotor 20 are uniform. The widths of the air gaps between the stator 10 and the rotor 20 may be considered uniform even if slight differences within a predetermined range, manufacturing errors, or measurement errors are included. If slight differences within a predetermined range are included, for example, if the widths of the air gaps between the stator 10 and the rotor 20 are within a range of ±10% of the average width of all the air gaps, the widths of the air gaps between the stator 10 and the rotor 20 may be considered uniform. The stator core holds the multiple stator coils 11. Each stator coil 11 is disposed on the inner periphery of the stator core. The plurality of stator coils 11 are disposed at equal angular intervals with respect to the rotation axis of the rotor 20.

[0023] The rotating electric machine MT is connected to a control circuit 41. The control circuit 41 is connected to a power source 43. The control circuit 41 adjusts the drive current from the power source 43 and supplies three-phase AC current to each stator coil 11. The control circuit 41 controls the value of the three-phase AC current supplied to each stator coil 11. The control circuit 41 includes, for example, an inverter circuit. When the three-phase AC current is supplied to each stator coil 11, each stator coil 11 forms a rotating magnetic field that rotates the rotor 20. The power source 43 includes, for example, an electric energy storage device. The electric energy storage device includes, for example, a secondary battery or a capacitor.

[0024] Next, the configuration of the temperature information output device 1 will be described in more detail with reference to Fig. 2 to Fig. 4. Fig. 2 is a circuit diagram showing an example of a temperature information output device. Fig. 3 is a partial perspective view of a rotating electric machine. Fig. 4 is a diagram showing a cross-sectional configuration of a rotor core.

[0025] The temperature information output device 1 outputs temperature information related to the temperature inside the rotating electric machine MT. The temperature information output device 1 outputs temperature information related to the temperature of a portion of the rotor 20. To realize this function, the temperature information output device 1 includes a plurality of element units 50, an element unit 60, an electric resistance element 70, and an output section 80. In this embodiment, the number of element units 60 is one. The plurality of element units 50 are provided on the rotor 20. The element unit 60 is provided on the stator 10. The element unit 60 is provided on, for example, a stator core.

[0026] The plurality of element units 50 and element units 60 are arranged to face each other in a direction parallel to the rotation axis of the rotor 20 when the rotor 20 is at a predetermined rotation angle position. The "direction parallel to the rotation axis of the rotor 20" does not necessarily mean only a direction parallel to the rotation axis of the rotor 20. Even if slight differences, manufacturing errors, or measurement errors within a preset range are included, the direction may be considered to be parallel to the rotation axis of the rotor 20. If slight differences within a preset range are included, for example, a direction whose angle with the rotation axis of the rotor 20 is within a range of ±2 degrees may be considered to be parallel to the rotation axis of the rotor 20.

[0027] 2, each of the plurality of element units 50 has a temperature sensor 51, a coil 53, and a capacitor 55. The temperature sensor 51, the coil 53, and the capacitor 55 of each element unit 50 are provided on the rotor 20. When the coil 53 is magnetically coupled to a coil 61 described later, the plurality of element units 50 have different resonant frequencies.

[0028] The rotor core 23 includes a pair of end faces 23a, 23b and one side face. The end face 23a is located closer to the element unit 60. That is, the end face 23a is located closer to the coil 61. The end face 23b is located on the opposite side of the end face 23a in the rotational axis direction D. That is, the pair of end faces 23a, 23b are perpendicular to the rotational axis direction D and face in opposite directions. The phrase "the pair of end faces 23a, 23b are perpendicular to the rotational axis direction D" does not necessarily mean that the pair of end faces 23a, 23b are perpendicular to the rotational axis direction D. It is also acceptable to say that the pair of end faces 23a, 23b are perpendicular to the rotational axis direction D even when slight differences, manufacturing errors, or measurement errors within a preset range are included. If there is a slight difference within a preset range, for example, if the angle between the pair of end faces 23a, 23b and the rotation axis direction D is within a range of ±1 degree from perpendicular, the pair of end faces 23a, 23b may be considered to be perpendicular to the rotation axis direction D.

[0029] As shown in FIG. 4 , the rotor core 23 is configured by stacking a plurality of steel plates M1 in the rotational axis direction D. The rotor core 23 includes a plurality of steel plates M1 stacked in the rotational axis direction D. The steel plates M1 are magnetic. The steel plates M1 may be, for example, silicon steel plates. In this embodiment, of the plurality of steel plates M1, the steel plate M1 located closest to the coil 61 includes an end face 23a as its surface.

[0030] The magnet 25 is disposed in the rotor core 23. In this embodiment, as shown in FIG. 4, the entire magnet 25 is disposed within the rotor core 23. The magnet 25 has a pair of faces 25a, 25b and four side faces. The face 25a is located closer to the coil 61. The face 25b is located on the opposite side of the face 25a in the rotational axis direction D. That is, the pair of faces 25a, 25b are perpendicular to the rotational axis direction D and face in opposite directions. The phrase "the pair of faces 25a, 25b are perpendicular to the rotational axis direction D" does not necessarily mean that the pair of faces 25a, 25b are perpendicular to the rotational axis direction D. It is also possible to say that the pair of faces 25a, 25b are perpendicular to the rotational axis direction D even when slight differences, manufacturing errors, or measurement errors within a predetermined range are included. If there is a slight difference within a preset range, for example, if the angle between the pair of surfaces 25a, 25b and the rotation axis direction D is within a range of ±2 degrees from perpendicular, the pair of surfaces 25a, 25b may be considered to be perpendicular to the rotation axis direction D.

[0031] Like the magnet 25, the coil 53 is also arranged within the rotor core 23. In this embodiment, at least a portion of the coil 53 is arranged within the rotor core 23. The coil 53 is arranged within the rotor core 23 closer to the end face 23a than the magnet 25. One end 54 of the coil 53 in the rotation axis direction D is exposed from the rotor core 23. The one end 54 is exposed at the end face 23a of the rotor core 23. In this embodiment, only the one end 54 of the coil 53 is exposed from the rotor core 23, and the rest of the coil 53 is embedded in the rotor core 23. As shown in FIG. 4, in this embodiment, the end face 23a is flush with the one end 54 of the coil 53. "End surface 23a is flush with one end 54" means that, in addition to end surface 23a being flush with one end 54, there is also included a step between end surface 23a and one end 54, the step being, for example, 1% or less of the length in the rotation axis direction D of rotor 20. At least a portion of coil 53 needs to be disposed within rotor core 23, and a portion other than one end 54 may be exposed from rotor core 23. In this case, for example, a portion of the side of coil 53 that is located closer to one end 54 may be exposed from rotor core 23, and end surface 23a does not need to be flush with one end 54.

[0032] The temperature sensing element 51 is provided at a predetermined location on the rotor 20. In the temperature sensing element 51, the electrical resistance changes depending on the temperature of the location. In the temperature sensing element 51, the electrical resistance decreases as the temperature increases. The temperature sensing element 51 may be, for example, a thermistor or a Hall element. The thermistor may be, for example, an NTC thermistor. The coil 53 is electrically connected to the temperature sensing element 51. In this embodiment, both ends of the coil 53 are electrically connected to both ends of the temperature sensing element 51. The capacitor 55 and the coil 53 form an LC resonant circuit. The capacitor 55 is inserted so as to be connected in parallel with the coil 53, for example.

[0033] In this embodiment, the plurality of element units 50 have temperature sensing elements 51a, 51b, and 51c as the temperature sensing element 51. The plurality of element units 50 have coils 53a, 53b, and 53c as the coils 53. For example, the plurality of coils 53a, 53b, and 53c have different inductance values. In the plurality of element units 50 having the plurality of coils 53a, 53b, and 53c, the resonant frequencies of the plurality of element units 50 in a state in which the coils 53 are magnetically coupled to a coil 61 (described later) are different from one another.

[0034] As a modification of this embodiment, for example, the inductance values ​​of the coils 53 a, 53 b, and 53 c may be the same. In this case, the capacitances of the capacitors 55 of the element units 50 are different from one another, and the resonant frequencies of the element units 50 when the coil 53 is magnetically coupled to a coil 61 (described later) are different from one another.

[0035] The temperature information output device 1 includes an element unit 50 having a temperature sensing element 51a and a coil 53a, an element unit 50 having a temperature sensing element 51b and a coil 53b, and an element unit 50 having a temperature sensing element 51c and a coil 53c. Both ends of the coil 53a are electrically connected to both ends of the temperature sensing element 51a. Both ends of the coil 53b are electrically connected to both ends of the temperature sensing element 51b. Both ends of the coil 53c are electrically connected to both ends of the temperature sensing element 51c.

[0036] The temperature sensor 51 is provided on at least one of the magnets 25. In this embodiment, the temperature sensor 51a is provided on the magnet 25, the temperature sensor 51b is provided on the steel plate M1, and the temperature sensor 51c is provided on the shaft 21. The temperature sensor 51a is arranged so as to be in contact with the magnet 25. The temperature sensor 51a may be arranged near the magnet 25. The electrical resistance of the temperature sensor 51a changes in accordance with the temperature of the magnet 25. The temperature sensor 51b is arranged so as to be in contact with the steel plate M1. The temperature sensor 51b may be arranged near the steel plate M1. The electrical resistance of the temperature sensor 51b changes in accordance with the temperature of the steel plate M1. The temperature sensor 51c is arranged so as to be in contact with the shaft 21. The temperature sensor 51c may be arranged near the shaft 21. The electrical resistance of the temperature sensor 51c changes in accordance with the temperature of the shaft 21.

[0037] The element unit 60 has a coil 61 and a capacitor 63. The coil 61 is arranged on the stator 10 so as to face the coil 53 in the rotational axis direction D of the rotor 20 when the rotor 20 is at a predetermined rotation angle position. The coils 53a, 53b, 53c and the coil 61 are arranged so as to face each other in the rotational axis direction D of the rotor 20 when the rotor 20 is at a predetermined rotation angle.

[0038] The coil 61 is magnetically coupled to each of the coils 53a, 53b, and 53c. The coil 61 is electrically connected to an AC power supply PS. The AC power supply PS may be, for example, an inverter. An AC signal of a predetermined frequency is applied to the coil 61 from the AC power supply PS. An AC voltage is applied to the coil 61 from the AC power supply PS. The predetermined frequency is higher than the drive frequency of the rotating electric machine MT. The predetermined frequency is, for example, 10 to 2000 times the drive frequency of the rotating electric machine MT.

[0039] For example, as shown in FIGS. 5(a) and 5(b), coils 53a, 53b, and 53c are arranged at different positions from one another when viewed from the rotational axis direction D. Coils 53a, 53b, and 53c are arranged on the same circular center centered on shaft 21 when viewed from the rotational axis direction D. In other words, coils 53a, 53b, and 53c are arranged so as to overlap with circumference C2. For example, when viewed from the rotational axis direction D, the centers of coils 53a, 53b, and 53c are arranged on the same circular center centered on shaft 21. In other words, the centers of coils 53a, 53b, and 53c are arranged so as to overlap with circumference C2. Coil 61 is arranged so as to overlap with circumference C1, which overlaps with circumference C2 when viewed from the rotational axis direction D. For example, the center of coil 61 is arranged so as to overlap with circumference C1.

[0040] The capacitor 63 forms an LC resonant circuit together with the coil 61. The capacitor 63 may form an LC resonant circuit together with the coil 53 and the coil 61. The capacitor 63 is inserted, for example, so as to be connected in parallel to the coil 61. For example, when the coil 53 forms a first coil, the coil 61 forms a second coil.

[0041] A magnetic flux corresponding to the AC voltage applied from the AC power supply PS is generated in the coil 61. When the rotor 20 rotates and the coil 61 and the coil 53 approach each other, the magnetic flux generated in the coil 61 passes through the coil 53. When the magnetic flux generated in the coil 61 passes through the coil 53, power corresponding to the change in the magnetic flux passing through the coil 53 is generated in the coil 53. In other words, when the rotor 20 rotates and the coil 61 and the coil 53 approach each other, the coil 61 and the coil 53 are magnetically coupled. Alternatively, it can be said that the coil 61 excites the coil 53 and supplies power to the coil 53.

[0042] If the electrical resistance of the temperature sensing element 51 changes in accordance with the temperature inside the rotating electric machine MT, the magnetic flux generated in the coil 61 changes in accordance with the change in the electrical resistance of the temperature sensing element 51. For example, the electrical resistance of the temperature sensing element 51a changes in accordance with the temperature of the magnet 25. The current flowing through the coil 61 changes in accordance with the change in the magnetic flux generated in the coil 61. In this embodiment, the magnitude of the voltage drop generated in the electrical resistance element 70 changes as the current flowing through the coil 61 changes.

[0043] When the temperature inside the rotating electric machine MT rises and the electrical resistance of the temperature sensing element 51 decreases, the magnetic flux generated in the coil 61 increases. As a result, the current flowing through the coil 61 increases. When the temperature inside the rotating electric machine MT falls and the electrical resistance of the temperature sensing element 51 increases, the magnetic flux generated in the coil 61 decreases. As a result, the current flowing through the coil 61 decreases.

[0044] The electric resistance element 70 is electrically connected to the element unit 60. The electric resistance element 70 may be electrically connected to the coil 61. In this embodiment, the electric resistance element 70 is provided on the stator 10 and inserted between the coil 61 and the AC power supply PS. The electric resistance element 70 may be an internal resistance of the output unit 80. The range of electric resistance of the electric resistance element 70, which clearly detects changes in the temperature inside the rotating electric machine MT, also changes in accordance with changes in the electric resistance of the temperature sensing element 51. In this embodiment, the electric resistance of the electric resistance element 70 is set to a range that clearly detects changes in the temperature inside the rotating electric machine MT. In addition to the preferred range of the electric resistance of the electric resistance element 70, the impedance of the entire temperature information output device 1, including the element unit 50 and the element unit 60, also changes in accordance with changes in the electric resistance of the temperature sensing element 51. In other words, the composite impedance of the element unit 50 and the element unit 60 also changes in accordance with changes in the electric resistance of the temperature sensing element 51.

[0045] In this embodiment, as the current flowing through the coil 61 increases, the magnitude of the voltage drop occurring across the electrical resistance element 70 also increases. As the current flowing through the coil 61 decreases, the magnitude of the voltage drop occurring across the electrical resistance element 70 also decreases. That is, as the temperature of the temperature sensing element 51 increases, the magnitude of the voltage drop occurring across the electrical resistance element 70 increases. Similarly, as the temperature of the temperature sensing element 51 decreases, the magnitude of the voltage drop occurring across the electrical resistance element 70 decreases.

[0046] The output unit 80 is electrically connected to the element unit 60. The output unit 80 may be electrically connected to the coil 61. The coil 61 may be electrically connected to the capacitor 63 and the output unit 80. In this embodiment, the output unit 80 is electrically connected to the electrical resistance element 70. The output unit 80 is provided on the stator 10.

[0047] The output unit 80 outputs an electrical signal related to the phase of the power generated in the coil 61 as temperature information. In this embodiment, the output unit 80 outputs an electrical signal corresponding to the magnitude of the voltage drop generated in the electrical resistance element 70. The output unit 80 may output an electrical signal indicating the magnitude of the voltage drop generated in the electrical resistance element 70. The output unit 80 includes, for example, a voltmeter. The voltmeter may be configured with a computing device including, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The computing device may be, for example, a microcomputer. In this case, the voltmeter loads a program stored in the ROM into the RAM and executes the program on the CPU, thereby outputting the electrical signal corresponding to the magnitude of the voltage drop generated in the electrical resistance element 70.

[0048] In this embodiment, the output unit 80 detects the magnetic flux generated in the coil 61 as the magnitude of the voltage drop occurring in the electrical resistance element 70. The magnitude of the voltage drop detected by the output unit 80 corresponds to a change in the electrical resistance of the temperature sensing element 51, i.e., a change in the temperature inside the rotating electrical machine MT. Therefore, the electrical signal output from the output unit 80 includes temperature information related to the temperature inside the rotating electrical machine MT. In other words, the output unit 80 outputs an electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70 as the temperature information. As a result, temperature information related to the temperature inside the rotating electrical machine MT is wirelessly transmitted between the element unit 50 and the output unit 80 via the element unit 60.

[0049] As a modification of this embodiment, the output unit 80 may include, for example, a phase detector that detects the phase of the input signal instead of or in addition to a voltmeter. This phase detector may be, for example, an integrated circuit (IC) or an oscilloscope. The output unit 80 outputs the phase difference between the phase of the voltage applied to the element unit 60 and the phase of the voltage at the output unit 80 as temperature information. For example, the output unit 80 detects the phase difference between the phase of the voltage applied to the coil 61 by the AC power supply PS and the phase of the voltage at the coil 61, and outputs the detected phase difference as temperature information.

[0050] The phase difference detected by the output unit 80 corresponds to a change in the electrical resistance of the temperature-sensing element 51, i.e., a change in the temperature inside the rotating electric machine MT. Therefore, the electrical signal output from the output unit 80 includes temperature information related to the temperature inside the rotating electric machine MT. The output unit 80 outputs the detected phase difference as an electrical signal indicating the temperature information. As a result, temperature information related to the temperature inside the rotating electric machine MT is transmitted wirelessly between the element unit 50 and the output unit 80 via the element unit 60.

[0051] An example of an electrical signal detected by the output section 80 will be described using Fig. 6. Fig. 6 is a graph showing the frequency dependency of voltage for each temperature. The vertical axis represents the voltage detected by the output section 80, and the horizontal axis represents the frequency of the voltage applied by the AC power supply PS. Data D1 to D5 represent data output from the output section 80 when the element unit 60 has an electrical resistance element 70 that is different from the internal resistance of the output section 80.

[0052] The data D1 to D5 each represent data relating to a different element unit 50. In other words, the data D1 to D5 each correspond to the coil 53 of a different element unit 50, and represent a change in the temperature sensing element 51 of each element unit 50 in response to a change in the temperature inside the rotating electric machine MT.

[0053] The capacitance of capacitor 55 is the same for all of data D11 to D15. The capacitance of capacitor 63 is the same for all of data D11 to D15. The inductance value of coil 61 is 30 μH for all of data D1 to D5.

[0054] In data D1, the inductor value of coil 53 is 60 μH. In data D2, the inductor value of coil 53 is 50 μH. In data D3, the inductor value of coil 53 is 40 μH. In data D4, the inductor value of coil 53 is 30 μH. In data D5, the inductor value of coil 53 is 20 μH. As shown in FIG. 6, it was confirmed that the output unit 80 outputs an electrical signal in a state where the changes in electrical resistance of the temperature sensing elements 51 in the multiple element units 50 can be identified, that is, in a state where the temperature information of multiple locations inside the rotating electric machine MT can be identified.

[0055] Next, an example of an electrical signal detected by the output unit 80 in a modified example of this embodiment will be described with reference to Fig. 7. Fig. 7 is a graph showing the frequency dependency of voltage for each temperature. The vertical axis represents the voltage detected by the output unit 80, and the horizontal axis represents the frequency of the voltage applied by the AC power supply PS. Data D11 to D15 represent data output from the output unit 80 when the output unit 80 does not have an electrical resistance element 70 in addition to the internal resistance.

[0056] The data D11 to D15 each represent data relating to a different element unit 50. In other words, the data D11 to D15 each correspond to the coils 53 of the different element units 50, and represent changes in the temperature sensing elements 51 of the element units 50 in response to changes in the temperature inside the rotating electric machine MT.

[0057] In all of the data D11 to D15, the capacitance of the capacitor 55 is the same. In all of the data D11 to D15, the capacitance of the capacitor 63 is the same. In all of the data D11 to D15, the inductance value of the coil 61 is 30 μH.

[0058] In data D11, the inductor value of coil 53 is 60 μH. In data D12, the inductor value of coil 53 is 50 μH. In data D13, the inductor value of coil 53 is 40 μH. In data D14, the inductor value of coil 53 is 30 μH. In data D15, the inductor value of coil 53 is 20 μH. As shown in FIG. 7, even when output unit 80 does not have an electrical resistance element 70 in addition to the internal resistance, it was confirmed that output unit 80 outputs an electrical signal in a state in which temperature information from multiple locations inside rotating electric machine MT can be individually identified.

[0059] Next, an example of an electrical signal detected by the output unit 80 in a modified example of this embodiment will be described with reference to Figs. 8 and 9. Figs. 8 and 9 are graphs showing the frequency dependence of voltage for each temperature. The vertical axis represents the voltage detected by the output unit 80, and the horizontal axis represents the frequency of the voltage applied by the AC power supply PS. Data D21 to D24 represent data output from the output unit 80 that has the electrical resistance element 70. Data D31 to D34 represent data output from the output unit 80 when the output unit 80 does not have the electrical resistance element 70.

[0060] The data D21 to D24 each represent data relating to a different element unit 50. In other words, the data D21 to D24 each correspond to the coils 53 of different element units 50, and represent changes in the temperature sensing elements 51 of the element units 50 in response to changes in the temperature inside the rotating electric machine MT. Similarly, the data D31 to D34 each represent data relating to a different element unit 50. In other words, the data D31 to D34 each correspond to the coils 53 of different element units 50, and represent changes in the temperature sensing elements 51 of the element units 50 in response to changes in the temperature inside the rotating electric machine MT.

[0061] The inductance value of the coil 53 is the same for all of the data D21 to D24 and data D31 to D34. The inductance value of the coil 61 is the same for all of the data D21 to D24 and data D31 to D34. The capacitance of the capacitor 63 is 4.7 nF for all of the data D21 to D24 and data D31 to D34.

[0062] In data D21, the capacitance of capacitor 55 is 10 nF. In data D22, the capacitance of capacitor 55 is 7 nF. In data D23, the capacitance of capacitor 55 is 4.7 nF. In data D24, the capacitance of capacitor 55 is 1.5 nF. As shown in FIG. 8, it was confirmed that the output unit 80 outputs an electrical signal in a state where the changes in the electrical resistance of the temperature sensing elements 51 in the multiple element units 50 can be identified, that is, in a state where the temperature information of multiple locations inside the rotating electric machine MT can be identified.

[0063] In data D31, the capacitance of capacitor 55 is 15 nF. In data D32, the capacitance of capacitor 55 is 10 nF. In data D33, the capacitance of capacitor 55 is 7 nF. In data D34, the capacitance of capacitor 55 is 4.7 nF. As shown in FIG. 9, even when output unit 80 does not have electrical resistance element 70, it was confirmed that output unit 80 outputs an electrical signal in a state in which temperature information at multiple locations inside rotating electric machine MT can be individually identified.

[0064] The electrical signal output from the output unit 80 is input to the control circuit 41 as the temperature information. The control circuit 41 acquires the electrical signal output from the temperature information output device 1. The control circuit 41 acquires the temperature inside the rotating electric machine MT based on the acquired electrical signal. That is, in this embodiment, the control circuit 41 functions as a temperature acquisition device.

[0065] The control circuit 41 obtains the temperature inside the rotating electric machine MT, for example, as follows. First, the control circuit 41 refers to data indicating the relationship between the temperature and an electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. The data may be stored in the control circuit 41, or may be stored in an external server different from the control circuit 41. Next, the control circuit 41 obtains the temperature corresponding to the acquired electrical signal from the above data as the temperature inside the rotating electric machine MT.

[0066] The control circuit 41 controls the driving state of the rotating electric machine MT based on the obtained internal temperature of the rotating electric machine MT. For example, the control circuit 41 controls the driving state of the rotating electric machine MT as follows: When the control circuit 41 determines that the obtained internal temperature of the rotating electric machine MT has risen to a predetermined first threshold, the control circuit 41 controls the supply power to limit the rotational speed of the rotating electric machine MT. When the control circuit 41 determines that the obtained internal temperature of the rotating electric machine MT has dropped to a predetermined second threshold that is smaller than the first threshold, the control circuit 41 controls the supply power to release the limit on the rotational speed of the rotating electric machine MT.

[0067] The control circuit 41 may control the drive state of the rotating electric machine MT as follows. That is, the control circuit 41 may control, for example, the drive frequency input to the rotating electric machine MT based on the obtained internal temperature of the rotating electric machine MT. When the control circuit 41 determines that the obtained internal temperature of the rotating electric machine MT has risen to a predetermined first threshold, the control circuit 41 controls the drive frequency to decrease so as to limit the rotation speed of the rotating electric machine MT. When the control circuit 41 determines that the obtained internal temperature of the rotating electric machine MT has dropped to a predetermined second threshold that is smaller than the first threshold, the control circuit 41 controls the drive frequency to increase so as to remove the limit on the rotation speed of the rotating electric machine MT.

[0068] The control circuit 41 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The control circuit 41 obtains the temperature inside the rotating electric machine MT and controls the driving state of the rotating electric machine MT, for example, by loading a program stored in the ROM into the RAM and executing the program with the CPU.

[0069] Next, the configuration of a modified example of the rotating electric machine MT will be described with reference to Fig. 10, Fig. 11(a), and Fig. 11(b). This modified example differs from the above-described embodiment in that a plurality of element units 60 is provided. Below, the differences between the above-described embodiment and this modified example will be mainly described. Fig. 10 is a partial perspective view of a rotating electric machine of a modified example of this embodiment. Fig. 11(a) is an end view of a stator and element units of the modified example of this embodiment, and Fig. 11(b) is an end view of a rotor and element units of the modified example of this embodiment.

[0070] In this modified example, the temperature information output device 1 includes a plurality of element units 60. The plurality of element units 60 are provided on the stator 10. The plurality of element units 60 are provided on, for example, a stator core. The plurality of element units 50 and the plurality of element units 60 form a plurality of pairs that are magnetically coupled to each other.

[0071] The plurality of element units 50 and the plurality of element units 60 are arranged to face each other in a direction parallel to the rotation axis of the rotor 20 when the rotor 20 is at a predetermined rotation angle position. The "direction parallel to the rotation axis of the rotor 20" does not necessarily mean only a direction parallel to the rotation axis of the rotor 20. Even if slight differences, manufacturing errors, or measurement errors within a preset range are included, the direction may be considered to be parallel to the rotation axis of the rotor 20. If slight differences within a preset range are included, for example, a direction whose angle with the rotation axis of the rotor 20 is within a range of ±2 degrees may be considered to be parallel to the rotation axis of the rotor 20.

[0072] In this modified example, the plurality of element units 50 have temperature sensing elements 51a and 51b as the temperature sensing element 51. The plurality of element units 50 have coils 53a and 53b as the coils 53. The temperature information output device 1 includes an element unit 50 having a temperature sensing element 51a and a coil 53a, and an element unit 50 having a temperature sensing element 51b and a coil 53b. Both ends of the coil 53a are electrically connected to both ends of the temperature sensing element 51a. Both ends of the coil 53b are electrically connected to both ends of the temperature sensing element 51b. For example, the inductance values ​​of the plurality of coils 53a and 53b are different from each other.

[0073] Each of the plurality of element units 60 has a coil 61 and a capacitor 63. The plurality of element units 60 has coils 61a and 61b as the coils 61. The coils 61a and 61b are arranged on the stator 10 so as to face the coils 53a and 53b in the rotational axis direction D of the rotor 20 when the rotor 20 is at a predetermined rotation angle position. The coils 53a and 61a are arranged so as to face each other in the rotational axis direction D of the rotor 20 when the rotor 20 is at a predetermined rotation angle. The coils 53b and 61b are arranged so as to face each other in the rotational axis direction D of the rotor 20 when the rotor 20 is at a predetermined rotation angle. The coil 61a is magnetically coupled to the coil 53a. The coil 61b is magnetically coupled to the coil 53b. That is, the plurality of coils 53 and the plurality of coils 61 form a plurality of pairs that are magnetically coupled to each other.

[0074] For example, the inductance value of coil 61a, which is paired with coil 53a, is different from the inductance value of coil 53b, but is the same as the inductance value of coil 53a. The element unit 50 having coil 53a and the element unit 60 having coil 61a have the same resonance frequency. The inductance value of coil 61b, which is paired with coil 53b, is different from the inductance value of coil 53a, but is the same as the inductance value of coil 53b. The element unit 50 having coil 53b and the element unit 60 having coil 61b have the same resonance frequency. In other words, the inductance values ​​of the coils that are paired with each other are the same, and the resonance frequencies of the element units 50 and 60 that are paired with each other are the same.

[0075] In this modification, the resonant frequencies of the plurality of element units 50 are different when the coils 53 and 61 that form corresponding pairs among the plurality of pairs of the coils 53 and 61 are magnetically coupled. In other words, the resonant frequency of the element unit 50 that has the coil 53a when the coils 53a and 61a are magnetically coupled is different from the resonant frequency of the element unit 50 that has the coil 53b when the coils 53b and 61b are magnetically coupled.

[0076] As a further modification of this modification, the inductance values ​​of the multiple coils 53 a, 53 b may be the same. In this case, the capacitances of the capacitors 55 of the multiple element units 50 are different from each other. The resonant frequencies of the multiple element units 50 are different from each other when the coils 53 and 61 that form corresponding pairs among the multiple pairs of the coils 53 and 61 are magnetically coupled.

[0077] For example, as shown in Figures 11(a) and 11(b), when viewed from the rotation axis direction D, the coils 53a and 53b are arranged at different positions from each other. When viewed from the rotation axis direction D, the coils 53a and 53b are arranged on the same circular center about the shaft 21. In other words, the coils 53a and 53b are arranged so as to overlap with the circumference C2. When viewed from the rotation axis direction D, for example, the centers of the coils 53a and 53b are arranged on the same circular center about the shaft 21. In other words, the centers of the coils 53a and 53b are arranged so as to overlap with the circumference C2.

[0078] When viewed from the rotation axis direction D, the coils 61a and 61b are arranged at different positions from each other. When viewed from the rotation axis direction D, the coils 61a and 61b are arranged on the same circular core with the shaft 21 as the center. In other words, the coils 61a and 61b are arranged so as to overlap with the circumference C1. For example, when viewed from the rotation axis direction D, the centers of the coils 61a and 61b are arranged on the same circular core with the shaft 21 as the center. In other words, the centers of the coils 61a and 61b are arranged so as to overlap with the circumference C2. When viewed from the rotation axis direction D, the coils 61a and 61b are arranged so as to overlap with the circumference C1, which overlaps with the circumference C2. For example, the centers of the coils 61a and 61b are arranged so as to overlap with the circumference C1.

[0079] Next, the configuration of a modified example of the rotating electric machine MT will be described with reference to Figs. 12(a) and 12(b). This modified example differs from the modified example shown in Figs. 11(a) and 11(b) in terms of the arrangement of coils 53b and 61b. The following mainly describes the differences from the modified example described above. Fig. 12(a) is an end view of the stator and element unit of a modified example of this embodiment, and Fig. 12(b) is an end view of the rotor and element unit of a modified example of this embodiment.

[0080] 12(b), coil 53a is arranged to overlap with circumference C2, and coil 53b is arranged to overlap with circumference C4, which is different from circumference C2. For example, when viewed from the direction of the rotation axis D, the center of coil 53a is arranged to overlap with circumference C2 but not with circumference C4. When viewed from the direction of the rotation axis D, the center of coil 53b is arranged to overlap with circumference C4 but not with circumference C2.

[0081] 12(a), coil 61a is arranged to overlap with circumference C1, and coil 61b is arranged to overlap with circumference C3, which is different from circumference C1. For example, when viewed from the rotation axis direction D, the center of coil 61a is arranged to overlap with circumference C1 but not with circumference C3. When viewed from the rotation axis direction D, the center of coil 61b is arranged to overlap with circumference C3 but not with circumference C1. When viewed from the rotation axis direction D, circumferences C1 and C2 overlap with each other. When viewed from the rotation axis direction D, circumferences C3 and C4 overlap with each other.

[0082] Next, an example of an electrical signal detected by the output unit 80 in a modified example of this embodiment will be described using FIGS. 13(a), 13(b), 14(a), and 14(b). In this modified example, as in the modified examples shown in FIGS. 10, 11(a), and 11(b), multiple coils 53 and multiple coils 61 form multiple pairs that are magnetically coupled to each other. Specifically, four coils 53 and four coils 61 form four pairs that are magnetically coupled to each other. FIGS. 13(a), 13(b), 14(a), and 14(b) are graphs showing the frequency dependence of voltage at each temperature. The vertical axis represents the voltage detected by the output unit 80, and the horizontal axis represents the frequency of the voltage applied by the AC power supply PS.

[0083] The data D41 to D44 each represent data relating to a different pair of the plurality of pairs of the element unit 50 and the element unit 60. In other words, the data D41 to D44 each correspond to the coil 53 of the different element units 50, and represent a change in the temperature sensing element 51 of each element unit 50 in response to a change in the temperature inside the rotating electric machine MT.

[0084] In each of the data D41 to D44, the resonance frequencies of the element units 50 and 60 are the same. The resonance frequencies of the plurality of pairs of the element units 50 and 60 in the data D41 to D44 are different from one another.

[0085] The capacitance of the capacitor 55 is the same for all of the data D41 to D44. The capacitance of the capacitor 63 is the same for all of the data D41 to D44.

[0086] In data D41, the inductor values ​​of coils 53 and 61 are 50 μH. In data D42, the inductor values ​​of coils 53 and 61 are 40 μH. In data D43, the inductor values ​​of coils 53 and 61 are 30 μH. In data D44, the inductor values ​​of coils 53 and 61 are 20 μH. In this case, it was confirmed that the changes in the electrical resistance of the temperature sensing elements 51 in the multiple element units 50 can be output as temperature information from the output section 80 via different element units 60.

[0087] As described above, the temperature information output device 1 shown in FIG. 3 includes a plurality of element units 50 provided on the rotor 20 and an element unit 60 provided on the stator 10. The element unit 60 has a coil 61 that is magnetically coupled to each of the coils 53 of the plurality of element units 50. In this case, the resonant frequencies of the plurality of element units 50 are different from each other when the coils 53 and 61 are magnetically coupled. Therefore, an electrical signal corresponding to each of the plurality of element units 50 is output from the element unit 60. As a result, temperature information at a plurality of locations where the temperature sensing elements 51 of the plurality of element units 50 are respectively disposed can be output. Therefore, for example, the accuracy of temperature information at a plurality of locations inside the rotating electric machine T can be easily ensured.

[0088] The temperature information output device 1 shown in FIG. 10 includes a plurality of element units 50 provided on the rotor 20 and a plurality of element units 50 provided on the stator. Each of the plurality of element units 50 has a coil 61 magnetically coupled to a respective coil 53 of the plurality of element units 50. In this case, the resonant frequencies of the plurality of element units 50 differ from one another when the coils 53 and 61 forming corresponding pairs among the plurality of pairs of coils 53 and 61 are magnetically coupled. Therefore, an electrical signal corresponding to each of the plurality of element units 50 is output from the corresponding element unit 60 among the plurality of element units 60. As a result, temperature information at multiple locations where the temperature sensing elements 51 of the plurality of element units 50 are respectively disposed can be output. This can improve the accuracy of the temperature inside the rotating electric machine MT.

[0089] The rotating electric machine MT may include the above-mentioned temperature information output device 1, a stator 10, and a rotor 20. The rotor 20 may include a magnet 25, a plurality of steel plates M1 stacked in the rotational axis direction D of the rotor 20, and a shaft 21 extending in the rotational axis direction D. The plurality of temperature sensors 51 included in the plurality of element units 50 may include a mutually different temperature sensor 51a and a temperature sensor 51b. The temperature sensor 51a may be provided on the magnet 25. The temperature sensor 51b may be provided on the steel plate M1. In this case, since the temperature sensor 51a is provided on the magnet 25 and the temperature sensor 51b is provided on the steel plate M1, the rotating electric machine MT can easily output temperature information of the magnet 25 and the steel plate M1.

[0090] The plurality of temperature sensors 51 may further include a temperature sensor 51c different from the temperature sensors 51a and 51b. The temperature sensor 51c may be provided on the shaft. In this case, since the temperature sensor 51c is provided on the shaft 21, the rotating electric machine MT can easily output temperature information of the magnet 25, the steel plate M1, and the shaft 21.

[0091] While the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. In the rotating electric machine MT, the coils 53 and 61 do not have to be arranged so as to face each other in the direction of the rotation axis D when the rotor 20 is at a predetermined rotation angle position.

[0092] In a rotating electric machine MT in which coils 53 and 61 are arranged so as to face each other in the direction of the rotation axis D when the rotor 20 is at a predetermined rotation angle position, as described above, the magnetic flux generated in the stator coil 11 is unlikely to affect coils 53 and 61.

[0093] In the rotating electric machine MT, the temperature sensing element 51 does not have to be arranged so as to be in contact with the surface 25a of the magnet 25. The entire magnet 25 and part of the coil 53 do not have to be arranged inside the rotor core 23.

[0094] The control circuit 41 does not have to function as a temperature acquisition device. The control circuit 41 may control the drive state of the rotating electric machine MT based on the electrical signal input from the output unit 80. In this case, the control circuit 41 may control the drive state of the rotating electric machine MT as follows. When the electrical signal input from the output unit 80 determines that the temperature of the magnet 25 has risen to a predetermined first threshold, the control circuit 41 controls the drive frequency to decrease so as to limit the rotation speed of the rotating electric machine MT. When the electrical signal input from the output unit 80 determines that the temperature of the magnet 25 has fallen to a predetermined second threshold that is lower than the first threshold, the control circuit 41 controls the drive frequency to increase so as to remove the limit on the rotation speed of the rotating electric machine MT.

[0095] In the above-described embodiment and modified examples, the magnet 25 is a permanent magnet, but the magnet 25 may also be an electromagnet. For example, instead of a motor using a permanent magnet, a wound-field motor can be adopted. A wound-field motor has windings that generate a magnetic field when a current is passed through them instead of permanent magnets. The windings are field coils. A wound-field motor includes, for example, multiple field coils provided in a stator.

[0096] As can be understood from the above description of the embodiments and modifications, this specification includes disclosure of the following aspects. (Appendix 1) 1. A temperature information output device provided in a rotating electric machine having a stator and a rotor, the temperature information output device outputting temperature information relating to temperatures of portions of the rotor, a plurality of first element units provided on the rotor, each of which has a temperature sensing element whose electrical resistance changes depending on the temperature of the portion and a first coil electrically connected to the temperature sensing element; a second element unit provided on the stator, the second element unit having a second coil magnetically coupled to the first coil of each of the plurality of first element units; an output unit electrically connected to the second element unit, the resonance frequencies of the plurality of first element units in a state in which the first coil and the second coil are magnetically coupled to each other are different from each other, The output unit outputs the electrical signal output from the second element unit as the temperature information. (Appendix 2) 1. A temperature information output device provided in a rotating electric machine having a stator and a rotor, the temperature information output device outputting temperature information relating to temperatures of portions of the rotor, a plurality of first element units provided on the rotor, each of which has a temperature sensing element whose electrical resistance changes depending on the temperature of the portion and a first coil electrically connected to the temperature sensing element; a plurality of second element units provided on the stator, each of which has a second coil magnetically coupled to the first coil; an output unit electrically connected to the second element unit, the first coils of the first element units and the second coils of the second element units form a plurality of pairs that are magnetically coupled to each other, the resonant frequencies of the plurality of first element units in a state in which the first coil and the second coil forming a corresponding pair among the plurality of pairs are magnetically coupled to each other are different from each other, The output unit outputs the electrical signal output from the second element unit as the temperature information. (Appendix 3) a temperature information output device according to claim 1 or 2, the stator, and the rotor; the rotor includes a magnet, a plurality of steel plates stacked in a rotation axis direction of the rotor, and a shaft extending in the rotation axis direction, the plurality of temperature sensitive elements included in the plurality of first element units include a first temperature sensitive element and a second temperature sensitive element that are different from each other; The first temperature sensitive element is provided on the magnet, The rotating electric machine, wherein the second temperature-sensitive element is provided on the steel plate. (Appendix 4) the plurality of temperature sensitive elements further include a third temperature sensitive element different from the first temperature sensitive element and the second temperature sensitive element, 4. The rotating electric machine according to claim 3, wherein the third temperature sensitive element is provided on the shaft. [Explanation of symbols]

[0097] 1...temperature information output device, 51, 51a, 51b, 51c...temperature-sensing element, 10...stator, 20...rotor, 21...shaft, 25...magnet, 80...output section, D...rotation axis direction, M1...steel plate, MT...rotating electric motor.

Claims

1. 1. A temperature information output device provided in a rotating electric machine having a stator and a rotor, the temperature information output device outputting temperature information relating to temperatures of portions of the rotor, a plurality of first element units provided on the rotor, each of which has a temperature sensing element whose electrical resistance changes depending on the temperature of the portion and a first coil electrically connected to the temperature sensing element; a second element unit provided on the stator, the second element unit having a second coil magnetically coupled to the first coil of each of the plurality of first element units; an output unit electrically connected to the second element unit, the resonance frequencies of the plurality of first element units in a state in which the first coil and the second coil are magnetically coupled to each other are different from each other, The output unit outputs the electrical signal output from the second element unit as the temperature information.

2. 1. A temperature information output device provided in a rotating electric machine having a stator and a rotor, the temperature information output device outputting temperature information relating to temperatures of portions of the rotor, a plurality of first element units provided on the rotor, each of which has a temperature sensing element whose electrical resistance changes depending on the temperature of the portion and a first coil electrically connected to the temperature sensing element; a plurality of second element units provided on the stator, each of which has a second coil magnetically coupled to the first coil; an output unit electrically connected to the second element unit, the first coils of the first element units and the second coils of the second element units form a plurality of pairs that are magnetically coupled to each other, the resonant frequencies of the plurality of first element units in a state in which the first coil and the second coil forming a corresponding pair among the plurality of pairs are magnetically coupled to each other are different from each other, The output unit outputs the electrical signal output from the second element unit as the temperature information.

3. A temperature information output device comprising: the temperature information output device according to claim 1 or 2; the stator; and the rotor; the rotor includes a magnet, a plurality of steel plates stacked in a rotation axis direction of the rotor, and a shaft extending in the rotation axis direction, the plurality of temperature sensitive elements included in the plurality of first element units include a first temperature sensitive element and a second temperature sensitive element that are different from each other; The first temperature sensitive element is provided on the magnet, The rotating electric machine, wherein the second temperature-sensitive element is provided on the steel plate.

4. the plurality of temperature sensitive elements further include a third temperature sensitive element different from the first temperature sensitive element and the second temperature sensitive element, The rotating electric machine according to claim 3 , wherein the third temperature sensitive element is provided on the shaft.

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