Temperature characteristic data determination method

Abstract

To provide a temperature characteristic data determination method for determining appropriate temperature characteristic data.SOLUTION: A temperature characteristic data determination method is applied to a temperature information output device that is provided for a rotary electric machine including a stator and a rotor and outputs temperature information regarding the temperature of a portion in the rotor. The temperature characteristic data determination method includes determining an application frequency indicating a frequency of an AC voltage applied to the second coil so as to correspond to a facing distance between the first coil and the second coil, and determining, for each of a plurality of frequencies, temperature characteristic data corresponding to the applied frequency as target temperature characteristic data to be used when obtaining the temperature of the site using temperature information, with reference to a database that stores, in association with each other, temperature characteristic data indicating a relationship between the temperature and a value based on an electrical signal corresponding to the frequency and a magnitude of a voltage drop.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a temperature characteristic data determination method. [Background technology]

[0002] A magnet temperature information output device is known that is provided in a rotating electric machine having a stator and a rotor in which a permanent magnet is arranged, and outputs temperature information related to the temperature of the permanent magnet (see, for example, Patent Document 1). This magnet temperature information output device includes a temperature sensor, a first coil, a second coil, and an output unit. The temperature sensor is provided in the rotor, and its electrical resistance changes depending on the temperature of the permanent magnet. The first coil is electrically connected to the temperature sensor. The second coil is provided in the stator and magnetically coupled to the first coil. The output unit outputs an electrical signal corresponding to the magnitude of the current flowing through the second coil. [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] An object of an aspect of the present invention is to provide a temperature characteristic data determination method for determining appropriate temperature characteristic data. [Means for solving the problem]

[0005] A temperature characteristic data determination method according to one aspect of the present invention is a temperature characteristic data determination method for a temperature information output device provided in a rotating electric machine having a stator and a rotor, which outputs temperature information related to the temperature of a portion of the rotor. The temperature information output device includes a first element unit provided in the rotor, a second element unit provided in the stator, an electrical resistance element, and an output unit. The first element unit has a temperature sensing element whose electrical resistance changes depending on the temperature of the portion of the rotor, and a first coil electrically connected to the temperature sensing element. The second element unit has a second coil magnetically coupled to the first coil. The electrical resistance element is electrically connected to the second element unit. The output unit is electrically connected to the second element unit and the electrical resistance element, and outputs an electrical signal corresponding to the magnitude of a voltage drop occurring in the electrical resistance element as temperature information. The temperature characteristic data determination method includes determining an applied frequency indicating the frequency of the AC voltage to be applied to the second coil so as to correspond to the opposing distance between the first coil and the second coil, and referring to a database that stores, for each of a plurality of frequencies, temperature characteristic data indicating the relationship between the frequency and a value based on an electrical signal corresponding to the magnitude of voltage drop and temperature, in association with each other, to determine the temperature characteristic data corresponding to the applied frequency as target temperature characteristic data to be used when obtaining the temperature of the above-mentioned portion of the rotor using a temperature information output device.

[0006] For example, the electrical signal output as temperature information is used to obtain the temperature of a portion of the rotor. To obtain the temperature of the portion, for example, an electrical signal is output by applying an AC voltage of a predetermined frequency corresponding to the distance between the first coil and the second coil to the second coil. Temperature characteristic data indicating the relationship between the temperature and a value based on the electrical signal corresponding to the magnitude of the voltage drop is then referenced, and the temperature corresponding to the value based on the output electrical signal is obtained as the temperature of the portion. For example, the temperature characteristic data is used under a condition in which an AC voltage of a frequency corresponding to the distance between the first coil and the second coil is applied to the second coil. However, the distance between the first coil and the second coil may deviate from the distance corresponding to the frequency of the AC voltage applied to the second coil due to, for example, installation error. If the temperature of the portion is obtained using temperature characteristic data under a condition in which an AC voltage of a frequency corresponding to the distance is applied to the second coil, even though the distance between the first coil and the second coil deviates from the distance corresponding to the frequency of the AC voltage applied to the second coil, a discrepancy may occur between the obtained temperature and the actual temperature. In other words, when obtaining the temperature of the above-mentioned portion, if the combination of the facing distance and the frequency does not correspond to the temperature characteristic data used, there is a risk of a discrepancy between the obtained temperature and the actual temperature. Therefore, a method for determining appropriate temperature characteristic data is desired.

[0007] In the above aspect, the applied frequency is determined so as to correspond to the distance between the first coil and the second coil, and the temperature characteristic data corresponding to the applied frequency is determined as the target temperature characteristic data. Therefore, in the above aspect, the temperature characteristic data under the condition that an AC voltage having a frequency corresponding to the distance between the first coil and the second coil is applied to the second coil is determined as the target temperature characteristic data. That is, in the above aspect, the temperature characteristic data corresponding to the combination of the distance between the first coil and the second coil and the frequency of the AC voltage applied to the second coil is determined as the target temperature characteristic data. Therefore, in the above aspect, appropriate temperature characteristic data is determined.

[0008] In one of the above aspects, determining the applied frequency may include determining, as the applied frequency, the frequency of the AC voltage whose phase difference with the electrical signal output from the output section is within a predetermined range when the temperature of the temperature-sensing element is at room temperature. When the frequency of the AC voltage that brings the phase difference into a predetermined range is determined as the applied frequency, the frequency that corresponds to the opposing distance between the first coil and the second coil is reliably determined as the applied frequency.

[0009] In one of the above aspects, determining the applied frequency may include determining as the applied frequency the frequency at which the value based on the electrical signal output from the output section becomes an extreme value when the temperature of the temperature-sensitive element is at room temperature. When the frequency at which the value based on the electrical signal becomes an extreme value is determined as the applied frequency, the frequency corresponding to the opposing distance between the first coil and the second coil is reliably determined as the applied frequency.

[0010] Another aspect of the present invention provides a temperature characteristic data determination method applicable to 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 the temperature of a portion of the rotor. The temperature information output device includes a first element unit provided in the rotor, a second element unit provided in the stator, an electrical resistance element, and an output unit. The first element unit includes a temperature sensing element whose electrical resistance changes in response to the temperature of the portion of the rotor, and a first coil electrically connected to the temperature sensing element. The second element unit includes a second coil magnetically coupled to the first coil. The electrical resistance element is electrically connected to the second element unit. The output unit is electrically connected to the second element unit and the electrical resistance element, and outputs an electrical signal corresponding to the magnitude of a voltage drop occurring in the electrical resistance element as temperature information. The temperature characteristic data determination method includes applying an AC voltage to the second coil when the thermosensitive element is at a predetermined temperature, the AC voltage having a frequency lower than a predetermined resonant frequency that excites the first coil; acquiring an electrical signal output from the output unit by the application; and referring to a database that stores a plurality of temperature characteristic data that indicate the relationship between a value based on the electrical signal corresponding to the magnitude of the voltage drop and the temperature, determining, as target temperature characteristic data to be used when obtaining the temperature of a part using temperature information, the temperature characteristic data that corresponds to the value based on the acquired electrical signal, with the value based on the electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature.

[0011] Even if the facing distance between the first coil and the second coil and the frequency of the AC voltage applied to the second coil do not correspond to each other, there is one temperature characteristic data corresponding to the combination of the facing distance and the frequency. When the frequency of the AC voltage applied to the second coil is lower than the predetermined resonant frequency, the difference between the values ​​based on the electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature in each temperature characteristic data is likely to increase. Therefore, when the frequency of the AC voltage applied to the second coil is lower than the predetermined resonant frequency, the temperature characteristic data corresponding to the combination of the facing distance and the frequency is likely to be identified by the value based on the electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature. When the temperature characteristic data for the combination of the facing distance and the frequency is used to obtain the temperature of a portion of the rotor, there is little discrepancy between the obtained temperature and the actual temperature.

[0012] In another aspect of the invention, when the temperature-sensing element is at a predetermined temperature, an AC voltage having a frequency lower than a predetermined resonant frequency for exciting the first coil is applied to the second coil, thereby acquiring an electrical signal output from the output unit. A database is referenced, and a value based on the electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature, that is, temperature characteristic data corresponding to the value based on the acquired electrical signal, is determined as the target temperature characteristic data. That is, in the another aspect of the invention, temperature characteristic data corresponding to the combination of the opposing distance between the first coil and the second coil and the frequency of the AC voltage applied to the second coil is determined as the target temperature characteristic data. Therefore, in the another aspect of the invention, appropriate temperature characteristic data is determined.

[0013] According to yet another aspect of the present invention, a temperature characteristic data determination device is provided for a rotating electric machine having a stator and a rotor, and is applicable to a temperature information output device that outputs temperature information related to the temperature of a portion of the rotor. The temperature information output device includes a first element unit provided on the rotor, a second element unit provided on the stator, an electrical resistance element, and an output unit. The first element unit has a temperature sensing element whose electrical resistance changes depending on the temperature of the portion of the rotor, and a first coil electrically connected to the temperature sensing element. The second element unit has a second coil magnetically coupled to the first coil. The electrical resistance element is electrically connected to the second element unit. The output unit is electrically connected to the second element unit and the electrical resistance element, and outputs an electrical signal corresponding to the magnitude of a voltage drop occurring in the electrical resistance element as temperature information. The temperature characteristic data determination device determines an application frequency indicating the frequency of an AC voltage to be applied to the second coil so as to correspond to the opposing distance between the first coil and the second coil. The temperature characteristic data determination device refers to a database that stores, for each of a plurality of frequencies, temperature characteristic data that indicates the relationship between the frequency and a value based on an electrical signal corresponding to the magnitude of voltage drop and temperature, in association with each other, and determines the temperature characteristic data that corresponds to the applied frequency as the target temperature characteristic data to be used when obtaining the temperature of the above-mentioned part using the temperature information.

[0014] According to yet another aspect of the present invention, a temperature characteristic data determination device is provided for a rotating electric machine having a stator and a rotor, and is applicable to a temperature information output device that outputs temperature information related to the temperature of a portion of the rotor. The temperature information output device includes a first element unit provided on the rotor, a second element unit provided on the stator, an electrical resistance element, and an output unit. The first element unit has a temperature sensing element whose electrical resistance changes depending on the temperature of the portion of the rotor, and a first coil electrically connected to the temperature sensing element. The second element unit has a second coil magnetically coupled to the first coil. The electrical resistance element is electrically connected to the second element unit. The output unit is electrically connected to the second element unit and the electrical resistance element, and outputs an electrical signal corresponding to the magnitude of a voltage drop occurring in the electrical resistance element as temperature information. The temperature characteristic data determination device obtains the electrical signal output from the output unit by applying an AC voltage having a frequency lower than a predetermined resonant frequency that excites the first coil to the second coil when the temperature sensing element is at a predetermined temperature. The temperature characteristic data determination device refers to a database that stores multiple temperature characteristic data, each indicating the relationship between a value based on an electrical signal corresponding to the magnitude of a voltage drop and temperature, and determines the temperature characteristic data corresponding to the value based on the acquired electrical signal, which value is based on the electrical signal corresponding to the magnitude of the voltage drop at a predetermined temperature, as target temperature characteristic data to be used when obtaining the temperature of the above-mentioned part using temperature information.

[0015] According to yet another aspect of the present invention, there is provided a temperature characteristic data determination method applicable to a temperature information output device for outputting temperature information relating to the temperature of a portion of a rotor of a rotating electric machine having a stator and a rotor. The temperature information output device includes a first element unit, a second element unit, an electrical resistance element, and an output unit. The first element unit includes a temperature sensing element whose electrical resistance changes in response to the temperature of the portion, and a first coil electrically connected to the temperature sensing element. The second element unit includes a second coil magnetically coupled to the first coil. The electrical resistance element is electrically connected to the second element unit. The output unit is electrically connected to the second element unit and the electrical resistance element, and outputs an electrical signal corresponding to the magnitude of a voltage drop occurring in the electrical resistance element as temperature information. The temperature characteristic data determination method includes acquiring a first composite impedance and adjusting the second composite impedance to a value corresponding to the first composite impedance. In the acquiring step, the first composite impedance is the composite impedance of the first coil and the second coil when, in a first state in which the first element unit is attached to the rotor and the second element unit is attached to the stator, an AC voltage is applied to the second coil, the first coil and the second coil are magnetically coupled, and the temperature-sensitive element is at a predetermined temperature. In the adjusting step, the second composite impedance is the composite impedance of the first coil and the second coil when, in a second state in which the first element unit and the second element unit are attached to a temperature characteristic data acquisition device, an AC voltage is applied to the second coil, the first coil and the second coil are magnetically coupled, and the temperature-sensitive element is at a predetermined temperature. The temperature characteristic data acquisition device is used to generate temperature characteristic data indicating the relationship between a value based on an electrical signal and temperature, and is a device separate from the rotating electric machine. The temperature characteristic data determination method includes, after the adjusting step, generating temperature characteristic data and storing the temperature characteristic data in a database. In the generating step, the temperature characteristic data is generated by applying an AC voltage to the second coil in the second state and outputting an electrical signal while changing the temperature of the temperature-sensitive element.The storing step includes storing the frequency of the AC voltage applied to the second coil in the generating step and the generated temperature characteristic data in a database in association with each other.

[0016] For example, when obtaining the temperature of the part based on the electrical signal output as temperature information, temperature characteristic data stored in a database is referenced, and the temperature corresponding to the output electrical signal is obtained as the temperature of the part. That is, the temperature characteristic data used to obtain the temperature of the part is determined from the temperature characteristic data stored in the database. Here, the temperature characteristic data may be generated using a device other than the rotating electric machine. As a result, the relationship between the value based on the electrical signal corresponding to the magnitude of the voltage drop in the rotating electric machine and the temperature based on the electrical signal in the other device may not correspond to each other. If the relationship in the rotating electric machine does not correspond to the relationship in the other device, the relationship indicated by the generated temperature characteristic data is unlikely to correspond to the relationship in the rotating electric machine. For example, if temperature characteristic data that does not correspond to the relationship in the rotating electric machine is stored in the database, appropriate temperature characteristic data may not be determined when obtaining the temperature of the part by referring to the database.

[0017] In yet another aspect of the invention, the temperature characteristic data is generated after the second synthetic impedance is adjusted to a value corresponding to the first synthetic impedance. Here, the correspondence between the relationship in the rotating electric machine and the relationship between the temperature and a value based on an electrical signal corresponding to the magnitude of the voltage drop in the temperature characteristic data acquisition device can be reflected in the correspondence between the first synthetic impedance and the second synthetic impedance. That is, by adjusting the second synthetic impedance to a value corresponding to the first synthetic impedance, the relationship in the temperature characteristic data acquisition device corresponds to the relationship in the rotating electric machine. Therefore, in yet another aspect of the invention, the temperature characteristic data is generated in a state in which the relationship in the temperature characteristic data acquisition device corresponds to the relationship in the rotating electric machine. As a result, temperature characteristic data that does not correspond to the relationship in the rotating electric machine is prevented from being stored in the database, and the temperature characteristic data used to obtain the temperature of the portion is selected from the temperature characteristic data that corresponds to the relationship in the rotating electric machine. Based on the above, the yet another aspect of the invention determines appropriate temperature characteristic data.

[0018] In the above still another aspect, the adjusting may include adjusting the second composite impedance to a value within a range of 95% to 105% of the first composite impedance. When the second synthetic impedance is adjusted to a value within a range of 95% to 105% of the first synthetic impedance, the temperature characteristic data is generated in a state in which the relationship in the temperature characteristic data acquisition device more closely corresponds to the relationship in the rotating electric machine. Therefore, when the second synthetic impedance is adjusted to the above value, more appropriate temperature characteristic data is determined.

[0019] Yet another aspect of the above may include determining an applied frequency indicating the frequency of the AC voltage to be applied to the second coil so as to correspond to the opposing distance between the first coil and the second coil in the first state, and referring to a database, determining temperature characteristic data corresponding to the applied frequency as target temperature characteristic data to be used when obtaining the temperature of the part using the temperature information. As described above, the database stores temperature characteristic data generated in a state where the relationship in the temperature characteristic data acquisition device corresponds to the relationship in the rotating electrical machine, thereby preventing temperature characteristic data that does not correspond to the relationship in the rotating electrical machine from being determined as the target temperature characteristic data, and ensuring that appropriate temperature characteristic data is determined. [Effects of the Invention]

[0020] An aspect of the present invention provides a temperature characteristic data determination method for determining appropriate temperature characteristic data. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a magnet temperature information output device and a rotating electric machine. [Figure 2] FIG. 2 is a circuit diagram showing an example of a magnet temperature information output device. [Figure 3] FIG. 3 is a block diagram illustrating functional elements of a temperature characteristic data determination device according to an embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the database. [Figure 5] FIG. 5 is a flowchart showing an example of processing in the temperature characteristic data determination device according to this embodiment. [Figure 6] FIG. 6 is a diagram showing the relationship between the temperature and an electrical signal corresponding to a voltage drop occurring in an electrical resistance element. [Figure 7] FIG. 7 is a diagram showing the relationship between the temperature and an electrical signal corresponding to a voltage drop occurring in an electrical resistance element. [Figure 8] FIG. 8 is a diagram illustrating another example of the database. [Figure 9] FIG. 9 is a flowchart showing another example of the process in the temperature characteristic data determination device according to this embodiment. [Figure 10] FIG. 10 is a diagram showing the relationship between the temperature and an electrical signal corresponding to a voltage drop occurring in an electrical resistance element. [Figure 11]FIG. 11 is a schematic diagram showing the configuration of a temperature characteristic data acquisition device. [Figure 12] FIG. 12 is a flowchart showing a temperature characteristic data determination method according to another embodiment. [Figure 13] FIG. 13 is a diagram showing the relationship between the frequency of the AC voltage and the first synthetic impedance. [Figure 14] FIG. 14 is a flowchart showing the procedure for adjusting the second synthetic impedance. [Figure 15] FIG. 15 is a flowchart showing a temperature characteristic data determination method according to another embodiment. [Figure 16] FIG. 16 is a diagram showing the relationship between the temperature and an electrical signal corresponding to a voltage drop occurring in an electrical resistance element. DETAILED DESCRIPTION OF THE INVENTION

[0022] 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.

[0023] (First embodiment) Prior to describing the temperature characteristic data determination method and the temperature characteristic data determination device 1 according to this embodiment, the configuration of a magnet temperature information output device OD to which this determination method and temperature characteristic data determination device 1 are applied and a rotating electric machine MT provided with the magnet temperature information output device OD will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the configuration of the magnet temperature information output device and the rotating electric machine.

[0024] As shown in FIG. 1, the magnet temperature information output device OD 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. 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.

[0025] The rotor 20 includes a shaft 21, a rotor core 23, and a plurality of permanent 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. Each permanent 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 phrase "the extension direction of the permanent magnet 25 is parallel to the central axis of the shaft 21" does not necessarily mean that the extension direction of the permanent magnet 25 is parallel to the central axis of the shaft 21. The extension direction of the permanent magnet 25 may be considered to be parallel to the central axis of the shaft 21 even if there is a slight difference, manufacturing error, or measurement error within a predetermined range. When slight differences within a predetermined range are included, for example, when the angle between the extension direction of the permanent magnet 25 and the central axis of the shaft 21 is within a range of ±2 degrees, the extension direction of the permanent magnet 25 and the central axis of the shaft 21 may be considered parallel. 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 permanent 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. Even when slight differences, manufacturing errors, or measurement errors within a predetermined range are included, the angular intervals may be considered equal. If there is a slight difference within a preset range, for example, if each angular interval of the permanent magnet 25 relative to the axis of rotation of the rotor 20 is within a range of ±10% of the average angular interval of all angular intervals, then each angular interval of the permanent magnet 25 relative to the axis of rotation of the rotor 20 may be considered to be uniform.

[0026] When the rotating electric machine MT is an IPM motor, the multiple permanent magnets 25 are arranged inside the rotor core 23. When the rotating electric machine MT is an SPM motor, the multiple permanent magnets 25 are arranged on the surface of the rotor core 23. Each permanent magnet 25 includes a rare earth permanent magnet. Each permanent magnet 25 includes, for example, a neodymium sintered magnet. Each permanent magnet 25 may include a sintered magnet other than a rare earth permanent 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-deformed magnet.

[0027] 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.

[0028] 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.

[0029] Next, the configuration of the magnet temperature information output device OD will be described in more detail with reference to Fig. 2. Fig. 2 is a circuit diagram showing an example of a magnet temperature information output device. The magnet temperature information output device OD outputs temperature information related to the temperature of the permanent magnet 25. To achieve this function, the magnet temperature information output device OD includes an element unit 50, an element unit 60, an electrical resistance element 70, and an output unit 80. In this embodiment, there is one element unit 50 and one element unit 60. The element unit 50 is provided on the rotor 20. The element unit 60 is provided on the stator 10. The element unit 60 is provided, for example, on the stator core. The element unit 50 and the element unit 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 term "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 a slight difference, manufacturing error, or measurement error within a predetermined range is included, the direction may be considered to be parallel to the rotation axis of the rotor 20. If there is a slight difference within a preset range, for example, if the direction forms an angle with the rotation axis of rotor 20 within a range of ±2 degrees, it may be considered to be a direction parallel to the rotation axis of rotor 20.

[0030] As shown in FIG. 2 , the element unit 50 includes a temperature sensor 51 and a coil 53. The temperature sensor 51 and the coil 53 are provided on the rotor 20. The temperature sensor 51 is provided on at least one of the multiple permanent magnets 25. In this embodiment, the temperature sensor 51 is provided on only one permanent magnet 25. The temperature sensor 51 is arranged so as to be in contact with the permanent magnet 25. The temperature sensor 51 may be arranged near the permanent magnet 25. The electrical resistance of the temperature sensor 51 changes depending on the temperature of the permanent magnet 25. The electrical resistance of the temperature sensor 51 decreases as the temperature of the permanent magnet 25 increases. The temperature sensor 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 sensor 51. In this embodiment, both ends of the coil 53 are electrically connected to both ends of the temperature sensor 51.

[0031] The element unit 50 may further include a capacitor in addition to the temperature sensing element 51 and the coil 53. The capacitor may, for example, form an LC resonant circuit together with the coil 53. The capacitor may, for example, form an LC resonant circuit together with the coil 53 and the coil 61. The capacitor may, for example, be inserted so as to be connected in parallel with the coil 53.

[0032] The element unit 60 includes a coil 61 and a capacitor 63. The coil 61 is disposed 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 53 and 61 are disposed 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 61 is magnetically coupled to the coil 53. 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. The capacitor 63 and the coil 61 form an LC resonant circuit. The capacitor 63 may form an LC resonant circuit together with the coil 53 and the coil 61. The capacitor 63 is inserted so as to be connected in parallel to the coil 61, for example. For example, when the coil 53 forms a first coil, the coil 61 forms a second coil. For example, when the element unit 50 forms a first element unit, the element unit 60 forms a second element unit.

[0033] For example, the predetermined frequency may be equal to or lower than a predetermined resonant frequency that excites coil 53. That is, the frequency of the AC voltage applied to coil 61 may be equal to or lower than the predetermined resonant frequency that excites coil 53. The predetermined resonant frequency is, for example, the resonant frequency of a circuit equivalent to the circuit in magnet temperature information output device OD when coils 53 and 61 are magnetically coupled and the temperature of temperature sensor 51 is at a predetermined temperature. In this embodiment, the circuit is a circuit including temperature sensor 51, coil 53, coil 61, and capacitor 63. The predetermined temperature is, for example, room temperature. Room temperature is, for example, 15°C or higher and 30°C or lower. In this embodiment, the predetermined temperature is 25°C. The difference between the frequency of the AC voltage applied to coil 61 and the predetermined resonant frequency may be 5 kHz or higher and 30 kHz or lower.

[0034] The predetermined resonant frequency varies depending on, for example, the distance between the coil 53 and the coil 61. That is, in the magnet temperature information output device OD, there is a predetermined resonant frequency corresponding to the distance between the coil 53 and the coil 61. The predetermined resonant frequency corresponding to the distance between the coil 53 and the coil 61 is the resonant frequency of a circuit in the magnet temperature information output device OD, in which the coupling constant between the coil 53 and the coil 61 is a value corresponding to the distance. The distance between the coil 53 and the coil 61 is determined, for example, by the distance between the coil 53 and the coil 61 in the rotation axis direction D when the rotor 20 is at the above-mentioned predetermined rotation angle. In this embodiment, the predetermined frequency may be equal to or less than the predetermined resonant frequency corresponding to the distance between the coil 53 and the coil 61. In this embodiment, the frequency of the AC voltage applied to the coil 61 is determined by the temperature characteristic data determination device 1.

[0035] 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.

[0036] The output unit 80 is electrically connected to the element unit 60 and the electrical resistance element 70. The output unit 80 may be electrically connected to the coil 61. That is, the coil 61 may be electrically connected to the electrical resistance element 70 and the output unit 80. In this embodiment, the output unit 80 is provided on the stator 10. The output unit 80 outputs an electrical signal corresponding to the magnitude of a voltage drop occurring in the electrical resistance element 70. The output unit 80 may output an electrical signal indicating the magnitude of the voltage drop occurring 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 above-mentioned electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. The output unit 80 may include the electrical resistance element 70. When the output section 80 includes the electrical resistance element 70 , the electrical resistance element 70 may be an internal resistance of the output section 80 .

[0037] A magnetic flux corresponding to the applied AC voltage is generated in the coil 61. In this embodiment, 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.

[0038] Since the electrical resistance of the temperature sensitive element 51 changes in accordance with the temperature of the permanent magnet 25, the magnetic flux generated in the coil 61 changes in accordance with the change in the electrical resistance of the temperature sensitive element 51. This causes a change in the current flowing through the coil 61. The change in the current flowing through the coil 61 causes a change in the magnitude of the voltage drop occurring in the electrical resistance element 70.

[0039] As the temperature of the permanent magnet 25 rises and the electrical resistance of the temperature-sensitive element 51 decreases, the magnetic flux generated in the coil 61 increases. As a result, the current flowing through the coil 61 increases, and the magnitude of the voltage drop generated in the electrical resistance element 70 also increases. As the temperature of the permanent magnet 25 falls and the electrical resistance of the temperature-sensitive element 51 increases, the magnetic flux generated in the coil 61 decreases. As a result, the current flowing through the coil 61 decreases, and the magnitude of the voltage drop generated in the electrical resistance element 70 also decreases. In other words, as the temperature of the permanent magnet 25 rises, the magnitude of the voltage drop generated in the electrical resistance element 70 increases. Similarly, as the temperature of the permanent magnet 25 falls, the magnitude of the voltage drop generated in the electrical resistance element 70 decreases.

[0040] 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 of the permanent magnet 25. Therefore, the electrical signal output from the output unit 80 includes temperature information related to the temperature of the permanent magnet 25. 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 of the permanent magnet 25 is transmitted wirelessly between the element unit 50 and the output unit 80 via the element unit 60.

[0041] 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 corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70 output from the magnet temperature information output device OD. The control circuit 41 acquires the temperature of the permanent magnet 25 based on the acquired electrical signal. That is, in this embodiment, the control circuit 41 functions as a magnet temperature acquisition device.

[0042] The control circuit 41 obtains the temperature of the permanent magnet 25, for example, as follows. First, the control circuit 41 refers to temperature characteristic data indicating the relationship between the temperature and a value based on an electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. The temperature characteristic data may be stored in the control circuit 41 or may be stored in an external server separate from the control circuit 41. Next, the control circuit 41 obtains, as the temperature of the permanent magnet 25, a temperature corresponding to a value based on the acquired electrical signal in the temperature characteristic data. For example, the control circuit 41 obtains, as the temperature of the permanent magnet 25, a temperature at which the value based on the acquired electrical signal is the same as the value in the temperature characteristic data. Alternatively, the control circuit 41 may obtain, as the temperature of the permanent magnet 25, a temperature at which the difference between the value based on the acquired electrical signal and the temperature characteristic data is smallest. In this embodiment, the temperature characteristic data used by the control circuit 41 to obtain the temperature of the permanent magnet 25 is determined by the temperature characteristic data determination device 1.

[0043] The control circuit 41 controls the driving state of the rotating electric machine MT based on the obtained temperature of the permanent magnet 25. 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 temperature of the permanent magnet 25 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 temperature of the permanent magnet 25 has fallen to a predetermined second threshold that is lower 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.

[0044] 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 temperature of the permanent magnet 25. When the control circuit 41 determines that the obtained temperature of the permanent 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 control circuit 41 determines that the obtained temperature of the permanent magnet 25 has fallen 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.

[0045] 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 of the permanent magnet 25 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.

[0046] Next, a temperature characteristic data determination device 1 that executes the temperature characteristic data determination method according to this embodiment will be described with reference to FIG. 3. FIG. 3 is a block diagram showing functional elements of the temperature characteristic data determination device according to this embodiment. The temperature characteristic data determination device 1 includes, for example, a central processing unit (CPU), a read-only memory (ROM), and a random access memory (RAM). The temperature characteristic data determination device 1 determines temperature characteristic data used by the control circuit 41 to obtain the temperature of the permanent magnet 25, for example, by loading a program stored in the ROM into the RAM and executing it on the CPU. For example, the temperature characteristic data determination device 1 determines the temperature characteristic data after the magnet temperature information output device OD is installed in the rotating electric machine MT and before the control circuit 41 obtains the temperature of the permanent magnet 25 for the first time. Hereinafter, the "temperature characteristic data used by the control circuit 41 to obtain the temperature of the permanent magnet 25" may be referred to as "target temperature characteristic data."

[0047] The temperature characteristic data determination device 1 is connected to the magnet temperature information output device OD and the control circuit 41. The temperature characteristic data determination device 1 determines the target temperature characteristic data by referring to the database DB. The temperature characteristic data determination device 1 accesses the database DB via a predetermined communication network. The predetermined communication network includes, for example, at least one of the Internet and an intranet. The predetermined communication network is configured using, for example, at least one of a wired network and a wireless network. In this embodiment, the database DB is included in a device different from the temperature characteristic data determination device 1. The database DB may be a part of the temperature characteristic data determination device 1. That is, the temperature characteristic data determination device 1 may include the database DB.

[0048] In this embodiment, the database DB stores information indicating the correspondence between frequency and temperature characteristic data. An example of the data configuration of the information stored in the database DB will be described below with reference to FIG. 4. FIG. 4 is a diagram showing an example of the database. In the example shown in FIG. 4, each data record of the information includes, as data items, a frequency, a temperature, and a voltage value. In the example shown in FIG. 4, frequencies are stored in the database DB in 5 kHz increments within a range of 320 kHz to 370 kHz. In this embodiment, a combination of a temperature and a voltage value in a data record group related to one frequency constitutes temperature characteristic data corresponding to that frequency. The database DB stores, for each of a plurality of frequencies, the frequency and temperature characteristic data in association with each other. That is, the database DB stores a plurality of temperature characteristic data.

[0049] The data record of the information indicating the correspondence between frequency and temperature characteristic data is generated using, for example, an equivalent circuit. For example, the equivalent circuit is a circuit that equivalently represents a circuit including the temperature sensor 51, coil 53, coil 61, capacitor 63, AC power supply PS, and electrical resistance element 70 in the magnet temperature information output device OD. In other words, the equivalent circuit includes elements corresponding to the temperature sensor 51, coil 53, coil 61, capacitor 63, AC power supply PS, and electrical resistance element 70.

[0050] When the above-described equivalent circuit is used, each data record group is generated, for example, as follows. First, the element corresponding to AC power supply PS is set as a power supply that applies an AC voltage to the element corresponding to coil 61. Then, while changing the temperature of the element corresponding to temperature sensing element 51, the voltage value across the element corresponding to capacitor 63 is acquired as a value corresponding to the voltage drop occurring in the element corresponding to electrical resistance element 70. Then, the frequency of the AC voltage applied to the element corresponding to coil 61 is associated with the temperature corresponding to temperature sensing element 51 and the acquired voltage value across the element corresponding to capacitor 63, thereby generating a data record group for one frequency. In this embodiment, the above-described series of processes is performed in increments of 5 kHz within the range of 320 kHz to 370 kHz, thereby generating a data record group for each frequency.

[0051] The temperature characteristic data determination device 1 determines target temperature characteristic data based on an electrical signal output from the output unit 80 of the magnet temperature information output device OD, the electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. To determine the target temperature characteristic data, when the temperature of the temperature sensing element 51 is at room temperature, an AC voltage is applied to the coil 61 while varying the frequency, and an electrical signal corresponding to the frequency of the AC voltage applied to the coil 61 is output from the output unit 80. In this embodiment, the frequency of the AC voltage applied to the coil 61 is varied, for example, according to a frequency stored in the database DB. That is, in this embodiment, an AC signal having a frequency in 5 kHz increments within a range of 320 kHz to 370 kHz is applied to the coil 61. In this embodiment, when an AC voltage is applied to the coil 61, an AC signal is applied to the coil 61 from an AC power source PS.

[0052] In this embodiment, the temperature characteristic data determination device 1 determines an application frequency indicating the frequency of the AC voltage to be applied to the coil 61, and determines the temperature characteristic data corresponding to the determined application frequency as the target temperature characteristic data. For example, the application frequency indicates the frequency of the AC voltage to be applied to the coil 61 when actually obtaining the temperature of the permanent magnet 25 using the magnet temperature information output device OD. Then, the temperature characteristic data determination device 1 transmits the determined target temperature characteristic data to the control circuit 41. By this process, the temperature characteristic data determination device 1 includes the functional elements shown in FIG. 3 . That is, the temperature characteristic data determination device 1 includes an acquisition unit 2, a determination unit 3, and an output unit 4.

[0053] The acquiring unit 2 acquires an electric signal corresponding to the magnitude of the voltage drop occurring in the electric resistance element 70. In this embodiment, the acquiring unit 2 acquires the electric signal corresponding to the frequency of the AC voltage applied to the coil 61 from the output unit 80 of the magnet temperature information output device OD. The acquiring unit 2 transmits the acquired electric signal to the determining unit 3. The determination unit 3 determines the target temperature characteristic data based on the acquired electrical signal. In this embodiment, the determination unit 3 determines the applied frequency based on the electrical signal received from the acquisition unit 2, and determines the temperature characteristic data corresponding to the determined applied frequency as the target temperature characteristic data. The determination unit 3 transmits the determined target temperature characteristic data to the output unit 4. The output unit 4 transmits the target temperature characteristic data received from the determination unit 3 to the control circuit 41.

[0054] Next, the operation of the temperature characteristic data determining device 1 and the temperature characteristic data determining method according to this embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of processing in the temperature characteristic data determining device according to this embodiment. As shown in Fig. 5, in this embodiment, the temperature characteristic data determining method includes steps S11, S12, S13, and S14.

[0055] In step S11, the acquisition unit 2 acquires an electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. As described above, when determining the target temperature characteristic data, when the temperature of the temperature sensing element 51 is at room temperature, an AC voltage is applied to the coil 61 while changing the frequency, and an electrical signal corresponding to the frequency of the AC voltage applied to the coil 61 is output from the output unit 80. Therefore, the acquisition unit 2 acquires the electrical signal corresponding to the frequency of the AC voltage applied to the coil 61. That is, the acquisition unit 2 acquires the electrical signal for each of a plurality of frequencies. Furthermore, in this embodiment, the acquisition unit 2 acquires the AC signal applied to the coil 61 from the AC power supply PS. For example, the acquisition unit 2 acquires a combination of the electrical signal and the AC signal in association with the frequency of the AC voltage applied to the coil 61. In this embodiment, the acquisition unit 2 acquires a combination of the electrical signal and the AC signal in association with the frequency of the AC signal. In this embodiment, the acquisition unit 2 may include, for example, an oscilloscope or a phase detector.

[0056] In step S12, the determination unit 3 determines the applied frequency. The determination unit 3 determines the applied frequency based on the electrical signal acquired in step S11. The determination unit 3 determines the applied frequency so as to correspond to the opposing distance between the coil 53 and the coil 61. In this embodiment, the predetermined resonant frequency corresponding to the opposing distance between the coil 53 and the coil 61 in the magnet temperature information output device OD is determined as the applied frequency. Therefore, in step S12, it can be said that the determination unit 3 determines the predetermined resonant frequency corresponding to the opposing distance between the coil 53 and the coil 61 in the magnet temperature information output device OD.

[0057] In this embodiment, the determination unit 3 determines the application frequency based on the phase difference between the electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70 and the AC signal applied to the coil 61 from the AC power supply PS. In this embodiment, the determination unit 3 determines the application frequency, for example, as follows. First, the determination unit 3 determines the phase difference between the electrical signal and the AC signal for each combination. Then, the determination unit 3 determines, as the application frequency, a frequency associated with a combination in which the determined phase difference falls within a predetermined range. The predetermined range is, for example, between −5 degrees and 5 degrees. If there are multiple combinations in which the determined phase difference falls within the predetermined range, the determination unit 3 may determine, as the application frequency, a frequency associated with the combination in which the phase difference is smallest. As described above, the electrical signal and AC signal associated with each frequency are signals when the temperature of the temperature sensing element 51 is at room temperature. Therefore, it can be said that the determination unit 3 determines, as the application frequency, the frequency of the AC voltage in which the phase difference with the electrical signal falls within a predetermined range when the temperature of the temperature sensing element 51 is at room temperature.

[0058] In step S13, the determination unit 3 determines the temperature characteristic data corresponding to the determined applied frequency as the target temperature characteristic data. The determination unit 3 references the database DB and determines the temperature characteristic data corresponding to the determined applied frequency as the target temperature characteristic data. In this embodiment, the determination unit 3 references the database DB and extracts multiple data records including the determined applied frequency. That is, the determination unit 3 extracts a data record group related to the applied frequency. This determines the target temperature characteristic data. As described above, in this embodiment, a combination of temperature and voltage values ​​in a data record group related to one frequency constitutes the temperature characteristic data corresponding to that frequency. Therefore, in this embodiment, the combination of temperature and voltage values ​​included in the extracted data record group indicates the temperature characteristic data corresponding to the applied frequency.

[0059] The determination unit 3 may perform an interpolation process on the determined target temperature characteristic data. In the interpolation process, for example, a voltage value corresponding to each temperature is estimated at a temperature interval smaller than the temperature interval before the interpolation, and target temperature characteristic data having a smaller temperature interval than before the interpolation is generated. The interpolation process includes, for example, linear interpolation and polynomial interpolation.

[0060] In step S14, the output unit 4 outputs the processing results. The output unit 4 outputs the determined applied frequency and target temperature characteristic data as the processing results. For example, the output unit 4 outputs the target temperature characteristic data to the control circuit 41, and outputs the applied frequency to a display device (not shown). Furthermore, the output unit 4 may store the processing results in a predetermined storage device, or may transmit the processing results to another computer system.

[0061] As described above, this determination method discloses a temperature characteristic data determination method that includes determining an application frequency indicating the frequency of the AC voltage to be applied to coil 61 so as to correspond to the opposing distance between coil 53 and coil 61, and determining, by referring to database DB, the temperature characteristic data corresponding to the application frequency as target temperature characteristic data.

[0062] The temperature characteristic data determination device 1 determines an application frequency indicating the frequency of the AC voltage to be applied to the coil 61 so as to correspond to the opposing distance between the coil 53 and the coil 61, and determines the temperature characteristic data corresponding to the application frequency as the target temperature characteristic data by referring to the database DB.

[0063] The effects of the present determination method and the temperature characteristic data determination device 1 will be described below with reference to Figures 6 and 7. Figures 6 and 7 are diagrams showing the relationship between the temperature and the voltage drop that occurs in an electrical resistance element. In the graphs shown in Figures 6 and 7, the horizontal axis represents temperature [°C], and the vertical axis represents the voltage value [V] based on the electrical signal corresponding to the magnitude of the voltage drop.

[0064] 6, relationship G1 represents temperature characteristic data under the condition that the opposing distance between coil 53 and coil 61 is 3.0 mm and an AC voltage of a predetermined resonance frequency corresponding to the opposing distance of 3.0 mm is applied to coil 61. In other words, relationship G1 represents temperature characteristic data under the condition that the opposing distance between coil 53 and coil 61 and the frequency of the AC voltage applied to coil 53 correspond to each other.

[0065] Relationship G2 shows temperature characteristic data under the condition that the distance between coil 53 and coil 61 is 2.5 mm and an AC voltage of the same frequency as that of relationship G1 is applied to coil 61. Relationship G3 shows temperature characteristic data under the condition that the distance between coil 53 and coil 61 is 3.5 mm and an AC voltage of the same frequency as that of relationship G1 is applied to coil 61. In other words, relationships G2 and G3 show temperature characteristic data under the condition that the distance between coil 53 and coil 61 does not correspond to the frequency of the AC voltage applied to coil 53.

[0066] 7, relationship G4 shows temperature characteristic data obtained under the condition that the distance between coil 53 and coil 61 is 2.5 mm and an AC voltage having a predetermined resonant frequency corresponding to the distance of 2.5 mm is applied to coil 61. Relationship G5 shows temperature characteristic data obtained under the condition that the distance between coil 53 and coil 61 is 3.5 mm and an AC voltage having a predetermined resonant frequency corresponding to the distance of 3.5 mm is applied to coil 61. Relationships G1, G4, and G5 can be obtained, for example, using the equivalent circuit described above.

[0067] When comparing the relationship G2 with the relationship G4, in which the opposing distance between coil 53 and coil 61 is the same, it is clear that the two temperature characteristic data show different changes. Similarly, when comparing the relationship G3 with the relationship G5, it is clear that the two temperature characteristic data show different changes. That is, it is clear that the temperature characteristic data show different changes when the opposing distance between coil 53 and coil 61 and the frequency of the AC voltage applied to coil 61 do not correspond to each other and when the opposing distance and the frequency correspond to each other.

[0068] Furthermore, comparing the relationship G1 with the relationships G2 and G3 reveals that there is a discrepancy between the temperature corresponding to a specific voltage value in the relationship G1 and the temperature corresponding to that voltage value in the relationships G2 and G3. For example, while the temperature corresponding to 2.2 V in the relationship G1 is approximately 140°C, the temperature corresponding to 2.2 V in the relationship G2 is approximately 160°C, and the temperature corresponding to 2.2 V in the relationship G3 is approximately 120°C. Thus, even though the opposing distance between coil 53 and coil 61 and the frequency of the AC voltage applied to coil 61 do not correspond to each other, when the temperature of permanent magnet 25 is obtained using temperature characteristic data under conditions in which the opposing distance and the frequency correspond to each other, a discrepancy occurs between the obtained temperature and the actual temperature.

[0069] In contrast to this, in the present determination method and temperature characteristic data determination device 1, the applied frequency is determined so as to correspond to the opposing distance between the coil 53 and the coil 61, and the temperature characteristic data corresponding to the applied frequency is determined as the target temperature characteristic data. That is, in the present determination method and temperature characteristic data determination device 1, the temperature characteristic data under the condition that the opposing distance between the coil 53 and the coil 61 corresponds to the frequency of the AC voltage applied to the coil 61, is determined as the target temperature characteristic data. Therefore, the present determination method and temperature characteristic data determination device 1 determine appropriate temperature characteristic data.

[0070] In this determination method, determining includes determining as the applied frequency the frequency of the AC voltage whose phase difference with the electrical signal output from the output section 80 is within a predetermined range when the temperature of the temperature-sensing element 51 is at room temperature. When the frequency of the AC voltage that brings the phase difference into a predetermined range is determined as the applied frequency, the frequency that corresponds to the opposing distance between the coils 53 and 61 is reliably determined as the applied frequency.

[0071] Next, a modified example of the operation of the temperature characteristic data determining device 1 and the temperature characteristic data determining method according to the present embodiment will be described. This modified example differs from the above-described embodiment in the process of determining the applied frequency. The following mainly describes the differences between the above-described embodiment and this modified example.

[0072] In step S11 in this modification, the acquiring unit 2 does not acquire the AC signal applied to the coil 61 from the AC power supply PS. The acquiring unit 2 acquires, for example, an electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70 in association with the frequency of the AC voltage applied to the coil 61. In this modification, the acquiring unit 2 may include, for example, a microcomputer or an oscilloscope.

[0073] In step S12 of this modified example, the determination unit 3 determines the application frequency based on a value based on the electrical signal. In this modified example, the determination unit 3 also determines the application frequency so as to correspond to the opposing distance between the coil 53 and the coil 61. In this modified example, the determination unit 3 determines the application frequency as follows. First, the determination unit 3 calculates a value based on the electrical signal at each frequency. The value based on the electrical signal includes, for example, a voltage value. Then, the determination unit 3 determines the frequency associated with the electrical signal at which the calculated value becomes an extreme value as the application frequency. In this modified example, the electrical signal associated with each frequency is the electrical signal when the temperature of the temperature sensing element 51 is at room temperature. Therefore, in this modified example, the determination unit 3 determines the frequency at which the value based on the electrical signal output from the output unit 80 becomes an extreme value when the temperature of the temperature sensing element 51 is at room temperature as the application frequency.

[0074] In this modified example, determining includes determining, as the applied frequency, the frequency at which the value based on the electrical signal output from the output section 80 becomes an extreme value when the temperature of the temperature sensing element 51 is at room temperature. When the frequency at which the value based on the voltage signal becomes an extreme value is determined as the applied frequency, the frequency corresponding to the opposing distance between the coils 53 and 61 is reliably determined as the applied frequency.

[0075] Next, another modified example of the operation of the temperature characteristic data determination device 1 and the temperature characteristic data determination method according to this embodiment will be described with reference to Figs. 8 and 9. Fig. 8 is a diagram showing another example of a database. Fig. 9 is a flowchart showing another example of processing in the temperature characteristic data determination device according to this embodiment. This modified example differs from the above-described embodiment in terms of the data structure of the information stored in the database DB and the processing for determining the target temperature characteristic data. Below, the differences between the above-described embodiment and this modified example will be mainly described.

[0076] In this modification, the database DB stores information indicating the correspondence between the facing distance between the coil 53 and the coil 61 and the temperature characteristic data. In the example shown in FIG. 8, each data record of the information indicating the correspondence between the facing distance and the temperature characteristic data includes, as data items, a data ID, a temperature, and a voltage value. The data ID is an identifier that uniquely identifies each piece of temperature characteristic data, and one data ID is assigned according to the facing distance between the coil 53 and the coil 61. In this modification, the combination of the temperature and the voltage value in the data record group related to one data ID constitutes the temperature characteristic data corresponding to that data ID. In other words, in this modification as well, the database DB stores multiple pieces of temperature characteristic data.

[0077] In this modification, a data record of information indicating the correspondence between frequency and temperature characteristic data is generated using, for example, an equivalent circuit similar to that in the above-described embodiment. In this modification, each data record group is generated, for example, as follows. First, an element corresponding to AC power supply PS is set as a power supply that applies an AC voltage to an element corresponding to coil 61, the AC voltage having a frequency lower than the predetermined resonant frequency that excites coil 53. Then, while changing the temperature of the element corresponding to temperature sensor 51, a voltage value across the element corresponding to capacitor 63 is acquired as a value corresponding to the voltage drop occurring in the element corresponding to electrical resistance element 70. Then, a data ID is associated with the temperature corresponding to temperature sensor 51 and the acquired voltage value across the element corresponding to capacitor 63, thereby generating a data record group for one data ID. In this modification, the above-described series of processes is performed while changing the coupling constant of the element corresponding to the magnetic coupling between coil 53 and coil 61. The coupling constant of the element corresponding to the magnetic coupling between coil 53 and coil 61 depends on the opposing distance between coil 53 and coil 61. Therefore, by performing the above-described series of processes, a data record group for each data ID is generated.

[0078] In this modification, as in the above-described embodiment, the temperature characteristic data determination device 1 determines the target temperature characteristic data based on an electrical signal output from the output unit 80 of the magnet temperature information output device OD, the electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. Meanwhile, in this modification, when determining the target temperature characteristic data, an AC voltage having a frequency lower than the predetermined resonant frequency for exciting the coil 53 is applied to the coil 61. In this modification, when the temperature of the temperature sensing element 51 is at a predetermined temperature, an AC voltage having the frequency is applied to the coil 61. That is, the determination method in this modification includes applying an AC voltage having a frequency lower than the predetermined resonant frequency for exciting the coil 53 to the coil 61 when the temperature of the temperature sensing element 51 is at the predetermined temperature. The difference between the frequency of the AC voltage applied to the coil 61 and the predetermined resonant frequency may be 5 kHz or more and 30 kHz or less. The predetermined temperature is, for example, room temperature. Thus, in this modification, unlike the above-described embodiment, the frequency of the AC voltage applied to the coil 61 is not changed when determining the target temperature characteristic data.

[0079] As shown in FIG. 9, in this modification, the temperature characteristic data determination method further includes steps S21, S22, and S23. In step S21, the acquiring unit 2 acquires an electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. As described above, in this modification, when determining the target temperature characteristic data, an AC voltage having a frequency lower than the predetermined resonance frequency for exciting the coil 53 is applied to the coil 61. Therefore, in this modification, the acquiring unit 2 acquires an electrical signal output from the output unit 80 by applying an AC voltage having a frequency lower than the predetermined resonance frequency for exciting the coil 53 to the coil 61. In this modification, the acquiring unit 2 may include, for example, a microcomputer or an oscilloscope.

[0080] In step S22, the determination unit 3 determines target temperature characteristic data based on the acquired electrical signal. In this modification, the determination unit 3 refers to the database DB and determines, as the target temperature characteristic data, temperature characteristic data whose voltage value at the predetermined temperature corresponds to the value based on the acquired electrical signal.

[0081] In this modification, the determination unit 3 determines the target temperature characteristic data, for example, as follows. First, the determination unit 3 determines a value based on the acquired electrical signal. Then, the determination unit 3 refers to the database DB and compares each of the voltage values ​​at the predetermined temperature in each data record group with the determined value. Then, the determination unit 3 determines which of the voltage values ​​corresponds to the determined value. For example, the determination unit 3 may determine that a specific voltage value corresponds to the determined value if the specific voltage value matches the determined value, or may determine that a specific voltage value corresponds to the determined value if the difference between the specific voltage value and the determined value is equal to or less than a predetermined threshold. Then, the determination unit 3 extracts multiple data records including a data ID associated with the voltage value determined to correspond to the determined value. In this way, the target temperature characteristic data is determined.

[0082] In step S23, the output unit 4 outputs the processing result. The output unit 4 outputs the determined target temperature characteristic data as the processing result. For example, the output unit 4 outputs the target temperature characteristic data to the control circuit 41. Furthermore, the output unit 4 may store the processing result in a predetermined storage device or may transmit the processing result to another computer system.

[0083] This modified example discloses a method for determining temperature characteristic data, which includes applying an AC voltage to coil 61 when the temperature-sensing element 51 is at a predetermined temperature, the AC voltage having a frequency lower than a predetermined resonant frequency that excites coil 53, acquiring an electrical signal output from output unit 80 by said application, and referring to database DB, determining, as target temperature characteristic data, temperature characteristic data that corresponds to a value based on the acquired electrical signal, which value is based on the electrical signal corresponding to the magnitude of voltage drop at the predetermined temperature.

[0084] In this modification, when the temperature sensing element 51 is at a predetermined temperature, the temperature characteristic data determination device 1 applies to the coil 61 an AC voltage having a frequency lower than a predetermined resonance frequency that excites the coil 53, thereby obtaining an electrical signal output from the output unit 80. The temperature characteristic data determination device 1 refers to the database DB and determines, as the target temperature characteristic data, temperature characteristic data in which a value based on the obtained electrical signal corresponds to a value based on the electrical signal that corresponds to the magnitude of the voltage drop at the predetermined temperature.

[0085] Relationship G1 shows temperature characteristic data under the condition that the opposing distance between coil 53 and coil 61 is 3.0 mm and an AC voltage having a frequency corresponding to the opposing distance of 3.0 mm is applied to coil 61. In other words, relationship G1 shows temperature characteristic data under the condition that the opposing distance between coil 53 and coil 61 and the frequency of the AC voltage applied to coil 53 correspond to each other.

[0086] The effects of the temperature characteristic data determining method and the temperature characteristic data determining device 1 according to this modification will be described below with reference to Figs. 6, 7, and 10. Fig. 10 is a diagram showing the relationship between the temperature and an electrical signal corresponding to a voltage drop occurring in an electrical resistance element. In the graph shown in Fig. 10, the horizontal axis represents temperature [°C], and the vertical axis represents a voltage value [V] based on an electrical signal corresponding to the magnitude of the voltage drop.

[0087] In FIG. 10, relationship G6 represents temperature characteristic data obtained under the condition that the distance between coil 53 and coil 61 is 3.0 mm and an AC voltage having a frequency 20 kHz lower than the predetermined resonance frequency corresponding to the distance of 3.0 mm is applied to coil 61. Relationship G7 represents temperature characteristic data obtained under the condition that the distance between coil 53 and coil 61 is 2.5 mm and an AC voltage having the same frequency as that of relationship G6 is applied to coil 61. Relationship G8 represents temperature characteristic data obtained under the condition that the distance between coil 53 and coil 61 is 3.5 mm and an AC voltage having the same frequency as that of relationship G6 is applied to coil 61. That is, relationships G6 to G8 represent temperature characteristic data obtained under the condition that the frequency of the AC voltage applied to coil 61 is lower than the predetermined resonance frequency. Relationships G6 to G8 can be obtained, for example, using the equivalent circuit described above.

[0088] Comparing the relationships G1 to G5 with the relationships G6 to G8, we see that, for example, in the range of 20°C to 80°C, the difference in voltage values ​​between the relationships G6 to G8 is greater than the difference in voltage values ​​between the relationships G1 to G5. Particularly at room temperature, the difference in voltage values ​​between the relationships G6 to G8 is greater than the difference in voltage values ​​between the relationships G1 to G5. That is, when the frequency of the AC voltage applied to the coil 61 is lower than a predetermined resonant frequency, the difference in voltage values ​​at the predetermined temperature in each temperature characteristic data tends to increase. Therefore, when the frequency of the AC voltage applied to the coil 61 is lower than a predetermined resonant frequency, the temperature characteristic data for the combination of the opposing distance between the coils 53 and 61 and the frequency is easily identified based on a value based on an electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature. When the temperature characteristic data for the combination of the opposing distance and frequency is used to obtain the temperature of a portion of the rotor 20, there is little discrepancy between the obtained temperature and the actual temperature.

[0089] In this modification, when the temperature sensitive element 51 is at a predetermined temperature, an AC voltage having a frequency lower than a predetermined resonant frequency for exciting the coil 53 is applied to the coil 61, thereby acquiring an electrical signal output from the output unit 80. The database DB is referenced, and a value based on the electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature, that is, temperature characteristic data corresponding to the value based on the acquired electrical signal, is determined as the target temperature characteristic data. That is, in this modification, temperature characteristic data corresponding to the combination of the opposing distance between the coil 53 and the coil 61 and the frequency of the AC voltage applied to the coil 61 is determined as the target temperature characteristic data. Therefore, the temperature characteristic data determination method and temperature characteristic data determination device 1 in this modification determine appropriate temperature characteristic data.

[0090] Second Embodiment A temperature characteristic data determination device 1 that executes a temperature characteristic data determination method according to this embodiment will be described with reference to Fig. 3 and Fig. 11. Fig. 11 is a schematic diagram showing the configuration of a temperature characteristic data acquisition device. This embodiment differs from the first embodiment described above mainly in terms of the processing of the acquisition unit 2 in the temperature characteristic data determination device 1. The following mainly describes the differences between this embodiment and the first embodiment.

[0091] As described above, when obtaining the temperature of the permanent magnet 25, the temperature characteristic data stored in the database DB is referenced, and the temperature corresponding to the output electrical signal is obtained as the temperature of the permanent magnet 25. In this embodiment, a temperature characteristic data acquisition device 200 is used to generate the temperature characteristic data. The temperature characteristic data acquisition device 200 is used to generate the temperature characteristic data and is a device different from the rotating electric machine MT. In this embodiment, as shown in FIG. 11 , the temperature characteristic data acquisition device 200 is similar to the rotating electric machine MT, and includes a stator 210 and a rotor 220 instead of the stator 10 and the rotor 20. The rotor 220 is located inside the stator 210. As described above, in the example shown in FIG. 11 , the temperature characteristic data acquisition device 200 is similar to the rotating electric machine MT, but in other examples, the temperature characteristic data acquisition device 200 may have a simpler configuration than the rotating electric machine MT. In the other example, the temperature characteristic data acquisition device 200 may include, for example, two metal plates facing each other.

[0092] The rotor 220 includes a shaft 221, a rotor core 223, and a plurality of permanent magnets 25. The rotor 220 may have a region that serves as a flux barrier. The rotor 220 may also have a region that serves as a flux barrier. The shaft 221 and the rotor core 223 are generally similar to the shaft 21 and the rotor core 23 described above. The shaft 221 and the rotor core 223 may differ from the shaft 21 and the rotor core 23, for example, in terms of their shape and material. The stator 210 includes a cylindrical stator core (not shown) that is arranged to surround the outer periphery of the rotor 220, and a plurality of stator coils.

[0093] When generating temperature characteristic data using the rotating electric machine MT itself, it is necessary to accurately manage the temperature of the entire rotating electric machine MT, but such management is difficult. This problem becomes particularly pronounced when the rotating electric machine MT is large. When the rotating electric machine MT is large, the rotating electric machine MT may include, for example, an automotive motor. In consideration of this problem, in this embodiment, temperature characteristic data is generated using a temperature characteristic data acquisition device 200, which is a device different from the rotating electric machine MT. However, when generating temperature characteristic data using the temperature characteristic data acquisition device 200, the relationship between the temperature and the value based on the electrical signal corresponding to the magnitude of the voltage drop in the rotating electric machine MT must correspond to the relationship between the temperature and the value based on the electrical signal corresponding to the magnitude of the voltage drop in the temperature characteristic data acquisition device 200. If the relationship between the rotating electric machine MT and the temperature characteristic data acquisition device 200 does not correspond to each other, the relationship indicated by the generated temperature characteristic data will be unlikely to correspond to the relationship between the rotating electric machine MT. Therefore, if temperature characteristic data indicating a relationship that does not correspond to the above relationship in the rotating electric machine MT is stored in the database DB, there is a risk that appropriate temperature characteristic data will not be determined as the target temperature characteristic data when obtaining the temperature of the permanent magnet 25 by referring to the database DB.

[0094] Here, the correspondence between the above relationship in the rotating electric machine MT and the above relationship in the temperature characteristic data acquisition device 200 is reflected in the composite impedance of coils 53 and 61 when coils 53 and 61 are magnetically coupled. In this embodiment, the composite impedance in the magnet temperature information output device OD attached to the temperature characteristic data acquisition device 200 is adjusted to a value corresponding to the composite impedance in the magnet temperature information output device OD attached to the rotating electric machine MT. In this embodiment, the above relationship in the temperature characteristic data acquisition device 200 is thereby made to correspond to the above relationship in the rotating electric machine MT.

[0095] The composite impedance of the coil 53 and the coil 61 changes depending on the configuration of the object to which the magnet temperature information output device OD is attached. Therefore, in this embodiment, the configuration of the temperature characteristic data acquisition device 200 is changed to adjust the composite impedance in the magnet temperature information output device OD attached to the temperature characteristic data acquisition device 200. In this way, by generating temperature characteristic data using the temperature characteristic data acquisition device 200 whose composite impedance has been adjusted, it is possible to prevent temperature characteristic data indicating a relationship that does not correspond to the above-mentioned relationship in the rotating electric machine MT from being stored in the database DB.

[0096] When generating temperature characteristic data using the temperature characteristic data acquisition device 200, the temperature characteristic data determination device 1 generates the temperature characteristic data and stores the generated temperature characteristic data in the database DB. In this embodiment, the acquisition unit 2 shown in Fig. 3 acquires the composite impedance of the coil 53 and the coil 61 and generates the temperature characteristic data. Furthermore, the acquisition unit 2 stores the generated temperature characteristic data in the database DB.

[0097] Next, with reference to Figs. 11 to 14, another example of the operation of the temperature characteristic data determining device 1 will be described, along with the generation of temperature characteristic data in the temperature characteristic data determining method according to this embodiment. Fig. 12 is a flowchart showing the temperature characteristic data determining method according to this embodiment. Fig. 13 is a diagram showing the relationship between the frequency of an AC voltage and the first synthetic impedance. Fig. 14 is a flowchart showing the procedure for adjusting the second synthetic impedance. As shown in Fig. 12, in this embodiment, the temperature characteristic data determining method includes steps S31, S32, S33, S34, S35, S36, and S37 as steps related to the generation of temperature characteristic data.

[0098] In step S31, the element unit 50 and the element unit 60 are attached to the rotating electric machine MT. For example, similar to the first embodiment described above, the element unit 50 is attached to the rotor 20, and the element unit 60 is attached to the stator 10. The temperature sensor 51 may be attached to at least one of the multiple permanent magnets 25, and the coil 53 may be electrically connected to the temperature sensor 51. The coil 61 is attached to the stator 10. Hereinafter, the "state in which the element unit 50 is attached to the rotor 20 and the element unit 60 is attached to the stator 10" may be referred to as the "first state."

[0099] In step S32, a first total impedance is acquired. In step S32, the first total impedance is the total impedance of the coils 53 and 61 when, in the first state, an AC voltage is applied to the coil 61, the coils 53 and 61 are magnetically coupled, and the temperature sensing element 51 is at a predetermined temperature. In this embodiment, the first total impedance is acquired as follows. First, in the first state, an AC voltage is applied to the coil 61 from the AC power supply PS to magnetically couple the coils 53 and 61. The AC voltage is applied to the coil 61, for example, with the coils 53 and 61 facing each other. Then, the temperature sensing element 51 is heated to a predetermined temperature. The predetermined temperature is, for example, room temperature. In this embodiment, the predetermined temperature is 25°C. Then, the first total impedance is measured. For example, the impedance across the electrical resistance element 70 in FIG. 2 is measured as the first total impedance. The measurement of the first composite impedance may be performed by, for example, an impedance analyzer or a vector network analyzer (VNA). The vector network analyzer includes, for example, a NaNoVNA. The measured first composite impedance is transmitted to the acquisition unit 2 of the temperature characteristic data determination device 1. As a result, the acquisition unit 2 acquires the first composite impedance.

[0100] In step S32, the frequency of the AC voltage applied to the coil 61 may be a frequency at which the first total impedance is maximized. FIG. 13 shows an example of the relationship between the frequency of the AC voltage applied to the coil 61 and the first total impedance. In the graph shown in FIG. 13, the horizontal axis represents frequency [Hz] and the vertical axis represents first total impedance [Ω]. As shown in FIG. 13, the first total impedance varies depending on the frequency of the AC voltage applied to the coil 61. In FIG. 13, the maximum value of the first total impedance is illustrated as impedance Zmax, and the frequency at which the first total impedance becomes impedance Zmax is illustrated as frequency Fmax. In this embodiment, the frequency of the AC voltage applied to the coil 61 is frequency Fmax. That is, in this embodiment, an AC voltage at which the first total impedance becomes maximum is applied to the coil 61.

[0101] In step S33, the element unit 50 and the element unit 60 are removed from the rotating electric machine MT. The element unit 50 is removed from the rotor 20, and the element unit 60 is removed from the stator 10. In this manner, in this embodiment, the element unit 50 and the element unit 60 are configured to be removable from the rotating electric machine MT.

[0102] In step S34, the element unit 50 and the element unit 60 are attached to the temperature characteristic data acquisition device 200. The element unit 50 is attached to the rotor 220, and the element unit 60 is attached to the stator 210. The element units 50 and 60 are attached to the temperature characteristic data acquisition device 200 in the same manner as the element units 50 and 60 are attached to, for example, a rotating electric machine MT. That is, the temperature sensor 51 is attached to at least one permanent magnet 25 of the multiple permanent magnets 25 of the rotor 220, and the coil 53 is electrically connected to the temperature sensor 51. The coil 61 is attached to the stator 210. Hereinafter, the "state in which the element units 50 and the element units 60 are attached to the temperature characteristic data acquisition device 200" may be referred to as the "second state."

[0103] In step S35, the second total impedance is adjusted to a value corresponding to the first total impedance. In step S35, the second total impedance is the total impedance of coil 53 and coil 61 when, in the second state, an AC voltage is applied to coil 61, coil 53 and coil 61 are magnetically coupled, and the temperature sensing element is at a predetermined temperature. In this embodiment, as shown in FIG. 15 , step S35 includes steps S351, S352, and S353.

[0104] In step S351, the second composite impedance is acquired. In this embodiment, the second composite impedance is acquired as follows. First, in the second state, an AC voltage is applied to the coil 61 from the AC power supply PS to magnetically couple the coils 53 and 61. The AC voltage is applied to the coil 61, for example, while the coils 53 and 61 are facing each other. Then, the temperature sensing element 51 is heated to a predetermined temperature. In this embodiment, the predetermined temperature is the temperature to which the temperature sensing element 51 is heated in step S32. Then, the second composite impedance is measured. The second composite impedance is measured, for example, in the same manner as the measurement of the first composite impedance. The measured second composite impedance is transmitted to the acquisition unit 2 of the temperature characteristic data determination device 1. As a result, the acquisition unit 2 acquires the second composite impedance.

[0105] Like the first composite impedance, the second composite impedance also changes depending on the frequency of the AC voltage applied to the coil 61. In step S351, the frequency of the AC voltage applied to the coil 61 may be the same as the frequency of the AC voltage applied to the coil 61 in step S32. In step S351, the frequency of the AC voltage applied to the coil 61 may be different from the frequency of the AC voltage applied to the coil 61 in step S32. If the frequency of the AC voltage in step S351 is different from the frequency of the AC voltage in step 32, the frequency of the AC voltage in step S351 may be within a range of 90% to 110% of the frequency of the AC voltage in step 32. Alternatively, the frequency of the AC voltage in step S351 may be within a range of 95% to 105% of the frequency of the AC voltage in step 32.

[0106] In step S352, the acquisition unit 2 determines whether the second composite impedance is within a predetermined range. The acquisition unit 2 determines whether the second composite impedance is a value corresponding to the first composite impedance. In this embodiment, the acquisition unit 2 determines whether the second composite impedance is a value within a range of 95% to 105% of the first composite impedance. The acquisition unit 2 may also determine whether the second composite impedance is a value within a range of 98% to 102% of the first composite impedance. If it is determined that the second composite impedance is within the predetermined range, the process proceeds to step S36. If it is determined that the second composite impedance is not within the predetermined range, the process proceeds to step S353.

[0107] In step S353, the configuration of the temperature characteristic data acquisition device 200 is changed. In step S353, the configuration of the temperature characteristic data acquisition device 200, for example, the configuration of the rotor 220, is changed. The configuration of the rotor 220 includes, for example, the shape and material of the rotor 220, and the presence and shape of a flux barrier. In this embodiment, the configuration of the temperature characteristic data acquisition device 200 is changed so that the second composite impedance acquired in step S351 falls within a predetermined range in step S352.

[0108] In this way, in steps S351 to S353, the acquisition of the second synthetic impedance, the determination of the second synthetic impedance, and the change of the configuration of the temperature characteristic data acquisition device 200 are repeated until the second synthetic impedance reaches a value corresponding to the first synthetic impedance. As described above, in step S352, it is determined whether the second synthetic impedance is a value corresponding to the first synthetic impedance. Therefore, in step S35, the second synthetic impedance is adjusted to a value corresponding to the first synthetic impedance. In this embodiment, it is determined whether the second synthetic impedance is a value within a range of 95% to 105% of the first synthetic impedance, and therefore, in step S35, the second synthetic impedance is adjusted to a value within a range of 95% to 105% of the first synthetic impedance.

[0109] In step S36, the acquisition unit 2 generates temperature characteristic data. In this embodiment, an AC voltage is applied to the coil 61 in the second state, and an electrical signal generated in the electrical resistance element 70 is output while changing the temperature of the temperature sensing element 51, thereby generating the temperature characteristic data. In this embodiment, the temperature characteristic data is generated, for example, as follows. First, in the second state, an AC voltage is applied to the coil 61 from the AC power supply PS. At this time, information indicating the frequency of the AC voltage applied to the coil 61 is transmitted to the acquisition unit 2. Then, an electrical signal generated in the electrical resistance element 70 is output while changing the temperature of the temperature sensing element 51. Then, the output electrical signal and the temperature corresponding to the electrical signal are transmitted to the acquisition unit 2. Then, the acquisition unit 2 generates temperature characteristic data by using a combination of a value based on the acquired electrical signal and a temperature corresponding to the electrical signal as one data record.

[0110] In step S37, the acquisition unit 2 stores the temperature characteristic data in the database DB. The acquisition unit 2 stores the frequency and the temperature characteristic data in the database DB in association with each other. In this embodiment, the acquisition unit 2 stores the frequency of the AC voltage applied to the coil 61 in step S36 and the temperature characteristic data generated in step S36 in the database DB in association with each other.

[0111] In this embodiment, after step S35, steps S36 and S37 may be repeatedly performed while changing the frequency of the AC voltage applied to the coil 61. As a result, for each of a plurality of frequencies, the frequency and temperature characteristic data are associated with each other and stored in the database DB. Steps S36 and S37 may be performed, for example, in increments of 5 kHz within a range of 320 kHz to 370 kHz.

[0112] In the present embodiment, step S36 and step S37 do not have to be performed repeatedly. When step S36 and step S37 are not performed repeatedly, for example, an AC voltage that maximizes the first composite impedance may be applied to the coil 61 in step S36. In step S37, the acquisition unit 2 may store in the database DB the frequency of the AC voltage that maximizes the first composite impedance and the temperature characteristic data generated in step S36 in association with each other. That is, when step S36 and step S37 are not performed repeatedly, only the temperature characteristic data associated with the frequency of the AC voltage that maximizes the first composite impedance may be stored in the database DB.

[0113] In the above-described temperature characteristic data determination method, after the element units 50 and 60 are removed from the rotating electric machine MT in step S33, the element units 50 and 60 are attached to the temperature characteristic data acquisition device 200 in step S34. However, the element units 50 and 60 do not have to be removed from the rotating electric machine MT. That is, the temperature characteristic data determination method does not have to include step S33 as a process related to the generation of temperature characteristic data. If the temperature characteristic data determination method does not include step S33, another element unit 50 and element unit 60 having similar characteristics to the element unit 50 and element unit 60 attached to the rotating electric machine MT may be attached to the temperature characteristic data acquisition device 200 in step S34.

[0114] Next, the determination of temperature characteristic data in the temperature characteristic data determination method according to this embodiment will be described with reference to Fig. 15. Fig. 15 is a flowchart showing the temperature characteristic data determination method according to this embodiment. As shown in Fig. 15, in this embodiment, the temperature characteristic data determination method includes steps S41, S42, S43, S44, and S45 as steps related to the determination of target temperature characteristic data.

[0115] In step S41, the element unit 50 and the element unit 60 are reattached to the rotating electric machine MT. The element unit 50 is attached to the rotor 20, and the element unit 60 is attached to the stator 10. In step S41, similar to step S31, the element unit 50 is attached to the rotor 20, and the element unit 60 is attached to the stator 10.

[0116] In step S42, the acquiring unit 2 acquires an electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70. In step S42, the acquiring unit 2 acquires the electrical signal corresponding to the magnitude of the voltage drop occurring in the electrical resistance element 70, for example, in the same manner as in step S11. That is, in step S42, the acquiring unit 2 acquires a combination of an electrical signal corresponding to the frequency of the AC voltage applied to the coil 61 and the AC signal applied to the coil 61, in association with the frequency of the AC voltage applied to the coil 61. In the present embodiment, the acquiring unit 2 acquires the combination of the electrical signal and the AC signal in association with the frequency of the AC signal.

[0117] In step S43, the determination unit 3 determines the applied frequency. The determination unit 3 determines the applied frequency based on the electrical signal acquired in step S42. The determination unit 3 determines the applied frequency so as to correspond to the opposing distance between coil 53 and coil 61 in the first state. In step S43, the determination unit 3 determines the applied frequency in the same manner as in step S12, for example. That is, in step S43, the determination unit 3 determines the applied frequency based on the phase difference between the electrical signal corresponding to the magnitude of the voltage drop occurring in electrical resistance element 70 and the AC signal applied to coil 61 from AC power supply PS.

[0118] In step S44, the temperature characteristic data corresponding to the determined applied frequency is determined as the target temperature characteristic data. The determination unit 3 refers to the database DB that stores the temperature characteristic data generated through the processes of steps S31 to S37 described above, and determines the temperature characteristic data corresponding to the determined applied frequency as the target temperature characteristic data. In step S44, the determination unit 3 determines the target temperature characteristic data in the same manner as in step S13, for example. That is, the determination unit 3 refers to the database DB, extracts a plurality of data records including the determined applied frequency, and determines the target temperature characteristic data.

[0119] In step S45, the output unit 4 outputs the processing result. In step S45, the output unit 4 outputs the processing result, for example, in the same manner as in step S14. That is, the output unit 4 outputs the determined applied frequency and target temperature characteristic data as the processing result.

[0120] As described above, the determination method according to the second embodiment discloses a temperature characteristic data determination method including: acquiring a first composite impedance; adjusting a second composite impedance to a value corresponding to the first composite impedance; generating temperature characteristic data after the adjustment; and storing the temperature characteristic data in a database DB. In this temperature characteristic data determination method, the generating includes applying an AC voltage to the coil 61 in the second state and outputting an electrical signal while changing the temperature of the temperature sensing element 51 to generate temperature characteristic data. The storing includes storing the frequency of the AC voltage applied to the coil 61 and the generated temperature characteristic data in the database DB in association with each other.

[0121] In the determination method according to the second embodiment, temperature characteristic data is generated after the second synthetic impedance is adjusted to a value corresponding to the first synthetic impedance. The correspondence between the relationship between the temperature and a value based on an electrical signal corresponding to the magnitude of the voltage drop in the rotating electric machine MT and the relationship between the temperature and a value based on an electrical signal corresponding to the magnitude of the voltage drop in the temperature characteristic data acquisition device 200 can be reflected in the correspondence between the first synthetic impedance and the second synthetic impedance. That is, in this determination method, by adjusting the second synthetic impedance to a value corresponding to the first synthetic impedance, the above relationship in the temperature characteristic data acquisition device 200 corresponds to the above relationship in the rotating electric machine MT. Therefore, in this determination method, temperature characteristic data is generated in a state in which the above relationship in the temperature characteristic data acquisition device 200 corresponds to the above relationship in the rotating electric machine MT. As a result, temperature characteristic data indicating a relationship that does not correspond to the above relationship in the rotating electric machine MT is prevented from being stored in the database DB. Based on the above, this determination method determines appropriate temperature characteristic data.

[0122] In this determination method, adjusting includes adjusting the second composite impedance to a value within a range of 95% to 105% of the first composite impedance. When the second synthetic impedance is adjusted to a value within a range of 95% to 105% of the first synthetic impedance, the temperature characteristic data is generated in a state in which the above relationship in the temperature characteristic data acquisition device 200 more closely corresponds to the above relationship in the rotating electric machine MT. Therefore, when the second synthetic impedance is adjusted to the above value, more appropriate temperature characteristic data is determined.

[0123] This determination method includes determining an applied frequency corresponding to the opposing distance between coil 53 and coil 61 in the first state, and determining the temperature characteristic data corresponding to the applied frequency as the target temperature characteristic data by referring to database DB. As described above, the database DB stores temperature characteristic data generated in a state where the above relationship in the temperature characteristic data acquisition device 200 corresponds to the above relationship in the rotating electric machine MT. Therefore, temperature characteristic data showing a relationship that does not correspond to the above relationship in the rotating electric machine MT is prevented from being determined as the target temperature characteristic data, and appropriate temperature characteristic data is reliably determined.

[0124] In this determination method, similarly to the first embodiment described above, the applied frequency is determined so as to correspond to the opposing distance between the coil 53 and the coil 61, and the temperature characteristic data corresponding to the applied frequency is determined as the target temperature characteristic data. Therefore, in this determination method, the temperature characteristic data under the condition that the opposing distance between the coil 53 and the coil 61 corresponds to the frequency of the AC voltage applied to the coil 61 is determined as the target temperature characteristic data. From the above, this determination method determines more appropriate temperature characteristic data.

[0125] The correspondence between the above relationship in the rotating electric machine MT and the above relationship in the temperature characteristic data acquisition device 200 affects the accuracy of the output temperature information. For example, if temperature characteristic data indicating a relationship that does not correspond to the above relationship in the rotating electric machine MT is determined as the target temperature characteristic data, there is a risk that a discrepancy will occur between the obtained temperature and the actual temperature when obtaining the temperature of the permanent magnet 25. In contrast, the present determination method prevents temperature characteristic data indicating a relationship that does not correspond to the above relationship in the rotating electric machine MT from being stored in the database DB, as described above. Therefore, the present determination method can improve the accuracy of the temperature information output from the magnet temperature information output device OD.

[0126] Next, an experiment conducted by the present inventors will be described to demonstrate that more appropriate temperature characteristic data can be determined by adjusting the second synthetic impedance to a value within a range of 95% to 105% of the first synthetic impedance.

[0127] The inventors conducted the following experiment. In this experiment, two rotating electric machines were first prepared. The two rotating electric machines had different configurations and a configuration similar to that of the rotating electric machine MT. Hereinafter, to distinguish between these two rotating electric machines, one rotating electric machine may be referred to as the first rotating electric machine and the other rotating electric machine may be referred to as the second rotating electric machine. Then, the element unit 50 and the element unit 60 were attached to the first rotating electric machine, and a first composite impedance of the first rotating electric machine was acquired. The acquired first composite impedance of the first rotating electric machine was 819 Ω. Herein, the attachment of the element unit 50 and the element unit 60 to the first rotating electric machine and the acquisition of the first composite impedance of the first rotating electric machine were performed in the same manner as in steps S31 and S32. Then, the element unit 50 and the element unit 60 were removed from the first rotating electric machine.

[0128] The element unit 50 and the element unit 60 removed from the first rotating electric machine were attached to a second rotating electric machine, and the first composite impedance of the second rotating electric machine was obtained. The obtained first composite impedance of the second rotating electric machine was 772 Ω. Here, the attachment of the element unit 50 and the element unit 60 to the second rotating electric machine and the acquisition of the first composite impedance of the second rotating electric machine were performed in the same manner as in steps S31 and S32. In this experiment, the frequency of the AC voltage applied to the coil 61 when acquiring the first composite impedance of the second rotating electric machine was the same as the frequency of the AC voltage applied to the coil 61 when acquiring the first composite impedance of the first rotating electric machine. Then, the element unit 50 and the element unit 60 were removed from the second rotating electric machine.

[0129] The element unit 50 and the element unit 60 removed from the second rotating electric machine were attached to the temperature characteristic data acquisition device 200, and the second synthetic impedance was adjusted. In this experiment, the second synthetic impedance was adjusted to a value that was 93.1% of the first synthetic impedance in the first rotating electric machine and 98.8% of the first synthetic impedance in the second rotating electric machine. That is, in this experiment, the second synthetic impedance was adjusted to 763 Ω.

[0130] In this experiment, the second composite impedance was adjusted by changing the position of the metal member disposed around coil 53 or coil 61 in temperature characteristic data acquisition device 200. In this experiment, the frequency of the AC voltage applied to coil 61 when adjusting the second composite impedance was the same as the frequency of the AC voltage applied to coil 61 when acquiring the first composite impedance of the first rotating electric machine.

[0131] Then, after the second composite impedance was adjusted, temperature characteristic data was generated in the temperature characteristic data acquisition device 200. The generation of the temperature characteristic data in the temperature characteristic data acquisition device 200 was performed in the same manner as in step S36. In this experiment, the frequency of the AC voltage applied to the coil 61 when generating the temperature characteristic data was the same as the frequency of the AC voltage applied to the coil 61 when adjusting the second composite impedance.

[0132] The temperature characteristic data generated by the above-described experiment is shown in FIG. 16. Furthermore, FIG. 16 also shows the temperature characteristic data for the first rotating electric machine and the temperature characteristic data for the second rotating electric machine. FIG. 16 is a diagram showing the relationship between the temperature and the electrical signal corresponding to the voltage drop occurring in the electrical resistance element. In the graph shown in FIG. 16, the horizontal axis represents temperature [°C], and the vertical axis represents the voltage value [V] based on the electrical signal corresponding to the magnitude of the voltage drop.

[0133] In FIG. 16, relationship G9 represents the temperature characteristic data in the temperature characteristic data acquisition device 200 in this experiment. Relationship G10 represents the temperature characteristic data in the first rotating electric machine. Relationship G11 represents the temperature characteristic data in the second rotating electric machine. Comparing relationships G9 to G11, it can be seen that the difference between relationship G9 and relationship G11 is smaller than the difference between relationship G9 and relationship G10. As described above, the second synthetic impedance is 93.1% of the first synthetic impedance in the first rotating electric machine and 98.8% of the first synthetic impedance in the second rotating electric machine. Therefore, it can be seen that by adjusting the second synthetic impedance to a value within the range of 95% to 105% of the first synthetic impedance, the relationship in the temperature characteristic data acquisition device 200 more closely corresponds to the relationship in the rotating electric machine.

[0134] The above describes embodiments and modifications of the present invention, but the present invention is not necessarily limited to the above-described embodiments and modifications, and various modifications are possible without departing from the spirit of the present invention.

[0135] In the above-described embodiment and modified example, the temperature information output device to which the temperature characteristic data determination method and temperature characteristic data determination device 1 are applied is the magnet temperature information output device OD that outputs temperature information related to the temperature of the permanent magnet 25. However, the part to which the temperature information is output may be any part of the rotor and is not limited to the permanent magnet 25. For example, the above-described temperature characteristic data determination method and temperature characteristic data determination device 1 may be applied to a temperature information output device that outputs temperature information related to the temperature of the shaft 21, or may be applied to a temperature information output device that outputs temperature information related to the temperature of the steel plates that make up the rotor core 23.

[0136] In the above-described embodiment and modified examples, the temperature information output device to which the temperature characteristic data determining method and the temperature characteristic data determining device 1 are applied is a magnet temperature information output device OD provided for a rotating electric machine including a stator and a rotor in which a permanent magnet 25 is arranged. However, the temperature information output device to which the above-described temperature characteristic data determining method and the temperature characteristic data determining device 1 are applied may be any temperature information output device provided for a rotating electric machine including a stator and a rotor. In other words, in the above-described rotating electric machine, the permanent magnet 25 does not have to be arranged in the rotor. A rotating electric machine in which the permanent magnet 25 is not arranged in the rotor includes, for example, a wound-field motor. [Explanation of symbols]

[0137] 1...temperature characteristic data determination device, 10...stator, 20...rotor, 25...permanent magnet, 50...element unit, 51...thermosensitive element, 53...coil, 60...element unit, 61...coil, 70...electrical resistance element, 80...output section, OD...magnet temperature information output device.

Claims

1. 1. A temperature characteristic data determination method applied to 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, comprising: The temperature information output device is a first element unit provided on the rotor, the first element unit having 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; an electric resistance element electrically connected to the second element unit; an output unit electrically connected to the second element unit and the electric resistance element, and configured to output an electric signal corresponding to the magnitude of a voltage drop occurring in the electric resistance element as the temperature information, determining an application frequency indicating a frequency of an AC voltage to be applied to the second coil so as to correspond to a facing distance between the first coil and the second coil; and determining, for each of a plurality of frequencies, the temperature characteristic data corresponding to the applied frequency as target temperature characteristic data to be used when obtaining the temperature of the part using the temperature information, by referring to a database that stores, for each of a plurality of frequencies, temperature characteristic data that indicates the relationship between the frequency, a value based on an electrical signal corresponding to the magnitude of voltage drop, and temperature, in association with each other.

2. 2. The temperature characteristic data determination method according to claim 1, wherein determining the applied frequency includes determining, as the applied frequency, the frequency of an AC voltage whose phase difference with the electrical signal output from the output section is within a predetermined range when the temperature of the temperature-sensing element is at room temperature.

3. The temperature characteristic data determination method of claim 1, wherein determining the applied frequency includes determining, as the applied frequency, a frequency at which a value based on the electrical signal output from the output section becomes an extreme value when the temperature of the temperature-sensing element is at room temperature.

4. 1. A temperature characteristic data determination method applied to 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, comprising: The temperature information output device is a first element unit provided on the rotor, the first element unit having 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; an electric resistance element electrically connected to the second element unit; an output unit electrically connected to the second element unit and the electric resistance element, and configured to output an electric signal corresponding to the magnitude of a voltage drop occurring in the electric resistance element as the temperature information, applying an AC voltage having a frequency lower than a predetermined resonant frequency to the second coil when the temperature sensing element is at a predetermined temperature, the AC voltage exciting the first coil; acquiring the electrical signal output from the output unit by the application; and determining, as target temperature characteristic data to be used when obtaining the temperature of the part using the temperature information, the temperature characteristic data in which the value based on the electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature corresponds to the value based on the acquired electrical signal, by referring to a database that stores multiple pieces of temperature characteristic data, each of which indicates the relationship between a value based on an electrical signal corresponding to the magnitude of the voltage drop at the predetermined temperature and a temperature.

5. 1. A temperature characteristic data determination device applied to 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, The temperature information output device is a first element unit provided on the rotor, the first element unit having 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; an electric resistance element electrically connected to the second element unit; an output unit electrically connected to the second element unit and the electric resistance element, and configured to output an electric signal corresponding to the magnitude of a voltage drop occurring in the electric resistance element as the temperature information, The temperature characteristic data determination device includes: determining an application frequency indicating a frequency of an AC voltage to be applied to the second coil so as to correspond to a facing distance between the first coil and the second coil; a temperature characteristic data determination device that refers to a database that stores, for each of a plurality of frequencies, temperature characteristic data that indicates the relationship between the frequency, a value based on an electrical signal corresponding to the magnitude of voltage drop, and temperature, in association with each other, and determines the temperature characteristic data that corresponds to the applied frequency as target temperature characteristic data to be used when obtaining the temperature of the part using the temperature information.

6. 1. A temperature characteristic data determination device applied to 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, The temperature information output device is a first element unit provided on the rotor, the first element unit having 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; an electric resistance element electrically connected to the second element unit; an output unit electrically connected to the second element unit and the electric resistance element, and configured to output an electric signal corresponding to the magnitude of a voltage drop occurring in the electric resistance element as the temperature information, The temperature characteristic data determination device includes: When the temperature sensing element is at a predetermined temperature, an AC voltage having a frequency lower than a predetermined resonant frequency that excites the first coil is applied to the second coil, thereby obtaining the electrical signal output from the output unit; a temperature characteristic data determination device that refers to a database that stores a plurality of temperature characteristic data that indicate the relationship between a value based on an electrical signal corresponding to the magnitude of a voltage drop and temperature, and determines the temperature characteristic data that corresponds to the value based on the acquired electrical signal, where the value based on the electrical signal corresponding to the magnitude of the voltage drop at the specified temperature, as target temperature characteristic data to be used when obtaining the temperature of the part using the temperature information.

7. 1. A temperature characteristic data determination method applied to a temperature information output device that outputs temperature information related to temperatures of portions of a rotor in a rotating electric machine having a stator and a rotor, comprising: The temperature information output device is a first element unit having 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 having a second coil magnetically coupled to the first coil; an electric resistance element electrically connected to the second element unit; an output unit electrically connected to the second element unit and the electric resistance element, and configured to output an electric signal corresponding to the magnitude of a voltage drop occurring in the electric resistance element as the temperature information, obtaining a first composite impedance; adjusting the second composite impedance to a value corresponding to the first composite impedance; generating temperature characteristic data after said adjusting; storing the temperature characteristic data in a database; In the obtaining, the first synthetic impedance is a synthetic impedance of the first coil and the second coil when, in a first state in which the first element unit is attached to the rotor and the second element unit is attached to the stator, an AC voltage is applied to the second coil, the first coil and the second coil are magnetically coupled, and the temperature sensing element is at a predetermined temperature; By adjusting, the second composite impedance is a composite impedance of the first coil and the second coil when, in a second state in which the first element unit and the second element unit are attached to a temperature characteristic data acquisition device, an AC voltage is applied to the second coil, the first coil and the second coil are magnetically coupled, and the temperature sensing element is at a predetermined temperature; the temperature characteristic data acquisition device is used to generate the temperature characteristic data indicating a relationship between a value based on the electrical signal and a temperature, and is a device different from the rotating electric machine, generating the temperature characteristic data includes applying an AC voltage to the second coil in the second state and outputting the electrical signal while changing the temperature of the temperature sensing element, and generating the temperature characteristic data; The temperature characteristic data determination method, wherein the storing step includes storing the frequency of the AC voltage applied to the second coil in the generating step and the generated temperature characteristic data in a database in association with each other.

8. 8. The temperature characteristic data determination method according to claim 7, wherein the adjusting step includes adjusting the second composite impedance to a value within a range of 95% to 105% of the first composite impedance.

9. determining an application frequency indicating a frequency of an AC voltage to be applied to the second coil so as to correspond to a facing distance between the first coil and the second coil in the first state; 9. The temperature characteristic data determination method according to claim 7, further comprising: referring to the database and determining the temperature characteristic data corresponding to the applied frequency as target temperature characteristic data to be used when obtaining the temperature of the part using the temperature information.

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