Temperature detection device, coil, transformer, and temperature detection method

Abstract

A temperature detection device according to one aspect of the present disclosure comprises a twisted wire and a detector. The twisted wire is formed of one conductor. The twisted wire is provided so as to be in contact with the conductive wire of the coil. The detector detects the temperature of the conductive wire on the basis of the resistance value of the twisted wire.

Description

Temperature detection device, coil, transformer, and temperature detection method

[0001] The present invention relates to a temperature detection device, a coil, a transformer, and a temperature detection method.

[0002] Transformers used for power conversion, such as AC / DC conversion and DCDC converters, have conductors wound around their cores. The transformer conductors can heat up because a large current flows through them. Therefore, when using a transformer, it is necessary to monitor the heat generated by the conductors.

[0003] Thermocouples or thermistors are generally used as temperature sensors for monitoring heat generation in conductors (see, for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2001-044052

[0005] It is technically difficult to install a temperature sensor such as a thermocouple or thermistor inside the windings of a transformer. For this reason, when using a temperature sensor such as a thermocouple or thermistor, the temperature sensor is installed near the transformer to monitor the temperature around the transformer. However, this method makes it difficult to accurately detect the temperature of the windings.

[0006] The present disclosure has been made in view of the above, and aims to provide a temperature detection device, a coil, a transformer, and a temperature detection method that can improve the accuracy of temperature detection of windings.

[0007] A temperature detection device according to one aspect of the present disclosure includes a stranded wire and a detector. The stranded wire is formed of a single conductor. The stranded wire is arranged to contact a conductor of a coil. The detector detects the temperature of the conductor based on the resistance value of the stranded wire.

[0008] According to the present disclosure, the accuracy of detecting the temperature of the winding can be improved.

[0009] FIG. 1 is an explanatory diagram showing a temperature detection device according to an embodiment. FIG. 2 is an explanatory diagram showing a twisted wire according to an embodiment. FIG. 3 is an explanatory diagram showing the relationship between current, resistance, and temperature in a resistance method. FIG. 4 is an explanatory diagram showing an example of an arrangement of twisted wire according to an embodiment. FIG. 5 is an explanatory diagram showing an example of an arrangement of twisted wire according to an embodiment. FIG. 6 is an explanatory diagram showing an example of an arrangement of twisted wire according to an embodiment. FIG. 7 is an explanatory diagram showing an example of an arrangement of twisted wire according to an embodiment. FIG. 8 is an explanatory diagram showing an example of an arrangement of twisted wire according to an embodiment. FIG. 9 is an explanatory diagram showing an example of an arrangement of twisted wire according to an embodiment. FIG. 10 is an explanatory diagram showing an example of an arrangement of twisted wire according to an embodiment. FIG. 11 is an explanatory diagram showing an application example of a temperature detection device according to an embodiment. FIG. 12 is an explanatory diagram showing an application example of a temperature detection device according to an embodiment. FIG. 13 is an explanatory diagram showing an application example of a temperature detection device according to an embodiment.

[0010] Hereinafter, with reference to the accompanying drawings, embodiments of a temperature detection device, a coil, a transformer, and a temperature detection method will be described in detail. Note that the present invention is not limited to the embodiments described below. Furthermore, each embodiment can be appropriately combined within a range that does not cause contradictions in the processing content. Furthermore, the same components in each of the following embodiments will be given the same reference numerals, and duplicated explanations will be omitted.

[0011] 1. Configuration of the Temperature Detecting Device Fig. 1 is an explanatory diagram showing a temperature detecting device 2 according to an embodiment. As shown in Fig. 1, the temperature detecting device 2 includes a twisted wire 3 and a detector 4. The twisted wire 3 is formed from a single conductor. As shown in Fig. 2, the twisted wire 3 is formed by bending a single conductor that is thinner than the conductor wire of a coil at the center in the longitudinal direction and twisting the conductor.

[0012] The length of the conductor used in the stranded wire 3 is, for example, 6 m to 10 m. Therefore, the length of the stranded wire 3 is 3 m to 5 m. The cross-sectional area of ​​the conductor used in the stranded wire 3 is smaller than the cross-sectional area of ​​the coil conductor 11. For example, the wire diameter of the conductor is 0.10 mm to 1.5 mm.

[0013] The stranded wires 3 are configured to contact the conductor wires 11 of the coil. For example, the stranded wires 3 are wound around the core 10 of the coil so as to contact the conductor wires 11 wound around the core 10. The core may be made of iron, for example. Alternatively, it may be made of an insulator or air. Examples of the arrangement of the stranded wires 3 will be described later with reference to FIGS. 4 to 10.

[0014] The detector 4 measures the temperature of the conductor 11 in contact with the stranded wire 3 by the resistance method. The resistance method is a method of measuring temperature by utilizing the property that the resistivity of metal changes with temperature. For example, when a current is passed through the coil conductor 11, the relationship between the current value, the resistance value of the stranded wire 3, and the ambient temperature of the conductor is as shown in Figure 3.

[0015] As shown in Figure 3, the resistance of a conductor increases as the ambient temperature of the conductor increases. In other words, the higher the ambient temperature of the conductor, the higher the resistance of the conductor when a constant current is passed through it. Thus, there is a correlation between the ambient temperature of the conductor and the resistance of the conductor when a constant current is passed through it.

[0016] In the resistance method, the temperature before current application [℃] = t １ , resistance before current application [Ω] = R １ , temperature after energization [°C] = t2, and resistance after energization [Ω] = R ２ The relationship of the following formula (1) holds: The value [234.5] in the formula is a value specific to copper, and varies depending on the material. From the above formula (1), the temperature [°C] after energization = t2 can be derived using the following formula (2).

[0017] Therefore, the detector 4 passes a constant current with a known current value I through the conductor of the twisted wire 3, measures the voltage value V between both ends of the conductor, and derives the resistance value R of the conductor at that time, R = V / I, from the voltage value V and the current value I.

[0018] Then, the detector 4 measures the temperature before power is applied [°C] = t １ , resistance before current application [Ω] = R １ , and resistance after current application [Ω] = R ２By substituting this into the above formula (2), the temperature after energization [°C] = t2 is calculated and output. At this time, the twisted wire 3 is in direct contact with the conductor 11 of the coil. This allows the detector 4 to improve the accuracy of temperature detection of the conductor 11, which is the winding wound around the core 10.

[0019] Furthermore, if a single conductor, instead of the twisted wire 3, is wound around the coil core 10 in a single layer and a constant current is passed through it, a voltage will be generated by electromagnetic induction in response to changes in the magnetic flux of the core 10, reducing the accuracy of temperature detection. However, in this embodiment, the conductor is a double wire, forming the twisted wire 3.

[0020] The use of such a twisted wire 3 minimizes the area of ​​the surface surrounded by the double conductor and minimizes the external magnetic flux penetrating this surface, thereby canceling electromagnetic induction caused by changes in the magnetic flux of the core 10. As a result, when the resistance value of the twisted wire 3 is calculated from the potential difference between both ends of the conductor of the twisted wire 3 when a constant current is passed through the twisted wire 3, and the temperature of the conductor 11 is calculated from this resistance value by the resistance method, the accuracy of calculating the temperature of the conductor 11 can be improved.

[0021] [2. Examples of Stranded Wire Arrangement] Next, examples of the arrangement of the stranded wire 3 according to the embodiment will be described with reference to Fig. 4 to Fig. 10. Fig. 4 to Fig. 10 are explanatory diagrams showing examples of the arrangement of the stranded wire 3 according to the embodiment. Note that the detector 4 is not shown in Fig. 6 to Fig. 10.

[0022] 1, the twisted wire 3 is wound multiple times around the core 10 of the coil, but as shown in Fig. 4, the twisted wire 3 may be arranged so as to make one turn around the core 10. This allows the temperature detection device 2 to have a shorter length of the conductor constituting the twisted wire 3 than in the example shown in Fig. 1, thereby enabling cost reduction.

[0023] Furthermore, the stranded wire 3 does not necessarily have to be arranged so as to wrap around the core 10. For example, as shown in Fig. 5, the stranded wire 3 may be arranged so as to wrap around half of the surface of the side circumferential surface of the core 10. This allows the temperature detection device 2 to have a shorter length of the conductor constituting the stranded wire 3 than the example shown in Fig. 4, thereby enabling further cost reduction.

[0024] 5 and 6, the stranded wire 3 is preferably arranged in the central portion in the axial direction of the core 10. When the stranded wire 3 is arranged at the end portion in the axial direction of the core 10, the temperature detection accuracy of the temperature detection device 2 may be reduced due to differences in outside air temperature, but when the stranded wire 3 is arranged in the central portion in the axial direction of the core 10, the influence of changes in outside air temperature is reduced, thereby improving the accuracy of temperature detection.

[0025] 6, the stranded wire 3 may be wound around the core 10 in parallel with the coil conductor 11. This allows the temperature detection device 2 to measure the temperature of the entire coil conductor 11.

[0026] 7, the stranded wire 3 may be wound around the core 10 along a spiral recess formed between adjacent conductive wires 11 wound around the core 10. This allows the temperature detection device 2 to be arranged in a coil in which the conductive wires 11 are wound around the core 10 without any gaps.

[0027] Furthermore, since the twisted wire 3 is disposed in the spiral recess formed between adjacent conductors 11, the diameter of the wound wire is smaller than when the twisted wire 3 is disposed in a portion other than the recess of the conductor 11. Therefore, the temperature detection device 2 can be miniaturized when disposed in a coil.

[0028] 8, the twisted wire 3 may be wound on the conductor 11 wound around the core 10. This allows the temperature detection device 2 to be retrofitted to an existing coil. As shown in FIG. 9, the twisted wire 3 may be wound around the core 10 before the conductor 11 is wound thereon. In this case, the conductor 11 is wound on the twisted wire 3. This makes the twisted wire 3 less susceptible to changes in the outside air temperature, improving the accuracy of temperature detection of the conductor 11.

[0029] 10 , the stranded wire 3 may be wound around the conductor 11 and then wound around the core 10 together with the conductor 11. This allows the temperature detection device 2 to detect a temperature that reflects the temperature of the entire surface of the conductor 11, thereby improving the accuracy of temperature detection of the conductor 11.

[0030] Furthermore, the temperature detection device 2 according to the embodiment may be configured so that the detector 4 is detachable from the stranded wire 3. In other words, the coil according to the embodiment may be configured to include the conductor 11 wound around the core 10 and the stranded wire 3 formed of a single conductor that is provided so as to be in contact with the conductor 11.

[0031] In this case, the stranded wire 3 is connected to a detector 4 that detects the temperature of the conductor 11 based on the resistance value of the stranded wire 3. The stranded wire 3 may be arranged in any of the arrangements shown in Figures 1 and 4 to 10.

[0032] 3. Application Examples of the Temperature Detection Device According to the Embodiment Next, application examples of the temperature detection device according to the embodiment will be described with reference to Fig. 11 to Fig. 13. Fig. 11 to Fig. 13 are explanatory diagrams showing application examples of the temperature detection device according to the embodiment. The temperature detection device according to the embodiment can be applied to any device that includes windings of a conducting wire 11 that is energized, such as a transformer, a toroidal coil, and a motor armature.

[0033] The transformer shown in Fig. 11 is built into, for example, an on-board charger for a vehicle. As shown in Fig. 11, a transformer 31 to which the temperature detection device according to the embodiment is applied includes a rectangular annular core 12, a primary coil conductor 11A, a secondary coil conductor 11B, twisted wires 3A and 3B, and detectors 4A and 4B. The primary coil conductor 11A and the secondary coil conductor 11B are conductors.

[0034] The primary coil conductor 11A is wound around the core 12 so as to surround one side and the inner side of the periphery of the core 12. The primary coil conductor 11A is connected to a primary circuit 13. The secondary coil conductor 11B is wound around the core 12 so as to surround the other side of the periphery of the core 12 that faces the one side and the inner side. The secondary coil conductor 11B is connected to a secondary circuit 14.

[0035] The twisted wires 3A and 3B are each formed of a single conductor. The twisted wire 3A is arranged so as to contact the conductor wire 11A of the primary coil. The twisted wire 3B is arranged so as to contact the conductor wire 11B of the secondary coil. The twisted wires 3A and 3B may be arranged in any of the arrangements shown in Figures 1 and 4 to 10.

[0036] Detector 4A is provided in primary circuit 13 and connected to stranded wire 3A. Detector 4B is provided in secondary circuit 14 and connected to stranded wire 3B. Detectors 4A and 4B are the same as detector 4 shown in FIG. 1. That is, detector 4A detects the temperature of primary coil conductor 11A based on the resistance value of stranded wire 3A. Detector 4B detects the temperature of secondary coil conductor 11B based on the resistance value of stranded wire 3B.

[0037] As a result, the temperature detecting device 2A including the twisted wire 3A and the detector 4A can improve the accuracy of temperature detection of the primary coil conductor 11A. The temperature detecting device 2B including the twisted wire 3B and the detector 4B can improve the accuracy of temperature detection of the secondary coil conductor 11B. The transformer 31 may be configured to include at least one of the temperature detecting devices 2A and 2B.

[0038] 12, a toroidal coil 32 to which the temperature detection device according to the embodiment is applied includes a ring-shaped core 15, a conductor 11, a twisted wire 3, and a detector 4. The conductor 11 is wound around the core 15 so as to surround the outer and inner peripheries of the core 15. The twisted wire 3 is arranged so as to be in contact with the conductor 11. The twisted wire 3 may be arranged in any of the arrangements shown in FIGS. 1 and 4 to 10.

[0039] The stranded wire 3 is connected to a detector 4. The detector 4 is the same as the detector 4 shown in FIG. 1 . That is, the detector 4 detects the temperature of the conductor 11 based on the resistance value of the stranded wire 3. This allows the temperature detection device 2C employed in the toroidal coil 32 to improve the accuracy of temperature detection of the conductor 11 of the toroidal coil 32.

[0040] 13, a motor armature 33 to which the temperature detection device according to the embodiment is applied includes a plurality of teeth 16, conductors 11, stranded wires 3, and a detector 4. The teeth 16 are provided so as to protrude from the outer periphery of a hollow cylindrical stator.

[0041] The conductor wire 11 is wound around each tooth 16. The stranded wire 3 is arranged so as to come into contact with at least one of the conductor wires wound around each of the plurality of teeth 16. The arrangement of the stranded wire 3 may be any of the arrangements shown in Fig. 1 and Figs. 4 to 10.

[0042] 1. That is, the detector 4 detects the temperature of the conductor 11 based on the resistance value of the stranded wire 3. This allows the temperature detection device 2D employed in the motor armature 33 to improve the accuracy of temperature detection of the conductor 11 of the motor armature 33.

[0043] [4. Supplementary Note] The present technology may have the following configurations. (1) A temperature detection device comprising: a twisted wire formed of a single conductor arranged to contact a conductor of a coil; and a detector that detects the temperature of the conductor based on the resistance value of the twisted wire. (2) The temperature detection device described in (1), in which the twisted wire is wound around a core in parallel with the conductor. (3) The temperature detection device described in (1), in which the twisted wire is wound on top of the conductor wound around the core. (4) The temperature detection device described in (1), in which the twisted wire is wound around a core before the conductor is wound around it. (5) The temperature detection device described in (1), in which the twisted wire is wound around the core along a spiral recess formed between adjacent conductors wound around the core. (6) The temperature detection device described in (1), in which the twisted wire is wound around the conductor and then wound around the core together with the conductor. (7) A coil comprising: a conductor wound around a core; and a twisted wire formed by a single conductor arranged to contact the conductor, wherein the twisted wire is connected to a detector that detects the temperature of the conductor based on the resistance value of the twisted wire. (8) A transformer comprising: a primary winding wound around an annular core; a secondary winding wound around the core; a twisted wire formed by at least one conductor arranged to contact the conductor of the primary winding or the secondary winding; and a detector that detects the temperature of the conductor based on the resistance value of the twisted wire. (9) A temperature detection method in which the temperature of the conductor is detected by a detector based on the resistance value of the twisted wire formed by a single conductor arranged to contact the conductor of a coil.

[0044] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims

1. A temperature detection device comprising: a stranded wire formed by a single conductor that is arranged to contact the conductor of a coil; and a detector that detects the temperature of the conductor based on the resistance value of the stranded wire.

2. The temperature detection device according to claim 1, wherein the stranded wire is wound around a core in parallel with the conductor.

3. The temperature detection device according to claim 1, wherein the stranded wire is wound on the conductor wound around a core.

4. The temperature detection device according to claim 1, wherein the stranded wire is wound around a core before the conductor is wound around the core.

5. The temperature detection device according to claim 1, wherein the stranded wire is wound around the core along a spiral recess formed between adjacent conductive wires wound around the core.

6. The temperature detection device according to claim 1, wherein the stranded wire is wound around the conductor and wound around a core together with the conductor.

7. A coil comprising: a conducting wire wound around a core; and a stranded wire formed by a single conductor arranged to be in contact with the conducting wire, the stranded wire being connected to a detector that detects the temperature of the conducting wire based on the resistance value of the stranded wire.

8. A transformer comprising: a primary winding wound around an annular core; a secondary winding wound around said core; a stranded wire formed by at least one conductor arranged so as to be in contact with the conductor of said primary winding or said secondary winding; and a detector for detecting the temperature of said conductor based on the resistance value of said stranded wire.

9. A temperature detection method in which the temperature of a conductor is detected by a detector based on the resistance value of a stranded wire formed by a single conductor that is provided so as to contact the conductor of a coil.

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