Detection device

Abstract

To provide a detection device capable of accurately detecting the rotation speed of an inductive motor even when the inductive motor is used in an application that turns an internal environment into an extreme environment.SOLUTION: A detection device is provided, comprising a first detection unit for detecting the intensity of a magnetic field leaking out of an inductive motor on the outside of the inductive motor, and an output unit configured to output rotation speed information including information indicating the rotation speed of the inductive motor based on a first signal output from the first detection unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a detection device. [Background technology]

[0002] Research and development is being conducted on a detection device for detecting the rotation speed of an induction motor.

[0003] In relation to this, a method (resolver method) is known in which a specific carrier frequency is applied and time-dependent changes in the magnetic field caused by the rotation of the rotor are detected by multiple coils with different detection phases, thereby determining the mechanical angle and rotation speed of the rotor (see Patent Document 1).In addition, a method (hall sensor method) is known in which a permanent magnet is carried on the rotor and the magnetic flux of the permanent magnet of the rotor is detected by a magnetic sensor, thereby determining the rotation speed of the rotor (see Non-Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-056676 A [Non-patent literature]

[0005] [Non-Patent Document 1] Renesas Electronics Corporation, "Motor Solutions Catalog", [online], [searched June 15, 2020], Internet<URL: https: / / www.renesas.com / jp / ja / document / bro / motor-solution-brochure> Summary of the Invention [Problem to be solved by the invention]

[0006] Here, in the method described in Patent Document 1, in order to detect the rotation speed of the induction motor, a resolver must be provided inside the induction motor. Also, in the method described in Patent Document 2, in order to detect the rotation speed of the induction motor, a hall sensor must be provided inside the induction motor. Thus, in the past, in order to detect the rotation speed of the induction motor, it was necessary to provide a member for detecting the rotation speed of the induction motor (for example, the above-mentioned resolver, hall sensor, etc.) inside the induction motor. On the other hand, when the induction motor is used for a specific purpose such as driving a pump that injects rocket fuel, the members provided inside the induction motor may be exposed to extreme environments such as high temperature, high pressure, and high vibration. However, the members provided inside the induction motor often cannot withstand extreme environments. For this reason, the emergence of a device adopting a new method as a device for detecting the rotation speed of the induction motor was desired.

[0007] The present disclosure has been made in consideration of the above circumstances, and has an objective of providing a detection device that can accurately detect the rotation speed of an induction motor even when the induction motor is used in an application where the internal environment is extreme. [Means for solving the problem]

[0008] One aspect of the present disclosure is a detection device that includes a first detection unit that detects the intensity of a leakage magnetic field leaking from an induction motor outside the induction motor, and an output unit that outputs rotation speed information including information indicating the rotation speed of the induction motor based on a first signal output from the first detection unit. Effect of the Invention

[0009] According to the present disclosure, even if an induction motor is used in an application where the internal environment is an extreme environment, the rotation speed of the induction motor can be detected with high accuracy. [Brief description of the drawings]

[0010] [Figure 1]1 is a diagram showing an example of the configuration of a detection device 1. FIG. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a main unit 20. [Diagram 3] 1 is a diagram showing an example of a flow of processing performed by the detection device 1 every time a predetermined update period elapses. [Figure 4] FIG. 11 is a diagram showing an example of a frequency spectrum indicated by the information generated in step S130. [Diagram 5] 1 is a diagram showing an example of a flow of processes performed by a control device 2 every time rotation speed information is obtained from a detection device 1. FIG. [Figure 6] FIG. 6 is an image diagram showing the flow of processes performed by the detection device 1 and the control device 2 described with reference to FIGS. 3 and 5. [Figure 7] 3 is a diagram showing another example of the configuration of the detection device 1. FIG. [Figure 8] 13 is a diagram showing yet another example of the configuration of the detection device 1. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Embodiment> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0012] <Detection device overview> First, an overview of the detection device according to this embodiment will be described.

[0013] The detection device according to the embodiment includes a first detection unit and an output unit. The first detection unit detects the strength of a leakage magnetic field leaking from the induction motor outside the induction motor. The output unit outputs rotation speed information including information indicating the rotation speed of the induction motor based on a first signal output from the first detection unit.

[0014] As a result, the detection device according to the embodiment can detect the rotation speed of an induction motor with high accuracy even when the induction motor is used in an application in which the internal environment is an extreme environment.

[0015] The configuration of the detection device according to the embodiment and the processing performed by the detection device will be described in detail below.

[0016] <Detection device configuration> The configuration of the detection device according to the embodiment will be described below by taking the detection device 1 as an example.

[0017] FIG. 1 is a diagram showing an example of the configuration of a detection device 1. As shown in FIG.

[0018] The detector 1 detects the rotation speed of an induction motor. In the example shown in FIG. 1, the detector 1 detects the rotation speed of the induction motor M. The induction motor M is a three-phase induction motor of a winding type. The induction motor M may be another induction motor such as a three-phase induction motor of a squirrel cage type instead of a three-phase induction motor of a winding type. In FIG. 1, in order to clarify the internal structure of the induction motor M, the induction motor M is drawn so that a cross section of the induction motor M cut by a virtual plane perpendicular to the rotation axis of the induction motor M can be seen. The internal structure of the induction motor M is known, and may be any structure that can be driven as an induction motor, so that a detailed description using symbols will be omitted.

[0019] The induction motor M generates a rotating magnetic field in the stator and rotates the rotor by the generated rotating magnetic field. Since the induction motor M is a wound-type three-phase induction motor, coils are wound around the stator and rotor of the induction motor M in a predetermined manner. Each of the multiple coils wound around the stator becomes a field magnet when a current flows through it. The induction motor M rotates the rotor by passing an induced current through the rotor coils using the magnetic fields from the field magnets. Most of the magnetic field generated in this way within the housing of the induction motor M does not leak out of the housing of the induction motor M. However, a part of the magnetic field leaks out of the housing of the induction motor M. In the following, for convenience of explanation, the magnetic field leaking out of the housing of the induction motor M in this way will be referred to as a leakage magnetic field.

[0020] The detection device 1 detects a leakage magnetic field outside the housing of the induction motor M, and detects the rotation speed of the induction motor M based on the detected leakage magnetic field. Therefore, even if the induction motor M is used for an application in which the environment inside the housing of the induction motor M is an extreme environment, the detection device 1 is not directly exposed to the extreme environment. As a result, the detection device 1 can suppress the occurrence of malfunctions and can accurately detect the rotation speed of the induction motor.

[0021] The extreme environment is, for example, an environment in which at least one of high temperature, high pressure, and high vibration is realized, such as the environment inside an induction motor that drives an electric turbo pump of a rocket. In such an extreme environment, in the housing of the induction motor that includes a component for detecting the rotation speed, such as a resolver or a Hall sensor, the component may not be able to withstand the extreme environment and may cause a malfunction. This is undesirable because it may lead to failure of the rocket launch. For this reason, the detection device 1 that detects the leakage magnetic field outside the housing of the induction motor M is useful because it can accurately detect the rotation speed of the induction motor M even if the induction motor M is used for an application in which the environment inside the housing of the induction motor M is an extreme environment.

[0022] Furthermore, since the detection device 1 detects a leakage magnetic field outside the housing of the induction motor M, it is not necessary to embed the detection device 1 inside the housing of the induction motor M during the manufacturing stage of the induction motor M. In other words, the detection device 1 can be attached from the outside to the induction motor M after it has been manufactured, thereby improving the degree of freedom in designing various devices including the detection device 1.

[0023] The detection device 1 includes, for example, a detection unit 10 and a main unit 20. The detection device 1 may further include other devices, other members, etc. In the example shown in FIG. 1, the main unit 20 is communicably connected to a control device 2 that controls an induction motor M. In this example, the detection unit 10 is configured separately from the main unit 20. However, the detection unit 10 may be configured integrally with the main unit 20.

[0024] The detection unit 10 detects the strength of the leakage magnetic field leaking from the induction motor M outside the housing of the induction motor M (i.e., outside the induction motor M). The detection unit 10 is, for example, a magnetic impedance sensor. The detection unit 10 may be a Hall sensor or the like instead of a magnetic impedance sensor. However, since the detection unit 10 is capable of detecting the strength of the leakage magnetic field even when the strength of the leakage magnetic field from the induction motor M is small, it is desirable for the detection unit 10 to be a sensor that can detect the leakage magnetic field with higher sensitivity than a Hall sensor, such as a magnetic impedance sensor. The following describes, as an example, a case where the detection unit 10 is a magnetic impedance sensor.

[0025] The detection unit 10 detects the strength of the leakage magnetic field and outputs a signal indicating the detected strength to the main device 20. This signal may be an analog signal or a digital signal. In the following, as an example, a case where the signal output from the detection unit 10 is an analog signal will be described.

[0026] Here, the detection unit 10 may be provided on the outer surface of the induction motor M, or may be provided apart from the outer surface of the induction motor. However, the detection unit 10 is provided at a position outside the housing of the induction motor M where it does not interfere with other members and where it can detect the change in the strength of the leakage magnetic field over time. Therefore, even if the detection unit 10 is at a position outside the housing of the induction motor M where it can detect the strength of the leakage magnetic field, it is not provided at a position where the strength of the leakage magnetic field does not change over time. A position outside the housing of the induction motor M where it does not interfere with other members and where it can detect the change in the strength of the leakage magnetic field over time is identified, for example, by a prior experiment, a simulation, or the like. Note that the position may be identified by another method.

[0027] The main device 20 calculates the rotation speed of the induction motor M based on the signal output from the detection unit 10. The main device 20 outputs rotation speed information including information indicating the calculated rotation speed. For example, the main device 20 outputs the calculated rotation speed information to the control device 2. This allows the detection device 1 to cause another device, such as the control device 2, to control the induction motor M in accordance with the rotation speed of the induction motor M. Note that the rotation speed information is not the signal itself output from the detection unit 10.

[0028] Here, the rotation speed information includes at least one of target value information indicating a target value of the rotation speed of the induction motor M and difference information indicating the difference between the rotation speed of the induction motor M and the target value. In the following, as an example, a case will be described in which the rotation speed information includes difference information together with information indicating the rotation speed of the induction motor M. In this case, the main unit device 20 calculates the target value together with the rotation speed of the induction motor M. Then, the main unit device 20 calculates the difference between the rotation speed and the target value. This allows the main unit device 20 to generate difference information.

[0029] When the control device 2 acquires the rotation speed information output from the main body device 20, the control device 2 controls the induction motor M based on the rotation speed indicated by the information included in the acquired rotation speed information and the difference indicated by the difference information included in the rotation speed information. Specifically, in this case, the control device 2 changes the rotation speed of the induction motor M so that the rotation speed of the induction motor M approaches a target value of the rotation speed of the induction motor M.

[0030] <Main unit configuration> The configuration of the main unit 20 will be described below with reference to Fig. 2. Fig. 2 is a diagram showing an example of the configuration of the main unit 20.

[0031] The main body device 20 includes, for example, a control unit 21, a storage unit 22, and a communication unit 23. Note that the main body device 20 may include other functional units in addition to the control unit 21, the storage unit 22, and the communication unit 23.

[0032] The control unit 21 controls the entire detection device 1. The control unit 21 includes a processor such as a CPU (Central Processing Unit) and an FPGA (Field Programmable Gate Array).

[0033] The control unit 21 includes, for example, an acquisition unit 211, an AD (Analog Digital) conversion unit 212, a Fourier transform unit 213, a calculation unit 214, and an output unit 215. These functional units included in the control unit 21 are, for example, hardware functional units such as an LSI (Large Scale Integration) and an ASIC (Application Specific Circuit). Note that some or all of these functional units included in the control unit 21 may be realized by a processor included in the control unit 21 executing various programs stored in the storage unit 22.

[0034] The acquisition unit 211 acquires the signal output from the detection unit 10 for a predetermined time every time a predetermined update period has elapsed. The predetermined update period varies depending on the content of the control performed in response to the rotation speed information output from the detection device 1. For example, the predetermined update period is 1 second, but is not limited to this. The predetermined time also varies depending on the target value of the rotation speed of the induction motor M. For example, when the target value is 60000 [rpm], the target value is about several milliseconds, but is not limited to this. The predetermined time may be any time as long as it is a time that allows acquisition of a signal that can detect the rotation speed of the induction motor M.

[0035] The AD conversion unit 212 may be any circuit that converts the signal acquired by the acquisition unit 211 into a digital signal, and is, for example, an AD converter.

[0036] The Fourier transform unit 213 performs a Fourier transform on the digital signal converted by the AD conversion unit 212, and generates information indicating the frequency spectrum of the digital signal. The Fourier transform unit 213 generates the information by, for example, executing an FFT (Fast Fourier Transform) on the digital signal.

[0037] The calculation unit 214 specifies the rotation speed of the induction motor M and a target value of the rotation speed of the induction motor M, based on the frequency spectrum indicated by the information generated by the Fourier transform unit 213. Furthermore, the calculation unit 214 calculates the difference between the rotation speed and the target value.

[0038] The output unit 215 generates rotation speed information including information indicating the rotation speed of the induction motor M calculated by the calculation unit 214 and difference information indicating the difference calculated by the calculation unit 214. The output unit 215 outputs the generated rotation speed information. For example, the output unit 215 outputs the rotation speed information to the control device 2. Note that the output unit 215 may be configured to output the rotation speed information to another functional unit included in the main body device 20, may be configured to output the rotation speed information to another device other than the control device 2, or may be configured to output the rotation speed information to another output destination.

[0039] The storage unit 22 is a storage device, such as a random access memory (RAM), a read only memory (ROM), a solid state drive (SSD), etc. The storage unit 22 may be an external storage device connected from the outside.

[0040] The communication unit 23 is a communication device including an antenna for wireless communication, various ports for wired communication, and the like.

[0041] <Processing performed by the detection device> The process performed by the detection device 1 will be described below with reference to FIG. 3. The detection device 1 detects the rotation speed of the induction motor M at a predetermined update period. FIG. 3 is a diagram showing an example of the flow of the process performed by the detection device 1 every time a predetermined update period elapses. In the following, as an example, a case where the induction motor M starts rotating at a timing before the process of step S110 shown in FIG. 3 is performed will be described. In addition, in the following, as an example, a case where a predetermined update period has elapsed at that timing will be described. The detection device 1 repeats the processes of steps S110 to S160 shown in FIG. 3 every time a predetermined update period elapses, for example, until the power supply of the detection device 1 is switched OFF.

[0042] After a predetermined update period has elapsed, the acquisition unit 211 acquires the signal output from the detection unit 10 for a predetermined period of time (step S110).

[0043] Next, the AD conversion unit 212 converts the signal acquired by the acquisition unit 211 in step S110 into a digital signal (step S120).

[0044] Next, the Fourier transform unit 213 performs FFT on the digital signal converted in step S120, and generates information indicating a frequency spectrum (step S130). In Fig. 3, the process of step S130 is indicated by "Fourier transform".

[0045] Next, the calculation unit 214 calculates the rotation speed of the induction motor M and the difference described above based on the frequency spectrum indicated by the information generated in step S130 (step S140). In FIG. 3, the process of step S140 is indicated by "rotation speed calculation". Here, FIG. 4 is a diagram showing an example of a frequency spectrum indicated by the information generated in step S130. The horizontal axis of the graph shown in FIG. 4 indicates frequency. The vertical axis of the graph indicates the strength of the leakage magnetic field. An example of a frequency spectrum indicated by the information generated in step S130 is plotted on the graph. The calculation unit 214 specifies a frequency P1 at the largest peak in the frequency spectrum as shown in FIG. 4 as a target value of the rotation speed of the induction motor M. In the example shown in FIG. 4, the frequency is 52 [Hz]. In this case, the calculation unit 214 specifies about 52 rotations per second, that is, 3120 [rpm] as the target value. On the other hand, the calculation unit 214 specifies the frequency at peak P2 located on the lowest frequency side in the frequency spectrum as shown in FIG. 4 as the rotation speed of the induction motor M. In this example, the frequency is 28 [Hz]. In this case, the calculation unit 214 specifies 28 rotations per second, that is, 1680 [rpm] as the rotation speed. The calculation unit 214 also calculates the difference between the rotation speed of the induction motor M calculated in this way and its target value. In the example shown in FIG. 4, the calculation unit 214 calculates 1440 [rpm] as the difference.

[0046] Next, the output unit 215 generates rotation speed information including information indicating the rotation speed calculated in step S140 and difference information indicating the difference calculated in step S140. Then, the output unit 215 outputs the generated rotation speed information to the control device 2 (step S150).

[0047] After the process of step S150 is performed, the control unit 21 ends the process of the flowchart shown in FIG. 3, and after the next predetermined update period has elapsed, starts the process of the flowchart again.

[0048] <Processing performed by the control device> Hereinafter, with reference to Fig. 5, a process performed by the control device 2 each time rotation speed information is acquired from the detection device 1 will be described. Fig. 5 is a diagram showing an example of a flow of processes performed by the control device 2 each time rotation speed information is acquired from the detection device 1. For example, the control device 2 repeatedly performs the process of step S210 shown in Fig. 5 each time rotation speed information is acquired from the detection device 1.

[0049] After acquiring the rotation speed information output from the detection device 1, the control device 2 performs a rotation speed change process to change the rotation speed of the induction motor M based on the difference information included in the acquired rotation speed information so that the difference indicated by the difference information approaches 0 (step S210). That is, in step S210, the control device 2 brings the rotation speed indicated by the information included in the rotation speed information closer to a target value of the rotation speed of the induction motor M. For example, in the rotation speed change process, the control device 2 controls an inverter (not shown) provided in the control device 2 to change the rotation speed so that the difference approaches 0.

[0050] After the process of step S210 is performed, the control device 2 ends the process of the flowchart shown in FIG. 5, and after acquiring the next rotation speed information, starts the process of the flowchart again.

[0051] Here, FIG. 6 is an image diagram showing the flow of the process performed by the detection device 1 and the control device 2 described in FIG. 3 and FIG. 5. As shown in FIG. 6, the detection device 1 causes the control device 2 to perform feedback control on the rotation speed of the induction motor M. That is, the detection device 1 detects a signal indicating the strength of the leakage magnetic field of the induction motor M (more specifically, an analog signal indicating a temporal change in the strength) by the detection unit 10, and converts the detected signal into a digital signal by the AD conversion unit 212. Then, the detection device 1 converts the converted digital signal into a frequency spectrum by the Fourier transformation unit 213, and calculates the rotation speed of the induction motor M and its target value by the calculation unit 214 based on the converted frequency spectrum. In addition, the detection device 1 calculates the difference between the rotation speed and the target value. As a result, the detection device 1 generates rotation speed information and outputs the generated rotation speed information to the control device 2. The control device 2 controls the inverter provided in the control device 2 based on the acquired rotation speed information, and makes the rotation speed approach the target value (i.e., makes the difference approach 0). The rotation speed of the induction motor M is controlled by such feedback control. The detection device 1 and the control device 2 realize such feedback control based on a signal output from a detection unit 10 located outside the housing of the induction motor M. Therefore, the detection device 1 can realize feedback control of the rotation speed of the induction motor with high accuracy even if the induction motor is used for an application in which the internal environment is an extreme environment.

[0052] The detection device 1 described above may include a cover 40 that covers at least a part of the detection unit 10, as shown in FIG. 7, since the detection unit 10 is located outside the housing of the induction motor M, for example. FIG. 7 is a diagram showing another example of the configuration of the detection device 1. In the example shown in FIG. 7, the detection unit 10 is provided on the outer surface of the housing of the induction motor M. Therefore, the cover 40 covers all of the surfaces of the detection unit 10 that are not in contact with the outer surface, except for a hole through which a cable that connects the detection unit 10 and the main device 20 passes.

[0053] The cover 40 suppresses at least one of the conduction of heat from the outside to the detection unit 10, the conduction of pressure from the outside to the detection unit 10, and the conduction of vibration from the outside to the detection unit 10. The cover 40 may have any configuration as long as it is capable of suppressing at least one of the conductions. This allows the detection unit 10 to accurately detect the strength of the leakage magnetic field even if the induction motor M is, for example, an induction motor mounted on a rocket. In other words, the detection device 1 can accurately detect the rotation speed of the induction motor M even if the induction motor M is used for an application in which the internal environment is an extreme environment.

[0054] When the cover 40 is made of a material that allows the magnetic flux of the leakage magnetic field to pass through, the cover 40 may be configured to cover all surfaces of the detection unit 10 except for a hole through which a cable connecting the detection unit 10 and the main device 20 passes. In this case, the cover 40 can also suppress the transmission of at least one of heat, pressure, and vibration from the induction motor M to the detection unit 10. As a result, the detection device 1 can more reliably and accurately detect the rotation speed of the induction motor M even if the induction motor M is used in an application in which the internal environment is an extreme environment.

[0055] As described above, the detection device 1 according to the embodiment includes the detection unit 10 that detects the strength of the leakage magnetic field leaking from the induction motor M outside the induction motor M, and the output unit 215 that outputs rotation speed information including information indicating the rotation speed of the induction motor M based on a signal output from the detection unit 10. As a result, the detection device 1 can accurately detect the rotation speed of the induction motor M even if the induction motor M is used for an application in which the internal environment is an extreme environment.

[0056] The detection device 1 described above may be configured to include two or more detection units that detect the intensity of the leakage magnetic field, as shown in Fig. 8, for example. Fig. 8 is a diagram showing yet another example of the configuration of the detection device 1. In the example shown in Fig. 8, the detection device 1 includes two detection units, detection unit 10 and detection unit 50, as an example of two or more detection units that detect the intensity of the leakage magnetic field.

[0057] The detection unit 50 detects the strength of the leakage magnetic field leaking from the induction motor M outside the housing of the induction motor M (i.e., outside the induction motor M). The detection unit 50 may be the same type of magnetic sensor as the detection unit 10, or may be a different type of magnetic sensor from the detection unit 10. In the following, as an example, a case where the detection unit 50 is the same type of magnetic sensor as the detection unit 10 will be described. In this case, the detection unit 50 is a magnetic impedance sensor.

[0058] The detection unit 50 detects the intensity of the leakage magnetic field, and outputs a signal indicating the detected intensity to the main device 20. This signal may be an analog signal or a digital signal. In the following, as an example, a case where the signal output from the detection unit 50 is an analog signal will be described.

[0059] Here, the detection unit 50 may be configured to be provided on the outer surface of the induction motor M, or may be configured to be separated from the outer surface of the induction motor. However, like the detection unit 10, the detection unit 50 is provided at a position outside the housing of the induction motor M where it does not interfere with other members and where it can detect the change in the strength of the leakage magnetic field over time. Therefore, even if the detection unit 50 is at a position outside the housing of the induction motor M where it can detect the strength of the leakage magnetic field, it is not provided at a position where the strength of the leakage magnetic field does not change over time. In the example shown in FIG. 8, when the induction motor M is viewed in the direction in which the rotation axis of the induction motor M extends, the detection unit 50 is provided together with the detection unit 10 on a circumference centered on the rotation axis, and is provided at a position where the straight line connecting the rotation axis and the detection unit 50 is inclined by 90° with respect to the straight line connecting the rotation axis and the detection unit 10.

[0060] When the detection device 1 includes the detection unit 50 together with the detection unit 10, the main device 20 calculates the rotation speed of the induction motor M based on the signal output from the detection unit 10 and the signal output from the detection unit 50, and outputs rotation speed information including information indicating the calculated rotation speed. More specifically, the main device 20 generates, for example, a difference between these two signals, and calculates the rotation speed of the induction motor M based on the difference. This allows the detection device 1 to calculate the rotation speed of the induction motor M with higher accuracy. Note that the detection device 1 may be configured to calculate the rotation speed based on other information based on these two signals instead of the difference.

[0061] Furthermore, the items described above may be combined in any manner.

[0062] <Additional Notes> [1] A detection device comprising: a first detection unit that detects the strength of a leakage magnetic field leaking from an induction motor outside the induction motor; and an output unit that outputs rotation speed information including information indicating the rotation speed of the induction motor based on a first signal output from the first detection unit. [2] The detection device according to [1], further comprising a calculation unit that calculates a rotation speed of the induction motor based on the first signal, and the output unit outputs the rotation speed information including information indicating the rotation speed of the induction motor calculated by the calculation unit. [3] The detection device of [1] or [2] further comprises a second detection unit outside the induction motor that detects the intensity of the leakage magnetic field, and the output unit outputs the rotation speed information based on the first signal and a second signal output from the second detection unit. [4] The detection device according to any one of [1] to [3], wherein the first detection unit is provided on an outer surface of the induction motor. [5] The detection device according to any one of [1] to [3], wherein the first detection unit is spaced apart from an outer surface of the induction motor. [6] The detection device described in any one of [1] to [5], wherein the rotation speed information includes at least one of target value information indicating a target value of the rotation speed of the induction motor and difference information indicating a difference between the rotation speed of the induction motor and the target value. [7] The detection device according to any one of [1] to [6], further comprising a cover that covers at least a portion of the detection unit, the cover suppressing at least one of the conduction of heat from the outside to the detection unit, the conduction of pressure from the outside to the detection unit, and the conduction of vibrations from the outside to the detection unit.

[0063] Although an embodiment of the present disclosure has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and may be changed, substituted, deleted, etc. without departing from the gist of the present disclosure. [Explanation of symbols]

[0064] 1 ... detection device, 2 ... control device, 10 ... detection unit, 20 ... main body device, 21 ... control unit, 22 ... storage unit, 23 ... communication unit, 40 ... cover, 50 ... detection unit, 211 ... acquisition unit, 212 ... AD conversion unit, 213 ... Fourier transformation unit, 214 ... calculation unit, 215 ... output unit, M ... induction motor

Claims

1. A first detection unit that detects the intensity of a leakage magnetic field leaking from the induction motor outside the induction motor; an output unit that outputs rotation speed information including information indicating a rotation speed of the induction motor based on a first signal output from the first detection unit; A detection device comprising:

2. A calculation unit that calculates a rotation speed of the induction motor based on the first signal, The output unit outputs the rotation speed information including information indicating the rotation speed of the induction motor calculated by the calculation unit. The detection device according to claim 1 .

3. Further, a second detection unit is provided outside the induction motor, the second detection unit detecting the intensity of the leakage magnetic field, The output unit outputs the rotation speed information based on the first signal and the second signal output from the second detection unit. The detection device according to claim 1 .

4. The first detection unit is provided on an outer surface of the induction motor. The detection device according to claim 1 .

5. The first detection unit is spaced from an outer surface of the induction motor. The detection device according to claim 1 .

6. The rotation speed information includes at least one of target value information indicating a target value of the rotation speed of the induction motor and difference information indicating a difference between the rotation speed of the induction motor and the target value. The detection device according to claim 1 .

7. A cover that covers at least a part of the first detection unit is further provided. the cover suppresses at least one of heat conduction from the outside to the first detection unit, pressure from the outside to the first detection unit, and vibration conduction from the outside to the first detection unit. The detection device according to claim 1 .

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