Rotating electrical machine systems

Abstract

The invention aims to improve the estimation accuracy of the internal distribution state of a rotating electric machine. The rotating electric machine comprises a stator (2), a rotor (3), a shaft (5), a bracket (8, 9) and a sensor (10), wherein the rotor (3) is rotatably arranged on the radial inner side of the stator (2), the shaft (5) is provided as the rotating shaft of the rotor (3), the bracket (8, 9) supports the shaft (5) via bearings (6, 7) so as to be rotatable relative to the stator (2), and the sensor (10) is provided at a portion of the shaft (5) between the rotor (3) and the bearings (6, 7).

Description

Technical Field

[0001] The present invention relates to a rotating electric machine having a sensor on its shaft. Background Art

[0002] Conventionally, there is a rotating electric machine in which an inner hole is provided in the shaft core of a rotor shaft, an abnormal sound detection sensor and a transmitter are provided in the inner hole, and transmission is performed to a transmission antenna arranged on the rotor shaft (for example, Patent Document 1).

[0003] There is also a rotating electric machine that includes a torsion detector and a lead wire in a hollow output shaft. The lead wire is connected to the torsion detector, is formed in a spiral shape, and is led out by passing through a hollow input shaft (for example, Patent Document 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 54-104501

[0007] Patent Document 2: Japanese Utility Model Publication No. 60-096981 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, the above-mentioned rotating electrical machine has a problem that the sensor is provided in the hollow portion of the hollow shaft, which makes it difficult to mount the sensor and reduces the estimation accuracy of the internal distribution state.

[0010] The present invention has been made to solve the above-mentioned problems, and provides a rotating electric machine which has a simple structure and can improve the estimation accuracy of the internal distribution state of the electric motor.

[0011] Solutions to Solve Problems

[0012] The rotating electric machine system disclosed in the present invention includes a rotating electric machine and a control unit that controls the electric power supplied to the rotating electric machine, the rotating electric machine having a stator, a rotor, a shaft, a bracket, and a sensor, the rotor being rotatably arranged radially inward of the stator, the shaft being provided as a rotating shaft of the rotor, the bracket supporting the shaft via a bearing so as to be rotatable relative to the stator, the sensor being provided on the outer diameter side surface of a portion of the shaft between the rotor and the bearing to measure the temperature of the shaft, and the control unit inferring the internal state of the rotating electric machine based on a thermal network model and temperature information of the portion of the shaft between the rotor and the bearing obtained by the sensor.

[0013] Effects of the Invention

[0014] According to the rotating electrical machine disclosed in the present invention, the estimation accuracy of the internal distribution state of the rotating electrical machine can be improved with a simple structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a longitudinal sectional view showing the rotating electrical machine according to the first embodiment of the present disclosure.

[0016] Figure 2 This is a schematic diagram showing a system in which the rotating electrical machine according to the first embodiment of the present disclosure is incorporated.

[0017] Figure 3 This is a schematic diagram of a sensor and a transmission unit according to Embodiment 1 of the present disclosure.

[0018] Figure 4 It is a longitudinal sectional view showing the rotating electrical machine according to the first embodiment of the present disclosure.

[0019] Figure 5 It is a longitudinal sectional view showing a rotating electrical machine according to Embodiment 2 of the present disclosure.

[0020] Figure 6 This is a perspective view in which a part of the shaft of the rotating electrical machine according to Embodiment 3 of the present disclosure is cut away.

[0021] Figure 7 This is a perspective view showing a modified example in which a part of the shaft of the rotating electrical machine according to the third embodiment of the present disclosure is cut away.

[0022] Figure 8 This is a cross-sectional view taken perpendicularly to the axial direction of the shaft of the rotating electrical machine according to the fourth embodiment of the present disclosure.

[0023] Fig. 9 This is a schematic diagram of a rotating electrical machine system according to Embodiment 5 of the present disclosure.

[0024] Fig.10 It is a hardware configuration diagram of a rotating electrical machine system according to Embodiment 5 of the present disclosure.

[0025] Fig.11 It is a diagram showing a control flow chart according to Embodiment 5 of the present disclosure.

[0026] Fig.12 It is a diagram showing a current waveform according to Embodiment 5 of the present disclosure.

[0027] Fig.13 It is a longitudinal sectional view showing a rotating electrical machine according to a sixth embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] Implementation method 1.

[0029] The rotating electrical machine according to Embodiment 1 of the present disclosure will be described.

[0030] Figure 1 1 is a longitudinal sectional view of a rotating electrical machine according to Embodiment 1 of the present disclosure. The direction parallel to the axis of the rotating shaft is set as the rotating shaft direction or axial direction, and the axis of the rotating shaft is set as the central axis. The direction orthogonal to the axis of the rotating shaft is set as the radial direction, the radial outer side is set as the radial outer side or the radial outer side, and the radial inner side is set as the radial inner side or the radial inner side. The direction of rotation around the rotating shaft is set as the circumferential direction or the rotating direction, and the direction opposite to the rotating direction is set as the reverse rotating direction.

[0031] The rotary electric machine 100 of the first embodiment of the present disclosure includes a frame 1, a stator 2, and a rotor 3. The frame 1 is cylindrical, the stator 2 is inserted and held in the frame 1, and the rotor 3 is rotatably disposed radially inside the stator 2 with a gap forming a magnetic gap between the stator 2 and the stator 2. The stator 2 and the rotor 3 are disposed coaxially.

[0032] The stator 2 includes a stator core 21 and a stator coil 4. The stator core 21 is made of a magnetic body such as an electromagnetic steel plate or a powder core. The stator coil 4 is fixed to the stator core 21 via parts such as a bobbin and insulating paper (not shown).

[0033] The rotor 3 has a rotor core 31. The rotor core 31 is made of a magnetic body such as an electromagnetic steel plate or a powder core, similarly to the stator core 21. The rotor core 31 is fastened to the shaft 5 by, for example, press-fitting, shrink fitting, key insertion, etc. That is, the shaft 5 is provided as the rotation axis of the rotor 3. Thus, power can be transmitted between the rotor core 31 and the shaft 5.

[0034] The frame 1 is provided with a first bracket 8 and a second bracket 9 on the axially outer sides of the stator 2 and the rotor 3 in a manner that closes both axial ends of the frame 1. In addition, the first bracket 8 has a first bearing 6, and the second bracket 9 has a second bearing 7. The first bracket 8 supports the shaft 5 rotatably with the aid of the first bearing 6. In addition, the second bracket 9 supports the shaft 5 rotatably with the aid of the second bearing 7. Here, the side close to the shaft end of the shaft 5 to which the axial power of the shaft 5 is transmitted is defined as the load side, and the opposite side to the side is defined as the load opposite side. At this time, the first bracket 8 becomes the load side, and the second bracket 9 becomes the load opposite side. In addition, both may be load sides. In the case where both are load sides, one side is referred to as the load side and the other side is referred to as the load opposite side for convenience.

[0035] The shaft 5 is solid and has a sensor 10 and a transmitter 12 on the radial outer surface. The portion of the shaft 5 where the sensor 10 is mounted is present in a space surrounded by the frame 1, the first bracket 8, and the second bracket 9. More specifically, the sensor 10 is provided in the portion of the shaft 5 between the rotor core 31 and the first bearing 6. Furthermore, the shaft 5 is solid in the direction from the position where the sensor 10 is mounted to the axial core of the shaft 5.

[0036] The sensor 10 is electrically connected to the transmitter 12. Thus, the information detected by the sensor 10 is transmitted to the transmitter 12. The sensor 10 uses, for example, a temperature sensor for measuring temperature, that is, a thermocouple. The sensor 10 generates a voltage according to the temperature of the part where the sensor 10 is installed by using the Seebeck effect. Thus, the temperature of the shaft 5 can be measured. That is, the temperature transmitted from the stator 2, the rotor 3, etc. to the shaft 5 can be measured.

[0037] Here, the operation of the rotating electrical machine 100 will be described. Figure 2 1 is a schematic diagram showing a system in which the rotating electrical machine 100 is incorporated.

[0038] like Figure 2 As shown, the system incorporating the rotating electrical machine 100 includes the rotating electrical machine 100 , a DC power source 40 , and an inverter 50 .

[0039] The DC power supply 40 is electrically connected to the inverter 50, and electric energy is supplied from the DC power supply 40 to the inverter 50. The inverter 50 is electrically connected to the stator coil 4 of the rotating electric machine 100, and a current is supplied to the stator coil 4 by the inverter 50. Specifically, a desired current is supplied to the stator coil 4 by switching control of a switching element 501 included in the inverter 50. The current supplied from the inverter 50 to the rotating electric machine 100 corresponds to the type of the rotating electric machine 100. For example, when the rotating electric machine 100 is a three-phase motor, an AC current is supplied, and when the rotating electric machine 100 is a DC motor, a DC current is supplied.

[0040] The rotating electric machine 100 generates a rotating magnetic field in the rotating electric machine 100 by passing a current through the stator coil 4. The rotor 3 receives the rotating magnetic field and generates torque. The torque is transmitted to the shaft 5, so that power can be transmitted from the shaft end of the shaft 5 to the outside.

[0041] When current is passed through the stator coil 4 to operate the rotating electrical machine 100 as described above, a loss called copper loss is generated in the stator coil 4. In addition, magnetic flux changes occur in the stator core 21 and the rotor core 31 formed of a magnetic body. Eddy currents are generated due to the magnetic flux changes. As a result, losses occur in the stator core 21 and the rotor core 31. In addition, hysteresis losses occur due to magnetic flux changes caused by the hysteresis of the magnetic properties of the magnetic body. These losses increase the temperature of various parts inside the rotating electrical machine 100. Since the temperature of the rotating electrical machine 100 increases compared to the initial state, such as before power is supplied, the degree of temperature rise during operation increases. Therefore, when it is necessary to protect the parts inside the rotating electrical machine 100, it is necessary to reduce the amount of power supplied to the rotating electrical machine 100, stop the supply, etc.

[0042] In the rotating electrical machine according to the first embodiment of the present disclosure, information related to the internal temperature increase of the rotating electrical machine 100 as described above is measured by the sensor 10 and outputted by the transmission unit 12. Figure 3 Explain specifically. Figure 3 This is a schematic diagram of a sensor and a transmission unit according to Embodiment 1 of the present disclosure.

[0043] As described above, the sensor 10 and the transmitter 12 are mounted on the radially outer surface of the portion of the shaft 5 located between the first bearing 6 and the rotor core 31 .

[0044] like Figure 3 As shown, the transmitting unit 12 includes an amplifier circuit unit 121, an A / D conversion circuit unit 122, and a transmitting circuit unit 123. The signal detected by the sensor 10 is amplified by the amplifier circuit unit 121. The amplified signal amplified by the amplifier circuit unit 121 is converted from an analog signal to a digital signal by the A / D conversion circuit unit 122. The digital signal converted by the A / D conversion circuit unit 122 is transmitted to the receiving unit (not shown) by the transmitting circuit unit 123.

[0045] For example, the transmission from the transmission circuit unit 123 to the receiving unit is performed by wireless communication such as Wi-Fi (Wireless Fidelity) (registered trademark) or Bluetooth (registered trademark). For example, when the internal temperature distribution of the rotating electrical machine 100 is derived in a thermal network model, the digital signal received by the receiving unit as described above is used.

[0046] When constructing a thermal network model of the rotating electrical machine 100, a model is usually formed by parts of the rotating electrical machine 100 such as the stator 2 and the rotor 3 where losses occur. When estimating the internal temperature of the rotating electrical machine 100 using temperature information near the rotor core 31, it is preferable to obtain more accurate temperature information of the rotor core 31 in order to improve the estimation accuracy. In addition, when obtaining temperature information near the rotor core 31 and using the constructed thermal network model, it is preferable to obtain temperature information at an appropriate position obtained by considering the way of heat transfer from the rotor core 31 to other parts and heat escaped through air or the like.

[0047] In the past, there was no structure in which a temperature sensor was arranged in the hollow part of a hollow shaft. In addition, in the above-mentioned existing documents, it is not envisaged to arrange a sensor in the hollow part of a hollow shaft and use the information obtained by the sensor to infer the internal state of the motor using a thermal network model. In addition, the shaft is the part of the rotating shaft that becomes the rotating body of the rotating electric machine. Therefore, when a sensor is arranged in a hollow shaft, the strength of the shaft decreases compared to a solid shaft. In order to ensure strength, it is considered to increase the thickness of the hollow shaft, but increasing the thickness of the hollow increases the diameter of the shaft itself, resulting in a large-scale rotating electric machine. In addition, even if a temperature sensor is provided in the hollow part, a temperature distribution will be generated by the amount of the thickness of the hollow shaft, so it is easier to generate a temperature difference than the shaft surface, and because a certain time constant is generated, it will be detected with a delay relative to the start of temperature rise. Therefore, it is sometimes impossible to accurately measure based on the thickness of the hollow shaft. In addition, it is difficult to consider the heat that escapes from the rotor core 31 and the like in the air, and it is difficult to obtain accurate temperature information.

[0048] In addition, for example, when a temperature sensor is set at a certain part of the rotor core 31 to obtain the temperature, it is possible to obtain temperature information related to the part where the temperature sensor is configured. However, when using this temperature information for control, instead of using the measurement information of the rotating electrical machine 100 as a whole, only the measurement information of a specific part is used. Therefore, it may become a control that relies only on the temperature of a specific part without considering the transfer of heat. Specifically, the temperature of a specific part is monitored each time and the temperature information is included in the control at any time, so that it is determined that the temperature of the specific part has exceeded the threshold. And, when it is determined that the threshold has been exceeded, in order to prevent the temperature of the specific part from rising further, actions such as reducing the amount of power supply or stopping the power supply are implemented.

[0049] In the rotary electric machine 100 of the present disclosure, the sensor 10 is mounted on the portion of the solid shaft 5 between the rotor 3 and the first bearing 6. When the shaft 5 is hollow, the rotary electric machine as a whole is enlarged in order to ensure strength. On the other hand, if the shaft 5 is solid, the strength can be ensured without changing the diameter of the shaft 5 or the size of the rotary electric machine 100 as a whole, and the temperature information of the rotor core 31 can be easily obtained. The heat transferred from the rotor core 31 through the shaft 5 is as follows: Figure 4 As shown by the arrow in the middle, the temperature is transmitted to the first bearing 6 and the first bracket 8. Therefore, by installing the sensor 10 on the portion of the shaft 5 between the first bearing 6 and the rotor core 31, the temperature of the shaft 5 adjacent to the rotor 3 can be more accurately measured as the boundary of the thermal network model without considering the branching of heat. In addition, the temperature information obtained by the sensor 10 can be used as a boundary condition to perform calculations with the thermal network model. By performing calculations with the thermal network model, in addition to the control of updating the temperature information at any time, future temperature changes can be predicted and control can be performed based on the prediction, thereby expanding the control range of the rotating electrical machine 100.

[0050] Sensor 10 is attached to the radial outer surface of shaft 5. The portion of shaft 5 where sensor 10 is attached exists in a space surrounded by frame 1, first bracket 8, and second bracket 9. Therefore, heat transferred from shaft 5 via air in the space can be considered.

[0051] Therefore, by attaching the sensor 10 to the shaft 5 and acquiring the temperature as in the first embodiment of the present disclosure, the accuracy of the internal temperature of the rotating electrical machine 100 can be improved with a simple structure.

[0052] In addition, the transmission is performed by wireless communication using the transmission unit 12 having the transmission circuit unit 123. Thus, even when the receiving unit is located in a remote place, communication can be performed without worrying about disconnection, thereby improving communication reliability. In addition, in the case of wireless communication, a mechanism for transmitting between relatively rotating components is not required, and information can be transmitted with a simple structure.

[0053] In addition, the rotor 3 is described as having a rotor core 31 and a shaft 5, but it can also be configured to have a magnet and a secondary conductor (not shown) inside the rotor core 31 or on the radial outer surface of the rotor core 31, or it can be configured to have a magnet and a secondary conductor (not shown) inside the rotor core 31 and on the radial outer surface of the rotor core 31. By configuring the structure to have a magnet, in addition to being able to improve the accuracy of the internal temperature of the rotating electrical machine 100, the output torque can also be improved. In addition, in the case of having a magnet, it can also be configured to have a structure in which an end plate for holding a magnet or the like is provided at the axial end of the rotor core 31. By holding the magnet on the end plate, the magnet can be prevented from flying out.

[0054] in addition, Figure 1 as well as Figure 4 The first bearing 6 and the second bearing 7 are shown as ball bearings, but sliding bearings can also be used. The shaft 5 can also be supported by sliding bearings, and the heat from the shaft 5 is transferred to each bearing and each housing as described above. This also has the effect of improving the accuracy of the internal temperature of the rotating electrical machine 100.

[0055] In addition, although the sensor 10 is installed at the portion of the shaft 5 between the first bearing 6 and the rotor core 31, the sensor 10 may be installed at the portion of the shaft 5 between the second bearing 7 and the rotor core 31. Since heat is transferred from the rotor core 31 to the shaft 5 on the opposite side to the load as on the load side, temperature information can be obtained, and the accuracy of the internal temperature of the rotating electrical machine 100 can be improved.

[0056] Furthermore, although the system in which the rotating electric machine 100 is installed has been described as including the rotating electric machine 100, the DC power supply 40, and the inverter 50, the inverter 50 may not be provided depending on the type of the rotating electric machine 100. For example, when the motor is a rotating electric machine such as a general-purpose three-phase motor or a DC motor that is directly connected to the power supply of the system without the inverter 50 to operate, the system can be configured without providing the inverter 50.

[0057] In addition, the sensor 10 and the transmitter 12 are set to be adjacent to each other, but they are not necessarily limited to this form. For example, it is also possible that: the sensor 10 is provided between the first bearing 6 and the rotor core 31, and the transmitter 12 is different from the sensor 10 arranged inside the space surrounded by the frame 1, the first bracket 8 and the second bracket 9, but is arranged in the frame 1, each bracket and the shaft 5 and other parts outside the space. As a result, it is not affected by the metal parts constituting the rotating electrical machine 100, and information can be transmitted without being affected by the surrounding environment. In this case, for example, it is sufficient to connect the sensor 10 and the transmitter 12 with a lead wire. In the above cases, the accuracy of the internal temperature of the rotating electrical machine 100 can also be improved.

[0058] In addition, it is described that the transmitting unit 12 uses the transmitting circuit unit 123 to transmit the signal to the receiving unit by wireless communication, but it is also possible to follow a communication standard other than the above-described case or a non-standard. In addition, it is described that the signal is amplified by the amplifier circuit unit 121, but it is not necessarily amplified, and the signal can be passed as it is. In addition, it is described that the analog signal is converted into a digital signal by the A / D conversion circuit unit 122, but it is also possible to transmit the analog signal by wireless communication. In the above cases, the accuracy of the internal temperature of the rotating electrical machine 100 can also be improved.

[0059] In addition, the sensor 10 is described as a thermocouple as a temperature sensor, but a strain gauge or a magnetic sensor may be used instead of or in combination with the temperature sensor. Since the amount of strain on the surface of the shaft is greater than the amount of strain in the hollow of the shaft, the amount of strain can be obtained more accurately by configuring it on the surface of the shaft 5 and measuring it. In addition, the magnetic sensor is easier to detect on the surface of the shaft 5 than in the hollow of the hollow shaft, and more accurate measurement can be performed.

[0060] In addition, a vibration sensor or a pressure sensor may be used instead of the above-mentioned sensors or in combination with the above-mentioned sensors. It has been described that the internal temperature distribution of the rotating electrical machine 100 is derived using a thermal circuit model, but when using a sensor other than a temperature sensor, a physical model of the rotating electrical machine 100 corresponding to the physical quantity measured by each sensor may be used instead of the thermal circuit model. Alternatively, a physical model of the rotating electrical machine 100 corresponding to the physical quantity measured by each sensor may be used in combination with the thermal circuit model. In this way, the internal distribution state of the rotating electrical machine 100 can be derived, and the accuracy of the internal temperature of the rotating electrical machine 100 can be improved.

[0061] Implementation method 2.

[0062] A rotating electrical machine according to a second embodiment of the present disclosure will be described. Figures 1 to 4 The same reference numerals indicate the same or corresponding structures, and their descriptions are omitted. Only the parts different from the first embodiment will be described. Figure 5 2 is a longitudinal sectional view showing a rotating electrical machine according to Embodiment 2 of the present disclosure. Figure 5 Axis 5 of FIG. 5 shows a state in which the image is not cut.

[0063] In the rotating electrical machine 100 according to the second embodiment of the present disclosure, as Figure 5 As shown, the portion of the shaft 5 between the first bearing 6 and the rotor core 31 has a recess 51 that is recessed radially inward from the radially outermost surface of the shaft 5. For example, the recess 51 is formed only in a portion of the rotation direction of the shaft 5 using a machining center or the like. In addition, the sensor 10 is accommodated in the radially outer surface of the recess 51. The shaft 5 on which the sensor 10 is provided is solid from the sensor 10 to the axial core of the shaft 5. Although it is sufficient to be solid from the sensor 10 to the axial core of the shaft 5, the strength is further improved when the cylindrical portion of the shaft 5 with a radius equal to the distance from the axial core to the position where the sensor 10 is provided is solid.

[0064] The shaft 5 has a shaft groove 52 on the radially outer surface. That is, the shaft groove 52 has a structure in which a groove is formed, which is recessed radially inward from the vicinity of the recess 51 of the shaft 5 and extends axially to the anti-load side.

[0065] The transmitter 12 is mounted on the opposite side of the load of the shaft 5 and is fastened to the shaft 5. Therefore, the transmitter 12 is linked to the rotation of the shaft 5. With such a structure, the sensor 10 located on the load side with the rotor 3 interposed therebetween is connected to the transmitter 12 located on the opposite side of the load. More specifically, the transmitter 12 has a lead wire receiving portion 13. And the lead wire receiving portion 13 is connected to the lead wire 11. Therefore, the lead wire 11 is wired to the shaft groove portion 52 of the shaft 5 and is led out from the axial end portion of the shaft 5 on the opposite side of the load. The lead wire receiving portion 13 is connected to a terminal for receiving a signal from a thermocouple and a terminal of the transmitter 12.

[0066] The signal detected by the sensor 10 is transmitted via the lead wire 11. The transmitted signal is received by the lead wire receiving unit 13 and handed over to the transmitter 12. Then, the transmitter 12 converts the signal by the A / D conversion circuit unit 122 and the transmission circuit unit 123 and transmits it by wireless communication.

[0067] The rotating electric machine 100 of the second embodiment of the present disclosure is a structure in which the sensor 10 is housed in the recess 51 of the shaft 5. As a result, the influence of the sensor 10 being exposed to the air inside the rotating electric machine 100 can be reduced. As a result, the information of the surface of the shaft 5 adjacent to the rotor core 31 can be obtained with high accuracy. In addition, the shaft 5 is solid from the position where the sensor 10 is installed to the shaft core, and the strength of the shaft 5 is ensured. Therefore, there is no need to increase the diameter of the shaft 5, and there is no need to change the overall size of the rotating electric machine 100. In addition, when the cylindrical portion with the distance from the position where the sensor 10 is installed to the shaft core as the radius is solid, the temperature distribution of the thickness will not be generated like a hollow shaft, and the start of temperature rise can be detected earlier. Therefore, the accuracy of the internal temperature of the rotating electric machine 100 can be improved with a simple structure.

[0068] In addition, in Embodiment 2 of the present disclosure, it is described that the transmitting unit 12 is arranged on the opposite side of the load of the shaft 5, but the present invention is not limited to this form, and the transmitting unit 12 can also be arranged on the load side in the same way as in Embodiment 1 of the present disclosure. In this case, when wireless communication is set as in Embodiment 1, the lead wire 11 and the shaft groove portion 52 and the lead wire receiving portion 13 required to be attached to the lead wire 11 are not required, so information can be obtained with a simpler structure. In addition, as another form, it is also possible to set the transmitting unit 12 to the axial outside of the first bracket 8. In this case, the axial length of the shaft groove portion 52 for leading out the lead wire 11 can be shortened, and the processed portion of the shaft 5 can be reduced.

[0069] In addition, the form of making the lead wire 11 follow the shaft groove portion 52 is described, but the component can also be set in a manner that covers the radial outer surface of the shaft groove portion 52 and the lead wire 11. In this way, the lead wire 11 can be held. In the case of setting the component, the radial outermost surface of the component can be configured to be located at a position that is equal to the radial outermost surface of the shaft 5 or radially inward than the radial outermost surface of the shaft 5. Thus, it will not become an obstacle when the shaft 5 is configured in each bearing, and it is easy to assemble. In addition, with regard to the component, a material that is heavier than the material of the shaft 5 that exists when the shaft groove portion 52 is not set in the shaft 5 is selected, thereby improving the resistance to centrifugal force.

[0070] In addition, the following structure may be adopted, that is, a hole for the lead wire 11 is provided through a part of the solid shaft 5, so that the lead wire 11 is passed through the hole. In addition, regarding the recessed portion 51 of the shaft 5, it is described that the recessed portion 51 is formed only in a part in the rotation direction, but it is not necessarily limited to this form. For example, it may be configured so that the outer diameter of the shaft is reduced in the range of the entire circumference of the shaft 5. In the above case, the same effect as described above is also achieved.

[0071] Implementation method 3.

[0072] A rotating electrical machine according to a third embodiment of the present disclosure will be described. Figures 1 to 5 The same reference numerals indicate the same or corresponding structures, and their descriptions are omitted. Only the parts different from Embodiment 1 and Embodiment 2 will be described. Figure 6 This is a perspective view in which a part of the shaft of the rotating electrical machine according to Embodiment 3 of the present disclosure is cut away. Figure 7 This is a perspective view showing a modified example in which a part of the shaft of the rotating electrical machine according to the third embodiment of the present disclosure is cut away. In addition, for the sake of convenience of explanation, only components necessary for explanation are shown in the figure, and other structures are omitted.

[0073] Specifically, Figure 6 The figure is a diagram obtained by cutting the shaft 5 at an axial position where the sensor 10 is housed, with a plane perpendicular to the axial direction of the shaft 5. For the convenience of explanation, a part of the structure is omitted. Figure 6 As shown, the sensor 10 is housed in a recess 51 formed in the shaft 5. Furthermore, a holding member 14 is provided on the radially outer side of the sensor 10.

[0074] For example, the radial outer surface of the holding member 14 is formed into an arc shape using a material such as metal or resin, and the sensor 10 is held from the radial outside. The radial outer surface of the holding member 14 holding the sensor 10 is preferably aligned with the radial outer surface of the shaft 5 or located inside the radial outer surface of the shaft 5. This allows for smooth assembly. The holding member 14 itself is arranged on the shaft 5 in a manner that the shaft 5 restricts movement in the axial direction.

[0075] When the rotating electrical machine 100 operates and the rotor 3 rotates, centrifugal force acts on the rotating portion of the rotating electrical machine 100. The centrifugal force also acts on the sensor 10 provided on the shaft 5, so the sensor 10 tends to move radially outward as the rotating electrical machine 100 rotates.

[0076] In order to ensure the sensing accuracy obtained by the sensor 10 , the sensor 10 needs to be securely attached to the shaft 5 that is the sensing object even when centrifugal force or the like due to rotation acts on the sensor 10 .

[0077] In the third embodiment of the present disclosure, the holding member 14 is provided adjacent to the radially outer side of the sensor 10. Therefore, the centrifugal force applied to the sensor 10 is transmitted to the holding member 14. On the other hand, the holding member 14 is Figure 6 As shown, the sensor 10 is formed in an arc shape, and therefore, it is deformed by the Young's modulus corresponding to the raw material and becomes a shape that bulges slightly radially outward. That is, when the retaining member 14 is configured and sized to withstand centrifugal force, the sensor 10 can be retained in a state where the retaining member is elastically deformed. Thus, by arranging the sensor 10 on the radial outer surface of the shaft 5 and arranging the retaining member 14 radially outward of the sensor 10, it is possible to suppress the sensor 10 from moving, separating from the shaft 5, and flying radially outward of the shaft 5 due to centrifugal force. Thus, information can be stably acquired even during rotation.

[0078] Therefore, in addition to the effect of improving the accuracy of the internal temperature of the rotating electrical machine 100 with a simple configuration similar to the first and second embodiments of the present disclosure, it is possible to suppress a decrease in the estimation accuracy of the internal temperature of the motor.

[0079] In the third embodiment of the present disclosure, the recess 51 is provided in a part of the shaft 5, the sensor 10 is arranged in the recess 51, and the radial outer surface of the sensor 10 is covered by the retaining member 14, but the present invention is not limited to this. The retaining member 14 can be arranged radially outward of the sensor 10, for example, Figure 7 As shown, the structure is such that the diameter of the shaft 5 is reduced in the concave portion 51 over the entire circumference of the shaft 5 and the cylindrical retaining member 14 is arranged radially outside the concave portion 51. When the cylindrical portion having a radius equal to the distance from the position where the sensor 10 is mounted to the shaft core is solid, temperature distribution corresponding to the thickness will not occur as in the case of a hollow shaft, and the start of temperature rise can be detected earlier.

[0080] in addition, Figure 6The arc-shaped retaining member 14 shown may be shaped so long as it is restricted radially inward of the radially outer surface of the shaft 5, and the radially outer side may be made flat. In this case, the sensor 10 can also be prevented from jumping out radially outward.

[0081] Implementation method 4.

[0082] A rotating electrical machine according to a fourth embodiment of the present disclosure will be described. Figures 1 to 7 The same reference numerals indicate the same or corresponding structures, and their descriptions are omitted. Only the parts different from Embodiments 1 to 3 will be described. Figure 8 This is a cross-sectional view of the main part of the rotating electric machine according to Embodiment 4 of the present disclosure, that is, the axial position of the shaft, cut along a plane perpendicular to the axial direction of the shaft 5. For convenience of explanation, a part of the structure is omitted.

[0083] In the fourth embodiment of the present disclosure, the sensor 10 is accommodated in the recess 51 of the shaft 5. At this time, the sensor 10 is fixed to the recess 51 of the shaft by the insulating member 15. The insulating member 15 is composed of, for example, epoxy glass agent. The sensor 10 is fixed to the shaft 5 via the insulating member 15, so that the sensor 10 and the shaft 5 are electrically insulated. In addition, the insulating member 15 is configured so that the sensor 10 does not leave the shaft 5 when the rotating electric machine 100 rotates.

[0084] As described in Embodiment 1 of the present disclosure, the rotating electric machine 100 generates a rotating magnetic field in the rotating electric machine 100 by passing a current through the stator coil 4. Receiving this rotating magnetic field, a torque is generated in the rotor 3. At this time, a shaft voltage is sometimes generated in the shaft 5 of the rotating electric machine 100. This is because a counter electromotive force is generated in the shaft according to the current conduction pattern of the current supplied to the stator coil 4.

[0085] The above-mentioned shaft voltage is generated when the shaft 5 and the sensor 10 are in direct contact and thus conductive without passing through the insulating member 15. At this time, the shaft 5 and the sensor 10 are at the same potential because they are conductive. In addition, when the sensor 10 is conductive to the transmitting part 12, for example, by means of the lead wire 11 and the receiving part (not shown) is electrically connected to the transmitting part 12, the voltage of the receiving part (not shown) may increase abnormally. In addition, if the shaft voltage becomes higher than the withstand voltage value of the receiving part at this time, the circuit for measuring the sensor signal may malfunction. Therefore, it is best to ensure insulation between the shaft 5 and the sensor 10.

[0086] In Embodiment 4 of the present disclosure, the sensor 10 is fixed to the shaft 5 via the insulating member 15. That is, insulation is ensured between the shaft 5 and the sensor 10. Therefore, even when the shaft voltage described above is generated, the sensor 10 can continue measurement without being conductive.

[0087] Therefore, according to the fourth embodiment of the present disclosure, in addition to the effect of improving the accuracy of the internal temperature of the rotating electrical machine 100 with the same simple structure as the first to third embodiments, it is also possible to achieve the effect of maintaining a stable measurement state.

[0088] In addition, in the fourth embodiment of the present disclosure, the recess 51 is illustrated as being formed over the entire circumference of the shaft 5, but the present invention is not limited thereto, and a portion of the shaft 5 may be cut radially inward. In any form, since the shaft 5 is solid from the sensor 10 attached to the shaft 5 to the axial core of the shaft 5, the strength of the shaft 5 is ensured.

[0089] In addition, although it is described that epoxy glass is disposed between the shaft 5 and the sensor 10 as an insulating member, the present invention is not necessarily limited to this form. For example, the sensor 10 can be fixed to the shaft 5 by using a resin material or the like, and the sensor 10 and the shaft 5 can be insulated via the insulating member. In this case, the same effect as described above can be achieved.

[0090] Implementation method 5.

[0091] A rotating electrical machine system according to a fifth embodiment of the present disclosure will be described. Figures 1 to 8 The same reference numerals indicate the same or corresponding structures, and their descriptions are omitted. Only the parts different from Embodiments 1 to 4 will be described. Fig. 9 This is a schematic diagram of a rotating electrical machine system according to Embodiment 5 of the present disclosure. Fig.10 It is a hardware configuration diagram of a rotating electrical machine system according to Embodiment 5 of the present disclosure. Fig.11 It is a diagram showing a control flow chart according to Embodiment 5 of the present disclosure. Fig.12 It is a diagram showing a current waveform according to Embodiment 5 of the present disclosure.

[0092] like Fig. 9 As shown in the figure, the drive system in which the rotating electric machine 100 is installed includes the rotating electric machine 100, the DC power supply 40, the inverter 50, and the control unit 60. The DC power supply 40 supplies electric energy to the inverter 50, and the switching element 501 in the inverter 50 is switched, so that the current of the sine wave or the like is supplied to the stator coil 4 in the rotating electric machine 100. The specific connection relationship between the DC power supply 40, the inverter 50, and the rotating electric machine 100 is the same as that described in the first embodiment, and therefore the description thereof is omitted.

[0093] The rotating electrical machine system in the fifth embodiment of the present disclosure includes a control unit 60. The control unit 60 includes a receiving unit that receives a signal from the sensor 10. The control unit 60 sends a control signal to the inverter 50 based on the signal received from the sensor 10. The inverter 50 receives the control signal from the control unit 60 and supplies current to the rotating electrical machine 100 based on the control signal.

[0094] The control unit 60 further includes an estimation unit (not shown) that derives the internal state of the rotating electrical machine 100. The estimation unit estimates and calculates the internal state of the rotating electrical machine 100 using, for example, a network model. The control signal described above is generated based on the calculation performed by the estimation unit.

[0095] The control unit 60 is as follows Fig.10 As shown, there is a processor 601 and a storage unit 602. The processor 601 executes the program stored in the storage unit 602 to perform the above-mentioned processing. Here, the storage unit 602 is composed of a memory storing required parameters, a program written with the above-mentioned processing, etc. The processor 601 is composed of a processor logically constructed in a hardware circuit such as a microcomputer, a DSP (Digital Signal Processor) and an FPGA (Field Programmable Gate Array). In addition, multiple processors 601 and multiple storage units 602 can also perform the above-mentioned functions in cooperation with each other.

[0096] use Fig.11 The operation of the control unit is further described. In step 1 (S1), a torque command value is received from a superior control unit (not shown). In step 2 (S2), a current command value corresponding to the torque command value is calculated. In step 3 (S3), sensor information is obtained from the sensor 10 mounted on the rotating electric machine 100 via the transmission unit 12 using the control unit 60. In step 4 (S4), the internal state of the rotating electric machine 100 is estimated based on the acquired sensor information. In step 5 (S5), the maximum value of the current allowed in the rotating electric machine 100 is calculated based on the internal state estimation result. In step 6 (S6), the maximum value of the current is compared with the above-mentioned current command value. When the former is larger, a current command corresponding to the torque command is generated (step 7 (S7)), and when the latter is larger, a current command corresponding to the maximum value of the current is generated. In the final step, current is supplied to the rotating electric machine 100 based on the generated current command, i.e., the control signal. The rotating electric machine 100 is driven by the above-mentioned steps 1 to 7.

[0097] Next, use Fig.12 This section explains the difference in command torque caused by the presence or absence of temperature information. The horizontal axis represents time and the vertical axis represents current. Fig.12The solid line represents the current waveform when there is temperature information, and the dotted line represents the current waveform when there is no temperature information.

[0098] In the case of temperature information, if the temperature of the object drops, if the current in the rotating electrical machine 100 is within the physically allowed current, a command to increase the current command value to increase the torque can be applied. On the other hand, in the case of no temperature information, even if the temperature of the object drops, it is impossible to grasp the situation that the temperature has dropped with high accuracy. Therefore, even if the current command value is maintained or increased, it is lower than the increase in the case of the above-mentioned temperature information. Therefore, it is better to perform control taking the temperature information into consideration. In addition, it is better to obtain the temperature information used for control with high accuracy.

[0099] Conventional methods have only installed sensors on rotating electrical machines and monitored sensor signals to perform fault diagnosis and measurement at any time. That is, there has been no research into control using sensor information to change control operating points of rotating electrical machine 100 such as torque, rotation speed, and output.

[0100] In Embodiment 5 of the present disclosure, the sensor information of the sensor 10 is sent to the control unit 60, and the control unit 60 generates a control signal based on the sensor information of the sensor 10. This enables high-precision control. In addition, the internal temperature distribution of the rotating electrical machine 100 is derived based on the measured temperature of the shaft 5 in combination with the thermal network model. According to the internal temperature distribution, the temperature of the parts having temperature thresholds, such as the stator coil 4, the first bearing 6, and the second bearing 7, can be grasped. Therefore, by comparing the derived temperature of each part with the temperature threshold of the part, the control unit 60 generates a control signal that further allows the control action point to change to allow heating and temperature rise in each part. The control signal is generated based on the internal temperature distribution.

[0101] Thus, the rotating electrical machine 100 can change the control action point based on the information detected by the sensor 10. In addition, by using the measured temperature of the shaft 5 and the thermal circuit model, it is possible to obtain information corresponding to the boundary of the thermal network model, so that the estimation accuracy of the internal state of the rotating electrical machine 100 can be improved compared to the previous case of using only the physical model. By improving the estimation system of the internal state, the rotating electrical machine 100 can be operated until it approaches the range of the temperature threshold of each motor part. In addition, the temperature of the above-mentioned various parts does not necessarily have to be the temperature information at that moment. The temperature distribution at a future moment can be derived using the thermal network model, and the temperature information at that moment can also be used.

[0102] Therefore, in addition to the effect of improving the accuracy of the internal temperature of the rotating electrical machine 100 with the same simple structure as the first to fourth embodiments, the fifth embodiment of the present disclosure also has the effect of expanding the operating range of the rotating electrical machine 100 .

[0103] In addition, in the fifth embodiment of the present disclosure, the rotating electric machine 100 is described as driving, but the present invention is not necessarily limited to this form, and the rotating electric machine 100 may also be in a form of generating electricity. In the case of generating electricity, the rotating electric machine 100 converts mechanical energy into electrical energy, and the electrical energy is stored in the DC power supply 40 via the inverter 50. In this case, the same effect is achieved.

[0104] Implementation method 6.

[0105] A rotating electrical machine according to a sixth embodiment of the present disclosure will be described. Figures 1 to 12 The same reference numerals indicate the same or corresponding structures, and their descriptions are omitted. Only the parts different from Embodiments 1 to 5 will be described. Fig.13 It is a longitudinal sectional view showing a rotating electrical machine according to Embodiment 6 of the present disclosure.

[0106] like Fig.13 As shown in FIG. 1 , the diameter of the shaft insertion hole on the axial end surface of the rotor core 31 is formed to be relatively large. Specifically, electromagnetic steel sheets having relatively large diameters of the shaft insertion holes are stacked on the axial end side of the rotor core 31. As a result, a space is generated in a portion of the radial direction between the rotor core 31 and the shaft 5. Fig.13 As shown, the sensor 10 is installed in a manner confined within the space between the rotor core 31 and the shaft 5 .

[0107] Thus, the temperature can be measured at a position closer to the rotor core 31. In addition, the influence of the sensor 10 being exposed to the air inside the rotating electrical machine 100 can be reduced. Thus, information on the surface of the shaft 5 close to the rotor core 31 can be obtained with high accuracy. In addition, even when the distance between the rotor core 31 and the first bearing 6 is short, a place for installing the sensor 10 can be ensured.

[0108] Therefore, in addition to being able to improve the accuracy of the internal temperature of the rotating electrical machine 100 with the same simple structure as in the first to fifth embodiments, the sixth embodiment of the present disclosure can also install the sensor 10 when the shaft 5 has a short axial length, and can also obtain information more accurately.

[0109] In addition, although the diameter of the shaft insertion hole of the laminated steel plate at the end of the rotor core 31 is larger, it is also possible to increase only a part of the diameter according to the size of the sensor 10 instead of increasing the diameter. In addition, when using the rotor core 31 that has not been laminated or after laminating the same laminated steel plates, processing can be performed to provide a space for installing the sensor 10. In addition, it is described that the sensor 10 is installed in a manner limited to the space between the rotor core 31 and the shaft 5, but the space may be a size that accommodates a part of the sensor 10. In the above cases, the same effects as those described above are also achieved.

[0110] In addition, each embodiment can be freely combined, appropriately modified, or omitted.

[0111] Description of Reference Numerals

[0112] 2. stator; 3. rotor; 4. stator coil; 5. shaft; 6. first bearing; 7. second bearing; 8. first bracket; 9. second bracket; 10. sensor; 11. lead wire; 12. transmitter; 14. retaining member; 15. insulating member; 21. stator core; 31. rotor core; 40. DC power supply; 50. inverter; 51. recess; 52. shaft groove; 60. control unit; 100. rotating motor; 501. switching element; 601. processor; 602. storage unit.

Claims

1. A rotating electrical machine system, wherein: The rotating electrical machine system includes a rotating electrical machine and a control unit that controls electric power supplied to the rotating electrical machine. The rotating electric machine has a stator, a rotor, a shaft, a bracket and a sensor, The rotor is rotatably arranged radially inside the stator. The shaft is provided as the rotation axis of the rotor, The bracket supports the shaft via a bearing so as to be rotatable relative to the stator. The sensor is disposed on the outer diameter side surface of a portion of the shaft between the rotor and the bearing to measure the temperature of the shaft. The control unit estimates the internal temperature distribution of the rotating electrical machine as the internal state of the rotating electrical machine using the thermal network model, based on a thermal network model for deriving the internal temperature distribution of the rotating electrical machine and temperature information of a portion of the shaft between the rotor and the bearing acquired by the sensor, using the temperature information as a boundary condition of the thermal network model, and using the thermal network model. The shaft has a groove portion which is recessed radially inward of the shaft and extends in the axial direction. A lead wire is disposed in the groove portion, and the lead wire transmits information measured by the sensor.

2. The rotating electrical machine system according to claim 1, wherein: The control unit estimates an internal state of the rotating electric machine, and controls energization of the rotating electric machine based on estimated information.

3. The rotating electrical machine system according to claim 1, wherein: The control unit predicts temperature changes inside the rotating electrical machine using the thermal network model.

4. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The sensor is provided separately from the rotor on an outer diameter side surface of a portion of the shaft between the rotor and the bearing.

5. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The rotor and the stator are surrounded by the bracket and the cylindrical frame, and the bracket is arranged at both axial ends of the frame. The sensor is arranged between the rotor and the bearing in a space surrounded by the frame and the bracket.

6. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The sensor is located in a space between the rotor and the shaft in radial directions.

7. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The shaft is solid in a direction from a position where the sensor is mounted toward the shaft center.

8. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The radial outer surface of the shaft has a recess between the rotor and the bearing, The sensor is accommodated in the recess.

9. The rotating electrical machine system according to claim 8, wherein: The shaft has a radially extending retaining member covering the sensor.

10. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The sensor is disposed directly on a radially outer surface of a portion of the shaft between the rotor and the bearing.

11. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The sensor is mounted on the shaft via an insulating member.

12. The rotating electrical machine system according to any one of claims 1 to 3, wherein: The rotating electrical machine includes a transmitting unit that acquires and transmits a signal from the sensor. The control unit performs control based on the information from the transmission unit.

13. The rotating electrical machine system according to claim 12, wherein: The control unit includes a receiving unit and an inferring unit. The receiving unit receives the signal from the sending unit, The estimating unit estimates the internal state of the rotating electrical machine based on the information from the receiving unit. The control unit performs control based on the information estimated by the estimation unit.

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