Motor control device and motor control method

Abstract

A motor control device according to an aspect of the present disclosure is for controlling a motor and comprises: a rotation control unit that controls the rotational torque of the motor to a predetermined torque, causes the motor to rotate, and controls the rotational torque to a low torque lower than the predetermined torque until a predetermined period elapses after starting of the motor is initiated; and an abnormality detection unit that detects abnormality of the motor on the basis of the rotation state of the motor when the rotational torque is controlled to the low torque and the rotation state of the motor when the rotational torque is controlled to the predetermined torque.

Description

Motor control device and motor control method

[0001] The present disclosure relates to a motor control device and a motor control method.

[0002] Japanese Patent Application Laid-Open No. 2015-146715 discloses an electronic device equipped with a fan motor. When the fan motor does not rotate after the electronic device is powered on, a rotation failure is detected.

[0003] It is desirable to detect motor deterioration before the motor actually fails to rotate.

[0004] The present invention aims to solve the above-mentioned problems.

[0005] A first aspect of the present disclosure is a motor control device that controls a motor, and includes a rotation control unit that controls the rotational torque of the motor to a predetermined torque to rotate the motor, and controls the rotational torque to a low torque lower than the predetermined torque until a predetermined period of time has elapsed since the motor begins to start up, and an abnormality detection unit that detects an abnormality in the motor based on the rotational state of the motor with the rotational torque controlled to the low torque and the rotational state of the motor with the rotational torque controlled to the predetermined torque.

[0006] A second aspect of the present disclosure is a motor control method for controlling a motor, comprising: a rotation control step of controlling the rotational torque of the motor to a predetermined torque to rotate the motor, and controlling the rotational torque to a low torque lower than the predetermined torque until a predetermined period of time has elapsed since the start of activation of the motor; and an abnormality detection step of detecting an abnormality in the motor based on the rotational state of the motor with the rotational torque controlled to the low torque and the rotational state of the motor with the rotational torque controlled to the predetermined torque.

[0007] FIG. 1 is a diagram illustrating the configuration of an electronic device having a motor and a motor control device according to an embodiment. FIG. 2 is a diagram illustrating changes in the rotational state of the motor over time. FIG. 3 is a diagram illustrating abnormality detection based on the rotational state of the motor. FIG. 4 is a flowchart illustrating a processing procedure related to a motor control method according to an embodiment. FIG. 5 is a diagram illustrating changes in the rotational state of the motor over time. FIG. 6 is a diagram illustrating abnormality detection based on the rotation speed of the motor. FIG. 7 is a diagram illustrating changes in the rotational state of the motor over time. FIG. 8 is a diagram illustrating abnormality detection based on the rotation speed of the motor.

[0008] Japanese Patent Application Laid-Open Publication No. 2015-146715 discloses that when an electronic device is powered on and the fan motor does not rotate, a rotation failure is detected. If a rotation failure of the fan motor is detected, the torque of the fan motor is increased after the electronic device is restarted. The degree of deterioration of the fan motor is determined based on the time required for the fan motor to rotate and the torque at which the fan motor rotates.

[0009] If the fan motor does not rotate after the power is turned on, it is likely that the fan motor has already deteriorated significantly. If the torque returns to normal from the increased torque state, or if the electronic device is turned off and then turned on again, the fan motor may fail to rotate again.

[0010] This can disrupt work processes using electronic devices, and it may become necessary to immediately replace or repair the fan motor, further disrupting work processes. It is desirable to detect motor deterioration before the motor actually fails to rotate.

[0011] FIG. 1 is a diagram illustrating the configuration of an electronic device 40 having a motor 10 and a motor control device 20 according to one embodiment. The electronic device 40 is, for example, a personal computer. The electronic device 40 has the motor 10, the motor control device 20, a storage device 50, a sensor 60, and a switch 70. The electronic device 40 starts up when power is supplied from a power source 80. The electronic device 40 is connected to a display device 90 that displays information output from the motor control device 20. The electronic device 40 may include the display device 90.

[0012] 1 , motor 10 is provided as a fan motor for electronic device 40. The fan motor cools the inside of electronic device 40 by discharging heat generated inside electronic device 40 to the outside together with a fluid. Motor 10 rotates according to rotational torque M determined by motor control device 20.

[0013] The sensor 60 detects the rotation state of the motor 10. The sensor 60 outputs a sensor signal related to the detected rotation state of the motor 10 to the motor control device 20. In this embodiment, the sensor 60 is a lock sensor. The sensor 60 detects whether the motor 10 is rotating as the rotation state of the motor 10.

[0014] The switch 70 switches the power supply from the power supply 80 to the electronic device 40. When the switch 70 is turned on, power is supplied from the power supply 80 to each part of the electronic device 40, such as the motor control device 20 and the storage device 50. When the switch 70 is turned off, the power supply from the power supply 80 to each part of the electronic device 40 is cut off.

[0015] The motor control device 20 controls the motor 10. The motor control device 20 includes a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). In other words, the motor control device 20 includes processing circuitry. Note that the processor of the electronic device 40 is not limited to the control function of the motor 10 as the motor control device 20, but can also perform various functions of the electronic device 40.

[0016] The storage device 50 includes volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory) or flash memory. The volatile memory is used as working memory for the processor. The non-volatile memory stores programs executed by the processor and other necessary data.

[0017] Motor control device 20 has rotation control unit 110, rotation state determination unit 120, abnormality detection unit 130, power supply control unit 140, and display control unit 150. Motor control device 20 executes a program stored in storage device 50, thereby realizing rotation control unit 110, rotation state determination unit 120, abnormality detection unit 130, power supply control unit 140, and display control unit 150.

[0018] At least some of the rotation control unit 110, the rotation state determination unit 120, the abnormality detection unit 130, the power supply control unit 140, and the display control unit 150 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), or an electronic circuit including discrete devices.

[0019] The rotation control unit 110 controls the rotation torque M of the motor 10 to a predetermined torque Ms to rotate the motor 10. However, as will be described later with reference to FIG. 2 , until a predetermined period Tx has elapsed since the start of activation of the motor 10, the rotation control unit 110 controls the rotation torque M to a low torque Mi that is lower than the predetermined torque Ms. The control of the rotation torque M is achieved by PWM (Pulse Width Modulation) control. The predetermined period Tx is measured using a clock circuit, a timer circuit, and the like (not shown).

[0020] The rotation state determination unit 120 receives a sensor signal output from the sensor 60. Based on the sensor signal, the rotation state determination unit 120 determines the rotation state of the motor 10. In this embodiment, the rotation state determination unit 120 determines whether the motor 10 is rotating.

[0021] The rotation state determination unit 120 determines the rotation state of the motor 10 in which the rotation torque M is controlled to the above-mentioned low torque Mi after the start of startup of the motor 10. The rotation state determination unit 120 determines the rotation state of the motor 10 in which the rotation torque M is controlled to the above-mentioned predetermined torque Ms after a predetermined period Tx has elapsed since the start of startup of the motor 10.

[0022] The abnormality detection unit 130 detects an abnormality in the motor 10 based on the rotation state of the motor 10 when the rotational torque M is controlled to a low torque Mi and the rotation state of the motor 10 when the rotational torque M is controlled to a predetermined torque Ms. The abnormalities of the motor 10 detected by the abnormality detection unit 130 include a first type abnormality in which a rotational malfunction of the motor 10 is latent, and a second type abnormality in which a rotational malfunction of the motor 10 is apparent. Detection of an abnormality in the motor 10 based on the rotational state of the motor 10 will be described later using FIG. 3 .

[0023] The power supply control unit 140 turns off the switch 70 to cut off the power supply from the power source 80 to the electronic device 40. If a second type of abnormality occurs in which the motor 10 is not rotating properly, the electronic device 40 cannot dissipate heat. In this case, components of the electronic device 40 may break down due to high heat. To prevent such a breakdown, the power supply control unit 140 turns off the switch 70 when a second type of abnormality occurs.

[0024] The display control unit (alert control unit) 150 can output a notification regarding maintenance of the motor 10 to the display device 90. The display device 90 is, for example, a liquid crystal display, an organic EL display, or the like. The notification regarding maintenance of the motor 10 is, for example, displayed on the display unit (alert unit) of the display device 90, or is notified from a speaker (alert unit) of the display device 90. If the display device 90 is a lamp (alert unit) such as an indicator, the above-mentioned notification may be output by changing the illumination state of the lamp.

[0025] During normal operation of the electronic device 40, the rotation torque M of the motor 10 is controlled to a predetermined torque Ms. If the motor 10 rotates in this state, then a rotation failure of the motor 10 has not occurred.

[0026] However, in reality, there is a possibility that the motor 10 is deteriorating. In this case, for example, the next time the motor 10 is restarted after stopping its rotation, a rotation failure of the motor 10 may occur. In other words, even if the motor 10 is rotating, there is a possibility that a rotation failure of the motor 10 is latent. When the deterioration of the motor 10 progresses and a rotation failure of the motor 10 is latent, the abnormality detection unit 130 detects this state as the above-mentioned first type abnormality of the motor 10.

[0027] For example, let us assume that the power supply to the electronic device 40 is cut off, causing the rotation of the motor 10 to stop overnight, for several days, or for a long period of time, and then the power supply to the electronic device 40 is restarted, causing the motor 10 to start again. Generally, the coefficient of static friction is greater than the coefficient of kinetic friction. Therefore, the friction of the bearings in the motor 10 at startup is greater than the friction during rotation.

[0028] Additionally, the viscosity of the grease injected into the bearings may increase due to a drop in temperature while the motor 10 is stopped. Furthermore, if the motor 10 is stopped for an extended period of time, dirt may accumulate and harden inside the motor 10. For these various reasons, the motor 10 may not rotate when restarted after it has stopped rotating.

[0029] In this embodiment, the anomaly detection unit 130 can detect a first-type anomaly while the motor 10 is rotating. That is, deterioration of the motor 10 that could cause a rotation failure is detected before the motor 10 actually fails to rotate. In this case, the display control unit 150 outputs a notification regarding maintenance of the motor 10 to the display device 90.

[0030] The notification output to the display device 90 by the display control unit 150 includes, for example, a warning urging the user to replace or repair the motor 10. This allows the user of the electronic device 40 to take measures such as repairing or replacing the motor 10 before a rotation failure of the motor 10 occurs.

[0031] As described above, during normal operation of electronic device 40, the rotational torque M of motor 10 is controlled to a predetermined torque Ms. If motor 10 does not rotate in this state, a rotation failure of motor 10 has occurred. If deterioration of motor 10 continues to progress, this rotation failure of motor 10 may become apparent. The abnormality detection unit 130 detects a state in which the rotation failure of motor 10 has become apparent as the second type of abnormality of motor 10 described above.

[0032] If the motor 10 fails to rotate properly, the electronic device 40 cannot dissipate heat. Therefore, the power supply control unit 140 turns off the switch 70 to cut off the power supply from the power source 80 to the electronic device 40. This protects the components of the electronic device 40. If measures such as repairing or replacing the motor 10 are taken, the electronic device 40 can continue to be used.

[0033] 2 is a diagram illustrating an example of changes in the rotational state of motor 10 over time T. Fig. 2 illustrates the rotation speed R of motor 10N when normal, the rotation speed R of motor 10P when a first type of abnormality is detected, and the rotation speed R of motor 10E when a second type of abnormality is detected.

[0034] At time zero, motor 10 begins activation. From the start of activation of motor 10 until a predetermined period Tx has elapsed, rotation control unit 110 controls rotation torque M of motor 10 to a low torque Mi that is lower than predetermined torque Ms. From time Tc after the predetermined period Tx has elapsed, rotation control unit 110 controls rotation torque M of motor 10 to predetermined torque Ms. During normal operation of electronic device 40, rotation torque M of motor 10 is controlled to predetermined torque Ms.

[0035] The rotation speed R of a normal motor 10N shown in FIG. 2 increases from zero during a predetermined period Tx until it reaches a rotation value Ri at time Ti. Thereafter, the rotation speed R maintains the rotation value Ri until the predetermined period Tx has elapsed. Therefore, the sensor 60 detects that the motor 10 is rotating. The sensor 60 outputs a sensor signal indicating that the motor 10 is rotating to the rotation state determination unit 120. The rotation state determination unit 120 determines that the motor 10 is rotating.

[0036] 2, the rotation speed R of motor 10P in which a first type of abnormality is detected and motor 10E in which a second type of abnormality is detected remains zero during the predetermined period Tx. Therefore, sensor 60 detects that motor 10 is not rotating. Sensor 60 outputs a sensor signal indicating that motor 10 is not rotating to rotation state determination unit 120. Rotation state determination unit 120 determines that motor 10 is not rotating.

[0037] The rotation speed R of a normal motor 10N shown in FIG. 2 increases from the rotation speed Ri after time Tc after a predetermined period Tx has elapsed until it reaches the rotation speed Rs at time Ts. After that, the rotation speed R maintains the rotation speed Rs. Therefore, the sensor 60 detects that the motor 10 is rotating. The sensor 60 outputs a sensor signal indicating that the motor 10 is rotating to the rotation status determination unit 120. The rotation status determination unit 120 determines that the motor 10 is rotating.

[0038] As shown in FIG. 2, the rotation speed R of motor 10P in which a first type abnormality is detected increases from zero after a predetermined period Tx has elapsed until it reaches rotation value Rs at time Ts. After that, rotation speed R maintains rotation value Rs. Therefore, sensor 60 detects that motor 10 is rotating. Sensor 60 outputs a sensor signal indicating that motor 10 is rotating to rotation state determination unit 120. Rotation state determination unit 120 determines that motor 10 is rotating.

[0039] 2, the rotation speed R of motor 10E in which a second type of abnormality is detected remains at zero after a predetermined period Tx has elapsed. Therefore, sensor 60 detects that motor 10 is not rotating. Sensor 60 outputs a sensor signal indicating that motor 10 is not rotating to rotation state determination unit 120. Rotation state determination unit 120 determines that motor 10 is not rotating.

[0040] The abnormality detection unit 130 detects an abnormality in the motor 10 based on the results of the determination of the rotation state of the motor 10 by the rotation state determination unit 120 during the predetermined period Tx and after the predetermined period Tx has elapsed. Figure 3 is a diagram for explaining abnormality detection based on the rotation state of the motor 10.

[0041] Assume that the motor 10 is rotating while the rotational torque M is controlled to a low torque Mi, and also while the rotational torque M is controlled to a predetermined torque Ms. In other words, if the motor 10 is rotating for a predetermined period Tx and is still rotating after the predetermined period Tx has elapsed, the abnormality detection unit 130 detects that the motor 10 is normal. The motor 10N illustrated in FIG. 2 is detected to be normal in this manner.

[0042] Assume that the motor 10 is not rotating while the rotational torque M is controlled to a low torque Mi, and is rotating while the rotational torque M is controlled to a predetermined torque Ms. In other words, if the motor 10 is not rotating during a predetermined period Tx, and is rotating after the predetermined period Tx has elapsed, the abnormality detection unit 130 detects a first type abnormality in the motor 10.

[0043] In the case of the motor 10P illustrated in Fig. 2, a first type abnormality is detected in this manner. When a first type abnormality is detected, the display control unit 150 outputs a notification regarding maintenance of the motor 10 to the display device 90.

[0044] In the first type abnormality, the motor 10 continues to rotate while the rotational torque M is controlled to the predetermined torque Ms. Because the rotational failure of the motor 10 is latent, the user of the electronic device 40 is unlikely to notice the possibility of deterioration of the motor 10 while the rotational torque M is controlled to the predetermined torque Ms.

[0045] When the motor 10 starts to start after being stopped, it is more difficult for the motor 10 to rotate than when the electronic device 40 is in operation, due to the reasons described above, such as the large friction of the bearings in the motor 10. Furthermore, if the rotational torque M at the start of the motor 10 is controlled to a low torque Mi, the motor 10 becomes even more difficult to rotate.

[0046] Therefore, in addition to the rotational state of the motor 10 in which the rotational torque M is controlled to a predetermined torque Ms, the rotational state of the motor 10 in which the rotational torque M is controlled to a low torque Mi during a predetermined period Tx from the start of startup of the motor 10 is also used to detect an abnormality in the motor 10. This allows a first type abnormality to be detected, making it easier for the user to notice possible deterioration of the motor 10.

[0047] Assume that the motor 10 is not rotating while the rotational torque M is controlled to a low torque Mi, and is also not rotating while the rotational torque M is controlled to a predetermined torque Ms. In other words, if the motor 10 is not rotating during a predetermined period Tx and is still not rotating after the predetermined period Tx has elapsed, the abnormality detection unit 130 detects a second type abnormality of the motor 10.

[0048] In the case of the motor 10E illustrated in Fig. 2, a second type of abnormality is detected in this manner. When a second type of abnormality is detected, the power supply control unit 140 turns off the switch 70, thereby cutting off the power supply from the power supply 80 to the electronic device 40.

[0049] 4 is a flowchart illustrating a processing procedure according to a motor control method according to this embodiment. This processing procedure is performed, for example, by the motor control device 20 included in the electronic device 40. When this processing procedure is started, power is supplied to the electronic device 40, and activation of the motor 10 begins. In step S1, the rotation control unit 110 controls the rotation torque M of the motor 10 to a low torque Mi that is lower than a predetermined torque Ms.

[0050] In step S2, the rotation state determination unit 120 determines the rotation state of the motor 10 based on the sensor signal output from the sensor 60. In step S3, the rotation control unit 110 determines whether a predetermined period Tx has elapsed. If step S3 returns YES, the process proceeds to step S4. If step S3 returns NO, the process repeats step S3.

[0051] In step S4, rotation control unit 110 controls rotation torque M of motor 10 to a predetermined torque Ms. In step S5, rotation state determination unit 120 determines the rotation state of motor 10 based on the sensor signal output from sensor 60. In step S6, abnormality detection unit 130 detects an abnormality in motor 10 based on the rotation state of motor 10 determined in step S2 and the rotation state of motor 10 determined in step S5.

[0052] In step S7, the abnormality detection unit 130 determines whether the motor 10 is normal as a result of the abnormality detection process for the motor 10 in step S6. If the result in step S7 is YES, the motor 10 is detected to be normal, and this processing procedure ends. If the result in step S7 is NO, this processing procedure proceeds to step S21.

[0053] In step S21, the abnormality detection unit 130 determines whether or not a first-class abnormality has been detected in the motor 10 as a result of the abnormality detection process for the motor 10 in step S6. If the result in step S21 is YES, the process proceeds to step S22. If the result in step S21 is NO, the process proceeds to step S41.

[0054] In step S22, the display control unit 150 outputs a notification regarding maintenance of the motor 10 to the display device 90. When the process of step S22 is completed, this processing procedure ends.

[0055] In step S41, the power supply control unit 140 turns off the switch 70 to cut off the power supply from the power source 80 to the electronic device 40. When the process of step S41 is completed, this process procedure ends.

[0056] According to this embodiment, a first type abnormality of the motor 10 is detected based on the rotational state of the motor 10 when the rotational torque M is controlled to a low torque Mi and the rotational state of the motor 10 when the rotational torque M is controlled to a predetermined torque Ms. Therefore, an abnormality in the motor 10 that could cause a rotation failure can be detected before the rotation failure of the motor 10 actually occurs.

[0057] The above embodiment may be modified as follows: In the following modifications, explanations that overlap with the embodiment will be omitted.

[0058] (Variation 1) In the above-described embodiment, the sensor 60 is a lock sensor. However, the sensor 60 is not limited to this. In this variation 1, the sensor 60 is a pulse sensor. The sensor 60 outputs a pulse signal corresponding to the rotation speed R of the motor 10 to the rotation state determination unit 120 as a sensor signal related to the rotation state of the motor 10.

[0059] The rotation state determination unit 120 calculates the rotation speed R of the motor 10 based on the sensor signal. The abnormality detection unit 130 detects an abnormality in the motor 10 based on the rotation speed R of the motor 10 during a predetermined period Tx and the rotation speed R of the motor 10 after the predetermined period Tx has elapsed.

[0060] FIG. 5 is a diagram illustrating an example of changes in the rotational state of motor 10 over time T. The changes in rotational torque M and rotation speed R of motors 10N, 10P, and 10E over time T shown in FIG. 5 are the same as those shown in FIG. 2. Unlike FIG. 2, FIG. 5 also shows a first threshold value R1 and a second threshold value R2 for rotation speed R. The first threshold value R1 and the second threshold value R2 are used by the abnormality detection unit 130 to detect a first-type abnormality and a second-type abnormality, respectively, in motor 10. The detection of first-type abnormality and second-type abnormality will be described later with reference to FIG. 6.

[0061] If the motor 10 is operating normally, it is expected that the rotation speed R will have already reached the rotation value Ri at time Ti within the predetermined period Tx from the start of activation of the motor 10. The rotation value Ri is greater than the first threshold value R1. The rotation state determination unit 120 calculates the rotation speed R of the motor 10 based on the pulse signal at time Ti when the motor 10 is controlled with low torque Mi.

[0062] At time Ti within a predetermined period Tx, the rotation speed R of a normal motor 10N illustrated in Fig. 5 is greater than the first threshold value R1. The rotation speeds R of a motor 10P in which a first type abnormality is detected and a motor 10E in which a second type abnormality is detected, both illustrated in Fig. 5, are smaller than the first threshold value R1.

[0063] If motor 10 is normal, it is expected that rotation speed R will have already reached rotation value Rs at time Ts, which is later than time Tc, which is the predetermined period Tx after motor 10 has started up. Rotation value Rs is greater than second threshold value R2. Rotation state determination unit 120 calculates rotation speed R of motor 10 based on the pulse signal at time Ts, when motor 10 is controlled at predetermined torque Ms.

[0064] At time Ts after the predetermined period Tx has elapsed, the rotation speeds R of the normal motor 10N and the motor 10P in which a first type of abnormality is detected, as shown in Fig. 5, are both greater than the second threshold value R2. The rotation speed R of the motor 10E in which a second type of abnormality is detected, as shown in Fig. 5, is smaller than the second threshold value R2.

[0065] The abnormality detection unit 130 detects an abnormality in the motor 10 based on the calculation results of the rotation speed R of the motor 10 by the rotation state determination unit 120 during the predetermined period Tx and after the predetermined period Tx has elapsed. Fig. 6 is a diagram for explaining abnormality detection based on the rotation speed R of the motor 10.

[0066] Assume that the rotation speed R of the motor 10 exceeds the first threshold value R1 while the rotation torque M is controlled to a low torque Mi, and exceeds the second threshold value R2 while the rotation torque M is controlled to a predetermined torque Ms. That is, if the rotation speed R of the motor 10 during a predetermined period Tx exceeds the first threshold value R1, and if the rotation speed R of the motor 10 after the predetermined period Tx has elapsed exceeds the second threshold value R2, the abnormality detection unit 130 detects that the motor 10 is normal. The motor 10N illustrated in FIG. 5 is detected to be normal in this manner.

[0067] Assume that the rotation speed R of motor 10 does not exceed the first threshold value R1 while the rotation torque M is controlled to a low torque Mi, and exceeds the second threshold value R2 while the rotation torque M is controlled to a predetermined torque Ms. In other words, if the rotation speed R of motor 10 does not exceed the first threshold value R1 during a predetermined period Tx, and if the rotation speed R of motor 10 exceeds the second threshold value R2 after the predetermined period Tx has elapsed, the abnormality detection unit 130 will detect a first type abnormality in motor 10.

[0068] In the case of the motor 10P illustrated in Figure 5, a Type 1 abnormality is detected in this manner. When a Type 1 abnormality is detected, the display control unit 150 outputs a notification regarding maintenance of the motor 10 to the display device 90. This detects a Type 1 abnormality, making it easier for the user to notice the possibility of deterioration of the motor 10. This is expected to lead to measures such as repairing or replacing the motor 10.

[0069] Assume that the rotation speed R of motor 10 does not exceed the first threshold value R1 while the rotation torque M is controlled to the low torque Mi, and does not exceed the second threshold value R2 while the rotation torque M is controlled to the predetermined torque Ms. In other words, if the rotation speed R of motor 10 during a predetermined period Tx does not exceed the first threshold value R1, and if the rotation speed R of motor 10 after the predetermined period Tx has elapsed does not exceed the second threshold value R2, the abnormality detection unit 130 detects a second type abnormality of motor 10.

[0070] In the case of the motor 10E illustrated in Fig. 5, a type 2 abnormality is detected in this manner. When a type 2 abnormality is detected, the power supply control unit 140 turns off the switch 70 to cut off the power supply from the power source 80 to the electronic device 40. This protects the components of the electronic device 40.

[0071] If deterioration of the motor 10 progresses, the rotation speed R of the motor 10 may decrease excessively after the predetermined period Tx has elapsed. If the rotation speed R of the motor 10 decreases excessively, the electronic device 40 may not be able to dissipate heat sufficiently. According to the present modification 1, if the rotation speed R of the motor 10 does not exceed the second threshold value R2 after the predetermined period Tx has elapsed, the power supply from the power source 80 to the electronic device 40 may be cut off. Therefore, the components of the electronic device 40 are protected.

[0072] (Variation 2) In the above-described embodiment, the rotation speed R of motor 10P in which a first type abnormality is detected reaches rotation speed value Rs at time Ts after a predetermined period Tx has elapsed. If deterioration of motor 10P progresses, there is a possibility that rotation speed R will not reach rotation speed value Rs.

[0073] The first type of abnormality of the motor 10 includes a first type of initial abnormality in the early stage when a rotation failure of the motor 10 is latent, and a first type of later abnormality in the later stage after the early stage. In this second modification, the abnormality detection unit 130 distinguishes between the first type of initial abnormality and the first type of later abnormality when detecting the abnormality.

[0074] In this modification 2, the sensor 60 is a pulse sensor, as in modification 1. The rotation state determination unit 120 calculates the rotation speed R of the motor 10 based on the pulse signal, which is a sensor signal, output from the sensor 60. The abnormality detection unit 130 detects an abnormality in the motor 10 based on the rotation speed R of the motor 10 during a predetermined period Tx and the rotation speed R of the motor 10 after the predetermined period Tx has elapsed.

[0075] Fig. 7 is a diagram illustrating an example of changes in the rotational state of motor 10 over time T. The changes in rotational torque M and rotation speed R of motors 10N, 10P, and 10E over time T shown in Fig. 7 are the same as those in the examples shown in Figs. 2 and 5. The first threshold value R1 and second threshold value R2 of rotation speed R shown in Fig. 7 are the same as those in the example shown in Fig. 5.

[0076] 2 and 5, Fig. 7 shows the change in the rotation speed R of the motor 10Pa over time T. Furthermore, Fig. 7 shows a third threshold value R3 for the rotation speed R. The third threshold value R3 is greater than the second threshold value R2. The second threshold value R2 and the third threshold value R3 are used to distinguish between and detect a Type 1 early abnormality and a Type 1 late abnormality.

[0077] A motor 10 in which a Type 1 late abnormality is detected is considered to be in a more deteriorated state than a motor 10 in which a Type 1 early abnormality is detected. Detection of Type 1 early abnormality and Type 1 late abnormality will be described later with reference to FIG. 8.

[0078] At time Ti within predetermined period Tx, the rotation speed R of normal motor 10N illustrated in Fig. 7 is greater than first threshold value R1. The rotation speeds R of motors 10P and 10Pa in which a first type abnormality is detected, and motor 10E in which a second type abnormality is detected, are all smaller than first threshold value R1.

[0079] If the motor 10 is normal, it is expected that the rotation speed R will have already reached the rotation value Rs at time Ts after the predetermined period Tx has elapsed. The rotation value Rs is greater than the third threshold value R3.

[0080] The following three cases can be assumed as cases in which the motor 10 is abnormal. In the first case, the rotation speed R exceeds the third threshold value R3 at time Ts. In the second case, the rotation speed R exceeds the second threshold value R2 but does not exceed the third threshold value R3. In the third case, the rotation speed R does not exceed the second threshold value R2.

[0081] As shown in FIG. 7 , among motors 10P and 10Pa for which a first type abnormality is detected, the rotation speed R of motor 10P reaches rotation value Rs at time Ts. That is, the rotation speed R of motor 10P is greater than the third threshold value R3. This corresponds to the first case described above. The rotation speed R of motor 10Pa reaches rotation value Rsa at time Ts. That is, the rotation speed R of motor 10Pa exceeds the second threshold value R2 but does not exceed the third threshold value R3. This corresponds to the second case described above.

[0082] 7, the rotation speed R of the motor 10E when the second type abnormality is detected remains zero at time Ts. That is, the rotation speed R of the motor 10E does not exceed the second threshold value R2. This corresponds to the third case described above.

[0083] The abnormality detection unit 130 detects an abnormality in the motor 10 based on the calculation results of the rotation speed R of the motor 10 by the rotation state determination unit 120 during the predetermined period Tx and after the predetermined period Tx has elapsed. Fig. 8 is a diagram for explaining abnormality detection based on the rotation speed R of the motor 10.

[0084] Assume that the rotation speed R of the motor 10 exceeds the first threshold value R1 while the rotation torque M is controlled to a low torque Mi, and exceeds the third threshold value R3 while the rotation torque M is controlled to a predetermined torque Ms. That is, if the rotation speed R of the motor 10 during a predetermined period Tx exceeds the first threshold value R1, and if the rotation speed R of the motor 10 after the predetermined period Tx has elapsed exceeds the third threshold value R3, the abnormality detection unit 130 detects that the motor 10 is normal. The motor 10N illustrated in FIG. 7 is detected to be normal in this manner.

[0085] Assume that the rotation speed R of motor 10 does not exceed the first threshold value R1 while the rotation torque M is controlled to the low torque Mi, and exceeds the third threshold value R3 while the rotation torque M is controlled to the predetermined torque Ms. In other words, if the rotation speed R of motor 10 does not exceed the first threshold value R1 during the predetermined period Tx, and if the rotation speed R of motor 10 exceeds the third threshold value R3 after the predetermined period Tx has elapsed (first case), the abnormality detection unit 130 detects a first type initial abnormality of motor 10.

[0086] In the case of the motor 10P illustrated in Figure 7, a Type 1 initial abnormality is detected in this manner. When a Type 1 initial abnormality is detected, the display control unit 150 outputs a notification regarding maintenance of the motor 10 to the display device 90. This detects a Type 1 initial abnormality, making it easier for the user to realize that the motor 10 may be in the early stages of deterioration. This is expected to lead to measures such as repairing or replacing the motor 10.

[0087] While the rotational torque M is controlled to a low torque Mi, the rotational speed R of the motor 10 does not exceed a first threshold value R1. Thereafter, while the rotational torque M is controlled to a predetermined torque Ms, the rotational speed R of the motor 10 exceeds a second threshold value R2 but does not exceed a third threshold value R3. If deterioration of the motor 10 progresses, the rotational speed R of the motor 10 may decrease, preventing it from exceeding the third threshold value R3.

[0088] That is, the rotation speed R of the motor 10 during the predetermined period Tx does not exceed the first threshold value R1. After the predetermined period Tx has elapsed, the rotation speed R of the motor 10 exceeds the second threshold value R2 but does not exceed the third threshold value R3 (second case). In this case, the abnormality detection unit 130 detects a first type late abnormality of the motor 10.

[0089] In the case of motor 10Pa shown in Figure 7, a Type 1 late abnormality is detected in this manner. When a Type 1 late abnormality is detected, display control unit 150 outputs a notification regarding maintenance of motor 10 to display device 90. This detects a Type 1 late abnormality, making it easier for the user to realize that motor 10 may be in a later stage of advanced deterioration. Therefore, it is expected that measures such as repair or replacement of motor 10 will be taken promptly.

[0090] Assume that the rotation speed R of motor 10 does not exceed the first threshold value R1 while the rotation torque M is controlled to the low torque Mi, and does not exceed the second threshold value R2 while the rotation torque M is controlled to the predetermined torque Ms. In other words, if the rotation speed R of motor 10 during the predetermined period Tx does not exceed the first threshold value R1, and if the rotation speed R of motor 10 after the predetermined period Tx has elapsed does not exceed the second threshold value R2 (third case), the abnormality detection unit 130 detects a second type abnormality of motor 10.

[0091] In the case of the motor 10E illustrated in Fig. 7, a type 2 abnormality is detected in this manner. When a type 2 abnormality is detected, the power supply control unit 140 turns off the switch 70 to cut off the power supply from the power source 80 to the electronic device 40. This protects the components of the electronic device 40.

[0092] According to the second modification, the first type of abnormality of the motor 10 is detected as a first type early abnormality or a first type late abnormality, depending on the degree of deterioration of the motor 10. Therefore, the user of the electronic device 40 can determine the priority of taking measures such as repairing or replacing the motor 10, depending on the degree of deterioration of the motor 10.

[0093] The following additional notes are provided regarding the above-described embodiment and modifications.

[0094] (Supplementary Note 1) The present disclosure provides a motor control device (20) that controls a motor (10), comprising: a rotation control unit (110) that controls a rotational torque (M) of the motor to a predetermined torque (Ms) to rotate the motor, and controls the rotational torque to a low torque (Mi) that is lower than the predetermined torque until a predetermined period (Tx) has elapsed since activation of the motor begins; and an abnormality detection unit (130) that detects an abnormality in the motor based on the rotational state of the motor in which the rotational torque has been controlled to the low torque and the rotational state of the motor in which the rotational torque has been controlled to the predetermined torque.

[0095] (Supplementary Note 2) In the motor control device described in Supplementary Note 1, the abnormality of the motor detected by the abnormality detection unit includes a first type abnormality in which a rotation failure of the motor is latent, and a second type abnormality in which the rotation failure of the motor is apparent, and the motor control device may further include a display control unit (150) that outputs a notification regarding maintenance of the motor to a display device (90) when the first type abnormality is detected by the abnormality detection unit.

[0096] (Supplementary Note 3) In the motor control device described in Supplementary Note 2, the motor may be provided in a fan motor of an electronic device (40), and the motor control device may further include a power supply control unit (140) that cuts off the power supply from a power source (80) to the electronic device when the second type abnormality is detected by the abnormality detection unit.

[0097] (Supplementary Note 4) In the motor control device described in Supplementary Note 3, if the motor has not rotated during the specified period and is rotating after the specified period has elapsed, the abnormality detection unit may detect the first type of abnormality, and if the motor has not rotated during the specified period and is not rotating after the specified period has elapsed, the abnormality detection unit may detect the second type of abnormality.

[0098] (Supplementary Note 5) In the motor control device described in Supplementary Note 3, the abnormality detection unit may detect the abnormality of the motor based on the number of rotations (R) of the motor during the predetermined period and the number of rotations after the predetermined period has elapsed.

[0099] (Supplementary Note 6) In the motor control device described in Supplementary Note 5, if the rotation speed during the specified period does not exceed a first threshold value (R1) and the rotation speed after the specified period has elapsed exceeds a second threshold value (R2), the abnormality detection unit may detect the first type of abnormality, and if the rotation speed during the specified period does not exceed the first threshold value and the rotation speed after the specified period has elapsed does not exceed the second threshold value, the abnormality detection unit may detect the second type of abnormality.

[0100] (Appendix 7) In the motor control device described in Appendix 6, the first type abnormality includes a first type initial abnormality in an early stage when the rotation failure of the motor is latent, and a first type later abnormality in a later stage after the initial stage, and the abnormality detection unit may detect the first type initial abnormality if the rotation speed after the specified period of time exceeds a third threshold value (R3) that is greater than the second threshold value, and may detect the first type later abnormality if the rotation speed after the specified period of time exceeds the second threshold value but does not exceed the third threshold value.

[0101] (Appendix 8) The motor control method of the present disclosure is a motor control method for controlling a motor, and includes a rotation control step of controlling the rotational torque of the motor to a predetermined torque to rotate the motor, and controlling the rotational torque to a low torque lower than the predetermined torque until a predetermined period of time has elapsed since startup of the motor begins, and an abnormality detection step of detecting an abnormality in the motor based on the rotational state of the motor with the rotational torque controlled to the low torque and the rotational state of the motor with the rotational torque controlled to the predetermined torque.

[0102] (Appendix 9) In the motor control method described in Appendix 8, the abnormality of the motor detected in the abnormality detection step includes a first type abnormality in which a rotation failure of the motor is latent, and a second type abnormality in which the rotation failure of the motor is apparent, and the motor control method may further include a display control step of outputting a notification regarding maintenance of the motor to a display device when the first type abnormality is detected in the abnormality detection step.

[0103] (Supplementary Note 10) In the motor control method described in Supplementary Note 9, the motor may be provided in a fan motor of an electronic device, and the motor control method may further include a power supply control step of cutting off power supply from a power source to the electronic device when the second type abnormality is detected in the abnormality detection step.

[0104] (Supplementary Note 11) In the motor control method described in Supplementary Note 10, if the motor has not rotated during the predetermined period and is rotating after the predetermined period has elapsed, the first type of abnormality may be detected in the abnormality detection step, and if the motor has not rotated during the predetermined period and is not rotating after the predetermined period has elapsed, the second type of abnormality may be detected in the abnormality detection step.

[0105] (Supplementary Note 12) In the motor control method described in Supplementary Note 10, the abnormality detection step may detect the abnormality of the motor based on the number of rotations of the motor during the predetermined period and the number of rotations after the predetermined period has elapsed.

[0106] (Appendix 13) In the motor control method described in Appendix 12, if the rotation speed during the specified period does not exceed a first threshold value and the rotation speed after the specified period has elapsed exceeds a second threshold value, the first type of abnormality may be detected in the abnormality detection step, and if the rotation speed during the specified period does not exceed the first threshold value and the rotation speed after the specified period has elapsed does not exceed the second threshold value, the second type of abnormality may be detected in the abnormality detection step.

[0107] (Appendix 14) In the motor control method described in Appendix 13, the first type abnormality may include a first type initial abnormality in an early stage when the rotation failure of the motor is latent, and a first type later abnormality in a later stage after the initial stage, and if the rotation speed after the predetermined period has elapsed exceeds a third threshold value that is greater than the second threshold value, the abnormality detection step may detect the first type initial abnormality, and if the rotation speed after the predetermined period has elapsed exceeds the second threshold value but does not exceed the third threshold value, the abnormality detection step may detect the first type later abnormality.

[0108] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0109] REFERENCE SIGNS LIST 10... motor 20... motor control device 40... electronic device 50... storage device 60... sensor 70... switch 80... power supply 90... display device 110... rotation control unit 120... rotation state determination unit 130... abnormality detection unit 140... power supply control unit 150... display control unit

Claims

1. A motor control device for controlling a motor, comprising: a rotation control unit that controls the rotational torque of the motor to a predetermined torque to rotate the motor, and controls the rotational torque to a low torque lower than the predetermined torque until a predetermined period elapses after the start of the motor startup; and an abnormality detection unit that detects an abnormality of the motor based on the rotational state of the motor when the rotational torque is controlled to the low torque and the rotational state of the motor when the rotational torque is controlled to the predetermined torque.

2. The motor control device according to claim 1, wherein the abnormality of the motor detected by the abnormality detection unit includes a first type of abnormality in which a rotation failure of the motor is latent, and a second type of abnormality in which the rotation failure of the motor is manifest, and the motor control device further includes a display control unit that outputs a notification regarding maintenance of the motor to a display device when the first type of abnormality is detected by the abnormality detection unit.

3. The motor control device according to claim 2, wherein the motor is provided in a fan motor of an electronic device, and the motor control device further includes a power supply control unit that cuts off power supply from the power source to the electronic device when the second type of abnormality is detected by the abnormality detection unit.

4. The motor control device according to claim 3, wherein when the motor does not rotate during the predetermined period and the motor rotates after the predetermined period has elapsed, the abnormality detection unit detects the first type of abnormality, and when the motor does not rotate during the predetermined period and the motor does not rotate after the predetermined period has elapsed, the abnormality detection unit detects the second type of abnormality.

5. The motor control device according to claim 3, wherein the abnormality detection unit detects the abnormality of the motor based on the number of rotations of the motor during the predetermined period and the number of rotations after the predetermined period has elapsed.

6. The motor control device according to claim 5, wherein when the rotational speed during the predetermined period does not exceed a first threshold value and the rotational speed after the elapse of the predetermined period exceeds a second threshold value, the abnormality detection unit detects the first type of abnormality; and when the rotational speed during the predetermined period does not exceed the first threshold value and the rotational speed after the elapse of the predetermined period does not exceed the second threshold value, the abnormality detection unit detects the second type of abnormality.

7. The motor control device according to claim 6, wherein the first type of abnormality includes a first type of initial abnormality at an initial stage where the rotation failure of the motor is latent and a first type of late-stage abnormality at a late stage after the initial stage; when the rotational speed after the elapse of the predetermined period exceeds a third threshold value greater than the second threshold value, the abnormality detection unit detects the first type of initial abnormality; and when the rotational speed after the elapse of the predetermined period exceeds the second threshold value and does not exceed the third threshold value, the abnormality detection unit detects the first type of late-stage abnormality.

8. A motor control method for controlling a motor, comprising: a rotation control step of controlling the rotational torque of the motor to a predetermined torque to rotate the motor, and controlling the rotational torque to a low torque lower than the predetermined torque until a predetermined period elapses after the start of the motor startup; and an abnormality detection step of detecting an abnormality of the motor based on the rotational state of the motor when the rotational torque is controlled to the low torque and the rotational state of the motor when the rotational torque is controlled to the predetermined torque.

9. The motor control method according to claim 8, wherein the abnormality of the motor detected in the abnormality detection step includes a first type of abnormality in which the rotation failure of the motor is latent and a second type of abnormality in which the rotation failure of the motor is manifest; and the motor control method further includes a display control step of outputting a notification regarding maintenance of the motor to a display device when the first type of abnormality is detected in the abnormality detection step.

10. The motor control method according to claim 9, wherein the motor is provided in a fan motor of an electronic device, and the motor control method further comprises a power supply control step of cutting off power supply from the power supply to the electronic device when the second type of abnormality is detected in the abnormality detection step.

11. The motor control method according to claim 10, wherein when the motor has not rotated during the predetermined period and the motor rotates after the predetermined period has elapsed, the first type of abnormality is detected in the abnormality detection step; and when the motor has not rotated during the predetermined period and the motor has not rotated after the predetermined period has elapsed, the second type of abnormality is detected in the abnormality detection step.

12. The motor control method according to claim 10, wherein in the abnormality detection step, the abnormality of the motor is detected based on the rotation speed of the motor during the predetermined period and the rotation speed after the predetermined period has elapsed.

13. The motor control method according to claim 12, wherein when the rotation speed during the predetermined period does not exceed a first threshold value and the rotation speed after the predetermined period has elapsed exceeds a second threshold value, the first type of abnormality is detected in the abnormality detection step; and when the rotation speed during the predetermined period does not exceed the first threshold value and the rotation speed after the predetermined period has elapsed does not exceed the second threshold value, the second type of abnormality is detected in the abnormality detection step.

14. The motor control method according to claim 13, wherein the first type of abnormality includes a first type of initial abnormality at an initial stage where the rotation failure of the motor is latent and a first type of late-stage abnormality at a late stage after the initial stage has passed. When the rotation speed after the predetermined period has elapsed exceeds a third threshold value greater than the second threshold value, the first type of initial abnormality is detected in the abnormality detection step; and when the rotation speed after the predetermined period has elapsed exceeds the second threshold value and does not exceed the third threshold value, the first type of late-stage abnormality is detected in the abnormality detection step.

Images