JP6312645B2 - Motor driving apparatus capable of reporting abnormal operation of fan and method thereof - Google Patents

Description

  The present invention relates to a motor drive device capable of notifying a user of an abnormal operation of a fan, and a method thereof.

  An apparatus capable of detecting an abnormality in the rotational speed of a fan is known (for example, Patent Document 1).

JP-A-10-28394

  In a motor drive device that drives a servo motor built in a machine tool or industrial robot, a control scheme that stops operation of the motor drive device when a fan abnormality is detected may be used.

  In this case, the detection of the fan abnormality immediately leads to the stop of the work process. Therefore, in the field of motor drive devices, it is required to detect signs of fan abnormality at an early stage from the viewpoint of improving work efficiency.

  In one aspect of the present invention, the motor drive device includes a fan, a fan control unit that controls the fan, a rotation number detection unit that detects the rotation number of the fan, and a point from when the fan control unit changes the rotation number. A relationship acquisition unit that acquires a relationship between the time and the rotation number detected by the rotation number detection unit;

  In addition, the motor drive device determines that the relationship is different from the reference by the abnormality determination unit that determines whether or not the relationship acquired by the relationship acquisition unit is different from a predetermined reference. In this case, an abnormality signal generation unit that generates a signal indicating that an abnormality has occurred in the fan is provided.

  The relationship acquisition unit, as a relationship, of the number of rotations detected by the rotation number detection unit in a period until a predetermined time elapses from the time when the fan control unit transmits a command for changing the number of rotations to the fan. The amount of change may be acquired. The abnormality determination unit may determine that the relationship is different from the reference when the calculated change amount is larger or smaller than a predetermined threshold.

  The relationship acquisition unit, as a relationship, of the number of rotations detected by the rotation number detection unit in a period until a predetermined time elapses from the time when the fan control unit transmits a command for changing the number of rotations to the fan. A ratio of the change amount to the reference may be calculated. The abnormality determination unit may determine that the relationship is different from the reference when the ratio is larger or smaller than a predetermined threshold.

  The relationship acquisition unit detects the rotation speed when the fan control unit transmits a command to the fan to change the rotation speed from the first rotation speed to a second rotation speed different from the first rotation speed. You may acquire the time until the rotation speed which the part detected turns from the 1st rotation speed to the 2nd rotation speed.

  The abnormality determination unit may determine that the relationship is different from the reference when the calculated time is larger or smaller than a predetermined threshold. The motor drive device may further include a time measuring unit that measures a time from a point in time when the fan control unit changes the rotation speed.

  The motor drive device may further include a storage unit that stores the number of rotations detected by the rotation number detection unit or the time from the time when the fan control unit changes the number of rotations. The motor drive device may further include an alarm output unit that receives the signal and outputs a warning to the user.

  In another aspect of the present invention, a method for notifying a user of an abnormal operation of a fan provided in a motor drive device includes: changing the rotation speed of the fan; and changing the rotation speed when the rotation speed is being changed. Detecting.

  Also, this method acquires the relationship between the time from when the rotation speed is changed and the detected rotation speed, and determines whether the acquired relationship is different from a predetermined reference. And notifying the user that an abnormality has occurred in the fan when it is determined that the relationship is different from the reference.

It is a perspective view of the motor drive device concerning one embodiment of the present invention. It is a block diagram of the motor drive device shown in FIG. It is a front view of the fan shown in FIG. It is a graph showing the relationship between this rotation speed and time when the rotation speed of a fan is decelerated. It is a graph showing the relationship between this rotation speed and time when the rotation speed of a fan is accelerated. It is a flowchart which shows one Example of the operation | movement flow of the motor drive apparatus shown in FIG. It is a flowchart which shows the other Example of the operation | movement flow of the motor drive apparatus shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, with reference to FIGS. 1-3, the motor drive device 10 which concerns on one Embodiment of this invention is demonstrated. The motor drive device 10 supplies electric power to the servo motor in order to drive a servo motor (not shown) built in a machine tool or an industrial robot.

  As shown in FIG. 1, the motor driving device 10 includes a housing 12. The housing 12 is a box-shaped member made of, for example, a resin, and accommodates components such as a control unit 16 described later therein. A through hole 14 is formed in the housing 12.

  As shown in FIG. 2, the motor drive device 10 further includes a control unit 16, a fan 18, a rotation speed detection unit 19, an alarm output unit 20, a time measuring unit 22, and a storage unit 24. The control unit 16 includes, for example, a CPU and is accommodated in the housing 12. The control unit 16 directly or indirectly controls each component of the motor drive device 10.

  The fan 18 is accommodated in the housing 12 so as to face the through hole 14 formed in the housing 12. As shown in FIG. 3, the fan 18 includes a rotating body 28 including a plurality of blades 26 and a fan motor 30 that rotates the rotating body 28.

  The rotating body 28 is disposed adjacent to the through hole 14 formed in the housing 12. The fan motor 30 is connected to an inverter 32 (FIG. 2). The inverter 32 supplies power to the fan motor 30 in response to a command from the control unit 16.

  The fan motor 30 rotationally drives the rotating body 28 at a rotational speed corresponding to the electric power supplied from the inverter 32. When the rotating body 28 is driven to rotate, the gas in the housing 12 is discharged to the outside through the through hole 14, thereby cooling the motor driving device 10.

  The rotation speed detection unit 19 includes, for example, an encoder or a hall element, and is attached to the fan 18. The rotational speed detection unit 19 detects the rotational speed of the rotating body 28 of the fan 18 in accordance with a command from the control unit 16, and transmits data relating to the detected rotational speed of the fan 18 to the control unit 16.

  The alarm output unit 20 includes, for example, a speaker or a display unit, and outputs a sound wave or an image in response to a command from the control unit 16. In response to a command from the control unit 16, the time measuring unit 22 measures an elapsed time from a certain time point.

  The storage unit 24 includes an electrically erasable / recordable non-volatile memory such as an EEPROM (registered trademark), or a random access memory such as a DRAM or SRAM that can be read and written at high speed. . The control unit 16 can store data in the storage unit 24 and erase data from the storage unit.

  As the fan 18 is operated, foreign matter such as dust or cutting fluid may adhere to the rotating body 28 of the fan 18, thereby impeding the rotation of the rotating body 28. The motor drive device 10 according to the present embodiment detects such an abnormality of the fan 18.

Hereinafter, the concept of abnormality detection of the fan 18 in the motor drive device 10 will be described with reference to FIGS. 4 and 5. 4, the control unit 16 transmits the rotation speed change command to the fan motor 30 at time t _1, when decelerating the rotational speed of the fan 18 from the rotational speed R ₂ to the rotation speed R _1, the fan 18 It is a graph which shows the relationship between the rotation speed R and time t.

On the other hand, FIG. 5, when the control unit 16 transmits the rotation speed change command to the fan motor 30 at time t _4, it accelerated the rotational speed of the fan 18 from the rotational speed R ₄ to the rotational speed R _5, fan It is a graph which shows the relationship between the rotation speed R of 18 and time t.

  A solid line 34 in FIG. 4 and a solid line 38 in FIG. 5 indicate characteristics when the fan 18 is operating normally (hereinafter referred to as a normal product). On the other hand, a broken line 36 in FIG. 4 and a broken line 40 in FIG. 5 indicate that a foreign object has adhered to the rotating body 28 of the fan 18 and an abnormality has occurred in the operation of the fan 18 (hereinafter referred to as an abnormal product). ) Characteristics.

Referring to FIG. 4, when obtained by reducing the rotational speed R, in the normal product, the rotational speed R decreases from the time t ₁ relatively gently, has reached the rotational speed R ₁ at time t _3. On the other hand, in the abnormal product, the rotational speed R decreases from the time point t _{1 with} a steeper slope than the characteristics of the normal product, and reaches the rotational speed R ₁ at the time point t ₂ (<t ₃ ). ing.

Thus, the relationship between the rotational speed R of the time t ₁ after the time t and the normal products and (t-R relationship) between the t-R relationship time t ₁ after the abnormal products, significant difference Occurs. This is because the rotation of the abnormal rotating body 28 is hindered by the adhesion of foreign matter.

  The motor drive device 10 according to the present embodiment detects an abnormal operation of the fan 18 using the difference in the tR relationship between the normal product and the abnormal product. The tR relationship of the fan 18 can be evaluated by various parameters described below.

As an example, in FIG. 4, the amount of change δR _ref of the rotational speed R of a normal product during a period t _1-2 (= t ₂ −t ₁ ) from time t ₁ to time t ₂ is δR _ref ≈R ₂ − the R _3. On the other hand, in the period _{t 1-2,} variation &Dgr; R of the rotational speed R of the abnormal product, the δR ≒ _R 2 -R _1. Here, it is clear from FIG. 4 that the variation δR of the abnormal product is significantly larger than the variation δR _ref of the normal product.

Therefore, if the above-mentioned δR is acquired as a parameter representing the t-R relationship of the fan 18, and the δR _{ref of} a normal product is used as a reference and compared with each other, an abnormal operation of the fan 18 in use can be detected.

As another example, a parameter representing a t-R relationship fan 18, the ratio R = δR / δR _ref ≒ variation &Dgr; R relative to the reference _{δR ref (R 2 -R 1)} / (R 2 -R 3) , And the ratio R is compared with a predetermined threshold value, whereby an abnormal operation of the fan 18 in use can be detected.

As another example, in a normal product, a period t _1-3 (= t ₃ -t ₁ ) is required until the rotational speed R changes from R ₂ to R ₁ . in abnormal products, until the rotational speed R becomes the _{R 2} to _{R 1,} it takes time _{t 1-2 (= t 2 -t 1} ). Here, the period t _1-2 abnormal products, can become significantly smaller than the period t _1-3 of the normal product, it is evident from FIG.

Therefore, if the period _t1-2 is acquired as a parameter representing the t-R relationship of the fan 18 and compared with the normal period _t1-3 as a reference, the fan in use 18 operational abnormalities can be detected.

Further, yet another example, as a parameter representing the t-R relationship in use the fan 18, the inclination of the rotational speed R in the above period _{t 1-2} (i.e., _{acceleration): δR / δt = (R} 2 - R ₁ ) / t _1-2 is obtained, and the normal product slope: δR _ref / δt = (R ₂ −R ₃ ) / t _1-2 is used as a reference, and these are compared with each other. Abnormal operation of the fan 18 can be detected.

On the other hand, referring to FIG. 5, when accelerating the rotational speed R, in the normal product, the rotational speed R is increased at a relatively steep slope from the time t _4, the rotational speed R ₅ at time t ₅ Has reached. In contrast, in the abnormal products, the rotational speed R from the time point t _4, and gradually increases than the characteristic of the normal product, at time t _6, has reached the rotational speed R _5.

Thus, even when accelerating the rotational speed R, and t-R relationship normal product of the time t ₄ later, between the t-R relationship abnormal products, the significant difference is produced, thus An abnormal operation of the fan 18 to be inspected can be detected using the difference in the t-R relationship between the normal product and the abnormal product.

As an example, in FIG. 5, the amount of change δR _ref of the rotational speed R of a normal product during a period t _4-5 (= t ₅ −t ₄ ) from time t ₄ to time t ₅ is δR _ref = R ₅ − the R _4. On the other hand, the variation δR of the rotational speed R of the abnormal product in the period t _4-5 is δR = R ₆ −R ₄ . Here, it is clear from FIG. 5 that the variation δR of the abnormal product is significantly smaller than the variation δR _ref of the normal product.

Therefore, if the δR is acquired as a parameter representing the t-R relationship of the fan 18 in use and is compared with the δR _{ref of} a normal product as a reference, an abnormal operation of the fan 18 in use can be detected. it can.

As another example, as a parameter representing the t-R relationship of the fan 18 in use, the ratio of the variation δR to the reference δR _ref R = δR / δR _ref = (R ₆ −R ₄ ) / (R ₅ − By calculating R ₄ ) and comparing the ratio R with a predetermined threshold value, an abnormal operation of the fan 18 in use can be detected.

As another example, referring to FIG. 5, in a normal product, a period t _4-5 (= t ₅ −t ₄ ) is required until the rotational speed R changes from R ₄ to R _5. In contrast, an abnormal product requires a period t _4-6 (= t ₆ −t ₄ ) until the rotational speed R changes from R ₄ to R ₅ . Here, it is clear from FIG. 5 that the period t _4-6 of the abnormal product is significantly longer than the period t _{4-5 of the} normal product.

Therefore, if the period t _4-6 is acquired as a parameter representing the t-R relationship of the fan 18 in use, and the period t _4-5 of a normal product is used as a reference, and these are compared with each other, An abnormal operation of the fan 18 inside can be detected.

As still another example, as a parameter representing the t-R relationship of the fan 18 in use, the slope δR / δt = (R ₆ −R ₄ ) / t ₄ of the rotational speed R in the period t _4-5 . _-5 is obtained and the normal product inclination δR _ref / δt = (R ₅ −R ₄ ) / t _4-5 is used as a reference, and these are compared with each other to detect an abnormal operation of the fan 18 in use. it can.

As described above, the motor drive device 10 according to the present embodiment includes the various parameters (δR, t _1-2 , δR / δt, t _4-6 ) and the reference (δR _ref, t _1-3, δR). _ref / δt, t _4-5 ) to detect whether or not an abnormality has occurred in the operation of the fan 18.

  Next, an example of the operation flow of the motor drive device 10 will be described with reference to FIG. The flow shown in FIG. 6 starts when the control unit 16 receives an abnormality inspection command for inspecting an operation abnormality of the fan 18 from a user, a host controller, or a control program.

  As an example, the control unit 16 performs an abnormality check when accelerating the rotation speed from zero to the normal rotation speed in order to normally operate the fan 18 (that is, when power supply from the inverter 32 to the fan motor 30 is started). Accept the command.

  As another example, the controller 16 decelerates the rotational speed from the normal rotational speed to zero in order to stop the fan 18 that is normally operated (that is, power supply from the inverter 32 to the fan motor 30). When the operation is stopped), an abnormality inspection command is accepted.

  As yet another example, the control unit 16 accepts an abnormality inspection command when the operation is interrupted while the fan 18 is operating normally. The normal rotation speed described above is set in advance as a required value for normal operation of the fan 18.

In step S <b> 1, the control unit 16 changes the rotation speed of the fan 18. As an example, as shown in FIG. 4, the control unit 16 changes the rotational speed R of the fan 18 operating at the rotational speed R ₂ (for example, the normal rotational speed) from the rotational speed R ₂ to the rotational speed R ₁ (for example, zero). In order to decelerate the speed, a rotation speed change command is transmitted to the inverter 32.

As another example, as shown in FIG. 5, the control unit 16 changes the rotational speed R of the fan 18 in the state of the rotational speed R ₄ (for example, zero) from the rotational speed R ₄ to the rotational speed R ₅ (for example, normal). A rotation speed change command is transmitted to the inverter 32 in order to accelerate the rotation speed).

The inverter 32 controls the electric power supplied to the fan motor 30 so that the rotational speed R of the fan 18 is the rotational speed (R ₁ or R ₅ ) corresponding to the rotational speed change command received from the control unit 16. Thus, in the present embodiment, the control unit 16 has a function as the fan control unit 42 (FIG. 2) that controls the operation of the fan 18.

In step S _<b > 2, the control unit 16 acquires the rotational speed _Rx of the fan 18. Specifically, the control unit 16 sends a command to the rotation number detection unit 19 and detects the rotation number _Rx of the rotating body 28 of the fan 18 at this time. The control unit 16 receives data relating to the rotational speed R _x from the rotational speed detection unit 19 and stores the data in the storage unit 24.

As an example, if the rotational speed R decelerating from _{R 2} to _{R 1} at step S1 (FIG. 4), the rotational speed _{R x may} have been measured in step S2, the rotational speed R of the time _{t 1} in FIG. 4 Is approximately equal to ₂ .

As another example, when the rotational speed R is accelerated from R ₄ to R ₅ in step S1 (FIG. 5), the rotational speed R _x measured in step S2 is the time t _{4 in} FIG. will be substantially matched to the rotational speed R _4.

  In step S3, the control unit 16 starts measuring elapsed time. Specifically, the control unit 16 transmits to the time measurement unit 22 a time measurement start command for starting time measurement of the elapsed time. The timer unit 22 measures the elapsed time t from the time when the timing start command is received from the control unit 16.

In step S <b> 4, the control unit 16 acquires the rotational speed _Ry of the fan 18 when the elapsed time t measured by the time measuring unit 22 reaches a predetermined time. The predetermined time is stored in the storage unit 24.

As an example, if the rotational speed R decelerating from R ₂ to R ₁ at step S1 (FIG. 4), this predetermined time is set to the time period t _1-2. As another example, when the rotational speed R is accelerated from R ₄ to R ₅ in step S1 (FIG. 5), this predetermined time is set to the above-described period t _4-5 .

In step S4, the control unit 16 determines in advance from the time (for example, time t _{1 in} FIG. 4 or time t _{4 in} FIG. 5) at which the rotation speed change command is transmitted to the fan 18 in step S1. When the predetermined time (for example, the period _t1-2 or the period _t4-5 ) has elapsed, a command is sent to the rotational speed detection unit 19 in the same manner as in step S2 described above, and the rotational speed of the fan 18 at this time point Get _Ry .

In step S5, the control unit 16 acquires the relationship between the time t and the rotation speed R (t-R relationship). As an example, the control unit 16 uses the amount of change δR _xy = | R _x − from the rotational speed R _x acquired in step S2 to the rotational speed R _y acquired in step S5 as a parameter representing the tR relationship. R _y | (corresponding to the above δR) is calculated.

As another example, the control unit 16 calculates the ratio R = δR _xy / δR _ref as a parameter representing the tR relationship. As still another example, the control unit 16 uses the slope δR / δt (for example, (R ₂ −R ₁ ) / t _1-2 or (R ₆ −R) described above as a parameter representing the tR relationship. ₄ ) / t _4-5 )).

Thus, in the present embodiment, the control unit 16 determines the time t (t _1-2 or t _4-5 ) from the time t ₁ when the rotation speed R of the fan 18 is changed, and the rotation of the fan 18. It has a function as the relationship acquisition part 44 (FIG. 2) which acquires the relationship with the number R (t-R relationship).

In step S6, the control unit 16 determines whether or not the tR relationship acquired in step S5 is different from a predetermined reference. As an example, when the change amount δR _xy = | R _x −R _y | is calculated in step S5, the control unit 16 calculates the change amount δR _xy and the threshold value α ₁ set with respect to the reference δR _ref . Compare.

For example, when the rotational speed R is decelerated from R ₂ to R ₁ in step S1 (FIG. 4), the control unit 16 determines that the change amount δR _xy is a threshold value α ₁ (for example, α ₁ = δR _ref × 1.1). It is determined whether it is larger than.

On the other hand, for example, when the rotational speed R is accelerated from R ₄ to R _{5 in} step S1 (FIG. 5), the control unit 16 determines that the change amount δR _xy is a threshold value α ₁ (for example, α ₁ = δR _ref × 0.9) or less.

When the change amount δR _xy is larger (or smaller) than the threshold α ₁ , the control unit 16 determines that the t-R relationship of the fan 18 is different from the reference δR _ref (that is, YES).

As another example, when calculating the ratio R at step S5, the control unit 16 compares the said ratio R, and a threshold value alpha ₂ set in advance on the ratio R.

For example, when the rotational speed R is decelerated from R ₂ to R ₁ in step S1 (FIG. 4), the control unit 16 determines that the ratio R is larger than a threshold value α ₂ (for example, α ₂ = 1.1). Determine whether or not. On the other hand, when the rotational speed R is accelerated from R ₄ to R ₅ in step S1 (FIG. 5), the control unit 16 determines whether the ratio R is smaller than a threshold value α ₂ (for example, α ₂ = 0.9). Determine whether or not.

When the ratio R is larger (or smaller) than the threshold value α ₂ , the control unit 16 determines that the tR relationship of the fan 18 is different from the reference δR _ref (that is, YES).

As another example, when the slope δR / δt is calculated in step S5, the control unit 16 sets the absolute value of the slope | δR / δt | and the threshold value α set for the reference δR _ref / δt. ₃ is compared.

For example, when the rotational speed R is decelerated from R ₂ to R ₁ in step S ₁ (FIG. 4), the control unit 16 determines that the absolute value | δR / δt | of the slope is a threshold value α ₃ (for example, α ₃ = It is determined whether or not | δR _ref /δt|×1.1).

On the other hand, when the rotational speed R is accelerated from R ₂ to R ₁ in step S1 (FIG. 5), the control unit 16 determines that the absolute value of the inclination (| δR / δt |) is a threshold value α ₃ (for example, , Α ₃ = | δR _ref /δt|×0.9).

Control unit 16, the absolute value of the slope | δR / δt | is larger than the threshold value alpha ₃ (or lower) case, t-R relationship fan 18 (&Dgr; R / .DELTA.t) is different from the reference δR _ref / δt ( That is, it is determined YES). Note that the above-described threshold values α ₁ , α ₂ , or α ₃ are stored in the storage unit 24 in advance.

  If the control unit 16 determines YES in step S6, the control unit 16 proceeds to step S7. On the other hand, if the control unit 16 determines that the tR relationship is not different from the reference (that is, NO), the control unit 16 ends the flow illustrated in FIG.

  Thus, in this embodiment, the control part 16 has a function as the abnormality determination part 46 (FIG. 2) which determines whether the tR relationship of the fan 18 differs from a reference | standard.

  In step S <b> 7, the control unit 16 generates an abnormality notification signal indicating that an abnormality has occurred in the operation of the fan 18. As an example, the control part 16 produces | generates an abnormality alerting signal with the form of the audio | voice signal of the warning sound emitted with respect to a user.

  As another example, the control unit 16 generates an abnormality notification signal in the form of an image signal of a warning image that can be visually recognized by the user. Thus, in this embodiment, the control part 16 has a function as the abnormality signal generation part 48 (FIG. 2) which produces | generates an abnormality notification signal.

  In step S <b> 8, the control unit 16 notifies the user that an abnormality has occurred in the operation of the fan 18 via the alarm output unit 20. As an example, when the sound signal of the warning sound is generated in step S <b> 7, the control unit 16 transmits the sound signal to the alarm output unit 20. In this case, the alarm output unit 20 includes a speaker and outputs the received audio signal as a warning sound.

  As another example, when an image signal of a warning image is generated in step S <b> 7, the control unit 16 transmits the image signal to the alarm output unit 20. In this case, the alarm output unit 20 includes a display unit, and displays a warning image corresponding to the received image signal on the display unit.

  In this way, the user can recognize from the warning sound or warning image that an abnormality has occurred in the operation of the fan 18. As a result, the user can recognize that it is necessary to perform a maintenance operation to remove the foreign matter attached to the rotating body 28 of the fan 18.

  As described above, in the present embodiment, the relationship between the rotational speed R and the time t when the rotational speed R of the fan 18 is changed (that is, the degree of change of the rotational speed R with time). In comparison with the relationship of the standard normal product, it is determined whether or not the rotational speed R of the fan 18 is equivalent to that of the normal product.

  According to this configuration, since the abnormality in the rotational speed R of the fan 18 can be detected with higher accuracy, the abnormality of the fan 18 is erroneously detected, and thereby the operation of the motor driving device 10 is erroneously stopped. Can be surely prevented. Therefore, working efficiency can be improved.

  Next, another embodiment of the operation flow of the motor drive device 10 will be described with reference to FIG. In the operation flow shown in FIG. 7, the same steps as those in the flow shown in FIG. 6 are denoted by the same step numbers, and detailed description thereof is omitted.

  After step S1, in step S11, the control unit 16 starts measuring the rotational speed R of the fan 18. Specifically, the control unit 16 sends a command to the rotation number detection unit 19 to detect the rotation number R of the rotating body 28 of the fan 18 with a period τ (for example, 0.5 seconds). The control unit 16 receives the data related to the rotational speed R from the rotational speed detection unit 19 at the period τ and stores it in the storage unit 24.

In step S12, the control unit 16, the rotational speed R of fan 18 detected in step S11 is to determine whether it has reached the target value R _t predetermined.

As an example, if the rotational speed R decelerating from _{R 2} to _{R 1} at step S1 (FIG. 4), the target value _{R t} is set to the rotation speed _{R 1.} As another example, when the rotational speed R is accelerated from R ₄ to R ₅ in step S1 (FIG. 5), the target value R _t is set to the rotational speed R ₅ .

Control unit 16, when the rotation speed R detected by the step S11 is determined to have reached the target value _{R t} (i.e. YES), the process proceeds to step S13. On the other hand, when it is determined that the rotation speed R has not reached the target value _Rt (that is, NO), the control unit 16 loops step S12.

  In step S13, the control unit 16 functions as the relationship acquisition unit 44 (FIG. 2), and acquires the relationship between the time t and the rotation speed R (t-R relationship). Specifically, the control unit 16 acquires the elapsed time t that the time measuring unit 22 has measured at the time point determined as YES in step S12 as a parameter representing the tR relationship, and stores the elapsed time t in the storage unit 24. To do.

For example, when the rotational speed R is decelerated from R ₂ to R ₁ in step S1 (FIG. 4), the elapsed time t counted at this point is transmitted by the control unit 16 in step S1. This corresponds to a period (t _1-2 ) from the time point (t ₁ ) to the time point (t ₂ ) when the rotational speed R reaches R ₁ .

Further, for example, when the rotational speed R is accelerated from R ₄ to R _{5 in} step S1 (FIG. 5), the elapsed time t counted at this point is determined by the control unit 16 in step S1 to issue a rotational speed change command. This corresponds to a period (t _4-6 ) from the transmission time (t ₄ ) to the time (t ₆ ) when the rotation speed R reaches R ₅ .

  In step S14, the control unit 16 functions as the abnormality determination unit 46 (FIG. 2) and determines whether or not the t-R relationship acquired in step S13 is different from a predetermined reference.

As an example, if the rotational speed R decelerating from _{R 2} to _{R 1} at step S1 (FIG. 4), the control unit 16, the elapsed time t acquired in step S13 (period _{t 1-2)} are described above It is determined whether or not it is smaller than a threshold value α ₄ (for example, α ₄ = t _1-3 × 0.9) set with respect to the reference (period t _1-3 ).

As another example, when the rotational speed R is accelerated from R ₄ to R ₅ in step S1 (FIG. 5), the control unit 16 passes the elapsed time t (period t _4-6 ) acquired in step S13. Is larger than a threshold value α ₄ (for example, α ₄ = t _4-5 × 1.1) set with respect to the above-described reference (period t _4-5 ). The threshold value alpha ₄ is previously stored in the storage unit 24.

When the elapsed time t is larger (or smaller) than the threshold value α ₄ , the controller 16 has a t-R relationship of the fan 18 that is different from the reference (period t _1-3 or period t _4-5 ) (ie, the period t _4-5 ). YES).

  If the control unit 16 determines YES, the control unit 16 proceeds to step S7. On the other hand, when determining that the tR relationship is not different from the reference (that is, NO), the control unit 16 ends the flow shown in FIG.

  As described above, according to the operation flow according to FIG. 7, the abnormality in the rotational speed R of the fan 18 can be detected with higher accuracy as in the flow illustrated in FIG. 6. For this reason, it is possible to reliably prevent the abnormality of the fan 18 from being erroneously detected and thereby the operation of the motor drive device 10 being erroneously stopped. Therefore, working efficiency can be improved.

  It should be noted that at least one of the timekeeping unit 22 and the storage unit 24 described above may be incorporated in the control unit 16 or in an external device (for example, a server) that is communicably connected to the control unit 16 via a network. It may be incorporated into.

  As mentioned above, although this invention was demonstrated through embodiment of invention, the above-mentioned embodiment does not limit the invention based on a claim. In addition, a combination of the features described in the embodiments of the present invention can also be included in the technical scope of the present invention, but all of these combinations of features are essential to the solution of the invention. Not exclusively. Furthermore, it will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments.

  Further, the execution order of each process such as operation, procedure, step, process, and stage in the apparatus, system, program, and method shown in the claims, the specification, and the drawings is particularly “before”. It should be noted that it may be implemented in any order unless it is explicitly stated as “prior to” or the like, and the output of the previous process is not used in the subsequent process. Even if the operation flow in the claims, the description, and the drawings is described using “first,” “next,” “next,” etc. for the sake of convenience, it is essential to implement them in this order. It doesn't mean that.

DESCRIPTION OF SYMBOLS 10 Motor drive device 16 Control part 18 Fan 19 Rotation number detection part

Claims (11)

With fans,
A fan control unit for controlling the fan;
Said first and when the fan control unit has changed the number of revolutions of the fan, at a second time when the predetermined time from the time the first has elapsed, for detecting the rotational speed of the fan A rotational speed detector;
Using the first rotation speed detected at the first time point and the second rotation speed detected at the second time point, the time from the first time point and the rotation speed A relationship acquisition unit that acquires a relationship with the rotation speed detected by the detection unit;
An abnormality determination unit that determines whether or not the relationship acquired by the relationship acquisition unit is different from a predetermined reference;
A motor drive device comprising: an abnormality signal generation unit configured to generate a signal indicating that an abnormality has occurred in the fan when the abnormality determination unit determines that the relationship is different from the reference. The fan control unit transmits a command for changing the rotation speed of the fan to the fan at the first time point,
2. The motor drive device according to claim 1, wherein the relationship includes a change amount between the first rotation speed and the second rotation speed in a period from the first time point to the second time point. . The relationship acquisition unit acquires the amount of change as the relationship,
The motor drive device according to claim 2 , wherein the abnormality determination unit determines that the relationship is different from the reference when the acquired change amount is larger or smaller than a predetermined threshold. The relationship acquisition unit, as the relationship, to calculate the ratio for the previous SL reference of the amount of change,
The motor drive device according to claim 2 , wherein the abnormality determination unit determines that the relationship is different from the reference when the ratio is larger or smaller than a predetermined threshold. The relationship acquisition unit calculates , as the relationship, a slope of change in the rotation speed with respect to time, obtained by dividing the change amount by the period ,
The motor drive device according to claim 1, wherein the abnormality determination unit determines that the relationship is different from the reference when the calculated inclination is larger or smaller than a predetermined threshold. The motor driving device according to claim 1, wherein the fan control unit decelerates the rotational speed of the fan at the first time point. The motor driving device according to claim 6, wherein the fan control unit stops power supply to the fan at the first time point. Wherein said further comprising first counting unit for measuring an elapsed time from the time, the motor driving apparatus according to any one of claims 1-7. The motor drive device according to any one of claims 1 to 8 , further comprising a storage unit that stores the rotation number detected by the rotation number detection unit or an elapsed time from the first time point. To receive the signal, further comprising an alarm output unit for outputting a warning to the user, the motor driving apparatus according to any one of claims 1-9. A method of notifying a user of an abnormal operation of a fan provided in a motor drive device,
Changing the rotational speed of the fan;
Detecting the rotational speed at a first time point when the rotational speed of the fan is changed and a second time point when a predetermined time has elapsed from the first time point ;
Using the first rotation speed detected at the first time point and the second rotation speed detected at the second time point, the time from the first time point and the detected Obtaining the relationship with the rotational speed,
Determining whether the acquired relationship is different from a predetermined criterion;
And notifying the user that an abnormality has occurred in the fan when it is determined that the relationship is different from the reference.

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