JP2000092894A - Monitor of hysteresis motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sensitivities of the abnormality sensings of hysteresis motors, by absorbing the variations of the current values of the current vectors corresponding to respective driving currents fed to the respective hysteresis motors, and by making small by the absorbed portion a threshold used for the abnormality sensings. SOLUTION: In this monitor, the current-value components of the current vectors outputted from respective current transformers 2 are converted by respective conversion circuits 4 to normalize the current vectors of respective hysteresis motors. Then, the current values of the respective current vectors are made to coincide with the current value of their average current-vector. When a larger difference than a preset threshold is generated between one of these respective current values and the average current value, the hysteresis motor corresponding to the current vector having the larger difference than the preset threshold is determined that it has been brought into an abnormal state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hysteresis motor monitoring device for monitoring the operating state of a hysteresis motor.

[0002]

2. Description of the Related Art A hysteresis motor (HM) for generating a rotating magnetic field and rotating a rotor having a permanent magnet embedded therein.
Are connected to each other to drive the load, and a hysteresis motor monitoring device is used to monitor whether each hysteresis motor is operating normally.

[0003] The hysteresis motor monitoring device includes a plurality of current transformers that output a current detection signal corresponding to the magnitude of the effective current and the magnitude of the reactive current obtained by transforming the drive current supplied to each hysteresis motor. Averaging the current detection signals (current vectors) output from the respective current transformers to obtain an average current vector, and comparing the average current vector with each current vector to determine whether there is a hysteresis motor abnormally stopped. And a determination circuit for determining whether or not the determination is made. And in this hysteresis motor monitoring device,
Average each current vector to obtain an average current vector,
The difference between the average current vector and the current vector of the drive current supplied to each hysteresis motor is calculated. As shown in FIG. 4, when a difference larger than a preset threshold value is detected, it is determined that the hysteresis motor corresponding to the difference is abnormal and has stopped.

[0004]

When a system using such a hysteresis motor is manufactured, a variation of ± a% (a is a certain value) occurs with respect to a design value, and a current value is increased. Since the power factor varies, it is necessary to determine a threshold value for judging whether it is normal or abnormal so that even if the power factors deviate to the maximum, it is not judged to be abnormal.

At this time, as a general tendency, the absolute value of the variation of the current value becomes larger than the absolute value of the variation of the power factor, so that in the conventional hysteresis motor monitoring device, the variation of the current value is large. As a result, the magnitude of the threshold is determined.

Therefore, when detecting whether there is a hysteresis motor which is abnormally stopped, as shown in FIG.
If the difference between the current value of the current vector of the hysteresis motor that is operating normally and the current value of the current vector of the hysteresis motor that is abnormally stopped is small and the variation of the current vector of each hysteresis motor is large, Even if any one of the motors becomes abnormal, there is a problem that the variation range of the current vector of the abnormal hysteresis motor falls within the threshold range of the average current vector, which cannot be detected. .

When a hysteresis motor having a rated rotation speed bHz (b is a certain value) is operated with "slip", as shown in FIG. 6, the "slip" of the current vector of the synchronous escape characteristic is obtained. "To" 0 Hz "and the current vector of the hysteresis motor that is abnormally stopped to" slip ".
Assuming “bHz”, the current vector of the hysteresis motor can be expressed as a linear approximation between “0 Hz” and “bHz”.

However, when the characteristics of each hysteresis motor vary and the threshold value used at the time of abnormality detection is set to be large, even if any of the hysteresis motors becomes abnormal during operation, this Until the hysteresis motor is almost stopped, there is a problem that the abnormality of the hysteresis motor cannot be detected.

In view of the above circumstances, according to the present invention, the current vectors of the individual hysteresis motors are normalized so as to match the average current vector, thereby absorbing the variation of the current vector, and by that amount, the abnormality is corrected. An object of the present invention is to provide a hysteresis motor monitoring device capable of reducing the threshold value used for detection and increasing the sensitivity of abnormality detection.

According to a second aspect of the present invention, each of the hysteresis motors is adjusted to match the average current vector at a time when all the hysteresis motors are known to be operating normally (when both the hysteresis motor and the load are new). By setting the conversion coefficient necessary to normalize the current vector in advance, the variation of the current vector is absorbed, and the threshold value used for abnormality detection is reduced by that much. It is an object of the present invention to provide a hysteresis motor monitoring device capable of increasing the sensitivity of the motor.

According to a third aspect of the present invention, the current value components constituting the current vectors of the respective hysteresis motors are normalized so as to match the current value of the average current vector, thereby absorbing the current component of the variation of the current vector. Only that much
It is an object of the present invention to provide a hysteresis motor monitoring device capable of reducing the threshold value used for abnormality detection and increasing the sensitivity of abnormality detection.

[0012]

To achieve the above object, according to the present invention, there is provided a hysteresis motor monitoring device for monitoring whether or not a plurality of hysteresis motors are operating normally. A vector synthesis circuit that averages the motor current vector to generate an average current vector, a conversion circuit that normalizes the current vector of each hysteresis motor based on a preset conversion coefficient, and a vector synthesis circuit that is output from the vector synthesis circuit. The average current vector and the normalized current vector output from the conversion circuit are compared, and each hysteresis motor is determined based on whether or not the difference is out of a preset threshold range. And a comparison circuit for determining whether or not the abnormality has occurred.

According to a second aspect of the present invention, in the hysteresis motor monitoring apparatus according to the first aspect, the conversion circuit is configured to perform a predetermined timing so that a difference between a current vector and an average current vector of each hysteresis motor is minimized. The value of each conversion coefficient corresponding to each hysteresis motor is adjusted, and the comparison circuit sets a small threshold value according to the current vector normalized by the conversion circuit.

According to a third aspect of the present invention, in the hysteresis motor monitoring device according to any one of the first and second aspects, the conversion circuit is configured to perform the conversion based on each conversion coefficient set in advance.
It is characterized in that the current components constituting the current vector of each hysteresis motor are normalized.

According to the first aspect of the present invention, in the first aspect, the current vector of each hysteresis motor is averaged by the vector synthesizing circuit to generate an average current vector. While normalizing the current vectors of the respective hysteresis motors, the comparison circuit compares the average current vector output from the vector synthesis circuit with each of the normalized current vectors output from the conversion circuit. By judging whether or not each hysteresis motor is abnormal based on whether or not it is out of the set threshold range, the current vector of each hysteresis motor is adjusted so as to match the average current vector. Is normalized to absorb the variation of the current vector, and the abnormality is detected To reduce the threshold to be used,
Increase the sensitivity of abnormality detection.

According to the present invention, the value of each conversion coefficient corresponding to each hysteresis motor is adjusted at a predetermined timing so that the difference between the current vector of each hysteresis motor and the average current vector is minimized. By setting a small threshold value according to the current vector normalized by the circuit, the average is obtained when all the hysteresis motors are known to be operating normally (both when the hysteresis motor and the load are new). Set the conversion coefficient necessary to normalize the current vector of each hysteresis motor in advance so that it matches the current vector, absorb the variation of the current vector, and use that much the threshold value used for abnormality detection To increase the sensitivity of abnormality detection.

According to a third aspect of the present invention, the current components constituting the current vectors of the respective hysteresis motors are normalized by the conversion circuit based on the preset conversion coefficients so as to match the current value of the average current vector. In addition, the current value components that make up the current vector of each hysteresis motor are normalized, the current component of the current vector variation is absorbed, and the threshold value used for abnormality detection is reduced by that much, and the abnormality detection is performed. To increase the sensitivity.

[0018]

FIG. 1 is a block diagram showing an embodiment of a hysteresis motor monitoring apparatus according to the present invention.

The hysteresis motor monitoring device 1 shown in FIG. 1 transforms the drive current supplied to each hysteresis motor, and outputs a current detection signal corresponding to the power factor and the current value of the drive current supplied to each hysteresis motor. A plurality of current transformers 2 that output current vectors, a vector synthesis circuit 3 that averages each current detection signal output from each current transformer 2 to generate an average current vector, and a conversion that is set in advance. A plurality of conversion circuits for converting a current component of the current detection signal output from each current transformer based on the coefficient to generate a normalized current vector; and an average current vector output from the vector synthesis circuit 3 When each current vector output from each conversion circuit 4 does not fall within a range of a preset threshold value, a plurality of comparison circuits for generating an alarm signal are generated. And a 5.

When all the hysteresis motors and the loads driven by the respective hysteresis motors are in a new state and the respective hysteresis motors are operating, the current of the average current vector output from the vector combining circuit 3 is calculated. The operator adjusts the conversion coefficient of each conversion circuit 4 so that the value matches the current value of the current vector output from each conversion circuit 4 and, as shown in FIG. Each comparison circuit 5 according to
Is set small.

In this way, when any one of the hysteresis motors becomes abnormal during the operation of each hysteresis motor and the current vector deviates from the range of the threshold value centering on the average current vector, the abnormality occurs. This is detected by the comparison circuit 5 corresponding to the changed hysteresis motor, and an alarm signal is generated.

At this time, as shown in FIG.
Since the threshold value set for the hysteresis motor is small, the comparator circuit 5 corresponding to the hysteresis motor detects this at the time when the abnormal hysteresis motor starts slipping (at the time when the motor comes out of synchronization), and the hysteresis motor is activated. An alarm signal indicating that an abnormality has occurred is output.

As described above, in this embodiment, each conversion circuit 4 converts the current value component of the current vector output from each conversion circuit 2 to normalize the current vector of each hysteresis motor, and Since the current value of the current vector and the current value of the average current vector are matched, the variation of the current component of the current vector is absorbed, and the threshold value used for abnormality detection is reduced by that much, and the abnormal The detection sensitivity can be increased (the effect of claim 1).

Also, in this embodiment, a time when all the hysteresis motors are known to be operating normally (a time when both the hysteresis motor and the load are new)
In addition, since the conversion coefficient of each conversion circuit 4 is adjusted so that the current value of each current vector corresponding to each hysteresis motor matches the current value of the average current vector, each hysteresis motor, each hysteresis motor Even if there are variations in the characteristics of the load driven by the current transformers 2 and the like, the variations in the current components of the current vectors output from the respective current transformers 2 are absorbed, and the variation is used for abnormality detection. The sensitivity of abnormality detection can be increased by reducing the threshold value (the effect of claim 2).

Further, in this embodiment, the current value components constituting the current vector of each hysteresis motor are normalized so as to match the current value of the average current vector, thereby absorbing the variation of the current component of the current vector. As compared with the case where the power factor of each current vector is normalized, the configuration of each conversion circuit 4 is simplified, the threshold value used for abnormality detection is reduced, and the sensitivity of abnormality detection is improved. It can be increased (the effect of claim 3).

[0026]

As described above, according to the present invention, in the hysteresis motor monitoring device according to the first aspect, the current vectors of the individual hysteresis motors are normalized so as to match the average current vector, and the variation of the current vector is obtained. Can be absorbed, and the threshold value used for abnormality detection can be reduced by that much, and the sensitivity of abnormality detection can be increased.

In the hysteresis motor monitoring device according to the second aspect of the present invention, when the hysteresis motors are known to be operating normally (when both the hysteresis motor and the load are new), the individual hysteresis motors are adjusted to match the average current vector. By setting the conversion coefficient necessary to normalize the current vector of the hysteresis motor in advance, the variation of the current vector is absorbed, and
By reducing the threshold value used for abnormality detection, the sensitivity of abnormality detection can be increased.

In the hysteresis motor monitoring device according to the third aspect, the current value components constituting the current vectors of the individual hysteresis motors are normalized so as to match the current value of the average current vector, and the current component of the variation of the current vector is reduced. Absorption is achieved, and the threshold value used for abnormality detection is reduced by that much, so that the sensitivity of abnormality detection can be increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a hysteresis motor monitoring device according to the present invention.

FIG. 2 is a schematic diagram showing a relationship between a threshold value of the hysteresis motor monitoring device shown in FIG. 1 and a current vector of a hysteresis motor that is abnormally stopped.

FIG. 3 is a schematic diagram showing a relationship between a threshold value of the hysteresis motor monitoring device shown in FIG. 1 and a current vector from the occurrence of an abnormality in the hysteresis motor to the stop thereof.

FIG. 4 is a schematic diagram showing an example of a current vector when a general hysteresis motor is operating normally, and an example of a current vector when it is abnormally stopped.

FIG. 5 is a schematic diagram illustrating a relationship between a threshold value of a conventionally known hysteresis motor monitoring device and a current vector of a hysteresis motor that is abnormally stopped.

FIG. 6 is a schematic diagram showing a relationship between a threshold value of a conventionally known hysteresis motor monitoring device and a current vector from the occurrence of an abnormality in the hysteresis motor to the stop thereof.

[Explanation of symbols]

 1: Hysteresis motor monitoring device 2: Current transformer 3: Vector synthesis circuit 4: Conversion circuit 5: Comparison circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G016 BA04 BD01 BD07 BD09 5G044 AA01 AB05 AE01 AE03 5H572 BB07 BB10 CC01 DD05 EE03 GG07 HB07 HC01 HC07 LL22 LL26 MM09 5H576 BB06 BB10 CC01 DD06 GG07 HB01 LL22 LL22 MM22

Claims (3)

[Claims] 1. A hysteresis motor monitoring device for monitoring whether or not a plurality of hysteresis motors are operating normally, a vector synthesis circuit for averaging current vectors of the respective hysteresis motors and generating an average current vector; A conversion circuit that normalizes the current vector of each hysteresis motor based on the conversion coefficient that has been set, and an average current vector output from the vector synthesis circuit and each normalized current vector output from the conversion circuit. And a comparison circuit for determining whether or not each hysteresis motor is abnormal based on whether or not these differences are out of a preset threshold range. Hysteresis motor monitoring device. 2. The hysteresis motor monitoring device according to claim 1, wherein the conversion circuit is configured to control each hysteresis motor at a predetermined timing such that a difference between a current vector and an average current vector of each hysteresis motor is minimized. The hysteresis motor monitoring device is characterized in that the value of each conversion coefficient corresponding to the following is adjusted, and the comparison circuit sets a small threshold value according to the current vector normalized by the conversion circuit. 3. The hysteresis motor monitoring device according to claim 1, wherein the conversion circuit calculates a current component forming a current vector of each hysteresis motor based on each conversion coefficient set in advance. A hysteresis motor monitoring device characterized by normalizing.