JP2007236032A - Ripple detector and number of revolution detector of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ripple detector of a motor in which decision precision of ripple can be enhanced without increasing the data region in a storage medium of a means for storing judgment data, and to provide a number of revolution detector. <P>SOLUTION: The ripple detector 1 of a motor comprises a means 2 for storing peak data at three points becoming decision data of ripple, a means 3 for detecting the driving current of the motor, a means 4 for extracting the peak data of a current detected by the detection means 3, and a comparison/decision means 5 for deciding whether the peak data at three continuous points of the current is ripple or not wherein the comparison/judgment means 5 compares the peak data at three points stored in the storage means 2 with the peak data at three continuous points of the current extracted by the extraction means 4 and decides that the peak data at three continuous points of the current as ripple. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor ripple detection device and a rotation speed detection device suitable for application to a DC motor having a brush.

  Usually, when detecting the rotation speed of a DC motor with a brush, a speed detection sensor such as an encoder or a pulse generator is required, and a separate speed detection sensor is provided, leading to an increase in cost. There is also a method of detecting the rotational speed by utilizing the fact that the back electromotive force of the DC motor is proportional to the rotational speed, but this detects the exact rotational speed when the resistance changes due to the temperature change of the DC motor. Can not do it.

Therefore, by detecting the ripple (pulsation) included in the current of the DC motor and counting the number of ripples as a means for detecting the accurate rotation speed without using a speed detection sensor and changing the resistance, A system for detecting the rotational speed is described in Patent Document 1. This is because the frequency of the ripple contained in the current of the DC motor is the number of rotations and the number of commutator pieces (segments) provided in the rotor that are in contact with the brush and supply current to the rotor. It is used for the in-vehicle system, such as a memory seat system, power window device, sunroof device, etc., and the amount of movement of each moving part is detected based on the detected number of rotations for control. We are using.
JP 2004-80921 A

  However, in such a system or apparatus, determination data as to whether or not it is ripple is stored in advance, and if the difference in the actually detected current period with respect to the period of the determination data is within a predetermined threshold value If the current is judged to be rippled and detected, the load on the DC motor is not always constant and the operating environment of the DC motor (eg temperature, brush wear, applied voltage current, etc.) is in operation. Therefore, the period of the determination data stored as a database in the storage medium in advance for detecting the ripple may be greatly different from the period of the current, and the ripple and the current to be detected cannot be detected as the ripple.

  In order to cope with this, it is necessary to increase a predetermined threshold (period) used for detecting the ripple. However, as shown in FIG. 14, when the current is distorted by noise, it is determined as one ripple. However, there is a possibility that the detection location is determined and detected as two ripples, and the ripple detection accuracy is lowered.

  In addition, the database of judgment data must have both currents that should be judged as ripples, such as ripples when the waveform is distorted by noise, and currents that should not be judged as ripples. Since there are a wide variety of types, it is necessary to increase the data area of the storage medium of the storage means used for storing the determination data.

  Alternatively, it is possible to determine the ripple only from the trend of the current change. In this case, however, it is difficult to distinguish the current change caused by load fluctuations or changes in the operating environment from the current change distorted by noise. The accuracy of detection may decrease.

  Also, as shown in FIG. 15, when the noise in the frequency band ½ of the frequency of the ripple is large, as shown in FIG. It is necessary to compare waveforms, and in this case, it is necessary to increase the threshold used for comparison. In this case, as shown in FIG. 17, when the current is distorted by the influence of noise, a distorted current waveform is generated. All are determined as ripples, and there is a possibility that erroneous determinations of ripples, that is, erroneous detections, increase.

  Accordingly, in view of the above problems, the present invention eliminates the need to increase the data area of the storage medium of the storage means for storing the determination data, and can improve the ripple determination accuracy of the motor and the number of revolutions of the motor. The main object is to provide a detection device, or to provide a ripple detection device and a rotation number detection device for a motor that can detect an erroneous determination of a ripple and thereby correct the number of ripples.

In order to solve the above problem, a motor ripple detection device according to the present invention is:
Storage means for storing peak data at three points, which are judgment data as to whether or not it is ripple, detection means for detecting the current for driving the motor, and extraction for extracting the peak data of the current detected by the detection means And a comparison / determination unit that determines whether or not the peak data of the three consecutive points of the current are ripples, and the comparison / determination unit stores the three-point peak data stored in the storage unit and the The peak data at three consecutive points of current extracted by the extracting means are compared, and the peak data at three consecutive points of current are determined as ripples.

  Ripple here refers to the pulsation that occurs in the current that drives the motor as the motor rotates in a DC motor having brushes and commutator pieces. The number of ripples depends on the number of commutator pieces and the number of revolutions. Proportional. The peak data indicates the maximum value or the minimum value of the current for driving the motor and its time.

  The comparison determination means compares the three points of peak data stored by the storage means with the three points of continuous peak current of the current extracted by the extraction means, and the three points of current When it is determined that the peak data of the current is not a ripple, if the two points of peak data following the three points of continuous peak data of the current satisfy a predetermined condition, the extraction means uses the peak data of the two points to The peak data of the three points are replaced by replacing the peak data of the two most recent points among the peak data of the three points, and the comparison judgment unit stores the updated three points of peak data in the storage unit. Compared with the peak data of the three points that are the determination data, it is determined whether the ripple is present.

  Here, the predetermined condition is that when the comparison determination unit determines that the peak data of the three consecutive points of the current are not ripples, and the peak data of the following two points are maximum values, the comparison target If the peak data is larger than the peak data to be compared, and if it is a minimum value, the case is smaller than the peak data to be compared.

  In addition, in order to make the determination data as data in the load fluctuation or operating environment as close as possible to the peak data of the three points to be compared, the peak data of the three consecutive points of the current extracted by the extracting means are ripples When the comparison / determination unit determines that the current is, the three-point peak data serving as the determination data stored in the storage unit is preferably updated with the peak data of the three consecutive points of the current. Here, if the maximum value of the peak data at the three consecutive points of the current is excessive and the minimum value is excessive, the peak data at the three points is considered to be sudden data and used as judgment data. Do not update because it is not appropriate to do.

  Furthermore, since the current for driving the actual motor fluctuates due to load fluctuations and changes in the operating environment, the comparison / determination means stores the peak data (current value and time) of three current points in the storage means. Rather than comparing the peak data itself, it is necessary to obtain the amplitude or both of the amplitude and period as follows when comparing the peak data itself to determine whether it is ripple or not. It is preferable to compare.

  That is, the comparison / determination unit obtains the amplitude of the ripple determined by the determination data from the three points of peak data stored in the storage unit, and the current is detected from the peak data of the three points of current detected by the detection unit. It is preferable to determine whether the peak data at three consecutive points of the current are ripples by comparing the amplitudes of the currents.

  Alternatively, the comparison / determination unit obtains a ripple period and amplitude determined by the determination data from the three points of peak data stored in the storage unit, and from the peak data of three points of current detected by the detection unit. The period and amplitude of the current may be obtained, and it may be determined whether the peak data at three consecutive points of the current are ripples by comparing the period and amplitude.

  The solution described above is suitable for application when the peak data at three points can be compared as adjacent ripples immediately before the peak data at three points of continuous current. However, as described above, in determining whether the detected current is a ripple, it may be preferable to compare the detected current with the previous ripple instead of the adjacent ripple. In this case, as described above, it is necessary to increase the threshold value (threshold value) used for the comparison, so that an erroneous determination of ripple may occur.

  In such a case, in order to detect an erroneous determination of ripple, it is preferable to take the following method.

  That is, when the comparison / determination means classifies the ripple determined to be the ripple by comparing the rising amplitude and the falling amplitude of the ripple, and when the combination of consecutive ripple classes is a predetermined combination, the erroneous determination of the ripple Is detected. Here, the classification means that the ripples are classified according to the shape of each ripple.

  As described above, the method of classifying the ripples and detecting the erroneous determination of the ripples can be applied to a method of detecting the ripples by comparing the current waveforms themselves as in the prior art.

In other words, the motor ripple detection device applied in this case includes a storage means for storing a ripple waveform of a current serving as determination data, a detection means for detecting a current for driving the motor, and a current detected by the detection means. Extraction means for extracting a current waveform within a predetermined period of time, and comparison determination means for determining whether or not the extracted current waveform is ripple, and the comparison determination means is stored by the storage means Comparing the ripple waveform with the current waveform extracted by the extraction means, a ripple detection device for a motor that determines that the current waveform is ripple,
The comparison / determination means classifies the ripples by comparing the rising and falling amplitudes of the ripples, and detects an erroneous determination of ripples when the combination of consecutive ripple classes is a predetermined combination. To do.

  The motor rotation speed detection device according to the present invention has a counting means for counting the ripples determined to be ripples by the motor ripple detection device as described above, and the number of ripples counted by the counting means. From the above, the number of rotations of the motor is detected.

  According to the present invention, it is possible to provide a motor ripple detection device or rotation speed detection device that can increase the accuracy of ripple determination without increasing the data area of the storage medium of the storage means for storing the determination data. can do. Alternatively, according to the present invention, there is also provided a motor ripple detection device capable of detecting an erroneous determination of ripple, and a motor rotation number detection device capable of correcting the rotation number by correcting the ripple count. be able to.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing an embodiment of a motor rotation speed detection device according to the present invention.

The motor rotation speed detection device 1 according to the present embodiment includes a storage means 2 for storing three-point peak data serving as data for determining whether or not there is a ripple, and detection for detecting A / D conversion of the motor current. Means 3, extraction means 4 for extracting peak data at three consecutive points of current detected by the detection means 2, and comparison determination means 5 for determining whether the peak data at three consecutive points of the current are ripples. The comparing / determining means 5 compares the peak data of the three points stored by the storage means 2 with the peak data of the three consecutive points of the current extracted by the extracting means 3, and determines the continuous peak data of the current. And counting means 6 that counts the peak data of three points as ripples when it is determined that it is ripple, and the motor from the number of ripples counted by the counting means 6 And detecting the number of revolutions. (Excluding the counting means 6 is a motor ripple detection apparatus according to the present invention.)
According to this, since the ripple and the motor current that are the basis of the determination data can be compared and determined as three continuous peak data, it can be accurately performed without increasing the capacity of the storage medium of the storage means 2. Ripple can be determined.

  In FIG. 1, reference numeral 7 denotes a motor, and 8 denotes motor control means. The motor control means 8 controls the voltage / current of the motor 7 based on the rotational speed detected by the rotational speed detection device 1 of the motor.

  Here, when the comparison determination unit 5 determines that the peak data at three consecutive points of current extracted by the extraction unit 5 is a ripple, the peak data at the three consecutive points of current is stored in the storage unit 2. The three points of peak data that are the judgment data are updated.

  As a result, the peak data at three points, which are judgment data for determining whether or not there are ripples, can be used as the latest load fluctuations or data in the operating environment as much as possible with respect to the peak data at three consecutive points of the extracted current. In addition, the detection accuracy of the ripple and thus the detection accuracy of the rotation speed of the motor can be increased.

  The motor rotation speed detection device 1 may be configured by a computer having a well-known CPU, ROM, RAM, a bus line for interconnecting these, and an appropriate interface, or may be an ASIC.

  Here, the control content of the motor rotation speed detection device shown in FIG. 1 is shown. FIG. 2 is a flowchart showing the control contents of the motor rotation speed detection device according to the present invention.

  In S1, the extracting means 4 extracts the rising peak of the current that drives the motor 7. In S2, the extracting means 4 extracts the falling peak. In S3, the extracting means 4 extracts the rising peak. In S4 and S5, The initial value of each peak data is not judged to be updated, the amplitude of the current is calculated from each peak data in S6, and compared with the amplitude of the judgment data stored in the storage means 2 in S7. Determine whether the current is ripple.

  If it is determined that the current is a ripple, the storage unit 2 registers the peak data of three consecutive points of the current as a ripple and outputs a ripple determination signal in S8, and the count unit 6 determines the ripple. The number of ripples is counted by counting the signal. If it is not determined as a ripple in S7, or if it is determined as a ripple in S7 and the current is registered as a ripple in S8, the process returns to S2, and the extraction means 4 extracts the falling peak of the subsequent current. The extraction means 4 extracts the rising peak at.

  In addition, the control contents of the motor rotation speed detection device shown in FIG. 1 will be described using specific motor current waveforms. FIG. 3 is a schematic diagram showing a specific current input to the motor rotation speed detection device of this embodiment.

  When the current is of the form shown in FIG. 3A, the extracting means 4 extracts the rising peak A of the current α that drives the motor 7, and the extracting means 4 extracts the falling peak B and extracts it. The means 4 extracts the rising peak C, and since each peak data is an initial value, the update is not judged, and the amplitude of the current α is calculated from the peak data at three consecutive points of the current, and the storage means 2 To determine whether or not the current α is a ripple.

  In this case, it is determined that the current α is a ripple, the storage unit 2 registers the three points of peak data A, B, and C as ripples and outputs a ripple determination signal, and the count unit 6 outputs the ripple determination signal. The number of ripples is counted by counting. Further, the determination data stored in the storage means 2 is also updated by the peak data A, B, C.

  Further, as shown in FIG. 3B, the comparison / determination means 5 compares the three points of peak data C, D, and E of the subsequent current β with the updated determination data (peak data A, B, C). And determine if it is a ripple. Here, it is determined by comparison that there is no ripple.

  As shown in FIG. 3C, the peak data F and G at two points of the subsequent current β are such that the current value of the peak data F is larger than the current value of the peak data D, and the current value of the peak data G is the peak data E. Therefore, the peak data C, D of the three points are replaced by replacing the two most recent peak data D, E among the peak data C, D, E of the three points with both of the peak data F, G. , E are updated, and the comparison / determination means 5 compares the updated three-point peak data C, F, G with the determination data (peak data A, B, C) to determine whether or not it is a ripple. Again, it is determined by comparison that there is no ripple.

  Further, as shown in FIG. 3D, the peak data H and I at the two points of the subsequent current β are such that the current value of the peak data H is smaller than the current value of the peak data F, and the current value of the peak data I is the peak. Since the current value of the data G is smaller than the peak data I, the peak data G of the three points is replaced only by the peak data I, and the peak data C, F, G of the three points are updated, and comparison judgment is performed. The means 5 compares the updated peak data C, F, I of the three points with the determination data (peak data A, B, C) to determine whether it is a ripple. Here, it is determined as a ripple by comparison, and as shown in FIG. 3 (e), the storage unit 2 registers the peak data C, F, and I of the three points as a ripple and outputs a ripple determination signal. The count means 6 counts the number of ripples by counting the ripple determination signal.

  Thus, even a waveform distorted by noise is stored as peak data at three points, and it can be determined whether or not it is a ripple by comparing with the peak data at three points stored in the storage means 2. Ripple determination accuracy can be increased without increasing the capacity of the storage medium.

  In the flowchart shown in FIG. 2, the comparison is made after obtaining the amplitude of the ripple and the amplitude of the current determined from the comparison data from the peak data of the three points of the judgment data and the peak data of the three points of the current to be compared. However, the amplitude and period may be obtained and compared. A flowchart in this case is shown in FIG. Compared with the flowchart shown in FIG. 2, the only difference is that the period is also calculated in S17 in parallel with S16.

  In the flowcharts shown in FIG. 2 and FIG. 4, the peak data at three consecutive points of current are extracted in a pattern of rising peak (minimum value) → falling peak (maximum value) → rising peak (minimum value). In this case, however, the current to be extracted has a mountain-shaped waveform protruding upward. As shown in FIG. 5, this is an effective technique applied to a motor in which noise is likely to be superimposed on the waveform on the upper side of the current.

  Of course, as shown in FIG. 6, it is preferable to use the method of the flowchart shown in FIG. 7 instead of the above method in a motor in which noise is likely to be superimposed on the lower waveform of the current. That is, the peak data of three consecutive currents are extracted in a pattern of falling peak (maximum value) → rising peak (minimum value) → falling peak (maximum value). That is, only the steps S1, S2, and S3 are different, and the other steps are the same as those shown in FIG.

  Whether noise is likely to be superimposed on the upper waveform of the current or whether noise is likely to be superimposed on the lower waveform of the current depends on errors in the manufacture of the brush and commutator of the DC motor and wear over time. It is decided by.

  As a result, it is possible to improve the ripple determination accuracy without increasing the capacity of the storage medium 2 of the storage means 2 to be used, and to increase the detection accuracy of the motor ripple detection device and thus the rotation speed detection device.

  For example, when the present embodiment is applied to a memory sheet system, in a DC motor that outputs 20 ripples per revolution, if an erroneous determination of 8 ripples occurs due to noise, the actual motor speed is 20 If the maximum movement distance in the sliding direction of the memory sheet is 240 mm, it is determined that the movement is 240 mm even though the movement is only 240 × 20/28 = 171 mm. As a result, an error of up to 69 mm occurs. However, according to the embodiment of the present invention, it is possible to improve the determination accuracy of the ripple, and thus it is possible to prevent the occurrence of these errors.

  The first embodiment described above is suitable for application when the peak data of three adjacent ripples immediately before the three peak data to be compared can be compared. However, as described above, it may be preferable to compare the current with the previous ripple rather than the adjacent ripple.

  For example, as shown in FIG. 15, the noise in the frequency band that is half the ripple frequency is large. In this case, as shown in FIG. 16, when conditions with large load fluctuations overlap, it is necessary to compare the peak data or current waveform of the previous two ripples and current, and in that case, the comparison In this case, as shown in FIG. 17, if the current is distorted due to the influence of noise, all the distorted current waveforms are determined as ripples, and the erroneous determination of ripples may increase. There is sex.

  Therefore, the present invention also provides a second embodiment described below.

  That is, as shown in FIG. 1, storage means 2 for storing three-point peak data serving as determination data as to whether or not it is ripple, detection means 3 for detecting motor current by A / D conversion, Extraction means 4 for extracting peak data at three consecutive points of current detected by the detection means 2, comparison determination means 5 for determining whether the peak data at three consecutive points of the current are ripples, and comparison determination The means 5 compares the peak data of the three points stored by the storage means 2 with the peak data of the three currents extracted by the extraction means 3, and the continuous peak data of the current is a ripple. And the counting means 6 for counting the peak data at three points as ripples when the determination is made, and the number of rotations of the motor is detected from the number of ripples counted by the counting means 6. In the motor rotation speed detecting device, the comparison / determination means 5 classifies the ripples by comparing the rising and falling amplitudes of the ripples, detects an erroneous determination of ripples by combining consecutive ripple classes, and the ripple Subtract and correct the count number.

  Specific examples of ripple classification are shown below. FIG. 9 is a schematic diagram showing a specific example of the classification of the motor rotation speed detection device according to the present invention.

  For example, when the ripple rising amplitude is larger than the falling amplitude, or the ratio of the rising amplitude to the falling amplitude is equal to or greater than a certain threshold, the class A is set.

  Further, when the falling amplitude is larger than the rising amplitude, or the ratio of the rising amplitude to the falling amplitude is equal to or greater than a certain threshold, the class B is set.

  Furthermore, when the ratio of the rising amplitude to the falling amplitude is equal to or less than a certain threshold, the class C is set.

  In view of the above, it is detected whether or not there has been a ripple misjudgment using the ripple misjudgment detection table shown in FIG. When the combination of the two previous ripples determined and detected as the ripple and the newly detected ripple class is A, B, or B, A, it is detected that there is an erroneous determination of the ripple.

  For example, when a current as shown in FIG. 11 is input to the motor rotation speed detection device according to the present invention, the first current pulse α is classified as class C, and the next current pulse β is classified as class C. . Subsequently, the current pulse γ is classified as class A, the subsequent current pulse δ is classified as class C, the further current pulse ε is classified as class B, and each current pulse γ, δ, ε is divided into two. Compared with the previous current pulses α, β, γ, and when all are determined and registered as ripples due to the large comparison threshold, the ripple is determined based on the ripple misjudgment table shown in FIG. Since the two previous registered ripple (current pulse γ) classes and the newly registered ripple (current pulse ε) classes are A and B, it is detected that there is an erroneous determination of ripple, and the ripple count Correct subtract number. Thereby, the determination accuracy and detection accuracy of the ripple can be increased, and the detection accuracy of the rotational speed of the motor can be increased.

  FIG. 12 shows the control content described above in a flowchart.

  In S21, the extracting means 4 extracts the rising peak of the current that drives the motor 7. In S22, the extracting means 4 extracts the falling peak. In S23, the extracting means 4 extracts the rising peak. In S24, each extracting peak is extracted. The amplitude is calculated from the peak data and classified in S25 by comparing the rising and falling amplitudes of the currents. Then, in S26, the comparison / determination unit 5 stores the previous two stored in the storage unit 2. Is compared with the amplitude of the current to determine whether the current is a ripple.

  If it is determined that the current is a ripple, the ripple is registered in S27, and a ripple determination signal is output and the counting means 6 counts the number of ripples. In S28, when it is detected that there is no erroneous determination of ripple by class comparison (comparison of class combinations) with the previous two ripples, the process returns to S22, and when it is detected that there is an erroneous determination, In S29, the comparison determination means 5 outputs an erroneous determination signal, and in S30, the counting means 8 that has received the erroneous determination signal subtracts and corrects the ripple count.

  In the flowchart shown in FIG. 12, as in the flowchart shown in FIG. 2, the peak data is updated under predetermined conditions with the peak data at the two points of the subsequent current, and then compared with the determination data. Thus, it can be determined whether or not the current is ripple. In that case, the flowchart of FIG. 12 is modified to a flowchart as shown in FIG. That is, step S34 shown in FIG. 13 is performed after peak data extraction.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications and substitutions are made to the above-described embodiment without departing from the scope of the present invention. be able to.

  The present invention relates to a rotational speed detection of a DC motor applied to a memory seat system, a power window device, a sunroof device, etc. of an automobile, and can detect the rotational speed without using a speed detection device such as an encoder. In addition, since the detection accuracy can be improved, it can be applied to various automobiles.

It is a block diagram which shows one Example of the rotation speed detection apparatus of the motor by this invention. It is a flowchart which shows the control content of one Example of the rotation speed detection apparatus of the motor by this invention. It is a schematic diagram which shows an example of the electric current input into the rotation speed detection apparatus of the motor by this invention, and the control content with respect to it. It is a flowchart which shows the control content of one Example of the rotation speed detection apparatus of the motor by this invention. It is a schematic diagram which shows an example of the electric current input into the rotation speed detection apparatus of the motor by this invention. It is a schematic diagram which shows an example of the electric current input into the rotation speed detection apparatus of the motor by this invention. It is a flowchart which shows the control content of one Example of the rotation speed detection apparatus of the motor by this invention. It is a schematic diagram which shows an example of the electric current input into the rotation speed detection apparatus of the motor by this invention, and the control content with respect to it. It is a schematic diagram which shows an example of the electric current input into the rotation speed detection apparatus of the motor by this invention, and classification with respect to it. It is a ripple misjudgment table used for the detection of the misjudgment of the ripple of the rotation speed detection apparatus of the motor by this invention. It is a schematic diagram which shows an example of the electric current input into the rotation speed detection apparatus of the motor by this invention, and the control content with respect to it. It is a flowchart which shows the control content of one Example of the rotation speed detection apparatus of the motor by this invention. It is a flowchart which shows the control content of one Example of the rotation speed detection apparatus of the motor by this invention. It is a schematic diagram which shows the relationship of an example of the input current in the conventional rotation speed detection apparatus of a motor, and the erroneous determination of a ripple. It is a schematic diagram which shows an example of the input current in the rotation speed detection apparatus of the conventional motor. It is a schematic diagram which shows an example of the input current in the rotation speed detection apparatus of the conventional motor. It is a schematic diagram which shows an example of the input current in the rotation speed detection apparatus of the conventional motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor rotation speed detection apparatus 2 Memory | storage means 3 Detection means 4 Extraction means 5 Comparison determination means 6 Count means 7 Motor 8 Motor control means

Claims (8)

  Storage means for storing peak data at three points, which are judgment data as to whether or not it is ripple, detection means for detecting the current for driving the motor, and extraction for extracting the peak data of the current detected by the detection means And a comparison / determination unit that determines whether or not the peak data of the three consecutive points of the current are ripples, and the comparison / determination unit stores the three-point peak data stored in the storage unit and the 3. A motor ripple detection device comprising: comparing peak data at three consecutive points of current extracted by an extracting means to determine that peak data at three consecutive points of current is ripple.   The comparison / determination unit compares the peak data of the three points stored by the storage unit with the peak data of the three points of continuous current extracted by the extraction unit, and the peak of the three points of continuous current When it is determined that the data is not ripple, and the two points of peak data following the three points of continuous peak data of the current satisfy a predetermined condition, the extraction means uses the two points of peak data to determine the three points. The peak data at the two most recent points are replaced with the peak data at the three points, and the peak data at the three points are updated, and the comparison / determination unit determines that the updated three-point peak data is stored in the storage unit The motor ripple detection device according to claim 1, wherein it is determined whether the ripple is compared with the peak data of three points as data.   When the comparison determination unit determines that the peak data of three consecutive points of current extracted by the extraction unit is ripple, the determination stored in the storage unit by the peak data of three consecutive points of the current 3. The motor ripple detection apparatus according to claim 1, wherein peak data at three points as data is updated.   The comparison / determination unit obtains the amplitude of the ripple determined by the determination data from the three points of peak data stored in the storage unit, and the amplitude of the current from the peak data of three consecutive points of the current detected by the detection unit. 4. The motor ripple detection device according to claim 1, wherein a determination is made as to whether or not the peak data at three consecutive points of the current are ripples by comparing the amplitudes thereof.   The comparison / determination unit obtains the period and amplitude of the ripple determined by the determination data from the peak data of the three points stored in the storage unit, and the current is determined from the peak data of the three consecutive points of the current detected by the detection unit. The period and the amplitude of the current are obtained, and it is determined whether the peak data of the three consecutive points of the current are ripples by comparing the period and the amplitude. Motor ripple detection device.   The comparison / determination means classifies the ripple determined as the ripple by comparing the rising amplitude and the falling amplitude of the ripple, and detects an erroneous determination of the ripple when the combination of consecutive ripple classes is a predetermined combination. The motor ripple detection device according to claim 1, wherein the motor ripple detection device is a motor ripple detection device. Storage means for storing a ripple waveform of current as determination data, detection means for detecting a current for driving the motor, extraction means for extracting a current waveform within a predetermined period of the current detected by the detection means, and extraction And a comparison / determination unit that determines whether or not the current waveform is ripple, and the comparison / determination unit compares the ripple waveform stored in the storage unit with the current waveform extracted by the extraction unit. A ripple detection device for a motor that determines that the current waveform is ripple,
The comparison determination unit classifies the ripples by comparing the rising amplitude and the falling amplitude of the ripples, and detects an erroneous determination of the ripple when the combination of consecutive ripple classes is a predetermined combination. Motor ripple detection device.   A motor ripple detection device according to claim 1 and a counting means for counting ripples determined to be ripples by the ripple detection device, and a motor based on the number of ripples counted by the counting means. An apparatus for detecting the number of rotations of a motor is provided.

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