JP2024027420A - Motor drive control device and motor diagnosis method - Google Patents

Abstract

The present disclosure provides a motor drive control device capable of detecting abnormality in a motor. A motor drive control device for driving a motor, comprising a control unit, the control unit including (a) a step of calculating a variance-covariance matrix based on a plurality of variables indicating the operating state of the motor; , (b) a procedure for obtaining a precision matrix that is an inverse matrix of the variance-covariance matrix, (c) a procedure for regularizing the precision matrix to obtain a regularized precision matrix, and (d) a procedure for obtaining a regularized precision matrix by regularizing the precision matrix. (e) determining the combination of correlated variables from the plurality of variables based on the combination; and (e) estimating the occurrence of an abnormality in the motor based on the combination. [Selection diagram] Figure 1

Description

The present disclosure relates to a motor drive control device and a motor diagnosis method.

2. Description of the Related Art As a means for detecting an abnormality in a motor, there is known a means for detecting an abnormality by attaching a sensor to the motor. For example, a method is known in which a magnetic sensor is attached between a stator and a rotor and an electromagnetic field around the motor is analyzed to detect abnormalities in the motor. Furthermore, a method is known in which a temperature sensor such as a thermistor is attached near a bearing or a winding, and temperature changes in the motor are analyzed to detect abnormalities in the motor. Furthermore, a method is known in which a vibration sensor is attached to the stator or rotor to analyze the vibration of the motor and detect abnormalities in the motor. Furthermore, a method is known in which an acoustic sensor is attached to the stator or rotor to analyze the sound generated when the motor is driven to detect abnormalities in the motor.

For example, Patent Document 1 discloses a remaining life diagnosis method using an acceleration sensor.

Further, as a means for detecting abnormalities in a motor, current symptom analysis is known in which an electric signal during motor drive is analyzed without using a sensor. For example, when a motor bearing is damaged and misaligned, changes in the air gap, changes in rotor resistance, etc. affect the current through spatial magnetic flux lines. Therefore, when fast Fourier transform analysis is performed on a current signal in a motor with an abnormality, the harmonic components in the low frequency band of the current flowing through the motor increase. Motor abnormality is detected by detecting an increase (change) in harmonic components in the low frequency band of the current as a sign of abnormality. Current signature analysis, which analyzes electrical signals when a motor is driven, does not require a sensor to be attached to each motor.

For example, Patent Document 2 discloses a motor diagnostic device that outputs an alarm when a sideband wave with a signal strength equal to or higher than a set value is extracted.

Japanese Patent Application Publication No. 2010-190901 Japanese Patent Application Publication No. 2016-195524

Motor abnormality detection means using sensors generally uses a plurality of sensors to analyze mutual data. In the case of large and expensive motors, such as motors for industrial equipment, the ratio of sensor price to motor price is low, so the price will not increase significantly. However, in the case of relatively inexpensive motors such as fan motors for servers, the rate of increase in price for sensors is expected to be large, making it difficult to accept them in the market.

In addition, motor abnormality detection means that do not use sensors require the preparation of a separate oscilloscope to obtain the current waveform. Data will be acquired and analyzed. Furthermore, since fast Fourier transform analysis requires a large amount of calculation, real-time detection is difficult.

The present disclosure provides a motor drive control device that can detect abnormality in a motor.

One aspect of the present disclosure is a motor drive control device that drives a motor, including a control unit, the control unit (a) calculating a variance-covariance matrix based on a plurality of variables indicating operating states of the motor. (b) a procedure for obtaining a precision matrix that is an inverse matrix of the variance-covariance matrix; (c) a procedure for regularizing the precision matrix to obtain a regularized precision matrix; and (d) the regularization. A motor drive control device that executes a step of determining a combination of correlated variables from the plurality of variables based on an accuracy matrix; and (e) a step of estimating the occurrence of an abnormality in the motor based on the combination. is provided.

According to the motor drive control device of the present disclosure, abnormality in the motor can be detected.

FIG. 1 is a diagram schematically showing a motor system in which a motor drive control device according to the present embodiment is used. FIG. 2 is a flow diagram illustrating processing in the motor drive control device according to the present embodiment. FIG. 3 is a diagram illustrating the operation results of the motor drive control device according to the present embodiment. FIG. 4 is a diagram illustrating calculation results in the motor drive control device according to the present embodiment. FIG. 5 is a diagram illustrating calculation results in the motor drive control device according to the present embodiment. FIG. 6 is a diagram illustrating calculation results in the motor drive control device according to the present embodiment. FIG. 7 is a diagram illustrating calculation results in the motor drive control device according to the present embodiment. FIG. 8 is a diagram illustrating calculation results in the motor drive control device according to the present embodiment. FIG. 9 is a diagram illustrating calculation results in the motor drive control device according to the present embodiment. FIG. 10 is a diagram illustrating calculation results in the motor drive control device according to the present embodiment.

≪Motor system≫
Hereinafter, a motor system in which a motor drive control device according to the present embodiment is used will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing a motor system 1 in which a motor drive control device 100, which is an example of a motor drive control device according to the present embodiment, is used.

The motor system 1 includes a motor 10 and a motor drive control system 20. The motor 10 is used, for example, to rotate a fan. The motor drive control system 20 drives and controls the motor 10.

The motor drive control system 20 includes a motor drive control device 100 and a host device 200.

<Motor drive control device 100>
The motor drive control device 100 includes a motor drive circuit 101, a sensor section 102, and a frequency generator (FG) signal generation section 103. The motor drive control device 100 also includes a power supply voltage measurement section 110, a drive control signal generation section 120, a communication section 130, a current measurement section 140, a rotation speed measurement section 150, an abnormality detection control section 160, and a data A management section 170 is provided.

Note that the drive control signal generation section 120, rotation speed measurement section 150, abnormality detection control section 160, and data management section 170 in the motor drive control device 100 are realized by, for example, a program processing device (computer). More specifically, the program processing device includes a processor such as a CPU (Central Processing Unit), and various storage devices such as a RAM (Random Access Memory) and a ROM (Read Only Memory). In addition, the program processing device includes peripherals such as a counter (timer), an AD (analog-to-digital) conversion circuit, a DA (digital-to-analog) conversion circuit, a clock generation circuit, and an input/output I/F (interface) circuit. Equipped with a circuit. For example, a processor, a storage device, and a peripheral circuit are each connected to each other via a bus or a dedicated line. The program processing device is, for example, a microcontroller. In a program processing device, a CPU implements processing by executing various arithmetic operations according to programs stored in a memory.

[Motor drive circuit 101]
The motor drive circuit 101 drives the motor 10 based on the drive control signal Ctl generated by the drive control signal generation section 120. The motor drive circuit 101 includes, for example, a predrive circuit and an inverter circuit.

The predrive circuit generates an output signal for driving the inverter circuit based on the drive control signal Ctl. The predrive circuit outputs the generated output signal to the inverter circuit. The predrive circuit generates and outputs a drive signal for driving each switch element of the inverter circuit, based on the drive control signal Ctl, for example.

The inverter circuit outputs a drive signal to the motor 10 based on the output signal output from the predrive circuit. The drive signal output by the inverter circuit energizes a coil included in the motor 10. In an inverter circuit, for example, two switch elements provided at both ends of a DC power supply, for example, a pair of series circuits of transistors such as field effect transistors, are connected to coils of each phase. In each pair of two switch elements, a terminal of each phase of the motor 10 is connected to a connection point between the switch elements.

The drive signal generated by the predrive circuit turns on and off each switch element constituting the inverter circuit, so that power is supplied to each phase of the motor 10 and the rotor of the motor 10 rotates.

The motor drive circuit 101 is supplied with power from a power source 210 included in the host device 200 . The motor drive circuit 101 is connected to a power source 210 included in the host device 200 . The motor drive circuit 101 converts the power supplied from the power supply 210 based on the drive control signal Ctl. The motor drive circuit 101 then supplies the converted power to the motor 10.

[Sensor section 102]
The sensor unit 102 detects the rotational position of the rotor of the motor 10. The sensor unit 102 includes, for example, a position sensor. The sensor section 102 includes, for example, a Hall element. The Hall element of the sensor section 102 detects the magnetic poles of the rotor. The Hall element of the sensor unit 102 outputs a Hall signal whose voltage changes according to the rotation of the rotor.

Note that the position sensor of the sensor section 102 is not limited to a Hall element. The position sensor may be any sensor that can detect the rotational position of the rotor of the motor. For example, an encoder or the like may be used as the position sensor. When using an encoder as a position sensor, the sensor unit 102 is provided outside the motor drive control device 100, not as one of the components of the motor drive control device 100, but as a device independent from the motor drive control device 100. It may be.

[FG signal generation unit 103]
The FG signal generation unit 103 generates an FG signal as a rotational speed signal indicating the rotational speed of the motor 10. The FG signal generation unit 103 generates a signal (FG signal) having a period (frequency) proportional to the rotational speed of the motor 10, based on the detection signal (Hall signal) output from the Hall element of the sensor unit 102, for example. do. The FG signal output from the FG signal generation section 103 is input to the host device 200. Note that the FG signal generation unit 103 may be realized by, for example, an FG pattern formed on a board (printed board) on which the motor 10 is mounted.

[Power supply voltage measuring section 110]
The power supply voltage measurement unit 110 measures the voltage V of power supplied from the host device 200. In other words, the power supply voltage measuring section 110 measures the power supply voltage. Power supply voltage measurement section 110 outputs the measured voltage value Vm to abnormality detection control section 160.

[Drive control signal generation unit 120]
The drive control signal generation unit 120 generates a drive control signal Ctl for controlling the drive of the motor 10. The drive control signal generation unit 120 receives, for example, a speed command signal Sv that is a drive command signal output from the host device 200 as a drive command. When the drive control signal generation unit 120 receives the speed command signal Sv, it generates the drive control signal Ctl so that the rotational speed of the motor 10 matches the target rotational speed specified by the speed command signal Sv.

The drive control signal Ctl is, for example, a PWM (Pulse Width Modulation) signal.

The drive control signal generation section 120 includes a speed command analysis section 121, a duty ratio determination section 122, and an energization control section 123.

(Speed command analysis unit 121)
The speed command analysis unit 121 receives the speed command signal Sv output from the host device 200. Then, the speed command analysis unit 121 analyzes the target rotational speed specified by the speed command signal Sv. For example, if the speed command signal Sv is a PWM signal having a duty ratio corresponding to the target rotational speed, the speed command analysis section 121 analyzes the duty ratio of the speed command signal Sv, and calculates the rotational speed corresponding to the duty ratio. Outputs information as target rotation speed.

(Duty ratio determination unit 122)
The duty ratio determination unit 122 generates a PWM signal as the drive control signal Ctl based on the target rotation speed output from the speed command analysis unit 121 and the measured value of the rotation speed of the motor 10 measured by the rotation speed measurement unit 150. Determine the duty ratio of

Specifically, the duty ratio determining unit 122 calculates the control value of the motor 10 such that the difference between the target rotation speed and the measured value of the rotation speed of the motor 10 becomes small. Then, the duty ratio determination unit 122 determines the duty ratio of the PWM signal according to the calculated control value. For example, the duty ratio determining unit 122 performs control using one of PID (Proportional-Integral-Differential) control, PD control, and PI control so that the difference between the target rotation speed and the measured value of the rotation speed of the motor 10 becomes small. Calculate the value. Then, the duty ratio determination unit 122 determines the duty ratio Dty of the PWM signal according to the control value.

Duty ratio determination section 122 outputs the determined duty ratio Dty to abnormality detection control section 160.

(Electrification control unit 123)
The energization control section 123 generates a PWM signal having the duty ratio determined by the duty ratio determination section 122. Then, the energization control unit 123 outputs the generated PWM signal to the motor drive circuit 101 as a drive control signal Ctl.

[Communication Department 130]
The communication unit 130 communicates with the outside. The communication unit 130 communicates with the host device 200. Specifically, the communication unit 130 transmits and receives data to and from the host device 200 as a control device. The communication section 130 includes a transmission section 131, a reception section 132, and a communication control section 133.

The transmitter 131 transmits data to the host device 200. The receiving unit 132 receives data from the host device 200. Each of the transmitter 131 and the receiver 132 is controlled by a communication controller 133. The transmitter 131 is, for example, a serial communication interface circuit that generates a predetermined serial signal and transmits it to a communication line. Further, the receiving unit 132 is, for example, a serial communication interface circuit that generates a predetermined serial signal and receives the serial signal from a communication line.

The communication control section 133 controls each of the transmitting section 131 and the receiving section 132. The communication control section 133 sends the encoded data to the transmission section 131. Furthermore, the communication control unit 133 decodes data received from the reception unit 132. The communication control section 133 transmits and receives data to and from the host device 200 by controlling the transmitting section 131 and the receiving section 132 . The communication control unit 133 is realized, for example, by program processing by a processor included in the motor drive control device 100.

The communication control unit 133 receives the speed command signal Sv output from the host device 200 as a drive command. The communication control unit 133 then transmits the received speed command signal Sv to the speed command analysis unit 121.

[Current measurement unit 140]
The current measurement unit 140 measures the current of the power supplied from the motor drive circuit 101 to the motor 10 . The current measurement unit 140 includes, for example, a current transformer. The current measurement unit 140 outputs a current value Im obtained by measuring the current of the power supplied from the motor drive circuit 101 to the motor 10 to the abnormality detection control unit 160.

[Rotation speed measurement unit 150]
The rotational speed measurement unit 150 measures the rotational speed of the motor 10. The rotation speed measuring section 150 measures the rotation speed of the motor 10 based on, for example, a detection signal (Hall signal) of a Hall element in the sensor section 102. The rotational speed measurement section 150 outputs the measured rotational speed Rm to the abnormality detection control section 160.

[Abnormality detection control unit 160]
The abnormality detection control unit 160 detects an abnormality in the motor 10. The abnormality detection control unit 160 estimates and detects the occurrence of an abnormality in the motor 10 based on the voltage value Vm, current value Im, rotational speed Rm, and duty ratio Dty.

[Data management section 170]
The data management unit 170 manages data.

<Upper device 200>
Next, the host device 200 will be explained. The host device 200 supplies power to the motor drive control device 100. Further, the host device 200 instructs the motor drive control device 100 about the rotation speed. The host device 200 includes a power supply 210, a data processing control section 220, and a communication section 230.

[Power supply 210]
Power supply 210 supplies power to motor drive control device 100 to operate motor 10 . Power supply 210 is a DC power supply. The power supply 210 supplies, for example, 12V (volt) power to the motor drive control device 100.

[Data processing control unit 220]
The data processing control unit 220 instructs the motor drive control device 100 about the target rotational speed (target rotational speed) of the motor 10 . The data processing control section 220 transmits the speed command signal Sv to the motor drive control device 100 via the communication section 230. The data processing control unit 220 instructs the motor drive control device 100 about a target rotation speed (target rotation speed) by transmitting a speed command signal Sv to the motor drive control device 100.

[Communication Department 230]
The communication unit 230 communicates with the motor drive control device 100. Communication unit 230 communicates with communication unit 130 in motor drive control device 100 . The communication unit 230 receives the signal transmitted from the transmission unit 131 in the communication unit 130 as a received signal Rx. Furthermore, the communication unit 230 transmits the transmission signal Tx to the reception unit 132 in the communication unit 130. The communication unit 230 is, for example, a serial communication interface circuit that generates a predetermined serial signal and transmits and receives the serial signal from a communication line.

<Processing in the abnormality detection control unit>
Next, the processing performed by the abnormality detection control unit 160 will be explained. By explaining the processing performed by the abnormality detection control unit 160, the steps included in the motor diagnosis method performed by the motor drive control device 100 for diagnosing an abnormality in the motor 10 will be explained. FIG. 2 is a flow diagram illustrating processing in the motor drive control device 100, which is an example of the motor drive control device according to the present embodiment.

The inventors have found that it is difficult to detect an abnormality in the motor 10 using a single variable that indicates the operating state of the motor 10. Then, by focusing on the relationships among multiple variables that indicate the operating state of the motor 10 and sparsifying the index that indicates the relationships between the multiple variables, it is possible to detect abnormalities in the motor 10 with higher accuracy. I found it.

(Step S10)
First, the abnormality detection control unit 160 acquires data regarding a plurality of variables indicating the operating state of the motor 10 during a predetermined period. Specifically, the abnormality detection control unit 160 acquires data on a voltage value Vm that is a power supply voltage, a current value Im of a current supplied to the motor 10, a rotational speed Rm of the motor 10, and a duty ratio Dty. The abnormality detection control unit 160 stores, for example, each of the voltage value Vm, current value Im, rotational speed Rm, and duty ratio Dty during a predetermined period in the data management unit 170. Then, each of the voltage value Vm, current value Im, rotational speed Rm, and duty ratio Dty is read out and acquired from the data management unit 170.

(Step S20)
Next, the abnormality detection control unit 160 calculates a variance-covariance matrix S for the voltage value Vm, current value Im, rotational speed Rm, and duty ratio Dty during the acquired predetermined period.

The variance-covariance matrix S is calculated based on Equation 1. Note that X ^d represents input data that is a multivariate vector, and μ represents an average.

(Step S30)
Next, the anomaly detection control unit 160 obtains an accuracy matrix Λ from the obtained variance-covariance matrix S. The precision matrix Λ is the inverse of the variance-covariance matrix S. The accuracy matrix Λ is calculated based on Equation 2.

(Step S40)
Next, the abnormality detection control unit 160 calculates an accuracy matrix to which the regularization term is added. Correlation coefficients can be cited as a means of viewing features between data in a plurality of data. However, when a correlation coefficient is used, there is an apparent correlation, so it is difficult to clearly distinguish from the numerical value of the correlation coefficient. For example, if the correlation coefficient is in the range of 0.3 to 0.7, it is considered that there is a weak correlation, and there may be ambiguity as to whether there is a correlation.

Therefore, the abnormality detection control unit 160 obtains a variance-covariance matrix S from a plurality of data in order to eliminate the apparent phase difference, and obtains an accuracy matrix Λ from the variance-covariance matrix S. Then, ambiguity is eliminated by adding a regularization term to the precision matrix Λ.

That is, the anomaly detection control unit 160 adds a regularization term to the accuracy matrix Λ to make the accuracy matrix Λ sparse, thins out unimportant variables, and extracts only important variables.

A precision matrix to which a regularization term is added is sometimes called a regularization precision matrix. The accuracy matrix including the regularization term is obtained in the process of solving the estimation problem. In other words, each of the accuracy matrix and the variance-covariance matrix to which the regularization term has been added is obtained by calculating the maximum likelihood estimated value of each of the accuracy matrix and the variance-covariance matrix from the log-likelihood function.

Equation 3 is a log-likelihood function of a multidimensional normal distribution.

Note that det represents a determinant. const represents a constant. Equation 3 is transformed into Equation 4.

Note that tr represents a matrix trace.

An optimization problem is solved in which a regularization term is added to the log-likelihood function of Equation 4, and each parameter of the accuracy matrix and the variance-covariance matrix is estimated. To maximize the likelihood, minimize what is in the parentheses of Equation 4.

Equation 5 represents an optimization problem with the addition of a regularization term. Λ ^* is a precision matrix (regularized precision matrix) to which a regularization term is added.

Note that ρ||Λ|| ₁ indicates a regularization term. ρ indicates a hyperparameter.

The precision matrix Λ ^* obtained by Equation 5 is the precision matrix that is the solution of maximum likelihood estimation to which the regularization term is added. That is, the precision matrix Λ ^* is the regularized precision matrix.

(Step S50)
Next, the abnormality detection control unit 160 determines whether there is an abnormality. The abnormality detection control unit 160 examines the coefficients between each of the voltage value Vm, current value Im, rotational speed Rm, and duty ratio Dty in the regularized precision matrix Λ ^* with other variables. That is, the abnormality detection control unit 160 examines non-diagonal components in the regularized accuracy matrix Λ ^* .

In the regularized precision matrix Λ ^* , off-diagonal components corresponding to combinations with no correlation become zero. On the other hand, in the regularized precision matrix Λ ^* , off-diagonal components corresponding to correlated combinations take values other than zero. A combination of correlated variables is determined from multiple variables from off-diagonal components that are non-zero values.

As described later, in the regularization accuracy matrix Λ ^* , if there is a correlation only between the voltage value Vm and the current value Im, in other words, the only combination that has a correlation is the voltage value Vm and the current value Im. In this case, the abnormality detection control unit 160 estimates that the motor 10 is normal. On the other hand, if there is a correlation between the duty ratio Dty and at least one of the voltage value Vm and the current value Im in the regularization accuracy matrix Λ ^* , the abnormality detection control unit 160 determines that the motor 10 is Estimate that there is a possibility. In other words, in the regularization accuracy matrix ^Λ The unit 160 estimates the occurrence of an abnormality in the motor 10.

As described above, the abnormality detection control unit 160 estimates the occurrence of an abnormality in the motor based on a combination of correlated variables. More specifically, the abnormality detection control unit 160 estimates the occurrence of an abnormality when a combination of correlated variables that is different from a combination of correlated variables during normal operation is detected.

(Step S60)
Next, the abnormality detection control unit 160 determines whether to end the process. If the process is to be ended (Yes in step S60), the abnormality detection control unit 160 ends the process. If the process does not end, in other words, if the process continues (No in step S60), the abnormality detection control unit 160 returns to step S10 and repeats the process.

<Operation results of motor drive control device>
Next, the operation results when operating the motor drive control device 100, which is an example of the motor drive control device according to the present embodiment, will be explained.

FIG. 3 is a diagram illustrating the operation results of the motor drive control device 100, which is an example of the motor drive control device according to the present embodiment. FIG. 3 is a diagram showing the operation results when a fan is attached to the motor 10 and the motor system 1 is used as a fan motor. FIG. 3 shows data from when the motor system 1 is operated until the motor 10 stops.

The horizontal axis in FIG. 3 shows the time since the motor 10 started operating, and the vertical axis shows the intensity of the variable used for estimation. Note that one unit of time on the horizontal axis is 20 seconds. That is, 20,000 on the horizontal axis indicates approximately 5 days. The vertical axis indicates the value of each of the plurality of variables normalized to a numerical value ranging from 0 to 1 in order to display the values of the plurality of variables on the same graph.

A line Lv shows the result of normalizing the voltage value Vm. A line Li shows the result of normalizing the current value Im. A line Ld shows the result of normalizing the duty ratio Dty. A line Lr shows the result of normalizing the rotational speed Rm. The rotation speed Rm is, for example, 13,000 revolutions per minute. The voltage value Vm is approximately 12V (volts).

In FIG. 3, at time Ts, which is approximately 165,000 hours, motor 10 has stopped. When the motor 10 stopped (time Ts), the bearing of the motor 10 was damaged.

Just by looking at the data in FIG. 3, it is not possible to determine where signs of abnormality begin to appear. In addition, in the data shown in FIG. 3, it can be confirmed that the voltage increases immediately before stopping, but it is too late to predict the life span.

Therefore, the motor drive control device 100 performs data mining based on the correlation between the four parameters: voltage value Vm, current value Im, duty ratio Dty, and rotation speed Rm. Correlation coefficients can be cited as a means of viewing features between data in a plurality of data. However, when a correlation coefficient is used, there is an apparent correlation, so it is difficult to clearly distinguish from the numerical value of the correlation coefficient. For example, if the correlation coefficient is in the range of 0.3 to 0.7, it is considered that there is a weak correlation, and there may be ambiguity as to whether there is a correlation.

Therefore, in order to eliminate the apparent phase difference, the motor drive control device 100 calculates a variance-covariance matrix S from a plurality of data, and calculates an accuracy matrix Λ from the variance-covariance matrix S. Then, ambiguity is eliminated by adding a regularization term to the precision matrix Λ.

In FIG. 3, time 20000 to time 40000 is period PRD1, time 40000 to time 60000 is period PRD2, time 60000 to time 80000 is period PRD3, and time 80000 to time 100000 is period PRD4. Furthermore, the period from time 100,000 to time 120,000 is set as period PRD5, the period from time 120,000 to time 140,000 is set as period PRD6, and the period from time 140,000 to time 160,000 is set as period PRD7.

For the four parameters, namely, the voltage value Vm, the current value Im, the duty ratio Dty, and the rotation speed Rm, the accuracy matrix (regularized accuracy matrix Λ ^* ) obtained by adding the variance-covariance matrix S and the regularization term in each period is calculated. It is shown in Tables 1 to 7. 4 to 10 show graphs showing the correlation between parameters for the accuracy matrix to which the regularization term has been added (regularized accuracy matrix Λ ^* ).

Note that in Tables 1 to 7 and FIGS. 4 to 10, "Voltage" indicates the voltage value Vm, "Current" indicates the current value Im, "Duty" indicates the duty ratio Dty, and "Rotation" indicates the rotation speed Rm.

Table 1, Table 2, Table 3, Table 4, Table 5, Table 6, and Table 7 show calculation results in period PRD1, period PRD2, period PRD3, period PRD4, period PRD5, period PRD6, and period PRD7, respectively. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9, and FIG. 10 show the addition of regularization terms in period PRD1, period PRD2, period PRD3, period PRD4, period PRD5, period PRD6, and period PRD7, respectively. A diagram in which variables whose off-diagonal components in the precision matrix (regularized precision matrix Λ ^* ) are other than zero are connected with lines.

In each of FIGS. 4 to 10, each of the four parameters, namely, the voltage value Vm (“Voltage”), the current value Im (“Current”), the duty ratio Dty (“Duty”), and the rotation speed Rm (“Rotation ”) are each indicated by an ellipse. A line connecting the ellipses indicates that there is a correlation between the ellipses. Note that the numerical values indicate corresponding off-diagonal components in the precision matrix (regularized precision matrix Λ ^* ) to which the regularization term is added.

In period PRD1, period PRD2, period PRD3, and period PRD4, current value Im (“Current”) and voltage value Vm (“Voltage”) are connected. That is, it is estimated that there is a correlation between the current value Im (“Current”) and the voltage value Vm (“Voltage”). On the other hand, each of the duty ratio Dty ("Duty") and the rotational speed Rm ("Rotation") is not connected to any of the others, and it is estimated that there is no correlation.

On the other hand, in period PRD5, the duty ratio Dty (“Duty”) is connected to the voltage value Vm (“Voltage”). That is, in the period PRD5, it is estimated that the voltage value Vm (“Voltage”) is correlated with each of the current value Im (“Current”) and the duty ratio Dty (“Duty).Furthermore, in the period PRD6, The duty ratio Dty (“Duty”) is further linked to the current value Im (“Current”). That is, in the period PRD6, it is estimated that the voltage value Vm (“Voltage”), the current value Im (“Current”), and the duty ratio Dty (“Duty)” are correlated with each other. The same is true in the period PRD7. .

Therefore, as in period PRD6, the abnormality detection control unit 160 is triggered by the appearance of a relationship in the regularization accuracy matrix between the current value Im (“Current”) and the duty ratio Dty (“Duty”). , the occurrence of an abnormality in the motor 10 is estimated. Specifically, from the period PRD1 to the period PRD5, the abnormality detection control unit 160 calculates the current value Im (“Current”) and the duty ratio Dty (“Duty '') is used as a trigger to estimate the occurrence of an abnormality in the motor 10. By predicting abnormalities during period PRD6, the life of the motor can be predicted about 6 days before the motor stops in FIG. 3. Note that, as in period PRD5, when a correlation appears between the voltage value Vm (“Voltage”) and the duty ratio Dty (“Duty”), as a trigger, the abnormality detection control unit 160 detects an abnormality in the motor 10. Occurrence may be estimated. Furthermore, even if there is no correlation between the voltage value Vm and the duty ratio Dty, the occurrence of a correlation between the current value Im ("Current") and the duty ratio Dty ("Duty") is used as a trigger to detect an abnormality. The detection control unit 160 may estimate the occurrence of an abnormality in the motor 10.

Note that the plurality of variables for determining the variance-covariance matrix S are not limited to the voltage value Vm, current value Im, duty ratio Dty, and rotation speed Rm, but other variables may be used. Furthermore, variables such as the rotational speed Rm that have no correlation before and after a failure may be deleted from the variables used to calculate the variance-covariance matrix S.

Note that the abnormality detection control unit 160 is an example of a control unit.

<Action/Effect>
According to the motor drive device according to this embodiment, abnormality in the motor can be detected.

Although the motor drive control device has been described above using the embodiments, the present invention is not limited to the above embodiments. Various modifications and improvements, such as combinations and substitutions with part or all of other embodiments, are possible within the scope of the present invention.

1 Motor system 10 Motor 20 Motor drive control system 100 Motor drive control device 101 Motor drive circuit 102 Sensor section 103 FG signal generation section 110 Power supply voltage measurement section 120 Drive control signal generation section 121 Speed command analysis section 122 Duty ratio determination section 123 Energization Control unit 130 Communication unit 131 Transmission unit 132 Receiving unit 133 Communication control unit 140 Current measurement unit 150 Rotation speed measurement unit 160 Abnormality detection control unit 170 Data management unit 200 Host device 210 Power supplies PRD1, PRD2, PRD3, PRD4, PRD5, PRD6, PRD7 period

Claims (6)

A motor drive control device that drives a motor,
Equipped with a control unit,
The control unit includes:
(a) a step of calculating a variance-covariance matrix based on a plurality of variables indicating the operating state of the motor;
(b) a procedure for obtaining an accuracy matrix that is an inverse matrix of the variance-covariance matrix;
(c) regularizing the accuracy matrix to obtain a regularized accuracy matrix;
(d) determining a combination of correlated variables from the plurality of variables based on the regularization accuracy matrix;
(e) a step of estimating the occurrence of an abnormality in the motor based on the combination;
execute,
Motor drive control device. The plurality of variables include a voltage value supplied to the motor, a current value supplied to the motor, a control value for driving the motor, and a rotation speed of the motor.
The motor drive control device according to claim 1. In the step (e), the control unit estimates the occurrence of an abnormality in the motor if there is a correlation between the voltage value and the control value;
The motor drive control device according to claim 2. In step (e), the control unit estimates the occurrence of an abnormality in the motor if there is a correlation between the current value and the control value;
The motor drive control device according to claim 2. In the step (e), if there is a correlation between the voltage value and the control value and a correlation between the current value and the control value, the control unit controls the motor. Estimate the occurrence of an abnormality,
The motor drive control device according to claim 2. A motor diagnostic method for diagnosing abnormalities in a motor, the method comprising:
(a) a step of calculating a variance-covariance matrix based on a plurality of variables indicating the operating state of the motor;
(b) a procedure for obtaining an accuracy matrix that is an inverse matrix of the variance-covariance matrix;
(c) regularizing the accuracy matrix to obtain a regularized accuracy matrix;
(d) determining a combination of correlated variables from the plurality of variables based on the regularization accuracy matrix;
(e) a step of estimating the occurrence of an abnormality in the motor based on the combination;
execute,
Motor diagnosis method.

Images