JP7068108B2 - Motor drive device and control method of motor drive device - Google Patents

Description

The present invention relates to a motor drive device for driving a motor using a three-phase AC power supply and a control method thereof.

In the motor drive device, a sensor that detects the phase current value of each phase is used in order to feed back the current flowing through each phase of the three-phase motor. If this sensor fails, the current flowing through each phase of the three-phase motor will not be fed back correctly, and overcurrent will tend to flow through each phase.

In Patent Document 1 below, a sensor that detects the phase current flowing in each of the three phases, an adder that calculates the sum of each phase current detected by the sensor, and a sum of the phase currents calculated by the adder. Disclosed is a motor anomaly detection device comprising a comparator that compares with and a predetermined value. In this abnormality detection device, when the total phase current exceeds a predetermined value, an abnormality in the sensor is detected. In this case, in the abnormality detection device, the contactor provided between the power supply and the power module is cut off, so that the power supply from the power supply is cut off.

Japanese Unexamined Patent Publication No. 6-25385

However, if the contactor is cut off when an abnormality is detected in the sensor, the supply of AC power from the three-phase AC power supply side to the rectifier is stopped, so the reverse converter outputs AC power for driving the motor. Since it cannot be operated, the normal operation of the motor cannot be continued. Therefore, if the motor is a motor for relatively moving the table on which the object to be machined is placed and the tool for machining the object to be machined, if an abnormality in the sensor is detected during machining, the object to be machined is to be machined. Can be out of control while the tool is in contact with the tool. Therefore, there is a concern that the tool may be damaged or processing defects may occur.

Therefore, an object of the present invention is to provide a motor drive device and a control method thereof that can prevent tool breakage and machining defects from occurring when an abnormality is detected in a sensor.

The first aspect of the present invention is a motor drive device for driving a motor using a three-phase AC power supply, which has a plurality of switching elements and a diode connected in parallel to each of the switching elements. The rectifier that converts the three-phase AC voltage supplied from the three-phase AC power supply into a DC voltage, the smoothing capacitor connected to the DC side of the rectifier, and the capacitor voltage stored in the smoothing capacitor are the three-phase AC voltage. A reverse converter that drives the motor using the three-phase AC voltage that has been reverse-converted to, a sensor that detects at least two-phase phase current values or phase voltage values flowing through the rectifier, and the sensor. The abnormality detection unit that detects the abnormality and the switching element are switched to charge the smoothing capacitor, and when a drive sensor abnormality occurs, which is an abnormality of the sensor when the motor is driven. Provides a control unit that stops the switching control and charges the smoothing capacitor by diode rectification of the rectifier.

A second aspect of the present invention is a method for controlling a motor drive device that drives a motor using a three-phase AC power supply, wherein the motor drive device is parallel to a plurality of switching elements and each of the switching elements. A rectifier having a diode connected to the rectifier and converting the three-phase AC voltage supplied from the three-phase AC power supply into a DC voltage, a smoothing capacitor connected to the DC side of the rectifier, and a smoothing capacitor stored in the smoothing capacitor. A reverse converter that reversely converts the capacitor voltage into the three-phase AC voltage and gives the reverse-converted three-phase AC voltage to the motor as a drive voltage, and at least two-phase phase current value or phase voltage value flowing through the rectifier. An initial charging step of charging the smoothing capacitor by diode rectification of the rectifier from the start of supply of the three-phase AC voltage to the time when the capacitor voltage reaches a predetermined voltage value. When a charging step of switching and controlling the switching element to charge the smoothing capacitor, an abnormality detection step of detecting an abnormality of the sensor, and a driving sensor abnormality which is an abnormality of the sensor during driving of the motor occur. Has a control step of stopping the switching control and charging the smoothing capacitor by diode rectification of the rectifier.

In the present invention, even if the switching control is stopped when the sensor is abnormal during the driving of the motor, the smoothing capacitor is charged by the diode rectification of the rectifier, and the inverse converter can output the AC power for driving the motor. As a result, when the motor is a motor for relatively moving the table on which the object to be machined is placed and the tool for machining the object to be machined, at least one of the table and the tool is moved to the retracted position. It becomes possible to drive a motor. Therefore, it is possible to prevent the tool from being damaged or processing defects.

It is a schematic diagram which shows the structure of the motor drive device in embodiment. It is a flowchart which shows the processing procedure of the initial charge process from the power-off state to the acquisition of the drive voltage of a motor. It is a flowchart which shows the processing procedure of the charge process after the initial charge process.

A motor drive device and a control method thereof according to the present invention will be described in detail below with reference to the accompanying drawings, with reference to suitable embodiments.

[Embodiment]
FIG. 1 is a schematic diagram showing the configuration of the motor drive device 10 according to the embodiment. The motor drive device 10 drives the motor M using a three-phase AC power supply P, and has a rectifier 12, a smoothing capacitor 14, an inverse converter 16, a motor controller 18, and a switching control unit 20 as components.

The rectifier 12 converts the three-phase AC voltage supplied from the three-phase AC power supply P into a DC voltage, and includes a plurality of switching elements 12a and a diode 12b connected in parallel to each switching element 12a. Has. Examples of the switching element 12a include an IGBT, a power MOSFET, a bipolar transistor, a thyristor, and the like. The diode 12b may be a parasitic diode.

The smoothing capacitor 14 smoothes the DC voltage converted by the rectifier 12, and is connected to the DC side of the rectifier 12. By charging the smoothing capacitor 14, the capacitor voltage is accumulated in the smoothing capacitor 14.

The inverse converter 16 converts the capacitor voltage stored in the smoothing capacitor 14 into a three-phase AC voltage, outputs the converted three-phase AC voltage, and drives the motor M. Like the rectifier 12, the inverse converter 16 has a plurality of switching elements 16a and a diode 16b connected in parallel to each switching element 16a. The diode 16b may be a parasitic diode.

The motor controller 18 controls the motor M. The motor M is a motor for relatively moving the table on which the object to be machined is placed with respect to the tool for processing the object to be machined. That is, the motor controller 18 generates a motor drive command for relatively moving the table so that the machining operation specified by the machining program is performed, and outputs the generated motor drive command to the switching control unit 20. The motor M may be a motor for moving the tool relative to the table. In this case, the motor controller 18 generates a motor drive command for relatively moving the tool so that the machining operation specified by the machining program is performed.

The switching control unit 20 switches and controls the inverse converter 16. That is, the switching control unit 20 switches and controls the switching element 16a of the inverse converter 16 based on the motor drive command output from the motor controller 18, the feedback signal of the rotation position output from the motor M, and the like. To generate a PWM control signal for. When the switching control unit 20 generates a PWM control signal, the switching control unit 20 outputs the generated PWM control signal to the inverse converter 16. By switching the switching element 16a based on this PWM control signal, the inverse converter 16 converts the capacitor voltage stored in the smoothing capacitor 14 into a three-phase AC voltage.

In addition to the above components, the motor drive device 10 includes a switch 30, a sensor 32, a DC voltage detection unit 34, a control unit 36, an abnormality detection unit 38, and a notification unit 40 as components.

The switch 30 can switch between a supply state in which the three-phase AC voltage supplied from the three-phase AC power supply P is supplied to the rectifier 12 and a cutoff state in which the supply of the three-phase AC voltage to the rectifier 12 is cut off. Yes, it is provided between the three-phase AC power supply P and the rectifier 12. In the present embodiment, the supply state and the cutoff state are switched by the control unit 36. A reactor L is provided in each of the R-phase, S-phase, and T-phase electric circuits connecting the three-phase AC power supply P and the switch 30.

The sensor 32 detects the phase current value flowing from the three-phase AC power supply P to the rectifier 12. In the present embodiment, the sensor 32 detects each phase current value of the R phase, the S phase, and the T phase flowing between the switch 30 and the rectifier 12, and determines each detected phase current value by the control unit 36. Output to.

The DC voltage detection unit 34 detects the voltage value of the capacitor voltage stored in the smoothing capacitor 14, and outputs the voltage value of the detected capacitor voltage to the control unit 36.

The control unit 36 controls the rectifier 12 and the switch 30, and has an initial charge mode in which charging is executed from the time the power is turned on until the drive voltage of the motor M is obtained, and a power off state after the drive voltage is obtained. It has a normal charging mode that executes charging until it becomes.

The control unit 36 executes the initial charge mode, for example, when a power-on command is given from the outside. In the initial charge mode, the control unit 36 switches the switch 30 from the cutoff state to the supply state, and does not switch control the switching element 12a of the rectifier 12. Therefore, the AC voltage supplied from the three-phase AC power supply P to the rectifier 12 via the switch 30 is converted into a DC voltage by diode rectification. Therefore, in the initial charge mode, the smoothing capacitor 14 is charged based on the DC voltage converted by diode rectification.

The control unit 36 monitors the amount of storage accumulated in the smoothing capacitor 14 by charging based on diode rectification based on the voltage value of the capacitor voltage given by the DC voltage detection unit 34. When the voltage value of the capacitor voltage given by the DC voltage detection unit 34 exceeds a predetermined voltage threshold value, the control unit 36 transitions from the initial charge mode to the normal charge mode.

In the normal charging mode, the control unit 36 controls switching of the switching element 12a of the rectifier 12 while the switch 30 is maintained in the supply state. That is, the control unit 36 calculates the current command value (DQ coordinate system) based on the deviation between the voltage command value output from the motor controller 18 and the voltage value of the capacitor voltage output from the DC voltage detection unit 34. .. Further, the control unit 36 converts the three-phase phase current values output from the sensor 32 into the DQ coordinate system, and obtains the feedback value converted into the DQ coordinate system. The conversion to the DQ coordinate system is a conversion from a 3-phase to a 2-phase stationary coordinate system, and the converted 2-phase stationary coordinate system is converted into a rotating coordinate system that rotates in synchronization with the rotating magnetic field of the motor M. be. The control unit 36 generates a PWM control signal for switching control of the switching element 12a of the rectifier 12 based on the deviation between the current command value converted into the DQ coordinate system and the feedback value, and the generated PWM control signal is used as the rectifier. Output to 12. By switching the switching element 12a based on this PWM control signal, the rectifier 12 converts the AC voltage supplied from the three-phase AC power supply P into a DC voltage. Therefore, in the normal charging mode, the smoothing capacitor 14 is charged based on the DC voltage converted by the switching of the switching element 12a.

Further, in the normal charging mode, the control unit 36 has an abnormality in the current command value calculated based on the deviation between the voltage command value output from the motor controller 18 and the voltage value of the capacitor voltage output from the DC voltage detection unit 34. Output to the detection unit 38. Since the control unit 36 does not perform switching control of the switching element 12a of the rectifier 12 as described above in the initial charge mode, the control unit 36 does not calculate the current command value. Therefore, the control unit 36 does not output the current command value to the abnormality detection unit 38 when the initial charge mode is being executed.

Here, when an abnormality of the sensor 32 is detected by the abnormality detecting unit 38, an abnormality signal is given to the control unit 36 from the abnormality detecting unit 38. In this case, the control unit 36 executes the charging process, but the processing content differs depending on the time when the abnormality of the sensor 32 is detected.

That is, when the abnormality of the sensor 32 is detected during the execution of the initial charging mode, the control unit 36 immediately stops the charging of the smoothing capacitor 14. Specifically, when an abnormality signal is given from the abnormality detection unit 38 while the initial charge mode is being executed, the control unit 36 switches the switch 30 from the supply state to the cutoff state by diode rectification of the rectifier 12. The charging of the smoothing capacitor 14 is stopped.

On the other hand, when an abnormality of the sensor 32 is detected during the execution of the normal charging mode, the motor M can be driven using the capacitor voltage stored in the smoothing capacitor 14 as the driving voltage. Therefore, when the charging of the smoothing capacitor 14 is stopped and the motor M cannot be driven, the member moved by the driving of the motor M becomes uncontrollable and coasts or stops. As described above, this member may coast or coast, regardless of whether it is a table on which the object to be machined is placed or a tool for machining the object to be machined. By stopping, the tool and the object to be machined may remain in contact with each other. In this state, the tool may be damaged or processing defects may occur.

Therefore, when an abnormality of the sensor 32 is detected during the execution of the normal charging mode, the control unit 36 determines the charging stop timing of the smoothing capacitor 14 depending on whether or not the motor M is in the driven state. change.

Specifically, the control unit 36 inquires whether or not the three-phase AC power supply P may be cut off when an abnormality signal is given from the abnormality detection unit 38 while the normal charging mode is being executed. A signal is generated, and the generated inquiry signal is output to the motor controller 18. Here, when the motor M is in the non-driving state, a response signal indicating that the three-phase AC power supply P may be cut off is given from the motor controller 18 as a response to the inquiry signal. In this case, the control unit 36 stops the charging of the smoothing capacitor 14 by switching the switch 30 from the supply state to the cutoff state.

On the other hand, when the motor M is in the driving state, a response signal indicating that the three-phase AC power supply P should be shut off is given from the motor controller 18 as a response to the inquiry signal. In this case, the motor controller 18 generates a motor drive command for relatively moving the table so as to perform a protective operation to move to a predetermined retracted position, and outputs the motor drive command to the switching control unit 20. Further, when the operation completion signal indicating that the protection operation is completed is given from the switching control unit 20, the motor controller 18 outputs a response signal indicating that the three-phase AC power supply P may be cut off to the control unit 36. do. The control unit 36 switches the switch 30 from the supply state to the cutoff state when this response signal is given.

In this way, when an abnormality occurs in the sensor 32 when the motor M is driven in the normal charging mode, switching rectification is switched to diode rectification, and charging of the smoothing capacitor 14 by diode rectification is maintained until the protection operation is completed. Ru. In this case, charging of the smoothing capacitor 14 is stopped after the protection operation is completed.

The abnormality detection unit 38 detects an abnormality in the sensor 32. As described above, when the control unit 36 is executing the initial mode, the current command value is not output to the abnormality detection unit 38. In this case, the abnormality detection unit 38 compares each of the three-phase phase current values (amplitude) output from the sensor 32 with the amplitude threshold value. The anomaly detection unit 38 is at least one phase when all of the three-phase phase current values (amplitude) do not exceed the amplitude threshold, or after all of the three-phase phase current values (amplitude) exceed the amplitude threshold. When the phase current value (amplitude) of is lower than the amplitude threshold value, an abnormality of the sensor 32 is detected.

On the other hand, when the control unit 36 is executing the normal mode, the current command value is output from the control unit 36 to the abnormality detection unit 38 as described above. In this case, the abnormality detection unit 38 converts the three-phase phase current value output from the sensor 32 into the DQ coordinate system, the feedback value converted into the DQ coordinate system, and the current command output from the control unit 36. The deviation from the value is compared with a given deviation threshold. When the state in which the deviation between the current command value and the feedback value exceeds the deviation threshold value continues for a predetermined period, the abnormality detection unit 38 detects the abnormality of the sensor 32.

When the abnormality detection unit 38 detects the abnormality of the sensor 32, it generates an abnormality signal indicating that the abnormality of the sensor 32 is detected, and outputs the generated abnormality signal to both the control unit 36 and the notification unit 40.

The notification unit 40 notifies that the sensor 32 may have an abnormality. The notification unit 40 starts notification when an abnormality signal is given from the abnormality detection unit 38. Specific examples of the notification method include a display method for displaying on a display, a sound generation method for generating a warning sound from an acoustic generator, a light generation method for generating light from a lamp such as a warning lamp, and the like. In addition, two or more notification methods may be used. Further, the display, the sound generator or the lamp may be provided in the notification unit 40 or may be provided outside.

Next, a control method of the motor drive device 10 will be described. FIG. 2 is a flowchart showing a processing procedure of the initial charge processing from the power-off state to obtaining the drive voltage of the motor M.

For example, when a power-on command is given from the outside, in step S1, the control unit 36 switches the switch 30 from the cutoff state to the supply state to start charging the smoothing capacitor 14 by diode rectification of the rectifier 12. Proceed to step S2. In step S2, the abnormality detection unit 38 starts monitoring the abnormality of the sensor 32 by comparing each of the three-phase phase current values (amplitudes) output from the sensor 32 with a predetermined amplitude threshold value.

Here, when all of the phase current values (amplitude) exceed the amplitude threshold value, it means that all of the sensors 32 are operating normally. In this case, the abnormality detection unit 38 proceeds to step S3 and continues to monitor the abnormality of the sensor 32. Here, when none of the three-phase phase current values (amplitude) output from the sensor 32 is below the amplitude threshold value, it means that the normally operating sensor 32 continues to operate normally. In this case, the abnormality detection unit 38 continues to monitor the abnormality of the sensor 32 and proceeds to step S4. In step S4, the control unit 36 compares the voltage value of the capacitor voltage output from the DC voltage detection unit 34 with a predetermined voltage threshold value, and a smoothing capacitor by diode rectification of the rectifier 12 until the voltage value exceeds the voltage threshold value. Continue charging 14. When the voltage value of the capacitor voltage exceeds the voltage threshold value, in step S5, the control unit 36 starts switching control of the switching element 12a of the rectifier 12 while maintaining the switch 30 in the supply state. As a result, the initial charge process is completed.

On the other hand, when all of the three-phase phase current values (amplitude) do not exceed the amplitude threshold value (step S2), or after all of the three-phase phase current values (amplitude) exceed the amplitude threshold value, at least one phase. If the amplitude threshold is below (step S3), it means that at least one of the sensors 32 is abnormal. In this case, the abnormality detection unit 38 generates an abnormality signal, outputs the abnormality signal to the notification unit 40 and the control unit 36, and proceeds to step S6. In step S6, the notification unit 40 notifies that the sensor 32 may be abnormal. The control unit 36 stops the charging of the smoothing capacitor 14 by the diode rectification of the rectifier 12 by switching the switch 30 from the supply state to the cutoff state. As a result, the initial charge process is completed.

As described above, in the initial charging process, the smoothing capacitor 14 is charged by the diode rectification of the rectifier 12 until the capacitor voltage of the smoothing capacitor 14 exceeds the voltage threshold. Further, in the initial charging process, if an abnormality of the sensor 32 is detected before the capacitor voltage exceeds the voltage threshold value, charging of the smoothing capacitor 14 is stopped and there is a possibility that the abnormality has occurred. Is notified.

Next, the charging process after the initial charging process will be described. FIG. 3 is a flowchart showing a processing procedure of the charging process after the initial charging process. However, in FIG. 3, it is assumed that the motor M is in the driving state.

In step S11, the control unit 36 continues the switching control of the switching element 12a of the rectifier 12 while maintaining the switch 30 in the supply state, and proceeds to step S12.

In step S12, the abnormality detection unit 38 compares the deviation between the current command value output from the control unit 36 and the feedback value converted into the DQ coordinate system output from the sensor 32 with a predetermined deviation threshold value. , Monitor the abnormality of the sensor 32.

Here, if the state in which the deviation between the current command value and the feedback value exceeds the deviation threshold value does not continue for a predetermined period, the abnormality detection unit 38 continues to monitor the abnormality of the sensor 32. In this case, the control unit 36 returns to step S11 and continues the switching control of the switching element 12a.

On the other hand, when the state in which the deviation between the current command value and the feedback value exceeds the deviation threshold value continues for a predetermined period, the abnormality detection unit 38 detects the abnormality of the sensor 32. In this case, the abnormality detection unit 38 generates an abnormality signal, outputs the abnormality signal to the notification unit 40 and the control unit 36, and proceeds to step S13.

In step S13, the notification unit 40 notifies that the sensor 32 may be abnormal. By stopping the switching control while the switch 30 is maintained in the supply state, the control unit 36 switches from charging the smoothing capacitor 14 by switching rectification to charging the smoothing capacitor 14 by diode rectification, and proceeds to step S14.

In step S14, the control unit 36 generates an inquiry signal for inquiring whether or not the three-phase AC power supply P may be cut off, and outputs the inquiry signal to the motor controller 18. The motor controller 18 outputs a response signal to the control unit 36 to wait for the three-phase AC power supply P to be cut off, starts a protection operation, and proceeds to step S15.

In step S15, the motor controller 18 waits until an operation completion signal indicating the completion of the protection operation is given from the switching control unit 20. When the operation completion signal is given, the motor controller 18 outputs a response signal indicating that the three-phase AC power supply P may be cut off to the control unit 36, and proceeds to step S16.

In step S16, the control unit 36 stops the charging of the smoothing capacitor 14 by diode rectification by switching the switch 30 from the supply state to the cutoff state. As a result, the normal charging process is completed.

As described above, in the normal charging process, the smoothing capacitor 14 is charged by switching control, and the motor M is driven using the capacitor voltage accumulated by this charging as the driving voltage. When an abnormality of the sensor 32 is detected while driving the motor M, the smoothing capacitor 14 is charged by diode rectification from the occurrence of the abnormality until the protection operation is completed, and smoothing is performed after the protection operation is completed. Charging of the capacitor 14 is stopped.

[Modification example]
Although the above-described embodiment has been described above as an example of the present invention, the technical scope of the present invention is not limited to the scope described in the above-described embodiment. Of course, it is possible to make various changes or improvements to the above embodiments. It is clear from the description of the claims that the form with such changes or improvements may be included in the technical scope of the present invention.

<Modification 1>
In the above embodiment, the sensor 32 detects the phase current value of each of the three phases flowing through the rectifier 12. When the sensor 32 detects, for example, two-phase phase current values, the phase current values of the remaining phases can be calculated using the two-phase phase current values. Therefore, the sensor 32 may detect at least two phase current values.

<Modification 2>
In the above embodiment, the sensor 32 detects the phase current value of each of the three phases flowing through the rectifier 12. However, the sensor 32 may detect at least two phase voltage values. When the sensor 32 detects the phase voltage value, if the abnormality detection unit 38 calculates the phase current value from the phase voltage value detected by the sensor 32, the calculated phase current value is used in the same manner as in the above embodiment. The abnormality of the sensor 32 can be detected.

<Modification 3>
The above-described embodiment and the above-mentioned modification may be arbitrarily combined as long as there is no contradiction.

[Technical Thought]
The technical ideas that can be grasped from the above-described embodiments and modifications are described below.

<First technical idea>
The motor drive device (10) drives the motor (M) using a three-phase AC power supply (P). The motor drive device (10) includes a rectifier (12), a smoothing capacitor (14), an inverse converter (16), a sensor (32), an abnormality detection unit (38), and a control unit (36).

The rectifier (12) has a plurality of switching elements (12a) and a diode (12b) connected in parallel to each switching element (12a), and is supplied from a three-phase AC power supply (P). Converts AC voltage to DC voltage. The smoothing capacitor (14) is connected to the DC side of the rectifier (12). The inverse converter (16) reversely converts the capacitor voltage stored in the smoothing capacitor (14) into a three-phase AC voltage, and drives the motor (M) using the inversely converted three-phase AC voltage as a drive voltage. The sensor (32) detects at least two phase current values or phase voltage values flowing through the rectifier (12). The abnormality detection unit (38) detects an abnormality in the sensor (32). The control unit (36) switches and controls the switching element (12a) to charge the smoothing capacitor (14), and is an abnormality of the sensor (32) when the motor (M) is driven. When this occurs, the switching control is stopped and the smoothing capacitor (14) is charged by the diode rectification of the rectifier (12).

In such a motor drive device (10), even if switching control is stopped when an abnormality occurs in the sensor (32) while driving the motor (M), the smoothing capacitor (14) is generated by diode rectification of the rectifier (12). It will be charged. As a result, the inverse converter (16) can continue to output the AC voltage, and the motor (M) moves the table on which the object to be machined is placed and the tool for machining the object to be machined relative to each other. In the case of a motor, it is possible to drive the motor (M) to move at least one of the table and the tool to the retracted position. Therefore, it is possible to prevent the tool from being damaged or processing defects when the sensor (32) is detected for abnormality.

The abnormality detection unit (38) is a sensor (32) when the deviation between the feedback value converted into the DQ coordinate system based on the phase current value or the phase voltage value and the current command value exceeds a predetermined deviation threshold value. The abnormality may be detected. It becomes easier to accurately detect the abnormality of the sensor (32) as compared with the case of detecting the abnormality of the sensor (32) based on other than the deviation.

The abnormality detection unit (38) may detect an abnormality in the sensor (32) when the state in which the deviation exceeds the deviation threshold value continues for a predetermined period. As a result, it is possible to prevent the sensor (32) from being detected as abnormal when the state in which the deviation exceeds the deviation threshold value is transient.

The motor drive device (10) is a switch (30) capable of switching between a supply state in which the three-phase AC voltage is supplied to the rectifier (12) and a cutoff state in which the supply of the three-phase AC voltage to the rectifier (12) is cut off. The control unit (36) may stop the switching control while maintaining the switch (30) in the supply state when a sensor abnormality occurs during driving. As a result, when an abnormality occurs in the sensor (32) when the motor (M) is driven, the smoothing capacitor (14) can be reliably charged by the diode rectification of the rectifier (12).

The control unit (36) maintains the switch (30) in the supply state until the protection operation for protecting the member moved by the drive of the motor (M) is completed after the sensor abnormality occurs during driving, and the protection operation is performed. The switch (30) may be switched to the shutoff state after the completion of. As a result, the operator can be made to inspect the sensor (32) immediately after the protection operation is completed.

The control unit (36) switches the switch (30) from the cutoff state to the supply state to start charging the smoothing capacitor (14). In that case, the switch (30) may be switched to the cutoff state to stop the charging of the smoothing capacitor (14). As a result, the operator can be made to inspect the sensor (32) immediately after the abnormality occurs.

The abnormality detection unit (38) is a sensor (32) when the phase current value of at least one phase falls below the amplitude threshold value after the phase current value of at least two phases exceeds a predetermined amplitude threshold value at the time of initial charging. The abnormality may be detected. As a result, it is possible to detect an abnormality in the sensor (32) even if the rectifier (12) is not controlled for switching.

The control unit (36) maintains the switch (30) in the supply state when the initial sensor abnormality does not occur until the capacitor voltage stored in the smoothing capacitor (14) exceeds a predetermined voltage threshold value. However, the switching control may be started. As a result, switching control can be executed in a stable state.

<Second technical idea>
The control method is a control method for a motor drive device (10) that drives a motor (M) using a three-phase AC power supply (P). The motor drive device (10) includes a rectifier (12), a smoothing capacitor (14), an inverse converter (16), and a sensor (32). The rectifier (12) has a plurality of switching elements (12a) and a diode (12b) connected in parallel to each switching element (12a), and is supplied from a three-phase AC power supply (P). Converts AC voltage to DC voltage. The smoothing capacitor (14) is connected to the DC side of the rectifier (12). The inverse converter (16) reversely converts the capacitor voltage stored in the smoothing capacitor (14) into a three-phase AC voltage, and drives the motor (M) using the inversely converted three-phase AC voltage as a drive voltage. The sensor (32) detects at least two phase current values or phase voltage values flowing through the rectifier (12).

The control method includes an initial charging step (S3) in which the smoothing capacitor (14) is charged by diode rectification of the rectifier (12) from the start of supply of the three-phase AC voltage until the capacitor voltage reaches a predetermined voltage value. A charging step (S11) in which the switching element (12a) is switched and controlled to charge the smoothing capacitor (14), an abnormality detection step (S12) for detecting an abnormality in the sensor (32), and a motor (M) are being driven. It has a control step (S13) for stopping the switching control and charging the smoothing capacitor (14) by the diode rectification of the rectifier (12) when the driving sensor abnormality, which is an abnormality of the sensor (32), occurs.

In such a control method, the smoothing capacitor (14) is charged by the diode rectification of the rectifier (12) even if the switching control is stopped when an abnormality occurs in the sensor (32) when the motor (M) is driven. As a result, the inverse converter (16) can continue to output the AC voltage, and the motor (M) moves the table on which the object to be machined is placed and the tool for machining the object to be machined relative to each other. In the case of a motor, it is possible to drive the motor (M) to move at least one of the table and the tool to the retracted position. Therefore, it is possible to prevent the tool from being damaged or processing defects when the sensor (32) is detected for abnormality.

In the abnormality detection step (S12), when the deviation between the feedback value converted into the DQ coordinate system based on the phase current value or the phase voltage value and the current command value exceeds a predetermined deviation threshold value, the sensor (32) is used. The abnormality may be detected. It becomes easier to accurately detect the abnormality of the sensor (32) as compared with the case of detecting the abnormality of the sensor (32) based on other than the deviation.

The abnormality detection step (S12) may detect an abnormality in the sensor (32) when the state in which the deviation exceeds the deviation threshold value continues for a predetermined period. As a result, it is possible to prevent the sensor (32) from being detected as abnormal when the state in which the deviation exceeds the deviation threshold value is transient.

The motor drive device (10) is a switch (30) capable of switching between a supply state in which the three-phase AC voltage is supplied to the rectifier (12) and a cutoff state in which the supply of the three-phase AC voltage to the rectifier (12) is cut off. The control step may stop the switching control while maintaining the switch (30) in the supply state when a sensor abnormality occurs during driving. As a result, when an abnormality occurs in the sensor (32) when the motor (M) is driven, the smoothing capacitor (14) can be reliably charged by the diode rectification of the rectifier (12).

The control method is to maintain the switch (30) in the supply state until the protection operation for protecting the member moved by the drive of the motor (M) is completed after the sensor abnormality occurs during driving, and the protection operation is completed. After that, the switch (30) may be provided with a shutoff step (S15) for switching to the shutoff state. As a result, the operator can be made to inspect the sensor (32) immediately after the protection operation is completed.

The control method is to switch the switch (30) from the cutoff state to the supply state and start charging the smoothing capacitor (14). The switch (30) may be switched to the cutoff state to have an initial control step (S6) for stopping the charging of the smoothing capacitor (14). As a result, the operator can be made to inspect the sensor (32) immediately after the abnormality occurs.

The control method is an initial time to detect an abnormality of the sensor (32) when the phase current value of at least one phase falls below the amplitude threshold value after the phase current value of at least two phases exceeds a predetermined amplitude threshold value. It may have an abnormality detection step (S3). As a result, it is possible to detect an abnormality in the sensor (32) even if the rectifier (12) is not controlled for switching.

As a control method, if an initial sensor abnormality does not occur before the capacitor voltage stored in the smoothing capacitor (14) exceeds the voltage threshold value, switching control is started while maintaining the switch (30) in the supply state. It may have a start step (S5) to be performed. As a result, switching control can be executed in a stable state.

10 ... Motor drive device 12 ... Rectifier 14 ... Smoothing capacitor 16 ... Reverse converter 18 ... Motor controller 20 ... Switching control unit 30 ... Switch 32 ... Sensor 34 ... DC voltage detection unit 36 ... Control unit 38 ... Abnormality detection unit 40 ... Notification unit M ... Motor

Claims (16)

A motor drive device that drives a motor using a three-phase AC power supply.
A rectifier having a plurality of switching elements and a diode connected in parallel to each of the switching elements and converting a three-phase AC voltage supplied from the three-phase AC power supply into a DC voltage.
A smoothing capacitor connected to the DC side of the rectifier,
A reverse converter that reversely converts the capacitor voltage stored in the smoothing capacitor to the three-phase AC voltage and drives the motor using the reversely converted three-phase AC voltage as a drive voltage.
A sensor that detects at least two phase current values or phase voltage values flowing through the rectifier,
An abnormality detection unit that detects an abnormality in the sensor,
The switching element is switched and controlled to charge the smoothing capacitor. When the sensor abnormality occurs during driving, which is an abnormality of the sensor when the motor is driven, the switching control is stopped and the rectifier is used. A control unit that charges the smoothing capacitor by diode rectification,
A motor drive device. The motor driving device according to claim 1.
The abnormality detection unit detects an abnormality in the sensor when the deviation between the feedback value converted into the DQ coordinate system based on the phase current value or the phase voltage value and the current command value exceeds a predetermined deviation threshold value. Motor drive to detect. The motor driving device according to claim 2.
The abnormality detection unit is a motor drive device that detects an abnormality in the sensor when the deviation exceeds the deviation threshold value for a predetermined period of time. The motor driving device according to any one of claims 1 to 3.
A switch capable of switching between a supply state in which the three-phase AC voltage is supplied to the rectifier and a cutoff state in which the supply of the three-phase AC voltage to the rectifier is cut off is provided.
The control unit is a motor drive device that stops the switching control while maintaining the switch in the supply state when the driving sensor abnormality occurs. The motor driving device according to claim 4.
The control unit maintains the switch in the supply state from the occurrence of the drive sensor abnormality until the protection operation for protecting the member moved by the drive of the motor is completed, and the protection operation is completed. A motor drive device that subsequently switches the switch to the shutoff state. The motor driving device according to claim 4 or 5.
The control unit switches the switch from the shutoff state to the supply state and starts charging the smoothing capacitor. When the sensor abnormality occurs at the time of initial charging, which is an abnormality of the sensor, the control unit opens / closes the switch. A motor drive device that switches the device to the cutoff state and stops charging of the smoothing capacitor. The motor driving device according to claim 6.
The abnormality detection unit is the sensor when the phase current value of at least one phase falls below the amplitude threshold value after the phase current value of at least two phases exceeds a predetermined amplitude threshold value during the initial charging. Motor drive device that detects abnormalities in the motor. The motor driving device according to claim 6.
When the initial sensor abnormality does not occur until the capacitor voltage stored in the smoothing capacitor exceeds a predetermined voltage threshold, the control unit switches the switch while maintaining the switch in the supply state. A motor drive that initiates control. It is a control method of a motor drive device that drives a motor using a three-phase AC power supply.
The motor drive device is
A rectifier having a plurality of switching elements and a diode connected in parallel to each of the switching elements and converting a three-phase AC voltage supplied from the three-phase AC power supply into a DC voltage.
A smoothing capacitor connected to the DC side of the rectifier,
A reverse converter that reverse-converts the capacitor voltage stored in the smoothing capacitor to the three-phase AC voltage and applies the reverse-converted three-phase AC voltage to the motor as a drive voltage.
A sensor that detects at least two phase current values or phase voltage values flowing through the rectifier,
Equipped with
An initial charging step of charging the smoothing capacitor by diode rectification of the rectifier from the start of supply of the three-phase AC voltage until the capacitor voltage reaches a predetermined voltage value.
A charging step in which the switching element is switched and controlled to charge the smoothing capacitor,
An abnormality detection step for detecting an abnormality in the sensor, and
A control step of stopping the switching control and charging the smoothing capacitor by diode rectification of the rectifier when a sensor abnormality during driving, which is an abnormality of the sensor during driving of the motor, occurs.
How to control a motor drive with. The control method for a motor drive device according to claim 9.
The abnormality detection step detects an abnormality in the sensor when the deviation between the feedback value converted into the DQ coordinate system based on the phase current value or the phase voltage value and the current command value exceeds a predetermined deviation threshold value. A method of controlling the motor drive to detect. The control method for a motor drive device according to claim 10.
The abnormality detection step is a control method for a motor drive device that detects an abnormality in the sensor when the deviation exceeds the deviation threshold value for a predetermined period of time. The method for controlling a motor drive device according to any one of claims 9 to 11.
The motor drive device includes a switch capable of switching between a supply state in which the three-phase AC voltage is supplied to the rectifier and a cutoff state in which the supply of the three-phase AC voltage to the rectifier is cut off.
The control step is a control method for a motor drive device, which stops the switching control while maintaining the switch in the supply state when the driving sensor abnormality occurs. The control method for a motor drive device according to claim 12.
The switch is maintained in the supply state from the occurrence of the drive sensor abnormality until the protection operation for protecting the member moved by the drive of the motor is completed, and after the protection operation is completed, the switch is operated. A method for controlling a motor drive device, comprising a shutoff step for switching to the shutoff state. The method for controlling a motor drive device according to claim 12 or 13.
When the initial sensor abnormality, which is an abnormality of the sensor at the time of initial charging in which the switch is switched from the cutoff state to the supply state and the charging of the smoothing capacitor is started, the switch is brought into the cutoff state. A method for controlling a motor drive device, which comprises an initial control step of switching to and stopping charging of the smoothing capacitor. The control method for a motor drive device according to claim 14.
It has an initial abnormality detection step of detecting an abnormality of the sensor when the phase current value of at least one phase falls below the amplitude threshold value after the phase current value of at least two phases exceeds a predetermined amplitude threshold value. , How to control the motor drive. The control method for a motor drive device according to claim 14.
If the initial sensor abnormality does not occur until the capacitor voltage stored in the smoothing capacitor exceeds a predetermined voltage threshold value, the switching control is started while maintaining the switch in the supply state. A method of controlling a motor drive with steps.

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