JP2020036509A - Motor drive device and control method of the same - Google Patents

Abstract

To prevent a tool from being damaged or a machining defect from occurring when a sensor abnormality is detected.SOLUTION: A motor drive device 10 has a control unit 36 for controlling switching of a switching element 12a of a rectifier 12 to charge a smoothing capacitor 14. When an abnormality detecting unit 38 detects abnormality of a sensor 32 during driving of a motor M, the control unit 36 stops switching control and charges the smoothing capacitor 14 by diode rectification of the rectifier 12.SELECTED DRAWING: Figure 1

Description

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

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

  Patent Document 1 below discloses a sensor that detects a phase current flowing through each of the three phases, an adder that calculates the sum of the respective phase currents detected by the sensors, and a sum of the phase currents calculated by the adder. An apparatus for detecting abnormality of a motor including a comparator for comparing a motor with a predetermined value is disclosed. In this abnormality detection device, an abnormality of the sensor is detected when the sum of the phase currents exceeds a predetermined value. In this case, in the abnormality detection device, the supply of power from the power supply is interrupted by shutting off the contactor provided between the power supply and the power module.

JP-A-6-253585

  However, if the contactor is shut off when a sensor abnormality is detected, the supply of AC power from the three-phase AC power supply to the rectifier is stopped, and the inverter outputs AC power for driving the motor. Since it becomes impossible, the normal operation of the motor cannot be continued. Therefore, when the motor is a motor for relatively moving the table on which the workpiece is mounted and the tool for processing the workpiece, when an abnormality of the sensor is detected during the processing, the workpiece is The control may not be possible while the tool and the tool are in contact with each other. For this reason, there is a concern that breakage of the tool or machining failure may occur.

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

  A first aspect of the present invention is a motor driving device that drives a motor using a three-phase AC power supply, including a plurality of switching elements and a diode connected in parallel to each of the switching elements, A rectifier for 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, and a capacitor voltage stored in the smoothing capacitor being converted to the three-phase AC voltage. An inverter that drives the motor using the inverted three-phase AC voltage as a drive voltage, a sensor that detects at least two-phase current or phase voltage flowing through the rectifier, and the sensor An abnormality detection unit that detects abnormality of the motor, and controls the switching of the switching element to charge the smoothing capacitor. If abnormalities definitive abnormal is driven when the sensor of the sensor has occurred stops the switching control, and a control unit for charging the smoothing capacitor by the diode rectification of the rectifier.

  A second aspect of the present invention is a method for controlling a motor driving device that drives a motor using a three-phase AC power supply, wherein the motor driving device includes a plurality of switching elements and a parallel connection to each of the switching elements. A rectifier that converts 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, and a diode that is stored in the smoothing capacitor. An inverter that converts the capacitor voltage to the three-phase AC voltage and converts the inverted three-phase AC voltage to the motor as a drive voltage, and a phase current value or a phase voltage value of at least two phases flowing through the rectifier. And a sensor for detecting the diode voltage of the rectifier after the supply of the three-phase AC voltage is started until the capacitor voltage reaches a predetermined voltage value. An initial charging step of charging the smoothing capacitor, a charging step of controlling the switching element to charge the smoothing capacitor, an abnormality detecting step of detecting an abnormality of the sensor, and the sensor at the time of driving the motor. And a control step of stopping the switching control and charging the smoothing capacitor by diode rectification of the rectifier when a drive-time sensor abnormality that is an abnormality occurs.

  According to the present invention, even when the switching control is stopped when an abnormality occurs in the sensor during driving of the motor, the smoothing capacitor is charged by diode rectification of the rectifier, and the inverter can output AC power for driving the motor. With this, when the motor is a motor for relatively moving the table on which the workpiece is placed and the tool for processing the workpiece, at least one of the table and the tool is moved to the retracted position. It becomes possible to drive the motor. Therefore, it is possible to prevent the tool from being damaged or the processing from being defective.

1 is a schematic diagram illustrating a configuration of a motor drive device according to an embodiment. 6 is a flowchart illustrating a procedure of an initial charging process from a power-off state to obtaining a motor driving voltage. It is a flowchart which shows the processing procedure of a charging process after an initial charging process.

  BEST MODE FOR CARRYING OUT THE INVENTION 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 showing preferred embodiments.

[Embodiment]
FIG. 1 is a schematic diagram illustrating a configuration of a motor driving device 10 according to the embodiment. The motor driving device 10 drives the motor M using the three-phase AC power supply P, and includes a rectifier 12, a smoothing capacitor 14, an inverter 16, a motor controller 18, and a switching controller 20 as constituent elements.

  The rectifier 12 converts a 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. Having. Examples of the switching element 12a include an IGBT, a power MOSFET, a bipolar transistor, and a thyristor. 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. When the smoothing capacitor 14 is charged, a capacitor voltage is accumulated in the smoothing capacitor 14.

  The inverter 16 converts the capacitor voltage stored in the smoothing capacitor 14 into a three-phase AC voltage, and outputs the converted three-phase AC voltage to drive the motor M. Like the rectifier 12, the inverter 16 includes 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 a table on which the workpiece is mounted with respect to a tool for processing the workpiece. 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. Note that the motor M may be a motor for relatively moving the tool with respect 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 controls switching of the inverter 16. That is, the switching control unit 20 controls the switching of the switching element 16a of the inverter 16 based on the motor drive command output from the motor controller 18, the feedback signal of the rotational position output from the motor M, and the like. For generating a PWM control signal. Upon generating the PWM control signal, the switching control unit 20 outputs the generated PWM control signal to the inverter 16. When the switching element 16a switches based on the PWM control signal, the inverter 16 converts the capacitor voltage stored in the smoothing capacitor 14 into a three-phase AC voltage.

  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 in addition to the above 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, provided between the three-phase AC power supply P and the rectifier 12. In the present embodiment, the control unit 36 switches between the supply state and the cutoff state. A reactor L is provided in each of the R-phase, S-phase, and T-phase electric paths connecting the three-phase AC power supply P and the switch 30.

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

  The control unit 36 controls the rectifier 12 and the switch 30. The control unit 36 performs an initial charging mode in which charging is performed from when the power is turned on until a driving voltage of the motor M is obtained, and a power-off state after the driving voltage is obtained. And a normal charging mode in which the charging is performed until the charging time is reached.

  The control unit 36 executes the initial charging mode when, for example, a power-on command is given from the outside. In the initial charging mode, the control unit 36 switches the switch 30 from the cut-off state to the supply state, and does not control the switching of the switching element 12a of the rectifier 12. Therefore, an 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 charging mode, the smoothing capacitor 14 is charged based on the DC voltage converted by the diode rectification.

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

  In the normal charging mode, the control unit 36 controls the switching of the switching element 12a of the rectifier 12 while keeping the switch 30 in the supply state. That is, control unit 36 calculates a current command value (DQ coordinate system) based on a deviation between the voltage command value output from motor controller 18 and the voltage value of the capacitor voltage output from DC voltage detection unit 34. . Further, the control unit 36 converts the three-phase current values output from the sensor 32 into a DQ coordinate system, and obtains a feedback value converted into the DQ coordinate system. The conversion to the DQ coordinate system is performed by converting a three-phase stationary coordinate system into a two-phase stationary coordinate system, and converting the converted two-phase stationary coordinate system into a rotating coordinate system that rotates in synchronization with the rotating magnetic field of the motor M. is there. The control unit 36 generates a PWM control signal for controlling the switching 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 converts the generated PWM control signal into a rectifier. 12 is output. The rectifier 12 converts the AC voltage supplied from the three-phase AC power supply P into a DC voltage by the switching element 12a switching based on the PWM control signal. 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 abnormally outputs 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. In the initial charging mode, the control unit 36 does not calculate the current command value because the switching of the switching element 12a of the rectifier 12 is not controlled as described above. Therefore, the control unit 36 does not output the current command value to the abnormality detection unit 38 when executing the initial charging mode.

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

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

  On the other hand, when the 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 accumulated in the smoothing capacitor 14 as a driving voltage. For this reason, when the charging of the smoothing capacitor 14 is stopped and the motor M cannot be driven, the members that are moved by the drive of the motor M become uncontrollable and coast or stop. This member, as described above, is a table on which the workpiece is placed, or whether the tool is a tool that processes the workpiece, whether the member is coasting, or By stopping, the tool and the workpiece may be kept in contact with each other. In this state, breakage of the tool or processing failure may occur.

  Therefore, when the abnormality of the sensor 32 is detected during the execution of the normal charging mode, the control unit 36 sets the timing of stopping the charging of the smoothing capacitor 14 according to whether the motor M is in a driven state. Change.

  Specifically, when an abnormality signal is given from abnormality detection unit 38 during execution of the normal charging mode, control unit 36 inquires whether or not to shut off three-phase AC power supply P. 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-drive state, a response signal indicating that the three-phase AC power supply P may be shut down is provided from the motor controller 18 as a response to the inquiry signal. In this case, the control unit 36 stops charging 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 provided 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 protection operation to move the table to a predetermined retreat position, and outputs the motor drive command to the switching control unit 20. When an operation completion signal indicating that the protection operation has been 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. I do. The control unit 36 switches the switch 30 from the supply state to the cutoff state when the response signal is given.

  As described above, when an abnormality occurs in the sensor 32 at the time of driving the motor M in the normal charging mode, switching from switching rectification to diode rectification is performed, and charging of the smoothing capacitor 14 by diode rectification is maintained until the protection operation is completed. You. In this case, charging of the smoothing capacitor 14 is stopped after the protection operation is completed.

  The abnormality detector 38 detects an abnormality of 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 current values (amplitude) output from the sensor 32 with an amplitude threshold. The abnormality detecting unit 38 determines whether at least one of the three phase current values (amplitude) does not exceed the amplitude threshold value or at least one phase current value after all of the three phase current values (amplitude) exceed the amplitude threshold value. When the phase current value (amplitude) falls below 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 current values output from the sensor 32 into a DQ coordinate system, and outputs 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 predetermined deviation threshold. When the state in which the deviation between the current command value and the feedback value exceeds the deviation threshold continues for a predetermined period, the abnormality detection unit 38 detects an abnormality of the sensor 32.

  When detecting the abnormality of the sensor 32, the abnormality detecting unit 38 generates an abnormal signal indicating that the abnormality of the sensor 32 has been detected, and outputs the generated abnormal signal to both the control unit 36 and the notification unit 40.

  The notification unit 40 notifies that there is a possibility that the sensor 32 is abnormal. The notification unit 40 starts notification when an abnormality signal is given from the abnormality detection unit 38. Specific notification methods include, for example, a display method for displaying on a display, a sound generation method for generating a warning sound from a sound generator, and a light generation method for generating light from a lamp such as a warning light. Note that two or more notification methods may be used. In addition, 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 an initial charging process from a power-off state to obtaining a 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 cut-off 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 current values (amplitude) output from the sensor 32 with a predetermined amplitude threshold.

  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, if none of the three-phase current values (amplitude) output from the sensor 32 is lower than the amplitude threshold value, it means that the sensor 32 that is operating normally continues to operate normally. In this case, the abnormality detection unit 38 continues monitoring 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, and until the voltage value exceeds the voltage threshold, the smoothing capacitor by the diode rectification of the rectifier 12. 14 is continued to be charged. 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. Thus, the initial charging process ends.

  On the other hand, if all of the three-phase current values (amplitude) do not exceed the amplitude threshold value (step S2), or if at least one of the three phase current values (amplitude) exceeds the amplitude threshold value, When the amplitude threshold value falls below (step S3), it means that at least one of the sensors 32 is abnormal. In this case, the abnormality detection unit 38 generates and outputs an 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 has a possibility of being abnormal. The control unit 36 stops charging the smoothing capacitor 14 by diode rectification of the rectifier 12 by switching the switch 30 from the supply state to the cutoff state. Thus, the initial charging process ends.

  Thus, 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. In addition, in the initial charging process, if an abnormality of the sensor 32 is detected before the capacitor voltage exceeds the voltage threshold, the charging of the smoothing capacitor 14 is stopped, and the possibility that the abnormality has occurred is detected. Will be notified.

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

  In step S11, the control unit 36 continues the switching control of the switching element 12a of the rectifier 12 while keeping 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. And monitor the sensor 32 for abnormalities.

  Here, when the state in which the deviation between the current command value and the feedback value exceeds the deviation threshold does not continue for a predetermined period, the abnormality detection unit 38 continues to monitor the sensor 32 for abnormality. 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 continues for a predetermined period, the abnormality detection unit 38 detects an abnormality in the sensor 32. In this case, the abnormality detection unit 38 generates an abnormality signal and outputs it 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 has a possibility of being abnormal. The control unit 36 switches the charging of the smoothing capacitor 14 by switching rectification to the charging of the smoothing capacitor 14 by diode rectification by stopping the switching control while maintaining the switch 30 in the supply state, 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 shut off, and outputs the generated inquiry signal to the motor controller 18. The motor controller 18 outputs a response signal to wait for the interruption of the three-phase AC power supply P to the control unit 36, starts the protection operation, and proceeds to step S15.

  In step S15, the motor controller 18 waits until an operation completion signal indicating completion of the protection operation is given from the switching control unit 20. Upon receiving the operation completion signal, the motor controller 18 outputs a response signal indicating that the three-phase AC power supply P may be shut 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. Thus, the normal charging process ends.

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

[Modification]
The above embodiment has been described as an example of the present invention, but the technical scope of the present invention is not limited to the scope described in the above embodiment. It goes without saying that various changes or improvements can be added to the above embodiment. It is apparent from the description of the appended claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

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

<Modification 2>
In the above-described embodiment, the sensor 32 detects each phase current value 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, the abnormality detection unit 38 calculates the phase current value from the phase voltage value detected by the sensor 32, and calculates the phase current value from the calculated phase current value in the same manner as in the above embodiment. An abnormality of the sensor 32 can be detected.

<Modification 3>
The above-described embodiment and the above-described modified examples may be arbitrarily combined within a range where no contradiction occurs.

[Technical thought]
The technical ideas that can be grasped from the above embodiment 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 driving device (10) includes a rectifier (12), a smoothing capacitor (14), an inverter (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 a three-phase power 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 inverter (16) inversely converts the capacitor voltage stored in the smoothing capacitor (14) into a three-phase AC voltage, and drives the motor (M) using the inverted three-phase AC voltage as a driving voltage. The sensor (32) detects at least two phase current values or phase voltage values flowing through the rectifier (12). The abnormality detector (38) detects an abnormality of the sensor (32). The controller (36) controls the switching of the switching element (12a) to charge the smoothing capacitor (14), and is a driving sensor abnormality that is an abnormality of the sensor (32) when the motor (M) is driving. When switching occurs, the switching control is stopped, and the smoothing capacitor (14) is charged by diode rectification of the rectifier (12).

  In such a motor driving device (10), even when the switching control is stopped when an abnormality of the sensor (32) occurs during the driving of the motor (M), the smoothing capacitor (14) is formed by the diode rectification of the rectifier (12). Charged. As a result, the inverter (16) can continue to output the AC voltage, and the motor (M) allows the motor (M) to relatively move the table on which the workpiece is mounted and the tool for processing the workpiece. When a motor is used, the motor (M) can be driven to move at least one of the table and the tool to the retracted position. Therefore, when the sensor (32) detects an abnormality, it is possible to prevent the breakage of the tool and the processing failure from occurring.

  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 detection unit (38) detects the abnormality of the sensor (32). An abnormality may be detected. Compared to the case where the abnormality of the sensor (32) is detected based on other than the deviation, it becomes easier to accurately detect the abnormality of the sensor (32).

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

  The motor drive device (10) is capable of switching between a supply state in which the three-phase AC voltage is supplied to the rectifier (12) and a cut-off 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 the drive-time sensor abnormality occurs. Thus, when an abnormality occurs in the sensor (32) at the time of driving the motor (M), the smoothing capacitor (14) can be reliably charged by diode rectification of the rectifier (12).

  The control unit (36) keeps the switch (30) in the supply state until the protection operation for protecting the member moved by the driving of the motor (M) is completed after the drive-time sensor abnormality occurs, and the protection operation is performed. After the completion of the above, the switch (30) may be switched to the cutoff state. This allows the operator to check the sensor (32) immediately after the protection operation is completed.

  The control unit (36) switches the switch (30) from the cut-off state to the supply state and starts charging the smoothing capacitor (14). In such a case, the switch (30) may be switched to a cutoff state to stop charging the smoothing capacitor (14). This allows the operator to check the sensor (32) immediately after the abnormality has occurred.

  At the time of initial charging, the abnormality detecting unit (38) detects the sensor (32) when at least one phase current value falls below the amplitude threshold after at least two phase current values exceed the predetermined amplitude threshold value. May be detected. Thereby, the abnormality of the sensor (32) can be detected even when the switching control of the rectifier (12) is not performed.

  The control unit (36) maintains the switch (30) in the supply state when the sensor abnormality does not occur at the initial stage until the capacitor voltage accumulated in the smoothing capacitor (14) exceeds a predetermined voltage threshold. Switching control may be started while doing so. Thereby, the switching control can be executed in a stable state.

<Second technical concept>
The control method is a control method of the motor drive device (10) that drives the motor (M) using the three-phase AC power supply (P). The motor driving device (10) includes a rectifier (12), a smoothing capacitor (14), an inverter (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 a three-phase power 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 inverter (16) inversely converts the capacitor voltage stored in the smoothing capacitor (14) into a three-phase AC voltage, and drives the motor (M) using the inverted three-phase AC voltage as a driving 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) of charging the smoothing capacitor (14) by diode rectification of the rectifier (12) until the capacitor voltage reaches a predetermined voltage value after the supply of the three-phase AC voltage is started; A charging step (S11) for controlling the switching of the switching element (12a) to charge the smoothing capacitor (14), an abnormality detecting step (S12) for detecting an abnormality of the sensor (32), and a step for driving the motor (M). And a control step (S13) of stopping the switching control and charging the smoothing capacitor (14) by diode rectification of the rectifier (12) when a driving-time sensor abnormality that 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 the sensor (32) is abnormal when the motor (M) is driven. As a result, the inverter (16) can continue to output the AC voltage, and the motor (M) allows the motor (M) to relatively move the table on which the workpiece is mounted and the tool for processing the workpiece. When a motor is used, the motor (M) can be driven to move at least one of the table and the tool to the retracted position. Therefore, when the sensor (32) detects an abnormality, it is possible to prevent the breakage of the tool and the processing failure from occurring.

  The abnormality detecting step (S12) is a step of, 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, An abnormality may be detected. Compared to the case where the abnormality of the sensor (32) is detected based on other than the deviation, it becomes easier to accurately detect the abnormality of the sensor (32).

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

  The motor drive device (10) is capable of switching between a supply state in which the three-phase AC voltage is supplied to the rectifier (12) and a cut-off 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 the drive-time sensor abnormality occurs. Thus, when an abnormality occurs in the sensor (32) at the time of driving the motor (M), the smoothing capacitor (14) can be reliably charged by diode rectification of the rectifier (12).

  In the control method, the switch (30) is maintained in the supply state until the protection operation for protecting the member moved by the driving of the motor (M) is completed after the drive-time sensor abnormality occurs, and the protection operation is completed. Thereafter, a disconnection step (S15) for switching the switch (30) to the disconnection state may be provided. This allows the operator to check the sensor (32) immediately after the protection operation is completed.

  The control method is to switch the switch (30) from the cut-off state to the supply state to start charging the smoothing capacitor (14). An initial control step (S6) of switching the switch (30) to the cutoff state to stop charging the smoothing capacitor (14) may be provided. This allows the operator to check the sensor (32) immediately after the abnormality has occurred.

  The control method includes the steps of: initially detecting an abnormality of the sensor (32) when at least one phase current value falls below the amplitude threshold after the at least two phase currents exceed a predetermined amplitude threshold. An abnormality detection step (S3) may be provided. Thereby, the abnormality of the sensor (32) can be detected even when the switching control of the rectifier (12) is not performed.

  In the control method, if no sensor abnormality occurs at the initial stage before the capacitor voltage accumulated in the smoothing capacitor (14) exceeds the voltage threshold, the switching control is started while maintaining the switch (30) in the supply state. (S5). Thereby, the switching control can be executed in a stable state.

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

Claims (16)

A motor drive device that drives a motor using a three-phase AC power supply,
A rectifier that has a plurality of switching elements and diodes connected in parallel to each of the switching elements, and converts a three-phase AC voltage supplied from the three-phase AC power supply to a DC voltage,
A smoothing capacitor connected to the DC side of the rectifier,
An inverter that inversely converts the capacitor voltage stored in the smoothing capacitor into the three-phase AC voltage and drives the motor with the inversely converted three-phase AC voltage as a driving voltage;
A sensor that detects a phase current value or a phase voltage value of at least two phases flowing through the rectifier,
An abnormality detection unit that detects abnormality of the sensor;
Controlling the switching element to charge the smoothing capacitor, and when a driving-time sensor abnormality that is an abnormality of the sensor at the time of driving the motor occurs, the switching control is stopped, and the rectifier is stopped. A control unit for charging the smoothing capacitor by diode rectification,
A motor drive device comprising: The motor drive device according to claim 1,
The abnormality detection unit detects an abnormality of the sensor when a deviation between a feedback value converted into a DQ coordinate system based on the phase current value or the phase voltage value and a current command value exceeds a predetermined deviation threshold. A motor drive to detect. The motor drive device according to claim 2, wherein
The motor drive device, wherein the abnormality detection unit detects an abnormality of the sensor when a state in which the deviation exceeds the deviation threshold continues for a predetermined period. The motor drive 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 supply of the three-phase AC voltage to the rectifier is cut off,
The motor drive device, wherein the control unit stops the switching control while maintaining the switch in the supply state when the drive-time sensor abnormality occurs. The motor drive device according to claim 4, wherein
The control unit maintains the switch in the supply state until the protection operation for protecting the member moved by driving the motor is completed after the drive-time sensor abnormality occurs, and the protection operation is completed. A motor drive device that switches the switch to the cutoff state thereafter. The motor drive device according to claim 4, wherein:
The controller is configured to switch the switch from the shut-off state to the supply state to start charging the smoothing capacitor, and to start the charging of the smoothing capacitor. A motor drive device that switches a heater to the cutoff state to stop charging the smoothing capacitor. The motor drive device according to claim 6, wherein
The abnormality detection unit, at the time of the initial charge, when the phase current value of at least one phase falls below the amplitude threshold after the phase current value of at least two phases exceeds a predetermined amplitude threshold, the sensor A motor drive that detects abnormalities in the motor. The motor drive device according to claim 6, wherein
The control unit is configured to perform the switching while maintaining the switch in the supply state when the initial sensor abnormality does not occur until the capacitor voltage stored in the smoothing capacitor exceeds a predetermined voltage threshold. A motor drive that starts control. A method of controlling a motor drive device that drives a motor using a three-phase AC power supply,
The motor drive device,
A rectifier that has a plurality of switching elements and diodes connected in parallel to each of the switching elements, and converts a three-phase AC voltage supplied from the three-phase AC power supply to a DC voltage,
A smoothing capacitor connected to the DC side of the rectifier,
An inverter that inversely converts the capacitor voltage stored in the smoothing capacitor into the three-phase AC voltage, and supplies the inversely converted three-phase AC voltage to the motor as a drive voltage;
A sensor that detects a phase current value or a phase voltage value of at least two phases flowing through the rectifier,
With
From the start of the supply of the three-phase AC voltage until the capacitor voltage reaches a predetermined voltage value, an initial charging step of charging the smoothing capacitor by diode rectification of the rectifier,
A charging step of controlling the switching element to charge the smoothing capacitor,
An abnormality detection step of detecting an abnormality of the sensor,
A control step of stopping the switching control when a drive-time sensor abnormality that is an abnormality of the sensor at the time of driving the motor and charging the smoothing capacitor by diode rectification of the rectifier;
The control method of the motor drive device which has a. It is a control method of the motor drive device of Claim 9, Comprising:
The abnormality detecting step includes detecting an abnormality of the sensor when a deviation between a feedback value converted into a DQ coordinate system based on the phase current value or the phase voltage value and a current command value exceeds a predetermined deviation threshold. A control method of the motor drive device to be detected. It is a control method of the motor drive device of Claim 10, Comprising:
The method for controlling a motor drive device, wherein the abnormality detecting step detects an abnormality of the sensor when a state in which the deviation exceeds the deviation threshold continues for a predetermined period. It is a control method of the motor drive device as described in any one of Claims 9-11, Comprising:
The motor driving 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 of a motor drive device, wherein when the drive-time sensor abnormality occurs, the switching control is stopped while the switch is maintained in the supply state. It is a control method of the motor drive device of Claim 12, Comprising:
The switch is maintained in the supply state until a protection operation for protecting a member moved by driving the motor is completed after the drive-time sensor abnormality occurs, and the switch is maintained after the protection operation is completed. A method for controlling a motor drive device, the method comprising: It is a control method of the motor drive device of Claim 12 or 13, Comprising:
When an 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 to start charging the smoothing capacitor, the switch is placed in the cutoff state. A control method for the motor drive device, comprising: an initial control step of stopping the charging of the smoothing capacitor by switching to the first mode. It is a control method of the motor drive device of Claim 14, Comprising:
When at least one phase current value of at least one phase falls below the amplitude threshold after the phase current values of at least two phases have exceeded a predetermined amplitude threshold, the apparatus has an initial abnormality detection step of detecting an abnormality of the sensor. , A method of controlling a motor drive device. It is a control method of the motor drive device of Claim 14, Comprising:
If the initial sensor abnormality does not occur until the capacitor voltage stored in the smoothing capacitor exceeds a predetermined voltage threshold, the start of the switching control while maintaining the switch in the supply state is started. A method for controlling a motor driving device, comprising:

Images