JP5988857B2 - Motor control device and phase loss detection method - Google Patents

Description

  The present invention relates to a motor control device and a phase loss detection method.

In controlling the motor, it is performed in advance to detect that an abnormality has occurred in the motor coil before driving the motor. For example, it is determined whether or not the motor is disconnected before driving the motor, and it is confirmed that the disconnection has not occurred. It becomes possible to prevent.
In detecting the abnormality of the motor, not only the determination of whether or not the motor can be energized but also the detection of the phase failure abnormality in the motor is performed (for example, Patent Document 1).

JP 2011-051695 A

  In the technique described in Patent Document 1, the phase loss of the motor is detected based on the voltage of the coil of each phase when a predetermined current is supplied to the motor. However, depending on the positional relationship between the stator and the rotor (or the mover) of the motor, there is a problem that an abnormality such as a phase failure of the motor cannot be detected.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor control device and a phase loss detection method that can improve the accuracy of detecting a motor abnormality.

  In order to solve the above problem, the present invention detects a deficient phase determination command output unit that outputs a d-axis current value and a q-axis current value used when detecting an abnormality in the coil, and detects an electrical angle of the motor. If the detected electrical angle is an angle where there is a coil of a phase where the current value to be energized is 0 when energization is performed with the q-axis current value being 0, the detected electrical angle is corrected to a predetermined value. When the electrical angle corrected by the angle is selected and the coil is not an angle where there is a coil of a phase where the current value to be energized is 0 when energization is performed with the q-axis current value being 0 in the detected electrical angle, The phase loss detection angle correction unit for selecting the detected electrical angle, the d-axis current value and the q-axis current value output from the phase loss determination command output unit, and the electrical angle selected by the phase loss detection angle correction unit. Energization to energize each coil of the motor based on And an open phase determination unit that determines whether or not an abnormality has occurred in any of the coils included in the motor, based on a current flowing through each coil when the energization unit energizes the motor. It is a motor control device characterized by having.

  Further, in order to solve the above problem, the present invention is a phase loss detection method performed by a motor control device that controls a motor having a plurality of coils, and detects an electrical angle of the motor and detects the detected electrical angle. When the q-axis current value is 0 and the current value to be energized is an angle where there is a coil of a phase where the current value to be energized is 0, the electrical angle obtained by correcting the detected electrical angle with a predetermined correction angle is If the selected electrical angle is not an angle where there is a phase coil in which the current value to be energized is 0 when energization is performed with the q-axis current value set to 0 at the detected electrical angle, the detected electrical angle is selected. Each coil of the motor based on the phase loss detection angle correction step, the d-axis current value and the q-axis current value used when detecting an abnormality in the coil, and the electrical angle selected in the phase loss detection angle correction step Through And an open phase determination step of determining whether or not an abnormality has occurred in any of the coils included in the motor based on the current flowing in each coil of the motor in the energization step. This is a phase loss detection method characterized by the above.

  According to the present invention, since driving of the motor is suppressed so that current flows through the coils of each phase, the motor abnormality can be detected regardless of the electrical angle of the motor, and the accuracy of detecting the motor abnormality is detected. Can be improved.

It is a schematic block diagram which shows the structure of the motor system 1 in embodiment which concerns on this invention. 4 is a schematic diagram showing an electrical angle in a motor 30. FIG. It is a flowchart which shows the phase loss detection process which the motor control apparatus 10 in the embodiment performs. It is a graph which shows an example of the d-axis current value and the q-axis current value when an open phase occurs. It is a graph which shows an example of the d-axis current value and the q-axis current value when the phase loss has occurred and the rotor is positioned at the non-detection angle.

  Hereinafter, a motor control device and a phase loss detection method according to an embodiment of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where a motor control apparatus controls a three-phase alternating current motor.

  FIG. 1 is a schematic block diagram showing a configuration of a motor system 1 in the present embodiment. As shown in FIG. 1, the motor system 1 includes a motor control device 10, a motor 30, and an encoder 31. The motor 30 has coils for U phase, V phase, and W phase. The motor 30 is driven by electric power supplied from the motor control device 10 to each coil.

  The motor control device 10 performs control to drive the motor 30 based on a position command value input from a host control device or the like and the electrical angle of the motor 30 detected by the encoder 31. Further, when a phase loss detection command is input from a host control device or the like, the motor control device 10 determines whether or not an abnormality has occurred in any of the coils of the motor 30. The motor control device 10 outputs a determination result. Specifically, the motor control device 10 performs energization that does not generate torque based on the electrical angle of the motor 30, and detects an abnormality in each coil based on the current value that flows in each phase coil of the motor 30. Thereby, the abnormality in each coil can be detected with almost no motor 30 being driven. The abnormality in the coil is an abnormality in energization such as disconnection of the coil itself, poor connection of the coil in the motor 30, and poor connection between the motor control device 10 and the motor 30. The phase loss means that the above abnormality occurs in any one of the coils of each phase of the motor 30.

  The motor control device 10 includes a position / speed control unit 11, a control command switch 12, a d-axis current controller 13, a q-axis current controller 14, an energization unit 15, a three-phase two-phase converter / vector rotation. A phase loss determination command output unit 21, a phase loss determination unit 22, and a phase loss detection angle correction unit 23. The energization unit 15 includes a two-phase / three-phase converter / vector rotator 16 and an inverter 17.

  The position speed control unit 11 calculates a q-axis current command value by PID control or the like based on the input position command value and the electrical angle input from the encoder 31. For example, when the position command value is given by the mechanical angle of the motor 30, the position / speed control unit 11 calculates the mechanical angle of the motor 30 from the input electrical angle. The position / speed controller 11 calculates a speed command value from the deviation between the calculated mechanical angle and the position command value. The position speed control unit 11 calculates the q-axis current command value from the deviation between the rotational speed of the motor 30 calculated from the change amount of the electrical angle and the position command value. The position / speed control unit 11 outputs the calculated q-axis current command value and a predetermined d-axis current command value to the control command switch 12. Note that the d-axis current command value output by the position / speed control unit 11 is 0 or a value close to 0.

  The phase loss determination command output unit 21 stores in advance a d-axis current command value and a q-axis current command value used when the phase loss of the motor 30 is detected, and the stored d-axis current command value and The q-axis current command value is output to the control command switch 12. The q-axis current command value stored in the phase loss determination command output unit 21 is 0 or a value close to 0, and the d-axis current command value is a predetermined value.

  The control command switching unit 12 outputs a d-axis current command value and a q-axis current command value output from the position / speed control unit 11 and a phase loss determination command output unit 21 according to the control of the phase loss determination unit 22. One of the d-axis current command value and the q-axis current command value is selected. The control command switch 12 outputs the selected d-axis current command value to the d-axis current controller 13 and outputs the selected q-axis current command value to the q-axis current controller 14.

  The d-axis current controller 13 is based on the deviation between the d-axis current command value output from the control command switch 12 and the d-axis current value input from the three-phase two-phase converter / vector rotator 18. A d-axis voltage command value for setting the deviation to 0 (zero) is calculated. The d-axis current controller 13 outputs the calculated d-axis voltage command value to the two-phase / three-phase converter / vector rotator 16.

  The q-axis current controller 14 is based on the deviation between the q-axis current command value output from the control command switch 12 and the q-axis current value input from the three-phase two-phase converter / vector rotator 18. A q-axis voltage command value for setting the deviation to 0 (zero) is calculated. The q-axis current controller 14 outputs the calculated q-axis voltage command value to the two-phase / three-phase converter / vector rotator 16.

  The two-phase / three-phase converter / vector rotator 16 includes a d-axis voltage command value output from the d-axis current controller 13, a q-axis voltage command value output from the q-axis current controller 14, and a phase loss detection angle correction. Based on the electrical angle input from the unit 23, voltage command values for the U phase, the V phase, and the W phase are calculated. The two-phase three-phase converter / vector rotator 16 outputs the calculated U-phase, V-phase, and W-phase voltage command values to the inverter 17.

  The inverter 17 is a U-phase, V-phase, or W-phase voltage that the motor 30 has the voltages indicated by the voltage command values of the U-phase, V-phase, and W-phase output from the two-phase / three-phase converter / vector rotator 16. Apply to coil. For example, the inverter 17 performs PWM control on the external voltage supplied from the outside based on the voltage command value of each phase, converts the external voltage into a voltage indicated by the voltage command value, and is obtained by conversion. The applied voltage is applied to each phase coil of the motor 30.

  As described above, the energization unit 15 including the two-phase three-phase converter / vector rotator 16 and the inverter 17 is configured to input the d-axis current command value and the q-axis current command value and the input electrical angle. Based on this, the coils of each phase of the motor 30 are energized.

  The three-phase / two-phase converter / vector rotator 18 is based on the current value flowing through each coil of the motor 30 detected by a current transformer (not shown) and the electrical angle output by the phase loss detection angle correction unit 23. A d-axis current value and a q-axis current value are calculated. The three-phase / two-phase converter / vector rotator 18 outputs the calculated d-axis current value to the d-axis current controller 13 and the missing phase determination unit 22. The three-phase / two-phase converter / vector rotator 18 outputs the calculated q-axis current value to the q-axis current controller 14 and the missing phase determination unit 22.

  The phase loss determination unit 22 controls the control command switch 12 and the phase loss detection angle correction unit 23 based on a phase loss detection command input from the outside. Specifically, the phase loss determination unit 22 outputs a d-axis current command value and a q-axis current command value input from the phase loss determination command output unit 21 when a phase loss detection command is input. 12 is selected. On the other hand, the phase loss determination unit 22 performs control to cause the control command switch 12 to select the d-axis current command value and the q-axis current command value input from the position / speed control unit 11 when the phase loss detection command is not input. .

  The phase loss determination unit 22 controls the phase loss detection angle correction unit 23 to perform an electrical angle correction process when a phase loss detection command is input. On the other hand, the phase loss detection unit 22 performs control to output the electrical angle input from the encoder 31 to the two-phase / three-phase converter / vector rotator 16 when the phase loss detection command is not input. To do.

  Further, the phase loss determination unit 22 determines that the motor 30 is based on the d-axis current value and the q-axis current value input from the three-phase / two-phase converter / vector rotator 18 when a phase loss detection command is input. It is determined whether or not an abnormality has occurred in any one of the coils of each phase. The phase loss determination unit 22 outputs the determination result to the outside.

  The phase loss detection angle correction unit 23 switches whether to perform correction processing on the electrical angle output by the encoder 31 according to the control of the phase loss determination unit 22. Specifically, when detecting an open phase, the open phase detection angle correction unit 23 performs a correction process according to the electrical angle output from the encoder 31 and then converts the electrical angle into a two-phase / three-phase converter / Output to the vector rotator 16 and the three-phase to two-phase converter / vector rotator 18. When the phase loss is not detected, that is, when the motor 30 is driven, the phase loss detection angle correction unit 23 converts the electrical angle output from the encoder 31 to the two-phase / three-phase converter / vector rotator 16 and the three-phase. Output to the two-phase converter / vector rotator 18.

  Here, the correction process performed by the phase loss detection angle correction unit 23 will be described. FIG. 2 is a schematic diagram showing an electrical angle in the motor 30. Here, the case where the motor 30 is a one-pole pair three-phase AC motor is shown. The electrical angle when the S pole of the rotor faces the U-phase coil (U) and the N pole of the rotor faces the U-phase coil (￣U) is 0 degree. In the configuration shown in the figure, the motor 30 has coils arranged in the order of coil (U), coil (￣V), coil (W), coil (￣U), and coil (V) in the clockwise direction. ing. In FIG. 2, letters with “￣ (overline)” on U, V, and W are described as ￣U, ￣V, and ￣W in this specification.

  In the motor 30 having the configuration shown in FIG. 2, when the rotor is positioned at the electrical angles of 30 degrees and 210 degrees, even if energization that does not generate rotational torque, that is, energization that sets the q-axis current value to 0, is performed. No current flows through the V-phase coil. Therefore, when the rotor is at a position of an electrical angle of 30 degrees or an electrical angle of 210 degrees, an abnormality in the V phase cannot be detected by energization that does not generate rotational torque. Therefore, the phase loss detection angle correction unit 23 performs a correction process for shifting the electrical angle by adding (or subtracting) a predetermined correction angle to the electrical angle when the rotor is at a position where the electrical angle is 30 degrees or 210 degrees. Do. By conducting energization based on the electrical angle obtained by the correction process, a current also flows through the V-phase coil, so that an abnormality in the V-phase can be detected. The correction angle may be about 3 degrees, for example. Even when the correction angle is 3 degrees, the angle at which the motor 30 actually rotates is (correction angle / pole pair number). For example, in the case of a four-pole motor, the mechanical angle rotated by energization is 0.75 degrees or less.

In addition, when the rotor is located at positions where the electrical angle is 90 degrees and 270 degrees, an abnormality in the U phase cannot be detected. The phase loss detection angle correction unit 23 similarly performs a correction process for smoothing the electrical angle when the rotor is at the position of the electrical angle of 90 degrees or 270 degrees. In addition, when the rotor is located at positions where the electrical angle is 150 degrees and 330 degrees, an abnormality in the W phase cannot be detected. The phase loss detection angle correction unit 23 similarly performs correction processing for shifting the electrical angle when the rotor is located at the position of the electrical angle of 150 degrees or 330 degrees.
In other words, the phase loss detection angle correction unit 23 corrects the electrical angle when it is an electrical angle in which there is a phase coil in which the current value to be energized is 0 when energization is performed without generating rotational torque. Process.

  FIG. 3 is a flowchart showing a phase loss detection process performed by the motor control device 10 according to the present embodiment. For example, if a phase loss detection command is input before the drive control for the motor 30 is performed, the phase loss detection process is started.

In the motor control device 10, when the phase loss detection process is started, the phase loss determination unit 22 controls the control command switching unit 12 to switch between the d-axis current command value and the q-axis current command value (step). S11).
The phase loss detection angle correction unit 23 acquires the electrical angle θ detected by the encoder 31 (step S12).

The phase loss detection angle correction unit 23 determines whether or not the acquired electrical angle θ is a non-detection angle at which any coil abnormality cannot be detected (step S13), and when the electrical angle θ is not a non-detection angle (step S13). Step S13: NO), processing proceeds to step S15.
On the other hand, when the electrical angle θ is a non-detection angle (step S13: YES), the phase loss detection angle correction unit 23 performs a correction process for shifting the electrical angle θ by a predetermined angle (step S14), and the process proceeds to step S15. .

  Here, the non-detection angles are electrical angles of 30 degrees, 90 degrees, 150 degrees, 210 degrees, 270 degrees, and 330 degrees in the motor 30 having the configuration shown in FIG. The non-detection angle is determined according to the number of phases and poles in the motor 30.

  The two-phase / three-phase converter / vector rotator 16 includes an electrical angle input from the phase loss detection angle correction unit 23 and a d-axis voltage command value input from the d-axis current controller 13 and the q-axis current controller 14. Based on the q-axis voltage command value, the U-phase, V-phase, and W-phase voltage command values are calculated. The inverter 17 energizes the motor 30 based on the U-phase, V-phase, and W-phase voltage command values (step S15).

The three-phase / two-phase converter / vector rotator 18 is energized from the current values flowing in the U-phase, V-phase, and W-phase coils by energization in step S15 and the electrical angle output from the phase loss detection angle correction unit 23. Current values (d-axis current value and q-axis current value) are acquired (step S16).
The phase loss determination unit 22 determines whether the d-axis current value and the q-axis current value acquired by the three-phase / two-phase converter / vector rotator 18 satisfy a predetermined criterion (step S17).

  As a reference for the d-axis current value and the q-axis current value, for example, the difference between the d-axis current value and the d-axis current command value output from the phase loss determination command output unit 21 is 10% of the d-axis current command value. Or whether the difference between the q-axis current value and the q-axis current command value output by the phase loss determination command output unit 21 is less than 10% of the q-axis current command value. That is, if the two differences are both less than 10%, it is determined that no abnormality has occurred in any of the coils. On the other hand, if any of the two differences is 10% or more, it is determined that an abnormality has occurred in any of the coils.

When the energization current values (d-axis current value and q-axis current value) satisfy the standard (step S17: YES), the phase loss determination unit 22 outputs a detection result indicating that no abnormality has been detected ( Step S18), the phase loss detection process is terminated.
On the other hand, when the energization current values (d-axis current value and q-axis current value) do not satisfy the standard (step S17: NO), the phase loss determination unit 22 outputs a detection result indicating that an abnormality has been detected. (Step S19), the phase loss detection process is terminated.

  The motor control device 10 performs abnormality detection energization to the motor 30 with a command value at which no rotational torque is generated in the motor 30, that is, a d-axis current command value as 0 and a q-axis current command value as a predetermined value. An abnormality occurs in the coil when there is a large difference between the d-axis current value and the q-axis current value calculated from the current values flowing in the coils of each phase and the d-axis current command value and the q-axis current command value. It is determined that At this time, if the rotor is positioned at an electrical angle at which the phase failure cannot be detected by the d-axis current command value and the q-axis current command value, all electrical angles are obtained by conducting energization with the electrical angle shifted. It is possible to detect a phase failure in. As described above, the phase loss can be detected regardless of the position of the rotor (that is, the electrical angle), and the accuracy of detecting the phase loss can be improved.

FIG. 4 is a graph illustrating an example of a d-axis current value and a q-axis current value when an open phase occurs. In the figure, the horizontal axis represents time and the vertical axis represents current. The graph shown by the solid line shows the change between the d-axis current value (I _d ) and the q-axis current value (I _q ) when an open phase occurs. A graph indicated by a broken line indicates a change between the d-axis current value (I _d ) and the q-axis current value (I _q ) when no phase loss occurs. As shown in the figure, when an open phase occurs, a difference occurs between the d-axis current value and the q-axis current value.

  FIG. 5 is a graph showing an example of the d-axis current value and the q-axis current value when an open phase occurs and the rotor is positioned at a non-detection angle. In the figure, the horizontal axis represents time and the vertical axis represents current. Similar to FIG. 4, the graph indicated by a solid line indicates when an open phase occurs, and the graph indicated by a broken line indicates when no open phase occurs. It can be seen that when the rotor is positioned at a non-detection angle, the q-axis current value can be changed by energizing with the electrical angle corrected, and an open phase can be detected.

  In the above-described embodiment, the case where the motor 30 is a three-phase AC motor has been described. However, the motor 30 may be a motor having a plurality of phase coils.

  Further, in the above-described embodiment, the configuration in which the motor control device 10 includes each functional unit has been described. However, the motor control device 10 may have a computer system inside. In this case, the phase loss detection process described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  DESCRIPTION OF SYMBOLS 10 ... Motor control apparatus, 15 ... Current supply part, 21 ... Missing phase determination command output part, 22 ... Missing phase judgment part, 23 ... Missing phase detection angle correction part, 30 ... Motor

Claims (3)

A motor control device for controlling a motor including a plurality of coils,
A phase loss determination command output unit for outputting a d-axis current value and a q-axis current value used when detecting an abnormality in the coil;
When the electric angle of the motor is detected, and the detected electric angle is an angle where there is a coil of a phase where the current value to be energized is 0 when energization is performed with the q-axis current value being 0, the detection is performed. An electrical angle obtained by correcting the electrical angle with a predetermined correction angle is selected, and a coil having a phase in which the current value to be energized becomes 0 when energization is performed with the q-axis current value set to 0 at the detected electrical angle. If it is not an existing angle, an open phase detection angle correction unit that selects the detected electrical angle;
An energization unit that energizes each coil of the motor based on the d-axis current value and the q-axis current value output by the phase loss determination command output unit, and the electrical angle selected by the phase loss detection angle correction unit;
An open phase determination unit that determines whether or not an abnormality has occurred in any of the coils included in the motor, based on a current flowing through each coil when the energization unit energizes the motor;
A motor control device comprising: The motor control device according to claim 1,
A converter for calculating a d-axis current value and a q-axis current value from the current values flowing in the coils of the motor;
The phase loss determination unit
When the difference between the d-axis current value calculated by the converter and the d-axis current value output by the phase loss determination command output unit is greater than or equal to a predetermined threshold, or q calculated by the converter When the difference between the shaft current value and the q-axis current value output by the phase loss determination command output unit is equal to or greater than the threshold value, it is determined that an abnormality has occurred in any of the coils included in the motor. A motor control device. A phase loss detection method performed by a motor control device that controls a motor including a plurality of coils,
When the electric angle of the motor is detected, and the detected electric angle is an angle where there is a coil of a phase where the current value to be energized is 0 when energization is performed with the q-axis current value being 0, the detection is performed. An electrical angle obtained by correcting the electrical angle with a predetermined correction angle is selected, and a coil having a phase in which the current value to be energized becomes 0 when energization is performed with the q-axis current value set to 0 at the detected electrical angle. If the angle does not exist, the phase loss detection angle correction step for selecting the detected electrical angle;
An energization step of energizing each coil of the motor based on a d-axis current value and a q-axis current value used when detecting an abnormality in the coil, and an electrical angle selected in the phase loss detection angle correction step;
An open phase determination step of determining whether or not an abnormality has occurred in any of the coils included in the motor, based on the current flowing in each coil of the motor in the energization step;
A phase loss detection method characterized by comprising:

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