JP2014155356A - Control device for ac motor and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an AC motor which is capable of executing abnormality processing by detecting abnormality in a voltage phase sequence, wiring of a rotation angle sensor and the number of magnetic poles.SOLUTION: A control device comprises: a phase sequence matching determination section 24 for determining, as a first determination, whether a commanded rotation direction given by an operation command of an AC power 10 is matched with a detected rotation direction obtained from an output signal of a resolver 11 and, when it is determined that the commanded rotation direction and the detected rotation direction are matched, determines, as a second determination whether the commanded rotation direction is matched with an actual rotation direction; an axis multiple detection section 25 for detecting an axis multiple from the output signal of the resolver 11 when it is determined that the commanded rotation direction and the actual rotation direction are matched; and a normality/abnormality detection section 26 for detecting normality/abnormality in a phase sequence of voltages to be applied to the motor 10 and determining, as a third determination, whether the axis multiple detected by the axis multiple detection section 25 and the number of magnetic poles in the motor 10 are matched.

Description

  The present invention relates to a control device that operates an AC motor at a variable speed using information fed back by a rotation angle detection sensor such as a resolver. Specifically, it is determined whether the rotation direction of the AC motor detected by the rotation angle sensor or the actual rotation direction matches the rotation direction by the operation command or the direction desired by the user, and the voltage applied to the AC motor is determined. The present invention relates to a control device and control method for an AC motor that can detect normality / abnormality of the phase sequence and the wiring of the output line of the rotation speed sensor.

Pulse encoders and resolvers are widely used as rotation angle sensors for AC motors. A pulse encoder generally outputs A-phase, B-phase, and Z-phase pulses. The A-phase pulse and the B-phase pulse have a phase difference of 90 degrees from each other, and the order of rising and falling of each phase pulse is different. Therefore, if the order is monitored, the rotation direction of the motor can be detected. If the A-phase pulse or B-phase pulse is counted, the rotation angle and rotation speed of the rotor can be obtained.
Further, only one Z-phase pulse is output per rotation of the motor. By using this Z-phase pulse as a reference (origin) of the rotation angle, the angle error can be removed for each rotation of the rotor, so that the Z-phase pulse is usually called a clear signal (pulse).
Further, when a resolver is used as the rotation angle sensor, a sine wave and a cosine wave, which are output signals of the resolver, are input to an R / D (resolver / digital) converter, and pulses of A phase, B phase, and Z phase are input. The rotation angle is detected and the angle error is removed in the same manner as described above using these pulses.

When vector control of an AC motor is performed using a rotation angle sensor, U, V, and W phase wiring (voltage phase order) of a power line that applies a three-phase AC voltage to the motor, or an output line (output line) of the rotation angle sensor If the wiring of () is incorrect, for example, the rotational speed detected by the rotational angle sensor becomes a negative number with respect to the actual rotational speed.
In addition, the relationship between the voltage phase sequence and the rotation direction of an AC motor varies depending on the manufacturer. When the power lines are connected in the U, V, W phase sequence, the motor may rotate counterclockwise (CCW). , It may rotate clockwise (CW). That is, even if the electric motor is connected in accordance with the phase order of the power lines U, V, and W, the rotation direction of the electric motor at that time does not necessarily match the rotation direction desired by the user.

In order to solve such a problem, for example, a method for controlling an AC motor shown in Patent Document 1 is provided.
FIG. 7 is a configuration diagram of the control device described in Patent Document 1. In FIG. 7, an output signal of a pulse encoder 201 as a rotation angle sensor attached to the induction motor 100 is input to a speed / motor rotation direction detection circuit 202, and a speed / motor rotation direction detection signal a is generated. In addition, the current and voltage of the electric motor 100 are detected by the current sensor 203 and the voltage sensor 204 and input to the speed / motor rotation direction estimation calculation circuit 205 to generate the speed / motor rotation direction estimation signal b.

  These signals a and b and a forward / reverse polarity speed command c input through the switch 206 during normal operation are input to a PE (pulse encoder) / motor rotation direction determination circuit 207. In this determination circuit 207, it is determined whether or not the rotation directions of the pulse encoder 201 and the electric motor 100 coincide with the rotation direction based on the speed command, and the determination result is stored in the storage device 208. When the rotational direction detected by the pulse encoder 201 is abnormal, the speed / motor rotational direction detection circuit 202 outputs the output of the pulse encoder 201 via the detected rotational direction change circuit 209 based on the information stored in the storage device 208. Correct the signal. When the rotation direction of the electric motor 100 is abnormal, a phase sequence change command is sent to the output voltage command phase sequence change circuit 210 based on the information stored in the storage device 208, and the PWM control circuit 211 and the inverter 212. The phase order of the three-phase AC voltage applied to the electric motor 100 via the is changed.

The deviation between the speed command c with polarity and the motor speed input via the switch 213 is input to the speed controller 214, and the output generated by the vector control arithmetic circuit 215 that operates to make this deviation zero. The voltage command is input to the output voltage command phase change circuit 210 via the switch 216.
Reference numeral 217 denotes a switch that is turned on when V / F constant control is performed using an open loop. During open loop control, a speed command c with polarity is input to the V / F control arithmetic circuit 218 via the switch 217 and output. A voltage command is generated, and this output voltage command is input to the output voltage command phase sequence change circuit 210 via the switch 216.
Further, the block 220 is for executing the determination of the rotation direction of the pulse encoder 201 and the electric motor 100 offline. A speed controller or a forward / reverse signal that has been previously patterned is sent to the speed controller via the switch 206. It is configured to output to the 214 side.

FIG. 8 is a flowchart showing the operation of this prior art.
As described above, an operation command (speed command) in a desired rotation direction is given to the electric motor 100, and the rotation direction is detected based on the feedback signal from the pulse encoder 201 (steps S1 and S2). Then, by comparing the detected rotation direction with the rotation direction based on the operation command, it is determined whether or not both rotation directions match (step S3). These processes are mainly executed by the speed / motor rotation direction detection circuit 202, the PE / motor rotation direction determination circuit 207, etc. of FIG.

  Next, when the determination result of step S3 is “YES”, the actual rotation direction of the motor 100 is detected together with the rotation speed from the current and voltage of the motor 100, and the detected actual rotation direction is the same direction as the operation command. Whether or not (steps S4 and S5). If the determination result in step S5 is “YES”, it is determined that the wiring of the power line of the electric motor 100 and the output line of the pulse encoder 201 is normal, and the process ends (step S6). These processes are mainly executed by the speed / motor rotation direction estimation calculation circuit 205, the PE / motor rotation direction determination circuit 207, etc. of FIG.

If the determination result in step S3 is “NO”, the actual rotation direction of the electric motor 100 is detected to determine whether or not the actual rotation direction is the same as the rotation direction based on the operation command (steps S7 and S8). In accordance with the result, abnormality determination of the pulse encoder 201 and output line replacement (steps S9 and S10), or abnormality determination and phase order change of the electric motor 100 are performed (steps S12 and S13). The result is stored in the storage device 208 (steps S11 and S14).
Furthermore, when the determination result of step S5 is “NO”, the abnormality determination of the electric motor 100 and the pulse encoder 201 is performed, the phase order is changed, and the output line of the pulse encoder 201 is replaced (steps S15 and S16). These determination / processing results are stored in the storage device 208 (step S17).

JP 2003-88154 A (paragraphs [0013] to [0016], [0018] to [0021], FIG. 1, FIG. 6, etc.)

In the prior art shown in FIGS. 7 and 8, it is determined whether or not the rotation direction detected by the pulse encoder 201 matches the rotation direction by the operation command, and the actual rotation detected from the current and voltage of the electric motor 100 is determined. By determining whether or not the direction coincides with the rotation direction by the operation command, the normality and abnormality of the voltage phase sequence of the electric motor 100 and the wiring of the output line of the pulse encoder 201 are detected. Further, according to this prior art, when detecting the actual rotation direction of the electric motor 100, it is also possible to detect a disconnection or a short circuit of the winding.
However, in this prior art, the rotation direction detected from the current and voltage of the electric motor 100 may not always coincide with the actual rotation direction.

On the other hand, when a resolver is used as the rotation angle sensor, it is necessary to match the number of magnetic poles of the electric motor 100 with the number of magnetic poles of the resolver rotor (hereinafter simply referred to as the number of magnetic poles of the resolver).
As described above, the output signal of the resolver is converted into A-phase, B-phase, and Z-phase pulses by the R / D converter. When the number of magnetic poles of the motor 100 is equal to the number of magnetic poles of the resolver, or when the number of magnetic poles of the motor 100 is an integral multiple of the number of magnetic poles of the resolver, the motor 100 has an electrical angle of 360 ° × N (N is an integer). Each time the motor rotates, one Z-phase pulse is output from the R / D converter as a clear signal. For this reason, it is possible to eliminate the accumulation of angle errors by determining the reference (origin) of the detection angle by the resolver using the Z-phase pulse, and to perform highly accurate motor control.

However, when the number of magnetic poles of the motor and the number of magnetic poles of the resolver do not match, or both are not in an integral multiple relationship, the R / D converter has a rotation angle of the electric motor 100 between an electrical angle of 0 ° to 360 °. Therefore, the Z-phase pulse is irregularly output, and as a result, the electric motor 100 cannot be controlled with high accuracy.
In this regard, in the conventional technique described in Patent Document 1, when a resolver is used as the rotation angle sensor, the number of magnetic poles of the electric motor 100 matches the number of magnetic poles of the resolver, that is, the number of magnetic poles of both is an integral multiple. It is not possible to determine whether or not the relationship is For this reason, there has been a problem that the Z-phase pulse is not generated at a desired timing, and errors in the detection angle by the resolver are accumulated, making it impossible to control the electric motor 100 with high accuracy.

  Therefore, the problem to be solved by the present invention is not only to accurately detect the actual rotation direction of the AC motor and determine whether or not it matches the rotation direction desired by the user, but also to determine the number of magnetic poles of the rotation angle sensor and the AC motor. A control device and a control method for an AC motor that can determine the matching with the number of magnetic poles of the AC motor, detect voltage phase order, rotation angle sensor wiring, abnormality in the number of magnetic poles, etc., and execute predetermined abnormality processing. It is to provide.

In order to solve the above-mentioned problems, a control device according to the present invention feeds a detection signal from a rotation angle sensor such as a resolver attached to an AC motor, and drives the motor at a variable speed, as described in claims 1 and 3. It is intended for an AC motor control device.
Then, the control device executes, as a first determination, whether or not the command rotation direction based on the operation command of the AC motor matches the detected rotation direction obtained from the output signal of the rotation angle sensor. A phase-sequence matching determination unit that executes, as a second determination, whether or not the command rotation direction and the actual rotation direction of the motor match when it is determined that the command rotation direction and the detected rotation direction match according to one determination; Prepare.
And a shaft multiple detector for detecting the shaft multiple of the rotation angle sensor from the output signal of the rotation angle sensor when it is determined by the second determination that the command rotation direction and the actual rotation direction coincide with each other. The normality / abnormality of the voltage phase sequence applied to the AC motor or the output line wiring of the rotation angle sensor is detected according to the determination result of the matching determination unit, and the shaft multiple detected by the shaft multiple detection unit and the AC motor A normality / abnormality detection unit that executes a determination as to whether or not the number of magnetic poles matches as a third determination.

According to a second aspect of the present invention, the normality / abnormality detecting unit detects a voltage phase sequence applied to the AC motor or an abnormality in the wiring of the output line of the rotation angle sensor. Alternatively, an operation of changing the wiring of the output line of the rotation angle sensor is performed, and an alarm is output when it is determined by the third determination that the shaft multiple of the rotation angle sensor and the number of magnetic poles of the AC motor do not match.
Here, as described in claim 4 or 9, it is desirable to detect the actual rotation direction of the electric motor based on a captured image or visual observation.

Furthermore, the control method according to the present invention is directed to a control method for an AC motor that feeds back an output signal of a rotation angle sensor such as a resolver attached to the AC motor and operates the motor at a variable speed. It is said.
This control method includes a first determination step for determining whether or not a command rotation direction given by an operation command for an AC motor matches a detected rotation direction obtained from an output signal of a rotation angle sensor; A second determination step for determining whether or not the command rotation direction and the actual rotation direction of the electric motor match when it is determined in the step that the command rotation direction and the detected rotation direction match; In addition, when the second determination step determines that the command rotation direction and the actual rotation direction coincide with each other, there is an axis multiple detection step for detecting the axis multiple of the rotation angle sensor from the output signal of the rotation angle sensor. Furthermore, it has the 3rd judgment step which judges whether the shaft multiple detected by the shaft multiple detection step and the magnetic pole number of an AC motor match.
Then, when the first judgment step or the second judgment step determines that they do not match, and when the third judgment step judges that there is no matching, an abnormality process is performed.

  According to the sixth aspect of the present invention, the abnormality process is performed in the order of the voltage phase applied to the AC motor when the first determination step or the second determination step determines that the two directions to be determined are not consistent. Alternatively, it is determined that the output line wiring of the rotation angle sensor is abnormal and the voltage phase sequence is changed or the output line wiring is changed, and the third determination step determines the shaft multiple of the rotation angle sensor and the number of magnetic poles of the AC motor. And outputting an alarm when it is determined that they do not match.

  Here, as described in claim 7, it is desirable to detect the shaft multiple of the rotation angle sensor by counting the number of Z-phase pulses generated from the output signal of the rotation angle sensor.

  When shifting to the third determination step, it is determined that the respective rotation directions coincide with each other in the first determination step and the second determination step, and the shaft multiple of the rotation angle sensor and the alternating current are further determined in the third determination step. When it is determined that the number of magnetic poles of the motor matches, the voltage phase order of the AC motor, the wiring of the output line of the rotation angle sensor, the shaft multiple, etc. are all normal. Therefore, as described in claim 8, there is no particular problem even if the AC motor is operated at a variable speed based on the output signal of the rotation angle sensor.

According to the present invention, the detected rotation direction of the AC motor by the rotation angle sensor is compared with the command rotation direction, and the actual rotation direction is compared with the command rotation direction. In this case, the AC motor can be normally operated at a variable speed by automatically changing the voltage phase sequence of the AC motor and the wiring of the output line of the rotation angle sensor.
In addition, it is possible to prompt the inspection, replacement, etc. of the rotation angle sensor by generating an alarm output when an abnormality occurs when the shaft multiple (number of magnetic poles) of the rotation angle sensor does not match the number of magnetic poles of the AC motor.

It is a block diagram which shows the drive system of the alternating current motor with which embodiment of this invention is applied. It is a flowchart which shows operation | movement of embodiment of this invention. It is explanatory drawing of the connection state in case a command rotation direction is normal rotation, and the state of a counter value. It is explanatory drawing of the connection state in case a command rotation direction is reverse rotation, and the state of a counter value. It is a figure for demonstrating the detection principle of the axial multiple of a resolver. It is a flowchart which shows the detection process of the axial multiple of a resolver. It is a block diagram of the prior art described in patent document 1. FIG. 10 is a flowchart showing the operation of the prior art described in Patent Document 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the case where a resolver is used as a rotation angle sensor will be described. However, the present invention is a bridge circuit including four magnetoresistive elements as described in paragraph [0023] of Japanese Patent No. 4691459, for example. The present invention is also applicable to a case where a rotation angle sensor is used in which a change in magnetic field intensity due to rotation of the rotor magnet is detected by the bridge circuit.

FIG. 1 is a block diagram showing an AC motor drive system to which a control device according to this embodiment is applied.
In FIG. 1, the control device 20 includes a speed control calculation unit 21, a PWM inverter 22, an R / D converter 23, a phase order matching determination unit 24, an axial multiple detection unit 25, a normal / abnormality detection unit 26, and a storage device 27. I have. A resolver 11 as a rotation angle detection sensor is directly connected to the rotating shaft of the AC motor 10 connected to the three-phase output terminals U, V, and W of the PWM inverter 22, and the output line 12 of the resolver 11 is connected to the R / D converter 23. Input terminals S1, S2, S3, and S4. The output line 12 outputs an angle detection signal having a sin waveform and a cos waveform whose phases are shifted by 90 ° in electrical angle.

The R / D converter 23 generates an A phase pulse, a B phase pulse, and a Z phase pulse based on the output signal of the resolver 11. These phase pulses are input to the speed control calculation unit 21, the phase order matching determination unit 24, and the axis multiple detection unit 25. The speed control calculation unit 21 receives an operation command (speed command with polarity), the respective phase pulses, and the terminal voltage and current of the AC motor 10 detected by the detector 28, and a three-phase voltage command for the PWM inverter 22. V _u , V _v , and V _w are output. The voltage commands V _u , V _v , and V _w are also input to the phase sequence matching determination unit 24, and the output signal of the phase sequence matching determination unit 24 along with the output signal of the shaft multiple detection unit 25 is normal / abnormal detection unit 26. Has been entered. Note that a signal indicating the actual rotation direction of the AC motor 10 is also input to the phase sequence matching determination unit 24 from the outside.
Further, a storage device 27 is connected to the speed control calculation unit 21 and the normal / abnormality detection unit 26.

Here, the phase sequence matching determination unit 24 detects the rotation direction (hereinafter also referred to as the command rotation direction) based on the operation command detected from the voltage commands V _u , V _v , and V _w , and the resolver 11 and the R / D converter 23. The detected rotation direction (hereinafter also referred to as a detected rotation direction) is detected.
Further, the axial multiple detector 25 detects the axial multiple based on each phase pulse output from the R / D converter 23. The axial multiple is a parameter indicating how many periods of the sin waveform and the cosine waveform output during one rotation of the rotor of the resolver 11, for example, a sin waveform output during one rotation of the rotor. If the cos waveform is 5 cycles, the axial multiple is 5, and this axial multiple matches the number of 11 magnetic poles of the resolver.

  The normality / abnormality detection unit 26 detects normality / abnormality of the voltage phase sequence applied to the AC motor 10 based on the output of the phase sequence matching determination unit 24, normality / abnormality of the wiring of the output line of the resolver 11, and The normality / abnormality of the resolver 11 is detected by making a matching judgment between the number of magnetic poles of the AC motor 10 and the axial multiple of the resolver 11. If an abnormality is detected as a result of these determinations, the change of the voltage phase sequence of the AC motor 10 or the change of the wiring of the output line of the resolver 11 is automatically performed, and an alarm is output as necessary. It is configured as follows.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.
First, an operation command (polarity speed command) is input to the speed control calculation unit 21 (step S101). This operation command includes information indicating the rotation direction (forward rotation, reverse rotation) of the AC motor 10. The speed control calculation unit 21 generates the voltage commands V _u , V _v , and V _w by, for example, sensorless control, V / f control, and the like without using the detection information from the resolver 11 to control the PWM inverter 22, and the AC motor 10 is driven.

Next, the phase sequence matching determination unit 24 detects the rotation direction of the AC motor 10 from the A phase pulse and the B phase pulse output from the R / D converter 23 based on the output signal of the resolver 11 (step S102). Then, it is determined whether or not the detected rotation direction matches the command rotation direction based on the operation command (step S103). If they match, the input of the actual rotation direction from the outside is waited (steps S103 YES, S104). ). When the detected rotation direction does not coincide with the command rotation direction, the normal / abnormality detection unit 26 detects an abnormality and changes the phase sequence of the applied voltage of the AC motor 10 (change of wiring of the power line) or the resolver 11. The output line is automatically changed (NO in steps S103 and S109), and the processes in and after step S101 are executed again. The detection result by the normal / abnormality detection unit 26, the voltage phase sequence before and after the change, the wiring state of the output line of the resolver 11, and the like are appropriately stored in the storage device 27.
Here, the operation of changing the voltage phase order and changing the wiring of the output line of the resolver 11 using the output of the normal / abnormality detection unit 26 can be easily realized by a known wiring changing operation.

Even when the rotational direction detected by the resolver 11 is the same as the command rotational direction (YES in step S103), as described above, the actual rotational direction is determined by the manufacturer of the AC motor 10, that is, the rotational direction desired by the user, that is, May differ from the command rotation direction. In this case, the control device 20 itself cannot determine whether or not the actual rotation direction matches the command rotation direction.
Therefore, in this embodiment, an image captured by the camera or a signal indicating the actual rotation direction visually detected is input from the outside to the phase sequence matching determination unit 24, and the actual rotation direction is compared with the command rotation direction. Thus, it is possible to determine the coincidence / non-coincidence in the rotational direction more accurately than in the prior art such as Patent Document 1.

  In other words, the phase sequence matching determination unit 24 determines whether or not the actual rotation direction input from the outside based on the photographed image or visual observation by the camera matches the command rotation direction (steps S104 and S105). Are equal to each other, the normality / abnormality detection unit 26 determines that the voltage phase order of the AC motor 10 and the wiring of the resolver 11 are normal, and the axial multiple detection unit 25 determines the axial multiple (number of magnetic poles) of the resolver 11. Is detected (YES in step S105, S106). If the actual rotation direction is different from the command rotation direction, the normal / abnormality detection unit 26 determines that an abnormality has occurred and automatically changes the phase sequence of the AC motor 10 and the output line of the resolver 11. (Step S105 NO, S110), and further, the processing after Step S101 is executed again.

Next, the normality / abnormality detection unit 26 determines whether or not the axial multiple of the resolver 11 matches the number of magnetic poles of the AC motor 10 (step S107). If they match, the resolver 11 is normal. It is determined that there is, and the fact and the axial multiple are stored in the storage device 27 and the process is terminated (YES in steps S107 and S108). The voltage phase order and the axial multiple of the resolver 11 stored in the storage device 27 are used as information when the AC motor 10 is operated next time.
If the axial multiple of the resolver 11 does not match the number of magnetic poles of the AC motor 10, the normal / abnormality detection unit 26 determines that the resolver 11 is abnormal, outputs an alarm, and ends (NO in step S107). S111)

  Each of the above processes will be specifically described with reference to FIG. Here, the rotation direction (command rotation direction) desired by the user is normal rotation, and the phase sequence matching determination unit 24 of the control device 20 causes the AC motor 10 to perform normal rotation based on the A-phase pulse and the B-phase pulse. It is assumed that the internal counter is counted up when it is determined that the

  FIG. 3A shows a case where the wiring of the power line of the AC motor 10 and the wiring of the output line of the resolver 11 are normal, and the command rotation direction matches the rotation direction detected by the resolver 11. In this case, the determination result in step S103 of FIG. 2 is “YES”, and the AC motor 10 can be operated at a variable speed without any problem.

However, even when it is determined that the AC motor 10 is rotating forward according to the state of the counter value, as shown in FIG. 3D, the wiring of the AC motor 10 and the resolver 11 are both incorrect, and the AC motor 10 Since the actual rotation direction does not coincide with the command rotation direction and may be reversed, step S104 waits for the input of the actual rotation direction from the outside.
In FIG. 3A, since the wiring of the AC motor 10 and the resolver 11 is normal, the actual rotation direction matches the command rotation direction, and the determination result in step S105 is “YES”. The detection of the axial multiple in step S106 and the matching determination in step S107 are sequentially executed.

  FIG. 3B shows a case where the power line of the AC motor 10 is miswired and the voltage phase order is wrong, but the output line of the resolver 11 is correctly wired. In this case, since the counter value is counted down, it is detected that the AC motor 10 is reversely rotated, and the detected rotation direction is different from the normal rotation that is the command rotation direction. Therefore, the determination result in step S103 is “NO”, and the process proceeds to step S109. In step S109, by changing the voltage phase order of the AC motor 10 or the wiring of the output line of the resolver 11, either state shown in FIG. 3A or FIG. 3D is obtained.

  FIG. 3C shows a state where the wiring of the power line of the AC motor 10, that is, the voltage phase sequence is normal, but the output line of the resolver 11 is miswired. In this case, the AC motor 10 normally rotates at first, but the rotation direction detected by the resolver 11 is reverse and the counter value counts down, which is different from the command rotation direction. Therefore, the determination result in step S103 is “NO”. The process proceeds to S109. That is, the same processing as in the case of FIG.

  FIG. 3D shows a state where both the power line wiring of the AC motor 10 and the output line of the resolver 11 are miswired. In this case, since the rotation direction detected by the resolver 11 coincides with the command rotation direction, the determination result in step S103 is “YES”, and there is no problem with the variable speed operation of the AC motor 10. However, as described above, the AC motor There is a possibility that the actual rotation direction of 10 is different from the command rotation direction. Therefore, the actual rotation direction input from the outside in step S105 is compared with the command rotation direction, and the processing in step S106 and subsequent steps or step S110 is executed according to the result.

FIG. 4 shows a connection state and a counter value state when the command rotation direction is reverse. In this case, the phase sequence matching determination unit 24 of the control device 20 detects that the rotation direction is reverse since the counter value counts down.
In each case of FIGS. 4A to 4D, the difference from FIGS. 3A to 3D is that the change of the counter value (count up / count down) is reversed, and the resolver 11 The processing contents corresponding to the coincidence / mismatch between the detected rotation direction and the command rotation direction and the coincidence / mismatch between the actual rotation direction and the command rotation direction are the same as in FIG.

  Next, FIG. 5 is a diagram for explaining the principle of detecting the axial multiple of the resolver 11 when the rotational speed of the AC motor 10 is constant. Here, the case where the number of pole pairs of the AC motor 10 is 3 (the number of magnetic poles is 6) will be described. In the AC motor 10 having the number of pole pairs of 3, the cycle in which the motor makes one rotation (360 ° in mechanical angle) corresponds to three cycles in electrical angle. Therefore, as shown in FIG. 5, when the axial multiple of the resolver 11 is 1, 3 and 6, the cycle of the Z-phase pulse (clear signal) and the cycle of the electrical angle of the AC motor 10 are an integer ratio.

When the shaft multiple is 1, one Z-phase pulse is generated for three electrical angle cycles of the motor, and when the shaft multiple is 3, one Z-phase pulse is generated for one cycle of the electrical angle of the motor. In the case where the axial multiple is 6, one Z-phase pulse is generated for each electrical angle cycle and half cycle of the motor. Therefore, for example, if the reference (origin) is determined by using one Z-phase pulse generated in one cycle of the electrical angle of the motor when the shaft multiple is 3 or 6, the detection angle error caused by the resolver 11 is eliminated. The angle detection accuracy can be increased.
However, when the shaft multiple in FIG. 5 is 2, the electrical angle of 3 periods of the motor corresponds to 2 periods of the Z-phase pulse, and the electrical angle period and the Z-phase pulse period have an integer ratio. Regardless, the Z-phase pulse occurs at a point in time within one cycle of the electrical angle of the motor. For this reason, the error in the detected angle by the resolver 11 cannot be easily corrected during operation, and the AC motor 10 may not be controlled.
Therefore, it is desirable that the number of magnetic poles of the AC motor 10 and the axial multiple of the resolver 11 have a predetermined integer ratio as in the axial multiples 1, 3, and 6 in FIG.

FIG. 6 is a flowchart showing the axial multiple detection processing of the resolver 11.
The AC motor 10 is rotated at a constant speed (step S201), and the number of Z-phase pulses generated for one rotation of the mechanical angle is recorded (step S202). Since the number of Z-phase pulses corresponds to the axial multiple of the resolver 11 as shown in FIG. 5, the axial multiple can be immediately detected from the number of Z-phase pulses (step S203).
Using the shaft multiple of the resolver 11 detected in this way, the matching judgment with the number of magnetic poles of the AC motor 10 is performed in step S107 of FIG. 2, and the processing of step S108 or step S111 described above is executed according to the result. finish.

As described above, according to the present invention, the rotation direction detected by the resolver 11 is compared with the command rotation direction, the actual rotation direction is compared with the command rotation direction, and the result of these comparisons is determined to be abnormal. In this case, the AC motor 10 can be normally operated at a variable speed by automatically changing the voltage phase sequence of the AC motor 10 or changing the wiring of the output line of the resolver 11.
In addition, it is possible to prompt the inspection, replacement, etc. of the resolver 11 by generating an alarm output at the time of abnormality when the axial multiple of the resolver 11 does not match the number of magnetic poles of the AC motor 10.

DESCRIPTION OF SYMBOLS 10: AC motor 11: Resolver 12: Output line 20: Control apparatus 21: Speed control calculating part 22: PWM inverter 23: R / D converter 24: Phase sequence matching judgment part 25: Shaft multiple detection part 26: Normal / abnormal Detection unit 27: storage device 28: detector

Claims (9)

In the control device for the AC motor that feeds back the output signal of the rotation angle sensor attached to the AC motor and operates the motor at a variable speed,
Judgment as to whether or not the command rotation direction given by the operation command of the electric motor and the detected rotation direction obtained from the output signal of the rotation angle sensor coincide with each other is executed as a first determination. A phase sequence matching determination unit configured to execute, as a second determination, whether or not the command rotation direction and the actual rotation direction of the motor match when it is determined that the command rotation direction and the detected rotation direction match. ,
A shaft multiple detection unit that detects a shaft multiple of the rotation angle sensor from an output signal of the rotation angle sensor when it is determined by the second determination that the command rotation direction and the actual rotation direction match;
According to the determination result of the phase sequence matching determination unit, the voltage phase sequence applied to the AC motor or the normality / abnormality of the wiring of the output line of the rotation angle sensor is detected and detected by the shaft multiple detection unit A normal / abnormality detection unit that executes a determination as to whether or not the shaft multiple and the number of magnetic poles of the AC motor match as a third determination;
An AC motor control device comprising: In the control apparatus for an AC motor according to claim 1,
The normal / abnormality detection unit
When an abnormality is detected in the voltage phase sequence applied to the AC motor or the wiring of the output line of the rotation angle sensor, the voltage phase sequence is changed or the output line of the rotation angle sensor is changed. An AC motor control device that outputs an alarm when it is determined by the third determination that the shaft multiple and the number of magnetic poles of the AC motor do not match. In the control apparatus for an AC motor according to claim 1 or 2,
The control apparatus for an AC motor, wherein the rotation angle sensor is a resolver. In the control apparatus of the alternating current motor according to any one of claims 1 to 3,
An AC motor control device that detects an actual rotation direction of the motor based on a photographed image or visual observation. In the control method of the AC motor that feeds back the output signal of the rotation angle sensor attached to the AC motor and operates the motor at a variable speed,
A first determination step of determining whether or not a command rotation direction given by an operation command of the electric motor and a detected rotation direction obtained from an output signal of the rotation angle sensor match;
A second determination step for determining whether or not the command rotation direction and the actual rotation direction of the motor match when it is determined by the first determination step that the command rotation direction and the detected rotation direction match; ,
A shaft multiple detection step of detecting a shaft multiple of the rotation angle sensor from an output signal of the rotation angle sensor when it is determined in the second determination step that the command rotation direction and the actual rotation direction match;
A third determination step of determining whether or not the shaft multiple detected by the shaft multiple detection step matches the number of magnetic poles of the AC motor;
Have
A control method for an AC motor, wherein abnormality processing is performed when it is determined that they do not coincide with each other in the first determination step or the second determination step, and when it is determined that there is no matching in the third determination step. . In the control method of the AC motor according to claim 5,
The abnormality processing is
When it is determined in the first determination step or the second determination step that the two directions to be determined are inconsistent, the voltage phase sequence applied to the AC motor or the wiring of the output line of the rotation angle sensor is abnormal. The step of determining and changing the voltage phase sequence or changing the wiring of the output line and the third determining step output an alarm output when it is determined that the shaft multiple and the number of magnetic poles of the AC motor do not match. Steps to do,
An AC motor control method comprising: In the control method of the AC motor according to claim 5 or 6,
A method for controlling an AC motor, comprising: detecting a shaft multiple of the rotation angle sensor based on a Z-phase pulse generated from an output signal of the rotation angle sensor. In the control method of the alternating current motor according to any one of claims 5 to 7,
An AC motor control method comprising: operating the motor at a variable speed based on an output signal of the rotation angle sensor when it is determined that matching is performed in the third determination step. In the control method of the alternating current motor according to any one of claims 5 to 8,
A method for controlling an AC motor, comprising: detecting an actual rotation direction of the motor based on a photographed image or visual observation.

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