JP6584371B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device with an axis deviation detection function.

  Conventionally, a sensorless control method based on an induced voltage using an adaptive observer is known as a method of controlling an AC rotating machine such as a synchronous machine or an induction machine. In the sensorless control method based on the induced voltage, the position sensor and the speed sensor can be omitted. However, since the induced voltage is small in the low-speed rotation region, it is difficult to detect or estimate the induced voltage, and the driving characteristics are deteriorated. For this reason, in the low speed range, a method has been developed in which voltage and current having a frequency different from the fundamental frequency of the AC rotating machine are superimposed and controlled based on the position detection result using the saliency of the inductance. In such a motor control device, an abrupt change in the load on the motor may cause a shaft misalignment. When the shaft misalignment occurs, the rotation of the motor decreases, and eventually the motor may stop and become uncontrollable. Therefore, a technique for accurately detecting the shaft misalignment has been demanded.

  Patent Document 1 as an example of the prior art discloses a technique that includes two different speed estimators and compares the estimated speeds to detect an axis deviation. In Patent Document 1, it is determined that the step out, the speed is reduced, and the stop mode is step out.

JP 2007-282389 A

  However, according to the above-described conventional technique, it is possible to detect a step-out, a speed reduction, and a stop mode, but the estimated phase is instantaneously generated due to a sudden load fluctuation. It is not possible to detect an axial deviation that continues to drive with a deviation of 180 degrees or 360 degrees. For this reason, there are problems such as not reaching the target position when the position is controlled.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a motor control device capable of detecting an axial deviation that continues to be driven with an estimated phase shifted by 180 degrees or 360 degrees with respect to an actual phase. .

In order to solve the above-described problems and achieve the object, a motor control device of the present invention estimates a motor magnetic flux that is a magnetic flux of a synchronous motor and outputs an armature reaction estimated magnetic flux, and the motor and a shaft displacement detecting unit for detecting the axial displacement based on the AC component of the motor magnetic flux obtained from the armature reaction estimated magnetic flux input from the magnetic flux estimator, the shaft displacement detection unit, the magnetic flux contained in the motor flux The armature reaction command magnetic flux, which is the magnetic flux generated by the current command flowing through the synchronous motor, is calculated using the current command, and the armature reaction estimated magnetic flux and the calculated armature reaction command magnetic flux are used. characterized by Rukoto comprising a detection section for obtaining an AC component of the motor flux.

  According to the present invention, there is an effect that it is possible to obtain a motor control device capable of detecting an axial deviation that keeps driving with an estimated phase shifted by 180 degrees or 360 degrees with respect to an actual phase.

1 is a block diagram showing a configuration example of a motor control device according to a first embodiment. The block diagram which shows the example of 1 structure of the axial deviation detection part shown in FIG. FIG. 6 is a block diagram showing an example of the configuration of an axis deviation detection unit in the second embodiment. The figure which shows an example of the inductance map in Embodiment 2 FIG. 9 is a block diagram showing a configuration example of an axis deviation detection unit in the third embodiment. FIG. 9 is a block diagram showing a configuration example of an axis deviation detection unit in the fourth embodiment.

  Hereinafter, a motor control device according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating a configuration example of the motor control device 2 according to the first embodiment of the present invention. In the motor control device 2 shown in FIG. 1, the overall drive control is sensorless vector control, but the phase estimation error correction is performed by the high frequency superimposition method in the low speed range, and the high frequency superposition method is performed in the medium speed range to the high speed range. This is performed only by sensorless vector control without performing phase estimation error correction. Here, in sensorless vector control, the rotational speed of the motor is estimated from the induced voltage of the motor without using the position sensor attached to the motor or without using the position sensor attached to the motor. In this method, the motor speed is controlled so as to match the speed command.

  Examples of the motor 1 include an embedded magnet type synchronous motor in which a permanent magnet is embedded in a rotor. In the motor 1, the axis in the direction of the magnetic flux produced by the magnetic poles of the rotor, that is, the central axis of the permanent magnet is defined as the d axis, and the axis that is electrically or magnetically orthogonal to the d axis, that is, the axis between the permanent magnets And The d axis is also called a magnetic flux axis, and the q axis is also called a torque axis.

  Although not shown, the linkage flux due to the d-axis current id is limited because a magnet with low permeability is in the middle, whereas the linkage flux due to the q-axis current iq is more than the magnet. Since it passes through a material with high magnetic permeability, it becomes large. An example of a material having a higher magnetic permeability than a magnet is silicon steel. During the steady operation of the motor 1, the d-axis magnetic resistance is larger than the q-axis magnetic resistance, and the d-axis inductance component Ld is smaller than the q-axis inductance component Lq. That is, the salient pole ratio Lq / Ld, which is the ratio of the q-axis inductance component Lq to the d-axis inductance component Ld, is greater than 1, and the motor 1 has saliency.

  A motor control device 2 shown in FIG. 1 is connected to the motor 1 and includes a voltage application unit 3, a current detection unit 4, an estimation unit 5, an axis deviation detection unit 6, and a control unit 7.

  The motor controller 2 normally estimates the magnetic pole position of the rotor using the saliency of the motor 1 during steady operation, and controls the driving speed of the motor 1 using the estimated magnetic pole position. In addition, when the magnetic pole position is shifted 180 degrees or 360 degrees instantaneously from the actual position due to sudden load fluctuations, the axis deviation detection unit 6 detects the axis deviation and stops driving the motor 1. To do.

  The voltage application unit 3 is a semiconductor power converter typified by a pulse width modulation (PWM) inverter. The voltage application unit 3 converts the DC voltage into a PWM-modulated three-phase AC voltage and applies it to the motor 1 based on the three-phase drive voltage commands Vu *, Vv *, and Vw * output from the control unit 7. To do.

  The current detection unit 4 is mounted on a power line between the motor 1 and the voltage application unit 3 and detects a three-phase motor current iu, iv, iw flowing between the motor 1 and the voltage application unit 3 from the power line. To the control unit 7. The current detector 4 can be exemplified by a current transformer. Note that the current may be detected by detecting only the current of two phases out of the three phases and calculating the remaining one-phase current using the fact that the motor current is in three-phase equilibrium.

  The control unit 7 performs sensor-less vector control as a whole, but performs phase estimation error correction by the high frequency superimposition method in the low speed range, and performs phase estimation error correction by the high frequency superposition method in the medium speed range to the high speed range. Maximum efficiency control or maximum torque control is performed by performing only sensorless vector control without performing it. The control unit 7 includes a high-frequency voltage generator 30, a voltage addition unit 31, a coordinate converter 32, a filter 33, a drive voltage command calculation unit 34, a d-axis current command calculation unit 35, and a q-axis current command calculation. Part 36. The drive voltage command calculation unit 34 includes a current controller 34a and a coordinate converter 34b. The command ω * is input to the q-axis current command calculation unit 36.

  The high-frequency voltage generator 30 controls the start and stop of the d-axis control current vector command id * calculated and output by the d-axis current command calculation unit 35 and the estimated speed ωr0 output by the speed and phase estimation unit 5a. A drive control signal that is a second high-frequency voltage command that is output from the coordinate converter 34b in the drive voltage command calculation unit 34 in accordance with the high-frequency voltage commands Vdh and Vqh that are first high-frequency voltage commands that are externally input. The high-frequency voltage commands Vuh, Vvh, and Vwh are different from the voltage commands Vu *, Vv *, and Vw *. The high-frequency voltage commands Vuh, Vvh, and Vwh may be different in frequency from the drive control voltage commands Vu *, Vv *, and Vw *, and are three-phase high-frequency voltage commands here.

  The voltage adding unit 31 outputs the three-phase high-frequency voltage commands Vuh, Vvh, and Vwh output from the high-frequency voltage generator 30 to the drive control voltage command Vu output from the coordinate converter 34b in the drive voltage command calculation unit 34. First drive voltage commands Vup *, Vvp *, Vwp * superimposed on *, Vv *, Vw * are output to the voltage application unit 3.

  The voltage application unit 3 generates a three-phase AC voltage based on the first drive voltage commands Vup *, Vvp *, Vwp * and applies it to the motor 1. In this way, the motor currents iu, iv, iw detected by the current detector 4 include the high-frequency currents iuh, ivh, iwh having the same frequency components as the high-frequency voltage commands Vuh, Vvh, Vwh. Since the motor 1 has saliency, the inductance changes according to the rotor position. Therefore, the amplitudes of the high-frequency currents iuh, ivh, iwh change according to the rotor position of the motor 1.

  The coordinate converter 32 rotates the motor currents iu, iv, and iw including the high-frequency currents iuh, ivh, and iwh whose amplitudes are changed in this way, two rotation orthogonal axes that rotate in synchronization with the estimated phase θ0, that is, d. The coordinates are converted into control currents idf and iqf on the axis and q axis, and output to the filter 33.

  The filter 33 is a high-frequency current idh, having the same frequency component as the high-frequency voltage commands Vdh, Vqh inputted from the outside to the high-frequency voltage generator 30 from the control currents idf, iqf on the rotation orthogonal two axes, that is, the d-axis and the q-axis. The d-axis current id and q-axis current iq from which iqh is removed are output to the motor magnetic flux estimation unit 5b in the estimation unit 5 and the current controller 34a in the drive voltage command calculation unit 34, and the removed high-frequency currents idh, iqh is output to the motor magnetic flux estimating unit 5b in the estimating unit 5. In addition, a band pass filter and a notch filter can be illustrated as a filter used for extraction of the high-frequency currents idh and iqh.

  The estimation unit 5 includes a speed and phase estimation unit 5a and a motor magnetic flux estimation unit 5b. The motor magnetic flux estimator 5b outputs the high frequency currents idh and iqh and the control current vectors id and iq output from the filter 33 in the controller 7, and the voltage command Vd output from the current controller 34a in the drive voltage command calculator 34. Based on * and Vq *, the armature reaction estimated magnetic flux φs and the rotor estimated magnetic flux φr of the motor 1 are calculated, and the armature reaction is applied to the speed / phase estimation unit 5a and the axis deviation detection unit 6 in the estimation unit 5. The estimated magnetic flux φs is output, and the rotor estimated magnetic flux φr is output to the speed and phase estimating unit 5a in the estimating unit 5. The armature reaction is a phenomenon in which the armature current affects the magnetic flux generated by the field winding.

  Further, the speed and phase estimation unit 5a calculates the estimated phase θ0 and the estimated speed ωr0 based on the armature reaction estimated magnetic flux φs and the rotor estimated magnetic flux φr of the motor 1 output from the motor magnetic flux estimation unit 5b. Output. The estimated phase θ0 is input to the coordinate converters 32 and 34b and the high-frequency voltage generator 30 through a signal line (not shown). The estimated speed ωr0 is input to the d-axis current command calculation unit 35, the q-axis current command calculation unit 36, and the high-frequency voltage generator 30. Here, as for the estimation method, the phase estimation error correction by the high frequency superimposition method may be performed only in the low speed range, but is not limited thereto, and any method may be used as long as the position is estimated from the rotor magnetic flux of the motor 1. Various methods may be applied.

  The axis deviation detection unit 6 includes the d-axis control current vector command id * calculated and output by the d-axis current command calculation unit 35, and the motor 1 of the motor 1 calculated and output by the motor magnetic flux estimation unit 5b in the estimation unit 5. Based on the child reaction estimation magnetic flux φs and the d-axis inductance component Ld of the motor 1, an axis deviation detection signal is output. The shaft misalignment detection signal may be configured to block output or sound an alarm for notifying the user of the occurrence of shaft misalignment.

  FIG. 2 is a block diagram showing a configuration example of the axis deviation detection unit 6 shown in FIG. 2 includes an armature reaction command magnetic flux calculation unit 61 that is a calculation unit, an estimated magnetic flux alternating current component detection unit 62 that is a detection unit, and an axis shift determination unit 63 that is a determination unit. .

  The armature reaction command magnetic flux calculation unit 61 uses a multiplier to multiply the d-axis inductance component Ld of the motor 1 by the d-axis control current vector command id * to obtain the d-axis armature reaction command magnetic flux Lid *. Calculate and output.

  The estimated magnetic flux AC component detection unit 62 uses a subtractor to calculate the d-axis armature reaction estimated magnetic flux φds, which is the d-axis component of the armature reaction estimated magnetic flux φs of the motor 1, and the d-axis armature reaction command magnetic flux Ldid *. The d-axis estimated magnetic flux alternating current component φds_ac is calculated and output by subtraction. When the horizontal axis represents time and the vertical axis represents the estimated magnetic flux alternating current component, the peak width of the estimated magnetic flux alternating current component is larger than the sampling interval.

  When an axis deviation occurs, a d-axis estimated magnetic flux alternating current component φds_ac is generated. Therefore, the axial deviation of the motor 1 can be determined by a d-axis estimated magnetic flux alternating current component φds_ac that is an alternating current component of the motor magnetic flux. In the first embodiment, in order to prevent erroneous detection due to noise and other factors, an axis deviation is detected by the following determination.

  The shaft misalignment determination unit 63 determines whether or not the motor 1 is misaligned using the d-axis estimated magnetic flux alternating current component φds_ac and the shaft misalignment determination level φds_err_lv that is the shaft misalignment level signal. Specifically, the axis deviation determination unit 63 calculates the d-axis estimated magnetic flux alternating current component φds_ac by the armature reaction command magnetic flux calculation unit 61 as K = K1 and the conditional expression indicates φds_ac ≧ K1 × Ldid *. When the d-axis armature reaction command magnetic flux Ldid * is equal to or greater than the product of the coefficient K1, the shaft misalignment determining unit 63 determines that the motor 1 is misaligned. Here, the coefficient K1 is a constant satisfying 0 <K1, and the range of the value of the coefficient K1 can be exemplified by 0.25 to 0.5 so as not to be erroneously detected. The axis deviation determination unit 63 can be realized by a comparator as an example.

  Conventionally, a sudden change in the load on the motor has occurred, and the detection of the rotation stop of the motor due to an axis deviation has been performed. However, when sudden load fluctuations occur in the motor in the low speed range, the estimated phase instantaneously deviates from the actual phase by 180 degrees or 360 degrees, and an axis deviation that keeps driving the motor is detected. I couldn't. If such a state occurs continuously, the torque will be lost and no load will be applied, or if the position is controlled, the target position will not be reached. The technology to do is demanded.

  According to the first embodiment, it is possible to obtain a motor control device capable of detecting an axial deviation that continues to be driven with an estimated phase shifted by 180 degrees or 360 degrees with respect to an actual phase. For this reason, it is possible to detect the axis deviation before the problem that the axis shifts due to a steep load on the transfer device and the target position is not reached.

Embodiment 2. FIG.
In the first embodiment, saturation characteristics are not considered for the d-axis inductance component Ld input to the axis deviation detection unit 6, and an offset is added to the d-axis estimated magnetic flux alternating current component φds_ac. Therefore, in the second embodiment, the saturation characteristic of the d-axis inductance component Ld is considered.

  FIG. 3 is a block diagram illustrating a configuration example of the axis deviation detection unit 6a according to the second embodiment. The motor control device shown in FIG. 3 is obtained by replacing the shaft misalignment detection unit 6 of the motor control device according to the first embodiment with a shaft misalignment detection unit 6a. 3 includes an inductance correction unit 64 in addition to the configuration of the axis deviation detection unit 6 shown in FIG. The inductance correction unit 64 receives the control current vector commands id *, iq * and the d-axis inductance component Ld to be supplied to the motor 1, and the relationship between the q-axis control current vector command iq * and the d-axis inductance component Ld or the d-axis From the relationship between the control current vector command id * and the d-axis inductance component Ld, the d-axis inductance component Ld is corrected and the corrected d-axis inductance component Ldh is output. The armature reaction command magnetic flux calculator 61 multiplies the corrected d-axis inductance component Ldh and the d-axis control current vector command id * by using a multiplier, and d-axis armature reaction command magnetic flux Ldh · id. Calculate * and output. According to the second embodiment, the offset of the estimated magnetic flux AC component can be removed.

  The inductance correction unit 64 includes a storage unit, and stores an inductance map in the storage unit. The d-axis inductance component Ld input to the inductance correction unit 64 is an inductance when id / iq is 0 A, and the corrected d-axis inductance component Ldh is corrected using an inductance map corresponding to the value of id / iq. Do. FIG. 4 is a diagram illustrating an example of an inductance map. As an example, when id / iq is 0, when iq increases at 180 mH, the d-axis inductance component Ld attenuates and becomes 35 mH at iq = 35 A. If not corrected, a shift of 145 mH occurs. According to the inductance correction unit 64, such a deviation can be corrected.

Embodiment 3 FIG.
In the third embodiment, a motor control device including an axis deviation detection unit 6b that outputs an axis deviation detection signal on the assumption that an axis deviation has occurred only when the number of axis deviations exceeds a threshold value will be described.

  FIG. 5 is a block diagram illustrating a configuration example of the axis deviation detection unit 6b according to the third embodiment. The motor control device shown in FIG. 5 is obtained by replacing the shaft misalignment detection unit 6 of the motor control device according to the first embodiment with an shaft misalignment detection unit 6b. The axis deviation detecting unit 6b shown in FIG. 5 includes an axis deviation number measuring unit 65 and an axis deviation number comparing unit 66 in addition to the inductance correcting unit 64. The axis deviation number measuring unit 65 receives the axis deviation signal output from the axis deviation determining unit 63, measures the number of axis deviations, and outputs axis deviation number information. The axis deviation number comparison unit 66 receives the axis deviation number information, compares the axis deviation number information with the set axis deviation determination threshold number, and determines the number of axis deviations indicated by the axis deviation number information as the axis deviation. If the determination threshold value is exceeded, an axis misalignment detection signal is output because an axis misalignment has occurred. According to the third embodiment, since the axis deviation occurs when the number of occurrences of the axis deviation is equal to or greater than the set number, the detection accuracy is improved.

Embodiment 4 FIG.
In the fourth embodiment, a motor control device including an axis deviation detection unit 6c that corrects a high-frequency voltage and detects a magnetic flux estimation gain Hf when axis deviation is detected will be described. The cause of the axis deviation is the low SN ratio of the high frequency voltage and the magnetic flux estimation gain Hf due to the high frequency.

  In the motor magnetic flux estimation unit 5b, the magnetic flux of the motor is estimated by the following equations (1), (2), and (3).

  The observer gain Hc is an observer gain for performing sensorless control based on the induced voltage using an adaptive observer. The magnetic flux estimation gain Hf is an observer gain for correcting the rotor estimated magnetic flux when a high frequency is superimposed. A matrix component of the observer gain Hc and the magnetic flux estimation gain Hf is an amplification gain, and is a value that can be set by the user.

  FIG. 6 is a block diagram illustrating a configuration example of the axis deviation detection unit 6c according to the fourth embodiment. The axis deviation detection unit 6 c includes a high frequency voltage correction unit 67 and a magnetic flux estimation gain correction unit 68. When the axis deviation signal output from the axis deviation determination unit 63 is input, the high frequency voltage correction unit 67 multiplies the high frequency voltage commands Vdh and Vqh by coefficients K2 and K3. The magnetic flux estimation gain correction unit 68 multiplies the magnetic flux estimation gain Hf by a coefficient K1.

  In addition, each coefficient K1, K2, K3 is 1 or more here, and can illustrate 1.05. Since a multiplication is performed every time an axis deviation signal is input, a limit is provided. An example of this limit is twice. According to the fourth embodiment, it is possible to suppress the axial deviation.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  DESCRIPTION OF SYMBOLS 1 Motor, 2 Motor control apparatus, 3 Voltage application part, 4 Current detection part, 5 Estimation part, 5a Speed and phase estimation part, 5b Motor magnetic flux estimation part, 6, 6a, 6b, 6c Axis deviation detection part, 7 Control part , 30 high frequency voltage generator, 31 voltage adder, 32, 34b coordinate converter, 33 filter, 34 drive voltage command calculator, 34a current controller, 35 d axis current command calculator, 36 q axis current command calculator, 61 Armature reaction command magnetic flux calculation unit, 62 Estimated magnetic flux AC component detection unit, 63 Axis deviation determination unit, 64 Inductance correction unit, 65 Axis deviation number measurement unit, 66 Axis deviation number comparison unit, 67 High frequency voltage correction unit, 68 Magnetic flux Estimated gain correction unit.

Claims (6)

Estimating the motor flux is the magnetic flux of the synchronous motor, the motor flux estimator for outputting armature reaction estimated magnetic flux,
An axis deviation detection unit that detects an axis deviation based on an AC component of the motor magnetic flux obtained from the armature reaction estimation magnetic flux input from the motor magnetic flux estimation unit ;
The axis deviation detector is
An arithmetic unit that calculates an armature reaction command magnetic flux that is a magnetic flux included in the motor magnetic flux and is a magnetic flux that is generated by a current command flowing to the synchronous motor, using the current command;
Wherein said computed and armature reaction estimated magnetic flux using the armature reaction command flux, determining the AC component of the motor magnetic flux detecting unit and the motor control device Ru comprising a. The AC component is a difference between the armature reaction estimated magnetic flux and the armature reaction command magnetic flux,
The axis deviation detector is
The motor control device according to claim 1, characterized in that the front Symbol judging unit judges axis deviation by comparing the alternating current component and the axial shift level signal which is estimated by the detection unit further comprises.   3. The motor control device according to claim 1, further comprising: an inductance correction unit that receives a current command to be passed to the synchronous motor and a d-axis inductance component and outputs the corrected d-axis inductance component. An axis deviation number measurement unit that receives an axis deviation signal output from the determination unit, measures the number of axis deviations, and outputs axis deviation number information;
The axis deviation number information is input, the axis deviation number information is compared with the set axis deviation determination threshold number, and the axis deviation number indicated by the axis deviation number information is the axis deviation determination threshold value. The motor control device according to claim 2, further comprising: a shaft misalignment frequency comparison unit that outputs a shaft misalignment detection signal when a shaft misalignment occurs if the number of times is greater than or equal to the number of times. A high-frequency voltage correction unit that corrects a superimposed high-frequency voltage when the axis deviation signal is input;
A magnetic flux estimation gain correction unit that corrects the magnetic flux estimation gain when the axis deviation signal is input;
The motor control device according to claim 4, wherein the corrected high-frequency voltage and the corrected magnetic flux estimation gain are output.   6. The motor according to claim 1, wherein when the horizontal axis is time and the vertical axis is the AC component, the peak width of the AC component is larger than the sampling interval. Control device.