JP2010206946A - Sensorless controller of synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensorless controller of a synchronous motor of improving robustness against a disturbing torque and saving its power. <P>SOLUTION: Synchronous control is performed by current control with a d-axis current command id0<SP>*</SP>. For q-axis, only speed command ωre<SP>*</SP>and voltage command vqa<SP>*</SP>corresponding to phase θre<SP>*</SP>which is a positional command based on the speed command are applied, and no current control is performed in the sensorless controller of the synchronous motor. A d-axis current command calculation part 14 is provided to calculate and generate a d-axis current command id1<SP>*</SP>that increases or decreases according to an increase/decrease change amount of the detected q-axis current iqa. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sensorless control device for a synchronous motor, and more particularly to a sensorless control device for performing synchronous control in a low speed region.

  The sensorless control device when performing synchronous control in the low speed range performs synchronous control based on the d-axis current command from the servo controller, and according to the speed command from the servo controller and the position command obtained from it for the q-axis Only a voltage command is applied, and current control is not performed. For this reason, conventionally, the d-axis current command given to the sensorless control device has a fixed value (for example, a value of about the rated current) so that a starting torque commensurate with the actual machine can be obtained even when stopped (for example, a non-current value). Patent Document 1).

"Sensorless speed control of IPM motor" 1999 IEEJ Industrial Application Conference No. 189 pp. 51-56

  However, the conventional sensorless control device that gives a fixed-value d-axis current command has a problem in that wasteful power consumption occurs at light loads, and the motor does not step out and rotate at high loads.

  Further, in order to prevent rotation due to a disturbance load at the time of stopping, it has been necessary to adopt position control or to always give a useless d-axis current command.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a sensorless control device for a synchronous motor capable of improving robustness against disturbance torque and saving power.

  In order to achieve the above-described object, the present invention performs synchronous control by current control based on a d-axis current command, and applies only a voltage command corresponding to a speed command and a position command based on the current command to the q-axis. In a sensorless control device for a synchronous motor that is not controlled, a d-axis current command calculation unit that calculates and generates the d-axis current command that increases or decreases in accordance with an increase or decrease in the detected change amount of the q-axis current is provided. It is characterized by.

  According to the present invention, it is possible to calculate and generate a d-axis current command so as to generate a torque for returning the rotor to the original by using a change amount of the q-axis current that is generated due to the axis deviation caused by the application of disturbance torque. Therefore, even if a high d-axis current command is not given in advance, step-out can be avoided, robustness against disturbance torque can be improved, and power saving can be achieved at the same time.

FIG. 1 is a block diagram showing a configuration of a sensorless control device for a synchronous motor according to an embodiment of the present invention. 2, d-axis is a motor shaft of the synchronous motor shown in Fig. 1, d ^* axis and q-axis and the control axis, when the the q ^* axes are matched, the d ^* axis at a specified speed? Re ^* It is a figure explaining the state to rotate. FIG. 3 is a diagram for explaining a rotation state when there is a phase error θerr between the command speed ωre ^* and the rotor speed ωre in FIG. FIG. 4 is a block diagram illustrating a configuration example (part 1) of the d-axis current command calculation unit illustrated in FIG. FIG. 5 is a diagram showing an example of variable gain characteristics for explaining the configuration and operation of the variable gain section shown in FIG. FIG. 6 is a diagram for explaining the operation of the d-axis current command calculation unit shown in FIGS. 4, 7, and 8. FIG. 7 is a block diagram illustrating a configuration example (No. 2) of the d-axis current command calculation unit illustrated in FIG. 1. FIG. 8 is a block diagram illustrating a configuration example (No. 3) of the d-axis current command calculation unit illustrated in FIG. 1. FIG. 9 is a block diagram illustrating a configuration example (No. 4) of the d-axis current command calculation unit illustrated in FIG. 1. FIG. 10 is a diagram for explaining the operation of the d-axis current command calculation unit shown in FIGS. 9, 11, and 12. FIG. 11 is a block diagram illustrating a configuration example (No. 5) of the d-axis current command calculation unit illustrated in FIG. 1. FIG. 12 is a block diagram illustrating a configuration example (No. 6) of the d-axis current command calculation unit illustrated in FIG. 1.

  Embodiments of a sensorless control device for a synchronous motor according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a block diagram showing a configuration of a sensorless control device for a synchronous motor according to an embodiment of the present invention. In FIG. 1, a synchronous motor 50 is a permanent magnet synchronous motor. In the present embodiment, a non-saliency surface magnet synchronous motor is used as the synchronous motor 50.

  In general, a sensorless control device that synchronously controls the synchronous motor 50 in a low speed range includes a speed command generation unit 1, a speed calculation unit 2, a phase calculation unit 3, a d-axis current control unit 4, and an induced voltage compensation unit 5. A decoupling control unit 6, adders 7 and 8, a three-phase two-phase coordinate conversion unit 9, a two-phase three-phase coordinate conversion unit 10, a power converter 11, and current detectors 12 and 13. It has.

  The sensorless control device according to the present embodiment is obtained by adding a d-axis current command calculation unit 14 and an adder 15 to the above configuration. Note that the adder 15 is an output circuit of the d-axis current command calculation unit 14, but is extracted and shown for easy understanding.

That is, the d-axis current command id0 ^* is input from a servo controller (not shown), but is generally input directly to the d-axis current control unit 4. In contrast, in the present embodiment, the adder 15 adds the d-axis current command id1 ^* calculated by the d-axis current command calculation unit 14 as described later to the d-axis current command id0 ^*. The current command ida ^* is input to the d-axis current control unit 4. D-axis current command in this case id1 ^* is a d-axis current command for adjustment.

Here, the d-axis current command id0 ^* from the servo controller is generally a fixed value such as a rated current as described above. However, the d-axis current command id0 ^* referred to in the present embodiment is a commonly used solid. A value lower than the value may be used. Specifically, it may be a very small value required as a holding torque at the time of stop when a stop command is output from the servo controller. Such a low value can be set manually.

However, in the present invention, theoretically, the d-axis current command calculation unit 14 can determine the d-axis current command necessary for the current control performed by the d-axis current control unit 4. id0 ^* may be zero. Therefore, the principle configuration of the present invention is the d-axis current according to the present invention in which there is no adder 15 in FIG. 1 and the d-axis current command id1 ^* for adjustment output from the d-axis current command calculation unit 14 is not for adjustment. The command is input to the d-axis current control unit 4 as the command ida ^* .

However, when the d-axis current command id0 ^* from the servo controller to zero, in practical applications, even appear q-axis current iqa to change component from the three-to-two phase converter 9 by the application of weak disturbance torque, Since the amount of change is small, it is conceivable that the change component due to the weak disturbance torque is removed by the filter in the d-axis current command calculation unit 14. Then, it becomes impossible to detect the application of disturbance torque, and the rotor magnet of the synchronous motor 50 may be rotated by the weak disturbance torque. In order to avoid such a situation, it is necessary to supply a d-axis current command of a certain size in advance as in the conventional case. Therefore, in the present embodiment, as shown in FIG. 1, an adder 15 is provided, and the d-axis current command id0 ^* having the above-described contents is input from the servo controller.

First, the operation of each part in a general configuration will be briefly described. The d-axis current control unit 4 applies d to the d-axis of the synchronous motor 50 based on the d-axis current command id0 ^* from the servo controller and the detected d-axis current ida from the three-phase two-phase coordinate conversion unit 9. to generate the axis voltage vd ^*. The d-axis voltage vd ^* is added to the d-axis interference voltage vdo ^* output from the non-interacting control unit 6 by the adder 8 to obtain a d-axis voltage vda ^* , which is input to the two-phase / three-phase coordinate conversion unit 10. Is done.

Further, the speed command generator 1 generates a speed command ωr ^* that specifies the rotational speed of the synchronous motor 50 in accordance with the speed command ωr from the servo controller. The speed calculation unit 2 multiplies the speed command ωr ^* , which is the mechanical speed generated by the speed command generation unit 1, by the counter electrode number P / 2 (P is the total number of poles), and is represented by an electrical angle. The speed command ωre ^* is calculated. This speed command ωre ^* is input to the phase calculation unit 3, the induced voltage compensation unit 5, and the non-interacting control unit 6.

The phase calculating unit 3 integrates the speed command? Re ^* and calculates the phase [theta] re ^* on the motor shaft (dq). This phase θre ^* is input to the three-phase two-phase coordinate conversion unit 9 and the two-phase three-phase coordinate conversion unit 10 as a position command.

The induced voltage compensator 5 calculates an induced voltage vq ^* that is generated when the synchronous motor 50 rotates at the speed command ωre ^* . The induced voltage vq ^* is a voltage for compensating the q-axis voltage for the speed command? Re ^*, by the adder 7, the q-axis interference voltage Vqo ^* is added q-axis voltage non-interference control section 6 outputs vqa ^* is input to the two-phase / three-phase coordinate conversion unit 10. Here, the induced voltage vq ^* is expressed by the following equation (1) using the magnetic flux density Φa when the synchronous motor 50 is a non-salient surface magnet motor.
vq ^* = ωre ^* × Φa (1)

The two-phase three-phase coordinate conversion unit 10 synchronizes the control two-phase voltages (d-axis voltage vda ^* , q-axis voltage vqa ^* ) between the d-axis and the q-axis orthogonal thereto based on the phase θre ^* that is a position command. It is converted into a three-phase (UVW) voltage command (vaa ^* , vva ^* , vwa ^* ) to be applied to the electric motor 50. The power converter 11 is a so-called inverter, and is switched by a drive pulse signal subjected to pulse width modulation generated based on a three-phase voltage command (vaa ^* , vva ^* , vwa ^* ) from the two-phase / three-phase coordinate conversion unit 10. The element is turned on / off to generate a three-phase AC voltage having a frequency corresponding to the speed command ωre ^* and supplied to the synchronous motor 50. In the illustrated example, the current detectors 12 and 13 detect U-phase and V-phase drive currents iua and iva at this time and input them to the three-phase two-phase coordinate conversion unit 9.

The three-phase two-phase coordinate conversion unit 9 calculates the remaining one phase (in this example, the W-phase drive current iwa) from the two-phase drive currents (iua, iva) input from the current detectors 12 and 13. and generates a driving current of the three phases, it is converted into a control current of two phases of the d-axis and q-axis based on the phase [theta] re ^* is a position command (d-axis current ida, q-axis current iqa). The converted d-axis current ida and q-axis current iqa are input to the non-interacting control unit 6, and the converted d-axis current ida is input to the d-axis current control unit 4. The d-axis current control unit 4 has been described above.

The non-interacting control unit 6 compensates the d-axis voltage and the q-axis voltage against interference using the speed command ωre ^* , which is an interference term, and the detected d-axis current ida and q-axis current iqa. An axial interference voltage vdo ^* and a q-axis interference voltage vqo ^* are calculated and generated. The generated d-axis interference voltage vdo ^* is input to the adder 8, the q-axis interference voltage Vqo ^* is input to the adder 7 as described above. Here, the d-axis interference voltage vdo ^* and the q-axis interference voltage vqo ^* are expressed by the following equations (2) and (3) when the synchronous motor 50 is a non-salient surface magnet motor. In equations (2) and (3), La is the inductance component of the d axis and q axis.
vdo * = − ωre ^* · La · iqa (2)
vqo * = ωre ^* · La · iqa (3)

As described above, the sensorless control device when performing synchronous control in the low speed region performs synchronous control based on the d-axis current command id0 ^* from the servo controller, and for the q-axis, from the speed command ωr from the servo controller. Only the voltage command (vqa ^* ) corresponding to the generated speed command ωre ^* and the phase θre ^* which is a position command obtained from the generated velocity command ωre ^* is applied, and current control is not performed.

Now, FIG. 2, d-axis is a motor shaft of the synchronous motor shown in FIG. 1, if d ^* axis and q-axis and the control axis, and the q ^* axes are matched, d ^* axis velocity command to ωre It is a figure explaining the state rotated according to ^* . FIG. 3 is a diagram for explaining a rotation state when there is a phase error θerr between the speed command ωre ^* and the rotor speed ωre in FIG.

As shown in FIG. 2, the d ^* axis of the control shaft is rotated according to the speed command? Re ^*, when rotating the rotor magnet 21 speed command? Re ^* the direction of the control shaft by the disturbance torque of friction If a shift in the d-axis of the d ^* axis and the motor shaft occurs, as shown in FIG. 3, the phase error θerr occurs and the speed command? re ^* and the rotor speed? re.

As described above, the q-axis current control is not performed, and the induced voltage compensator 5 calculates the q-axis voltage vq ^* calculated according to the electrical angle speed command ωre ^* , and the non-interacting controller 6 detects the q-axis current iqa. when applied to the synchronous motor 50 is given to the q-axis voltage VQA ^* a two-to-three phase coordinate converter 9 and a calculated q-axis interference voltage Vqo ^* obtained by adding by the adder 7 by using, q-axis of the motor shaft A voltage error corresponding to the phase error θerr is generated in the actual applied voltage vqa ^* and the applied voltage vqa obtained as a theoretical value, and the voltage is applied to the q-axis current iqa output from the three-phase two-phase coordinate converter 9. A change component having a magnitude corresponding to the error appears.

  Hereinafter, the case of a surface magnet motor having a non-salient pole will be described in detail. In the case of a non-saliency surface magnet motor, the relationship between the d-axis voltage vda and the q-axis voltage vqa is expressed by the voltage equation shown in the following equation (4). In Equation (4), Ra is a winding resistance and p is a differential symbol.

From the above equation (4), the applied q-axis voltage vqa ^* and the applied voltage vqa obtained as a theoretical value are expressed as the following equations (5) and (6). The voltage error vqe generated on the q axis is expressed as Expression (7) from Expressions (5) and (6).
vqa ^* = ωre ^* · La · ida + (Ra + pLa) iqa + ωre ^* · Φa (5)
vqa = ωre · La · ida · cosθerr
+ (Ra + pLa) iqa · cos θerr + ωre · Φa · cos θerr (6)
vqe = vqa ^* -vqa
= (Ωre ^* −ωre · cos θerr) (La · ida + Φa) (7)

Here, focusing on the q-axis, when speed command (ωre ^* ) − rotor speed (ωre) × cos θerr = 0, no voltage error (vqe) occurs and q-axis current (iqa) is not detected. When the speed command (ωre ^* ) − rotor speed (ωre) × cos θerr ≠ 0, the voltage error (vqe) becomes vqe ≠ 0, and the q-axis current (iqa) is detected. At the time of stop, ωre ^* = 0, and when the rotor magnet 21 is rotated by disturbance torque and a voltage error (vqe) occurs, the q-axis current (iqa) is similarly detected. The

  Conventionally, there is no means for monitoring the change in the q-axis current iqa output by the three-phase / two-phase coordinate conversion unit 9 and feeding it back to the d-axis current control, so the rotor magnet 21 is rotated by disturbance torque. Even it could not be detected and corrected.

Therefore, in the present embodiment, as shown in FIG. 1, a d-axis current command calculation unit 14 including an adder 15 is provided as the above means. The d-axis current command calculation unit 14 takes in the detected q-axis current iqa converted and output by the three-phase two-phase coordinate conversion unit 9 that has been used only for the interference control in the past, and monitors the amount of change in the q-axis current iqa. , calculates the d-axis current command id1 ^* to increase or decrease adjust the d-axis current command ido ^* from the servo controller, adder 15 d-axis current command and automatically increases or decreases adjusting the d-axis current command ido ^* from ida ^* is d It is configured to be output to the shaft current control unit 4. As a result, the d-axis current control unit 4 can generate an appropriate d-axis voltage vd ^* with improved robustness against disturbance torque.

  The d-axis current command calculation unit 14 can be configured in various modes as shown in FIGS. 4, 7 to 9, 11, and 12, for example. Hereinafter, the configuration and operation of the d-axis current command calculation unit 14 including the adder 15 will be described in the order of the figure numbers.

(Configuration example of d-axis current command calculation unit 14 (part 1))
FIG. 4 is a block diagram illustrating a configuration example (part 1) of the d-axis current command calculation unit illustrated in FIG. As shown in FIG. 4, the d-axis current command calculation unit 14 shown in FIG. 1 includes a band-pass filter 31 to which the detected q-axis current iqa is input, and an absolute value circuit that receives the output of the band-pass filter 31 as an input. (ABS) 32, a time constant variable filter 33 that receives the output of the absolute value circuit 32, and an output gain multiplier 34 that receives the output of the time constant variable filter 33. The output of the output gain multiplier 34 is input to one input terminal of the adder 15. The d-axis current command 1d0 ^* from the servo controller is input to the other input terminal of the adder 15.

  The band-pass filter 31 includes two low-pass filters 35 and 36 having different time constants to which the detected q-axis current iqa is input in parallel, and an adder / subtracter 37 to which outputs of the two low-pass filters 35 and 36 are input. The noise component and the steady deviation component included in the q-axis current iqa are removed from the adder / subtractor 37 to the absolute value circuit 32, and the q-axis current iqa having only a change component that changes positively and negatively is output. .

  The absolute value circuit 32 generates an absolute value q-axis current iqb in which the change component of the q-axis current iqa that changes from positive to negative input from the bandpass filter 31 is converted into an absolute value and the polarity is aligned on the positive electrode side. Output to the constant variable filter 33.

  The time constant variable filter 33 includes an adder / subtractor 39, a variable gain unit 40, a multiplier 41, and an integrator 42. The adder / subtractor 39 subtracts the state quantity iqf of the time constant variable filter 33, which is the current integrated value of the integrator 42, from the absolute value q-axis current iqb from the absolute value circuit 32 to obtain a deviation iqe. Is output to the variable gain unit 40 and one input terminal of the multiplier 41. The output Gout of the variable gain unit 40 is input to the other input terminal of the multiplier 41. The output of the multiplier 41 is input to the integrator 42.

  The variable gain unit 40 is a circuit that makes the gain of the output Gout variable according to the magnitude of the input deviation iq. FIG. 5 is a diagram showing an example of variable gain characteristics for explaining the configuration and operation of the variable gain unit shown in FIG. For example, as illustrated in FIG. 5, the variable gain unit 40 outputs the output Gout with a large gain when the deviation iq is large, and outputs the output Gout with a small gain when the deviation iq is small. .

The relationship between the deviation iq and the output Gout in the variable gain unit 40 shown in FIG. 5 is expressed by the following equations (8) and (9). However, in FIG. 5, G0 is a gain value at the time of the deviation threshold value iq0, for example, 1 [rad / sec]. G1 is a gain value at the time of the deviation threshold value iq1, for example, 4000 [rad / sec].
When iq <iq0 Gout = G0 (8)
When iq ≧ iq0 Gout = {(G1-G0) / (iq1-iq0)}
× (iq−iq0) + G0 (9)

  In the time constant variable filter 33, the deviation iq output from the adder / subtractor 39 and the output Gout of the variable gain unit 40 are multiplied by the multiplier 41, input to the integrator 42, and accumulated in the state quantity iqf. Due to the above-described operation of the variable gain unit 40, the value accumulated in the state quantity iqf becomes variable, and the time constant differs depending on whether the state quantity iqf increases or decreases.

The output gain multiplier 34 generates the d-axis current command id1 ^* by multiplying the state quantity iqf that increases or decreases with a different time constant according to the deviation iq by the output gain Kq. Adder 15, an output gain multiplier 34 generated by the d-axis current command id1 ^* and the d-axis current command ida of d-axis current command from the servo controller id0 ^* and adds the the d-axis current controller 4 ^* To do.

Next, the operation of the d-axis current command calculation unit shown in FIG. 4 will be described with reference to FIG. FIG. 6 is a waveform diagram for explaining the operation of the d-axis current command calculation unit shown in FIGS. 4, 7, and 8. In Figure 6, the disturbance torque, and the detected q-axis current iqa, the absolute value q-axis current Iqb, calculating the resulting d-axis current command id1 ^* relationship with are shown.

In FIG. 6, when a disturbance torque is applied, the rotor magnet 21 is rotated in a direction away from the d ^* axis as shown in FIG. The q-axis current iqa that greatly changes from the phase conversion unit 9 is input to the d-axis current command calculation unit 14 shown in FIG.

  In the d-axis current command calculation unit 14, such a large change component of the q-axis current iqa is extracted by the band pass filter 31. In the illustrated example, since the q-axis current iqa detected first is positive, it is output from the absolute value circuit 32 as it is to the time constant variable filter 33 as the absolute value q-axis current iqb.

In the time constant variable filter 33, the d-axis current command id1 ^* is rapidly increased with a small time constant in response to an increase in the input absolute value q-axis current iqb. The d-axis current command id1 ^* that changes in this way is added to the d-axis current command id0 ^* from the servo controller by the adder 15 and is input to the d-axis current control unit 4, and the corresponding d-axis voltage vd ^* is obtained. Is generated and applied to the synchronous motor 50.

This d-axis current command id1 ^* generates a torque for returning the rotor magnet 21 in the d ^* -axis direction. When the d-axis current command id1 ^* rises to a certain level, the torque for returning the rotor magnet 21 in the d ^* -axis direction. Overcomes the disturbance torque, and the rotor speed changes in the d ^* -axis direction. As the change in the rotor speed with respect to the d ^* axis becomes smaller, the voltage error is eliminated and the q-axis current iqa and the absolute value q-axis current iqb become smaller. Therefore, in the time constant variable filter 33, the absolute value q-axis In response to the decrease in current iqb, the d-axis current command id1 ^* is decreased with a large time constant. The d-axis current command id1 ^* that changes in this way is added to the q-axis current command iq0 ^* from the servo controller.

When the disturbance torque in the process is eliminated, the rotor speed by the torque back to d ^* axial direction that is generated by the d-axis current command id1 ^*, since changes to d ^* axial direction, again, the change of the induced voltage Occurs, and a second q-axis current iqa is generated. Since the polarity of the induced voltage in this case is opposite to that when the disturbance torque is applied, the generated second q-axis current iqa is negative in this example. This negative q-axis current iqa becomes a positive absolute q-axis current iqb in the absolute value circuit 32 and is input to the time constant variable filter 33.

In the time constant variable filter 33, similarly to the above, steeply increases in a small time constant the d-axis current command id1 ^*. When the rotor speed does not change with respect to the d ^* axis, the second q-axis current iqa decreases and the absolute value q-axis current iqb decreases, the time constant variable filter 33 again causes the d-axis current command id1. ^* Decrease slowly with a large time constant to zero.

Thus, the d-axis current command calculating unit 14 shown in FIG. 4, the d-axis current command id0 ^* from the servo controller automatically determines the increase or decrease adjustment to d-axis current command id1 ^* according to the disturbance torque, running Therefore, it is possible to eliminate the axis deviation due to the disturbance torque, and to improve the robustness against the disturbance.

Conventionally, in order to prevent an axis deviation due to disturbance torque, in the example shown in FIG. 6, the peak value of the d-axis current command id1 ^* is always supplied in a fixed manner. On the other hand, in the present embodiment, as shown in FIG. 6, the d-axis current command id1 ^* is zero when the disturbance torque is not applied, and the d-axis current is even when the disturbance torque is applied. Since the command id1 ^* is not fixed to a large value and increases or decreases, the power consumption can be reduced as compared with the conventional case.

On the other hand, it can be understood from the explanation of the operation shown in FIG. 6 that the d-axis current command id0 ^* , which has been conventionally required, can be made unnecessary in the present invention.

(Configuration example of d-axis current command calculation unit 14 (part 2))
FIG. 7 is a block diagram illustrating a configuration example (No. 2) of the d-axis current command calculation unit illustrated in FIG. 1. In FIG. 7, in the configuration shown in FIG. 4, a low-pass filter 43 is provided instead of the band-pass filter 31.

That is, in the d-axis current command calculation unit 14 shown in FIG. 7, the low-pass filter 43 extracts a change component of the q-axis current iqa by excluding a noise component from the detected q-axis current iqa, and calculates it as an absolute value. An absolute value is converted into an absolute value q-axis current iqb by the circuit 32. Thereafter, as described with reference to FIG. 4, the time constant variable filter 33 is configured to increase or decrease the state quantity iqf with different time constants according to the deviation iq between the absolute value q-axis current iqb and the state quantity iqf. The output gain multiplier 34 generates a d-axis current command id1 ^* obtained by multiplying the state quantity iqf by the output gain Kq, and the adder 15 generates the d-axis current command id1 ^* and the d-axis current from the servo controller. The command id0 ^* is added and a d-axis current command id0 ^* used by the d-axis current control unit 4 is output.

Even with this configuration, during a disturbance, the same operation as described in FIG. 6 is performed, and the axis deviation can be eliminated by automatically increasing / decreasing the d-axis current command id0 ^* from the servo controller. Robustness is improved. Similarly, power saving can be achieved.

(Example of configuration of d-axis current command calculation unit 14 (part 3))
FIG. 8 is a block diagram illustrating a configuration example (No. 3) of the d-axis current command calculation unit illustrated in FIG. 1. In FIG. 8, the bandpass filter 31 is deleted in the configuration shown in FIG.

That is, in the d-axis current command calculation unit 14 shown in FIG. 8, the detected q-axis current iqa is directly input to the absolute value circuit 32 and becomes an absolute value q-axis current iqb. The subsequent time constant variable filter 33, output gain multiplier 34, and adder 15 perform the operations described with reference to FIG. Even with this configuration, the operation similar to that described with reference to FIG. 6 is performed in the event of a disturbance, and the d-axis current command id0 ^* from the servo controller can be automatically increased or decreased to eliminate the axis deviation. Improves. Similarly, power saving can be achieved.

(Example of configuration of d-axis current command calculation unit 14 (part 4))
FIG. 9 is a block diagram illustrating a configuration example (No. 4) of the d-axis current command calculation unit illustrated in FIG. 1. In FIG. 9, in the configuration shown in FIG. 4, a time constant fixed filter 45 is provided instead of the time constant variable filter 33. The time constant fixed filter 45 is different from the time constant variable filter 33 shown in FIG. 4 in that an integral gain multiplier 46 is provided between the adder / subtractor 39 and the integrator 42 instead of the variable gain unit 40 and the multiplier 41. Yes.

That is, in the d-axis current command calculation unit 14 shown in FIG. 9, the band-pass filter 31 extracts a change component of the q-axis current iqa by excluding a noise component and a steady deviation from the detected q-axis current iqa. The absolute value is converted into an absolute value by the absolute value circuit 32 to obtain an absolute value q-axis current iqb. In the time constant fixed filter 45, the adder / subtractor 39 obtains the deviation iq between the absolute value q-axis current iqb and the state quantity iqf, and the deviation iq is multiplied by the integral gain Ki in the integral gain multiplier 46. The deviation is input to the integrator 42 and integrated with the state quantity iqf, thereby generating a state quantity iqf that increases or decreases with the same time constant according to the deviation iqe. Then, the output gain multiplier 34 generates a d-axis current command id1 ^* obtained by multiplying the state quantity iqf by the output gain Kq, and the adder 15 generates the d-axis current command id1 ^* and the d-axis current command from the servo controller. The id0 ^* is added and the d-axis current command id0 ^* used by the d-axis current control unit 4 is output.

Next, the operation will be described with reference to FIG. FIG. 10 is a waveform diagram for explaining the operation of the d-axis current command calculation unit shown in FIGS. 9, 11, and 12. In Figure 10, similarly to FIG. 6, the disturbance torque, and the detected q-axis current iqa, the absolute value q-axis current Iqb, calculating the resulting d-axis current command id1 ^* relationship with are shown.

In FIG. 10, when a disturbance torque is applied, the rotor magnet 21 is rotated in a direction away from the d ^* axis as shown in FIG. The q-axis current iqa that varies greatly from the converter 6 is input to the d-axis current command calculator 14 shown in FIG.

  In the d-axis current command calculation unit 14, such a large change component of the q-axis current iqa is extracted by the band pass filter 31. In the illustrated example, since the detected q-axis current iqa is positive, it is output from the absolute value circuit 32 to the time constant variable filter 33 as it is as the absolute value q-axis current iqb.

In the time constant variable filter 33, increases were d-axis current command id1 and ^* response to rising transition of the absolute value q-axis current Iqb. The d-axis current command id1 ^* that changes in this way is added to the d-axis current command id0 ^* from the servo controller by the adder 15 and is input to the d-axis current control unit 4, and the corresponding d-axis voltage vd ^* is obtained. Is generated and applied to the synchronous motor 50.

This d-axis current command id1 ^* generates a torque for returning the rotor magnet 21 in the d ^* -axis direction. When the d-axis current command id1 ^* rises to a certain level, the torque for returning the rotor magnet 21 in the d ^* -axis direction. Overcomes the disturbance torque, and the rotor speed changes in the d ^* -axis direction. As the change in the rotor speed with respect to the d ^* axis becomes smaller, the voltage error is eliminated and the q-axis current iqa and the absolute value q-axis current iqb become smaller. Therefore, in the time constant fixed filter 45, the absolute value q-axis In response to the decrease in current iqb, the d-axis current command id1 ^* is decreased with a time constant having the same magnitude as that when increasing. The d-axis current command id1 ^* that changes downward is added to the d-axis current command id0 ^* from the servo controller.

When the d-axis current command id1 ^* is lowered during the disturbance torque application, the induced voltage is changed again, and the q-axis current iqa is generated. Since the polarity of the induced voltage in this case is opposite to that when the disturbance torque is applied, the generated q-axis current iqa is negative in this example. This negative q-axis current iqa becomes a positive absolute q-axis current iqb in the absolute value circuit 32 and is input to the time constant fixed filter 45.

In the time constant fixed filter 45, as described above, the d-axis current command id1 ^* is increased by a time constant having the same magnitude as the previous time. The above operation is repeated until the disturbance torque disappears. After the disturbance torque disappears, when the change in the rotor speed with respect to the d ^* axis disappears, the time constant fixed filter 45 lowers the d-axis current command id1 ^* again with a time constant having the same magnitude as that when increasing, Set to zero.

Thus, the axial current calculation unit 14 illustrated in FIG. 9, the d-axis current command id0 ^* from the servo controller automatically determines the increase or decrease adjustment to d-axis current command id1 ^* according to the disturbance torque, execute Therefore, the shaft misalignment due to the disturbance torque can be eliminated, and the robustness against the disturbance torque can be improved. Similarly, power saving can be achieved.

(Example of configuration of d-axis current command calculation unit 14 (part 5))
FIG. 11 is a block diagram illustrating a configuration example (No. 5) of the d-axis current command calculation unit illustrated in FIG. 1. In FIG. 11, in the configuration shown in FIG. 9, a low pass filter 43 is provided instead of the band pass filter 31.

That is, in the d-axis current command calculation unit 14 shown in FIG. 11, the low-pass filter 43 extracts a change component of the q-axis current iqa by excluding a noise component from the detected q-axis current iqa, and calculates the absolute value thereof. An absolute value is converted into an absolute value q-axis current iqb by the circuit 32. Thereafter, as described with reference to FIG. 9, the time constant fixed filter 45 generates the state quantity iqf to change with the same time constant according to the deviation iq between the absolute value q-axis current iqb and the state quantity iqf. The output gain multiplier 34 generates a d-axis current command id1 ^* obtained by multiplying the state quantity iqf by the output gain Kq, and the adder 15 generates the d-axis current command id1 ^* and the d-axis current command from the servo controller. The id0 ^* is added and a d-axis current command ida ^* used by the d-axis current control unit 4 is output.

Even with this configuration, during a disturbance, the same operation as described in FIG. 6 is performed, and the axis deviation can be eliminated by automatically increasing / decreasing the d-axis current command id0 ^* from the servo controller. Robustness against disturbance torque is improved. Similarly, power saving can be achieved.

(Example of configuration of d-axis current command calculation unit 14 (6))
FIG. 12 is a block diagram illustrating a configuration example (No. 6) of the d-axis current command calculation unit illustrated in FIG. 1. In FIG. 12, the bandpass filter 31 is deleted in the configuration shown in FIG.

That is, in the d-axis current command calculation unit 14 shown in FIG. 12, the detected q-axis current iqa is directly input to the absolute value circuit 32 and becomes an absolute value-ized q-axis current iqb. The subsequent time constant fixing filter 45, output gain multiplier 34, and adder 15 perform the operations described with reference to FIG. Even with this configuration, the operation similar to that described in FIG. 10 is performed during disturbance, and the d-axis current command id0 ^* from the servo controller can be automatically increased or decreased to eliminate the axis deviation. Robustness against disturbance torque is improved. Similarly, power saving can be achieved.

As described above, according to the present embodiment, the d-axis current command id0 ^* is automatically set using the change amount of the q-axis current generated due to the axis deviation caused when the disturbance torque is applied. Since a d-axis current command calculation unit that can determine the d-axis current command id1 ^* to be increased or decreased is provided, step-out can be avoided even if a high d-axis current command id0 ^* is not given in advance, and robust against disturbance Performance can be improved, and power saving can be achieved.

In addition, it is not necessary to continue to provide the d-axis current command id0 ^* even when stopped, and it becomes possible to automatically flow the necessary d-axis current only when torque is required, so that power consumption is kept low, Control with less heat generation is possible.

In addition, in the d-axis current command calculation unit, when using a time constant variable filter that can generate the d-axis current command id1 ^* to be determined so as to change with different time constants at the time of increase and decrease, a steep disturbance load is used. D-axis current command id1 ^* can be created.

  As described above, the sensorless control device for a synchronous motor according to the present invention is useful as a sensorless control device capable of improving robustness against disturbance torque and saving power, and is particularly suitable for a sensorless control device in a low speed region. ing.

DESCRIPTION OF SYMBOLS 1 Speed command generation part 2 Speed calculation part 3 Phase calculation part 4 d-axis current control part 5 Induced voltage compensation part 6 Decoupling control part 7, 8 Adder 9 3 phase 2 phase coordinate conversion part 10 2 phase 3 phase coordinate conversion Unit 11 Power converter 12, 13 Current detector 14 d-axis current command calculation unit 15 Adder 21 Rotor magnet 31 Band pass filter 32 Absolute value circuit 33 Time constant variable filter 34 Output gain multiplier 35, 36 Low pass filter 37, 39 Adder / Subtractor 40 Variable Gain Unit 41 Multiplier 42 Integrator 43 Low-pass Filter 45 Time Constant Fixed Filter 46 Integral Gain Multiplier 50 Synchronous Motor

Claims (5)

A sensorless control device for a synchronous motor that performs synchronous control by current control using a d-axis current command and applies only a voltage command corresponding to a speed command and a position command based on the speed command and does not perform current control for the q-axis. In
A d-axis current command calculation unit that calculates and generates the d-axis current command that increases or decreases according to an increase or decrease in the detected change amount of the q-axis current;
A sensorless control device for a synchronous motor, comprising: A sensorless control device for a synchronous motor that performs synchronous control by current control using a d-axis current command and applies only a voltage command corresponding to a speed command and a position command based on the speed command and does not perform current control for the q-axis. In
A d-axis current command calculation unit for calculating and generating an adjustment d-axis current command for increasing or decreasing the d-axis current command based on the detected change amount of the q-axis current;
A sensorless control device for a synchronous motor, comprising: The d-axis current command calculation unit is
An absolute value circuit that aligns the detected direction change polarity of the q-axis current with one polarity; and
A filter that converts a current signal that changes in one polarity output by the absolute value circuit into a current signal that increases and decreases with a predetermined time constant according to the rate of increase and decrease, and
An output gain multiplier that multiplies the current signal output by the filter by an output gain to output the d-axis current command or the adjustment d-axis current command;
The sensorless control device for a synchronous motor according to claim 1, comprising:   The filter is configured to give different time constants or the same time constant to the increase change rate and the decrease change rate as the predetermined time constant, respectively. The sensorless control device for a synchronous motor according to claim 3, wherein:   The sensorless control apparatus for a synchronous motor according to claim 3 or 4, wherein a band pass filter or a low pass filter is provided at an input stage of the absolute value circuit.

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