JP2022123713A - motor controller - Google Patents

Abstract

To prevent, in detection of the position of a magnetic pole of a motor for a control axis configured to be applied with an unbalanced load, an unnecessary motion of a movable element of the motor, and reduce the time required for the detection of the position of the magnetic pole as much as possible.SOLUTION: A motor controller has a feedback system including a plurality of controllers that receive input of feedback signals related to the movement of a motor for a control axis configured to be applied with a predetermined unbalanced load, and executes first processing of increasing, with a current control unit, control current forming a driving force in the same phase as the phase of the control current, while maintaining a balanced state between the predetermined unbalanced load and the driving force, and second processing of calculating the position of the magnetic pole of the motor based on a displacement amount in which a movable element is displaced through the first processing and the control current increased in the first processing.SELECTED DRAWING: Figure 6

Description

The present invention relates to a motor control device.

Permanent magnet synchronous motors are becoming more popular due to their advantages such as high efficiency and space saving, and are widely used not only as rotary motors but also as linear motors. A permanent magnet synchronous type rotary motor has problems such as being unable to generate torque unless a voltage is applied according to the magnetic pole position of a mover (rotor) having permanent magnets. is important. In a permanent magnet type linear motor, the permanent magnet is generally placed on the stator side. voltage must be applied. As is well known, if an encoder is used, it is possible to calculate the speed and magnetic pole position of the motor based on the position signal that is its output signal. Since the position is unknown, it is necessary to accurately detect this initial magnetic pole position and start stably.

In addition, when an unbalanced load is applied to the mover of the motor, the mover is displaced by the unbalanced load. Therefore, the magnetic pole position must be detected in consideration of the influence of the unbalanced load. For example, in the device disclosed in Patent Document 1, currents of four phases are applied centering on the reference phase of the field phase determined by the excitation current flowing through the armature coil of the synchronous motor, and the angular velocity of the rotor at each is The magnetic pole position of the motor is calculated based on.

JP-A-2002-247881

According to the technique disclosed in Patent Document 1, it is necessary to apply four types of current and detect the angular velocity of the rotor in each of them. It is necessary to use a braking force with a braking means such as a brake each time switching is performed. Therefore, the time required to detect the magnetic pole position of the motor becomes long. Further, if the mover is displaced many times during the detection of the magnetic pole position, it leads to unnecessary displacement of the load device connected to the mover, which is not preferable. In particular, in a configuration where an unbalanced load is applied, the mover is likely to be accelerated by the unbalanced load, so it is preferable to suppress unnecessary displacement of the mover as much as possible in detecting the magnetic pole position.

The present invention has been made in view of such problems, and suppresses unnecessary movement of a mover of the motor when detecting the magnetic pole position of the motor for a control shaft configured to apply an unbalanced load, and An object of the present invention is to provide a technique for shortening the time required for detecting the magnetic pole position as much as possible.

A motor control device according to one aspect of the present invention is a motor having a feedback system including a plurality of controllers to which feedback signals related to the operation of a motor for a control shaft configured to apply a predetermined unbalanced load are input. A control device, in which current controllers included in the plurality of controllers include a current controller for controlling a d-axis current and a q-axis current related to the current supplied to the motor; a processing unit that detects the magnetic pole position of the motor in a state in which the predetermined unbalanced load and the driving force that the mover receives from the stator of the motor are balanced by applying a control current to the motor. . Then, the processing unit increases the control current in the same phase as the control current forming the driving force by the current control unit while maintaining a balanced state between the predetermined unbalanced load and the driving force. A first process and a second process of calculating the magnetic pole position of the motor based on the amount of displacement of the mover by the first process and the control current increased by the first process are executed. configured to

The motor control device has a feedback system including a plurality of controllers, and servo control of the motor is realized by these controllers. The feedback system is not limited to any particular form. The plurality of controllers includes a current controller that generates a voltage command to a power converter such as an inverter that supplies drive current to the motor. The current controller controls the d-axis current and the q-axis current in order to realize vector control of the motor by this current controller. Furthermore, the feedback system may include, in addition to the current controller, a controller higher than the current controller for servo-controlling at least the operation of the motor. A position controller and a speed controller can be exemplified as controllers on the upper side.

Here, the processing unit applies a control current to the motor and balances a predetermined unbalanced load with the driving force received by the mover from the stator of the motor, and performs the first processing and the second processing in this order. to detect the magnetic pole position of the motor. This detection of the magnetic pole position may be performed, for example, when the power supply to the motor control device is restarted, or may be performed at any timing required by the user. In the first process, in a state of balance between a predetermined unbalanced load and driving force, the control current is increased in phase with the phase of the control current forming the driving force for the balance. At this time, since the magnetic pole position of the motor is not detected after the power is turned on, the application of the control current and the increase processing of the control current in the first processing are performed on the assumption that the magnetic pole position is temporarily held by the motor control device. should be performed.

Here, the balance state between the driving force and the unbalanced load due to the control current increased by the first process is maintained by the feedback system, so that the mover of the motor is displaced. It was found that this displacement amount of the mover is related to the current control in the current control section by the feedback system, and has a predetermined correlation with the control current increased by the first process. Since the d-axis and the q-axis form orthogonal coordinates, there is a correlation represented by, for example, a predetermined trigonometric function between the displacement amount and the increased control current. Therefore, in the second process, the magnetic pole position of the motor is calculated based on the amount of displacement of the mover through the first process and the control current increased in the first process. For example, based on the correlation, the processing unit may, in the second processing, calculate the first A phase shift of the control current forming the driving force before one process may be calculated, and the magnetic pole position of the motor may be calculated from the phase shift. Note that the correlation between the two may be a correlation other than the relationship represented by a trigonometric function, for example, a correlation defining a one-to-one numerical relationship between the two.

With such a configuration, the motor control device can detect the magnetic pole position of the motor. At this time, since the predetermined unbalanced load and the driving force are balanced by the controller of the feedback system, the moving amount of the mover of the motor can be suppressed as much as possible. In addition, since there is no need to repeat a predetermined process many times as in the conventional technique of applying a current command, it is possible to shorten the time required to detect the magnetic pole position.

Here, in the motor control device described above, the processing unit may increase the control current with a predetermined time constant in the first processing. If the control current is sharply increased in the first process, the displacement of the mover by the current control unit via the feedback system becomes oscillating, which may adversely affect the accuracy of detecting the magnetic pole position of the motor. Therefore, it is preferable to perform the process of increasing the control current with a predetermined time constant.

Here, in the motor control device described above, the processing unit, before the first process, controls the moving element obtained by the feedback system when the braking state of the moving element of the motor is canceled. A control current may be applied to the motor based on the speed information to form a state in which the predetermined unbalanced load and the driving force received by the mover from the stator of the motor are balanced. The magnetic pole position of the motor has not yet been detected when the braking state of the mover of the motor is released. Therefore, the motor control device is designed so that the speed of the mover becomes zero even when a predetermined unbalanced load is applied, in other words, the mover is stopped by the driving force acting between the stator and the mover. A control current is applied to the motor in accordance with the tentative magnetic pole position of , forming a balanced state for the first process and the second process.

The control current increasing process in the first process is performed with the control current for forming this balanced state as a starting point. That is, the current value is increased while maintaining the phase of the control current forming the balanced state (the phase according to the temporary magnetic pole position of the motor control device). Moreover, the application of the control current for forming the balanced state for the first process and the second process may adopt a form other than the above. For example, the position information and acceleration information of the mover obtained by the feedback system may be used to apply the control current, or other forms of application of the control current may be employed.

Further, the technical concept relating to the motor control device described above can be applied to both a permanent magnet synchronous rotary motor and a permanent magnet synchronous linear motor.

When detecting the magnetic pole position of a motor for a control shaft configured to apply an unbalanced load, unnecessary movement of the mover of the motor can be suppressed and the time required for detecting the magnetic pole position can be shortened as much as possible. can.

1 is a diagram showing a schematic configuration of a servo system including a servo driver according to an embodiment of the invention; FIG. FIG. 3 is a diagram showing a control structure of a feedback system that a servo driver has; FIG. 4 is a diagram showing the control structure of a current controller that the servo driver has; FIG. 10 is an illustration of a method for establishing armature equilibrium after release of the brake in the vertical axis; FIG. 4 is a first diagram for explaining a method of estimating a magnetic pole position of a motor by the servo driver of the present invention; FIG. 4 is a second diagram for explaining a method of estimating the magnetic pole position of the motor by the servo driver of the present invention; 4 is a flow chart showing a flow of estimation processing of the magnetic pole position of the motor by the servo driver of the present invention; FIG. 10 is a diagram showing an increase transition of a control current in a process of estimating a magnetic pole position of a motor;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. This disclosure presents an industrial system as one exemplary form of servo system. However, the application of the servo system according to the present invention is not particularly limited. It should be noted that the phases indicated in the specification of the present application are based on the electrical angle unless otherwise specified.

<Example 1>
FIG. 1 is a schematic configuration diagram of a control system including a servo driver 4 according to an embodiment of the invention. The control system includes a network 1 , a motor 2 , a load device 3 , a servo driver 4 and a PLC (Programmable Logic Controller) 5 . In this control system, the PLC 5 generates an operation command signal, which is delivered to the servo driver 4 via the network 1 . The servo driver 4 servo-controls the motor 2 configured to drive the load device 3 to be controlled according to the operation command signal. Here, as the load device 3 , various mechanical devices (for example, an arm of an industrial robot and a transfer device) can be exemplified, and the motor 2 is attached to the load device 3 as an actuator for driving the load device 3 . For example, motor 2 is an AC servomotor.

An encoder 21 is attached to the motor 2 , and a parameter signal regarding the operation of the motor 2 is fed back to the controller 40 of the servo driver 4 by the encoder 21 . The encoder 21 is an incremental encoder. A parameter signal (hereinafter referred to as a feedback signal) that is feedback-transmitted to the control unit 40 includes, for example, position information about the position of the mover of the motor 2, information on the speed of the mover, and the like. Also, the motor 2 is an actuator for driving the vertical axis (Z-axis) of the load device 3 and has a braking device 22 for braking. The brake device 22 may be configured separately from the motor 2 so as to apply a braking force to the vertical axis of the load device 3 . Braking and releasing of the brake 22 are executed by a control signal from the servo driver 4 via a brake signal line (not shown).

Also, the control unit 40 of the servo driver 4 performs servo control of the motor 2 based on the operation command signal from the PLC 5 and the feedback signal from the encoder 21 and supplies drive current to the motor 2 via the inverter 6 . The AC power sent from the AC power supply 7 to the inverter 6 is used as the supplied current. In this embodiment, the inverter 6 is of a type that receives three-phase alternating current, but may be of a type that receives single-phase alternating current. The controller 40 of the servo driver 4 has a feedback system including a position controller 41 , a speed controller 42 and a current controller 43 .

Here, based on FIG. 2, the control structure of the feedback system of the control section 40 of the servo driver 4 will be described. A feedback system of the control unit 40 includes a position controller 41 , a speed controller 42 and a current controller 43 . The position controller 41 performs proportional control (P control), for example. Specifically, the speed command V_ref is calculated by multiplying the position deviation, which is the deviation between the position command P_ref from the PLC 5 and the current position value P_act of the motor 2, by a predetermined position proportional gain. The current position value P_act is a parameter indicating the current position of the motor 2 obtained by inputting the output of the encoder 21 to the position detector 45 .

The speed controller 42 performs proportional integral control (PI control), for example. Specifically, the integral amount of the speed deviation, which is the deviation between the speed command V_ref calculated by the position controller 41 and the current speed value V_act of the motor 2, is multiplied by a predetermined speed integral gain, and the calculation result and the speed deviation A torque command τ_ref is calculated by multiplying the sum of , by a predetermined speed proportional gain. Also, the speed controller 42 may perform P control instead of PI control. The current speed value V_act is a parameter representing the current speed of the motor 2 obtained by inputting the output of the position detector 45 to the speed detector 46 .

The current controller 43 adjusts the current based on the torque command τ_ref calculated by the speed controller 42 , the current position value P_act and the current speed value V_act of the motor 2 , and the drive current supplied to the motor 2 from the inverter 6 . A command is generated, and a voltage command corresponding to each phase of the three-phase AC motor is output to the inverter 6 based on the current command. Upon receiving the voltage command, the inverter 6 applies a drive voltage to each phase (U phase, V phase, W phase) of the motor 2 to drive and control the motor 2 . The driving current supplied to the motor 2 is detected by a current detector 44. FIG. In FIG. 2, the configuration corresponding to each phase of the motor 2 is illustrated in a simplified manner. The current value of each phase is returned to the current controller 43 . The current controller 43 may include a filter (primary low-pass filter) and one or more notch filters related to the torque command.

Next, the control structure formed in the current controller 43 will be described with reference to FIG. Vector control is performed in the current controller 43 . Therefore, the torque command τ_ref input to the current controller 43 is first input to the current command calculator 51 . Current speed value V_act of motor 2 is further input to current command calculator 51 to generate d-axis current command Id_ref and q-axis current command Iq_ref. Then, the deviation between the d-axis current command Id_ref and the d-axis current Id currently flowing through the motor 2 is input to the d-axis current controller 52, and the q-axis current command Iq_ref and the q-axis current flowing through the motor 2 A deviation from the current Iq is input to the q-axis current controller 53 . The d-axis current Id and the q-axis current Iq currently flowing through the motor 2 are represented by the current coordinates of the currents Iu, Iv, and Iw flowing through the U-phase, V-phase, and W-phase of the motor 2 detected by the current detector 44. It is input to the converter 56, where it is calculated by performing dq conversion processing.

The d-axis current controller 52 calculates a voltage command Vd for the d-axis from the deviation of the input d-axis current in consideration of the physical parameters of the motor 2. Similarly, the q-axis current controller 53 A voltage command Vq for the q-axis is calculated from the input deviation of the q-axis current in consideration of the physical parameters of the motor 2 . The calculated voltage commands Vd and Vq are input to the voltage coordinate converter 54 . The voltage coordinate converter 54 converts the input d-axis voltage command and q-axis voltage command from the dq-axis to a three-phase voltage command Vu , Vv, Vw. These voltage commands are handed over to the PWM calculator 55 where they are formed as commands to the inverter 6 and sent to the inverter 6 .

In the servo driver 4 configured as described above, when the power is turned off once and then turned on again, the encoder 21 of the motor 2 is an incremental encoder. Also, its magnetic pole position must be detected. If the magnetic pole position is not accurately detected, suitable servo control of the motor 2 becomes difficult, and in general, it is desired that the motor 2 operate quickly and safely after the power is turned on. Therefore, the principle of the magnetic pole position detection process that can shorten the time required for the magnetic pole position detection process of the motor 2 as much as possible and suppress unnecessary movement of the output shaft of the motor 2 during the detection process is as follows. It is explained below.

Here, as shown in FIG. 1, the motor 2 is the actuator that drives the vertical axis of the load device 3 . Therefore, an unbalanced load is applied to the output shaft of the motor 2 due to the gravity of the driven object on the vertical axis. In this embodiment, it is assumed that the unbalanced load is applied in the vertical direction. Therefore, for example, when the power supply to the servo driver 4 is restarted after being stopped, that is, when the power of the servo driver 4 is turned on, the magnetic pole position of the motor 2 is not accurately detected. That is, the d-axis and q-axis temporarily held by the servo driver 4 are
The axis is deviated from the theoretically set axis based on the mover (rotor) of the motor 2 . Therefore, for suitable servo control of the motor 2, it is necessary to detect the magnetic pole position. Note that the magnetic pole position detection processing may be performed at any timing desired by the user after the power is turned on, instead of when the power is turned on.

Here, while the servo driver 4 is powered off and the motor 2 is stopped, the braking device 22 applies a predetermined braking force to the output shaft of the motor 2 to brake the output shaft. When the power of the servo driver 4 is turned on to servo-control the motor 2, the braking state by the braking device 22 is released. (an object driven by the motor 2) falls vertically, and the mover of the motor 2 is displaced accordingly.

In the magnetic pole position detection process of this embodiment, after the braking by the brake device 22 is released, the unbalanced load applied to the mover of the motor 2 and the driving force (magnetic force) received from the stator side of the motor 2 are balanced. is done in Therefore, a method for forming the balanced state will be described with reference to FIG. FIG. 4 schematically shows the position and posture of the mover with respect to the stator when the brake device 22 is released and the mover of the motor 2 starts to displace due to the unbalanced load, superimposed over time. It is what I did. In FIG. 4, the stator is provided with permanent magnets, the magnetic poles of which are alternately arranged as N poles and S poles. On the other hand, the magnetic poles formed in the mover are formed in a controllable manner by coils such as windings. In FIG. 4, the mover and stator of the motor 2 are described according to the form of a permanent magnet synchronous linear motor in order to facilitate understanding of the disclosure of the present application. There is no intention to exclude synchronous rotary motors. Those skilled in the art will understand that even if the motor 2 is a permanent magnet synchronous rotary motor, it can be expressed in principle in the form shown in FIG.

Here, the left side (a) of FIG. 4 shows the formation of the balanced state according to the prior art configuration. In the prior art, the phase of the control current flowing through the windings of the mover is kept constant after the braking by the brake device 22 is released. In this case, the mover is displaced with respect to the stator according to the unbalanced load while the direction of the magnetic pole remains fixed. At this time, a state in which an attractive force f1 is generated by the magnetic poles of the mover and the magnetic poles of the stator is shown. Assuming that the vertical component force of this attractive force f1 is f11 and the horizontal component force is f12, the component force f11 is generated to resist the unbalanced load f2. Therefore, if the force component f11 and the offset load f2 are balanced, the mover can be fixed to the stator. However, in the prior art, since the orientation of the magnetic poles of the mover is fixed, there is an opportunity to quickly create a state in which the movement of the mover is stopped by the attractive force or repulsive force generated between the magnetic poles generated on the stator side. Limited. Therefore, when the speed of the mover increases due to the fall, the mover cannot necessarily be stopped. For example, in the state shown in FIG. 4(a), when the force component f11 is smaller than f2, the mover does not stop, but accelerates further and falls due to the biased load. Also, even if the component force f11 and f2 are momentarily balanced, when the falling speed increases, it is difficult for the mover to stop immediately due to the effect of the speed, and as a result, the position where the mover is drawn to the next stator side If it continues to fall, the speed of the mover will increase further, making it difficult to stop the mover.

On the other hand, in the disclosure of the present application, as shown in the right side (b) of FIG. The mover is displaced with respect to the stator according to the unbalanced load while suitably servo-controlling the orientation. Specifically, in the feedback system shown in FIGS. 2 and 3, a signal of speed 0 is input as the speed command V_ref, and current control by the current controller 43 is performed based on the current speed value V_act and the speed command V_ref to be fed back. is performed and a control current is applied to the windings of the mover. As a result, an attractive force or a repulsive force for stopping the mover is quickly generated between the mover and the stator. FIG. 4B shows a state in which a repulsive force f3 is generated by the magnetic poles of the mover and the magnetic poles of the stator. Assuming that the vertical component force of this repulsive force f3 is f31 and the horizontal component force is f32, the component force f31 is generated to resist the unbalanced load f4. Then, when the component force f31 and the offset load f4 are balanced, the mover can be fixed to the stator. In the form of FIG. 4(b), suitable attractive force or repulsive force can be generated quickly, so that the speed of the mover can be effectively reduced before it increases significantly as shown in FIG. 4(a). , and the unbalanced load applied to the mover of the motor 2 and the driving force received from the stator side of the motor 2 can be balanced.

Note that the current speed value V_act is used for the control of the orientation of the magnetic poles of the mover based on the feedback signal of the feedback system of the control unit 40. The current speed value V_act is the speed of the mover and its It can be understood that it contains information about the direction of movement. In addition to the information about the speed of the mover, information about the position of the mover (for example, the current position value P_act) and information about the acceleration of the mover (for example, a value calculated by further differentiating the current speed value V_act) may also be used to control the orientation of the magnetic poles of the mover. When using the information on the position of the mover, a signal for fixing the position is input as the position command P_ref, and when using the information on the acceleration of the mover, the signal of torque 0 is input as the torque command τ_ref. Just enter it.

As shown in FIG. 4B, by balancing the unbalanced load applied to the mover of the motor 2 and the driving force received from the stator side of the motor 2, the detection processing of the magnetic pole position of the motor 2 is stably performed. be able to. Next, based on FIG.5 and FIG.6, the detection process of the magnetic pole position of the motor 2 is demonstrated. In FIG. 5, the orthogonal coordinates set on the stator side of the motor 2 are represented by the α-axis and the β-axis. Let Iref be the current command for the applied current when the control current is applied by the feedback system described above and the balanced state is established. At this time, the servo driver 4 does not know the exact positions of the d-axis and the q-axis shown in FIG. 5, and outputs the current command Iref based on the temporarily held magnetic pole information.

In FIG. 5, the current corresponding to the current command Iref generated by the current command calculator 51 is represented by vector V1. The direction of the vector V1 is defined as the α'-axis, and the direction orthogonal thereto is defined as the β'-axis. Let θbar be the angle formed by the α′-axis and the d-axis. Here, assuming that the d-axis component vector of the vector V1 is V2 and the q-axis component vector is V3, the q-axis current represented by the vector V3 is the current component that generates the driving force for balancing the unbalanced load. becomes. Looking at the vector correlation shown in FIG. 5, it can be understood that the d-axis and q-axis positions can be detected based on the phase of the current command Iref by calculating the angle θbar between the vector V1 and the vector V2. .

Next, in FIG. 6, a vector V1 (corresponding to the current command Iref), a vector V2 (corresponding to the d-axis current command), a vector V3 (q corresponding to the axis current command). Here, the command value is increased while the phase of the current command Iref is fixed while the control by the feedback system for forming the balanced state is maintained. In FIG. 6, the current corresponding to the increased current command Iref' is represented by vector V10. The process of increasing the current command while maintaining the balance by the feedback system of the control unit 40 is referred to as "first process".

Here, even if the current command is increased from Iref to Iref' by the first process, the balanced state is maintained by the feedback system, so the mover of the motor 2 is displaced (rotated). This rotation will be explained. When the current command is increased to Iref', the q-axis current command Iq' is formed to pass the q-axis current corresponding to the unbalanced load, and the d-axis current command Id' is univocally changed to pass the d-axis current. It is formed. Currents corresponding to the d-axis current command Id' and the q-axis current command Iq' are represented by vectors V20 and V30, respectively. The vector V20 is shifted by Δθ from the vector V2, and the vector V30 is similarly shifted by Δθ from the vector V3. Therefore, the mover of the motor 2 is displaced by the amount corresponding to this vector deviation Δθ (electrical angle).

・・・（式１）
そして、式１に基づいて、θｂａｒを導出する式２は下記の通りとなる。

・・・（式２）
したがって、電流指令Ｉｒｅｆ、Ｉｒｅｆ’、変位量Δθに基づいて、式２からθｂａｒが算出できる。そして、電流指令Ｉｒｅｆの位相とθｂａｒに基づいて、モータ２の磁極位置を算出することができる。 Therefore, the magnetic pole position of the motor 2 is calculated based on the amount of displacement of the mover by the first process (corresponding to Δθ described above) and the control current increased by the first process (current due to vector V10 described above). A second process of calculating is performed. As described above, the magnetic pole position of the motor 2 is θbar
should be calculated. Specifically, since the magnitudes of vector V3 and vector V30 are equal from the viewpoint of balance with the unbalanced load, Equation 1 below is established.

... (Formula 1)
Based on Equation 1, Equation 2 for deriving θbar is as follows.

... (Formula 2)
Therefore, θbar can be calculated from Equation 2 based on the current commands Iref and Iref' and the displacement amount Δθ. Then, the magnetic pole position of the motor 2 can be calculated based on the phase of the current command Iref and θbar.

Next, the flow of detection processing of the magnetic pole position of the motor 2 executed when the power of the servo driver 4 is turned on will be described with reference to FIG. The detection process shown in FIG. 7 is realized by executing a predetermined control program in the control unit 40 of the servo driver 4 when the power of the servo driver 4 is turned on. First, in S101, a release command is sent to the brake device 22 of the motor 2, and the braking state by the brake device 22 is released. As a result, an unbalanced load is applied to the mover of the motor 2, and displacement due to the unbalanced load begins to occur. Therefore, in the following S102, as described with reference to FIG. 4B, in the feedback system of the control unit 40, a signal of speed 0 is input as the speed command V_ref, and the current speed value V_act to be fed back and the speed command Current control by the current controller 43 is performed based on V_ref. As a result, a control current is applied to the motor 2, and a driving force for stopping the mover is quickly generated between the mover and the stator.

However, if for some reason the speed of the mover is not sufficiently reduced even by the driving force, the mover may fall to the end of its movable range and damage the load device 3 . Therefore, in S103, it is determined whether or not the speed of the mover exceeds a predetermined speed in the current control performed in S102. The predetermined speed is a drop speed at which it is difficult to stop the mover by the driving force, and may be appropriately set by prior experiments or the like. Then, if the determination in S103 is affirmative, the process proceeds to S107, the braking device 22 is operated to stop the mover by the braking force, and this detection process ends. On the other hand, if a negative determination is made in S103, the process proceeds to S104, where it is determined whether or not the unbalanced load applied to the mover and the driving force are balanced and the mover has stopped. The balance can be determined using the current speed value V_act in the feedback system. If an affirmative determination is made in S104, the process proceeds to S105, and if a negative determination is made, the processes after S102 are repeated.

Then, in S105, the above-described first process is performed, and then in S106, the above-described second process is performed. As a result of these processes, the magnetic pole position of the motor 2 driving the vertical shaft to which the load device 3 is subjected to an unbalanced load is accurately detected. Further, in the magnetic pole position detection processing by the first processing and the second processing, the mover of the motor 2 is displaced only by the amount corresponding to Δθ, so the time required for the magnetic pole position detection processing can be shortened. In the above-described first process, the current command Iref is increased to Iref'. can have an unfavorable effect on Therefore, as shown in FIG. 8, for the increase in the current command (increase from Iref to Iref') in the first process, the voltage coordinate converter 54 to output the voltage command.

The disclosure of the present application can be applied to both a permanent magnet synchronous rotary motor and a permanent magnet synchronous linear motor.

In addition, in order to perform the magnetic pole position detection processing by the first processing and the second processing, it is necessary to balance the unbalanced load applied to the mover and the driving force between the mover and the stator. A method other than the above-described method described with reference to FIG. For example, if the balanced state can be formed by the conventional technique shown in FIG. 4(a), then the magnetic pole position detection processing can be performed by the first processing and the second processing.

<Appendix 1>
A motor control device (4) having a feedback system including a plurality of controllers to which feedback signals related to the operation of a control shaft motor (2) configured to apply a predetermined unbalanced load are input,
a current control unit for controlling a d-axis current and a q-axis current related to the current supplied to the motor (2) in the current controller (43) included in the plurality of controllers;
By applying a control current to the motor (2) by the current control unit, the motor (2) can be operated in a state in which the predetermined unbalanced load and the driving force received by the mover from the stator of the motor are balanced. a processing unit that detects the magnetic pole position of
with
The processing unit is
a first process (S105) in which the current control unit increases the control current in the same phase as the control current forming the driving force while maintaining the balanced state between the predetermined unbalanced load and the driving force; and a second process (S106) of calculating the magnetic pole position of the motor based on the amount of displacement of the mover by the first process and the control current increased by the first process. configured to
motor controller.

2 motor 3 load device 4 servo driver 5 PLC
6 inverter 21 encoder 22 brake device 41 position controller 42 speed controller 43 current controller

Claims (5)

A motor control device having a feedback system including a plurality of controllers to which feedback signals relating to the operation of a motor for a control shaft configured to apply a predetermined unbalanced load are input,
a current controller that controls a d-axis current and a q-axis current related to the current supplied to the motor, in the current controllers included in the plurality of controllers;
By applying a control current to the motor by the current control unit, the magnetic pole position of the motor is detected in a state in which the predetermined unbalanced load and the driving force received by the mover from the stator of the motor are balanced. a processing unit;
with
The processing unit is
a first process of increasing the control current in the same phase as the control current forming the driving force by the current control unit while maintaining a balanced state between the predetermined unbalanced load and the driving force; A second process of calculating the magnetic pole position of the motor based on the displacement amount of the mover displaced by the first process and the control current increased by the first process,
motor controller. In the second process, the processing unit adjusts the driving force before the first process with respect to a predetermined current axis forming the magnetic pole position of the motor based on the displacement amount and the increased control current. calculating a phase shift of the control current to be formed, and calculating a magnetic pole position of the motor based on the phase shift;
The motor control device according to claim 1. The processing unit increases the control current with a predetermined time constant in the first processing,
The motor control device according to claim 1 or 2. The processing unit is
applying a control current to the motor based on speed information of the mover obtained by the feedback system when the brake state of the mover of the motor is released before the first processing, forming a state in which the predetermined unbalanced load and the driving force received by the mover from the stator of the motor are balanced;
The motor control device according to any one of claims 1 to 3. The motor is a permanent magnet synchronous rotary motor or a permanent magnet synchronous linear motor,
The motor control device according to any one of claims 1 to 4.

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