JPH0819279A - Speed controller of motor - Google Patents

Abstract

PURPOSE:To correct an acceleration/deceleration current command value easily and besides highly accurately and prevent the drop of the response speed during acceleration/deceleration operation by a current command limit value by limiting the speed command change rate limiting value for controlling the rate of change of the speed command to a motor by the maximum tolerable change rate value of the speed command. CONSTITUTION:When a speed command wr* is inputted, a speed command change rate limiter 5 outputs a speed command wr**. An acceleration/ deceleration current command Iad made by the speed command wr** is automatically adjusted so that the current command I* may be the current limiting value ILimit of a current command limiter 10a, and the speed wr of a motor is outputted to finish the acceleration/deceleration. Therefore, the speed wr follows the speed command wr**. It turns out that the current equivalent to the current command wr** is supplied to the motor 3 without being limited by the current command I**, and the deterioration of the response speed can be suppressed by using out the maximum capacity of the motor 3 within the current command limiting value iLimit.

Description

Detailed Description of the Invention [0001] BACKGROUND OF THE INVENTION The present invention relates to a speed control device for an electric motor.
Position, especially the acceleration / deceleration operation based on the current command limit value
The present invention relates to a speed control device for an electric motor. [0002] 2. Description of the Related Art The configuration of a conventional speed control device for an electric motor
4 shows. The electric motor 1 has a machine 3 which is a load and a connecting shaft 4
Connected and supplied to the motor 3 by the current control calculator 11.
Current I_aControl. Here, the current control calculator 11
The power converter includes a power converter.
Power is supplied through the converter. The speed control system is
Output device 2, speed command change rate limiter 5, load torque current command
Calculator 7, acceleration / deceleration current command calculator 8, current command limiter 1
0 and adders / subtractors 6 and 9. Now, speed command
ω_rWhen * is input to the speed command change rate limiter 5, the speed command
Change rate limit value Δω_rSpeed command change rate with *
From the limiter 5, speed command ω_r* Velocity with limited rate of change
Command ω_r** is output. Speed command with limited rate of change
ω_r** and motor speed ω which is the output of speed detector 2_rBias with
The difference is obtained by the subtractor 6, and this speed deviation is calculated by the load torque
Flow command calculator 7 and load torque current command value I_L*
Output. On the other hand, the speed command value ω_rAcceleration / deceleration current command
Input to the calculator 8 and set the acceleration / deceleration current command value I_ad(= K ・ dω_r*
* / Dt: K indicates a constant. ) Is output. Load torque
Current command value I_L* And acceleration / deceleration current command value I_adIn the adder 9
Then, the polarities shown in the figure are added. The output of the adder 9 is a current finger.
It becomes the regulation value I * and the current limit value I_LimitCurrent finger with
It is input to the command limiter 10. Power from the current command limiter 10
The flow command value I ** is output. The current control calculator 11 is
Current I of the motor 3_aControl
It Further, in this type of control configuration, JP-A-5-28
Japanese Patent No. 4774 discloses an inertial value of a machine including an electric motor.
Inertia estimator and acceleration / deceleration calculator that perform constant calculation and output
Provided, the rate of change of the speed command value is determined by the estimated inertia value
Level of the input speed command value while limiting within the limit value
Output a new speed command value that matches
However, a technique for controlling the speed of an electric motor is disclosed. [0003] [Problems to be Solved by the Invention]
In conventional motor speed controllers, acceleration / deceleration current commands
The response of the load torque current command calculator 7 is lower than that of the calculator 8.
When a control system is built, the current command will change when the speed command changes.
Limit value I_LimitThe speed response is
Will be deteriorated. This is not the case with conventional speed control configurations.
No consideration was given to the deterioration of the speed response of
Was. Here, using the time chart shown in FIG.
The deterioration of the response will be explained. For example, as shown in Figure 5 (a)
Time t₁At, the speed command ω * is input stepwise.
Then, the speed command change rate limiter 5 is set as shown in FIG.
Speed command ω with limited rate of change of speed command_rOutputs **
It The acceleration / deceleration current command calculator 8 operates at time t in FIG.₁
~ T₂As shown in,_rAdd according to the rate of change of **
Deceleration current command value I_adIs output. Also, load torque current
The command calculator 7 determines the load of the electric motor and the speed command ω._r**When
Speed of electric motor 3_r5 (e) according to the deviation of
Such load torque current command value I_LOutput *. Adder 9
At the acceleration / deceleration current command value I_adAnd load torque current command
Value I_L* Is added to the current command value as shown in Fig. 5 (f).
I *. Current limit value I_LimitCurrent command system with added
The current command I * is input to the limiter 10, and as shown in FIG.
As shown, the current limit value I_LimitCurrent command I * limited to
* Is output. The current control calculator 11 determines the current limit value I
_LimitInput current command I ** limited to
Control the flow Ia. In FIG. 5, the speed command ω_r**change of
Acceleration / deceleration current command value I of value C output according to the rate_adAnd negative
Load torque current command value I_L* Is added and shown in Fig. 5 (f)
Thus, the current command value I * is obtained. Speed of electric motor 3_rIs a book
Nowadays, a current corresponding to this current command I * is needed for acceleration / deceleration.
However, the current command limiter 10 causes the current command I *
Is limited to the current command I ** shown in FIG.
The electric current corresponding to the flow command I * can be supplied to the electric motor 3.
This is not possible, and time t in FIG.₁~ T₂As shown in
Does not follow the degree command ωr **. In other words, the speed command ωr ** is
Compared to changing from 0 to A as shown in 5 (b),
Speed of electric motor 3_rIs 0 as shown in FIG.
Changes to B (<A) and does not follow the speed command ωr **
Yes. Also, at time t₂After that, the speed command value ω_r** is one
When the constant value is reached, the acceleration / deceleration current command calculator 8 changes the motor speed.
ω_rAcceleration / deceleration because the output is stopped before the acceleration / deceleration ends.
Current value I_adIs zero and the current command value I * is the load torque
Flow command value I_LIs equal to *. This is the acceleration / deceleration current command
The response of the load torque current command calculator 7 is slower than that of the calculator 8.
The control function can also output the acceleration / deceleration current command component of the motor.
Is shown. As a result, the current command I ** is the current limit value.
I_LimitThe motor speed ω_rIn Fig. 5 (c)
As shown in_rDeviation H from ** occurs
It This is the current command limit value I_LimitAcceleration / deceleration operation within
When carrying out, maximize the performance of the electric motor.
No, it means that the speed response is deteriorated. Also on
According to the technology of the publication, it matches the level of the input speed command value.
To obtain a new speed command value
Limit the rate of change to within the limit determined by the estimated inertia value
However, the speed command value based only on the estimated inertia value
There is a limit to the rate of change of
Not of. In view of the above-mentioned circumstances, the purpose of the present invention is to provide electric power.
When performing acceleration / deceleration operation with the flow command limit value
To correct the acceleration / deceleration current command value easily and with high accuracy.
To maximize the performance of the electric motor within the command limit value
An object of the present invention is to provide a suitable motor speed control device. [0004] [Means for Solving the Problems] The above object is to provide a load torque.
Current command value, current command limit value, motor and machine
Speed command using the sex moment and the torque constant of the motor
The maximum permissible change rate value of the
Speed command that limits the rate of change
Achieved by limiting by the maximum permissible rate of change value of
Is done. [0005] According to the present invention, the acceleration / deceleration current command value changes the speed command.
Pay attention to the place where is output by the load torque current command
Value, current command limit value, motor and machine inertia moment
The maximum acceleration / deceleration of the electric motor can be obtained from the torque constant of the electric motor.
The maximum allowable change rate value of the speed command
Limit the conversion rate limit value by the maximum allowable change rate value of the speed command.
Therefore, the acceleration / deceleration current command value can be corrected easily and with high accuracy.
It is possible to perform acceleration / deceleration operation according to the current command limit value.
If the current command limit value is exceeded, the performance of the motor can be maximized.
It is possible to prevent start-up and deterioration of speed response. [0006] Embodiments of the present invention will be described below with reference to the drawings.
It FIG. 1 is a speed control of an electric motor showing an embodiment of the present invention.
It is a block diagram of an apparatus. In FIG. 1, the same configuration as in FIG.
The same symbols are used for the elements, and the description is omitted. Real
An example is shown in FIG.
2. A speed command change rate value limiter 13 is added. In Figure 2,
A specific configuration of the speed command maximum allowable change rate value calculator 12
Show. The maximum allowable change rate value calculator 12 for the speed command is
Torque current command value I_L*, Current command limit value I_Limit,electric
Torque constant ζφ of the machine, the inertia of the motor 1 and the machine 3 (load)
Take in the sex moment J. Current command limit value I_LimitWhen
Load torque current command value I_LCalculate the deviation of * with the subtractor 12a
It The torque τ required for acceleration / deceleration of the electric motor 1 and the machine 3 is
The output of the subtractor 12a and the torque constant ζφ of the electric motor are multiplied by each other.
It is obtained by multiplying by 12b. Maximum speed command allowance
Change rate value △ ω_r*_(MAX)Is the output of the multiplier 12b
1 and the moment of inertia J of machine 3 use divider 12c
And divide it to find. In Figure 1, speed
The maximum allowable change rate value of the command
Large allowable change rate value Δω_r*_(MAX)The speed command change rate value limiter
13 and outputs the speed command maximum allowable change rate value Δω_r*_(MAX)
Is added to the speed command change rate value limiter 13,
Change rate limit value Δω_rEnter * to specify the maximum speed change rate
Value △ ω_r*_(MAX)Speed command change rate limit limited by
Value △ ω_rOutput **. This speed command change rate limit value Δω_r
** is input to the speed command change rate limiter 5, and the speed command ω
_r* Adjust the rate of change. Next, from the acceleration / deceleration current command calculator 8, the load
Build a control system with low response of the torque current command calculator 7,
The operation of the speed control device when using the present invention is shown in FIG.
This will be explained using a time chart. Speed command ω_r*But,
As shown in FIG. 6A, time t₁In step form
When applied, the speed command change rate limiter 5
Maximum permissible speed command output from the large permissible change rate value calculator 12
Change rate value △ ω_r*_(MAX)And speed command change rate value limiter 1
Based on the output of 3, the speed command ω as shown in FIG._r**
Is output. That is, the speed command ω_r** is time t₁~ T₃while
At time t₃And reach A. As a result, FIG.
As shown in (d), time t₁~ T₃During the speed command ω_r**
Acceleration / deceleration current command I created by_adHas the value C '
So that the current command I * is the current command limiter 1
0 current limit value I_LimitIs automatically adjusted to
It Also, the acceleration / deceleration current command I_adIs the speed of the motor ω_rBut
It is output until the end of acceleration / deceleration. As a result, the speed of the motor
Degree ω_rIs the speed command ω as shown in FIG._rFollow **
I do. In other words, when the speed command ωr ** changes, the motor
Speed of 3_rFollows this and is shown in FIG.
Change from 0 to A. This is the speed command ω_r**But
During the changing acceleration / deceleration operation, the current command I * is the current limit value.
I_LimitAcceleration / deceleration current command I_adAutomatically
Adjusted, acceleration / deceleration current command value I_adAnd load torque current command
Value I_LThe current command I * output by addition with * is the current
Command limit value I_LimitIt is controlled by. This result
As a result, the current command I * is shown in FIG.
As shown in (g), it is not limited to the current command I **.
The electric current corresponding to the electric current command I * is supplied to the electric motor 3.
Therefore, the speed ω of the electric motor 3_rIs shown in FIG.
Time t₁~ T₃Follows the speed command ωr ** as shown in
It As described above, the speed control device of the present embodiment uses the current command
Limit value I_LimitMaximize the capacity of the electric motor 3 within
However, the deterioration of the speed response is suppressed. FIG. 3 shows an electric motor according to another embodiment of the present invention.
The block diagram of the speed control apparatus of FIG. In FIG. 3, as in FIG.
The same symbols are used for the same components and explanations are omitted.
I do. 4, the speed command change rate limiter 14 and FIG.
The maximum allowable change rate value calculator 12 for the speed command described in
In addition, the speed command change rate limiter 14 limits the speed command change rate.
The speed command change rate limiter 14 is provided between the converter 5 and the subtractor 6.
The speed output by the maximum allowable change rate value calculator 12 of the speed command
Degree command maximum allowable change rate value Δω_r*_(MAX)Enter. Real
In the example, when the speed command ω * is input stepwise,
As shown in FIG. 5B, the speed command change rate limiter 5 is a speed command
Speed command ω with limited rate of change_rOutput **. This
Speed command ω shown in FIG._r** is the speed command change rate
The speed command maximum allowable change rate value Δω is input to the limiter 14.
_r*_(MAX)Speed command change rate limiter 1
4 to the speed command ω shown in FIG._rOutput **. Since
Below, the same operation as in the embodiment of FIG. 1 is performed. This allows
The same effect as the embodiment of FIG. 1 can be obtained. In the embodiment of the present invention, the load torque is
Current command value I_LIf the maximum value of * is known in advance, the current finger
Limit value I_Limit, Torque constant ζφ of motor, motor and
And the moment of inertia J of the machine (load) is fixed and the speed is fixed.
Command maximum allowable change rate value Δω_r* _(MAX)And asked for this
Speed command maximum allowable change rate value △ ω_r*_(MAX)Change speed command
Set the rate limiter 13 and the speed command change rate limiter 14
May be. [0010] As described above, according to the present invention.
Load torque current command value, current command limit value, motor and
The moment of inertia of the machine and the torque constant of the motor,
Maximum permissible rate of change value of speed command at which the motive can be accelerated / decelerated to the maximum
To limit the rate of change of speed command to the motor
Change the speed command change rate limit value to the maximum allowable change rate of this speed command.
Since it is limited by the value, the acceleration / deceleration current command value
The current command limit value can be corrected easily and accurately.
When performing acceleration / deceleration operation by
To maximize the performance of the, prevent the deterioration of speed response
can do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a speed control device for an electric motor showing an embodiment of the present invention. FIG. 2 is a specific block diagram of a speed command maximum allowable change rate value calculator. FIG. 4 is a configuration diagram of a speed control device for an electric motor showing another embodiment of the present invention. FIG. 4 is a configuration diagram of a speed control device for a conventional electric motor. FIG. 5 is a time chart for explaining the operation principle of the conventional control device. Time chart for explaining the operation principle of the present invention [Explanation of symbols] 1 Motor 2 Speed detector 3 Machine (load) 4 Connecting shafts 5 and 14 Speed command change rate limiter 6 Subtractor 7 Load torque current command calculator 8 Addition Deceleration current command calculator 9 Adder 10 Current command limiter 11 Current control calculator 12 Speed command maximum allowable change rate value calculator 13 Speed command change rate value limiter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiji Kunii             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Ceremony company Hitachi Ltd. Omika factory (72) Inventor Tadakatsu Kinase             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Ceremony company Hitachi Ltd. Omika factory (72) Inventor Jiro Nemoto             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Ceremony company Hitachi Ltd. Omika factory

Claims (1)

Claim: What is claimed is: 1. An electric motor for driving a load, a speed command change rate limiting means for limiting a change rate of a speed command for the electric motor by a speed command change rate limiting value, and the speed command change rate limiting means. In a speed control device for an electric motor, which comprises a speed control system having a current command limiting means for limiting a current command value obtained by adding a load torque current command value and an acceleration / deceleration current command value calculated based on the output of A current command limit value given to the current command limiting means, the load torque current command value, the moment of inertia of the electric motor and the load, and a maximum allowable change rate value of the speed command using the torque constant of the electric motor, A speed control device for an electric motor, wherein a speed command change rate limit value is limited by a maximum allowable change rate value of the speed command. 1. A motor for driving a load, speed command change rate limiting means for limiting a change rate of a speed command for the electric motor by a speed command change rate limiting value, an output of the speed command change rate limiting means, and the electric motor. The deviation from the detected speed value is input to the load torque current command calculation means for outputting the load torque current command value, and the acceleration / deceleration current necessary for accelerating / decelerating the electric motor from the output of the speed command change rate limiting means. Acceleration / deceleration current command calculation means for obtaining a command value, current command limiting means for limiting a current command value obtained by adding the load torque current command value and the acceleration / deceleration current command value, and the electric motor according to the output of the current command limiting means. In a speed control device for an electric motor having a current control means for controlling the current, the current command limit value given to the current command limit means and the load torque current command value Determining the maximum allowable change rate value of the speed command using the moment of inertia of the electric motor and the load and the torque constant of the electric motor, and limiting the speed command change rate limit value by the maximum allowable change rate value of the speed command. A speed control device for an electric motor. 2. An electric motor for driving a machine, a first speed instruction change rate limiting means for limiting a change rate of a speed instruction for the electric motor by a speed instruction change rate limiting value, and an output of the speed instruction change rate limiting means. And a speed torque change value of the electric motor, and a load torque current command calculating means for outputting a load torque current command value, and an output of the speed command change rate limiting means are necessary for accelerating and decelerating the electric motor. Acceleration / deceleration current command calculation means for obtaining an acceleration / deceleration current command value, current command limiting means for limiting a current command value obtained by adding the load torque current command value and the acceleration / deceleration current command value, and an output of the current command limiting means According to the above, in a speed control device for an electric motor having a current control means for controlling the electric current of the electric motor, a second speed command change rate limiting means is provided in series with the first speed command change rate limiting means. A step is provided, and the current command limit value given to the current command limiting means, the load torque current command value, the moment of inertia of the electric motor and machine, and the maximum allowable change rate value of the speed command using the torque constant of the electric motor. And the maximum allowable change rate value of the speed command is input to the second speed command change rate limiting means to limit the change rate of the speed command output from the first speed command change rate limiting means. And the speed control device of the electric motor. 4. The motor according to claim 1, wherein the maximum allowable change rate value of the speed command is obtained by multiplying a deviation value between the current command limit value and the load torque current command value by a torque constant of the motor. And a speed control device for an electric motor, wherein a torque required for accelerating and decelerating the machine is obtained, and the torque is divided by a moment of inertia of the electric motor and the machine.