JP2003102188A - Drive control unit of electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive control unit of motors, capable of improving reliability and maintenance performance of a mechanical system, in driving a plurality of motors at a predetermined speed and driving the mechanical system. SOLUTION: The drive control unit for variably controlling the speeds of two motors is provided with a first and second motors 102 and 202. The motors are connected to both shafts of a rotating body 6 via gears 104 and 204 respectively, and drive the rotating body 6, while sharing the load. A master control unit 100 drives the first motor 102 with a speed command ωr*, and the master control unit 100 and a slave control unit 200 are connected to each other via an optical transmission channel 300. Various kinds of control information is transmitted from the master control unit 100 to the slave control unit 200.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for an electric motor that drives a mechanical system while sharing a load with a plurality of electric motors. The present invention relates to the one in which the load sharing among them is performed evenly.

[0002]

2. Description of the Related Art In general, in order to operate a mechanical system at a predetermined speed with an electric motor, it is necessary to control the speed of the electric motor while immediately responding to fluctuations in the load applied to the mechanical system.

FIG. 2 is a block diagram showing the structure of a drive control device for controlling the speed of a motor by a fully closed loop. A speed command is given to the control device 1, and the electric motor 2 is driven by a drive command based on a difference signal from the speed detection signal detected by the encoder 3a. A rotating body (machine to be controlled) 6 is connected to the electric motor 2 via a gear 4 and a shaft 5, and the encoder 3a detects the speed of the rotating body 6 and outputs a speed detection value to the control device 1. I try to give feedback.

FIG. 3 is a block diagram showing an example of semi-closed loop control in which the speed of a mechanical system is controlled by one electric motor. When driving the electric motor 2 based on the speed command, the control device 1 detects the rotation speed of the electric motor 2 with the encoder 3b. As a result, the electric motor 2 and the gear 4,
The speed of a rotating body (machine to be controlled) 6 connected via a shaft 5 is controlled. However, in practice, various adjustments and damping controls are required to suppress vibrations caused by mechanical problems such as the rigidity and eccentricity of the gear 4 and the shaft 5, and therefore the rotating body 6 Could not be completely speed controlled.

Further, when driving a machine having a large driving capacity, for example, a shield machine (excavator) having a cutter rotating mechanism for tunnel excavation, a plurality of electric motors are connected to the rotating mechanism to share the load. Therefore, generally, only one large-capacity electric motor is used for driving.

Further, in a normal mechanical system, such as when driving an axle of an automobile mission tester from both ends, or when driving a shaft of a winding portion in a printing machine, etc., a plurality of electric motors are arranged. It is designed to drive by sharing the load. In the drive control device in which the load is shared by the n electric motors, as compared with the one driven by a single electric motor, both the control device and the electric motors having a capacity of 1 / n can be used. If the load is shared by n motors, 1
Even if the controller and motor of the stand are broken, the remaining (n-1)
It is possible to continue the operation of the mechanical system with one electric motor, improving the convenience of the system, the reliability of the system, etc., while reducing the total installation space of the mechanical system and reducing the cost. Because it will be possible.

Moreover, when a mechanical system is driven by a plurality of electric motors, vibration damping control can be actively performed. FIG. 4 is a block diagram showing an example of closed loop control for controlling the speed of a mechanical system using two electric motors.

When the first control device 101 drives the first electric motor 102 based on the speed command, the encoder 103
The rotation speed of the first electric motor 102 is detected by. As a result, the first gear is passed through the gear 104 and the shaft 105.
The speed of the rotating body (machine to be controlled) 6 connected to the electric motor 102 is controlled. On the other hand, also in the second control device 201, the second control device 201 performs the second speed control based on the same speed command as the first control device 101.
The electric motor 202 is driven, and the encoder 203
The rotation speed of the electric motor 202 is detected. This allows
The second electric motor 202 includes a gear 204 and a shaft 205.
Is connected to one end side of the rotating body 6 via the first electric motor 10
The speed control of the controlled machine 6 is performed while sharing the load with the control target machine 2.

[0009]

As described above, when a mechanical system is operated by a plurality of electric motors at a predetermined speed, a conventional method for controlling the speed of each electric motor while sharing the load is as follows. ) Droop control, (2)
Methods based on torque control and (3) pulse train control have been known.

(1) Droop control is a method in which the speed of one electric motor is controlled by a master control device, and the speed of other electric motors is drooped down by a slave control device in accordance with the size of the load to share the load. is there. The droop control function, which is built into a general-purpose drive device as standard, does not have high responsiveness, is difficult to adjust, and cannot perform precise speed control, so it does not require high-performance control accuracy. It is used only for winding devices.

That is, this method is applied to the control of a printing machine that requires high speed control accuracy, and the control of an electric motor that requires a speed response, such as a cutting machine and a testing machine for an automobile mission. There was a problem that I could not.

(2) Torque control means that when the master controller controls the speed of the electric motor, the torque command output is transmitted to the slave controller to give the same torque command to a plurality of electric motors. This is a method of sharing the load. This method has an advantage that it can be applied to control of a printing machine that requires high speed control accuracy and an electric motor that requires speed response.

However, when transmitting the torque command from the master control device to the slave control device, since it is exchanged as an analog signal, there is a problem that it is easily affected by noise in the transmission path. Moreover, when a filter is interposed as a measure against noise in the transmission path, not only the responsiveness is impaired, but also another new problem is caused, such as the filter becoming an unstable factor of control. Thus, in load sharing by torque control,
The command data to the slave side becomes inaccurate, and the torque balance is disturbed.

(3) The pulse train control is a method of driving the electric motor while controlling the position using the pulse train signal.
However, in the case where one machine is driven by load sharing by pulse train control, the PLC device must be arranged in a higher order and the pulse train signal must be transmitted to a plurality of control devices. In addition, since multiple motors are position-controlled by pulse train signals, if each is not mechanically configured accurately, it is difficult to obtain a fair load balance. It was only applicable.

An object of the present invention is to provide an electric motor drive control device capable of improving the reliability and maintainability of a mechanical system when a plurality of electric motors are driven at a predetermined speed to drive the mechanical system. It is in.

[0016]

In order to achieve the above object, there is provided a drive control device for driving a mechanical system while sharing a load with a plurality of electric motors. The drive control device for this electric motor connects an optical communication path between a master control device that controls the speed of one electric motor and a slave control device that controls the speed of the remaining electric motors. The control information of the electric motor is transmitted to the slave control device.

Since the optical communication path less affected by noise is used, the torque command, the exciting current command, the primary angular frequency command,
Even if the damping control measures are not taken on the mechanical system side, such as carrier switching timing information, command data required for vector control of the motor is given from the master control unit to the slave control units at high speed cycles to increase rigidity. It is possible to simplify the mechanical system adjustment by removing the factors of vibration and noise.

Further, if there is a delay element in the data to be transmitted, self-excited vibration or continuous vibration may occur. However, by performing data transfer via the optical communication path, compared to the response speed of the machine. Data can be transmitted at a sufficiently high-speed cycle, errors due to noise are eliminated, communication retry operation is suppressed, and stable operation becomes possible.

Further, since the PWM switching timing and the phases of the output currents of the three phases are completely the same between the master and slave devices, it is as if only one electric motor is used to drive one machine. Such a system can be configured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a drive control device for variable speed control of two electric motors.

This drive control device is a master control device 1.
00 and slave control device 200.
The master control device 100 drives the first electric motor 102 by a speed command ωr *, and the first electric motor 10
2 from the encoder 103 such as a pulse generator provided to detect the actual rotation speed
r is being fed back. Slave controller 20
0 is for driving the second electric motor 202 having the same capacity as that of the first electric motor 102, and the speed detection value ωr is fed back from the encoder 203 such as a pulse generator provided to detect the rotation speed of the second electric motor 202. Has been done. The master control device 100 and the slave control device 200 are coupled to each other by an optical transmission line 300, and various information described in detail later is transmitted to the master control device 10.
0 to the slave control device 200. Also,
The first and second electric motors 102 and 202 respectively include the gear 10
It is connected to both shafts of the rotating body (machine to be controlled) 6 by 4,204, and drives the rotating body 6 while sharing the load, so that one machine is driven by using only one electric motor. Configure the system.

Next, the configuration of the master control device 100 will be described. In FIG. 1, reference numeral 11 denotes an automatic speed controller (ASR), which is a speed command ωr * supplied from outside to the master control device 100 and an encoder 103.
A torque command τ * for speed adjustment is generated based on the speed detection value ωr fed back from
The automatic speed regulator 11 is connected to an automatic current regulator (ACR) 13 via a divider 12. In the automatic current controller 13, the q-axis voltage command Vq * and the d-axis voltage command Vd *
And a vector converter (VD) 1 via a delay compensator 14.
5 is being supplied. In this vector converter 15, U, V, W is calculated from the q-axis voltage command Vq * and the d-axis voltage command Vd *.
Three-phase voltage commands (Vu *, Vv *, Vw *) are generated.

Reference numeral 16 is a transistor switching circuit composed of six transistor switches, which is provided with a carrier signal generator 17 for generating a carrier signal of a predetermined frequency, and three-phase voltage commands (Vu *, Vv *, Vw
*) With a predetermined carrier wave (carrier signal),
Pulse width modulation (PWM) control for the primary current to the first electric motor 102 is performed. 18 is the first electric motor 10
It is a vector converter (VD) for generating a torque current detection value lq and an excitation current detection value ld from the detection values iu and iw of the primary current to 2 and the phase angle command θ *. Reference numeral 19 denotes a magnetic flux calculator for calculating the magnetic flux command Φ * from the detected speed value ωr. Based on the magnetic flux command Φ * calculated here, the magnetic flux adjuster (AΦR) 20 causes the excitation current command ld *
Is being calculated.

Reference numeral 21 is a frequency calculator, which is a magnetic flux command Φ.
* And the slip current command ωs * from the detected torque current value lq
Is being calculated. The calculated slip frequency command ωs * is
It is one input of the adder 22 and is added to the speed detection value ωr fed back from the encoder 103. The integrator 3 generates the phase angle command θ * from the primary angular frequency command ω1 * that is the addition result of the adder 22.

Further, an optical signal transmitter 24 is provided in the master control device 100, in which the torque command τ *, the magnetic flux command Φ *, and the exciting current command ld * generated in the above-mentioned circuits are provided. In addition to the phase angle command θ *, the primary angular frequency command ω1 *, the carrier information of the carrier signal generator 17 is converted into an optical signal and sent to the slave control device 200 via the optical transmission path 300.

Next, the configuration of the slave control device 200 will be described. The optical signal receiver 25 is connected to the optical transmission line 300, receives an optical signal from the master control device 100, converts it into various control information, and then transmits it to the slave control device 20.
It is adapted to be applied to the corresponding circuit portion which constitutes 0. The circuits in the slave control device 200 corresponding to the components in the master control device 100 are designated by the same reference numerals.

An adder 26 is a difference between the torque command τ * transferred from the master controller 100 and the torque command τ * generated by the automatic speed controller (ASR) 11 in the slave controller 200. Is being calculated. The phase angle corrector 27 calculates a corrected phase angle command θs * required by the slave control device 200 based on the phase angle command θ * and the primary angular frequency command ω1 * transferred from the master control device 100. To do.

The magnetic flux command Φ * transferred from the master controller 100 is input to the divider 12, and the exciting current command ld * transferred from the master controller 100 to the automatic current regulator (ACR). Has been entered. Further, the same carrier information as that of the master control device 100 is input to the carrier signal generator 17, so that the PWM control in the transistor switching circuit 16 is performed at the same timing.

Next, the operation of the drive control device configured as described above will be described. The master control device 100 and the slave control device 200 respectively include the first electric motor 10
2. Stable speed control can be performed by sharing the load on the same rotating body 6 while controlling the speed of the second electric motor 202. In the master control device 100,
When the speed command ωr * is input to the automatic speed controller 11,
It operates so as to converge the difference with the speed detection value ωr to zero. Further, the torque command τ * which is the output of the automatic speed regulator 11 is divided by the magnetic flux command Φ * in the divider 12 to obtain the torque current command lq *. The detection result of the output current of the first electric motor 102 and the phase angle command θ * are input to the vector converter 18, and the torque current direction component (q-axis component) and the magnetic flux current direction component (d-axis component) are vector-converted. The detected torque current value lq and the detected excitation current value ld corresponding to the above are output to the automatic current controller 13.

The automatic current controller 13 is adapted to the torque current command l.
It operates so as to converge the difference between q * and the detected torque current value lq and the difference between the excitation current command ld *, which is the output of the magnetic flux controller 20, and the detected excitation current value ld to zero. The automatic current controller 13 outputs the q-axis voltage command Vq * and the d-axis voltage command Vd * to the delay compensator 14, and the delay compensator 1
The delay-corrected voltage commands Vq and Vd are supplied to the vector converter (VD) 15 via 4. The vector converter (VD) 15 converts the PWM signals (Vu *, Vu) to the transistor switching circuit 16 by two-phase / three-phase conversion.
v *, Vw *) are generated.

In the transistor switching circuit 16,
U, V, W 3-phase voltage commands (Vu *, Vv *, Vw *)
By controlling ON / OFF of the six switching elements based on the carrier signal generator 17 and the carrier signal generator 17, the speed command ωr
A drive command signal corresponding to * can be output to the first electric motor 102. Note that the above vector control operation is general, and the slave control device 200 performs the same operation, but further description will be omitted.

Now, as shown in FIG. 1, the first electric motor 10
2 and the second electric motor 202, the reduction gears 104 and 204
Rotating body 6 such as shaft or axle of mechanical system via
In the case where the motors are connected with each other, it becomes a problem to accurately perform load sharing and vibration damping control between the two electric motors. In the above-described embodiment, the master controller 100 supplies the torque command τ * to the slave controller 200 via the optical transmission path 300 at a high speed cycle.
The same load sharing can be stably performed by the two electric motors 102 and 202.

Further, various control information of the master controller 100, that is, the magnetic flux command Φ *, the exciting current command ld *, the phase angle command θ *, and the primary angular frequency command ω1 * are transmitted to the slave controller 200 at high speed. Thus, the current control loop in the slave control device 200 and the arithmetic operations of the vector converters 15 and 18 are performed in the same cycle as the master control device 100 side.

As a result, the electric motor 202 connected to the slave control device 200 is compared to the conventional device in which the speed is not controlled in the slave control device that operates under current control, and control is insufficient for vibration generation. The speed is controlled by PG feedback, and the master control device 100,
Since the slave controller 200 uses closed loop control for speed control, vibration due to mechanical resonance or backlash can be suppressed only by the simple speed adjuster 11. Therefore, the load sharing on the slave control device 200 side can be surely executed even for the impact load.

Further, the carrier information of the carrier signal generator 17 is provided to the master controller 100 and the slave controller 2.
00, the torque pulsation due to the PWM control in the transistor switching circuit 16 is also generated at the same timing, and the twisting stress on the rotating body 6 can be effectively suppressed.

Further, the speed command ωr * for the master controller 100 is transmitted to the slave controller 200.
By inputting the same command as the above, the slave controller 200 not only operates the automatic speed adjuster 11 so that the difference from the speed detection value ωr fed back becomes zero, but also the torque from the master controller 100. Speed compensation is performed so that the output of the automatic speed controller 11 is added to the command τ *. As a result, the slave controller 20
Unlike the case where 0 is operated only by the torque command, the automatic speed adjuster 11 acts in the direction of damping the vibration associated with the speed fluctuation, so that effective vibration damping control can be executed.

The above-described embodiment is particularly suitable for driving a large machine such as a shield machine (excavator), driving an axle of an automobile mission testing machine, or a shaft of a winding section of a printing machine. It is suitable to be applied to a drive control device for an electric motor that drives a motor, and has the following advantages.

Firstly, since the speed control operation which is the same as the operation by one electric motor can be performed with respect to the impact load applied to the mechanical system, even if the load is shared by a plurality of electric motors, the control can be performed. It has the advantage of not degrading performance.

Secondly, since the control information is transmitted by using the optical communication system which is less affected by noise,
There is an advantage that the transmission line is noise-free. Third, since the master controller and the slave controller both perform speed control in a closed loop, active vibration suppression control is performed by a simple automatic speed controller (ASR) to generate mechanical system vibration. Can be dealt with.

Fourthly, since optical signal transmitters / receivers are arranged in the master control device and the slave control device, respectively, and they are connected to each other by an optical transmission line, an optical communication system is constructed, so that pulse train signals and analog signals Not only does shield wiring become unnecessary compared with the case where
There is an advantage that it becomes unnecessary.

Fifth, since the master controller transmits carrier information to the slave controller so as to realize PWM switching at the same timing, it is suitable for a mechanical system in which a plurality of electric motors are coupled. There is an advantage that continuous twisting stress can be removed.

Sixth, since the number of mechanical parts can be reduced as compared with a mechanical system driven by one electric motor,
Not only the installation space of the drive control device including the electric motor is reduced, but also the cost of the mechanical system can be reduced, the reliability can be improved, and the maintainability can be improved.

Seventh, since there is no need for precise adjustment of the machine and no adjustment for increasing the rigidity of the shaft, even if there is backlash in the gears of the gear, it does not cause vibration or noise. There is an advantage that the mechanical system can be easily adjusted.

In the above-described embodiment, the case where the slave control device is only one unit has been described, but the one in which the load is shared by three or more electric motors in the mechanical system is also connected to the master control device 100. This can be dealt with by adding the slave control device 200.

[0045]

As described above, the drive control device for an electric motor according to the present invention ensures reliability and maintainability of the mechanical system when driving the electric motor system by driving a plurality of electric motors at a predetermined speed. It can contribute to improvement.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a drive control device that controls a speed of an electric motor by a fully closed loop.

FIG. 2 is a block diagram showing the configuration of a drive control device that controls the speed of an electric motor by a fully closed loop.

FIG. 3 is a block diagram showing an example of semi-closed loop control in which the speed of a mechanical system is controlled by one electric motor.

FIG. 4 is a block diagram showing an example of closed-loop control for controlling the speed of a mechanical system using two electric motors.

[Explanation of symbols]

6 Rotating body (controlled machine) 100 master controller 102 first motor 103,203 encoder 104,204 Reduction gear 200 Slave controller 202 Second motor 300 optical transmission line 11 Automatic speed controller (ASR) 12 divider 13 Automatic current regulator (ACR) 14 Delay corrector 15,18 Vector converter (VD) 16 transistor switching circuit 17 Carrier signal generator 19 Magnetic flux calculator 21 Frequency calculator 20 Magnetic flux controller (AΦR) 22,26 adder 23 integrator 24 Optical signal transmitter 25 Optical signal receiver 27 Phase angle corrector

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Claims (4)

[Claims] 1. A drive control device for driving a mechanical system while sharing a load with a plurality of electric motors, wherein a master control device for speed control of one electric motor and a slave control device for speed control of the remaining electric motors are provided. A drive control device for an electric motor, characterized in that the control information of the electric motor is transmitted from the master control device to the slave control device at a predetermined timing by coupling through an optical communication path. 2. The master control device comprises an automatic speed adjusting means for calculating a torque command at a predetermined cycle based on a speed command and a speed detection value, and is calculated at a predetermined cycle for the slave control device. The drive control device for an electric motor according to claim 1, wherein the torque command is transmitted. 3. The control information of the electric motor includes a magnetic flux command (Φ *) and an exciting current command (ld) of the master controller.
*), Phase angle command (θ *), primary angular frequency command (ω1
The drive control device for the electric motor according to claim 1, further comprising *). 4. The plurality of electric motors are PWM-controlled by the master controller and the slave controller according to a three-phase voltage command, respectively, and carrier information for determining the timing of the PWM control by the master controller. 2. The drive control device for the electric motor according to claim 1, wherein the drive control device is configured to be shared with the slave control device.