JPS633668A - Control mode switching controller of motor - Google Patents

Abstract

PURPOSE:To suppress torque variation at control mode switching time, by a method wherein the magnitude of allowable variation rate of command signal is switched between at the control mode switching time and after switching. CONSTITUTION:Contact e is inserted to output side of a current command device 14 and closed at current control mode time, and contact e' is inserted to output side of a speed control device 12 and closed at speed control mode time. If control mode is switched by automatic speed control ASR/automatic current control ACR switching signal Z, a one-shot multivibrator 19 generates pulses of a definite time width T in synchronization with rise of the ASR/ACR changing signal Z, and contact f is opened and contact f' is closed while pulses are being generated thereby a current variation rate control device 16 is coupled. Since the current variation rate control device 16 reduces variation rate of the input signal, torque variation of a DC motor 1 at switching time can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control mode switching control device for realizing shockless switching by preventing torque fluctuations that occur when switching control modes of an electric motor.

[Conventional technology]

FIG. 4 shows, for example, the automatic speed control a'D (ASR)/automatic current control (
ACR) is a block diagram of the switching control system, in which 1 is a DC motor, 2 is a speed detector, 3 is a current detector, 4 is a current control device, 5 is a speed control device 6 is a current command device, and 7 is a speed command 8 is a storage device for storing the current feedback value;
9 is a storage device for storing speed feedback values, a-
d is a normally open contact, τ, and the bottom is a normally closed contact; in the ACR control mode, contacts a and c are OFF, and contacts s and d are ON.

In this configuration, when switching from ACR control mode to ASR control mode, contact a is turned on, contact 2 is turned off, and at the moment contact a is turned on, the speed feedback value Nf at that time is stored in the storage device 9, and remains unchanged. It is input to the speed command device 7 and becomes the speed command value Np. The output of the speed control device 5 becomes the manual power of the current control device 40 and is compared with the t-current feedback value If, but since it is almost O at this point, the current command value is ip is immediately 0 as shown in Figure 5.
Instead, the current command value ip is decreased little by little, and when the current command value ip reaches 0, contact d is turned OFF to cut off Ip. Contact a
' After IJ<ON, contact C is turned ON after a certain period of time TO, and the speed command value Np is changed to the speed desired by the speed command device 7. When switching from the ACR control mode to the ASR control mode, the current feedback value If stored in the storage device 8 at the moment when the contact turns ON is used as the current command value Ip, and after a certain period of time TO, the current feedback value If is used as the current command value Ip. 6 changes to the desired current value command value.

[Problem that the invention seeks to solve]

In this way, in the conventional method described above, the feedback value immediately before switching the control mode is stored, and this stored feedback value is used as the command value after switching the control mode. Therefore, if the gain of the speed control system is increased, current fluctuations occur due to ripple errors, and the circuit configuration becomes complicated.

This invention was made to solve the above problem, and an object thereof is to obtain a control mode switching control device for an electric motor that can effectively suppress torque fluctuations when switching control modes with a simple circuit configuration. do.

[Means to solve the problem]

In order to achieve the above object, the present invention provides two current change rate controllers with different current change rate setting values at the front stage of a current control device that takes the deviation between the current reference value and the current feedback value, and controls the control mode. The configuration is such that a current change rate controller with a small current change rate setting value is connected to the circuit in place of the current change rate controller with a large current change rate setting value only during a certain period of time at the time of switching.

[Effect]

In this invention, since the magnitude of the allowable change rate of the command signal is switched between when switching the control mode and after switching, by keeping the allowable change rate when switching the control mode sufficiently small, it is possible to Torque fluctuations can be suppressed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 100 is a power converter (thyristor rectifier), 10 is a current control device, 11 is a gate device, 12 is a speed control device, 13 is a speed command device, and 14 is a current command device. 15 is a first current change rate controller (current change rate set value A), 16 is a second current change rate controller (current change rate set value B<A), 17 is a switch for switching control modes, 18
is the switch for switching the current change rate side j■ device, 19 is the switch 1
This is a switching signal generator (one shot multi) for 8.

The switch 17 has a normally open contact e and a normally closed contact, and has an ASR/
A switching signal ratio operation is performed on the ACR switching signal Z. Normally open contact e
is inserted into the output side of the current command device 14 and is closed during the ACR control mode, and the normally closed contact i is inserted into the output side of the speed control device 12 and closed during the ASR control mode. The switch 18 for switching the current change rate setting device has a normally open contact f and a normally closed contact bottom, and performs a switching operation based on the output of the one-shot multi 19. The normally closed contact T is located on the input/output side of the current change rate controller 15 and is opened when the output of the one-shot multi 19 is opened, and the normally open contact f is located on the input/output side of the current change rate controller 16 and is opened for the one-shot The circuit is closed during output of the multi-channel 19. The fun shot multi 19 generates a pulse with a predetermined time width T in synchronization with the timing of the switching signal ratio of the ASR/ACR switching signal Z.

Next, the operation of this device will be explained with reference to the waveform time chart shown in FIG.

In this configuration, in the ACR control mode, the lower and lower contacts are closed, and the command value (signal) from the current command device 14 is
Ipx is supplied to the current control device 10 through the current change rate controller 15. The current control device 10 uses this command value 1px as a current reference Ip to set a current feedback value If.
The gate pulse generation phase of the gate device 11 is controlled so that the deviation becomes O.

In this state, when switching to ASR control mode is performed by the ASR/ACR switching signal, contact e is opened and contact e is closed, current command unit 14 is disconnected, and speed control device 12 is connected to the circuit. be done. At the same time, the one-shot multi 19 generates a pulse with a fixed time width T in synchronization with the rise of the ASR/ACR switching signal, and during the generation of the pulse, the contact f is open and the contact T is closed, so that the ASR/ACR switching signal Z During the same time period T as the switching signal, the output of the speed control device 12 that receives the deviation between the speed feedback value Nf and the command value Np from the speed command device 13 is coupled to the current change rate controller 16.

Since this current change rate controller 16 suppresses the change rate of the input signal to be less than the set current change rate B, the current change rate set value B
By appropriately reducing the current reference I, even if the command value Ipx changes in large steps when switching control modes
Since the change in p can be made sufficiently gradual, A
Torque fluctuations in the DC motor 1 when switching to the SR mode are suppressed, and shockless switching is realized.

Similarly, when switching from ASR control mode to ACR control mode, one-shot multi 19 generates a pulse in synchronization with the switching signal of ASR/ACR switching signal Z, and this pulse controls switch 18 to maintain a constant The command value 1p is passed through the second current change rate controller 16 only during the time T.
Since x is supplied to the current control device 10, the torque fluctuation of the DC motor 1 at the time of switching to the ACR control mode is suppressed.

The above embodiment is an ASR/ACR control mode switching control device, but as shown in FIG.
A similar effect can be obtained by implementing switching control of the R control mode. In the figure, 20 is a voltage detector, 21
2 is a voltage command device, and 22 is a voltage control device, which performs voltage control calculations in response to the deviation between the output of the voltage detector 20 and the output of the voltage command device 21.

〔Effect of the invention〕

As explained above, this invention switches the control mode without using the feedback value immediately before switching as the command value when switching the control mode, so the control mode can be switched without shock without causing torque fluctuations due to ripples in the feedback signal. Since the current change rate of the command value is simply suppressed to a sufficiently small level when switching the control mode, the above effects can be obtained with a simple circuit configuration.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a waveform time chart in the above embodiment, Fig. 3 is a block diagram showing another embodiment of the invention, and Fig. 4 is a conventional A
FIG. 5, which is a block diagram of the SR-ACR switching control device, is a waveform time chart in the conventional example. In the figure, 10-current control device, 12-speed control device, 13-speed command device, 14-current command device, 15.16-
・Current change rate controller, 19-・-One-shot multi. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] a speed control device that receives a deviation between the output of the speed command device and the speed feedback value; a first current change rate controller to which the output of the speed control device and the output of the current command device are switched and input;
A current control device that receives a deviation signal between the output of the current change rate controller and a current feedback value, a gate device that receives the output of the current control device and sends a gate signal to a power converter that drives a motor, and a control mode switch. a second current change rate controller connected to the circuit in place of the first current change rate controller only for a certain period of time; the current change rate setting of the second current change rate controller; A control mode switching control device for an electric motor, characterized in that the value is sufficiently small.