JP2601926B2 - Multiplexed excitation controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a multiplex excitation control device for a synchronous machine having high controllability and high reliability.

(Prior Art) Improving the Reliability of an Excitation Controller Exciting a Synchronous Machine 1
As one method, the excitation control device is tripled. In this method, excitation control is performed by an intermediate value of the outputs of three excitation control devices, and a conventional example is shown in FIG.

The output voltage VG of the synchronous machine 1 is converted into a predetermined excitation power supply Vac by an excitation transformer 2 and applied to a thyristor rectifier 3 and also applied to three excitation control devices 4, 5, and 6.

In excitation control device 4, 5, 6, the voltage reference signal voltage setter 41, 51, 61 is based on the increase or decrease command V _ID from outside VR1, VR
2, VR3 is increased or decreased, and the voltage detection signals VR1, VR
2, VR3 are output to comparators 43, 53, 63, respectively.

The voltage detectors 42, 52, and 62 detect the output voltage VG of the synchronous machine 1, and the voltage detection signals VG1, VG2, and VG3 are input to the comparators 43, 53, and 63, respectively.

The comparators 43, 53, 63 detect a deviation between the voltage reference signals VR1, VR2, VR3 and the voltage detection signals VG1, VG2, VG3, and output the deviation signals VE1, VE2, VE3 to the automatic voltage regulator 44, Output to 54,64.

Automatic voltage regulators 44, 54, 64 are provided with deviation signals VE1, VE2, VE3.
, And outputs the respective phase control command signals VA1, VA2, VA3 to the pulse generators 45, 55, 65.

The pulse generators 45, 55, and 65 select an intermediate value among the three applied phase control command signals VA1, VA2, and VA3, and generate timings corresponding to the selected phase control command signals VA1, VA2, and VA3. To form firing pulses PA1, PA2, PA3, which are connected by wired-OR and applied to the thyristor rectifier 3.

When the thyristor rectifier 3 inputs the firing pulses PA1, PA2, PA3 connected by a wired OR, the rectifier arm is fired in accordance with those inputs, thereby rectifying the excitation power supply Vac, and A direct current is applied to the winding 7.

Here, FIG. 2 shows only one phase of the power supply. When the power supply is composed of three phases of U-phase, V-phase and W-phase, each excitation control device 4, 5, 6 has 6 A system processing system is provided, and firing pulses PA1, PA2, PA3 are formed for each phase.

With the above configuration, the excitation control devices 4, 5, and 6 of the third system output the firing pulses PA1, PA2, and PA3 at timings corresponding to the intermediate values of the phase control command signals VA1, VA2, and VA3.

When the three excitation control devices 4, 5, and 6 are all operating normally, normal control can be performed by any of the phase control command signals VA1, VA2, and VA3. Normal excitation control can be performed also by the intermediate value of the command signals VA1, VA2, VA3.

Now, consider a case in which one of the three excitation control devices 4, 5, and 6 has failed. Even if, for example, the phase control command signal VA1 becomes abnormal due to the failure of the excitation control device 4, if the phase control command signals VA2 and VA3 are normal, the normal phase control command signal VA2 which is an intermediate value thereof is obtained. Or, normal excitation control can be performed by VA3. Further, in this case, even if the intermediate value of the phase control command signals VA1, VA2, and VA3 becomes the abnormal signal VA1, the normal phase control command signal V
Since the value is between A2 and VA3, normal excitation control can be performed. From the above, it can be understood that normal excitation control can be performed by the normal excitation control devices 5 and 6 with respect to the failure of the excitation control device 4, for example. Note that the excitation control device 5
The same holds true for the failure of 6 or 6.

In this way, when a triple excitation control device is used, a failure occurs in any one of the excitation control devices 4, 5, and 6, and the phase control command signal of that system is output. Even in the case of an abnormality, if the other two excitation control devices are normal, the synchronous machine 1 can be appropriately excited.

(Problems to be solved by the invention) However, the conventional control device has the following problems.

The output voltage control of the synchronous machine 1 is so-called feedback control, and the steady-state gain of the open loop is about 200 or more. Therefore, variations in the voltage detection signals VG1, VG2, VG3 caused by variations in the characteristics of the voltage detectors 42, 52, 62 are:
After taking deviations from the voltage reference signals VR1, VR2, VR3 in the comparators 43, 53, 63, the signals are amplified to the constant gain times by the automatic voltage regulators 44, 54, 64, so that the phase control command signals VA1, VA2, VA3
Will have considerable variation. Therefore, the excitation control device that has output the intermediate value of the phase control command signal breaks down, and when the control is switched to one of the other two normal excitation control devices, the phase control command signal varies. As a result, the intermediate value of the phase control command signal changes abruptly, and disturbance occurs in the excitation control using the intermediate value of the phase control command signal. Therefore, the switching of the control system is not performed smoothly.

Voltage setting unit 41, 51, 61 of the excitation control device 4, 5 and 6 on the basis of the increase or decrease command V _ID from the outside is performed to increase or decrease the voltage reference signal VR1, VR2, VR3, but each is independently three excitation control device due to the operation, variations between the voltage reference signal VR1, VR2, VR3 even for the same increase or decrease command V _ID is generated in. As in the case of the above, the variation of the voltage reference signals VR1, VR2, VR3 is amplified to the steady gain of the voltage control system by the phase control command signals VA1, VA2, VA3 and becomes a large variation. Therefore, when the excitation control device that has output the intermediate value of the phase control command fails, the control is not smoothly switched to another normal excitation control device.

In order to solve the problems of the conventional control device described above, conventionally, the following measures have been taken.

FIG. 3 shows a conventional example of an excitation control device in which such measures are taken, and the same parts as in FIG. 2 are omitted. In the figure, FIG. 2 and the first reference numerals indicate the same or corresponding parts,
The difference from the conventional configuration shown in FIG. 2 is that three excitation control devices are provided with intermediate value selection circuits 46, 56, 66 and error detectors 47, 57, 67.

The intermediate value selection circuits 46, 56, 66 receive the deviation signals VE1, VE2, VE3 output from the comparators 43, 53, 63, and input the deviation signals VE1, VE3.
2. Output intermediate values VM1, VM2, VM3 of VE3. Error detector 47,5
7, 67 receive the intermediate values VM1, VM2, VM3 and the deviation signals VE1, VE2, VE3, and output the difference between them as error signals VER1, VER2, VER3. The voltage setting units 41, 51, 61 receive the error signals VER1, VER2, VER3 and increase or decrease the voltage reference signals VR1, VR2, VR3 according to the sign of the error signal.

By configuring the excitation control devices as described above, each of the excitation control devices 4, 5, and 6 outputs the error signal VER1, VER2, when the deviation signal of its own system among the deviation signals VE1, VE2, VE3 is the maximum.
VER3 becomes negative, reduces the voltage reference signals VR1, VR2, VR3,
When the deviation signal of the own system is an intermediate value, error signals VER1, VER2, VE
R3 becomes 0 and the voltage reference signals VR1, VR2, VR3 are maintained as they are,
When the deviation signal of the own system is the minimum, the error signals VER1, VER2, VER3
Becomes positive and increases the voltage reference signals VR1, VR2, VR3. As a result, to reduce the variation of the deviation signal VE1, VE2, VE3 generated for variations in the increase or decrease of the voltage reference signal VR1, VR2, VR3 by increasing or decreasing the command V _ID from variation or external voltage detector 42, 52, 62 Therefore, the above-described problem of the conventional excitation control device can be solved.

However, this embodiment has the following problem.

Voltage reference signals VR1, VR which are outputs of the voltage setting devices 41, 51, 61
2. Since VR3 is the set value of the output voltage VG of the synchronous machine to be controlled, the three voltage reference signals as a whole must not shift in the increasing or decreasing direction unless there is an external increase / decrease command. However, in this embodiment, the deviation signals VE1, VE
2, VE3 can be balanced, but the voltage reference signal V
There is no guarantee that the levels of R1, VR2 and VR3 are kept constant as a whole.

A feature of the triple excitation control device is that control can be continued by the remaining two systems with respect to failure of a single system among the three excitation control devices. However,
In this embodiment, continuation of control is not guaranteed when a failure occurs. This is because, for example, it is assumed that the excitation control device 6 fails and the deviation signal VE3 changes, and VE3 << VE1, VE2. Excitation controllers 4 and 5 are voltage reference signals for systems with large deviation signals VE1 and VE2
VR1 and VR2 can be reduced but not increased. For this reason, the voltage reference signal gradually decreases despite no external increase / decrease command.

Further, a description will be given of an example of an improvement conventionally performed to solve the problems of the excitation control device as described above.

FIG. 4 is a configuration diagram of an excitation control device showing an improved example thereof, and the same parts as those of the conventional configuration of FIG. 2 are omitted. In the figure, the same reference numerals as those in FIG. 2 denote the same or corresponding parts, and the difference from the conventional configuration in FIG. 2 is that three excitation control devices are provided with reference signal intermediate value selection circuits 4A, 5A, 6A and detection signal intermediate circuits. This is the point that the selection circuits 4B, 5B, and 6B are provided.

The reference signal intermediate value selection circuits 4A, 5A, 6A
1, VR2, VR3, and the intermediate value Vm1, V
Outputs m2 and Vm3. The intermediate values Vm1, Vm2, Vm3 are the voltage setting devices 41,
51, 61, the voltage setting devices 41, 51, 61 are intermediate values Vm1, Vm
2. Output voltage reference signals VR1, VR2, VR3 as signals that follow Vm3. The detection signal intermediate value selection circuits 4B, 5B, 6B receive the voltage detection signals VG1, VG2, VG3 and output intermediate values VD1, VD2, VD3 of these voltage detection signals. The intermediate values VD1, VD2, VD3 are input to the comparators 43, 53, 63 together with the voltage reference signal, and are input to the comparators 43, 53, 63.
63 outputs these deviation signals VE1, VE2, VE3.

By configuring the excitation control device as described above, each of the voltage reference signals VR1, VR2, and VR3 can be maintained at a certain common value. Furthermore, the intermediate values VD1, VD2,
Since there is almost no variation in VD3, the deviation signals VE1, V
E2, VE3 can be balanced. Further, even if a failure occurs in a single system among the three excitation control devices, control can be continued by the remaining two systems.

However, this improved example also has the following problems.

Considering the case where the output voltage VG changes, if there is a time delay before the voltage detection signal of another system is transmitted to the own system, the intermediate value VD1 of the deviated voltage detection signals VG1, VG2, VG3 , V
D2 and VD3 are any of the voltage detection signals of the other system that arrived with a delay in time, and control is performed using the intermediate value of the delay in this configuration. This configuration has a problem in the responsiveness of the control system. .

It is further assumed that the excitation control device having the intermediate value VG2 of the voltage detection signals VG1, VG2, VG3 fails. If the relationship of VG1 <VG2 <VG3 becomes VG1 <VG3 <VG2 due to the sudden change of VG2, the intermediate value of the voltage detection signal suddenly changes from VG2 to VG3, and this causes disturbance to the excitation control device.

The present invention solves such a problem and provides more controllability,
It is an object of the present invention to provide a highly reliable multiplex excitation control device.

[Constitution of the Invention] (Means for Solving the Problems) In the present invention, in a triple excitation control device, a voltage reference signal and a voltage detection signal of each excitation control device are converted into voltage reference signals of three excitation control devices. And the intermediate value of the voltage detection signal to balance the deviation signals of the three systems, and thus the phase control command.

(Operation) Therefore, even if the control system that is actually performing voltage control fails, the intermediate value of the phase control command is output, and switching to another normal control system can be performed smoothly, so that excitation control is performed. Controllability and reliability can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram of an excitation control device showing one embodiment of the present invention, and the same parts as those of the conventional configuration of FIG. 2 are omitted. 1, the same reference numerals as those in FIG. 2 denote the same or corresponding parts. The difference from the conventional configuration of FIG.
Reference signal intermediate value selection circuits 4A, 5A, 6A that input voltage reference signals VR1, VR2, VR3 to the two excitation control devices 4, 5, 6 and output intermediate values Vm1, Vm2, Vm3 of these voltage reference signals. , Voltage detection signals VG1, VG2, and VG3, and the intermediate value V
Detection signal intermediate value selection circuits 4B, 5B, 6B that output M1, VM2, VM3
And the voltage detection signals VG1, VG2, VG3 and the intermediate values VM1, VM2, VM3 of the voltage detection signals, and their error signals VH1, VH
Error detection circuits 4C, 5C, 6C that output H2, VH3 and error signal VH
1, VH2, VH3, and voltage correctors 4D, 5D, 6D that output voltage correction signals VC1, VC2, VC3 that follow these error signals,
Voltage detection signals VG1, VG2, VG3 and voltage correction signals VC1, VC2, VC3
And the voltage detection values VD1, VD2,
The point is that it includes subtractors 4E, 5E, and 6E that output VD3.

The intermediate values Vm1, Vm2, Vm3 of the voltage reference signals VR1, VR2, VR3 are input to the voltage setting devices 41, 51, 61, and the voltage setting devices 41, 51, 61 are signals that follow the intermediate values Vm1, Vm2, Vm3. Voltage reference signal VR1, V
Outputs R2 and VR3. Further, the voltage detection values VD1, VD2, VD3 are input to the comparators 43, 53, 63 together with the voltage reference signals VR1, VR2, VR3, and the comparators 43, 53, 63 output their deviation signals VE1, VE2, VE3.
Is configured to be output.

With the above configuration, each of the voltage reference signals VR1, VR2, VR3 can have a common value. Further, even when one excitation control device fails and the voltage reference signal of the system suddenly changes, the voltage reference signal of another normal system can be held. Because, for example, the voltage reference signal
When VR1, VR2 and VR3 are equal, V
It is assumed that R3 changes and VR1 = VR2> VR3. At this time, the intermediate values Vm1 and Vm2 of the voltage reference signals VR1, VR2 and VR3 in the excitation control devices 4 and 5 still remain equal to the voltage reference signals VR1 and VR2, and the voltage reference signals VR1 and V2 follow the intermediate values Vm1 and Vm2. V
R2 is also unchanged.

On the other hand, variations in the voltage detection signals VG1, VG2, VG3 due to variations in the characteristics of the voltage detectors 42, 52, 62 are corrected by the voltage correctors 4D, 5D, 6
Corrected by the voltage correction signals VC1, VC2, VC3 which are the outputs of D,
Voltage detection values VD1, VD2, and VD3 can be balanced. This is because, for example, in a steady state, the relationship between the voltage detection signals is VG1 <VG2 <VG3. At this time, the intermediate value V
M1, VM2, VM3 are all equal to VG2 and the error signals VH1, VH2, V
H3 and the voltage correction signals VC1, VC2, VC3 that follow it have the relationship shown in equation (1).

Therefore, the voltage detection values VD1, VD2, and VD3 are all equal to VG2.

Next, consider the case where the voltage detection signals VG1, VG2, VG3 change. At this time, as a characteristic of the voltage correctors 4D, 5D, and 6D, if the voltage correction signals VC1, VC2, and VC3 are made to sufficiently slowly follow the error signals VH1, VH2, and VH3,
Changes in the voltage detection signals VG1, VG2, VG3 during the transition can be transmitted to the voltage detection values VD1, VD2, VD3 almost as they are.

Further, consider a case where the excitation control device having the intermediate value VG2 of the voltage detection signals VG1, VG2, VG3 fails. VG1 <VG2 <VG3
Even if the relationship becomes VG1 <VG3 <VG2 due to a sudden change in VG2, the voltage control signals VC1, VC2, and VC3 do not suddenly change, so that the voltage control is smoothly continued by the excitation control devices 4 and 6. However, at this time, the intermediate value of the voltage detection signal
To switch to G3, the error signals VH1 and VH3 of the excitation controllers 4 and 6 are
It changes by the difference between VG3 and normal VG2, and the voltage correction signals VC1 and VC3 change accordingly.
2. The voltage detection characteristic changes by the amount of the variation of VG3. However, there is no further characteristic change, and the control can be continued by the two normal excitation control devices.

The above holds true when the variations of the voltage detection signals VD1, VG2, and VG3 have any magnitude relation.

In this way, by balancing the three systems of the voltage reference signals VR1, VR2, VR3 and the voltage reference values VD1, VD2, VD3, it is possible to eliminate variations in the deviation signals VE1, VE2, VE3.

By using the above-described configuration in a triple excitation control device, a failure of a certain excitation control device can be performed normally without causing a control delay from the occurrence of a failure or disturbance when switching a control system. Control can be continued. A multiplex excitation control device having high controllability and high reliability can be configured.

In the present invention, the reference signal intermediate value selection circuits 4A, 5A, 6A of the voltage reference signal, the detection signal intermediate value selection circuits 4B, 5B, 6B of the voltage detection signal and the voltage corrector are used for the output voltage control of the synchronous machine 1. Although 4D, 5D, and 6D are provided to balance the deviation signals VE1, VE2, and VE3, this can also be used for controlling the field voltage of the synchronous machine 1. In this case, the input signals of the voltage detectors 42, 52, and 62 may be changed from the output voltage VG of the synchronous machine 1 to the field voltage VF with respect to the embodiment of FIG.

In this way, even in the field voltage control of the synchronous machine 1, the control system can be switched smoothly when a failure occurs by balancing the deviation signals VE1, VE2, VE3.

[Effects of the Invention] As described above, according to the present invention, an intermediate value selection circuit for a voltage reference signal and a voltage detection signal and a voltage corrector are provided for a triple excitation control device, and three excitation control devices are provided. Since the deviation signals are balanced, control can be smoothly connected to the failure of a single excitation control unit by another normal two-system excitation control unit. A multiplex excitation control device can be configured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing one embodiment of the present invention, FIG. 2 is a configuration diagram of a conventional excitation control device, and FIG. 3 solves a problem of the conventional excitation control device. FIG. 4 is a configuration diagram showing an example of a device that can be considered for this purpose, and FIG. 4 is a configuration diagram showing an example of an improvement conventionally used. 1: Synchronous machine, 4, 5, 6: Excitation controller, 4A, 5A, 6A: Intermediate value selection circuit, 4B, 5B, 6B: Intermediate value selection circuit, 4C, 5C, 6C: Voltage corrector.

Claims (1)

(57) [Claims] A voltage detector that detects an output voltage of the synchronous machine and outputs a voltage detection signal; a voltage setter that increases or decreases a voltage reference signal based on an increase / decrease command; the voltage reference signal and the voltage detection signal And outputs a deviation signal by inputting
A multiplexed excitation control device provided with at least three systems of excitation control devices including an automatic voltage adjustment device that receives the deviation signal and outputs a phase control command signal that adjusts the output voltage of the synchronous machine according to the deviation signal. The voltage reference signals of the three systems are input to the excitation control devices of the respective systems, an intermediate value thereof is selected as a voltage reference signal intermediate value, and the voltage reference signal output from the voltage setter of the own system is followed. A voltage reference signal intermediate value selection circuit, a voltage detection signal intermediate value selection circuit that receives the three voltage detection signals, selects and outputs the intermediate value as a voltage detection signal intermediate value, and a voltage detection signal intermediate value A voltage correction signal generator that generates a voltage correction signal that follows an error signal between the voltage correction signal and the voltage detection signal; A multiplex excitation control device, comprising: a subtractor for inputting instead of a detection signal.