JPH08251996A - Excitation controller for synchronous machine - Google Patents

Abstract

PURPOSE: To switch smoothly a field control which is performed from the starting of a synchronous machine to its voltage reaching a rated output voltage to an output voltage control which is performed after its voltage reaches the rated output voltage. CONSTITUTION: When a synchronous machine 1 is started[, the constant controls of its output voltage Vg and its rotating speed N are performed by a field current controller 12. After the output voltage Vg reaches a rated output voltage VGR, a voltage controlling signal SA of an excitation weakening side, i.e., a delayed phase side is selected by a constant-value selecting circuit 20. That is, by switching the field control using the field current controller 12 to the voltage control using an automatic voltage regulator 7, the sudden change of the output voltage Vg can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excitation control device for a synchronous machine activated by a thyristor activation device.

[0002]

2. Description of the Related Art A synchronous machine axially connected to a gas turbine is
When starting as a synchronous motor using the thyristor starter connected to the output of the synchronous machine, it is necessary to prevent the output voltage of the synchronous machine from exceeding the rated output voltage of the thyristor starter. The output torque of the gas turbine increases as the speed increases after ignition. The thyristor starter is
Mainly, the gas turbine is operating at a low speed, and it is necessary to give a large output torque to the gas turbine until the speed increases after ignition. Therefore, generally, the rated output voltage of the thyristor starter is set to be smaller than the rated output voltage VGR of the synchronous machine, and the output voltage of the synchronous machine is set with respect to the rotation speed as shown in FIG.
Control as shown in. That is, until the output voltage of the synchronous machine reaches the rated output voltage VGR of the thyristor starter, the ratio of the output voltage of the synchronous machine and the rotation speed is kept constant, and the output voltage of the synchronous machine reaches the rated output voltage of the thyristor starter. The output voltage of the synchronous machine is kept constant in the range exceeding the speed.

In this way, in a region where the rotational speed of the synchronous machine is small, while the sufficient output torque is obtained from the thyristor starter, the output voltage of the synchronous machine is suppressed to a constant level after the rotational speed increases, so that the thyristor can be controlled. The rated output voltage of the starter is reduced, which reduces the number of thyristor elements used in proportion to the rated output voltage.

A conventional excitation control device will be described with reference to the block diagram of FIG. Reference numeral 1 is a synchronous machine, and 2 is a field winding of the synchronous machine 1. The thyristor rectifier 3 converts the AC power supply Vs supplied via the excitation transformer 4 into a DC voltage Vf corresponding to the timing of the gate pulse signal SG output from the phase control circuit 5, and supplies it to the field winding 2. Supply.

The automatic voltage regulator 7 sets the output voltage Vg 'of the synchronous machine 1 detected through the voltage transformer 6 and the voltage setting device 8 for setting and outputting the target voltage Vr by the voltage setting device 8. The differential voltage detector 9 outputs a differential voltage signal Ve as compared with the target voltage Vr, and an amplifier circuit 10 that amplifies the differential voltage signal Ve and outputs a voltage control signal SA.

The field current controller 12 includes a field current setting device 13 for setting and outputting a target current Ifr, and a current transformer 11.
The field current If supplied via the field current setting device 13
The differential current detector 14 detects the differential current signal Ife by comparing it with the target current Ifr set in 1. and the amplifier circuit 15 that amplifies the differential current signal Ife and outputs the field current control signal SM.

The electromagnetic pickup 21 detects the rotation speed of the synchronous machine 1 and outputs a pulse signal Np having a frequency proportional to the rotation speed. The rotation speed detection circuit 22 receives the pulse signal Np and outputs the rotation speed signal N of the synchronous machine 1.

The switching circuit 23 has the voltage control signal S.
Input A, field current control signal SM and rotation speed signal N,
When the rotation speed signal N is equal to or lower than the preset switching rotation speed Ng, the field current control signal SM is selected,
When the rotation speed signal N exceeds the switching rotation speed Ng, the voltage control signal SA is selected and output as the phase control signal θ.

The phase control circuit 5 receives the phase control signal θ and supplies the gate pulse signal SG to the thyristor rectifier 3 at a timing corresponding to the phase control signal θ. With the above configuration, the rotation speed signal N of the synchronous machine 1 is switched to the rotation speed N.
Below s, the field current If of the synchronous machine 1 is controlled to be constant based on the value of the target current Ifr, and as a result, the ratio between the output voltage Vg of the synchronous machine 1 and the rotation speed signal N becomes constant. When the rotational speed signal N of the synchronous machine 1 exceeds the switching rotational speed Ng, the output voltage Vg of the synchronous machine 1 is controlled to be constant based on the value of the target voltage Vr.

[0010]

When the rotational speed signal N of the synchronous machine 1 reaches the switching rotational speed Ns and the phase control signal θ switches from the field current control signal SM to the voltage control signal SA, the synchronous machine 1 of the synchronous machine 1 is switched. The output voltage Vg does not always have a value sufficiently close to the target voltage Vr.

If Vg <Vr at the time of this switching, the voltage control signal SA is in a lead phase with respect to the field current control signal SM, and after switching, the output voltage Vg of the synchronous machine 1
Temporarily exceeds the target voltage Vr and suddenly changes in the upward direction.
At this time, the amount by which Vg exceeds Vr becomes large as SA advances and is largely biased toward the phase side due to the deviation between Vg and Vr. In such a control system, it is necessary to increase the rated output voltage of the thyristor starter in consideration of the temporary increase in the output voltage Vg of the synchronous machine 1 at the time of control switching, and as a result, the number of elements of the thyristor is increased. It's a bad thing.

An object of the present invention is to control the field current from the start of the synchronous machine until the rated output voltage VGR of the synchronous machine is reached and VGR.
This enables smooth switching of the constant control of the output voltage of the synchronous machine after reaching the value of.

[0013]

According to a first aspect of the present invention, there is provided an automatic voltage regulator for outputting an instruction for adjusting an output voltage of a synchronous machine, and an instruction for adjusting an electric quantity generated in a field winding of the synchronous machine. , A low-value selector that selects a low-value command from among the command of the automatic voltage regulator and the command of the field controller, and a pulse corresponding to the command selected by the low-value selector. A phase controller that outputs a command and a rectifier that controls the excitation amount of the synchronous machine based on the pulse command are provided.

The invention of claim 2 is characterized in that the field current is adjusted as an amount of electricity generated in the field winding. The invention of claim 3 is characterized in that the field voltage is adjusted as an amount of electricity generated in the field winding.

[0015]

By using the low value selector, a command to adjust the amount of electricity generated in the field winding output from the field controller during reaching the rated output voltage VGR of the synchronous machine from the start of the synchronous machine to reaching VGR. Switching of commands from the subsequent automatic voltage regulator is smoothly performed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an excitation control device showing a first embodiment. In the figure, the same reference numerals as those in FIG. 4 indicate the same or corresponding portions, and the explanation of the portions already described will be omitted.

The voltage control signal SA output from the automatic voltage regulator 7 and the field current control signal SM output from the field current controller 12 are selected by the low value selection circuit 20 on the delay phase side. It is output to the phase control circuit 5. As a result, the gate pulse signal SG output from the phase control circuit 5 is supplied to the thyristor rectifier 3.

With the above-described structure, when the excitation control device is operated, the field current control device 12 causes the field current control device 12 to start when the synchronous machine 1 is started.
Control is performed so that the ratio of the output voltage Vg of the synchronous machine and the rotation speed signal N becomes constant. Then, the synchronous machine 1 outputs the rated output voltage V
When the value reaches GR, the low value selection circuit 20 selects the voltage control signal SA which is the output signal on the weakening side of the excitation, and the voltage control is switched to the voltage control by the automatic voltage regulator 7.

According to the above configuration, the automatic voltage adjusting device 7 and the field current control device 12 can be smoothly switched, and the sudden change in the output voltage Vg of the synchronous machine 1 at the time of switching can be eliminated. be able to.

Next, a second embodiment of the present invention will be described with reference to the drawings. In the first embodiment, the automatic voltage regulator and the field current controller have been described, but the same control operation can be realized when the field voltage controller is used instead of the field current controller.

In the present embodiment, of the voltage control signal output from the automatic voltage regulator and the field voltage control signal output from the field voltage controller, the synchronous machine is driven based on the weaker excitation side signal. An excitation control device provided with a low value selection circuit for controlling the amount of excitation.

By adopting the low value selection circuit, the field voltage control signal of the field voltage controller during the time when the synchronous machine starts up to reach the rated output voltage VGR of the synchronous machine, and the automatic voltage regulator after the arrival of VGR. Switching of the voltage control signal is smoothly performed.

FIG. 2 is a block diagram of an excitation controller showing a second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, and the explanation of the portions already described will be omitted.

The field voltage controller 16 sets a target voltage Vfr and outputs the field voltage setter 17, and the field voltage Vf of the field winding 2 set by the field voltage setter 17.
Differential voltage detector 1 for detecting the differential voltage signal Vfe by comparing with fr
8 and an amplifier circuit 19 for amplifying the difference voltage signal Vfe and outputting the field voltage control signal SM.

The voltage control signal SA output from the automatic voltage regulator 7 and the field voltage control signal SM output from the field voltage controller 16 are selected by the low value selection circuit 20 on the delay phase side. It is output to the phase control circuit 5. As a result, the gate pulse signal SG output from the phase control circuit 5 is supplied to the thyristor rectifier 3.

With the above configuration, when the excitation control device is operated, when the synchronous machine 1 is started, the field voltage control device 16 causes
Control is performed so that the ratio of the output voltage Vg of the synchronous machine and the rotation speed signal N becomes constant. Then, the synchronous machine 1 outputs the rated output voltage V
When the value reaches GR, the low value selection circuit 20 selects the voltage control signal SA which is the output signal on the weakening side of the excitation, and the voltage control is switched to the voltage control by the automatic voltage regulator 7.

According to the above configuration, the automatic voltage adjusting device 7 and the field voltage control device 16 can be smoothly switched, and the sudden change in the output voltage Vg of the synchronous machine 1 at the time of switching can be eliminated. be able to.

[0028]

According to the present invention, voltage control by an automatic voltage regulator and field current control by a field voltage controller, or voltage control by an automatic voltage regulator and field voltage control by a field voltage controller. Can be switched reliably and smoothly.

Further, since the rated output voltage of the thyristor starting device can be reduced, the number of elements of the thyristor used in proportion to the rated output voltage can be reduced and the cost of the thyristor starting device can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an excitation control device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an excitation control device according to a second embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a generator voltage and a rotation speed.

FIG. 4 is a configuration diagram of a conventional excitation control device.

[Explanation of symbols]

1 ... Synchronous machine, 2 ... Field winding, 3 ... Thyristor rectifier, 7
... Automatic voltage regulator, 12 ... Field current controller, 16 ...
Field voltage control device, 20 ... Low value selection circuit

Claims (3)

[Claims] 1. An automatic voltage regulator that outputs a command to adjust the output voltage of a synchronous machine, a field controller that outputs a command to adjust the amount of electricity generated in the field winding of the synchronous machine, and the automatic voltage adjustment. Value selector for selecting a low value command from among the command of the field controller and the command of the field controller, a phase controller for outputting a pulse command according to the command selected by the low value selector, and the pulse An excitation control device for a synchronous machine, comprising: a rectifier that controls an excitation amount of the synchronous machine based on a command. 2. An automatic voltage adjuster for outputting a command for adjusting an output voltage of a synchronous machine, a field current controller for outputting a command for adjusting a field current of the synchronous machine, and an automatic voltage adjuster for the automatic voltage adjuster. A low-value selector that selects a low-value command from among the command and the command of the field current controller, a phase controller that outputs a pulse command according to the command selected by the low-value selector, and An excitation control device for a synchronous machine, comprising: a rectifier that controls an excitation amount of the synchronous machine based on a pulse command. 3. An automatic voltage regulator that outputs a command to adjust the output voltage of the synchronous machine, a field voltage controller that outputs a command to adjust the field voltage of the synchronous machine, and an automatic voltage regulator of the automatic voltage adjuster. A low-value selector that selects a low-value command from among the command and the command of the field voltage controller, a phase controller that outputs a pulse command according to the command selected by the low-value selector, and An excitation control device for a synchronous machine, comprising: a rectifier that controls an excitation amount of the synchronous machine based on a pulse command.