JP2541478Y2 - Brushless Exciter for Synchronous Generator - Google Patents

Description

[Detailed description of the invention]

[Purpose of the invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless exciter for a synchronous generator, and more particularly to a brushless exciter for a synchronous generator which performs high-speed control for reducing the generator terminal voltage.

[0003]

2. Description of the Related Art Synchronous generators (hereinafter referred to as "generators") are widely used because terminal voltages can be easily controlled by adjusting an exciting current flowing through a field circuit. In particular, a brushless excitation type generator that supplies an excitation current without using a brush by an AC exciter (hereinafter referred to as an exciter) and a rotary rectifier is widely used because it is maintenance-free.

FIG. 3 shows a configuration diagram of a generally used brushless excitation device of a generator. In FIG. 3, 1 is a generator, 1a is a generator armature winding, 1b is a generator field winding, 2 is an exciter, 2a is an exciter armature winding, and 2b is an exciter field. The winding 3 is a rotary rectifier, 4 is a voltage detector, 5 is a terminal voltage setter, 6a is an automatic voltage regulator, 6b is a power amplifier, and 7 is a bus. VG is the terminal voltage command value of the generator, VG1 is the effective terminal voltage value of the generator 1, Vf1 is the excitation voltage of the generator 1, if1 is the excitation current of the generator 1, Vf2 is the excitation voltage of the exciter 2, and if2 Is an exciting current of the exciter 2.

Next, the operation of the above-described conventional brushless excitation device will be described. The terminal voltage setting device 5 sets a terminal voltage command value VG of the generator 1. The automatic voltage regulator 6a controls the excitation voltage Vf2 of the exciter 2 so that the terminal voltage effective value VG1 of the generator 1 detected by the voltage detector 4 matches the terminal voltage command value VG. The power amplifier 6b amplifies the excitation voltage command signal of the automatic voltage regulator 6a and supplies it to the exciter 2. When the excitation voltage Vf2 is applied to the exciter 2, the excitation current if2 flows to generate a terminal voltage. The AC terminal voltage is rectified by the rotary rectifier 3 to generate the excitation voltage Vf1 of the generator 1.
Becomes Due to the excitation voltage Vf1, the excitation current if1 flows through the generator 1, and the generator 1 which matches the terminal voltage command value VG
Generates the terminal voltage effective value VG1. Electric power of the generator 1 is supplied to a power system and a load through a bus 7. According to this configuration, if the generator field winding 1b, the rotary rectifier 3, and the exciter armature winding 2a are arranged on the rotor, the excitation current can be supplied to the generator 1 without using a brush or the like. Is possible and maintenance-free.

[0006]

The conventional brushless exciter configured as described above has been used as a generator for supplying substantially constant active power and reactive power with little fluctuation to the system and load. . In such an application, there was no problem even if the control response of the generator terminal voltage was not so fast. However, a generator that requires a fast control response, for example, a system for stabilizing a system, employs a system in which an exciting current is directly supplied from a power amplifier using a brush. However, recently, in order to save labor and maintenance, an excitation method without using a brush has been required even for a generator for which a fast control response is required.

FIG. 4 is an operation waveform diagram for explaining the operation of the conventional brushless excitation device. Hereinafter, problems of the conventional brushless exciter will be described with reference to the operation waveform diagram of FIG. Generally, in order to make the control response faster, forcing is performed on the manipulated variable. Point A in FIG. 4 is a response when the terminal voltage command value VG is increased stepwise. The terminal voltage of both the generator and the exciter is almost proportional to the exciting current. The exciting current changes with respect to the exciting voltage depending on the time constant of the resistance and inductance of the field winding, and the time constant is usually very slow, on the order of several seconds. Therefore, in order to increase the terminal voltage VG1 of the generator quickly, forcing Vf1 to be larger than the final set value as shown in the figure to speed up the rise of if1. V
Forcing f1 requires further forcing Vf2 as shown in the figure. When the terminal voltage command value VG is increased, both Vf1 and Vf2 become positive voltages as shown in the figure. For forcing, the voltage ratings of the exciter and the automatic voltage regulator may be selected to be high.

By the way, the limit of the control response of the terminal voltage in the conventional method is when the terminal voltage is reduced. A point B in FIG. 4 is a response when the terminal voltage command value VG is decreased stepwise. Vf2 forcibly moves in the negative direction as shown in the figure in an attempt to rapidly decrease the terminal voltage VG1 of the generator. However, the lower limit of the exciting current if2 of the exciter is zero.
Even if the exciting current flows in the negative direction, the exciter is an AC machine, and the terminal voltage increases instead. Therefore, the minimum value of the excitation voltage Vf1 of the generator is also zero, and the excitation current if1 decreases slowly as shown by the time constant of the resistance and inductance of the field winding. If a negative forcing voltage is applied to the excitation voltage of the generator, fast control can be performed. However, in the conventional configuration, the response of the terminal voltage of the generator is slow because the lower limit is zero. As described above, the conventional brushless exciter has a limited response when the terminal voltage of the generator is reduced, and cannot be used for a generator that requires a fast terminal voltage control response.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brushless excitation device of a synchronous generator capable of performing a fast terminal voltage control response even when the terminal voltage of the synchronous generator is reduced. . [Structure of device]

[0010]

In order to achieve the above object, the present invention amplifies a terminal voltage command value of a synchronous generator and a difference between the terminal voltage and the first and second excitation voltage command value signals. An automatic exciter that is excited by an output based on the first excitation voltage command signal, an auxiliary exciter that is excited by an output based on the second excitation voltage command signal, A rotary rectifier that rectifies the output of the AC exciter and converts the output to DC, and a regenerative converter that converts the output of the auxiliary exciter to DC in a regenerative mode, wherein the rotary rectifier and the regenerative converter are connected in series. In the brushless exciter for a synchronous generator connected and configured to supply an exciting current to a field winding of the synchronous generator, when increasing the exciting current of the synchronous generator, the terminal voltage of the AC exciter is increased. Increased Performs positive forcing the synchronous generator excitation voltage through the rotating rectifier by Rukoto,
When decreasing the synchronous generator excitation current, the terminal voltage of the synchronous generator is controlled by increasing the terminal voltage of the auxiliary exciter and performing negative forcing on the synchronous generator excitation voltage through a regenerative converter. It is characterized by the following.

[0011]

According to the present invention, a negative forcing voltage can be applied to the field winding of the generator, and the response of the terminal voltage control can be improved.
In particular, the response when the terminal voltage is reduced can be increased. This makes it possible to supply an exciting current without using a brush without using a brush even in an application requiring a fast response, which cannot be handled by a conventional brushless exciter, thereby expanding the application of the generator.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a block diagram showing an embodiment of the present invention. The same components as those in FIG. 3 are denoted by the same reference numerals.

In FIG. 1, 1 is a generator, 1a is an armature winding of the generator, 1b is a field winding of the generator, 2 is an exciter,
2a is the armature winding of the exciter, 2b is the field winding of the exciter,
3 is a rotary rectifier, 4 is a voltage detector, 5 is a terminal voltage setter, 6a is an automatic voltage regulator, 6b is a power amplifier, 6c is a power amplifier, 7 is a bus, 8 is an auxiliary exciter, and 8a is an auxiliary exciter. , 8b is a field winding of the auxiliary exciter, 9 is a regenerative converter, 9a is a main circuit of the regenerative converter, and 9b is a firing circuit of the regenerative converter. VG is the terminal voltage command value of the generator 1, VG1 is the terminal voltage effective value of the generator 1, Vf1 is the excitation voltage of the generator 1, if1 is the excitation current of the generator 1, and Vf2 is the excitation voltage of the exciter 2. , If2 is the exciting current of the exciter 2, V1
Is the output voltage of the rotary rectifier 3, V2 is the output voltage of the regenerative converter 9, Vf3 is the excitation voltage of the auxiliary exciter 8, and if3 is the excitation current of the auxiliary exciter 8.

The operation of this embodiment will be described below with reference to FIG. During normal operation and when increasing the terminal voltage of the generator 1, the same operation as the conventional brushless exciter of FIG. 3 is performed. That is, the exciter 2 is excited by the power amplifier 6b, and the power generated by the exciter 2 is
And the generator 1 is operated. At this time, the auxiliary exciter 8 does not generate a voltage, and the regenerative converter 9 has an output voltage of zero. When the terminal voltage of the generator 1 is rapidly reduced, the auxiliary exciter 8 generates the terminal voltage by the exciting current if3 provided by the power amplifier 6c. Regenerative converter 9
With this terminal voltage as a power supply, the main circuit 9a is operated in the regenerative mode by the ignition circuit 9b, and the negative voltage V2
Generate. Forcing is performed using the negative voltage V2, and the exciting current if1 of the generator 1 can be reduced quickly. By arranging the auxiliary exciter 8 and the regenerative converter 9 on the same rotor as the regenerative rectifier 3 and the like, a contact portion such as a brush can be eliminated. Since the magnitude of V2 can be adjusted by the auxiliary exciting current if3, the firing phase by the firing circuit 9b may be a fixed phase that generates the maximum negative voltage. Therefore, there is no need to transmit a control signal or the like from the stator side to the rotor side, and maintenance-free operation can be realized. Further, the auxiliary exciter 8 and the regenerative converter 9 operate only for a short time when the terminal voltage of the generator 1 is reduced, and may be small in rating.

The operation of improving the response of the generator terminal voltage control according to the present invention will be described in more detail with reference to the operation waveform diagram of FIG. In the steady state and the point A in FIG. 2, the same operation as the conventional brushless exciter is performed as described above.
On the other hand, when decreasing the terminal voltage command value VG at the point B in a stepwise manner, Vf2 is forced in the negative direction as shown in the figure in an attempt to decrease the terminal voltage VG of the generator quickly. The exciting current if2 of the exciter 2 becomes zero, and the rotating rectifier 3
When the output voltage V1 becomes zero, the automatic voltage regulator 6a gives a command to the power amplifier 6c to increase the voltage. The excitation current if3 flows through the auxiliary exciter 8, and the terminal voltage is increased. Since the regenerative converter 9 is controlled to always operate in the regenerative mode, a negative voltage V2 is generated at its output. Due to this negative voltage, the exciting current of the generator 1 decreases rapidly, and the terminal voltage also decreases rapidly, so that the control response becomes faster.

Although the embodiment of FIG. 1 shows an example of a three-phase auxiliary exciter and a three-phase bridge regenerative converter, the present invention is not limited to this. A chopper circuit may be used, and even when applied to a single phase, the same operation as in the above-described embodiment is achieved.

[0017]

As described above, according to the present invention, even in the case of performing control to reduce the terminal voltage of the generator in the brushless exciter of the generator, a negative voltage forcing is applied to the generator field winding. By providing the sing, the generator exciting current can be reduced quickly, and the response of the generator terminal voltage control can be made faster. In addition, since the brushless structure is maintenance-free and the control signal is not transmitted between the stator and the rotor, the configuration is very simple. As a result, the brushless excitation device of the present invention can be applied to a system stabilizing device or the like that requires a very high-speed response, and has an excellent effect of saving labor and maintenance.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a generator and a brushless exciter showing one embodiment of the present invention.

FIG. 2 is a waveform diagram of each part for explaining the operation of the brushless excitation device of the present invention.

FIG. 3 is a configuration diagram of a conventional brushless excitation device of a generator.

FIG. 4 is a waveform diagram of each part for explaining the operation of the conventional brushless excitation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Generator, 2 ... Exciter, 3 ... Rotary rectifier, 4 ... Voltage detector, 5 ... Terminal voltage setting device, 6a ... Automatic voltage regulator, 6
b, 6c: power amplifier, 8: auxiliary exciter, 9: regenerative converter.

Claims (1)

(57) [Scope of request for utility model registration] An automatic voltage regulator for amplifying a difference between a terminal voltage command value of a synchronous generator and a terminal voltage thereof to obtain first and second excitation voltage command value signals, and said first excitation voltage command signal , An auxiliary exciter that is excited by an output based on the second excitation voltage command signal, and a rotary rectifier that rectifies the output of the AC exciter and converts the output to DC. And a regenerative converter for converting the output of the auxiliary exciter to DC in a regenerative mode, wherein the rotary rectifier and the regenerative converter are connected in series to supply an exciting current to a field winding of the synchronous generator. In the brushless excitation device for a synchronous generator configured to supply, when increasing the exciting current of the synchronous generator, the terminal voltage of the AC exciter is increased to increase the synchronous generator excitation through the rotary rectifier. Do a positive forcing on the voltage,
When decreasing the synchronous generator excitation current, the terminal voltage of the synchronous generator is controlled by increasing the terminal voltage of the auxiliary exciter and performing negative forcing on the synchronous generator excitation voltage through a regenerative converter. A brushless exciter for a synchronous generator.