JP6699896B2 - Brushless excitation system, brushless excitation method, brushless excitation program and synchronous generator - Google Patents

Description

  Embodiments of the present invention relate to a brushless excitation technique for controlling a generator field of a rotating field type synchronous generator.

In a rotating field type synchronous generator, a direct current is passed from an excitation system to a generator field circuit, so that the generator field becomes an electromagnet.
This generator field excitation method includes a thyristor excitation method that requires a brush that collects electricity and a sliding contact body such as a slip ring that electrically connects the brush to the rotating shaft of the generator field. It is roughly classified into a brushless excitation method that does not require a dynamic contact body.
The brushless excitation synchronous generator does not require a sliding contact body and therefore does not require brush replacement or frequent maintenance, and is actively used in Europe and elsewhere.

The brushless excitation system mainly includes an AC exciter that excites the generator field and a permanent magnet generator (PMG: Permanent Magnet Generator) that excites the AC exciter.
An AC current is generated in the AC exciter armature as the AC exciter armature rotates in the static magnetic field generated by the PMG in the surrounding space of the AC exciter field.
This alternating current is rectified into a direct current by a rotary rectifier provided on the rotating shaft, and then circulates in a generator field circuit to excite the generator field.

In a brushless excitation system, the output current amount to the generator field circuit is controlled by increasing or decreasing the amount of current flowing from the PMG armature circuit to the AC exciter field circuit, and the excitation of the generator field is controlled. You can
Normally, the amount of power generation is kept constant by an automatic voltage regulator (AVR) that monitors the generator output voltage and automatically adjusts the output of the PMG.
In the event of a power system accident, for example, when the generator output voltage suddenly drops due to a lightning strike or the like, the AVR controls the output of the PMG and applies a field voltage higher than the generator rated field voltage (hereinafter referred to as forcing By doing so, the generator output voltage is increased in a short time.

Japanese Utility Model Laid-Open No. 4-118800 JP-A-11-27995

However, if the duration of the accident is long and, for example, the recovery of the generator output voltage takes a long time, the conventional control method causes a delay in the control until the generator output voltage is recovered, and the generator during forcing is therefore delayed. A voltage above the maximum field voltage is applied to the generator field circuit.
As a result, in the conventional brushless excitation system, an overvoltage is applied to the components in the excitation system, which may exceed the voltage allowable value of the device of the device and damage these devices.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a brushless excitation system, a brushless excitation method, a brushless excitation program, and a synchronous generator that prevent damage to elements in the brushless excitation system due to overvoltage. And

  The brushless excitation system according to the present embodiment is installed in a generator excitation circuit, and a state detection unit that detects the generator field quantities, and an ignition signal based on the detected generator field quantities. An ignition signal modulating unit for modulating and a rotary rectifier including an element in which the ignition signal modulating unit is connected to a gate terminal are provided.

  The brushless excitation method according to the present embodiment is a step of causing a state detection unit installed in a generator excitation circuit to detect generator field quantities, and an ignition signal based on the detected generator field quantities. And modulating the amount of current flowing through the generator excitation circuit based on the modulated ignition signal.

The brushless excitation program according to the present embodiment, the computer, the step of causing the state detection unit installed in the generator excitation circuit to detect the generator field various amounts, the step of modulating the ignition signal based on the modulation command signal The step of changing the amount of current flowing through the generator excitation circuit based on the modulated ignition signal is executed.

  The present invention provides a brushless excitation system, a brushless excitation method, a brushless excitation program, and a synchronous generator that prevent damage to elements in the brushless excitation system due to overvoltage.

The figure which shows the basic structure of the brushless excitation type synchronous generator. 1 is a schematic circuit diagram of a synchronous generator including an excitation system according to a first embodiment. (A) is a diagram showing an example in which a voltmeter is used as a state detection unit, (B) is a diagram showing an example in which an ammeter is used as a state detection unit, and (C) is a diagram in which a voltmeter is used as a state detection unit The figure which shows an example. The logic circuit diagram which shows an example of a firing signal modulation part. The timing chart of the output signal in the logic circuit of the ignition signal modulator. The schematic circuit diagram of the excitation system concerning a 2nd embodiment. 3 is a flowchart showing a brushless excitation method according to the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
First, the basic structure of the brushless excitation synchronous generator 10 will be described with reference to FIG.
FIG. 1 is a schematic configuration diagram of a synchronous generator 10 including a brushless excitation system 30 (hereinafter, simply referred to as “excitation system 30”) according to the first embodiment.

  In a rotating field type synchronous generator 10, as shown in FIG. 1, a rotating shaft 13 is provided with a generator field 11, an AC exciter armature 14, and a permanent magnet field 19 (PMG field 19). .

An automatic voltage regulator 29 (AVR 29) is connected to the power output system 28 of the synchronous generator 10 connected to the generator armature 27.
The AVR 29 adjusts the input voltage value from the permanent magnet generator 17 (PMG 17) to the AC exciter field 18 in accordance with the output voltage of the generator armature 27 (hereinafter referred to as “generator output voltage”).
The adjustment by the AVR 29 stabilizes the generator output voltage at the set rated output value.

Specifically, the AVR 29 is on the path connecting the PMG armature 22 and the AC excitation magnetic field magnet 18 when the generator output voltage transformed by the transformer 32 so as to be monitored is smaller than the set rated output value. Of the PMG ignition signal transmitted to the rectifier 24 of FIG.
The modulation of the PMG ignition signal increases the DC current flowing through the generator field circuit 16 of the PMG 17.
On the contrary, when the generator output voltage is small, the direct current is reduced in the same manner.

FIG. 2 is a schematic circuit diagram of the synchronous generator 10 including the excitation system 30 according to the first embodiment.
As described above, various control delay elements such as AVR29, PMG17, AC exciter 15, electromagnetic induction of the generator, etc. are set between the forcing of the generator field voltage and the recovery of the generator output voltage. Therefore, the arrival of information is delayed with respect to each other, and it is not possible to perform highly responsive and accurate control.
Due to such a delay in transmission of information, an overvoltage may be applied to the generator field 11 circuit, and the elements of the excitation system 30 may be damaged.
Therefore, a measure is taken to control the direct current output from the rotary rectifier 26 for highly responsive control, and to prevent damage to the elements in the excitation system 30 due to overvoltage applied to the generator field 11. You will need it.

Therefore, as shown in FIG. 2, the excitation system 30 according to the first embodiment is installed in the generator field circuit 16 and is detected by the state detection unit 33 that detects various amounts of the generator field. An ignition signal modulator 47 that modulates the ignition signal S based on the generator field quantities.
The state detection unit 33 and the firing signal modulation unit 47 are connected via the modulation command unit 38.

Further, the rotary rectifier 26 is provided with an AC pure bridge circuit including a thyristor element 63a.
The ignition signal modulator 47 is connected to the gate of the thyristor element 63a to adjust the amount of current in the generator field circuit 16.

No current flows through the thyristor element 63a unless the firing signal S is input from the gate.
Therefore, during normal operation, the ignition signal modulator 47 always inputs the steady ignition signal S3 whose phase is adjusted so that the maximum current can be output, for example.
Since the anode (A) and the cathode (C) are steadily conducted by the steady ignition signal S3, the thyristor element 63a outputs a waveform similar to the rectified waveform by the diode.

The state detection unit 33 is provided in the generator field circuit 16 and detects various amounts of the generator field.
The generator field quantities are, for example, a current flowing into the generator field circuit 16 or a voltage applied thereto or a voltage applied to the element 63 to be protected.

Further, FIG. 3A is a diagram showing an example in which a voltmeter 34 is used as the state detection unit 33, FIG. 3B is a diagram showing an example in which an ammeter 35 is used as the state detection unit 33, and FIG. 8] is a diagram showing another example in which a voltmeter 34 is used for the state detection unit 33.
3A to 3C, the threshold value holding unit 37 and the modulation command unit 38 are not shown.

The state detection unit 33 is, for example, a voltmeter 34 or an ammeter 35 including a shunt resistor 36, as shown in FIGS. 3(A) and 3(B).
Hereinafter, the generator field amounts will be described as the generator field voltage V except for the example of FIG.
For example, in the case of the voltmeter 34, a shunt resistor 36 having a low resistance of several tens mΩ to several hundreds mΩ is inserted in series in the circuit to detect a voltage drop in the shunt resistor 36.
The state detection unit 33 may use a Hall element or a current transformer instead of the shunt resistor 36.

Further, as shown in FIG. 3C, even if the voltmeter 34 is connected to both ends of the generator field 11 without using the shunt resistor 36, the generator field voltage V is directly measured. Good.
By directly measuring the generator field voltage V at both ends of the generator field 11, the generator field voltage V can be measured with high accuracy.
With respect to this generator field voltage V, a plurality of thresholds serving as a reference for modulating the ignition signal S are set and held in the threshold holding unit 37.

Information on the generator field voltage V detected by the state detection unit 33 is transmitted to the modulation command unit 38.
When the generator field voltage V exceeds the threshold value held in the threshold value holding unit 37, the modulation commanding unit 38 sends a modulation command signal σ according to the exceeded threshold value to the ignition signal modulating unit 47.
For example, when the threshold value close to the set allowable value as the device is exceeded, the voltage value of each phase is set to a negative value and the modulation command signal σ that induces negative forcing is transmitted.

Note that the modulation command signal σ transmitted by the modulation command unit 38 is not limited to the one that changes based on the type of the exceeded threshold value.
For example, the modulation command signal σ may be changed based on the magnitude or speed of the rise or fall of the generator field voltage V.

The ignition signal modulator 47 modulates the ignition signal S based on the modulation command signal σ.
Here, FIG. 4 is a logic circuit diagram showing an example of the ignition signal modulator 47.
As shown in FIG. 4, for example, the ignition signal modulator 47 includes a stationary pulse transmitter 51 (in the figure, a stationary ignition signal transmitter 51) that constantly transmits a stationary ignition signal S1 and a modulation commander 38. The temporary pulse transmission section 52 (temporary arc signal transmission section 52 in the figure) placed on the input modulation command signal σ and the steady firing signal S3 is switched to the modulation firing signal S4 when the modulation command signal σ is received. And a switching unit 53.

The steady pulse transmitter 51 is provided with a steady switch 54a, and the temporary pulse transmitter 52 is provided with a temporary switch 54b.
Further, a switching unit 53 is connected to the stationary pulse transmission unit 51 and the temporary pulse transmission unit 52.
Then, the switching unit 53 is connected to the steady switch 54a and the temporary switch 54b.
The switching unit 53 includes, for example, a steady step signal transmission unit 57a connected to the steady pulse transmission unit 51 and a temporary step signal transmission unit 57b connected to the temporary pulse transmission unit 52.

The steady step signal transmitter 57a and the temporary step signal transmitter 57b are connected to the NAND circuit 58.
The output terminal of the NAND circuit 58 is branched, and one is connected to the steady switch side AND circuit 61a and the other is connected to the temporary switch side AND circuit 61b via the NOT circuit 62.
The steady switch side AND circuit 61a is connected to the steady switch 54a, and the temporary switch side AND circuit 61b is connected to the temporary switch 54b.

  Here, FIG. 5 is a timing chart of the output signal in the logic circuit of the ignition signal modulator 47.

  The various signals include a steady firing signal S1, a steady step signal M1, a step signal output from the steady switch side AND circuit 61a (that is, ON/OFF of the steady switch 54a), a steady firing signal S3 output to the gate, The modulation firing signal S2, the modulation step signal M2, the step signal output from the temporary switch side AND circuit 61b (that is, ON/OFF of the temporary switch 54b), and the modulation firing signal S4 output to the gate.

The pulse of the steady firing signal S1 constantly transmitted from the steady pulse transmission unit 51 is input to the steady step signal transmission unit 57a to emit the steady step signal M1 which is always ON.
The temporary pulse transmission unit 52 transmits the modulation firing signal S2 to the temporary step signal transmission unit 57b based on the modulation command signal σ received from the modulation instruction unit 38, so that the temporary step signal transmission unit 57b causes the temporary step signal M2. To send.

During normal times when only the steady step signal M1 is transmitted, a step signal is output from the steady switch side AND circuit 61a to turn on the steady switch 54a.
When the steady switch 54a is ON, the steady signal modulator 47 outputs a steady firing signal S3.

On the other hand, when the modulation step signal M2 is transmitted, a step signal is output from the temporary switch side AND circuit 61b, and the temporary switch 54b is turned on.
When the temporary switch 54b is ON, the ignition signal modulator 47 outputs the modulated ignition signal S4.
At this time, the step signal from the temporary switch side AND circuit 61b is stopped, and the steady switch 54a is turned off.

That is, by such a switching unit 53, the modulated ignition signal S4 is transmitted without being mixed with the steady ignition signal S3.
That is, it is possible to prevent the ignition failure due to the mixture of the ignition signals S (S3, S4).
4 and 5 show an example of the ignition signal modulator 47, which may be of a digital type or an analog type.

By the way, in the multi-phase AC pure bridge rotary rectifier configured by the thyristor element 63a, the voltage value applied to the element 63 is made negative by shifting the phase of the current value and the voltage value depending on the combination with other elements. You can also do it.
By making the voltage value negative, the current value does not take a negative value, but this current value can be quickly reduced and quickly stabilized at a desired current value.

With the above configuration, the generator field voltage V is monitored and fed back separately from the control by the AVR 29, so that the damage of the device due to the overvoltage can be prevented.
Further, by providing the rotating shaft 13 with all of such a configuration, contact between the rotating body and the stationary body such as the AVR 29 for exchanging information regarding the generator field voltage V becomes unnecessary.

  Next, the brushless excitation method according to the first embodiment will be described using the flowchart of FIG. 7 (see FIGS. 1 and 2 as appropriate).

First, the modulation command unit 38 monitors the generator field voltage V detected by the state detection unit 33 installed in the generator field circuit 16 (S11).
The detection may be performed all the time or may be triggered by a sudden change in the voltage inside the generator field circuit 16 or the like.
The modulation command unit 38 refers to the threshold value holding unit 37, for example, and compares the generator field voltage V with each threshold value for monitoring.

When the ignition signal modulator 47 transmits the steady ignition signal S1, the thyristor element 63a functions as a diode (S12).
If the detected generator field amounts do not exceed any of the threshold values, the monitoring is continued (S13:NO:S11).

On the other hand, when the detected generator field amounts exceed the upper limit threshold value, the modulation command unit 38 transmits the modulation command signal σ of the down command (S13:YES:S14).
When the threshold value is the lower limit threshold value, the modulation command unit 38 transmits the modulation command signal σ of the increase command when the threshold value is lower than the lower limit threshold value.
Then, the firing signal modulator 47 that has received the modulation command signal σ according to the threshold value modulates the firing signal S based on the modulation command signal σ (S15).
The modulated ignition signal S is input from the gate, and the thyristor element 63a changes the current flowing into the generator field 11 to adjust it to the optimum generator field voltage V (S16:END).

Note that such an operation may be executed by a computer according to a program.
For example, the modulation command unit 38, the firing signal modulation unit 47, and the state detection unit 33 include a processor such as a CPU, a ROM (Read Only Memory), a RAM (Random Access Memory), or a storage device such as an HDD (Hard Disk Drive). Can be configured as a computer including.

In this case, of the units shown in FIG. 2, the functions of the state detection unit 33, the modulation command unit 38, and the firing signal modulation unit 47 are realized by the processor executing a predetermined program stored in the storage device. You can
Further, instead of such software processing, it can be realized by hardware such as ASIC (Application Specific Integration Circuit) and FPGA (Field-Programmable Gate Array).

Furthermore, the state detection unit 33, the modulation command unit 38, the firing signal modulation unit 47, and the like can be realized by combining software processing and hardware processing.
Further, in the configuration shown in FIG. 2, the threshold value holding unit 37 is realized by a storage device such as a ROM or a RAM.

  As described above, according to the excitation system 30 of the first embodiment, the generator field voltage V is automatically controlled separately from the control by the AVR 29, so that damage to the device due to overvoltage can be prevented.

  Further, since the amount of current in the generator field circuit 16 can be adjusted by controlling the phase by the thyristor element 63a in the rotary rectifier 26, the desired generator field voltage V can be immediately stabilized. .

Further, in the excitation system 30, the state detection unit 33 that monitors and controls the generator field voltage V, the threshold value holding unit 37, the modulation command unit 38, and the ignition signal modulation unit 47 are all provided on the rotating body.
Therefore, it is possible to maintain the feature of the brushless excitation method that the rotating body and the stationary body such as the AVR 29 are not required to be a consumable item and the maintenance is easy.
That is, it is possible to maintain the characteristics of the brushless excitation method and prevent damage to the elements in the excitation system 30 due to overvoltage.

(Second embodiment)
FIG. 6 is a schematic circuit diagram of the excitation system 30 according to the second embodiment.

In the excitation system 30 according to the second embodiment, as shown in FIG. 6, the rotary rectifier 26 is a mixed bridge circuit of a thyristor element 63a and a diode element 63b.
In the first embodiment, an example of a three-phase pure bridge rotary rectifier using all the elements 63 as thyristor elements 63a is shown.

On the other hand, in the second embodiment, for example, the thyristor element 63a is arranged downstream of the output terminal of the AC exciter armature 14 and the diode element 63b is arranged upstream thereof.
Even in the case of such an arrangement, negative forcing can be applied by the phase control of the thyristor element 63a.

Since the thyristor element 63a needs an input from the gate in order to pass a current, the steady firing signal S1 from the modulator 47 is always required even in the steady state.
Since it is necessary to provide the modulator 47 with input terminals corresponding to the number of gates of the thyristor element 63a, the number of parts of the ignition signal modulator 47 increases and the configuration becomes complicated.
Therefore, it is preferable to use the diode element 63b in a portion that is not essential for phase control.

  As described above, according to the second embodiment, the configurations of the ignition signal modulator 47 and the rotary rectifier 26 can be simplified.

The second embodiment has the same structure and operation procedure as those of the first embodiment except that both the thyristor element 63a and the diode element 63b are used for the rotary rectifier 26, and thus the duplicate description will be omitted.
Also in the drawings, portions having the same configuration or function are denoted by the same reference numerals, and overlapping description will be omitted.

  As described above, according to the excitation system 30 of the second embodiment, in addition to the effects of the first embodiment, the configurations of the ignition signal modulation unit 47 and the rotary rectifier 26 can be simplified, and thus the risk of failure is obtained. Can be reduced.

According to the excitation system 30 of at least one embodiment described above, damage to the device due to overvoltage can be prevented by automatically controlling the generator field voltage V separately from the control by the AVR 29.
In addition, since the negative forcing can be applied by controlling the phase of the thyristor element 63a in the rotary rectifier 26, it is possible to immediately stabilize the desired generator field voltage V.

Further, in the excitation system 30, since the rotating body and the stationary body such as AVR are connected to each other and the consumable brush is not necessary, the maintenance management is facilitated.
That is, it is possible to maintain the characteristics of the brushless excitation method and prevent damage to the elements in the excitation system 30 due to overvoltage.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention.
These embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the spirit of the invention.
The embodiments and their modifications are included in the scope of the invention and the scope thereof, and are included in the invention described in the claims and the scope of equivalents thereof.

  DESCRIPTION OF SYMBOLS 10... Brushless excitation type synchronous generator, 11... Generator field, 13... Rotating shaft, 14... AC exciter armature, 15... AC exciter, 16... Generator field circuit, 17... Permanent magnet generator (PMG), 18... AC exciter field, 19... Permanent magnet field (PMG field), 22... PMG armature, 24... Rectifier, 26... Rotary rectifier, 27... Generator armature, 28... Power output System, 29... Automatic voltage regulator, 30... Brushless excitation system (excitation system), 32... Transformer, 33... State detection unit, 34... Voltmeter, 35... Ammeter, 36... Shunt resistor, 37... Threshold holding Part, 38... Modulation command part, 47... Ignition signal modulation part, 51... Steady pulse transmission part (steady ignition signal transmission part), 52... Temporary pulse transmission part (temporary arc signal transmission part), 53... Switching part , 54a... Steady switch, 54b... Temporary switch, 57a... Steady step signal transmitter, 57b... Temporary step signal transmitter, 58... NAND circuit, 61a... Steady switch side AND circuit, 61b... Temporary switch side AND circuit, 62... NOT circuit, 63 (63a, 63b)... Element (thyristor element, diode element), M1... Steady step signal, M2... Modulation step signal, S... Firing signal, S1... Steady firing signal, S2... Modulation firing signal , S3... Steady ignition signal, S4... Modulation ignition signal, V... Generator field voltage, σ... Modulation command signal.

Claims (7)

A state detection unit that is installed in the generator excitation circuit and detects the generator field amounts,
An ignition signal modulator that modulates an ignition signal based on the detected generator field amounts,
A rotary rectifier including the element in which the ignition signal modulator is connected to a gate terminal, and a brushless excitation system. The brushless excitation system according to claim 1, further comprising a modulation command unit that transmits a modulation command signal to the ignition signal modulation unit when the detected generator field amounts exceed a predetermined threshold value. The brushless excitation system according to claim 1 or 2, wherein the element is a thyristor element. The brushless excitation system according to claim 3, wherein the rotary rectifier is a circuit including the thyristor element and the diode element. A synchronous generator comprising the brushless excitation system according to any one of claims 1 to 4. A step of causing the state detection section installed in the generator excitation circuit to detect the generator field amounts,
Modulating a firing signal based on the detected generator field quantities;
Changing the amount of current flowing through the generator exciting circuit based on the modulated ignition signal. On the computer,
A step of causing the state detection unit installed in the generator excitation circuit to detect the generator field amounts,
Modulating the firing signal based on the modulation command signal,
And a step of changing the amount of current flowing through the generator exciting circuit based on the modulated ignition signal.

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