JP3055297B2 - Rapid response excitation device for brushless generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic voltage control device for a so-called brushless excitation type generator (also referred to simply as a brushless generator) as a generator with an exciter used for a thermal, hydraulic or nuclear power plant. The present invention relates to a quick response excitation device for increasing control speed and improving system stability.

[0002] In the drawings, the same reference numerals indicate the same or corresponding parts.

[0003]

2. Description of the Related Art Conventionally, as an excitation system for a brushless generator of this type, a system having the configuration shown in FIG. 7 is known. In the figure, 1 is a generator, 1a is a field winding of the generator 1, If is a generator field current flowing through the field winding 1a, 7 is an exciter directly connected to the axis of the generator 1. , D1 are diodes that rectify the AC generated voltage of the exciter 7 and output a field current If.

[0004] Next 7a field winding of the exciter 7, 4 excitation power supply of alternating current for energizing the field winding 7a, V _AC voltage of the excitation power supply, 6 is the excitation power supply 4 thyristor providing a variable field voltage in series with the field winding 7a of exciter 7 a voltage V _AC controlled rectifier to, alpha phase angle control signal for varying the firing phase angle of the thyristor 6, 5 Is an exciter exciting current detector for detecting an exciter exciting current flowing to the exciter field winding 7a through the thyristor 6, and Ie is a value of the exciter exciting current detected by the detector 5.

Next, 8 is a system to which the power generated by the generator 1 is supplied, 2 is a generator voltage detector for detecting the voltage generated by the generator 1, V is the generator voltage detected by the detector 2, Reference numeral 3 denotes an automatic voltage regulator (AV) which receives the exciter exciting current Ie and the generator voltage V and supplies a phase angle control signal α to the thyristor 6 so that the voltage value V maintains a predetermined value.
R).

FIG. 8 shows an example of a circuit configuration of the automatic voltage regulator 3 of FIG. In the figure, Vs is the set value of the generator voltage, 9 is this voltage set value Vs and the voltage detector 2
Enter the difference ΔV between the detected generator voltage V via the by PI adjuster for adjusting outputting a command value V _A of the exciting current to the difference between 0 and 10 the current command value V _A The limiter 11 for limiting receives the difference between the exciting current command value _VA and the exciting machine exciting current Ie detected via the exciting machine exciting current detector 5 so that the difference becomes zero. A PI controller for providing a phase angle control signal α to the thyristor 6;
Is a limiter for limiting the value of the phase angle control signal α.

In the configuration of the brushless excitation system shown in FIG. 7, the generator 1 is provided with a slip ring and a brush, and the generator field winding 1a is directly excited by an excitation power supply 4 and a thyristor 6 to directly excite the thyristor. Compared to the method,
The maintenance of the brush is not required, but there is a control delay corresponding to the delay of the exciter 7. To improve this, the exciting current Ie of the exciter is fed back as shown in FIG. 8 to reduce the equivalent delay time.

FIG. 9 is a block diagram of an exciter current control system as a minor loop in the automatic voltage regulator 3 of FIG. Here, K is a proportional gain of the control system, Te is a delay time of the exciter, and s is a Laplace operator. FIG. 10 shows an equivalent block when a control system is configured by the proportional gain K and the feedback loop as shown by the dotted line in FIG. As shown in the figure, the exciter delay time Te is equivalently Te × (1 / (K + 1)) by providing this current control system. Therefore, if K> 1 is selected, the equivalent delay time can be shortened.

[0009]

[SUMMARY OF THE INVENTION While, as described above conventionally using methods to accelerate the delay equivalent to the exciter by the feedback control of the exciter excitation current, in this case, the voltage V _AC of the excitation power supply 4 Short-time rated maximum exciter exciting current Iec determined by mechanical system conditions when control system output is maximum
Is designed to flow. By the way, shortening the excitation delay time is extremely important for improving the stability of the system at present, as the power supply margin is decreasing. In order to further shorten the delay time, the capacity of the exciter is increased and the maximum allowable exciter exciting current Iec for a short time is increased.
May be increased, or a time constant may be shortened by inserting a resistor in series with the excitation circuit. However, the former is disadvantageous in that it increases the size of the exciter, increases the cost, and the like, and the latter is disadvantageous in that it causes an increase in the loss and is not an ideal solution.

Accordingly, an object of the present invention is to provide a brushless generator quick response excitation device which can solve the above problem and further reduce the exciter delay of the brushless excitation method and realize quick response control. .

[0011] In order to solve the above-mentioned problem, a fast-acting excitation device according to claim 1 includes a generator (1) and a diode (D1).
Exciter that excites brushlessly (such as through 7)
Control rectifies the voltage of the excitation power supply (4, etc.) and applies a DC variable field corresponding to a rectification control signal (phase angle control signal α, etc.) to a field winding (7a, etc.) of the exciter (7, etc.). A control rectifier (such as a thyristor 6) for providing a magnetic voltage and a current command value are adjusted so that the voltage generated by the generator (such as 1) (detected via the detector 2 or the like) becomes equal to a voltage set value. An output voltage adjusting means (such as a PI controller 9) and an exciter exciting current supplied to a field winding of the exciter (such as 7) via the control rectifying means (such as 6) correspond to the current command value. In a brushless generator provided with current adjusting means (such as a PI adjuster 11) for adjusting and outputting the rectification control signal so as to be equal, the voltage of the exciting power supply (such as 4) is allowed for a short time of the exciting current of the exciting machine. Maximum value (short-time allowable maximum exciter exciting current Iec Current) (such as Iec1)
Overcurrent determination means (comparator 13, flip-flop 15, etc.) for determining that the exciting current has exceeded the short-time allowable maximum value, and a determination by the overcurrent determination means. Excitation current limiting means for limiting the field voltage output from the control rectifier to a voltage (Vec or the like) at which the exciter exciting current of the shortest allowable maximum value flows. Exciter for brushless generator.

According to a second aspect of the present invention, the exciting current limiting means limits the current command value output by the voltage adjusting means (limit value setting). The field voltage is limited as described above via the circuit 16 and the limiter circuit 10). According to a third aspect of the present invention, the exciting current limiting means directly limits the rectification control signal output by the current adjusting means (limit value setting). The circuit 17 limits the field voltage as described above via the circuit 17 and the limiter circuit 12).

According to a fourth aspect of the present invention, the exciting current limiting means is replaced by the control rectifying means instead of the current adjusting means. As described above, the field current is limited through means for providing a control signal (function generator 18, changeover switch 19, etc.).

[0014]

The short-time allowable maximum exciter exciting current Iec is (Ie
c) Since it is determined by the heat generation of ² × (time t), it is not an absolute condition to keep the exciter exciting current Ie below the maximum value Iec, but there is some time margin. Focusing here, taking advantage of the feedback control of conventional exciter excitation current, in addition several times than the value required to provide the short period of time allowed maximum exciter excitation current Iec of exciter excitation supply voltage V _AC is high By designing, the rise time of the excitation current Ie when the output of the control system is maximum is shortened, and the equivalent delay time of the exciter is reduced as much as possible to realize the quick response control. However, although the excitation power supply voltage _VAC was increased, the capacity of the exciter was not changed, so the maximum limiting current was Iec. Therefore, if Ie> Iec, Ie =
A protection circuit to be used as Iec is newly provided.

According to the first to third aspects of the present invention, when the exciting current Ie for the exciter exceeds the allowable maximum value Iec for a short time, the outputs of the PI controllers 9 and 11 of the voltage control system or the current control system are changed. By limiting, the current is kept within the allowable value Iec. As another protection method, in the invention according to claims 1 and 4, Ie is Iec.
Is exceeded, the phase angle control signal α to the thyristor 6 is switched to the output signal of the function generator 18 different from the output of the AVR 3 via the changeover switch 19, so that the exciting current Ie of the exciter is suppressed to within an allowable value.

However, when the exciter exciting current Ie becomes less than the continuous maximum allowable current Iem of the exciter, the limit values of the PI adjusters 9 and 11 become the original values, and the function generator 1
The function of returning the output of 8 to the output of AVR3 is provided.
In order to realize the above functions, Ie> Iec, Ie <
Comparators 13 and 14 for judging Iem, flip-flop operation unit 15, limit value setting circuits 16 and 17, function generator 18 for controlling thyristor firing angle, changeover switch 19 operated by output signal of flip-flop 15, etc. Is provided.

In this way, designing the excitation power supply voltage to be high has the same effect as increasing the capacity of the exciter in the range of Ie <Iec, and the delay time of the exciter can be shortened. Quick response control can be realized. When Ie> Iec, the protection circuit operates, so that the winding does not suffer damage due to heating.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a fast response excitation apparatus according to the present invention; FIG.

The details will be described below. In the present invention

Have designed a voltage V _AC of the excitation power supply 4 as described above to a higher value that can flow several times the value Iec1 brief allowable maximum exciter excitation current Iec in [action]. However, the capacity of the exciter is not changed. For this reason, when the exciting machine exciting current Ie becomes equal to or more than the maximum value Iec, the exciting current Ie is limited to avoid overheating of the exciting machine field winding.

FIG. 1 shows a first embodiment of the present invention.
(Relation 2) shows the configuration of the automatic voltage regulator 3 including the exciting current limiting means, and this figure corresponds to FIG. That is, in FIG. 1, the output of the PI controller 9 of the voltage control system is limited in order to limit the exciting machine exciting current Ie. As means for this limit, a comparator 13 for determining (exciter exciting current Ie)> (short-time allowable maximum exciting motor exciting current Iec), (exciter exciting current Ie) <(continuous allowable maximum exciting machine excitation) A current Iem), a flip-flop 15 which is set by the output of the comparator 13 and is reset by the output of the comparator 14, and a limit value setting circuit 16. The limit value setting circuit 16 sets a limit value for the limiter circuit 10 so that when the output of the flip-flop 15 is set, the current command value _VA output from the PI controller 9 is set to a maximum allowable value for a short time. Exciter exciting current I
ec. As a result, the phase angle control signal α becomes the excitation voltage (field voltage) V at which the excitation current limit value Iec flows.
thyristor 6 in which ec is applied to exciter field winding 7a
Is limited to the value that gives the firing angle of

The limit value setting circuit 16 similarly sets a limit value for the limiter circuit 10 so that when the flip-flop 15 is reset, the PI
The limit value of the output of the controller 9 is returned to the original limit value. FIG. 2 shows a second embodiment of the present invention (related to claims 1 and 3).
1 shows a configuration of an automatic voltage regulator 3 including an exciting current limiting means. FIG. 2 is configured to limit the output of the PI controller 11 of the current control system. That is,
The limit value setting circuit 17 sets a limit value for the limiter circuit 12 so that the flip-flop 15
Is set, the output of the PI controller 11 is limited to the phase angle control signal α that gives the thyristor firing angle such that the exciting machine field voltage Vec through which the exciting current limiting value Iec flows, and the flip-flop 15 is similarly reset. Sometimes regulator 11
The output limit value is returned to the original limit value.

FIG. 3 shows a configuration of an automatic voltage regulator 3 including exciting current limiting means according to a third embodiment of the present invention. In FIG. 3, for the same purpose, the outputs of the PI adjusters 9 and 11 are limited via limit value setting circuits 16 and 17, respectively. FIG. 4 shows the configuration of the exciting current limiting means as a fourth embodiment (related to claims 1 and 4) of the present invention. FIG. 4 shows that when (exciter exciting current Ie)> (short-time allowable maximum exciting machine exciting current Iec), the output source of the phase angle control signal α to be applied to the thyristor 6 is disconnected from the output of the controller 11 and determined in advance. The case where the output is switched to the output of the function generator 18 that generates a given function is shown. FIG. 5 is a time chart showing characteristics of functions generated by the function generator 18 of FIG.

In FIG. 4, the output of the comparator 13 and the PI adjuster 11 for judging Ie> Iec as switching means of the output source of the phase angle control signal α is the excitation voltage (field) corresponding to the continuous allowable maximum exciter excitation current Iem. A comparator 14A for determining that the voltage has become smaller than (magnetic voltage) Vem, a flip-flop 15 for resetting by the output of the comparator 13 and resetting by an output of the comparator 14A, and a changeover switch 19.

The changeover switch 19 supplies the phase angle control signal α to the thyristor 6 from the function generator 18 by the output when the flip-flop 15 is set, and also outputs the PI controller 11 by the output when the flip-flop 15 is reset. Switch to give from. The output signal of the function generator 18 (in this case, a time chart of the excitation voltage (field voltage) corresponding to the phase angle control signal α for convenience) is, as shown in FIG. The excitation voltage Vec corresponding to the machine excitation current Iec falls to the excitation voltage Vem corresponding to the continuously allowable maximum exciter machine excitation current Iem in T0 time, and thereafter the excitation voltage Vem is maintained.

[0025]

Having designed several times higher than the voltage Vec necessary to supply a short time allowable maximum exciter excitation current Iec According to the present invention the voltage V _AC of the excitation source 4 to the exciter according to the present invention,
When the output of the control system is maximum, there is an effect equivalent to increasing the capacity of the exciter several times, the rise time of the exciter exciting current Ie is shortened, and the equivalent time constant of the exciter delay can be shortened. .

When (exciter excitation current Ie)> (short-time allowable maximum excitation motor excitation current Iec) due to the rise of the excitation current Ie, a protection circuit is provided to limit the excitation voltage of the excitation motor field winding. Therefore, the overcurrent does not damage the exciter field winding. Then, the effect of the operating characteristics of the exciter exciting current according to the present invention will be described with reference to FIG.

FIG. 6 shows the relationship between the excitation voltage and the excitation current of the exciter at the time of maximum excitation. That is, in the conventional type, the excitation voltage is the maximum Vec as shown by the characteristic of the dashed line in FIG.
Is a time constant t ₂ . On the other hand, according to the present invention, since the maximum value of the excitation voltage is Vec1, the maximum value of the excitation current is Iec1, and as is apparent from FIG.
The time to reach ec is t ₁ . In this case, since (t ₁ / t ₂ ) = (Iec / Iec 1) = (Vec / Vec ₁ ) holds, the relationship between t ₁ and t ₂ is t ₁ = (Vec / Vec ₁ ) × t ₂ .

For example, if Vec1 is selected to be three times Vec, t ₁ = ( _１ ／) × t ₂ , that is, the exciter delay time t
₂ can be reduced to 1/3, and quick response can be realized. On the other hand, if the exciting current reaches Iec, Vec1 is switched to Vec by the signal of the flip-flop and Iec
Does not grow any further, so that overheating damage of the windings can be avoided.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the spirit of the present invention. Of course.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an automatic voltage regulator including an exciting current limiting unit according to a first embodiment of the present invention;

FIG. 2 is a configuration diagram of an automatic voltage regulator including exciting current limiting means as a second embodiment of the present invention.

FIG. 3 is a configuration diagram of an automatic voltage regulator including exciting current limiting means as a third embodiment of the present invention.

FIG. 4 is a configuration diagram of an exciting current limiting unit as a fourth embodiment of the present invention.

FIG. 5 is a time chart showing output characteristics of the function generator of FIG. 4;

FIG. 6 is a time chart showing transitions of the excitation voltage and the excitation current when the excitation voltage is maximally increased to explain the effect of the present invention.

FIG. 7 is a diagram showing a configuration example of an excitation system of a brushless generator.

FIG. 8 is a configuration diagram of a conventional automatic voltage regulator corresponding to FIGS. 1 to 3;

FIG. 9 is a block diagram of an exciter exciting current control system.

FIG. 10 is an equivalent block diagram of FIG. 9;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Generator 1a Generator field winding 2 Generator voltage detector 3 Automatic voltage regulator 4 Exciting power supply 5 Exciter exciting current detector 6 Thyristor 7 Exciter 7a Exciter field winding 8 System 9 PI controller 10 Limiter circuit 11 PI controller 12 Limiter circuit 13 Comparator 14 Comparator 14A Comparator 15 Flip-flop 16 Limit value setting circuit 17 Limit value setting circuit 18 Function generator 19 Changeover switch Ie Exciter exciting current Iec Short-time allowable maximum exciter Excitation current Iem Continuous allowable maximum exciter excitation current Vec Excitation voltage corresponding to Iec Excitation voltage corresponding to Vem Iem Vs Generator voltage set value _VA Excitation current command value α Phase angle control signal

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 9/14 H02P 9/30

Claims (4)

(57) [Claims] An exciter (7) for exciting a generator (1) in a brushless manner; A control rectifier (6) for providing a variable field voltage; and a voltage adjuster (9) for adjusting and outputting a current command value so that a voltage generated by the generator (1) becomes equal to a voltage set value.
Current adjustment for adjusting and outputting the rectification control signal so that the exciter exciting current supplied to the field winding of the exciter (7) via the control rectifier (6) becomes equal to the current command value. In the brushless generator provided with the means (11), the voltage of the excitation power supply (4) is selected to a value at which a current exceeding the short-time allowable maximum value of the excitation current can flow. Based on overcurrent determination means (13, 15) for determining that the short-time allowable maximum value has been exceeded,
Exciting current limiting means (16, 10, 12) for limiting the field voltage output from the control rectifier means (6) to a voltage at which the exciter exciting current of the shortest allowable maximum value flows. A rapid response excitation device for a brushless generator. 2. The rapid response excitation device according to claim 1,
The exciting current limiting means (16, 10, 12) limits the field voltage as described above via the means (10) for limiting the current command value output from the voltage adjusting means (9). A rapid excitation device for a brushless generator. 3. The rapid response excitation device according to claim 1,
The exciting current limiting means (16, 10, 12) limits the field voltage as described above via the means (12) for directly limiting the rectification control signal output from the current adjusting means (11). A rapid excitation device for a brushless generator. 4. The rapid response excitation device according to claim 1,
The exciting current limiting means (16, 10, 12) replaces the current adjusting means (11), and comprises the control rectifying means (6).
Means for providing the rectification control signal limited to
9) A rapid response excitation apparatus for a brushless generator, wherein the field voltage is limited as described above via 9).