JPH067759B2 - Excitation adjustment device for AC generator - Google Patents

Description

TECHNICAL FIELD The invention of this application relates to an excitation adjustment device for an alternator,
Excitation adjusting device having means for relatively widening the phase controllable range of the thyristor of the control rectifier circuit for controlling the excitation circuit voltage, and the generator output voltage below the set frequency by detecting the frequency of its own generator voltage The present invention relates to an excitation adjusting device having a built-in low-frequency overexcitation preventing means for automatically drooping.

(Prior Art) As an excitation adjustment device for an AC generator, whether the generator itself has a brush or a brushless one, it has excellent controllability, settling accuracy, quick response and stability, and is economically advantageous. Therefore, generally, a thyristor phase control type automatic voltage regulator is widely used. In an automatic voltage regulator with an AC input of a single phase, in order to perform thyristor phase control of a control rectifier circuit that controls the excitation circuit voltage, so-called synchronization is used to detect the timing at which the AC input voltage crosses the zero point, as is known. A detection circuit is essential. As the synchronization detecting means, conventionally, for example, a specially prepared synchronization detecting circuit shown in FIG. 1 is provided, or a simple AC power supply synchronous relaxation oscillator circuit shown in FIG. 2 is used. That is, in FIG. 1, T is a synchronous detection transformer,
DB is a diode bridge, Z is a zener diode,
Q is an oscillating transistor, and Ra, Rb, and Rc are limiting resistors, and a synchronous pulse output is obtained from the collector of the transistor Q when the AC input crosses the zero point. The circuit shown in FIG. 2 includes the oscillation uni-junction transistor UJT, the time constant capacitor C, and the time constant resistors Rd and R.
In the relaxation oscillation circuit including e and the pulse transformer PT, by inserting the diode D into the illustrated position of the plus side power source, the plus side falls to the zero point near the zero point every AC half cycle as is known. The phenomenon is used for synchronization.

However, the device of FIG. 2 has various adverse effects because the thyristor phase control range is limited, and the low frequency overexcitation prevention circuit is added regardless of the fact that the device is developed for simplification. However, there is a drawback in that the circuit configuration must be complicated rather than the method shown in FIG. That is, in the device shown in FIG. 2, the so-called synchronization period in which the plus side falls to the zero point is relatively long due to its configuration, and the thyristor phase control range is limited. In the case of control by a single-phase mixed bridge rectifier circuit, the maximum value of the DC output voltage is suppressed and the desired value is not obtained, or the minimum value can not be controlled to zero voltage and a finite voltage remains, etc. Often occurred. For this reason,
For generators in the small capacity range where the output voltage of the generator to be controlled has poor responsiveness to load fluctuations, etc., and the excitation voltage is relatively low, the uncontrollable area of the operating range is included, and it remains practical. There was a case where it could not be used for. Further, in the device of FIG. 2, since the synchronization period is relatively long, the so-called low frequency overcurrent phenomenon, which will prevent the generator from overexciting when the generator goes into low frequency operation for some reason, which will be described later. If an excitation prevention circuit is added, a complicated waveform shaping circuit is required, and as a result, a more complicated circuit configuration than that of the method shown in FIG. 1 has to be adopted, which is simplified as shown in FIG. The significance of using the synchronization detection circuit has been lost.

Here, a conventional low frequency overexcitation preventing means will be described.
If the frequency of the generator is lowered below the rated frequency while the set voltage of the generator excitation adjustment device remains constant, the excitation adjustment device attempts to keep the generator output voltage at the set voltage, as is known. The generator exciting current is controlled to increase, and depending on the operating frequency, the field winding of the generator may be burned out, leading to a serious accident. In addition, engine generators often perform idling at a frequency of 50 to 60% of the rated frequency to protect the prime mover immediately after starting operation or immediately before stopping, or in the case of an intermittent load, to wait for fuel saving of the prime mover. It may switch to idling operation during operation, or temporarily perform low frequency operation for maintenance of the prime mover. In such a case, conventionally, (1) the generator field breaker and breaker are manually turned on and off each time, (2) the field breaker and breaker are turned on and off in conjunction with the idling operation switch, (3) For example, a small generator for speed detection attached to the shaft end of the generator, the speed of the main generator (proportional to the frequency)
And a separate speed relay to turn on and off the field breaker and disconnector, (4) The above detection signal is applied to the addition input of the high gain amplifier in the automatic voltage regulator, and the predetermined frequency is applied. In the following, measures such as issuing a voltage reduction command, or controlling or disconnecting it to de-energize were taken, but these measures require manual operation, or special generator for speed detection or It requires a relay and its control function was not sufficient.

(Purpose) A first invention of the present application is an improvement of a conventional AC power source synchronous type generator excitation adjusting device as shown in FIG. 2, and a thyristor having a relaxation oscillation circuit for controlling an excitation circuit of the generator. In the phase control excitation adjusting device or the like, it is possible to detect the synchronization signal as a pulse signal narrowed to a practically unimpeded range and relatively widen the phase control range of the control rectification circuit of the excitation circuit. An object of the present invention is to provide an excitation adjustment device for an AC generator.

The second invention of this application is an improvement of the conventional AC power supply synchronous type generator excitation adjusting device, and is particularly useful in a thyristor phase control excitation adjusting device having a relaxation oscillation circuit for controlling the generator excitation circuit. It has excellent controllability and reliability that can detect the frequency of its own generator voltage and automatically drop the generator output voltage below the set frequency without providing a speed detecting generator or relay. It is an object of the present invention to provide an excitation adjustment device for an AC generator that incorporates low frequency overexcitation preventing means.

Further, the first and second aspects of the present invention utilize the multi-input high gain amplifier, and each of the above-mentioned objects can be achieved by a simple circuit, whereby a compact structure is achieved, and economically. An object of the present invention is to provide an advantageous excitation adjustment device for an AC generator.

Furthermore, the first and second inventions achieve the above-mentioned objects, respectively, and apply the above control circuit to both the high-voltage generator and the low-voltage generator in common for both the brush type and the brushless type. It is an object of the present invention to provide an excitation adjustment device for an AC generator that can be used.

(Summary of the Invention) A first invention of the present application is to provide a directional synchronous detection element in a circuit having a first polarity with respect to a reference potential in an output circuit of a rectifier circuit for rectifying a generator output voltage, In the output circuit of the rectifying circuit, a constant voltage element and a non-linear resistance element effectively connected in series to the reference voltage setting section having a second polarity which is the opposite polarity to the reference potential with respect to the reference potential. And a second voltage corresponding to a voltage drop in the non-linear resistance element and a first voltage obtained from a terminal of the synchronization detection element having a relatively first polarity in the synchronization detection circuit. The relaxation oscillation circuit for controlling the exciter circuit of the generator is synchronized with the synchronization signal having a narrow pulse width obtained by comparison.

A second invention is a frequency / voltage detection circuit,
It is a function of the amount of decrease in the generator frequency only when the generator frequency is decreased by comparing the voltage that changes in one direction with time and is reset by the output signal of the synchronization detection circuit with a settable reference voltage. A control signal is generated and the relaxation oscillation circuit for controlling the exciter circuit of the generator is controlled by the signal that is the sum of this control signal and the signal that is a function of the output voltage of the generator detected by the voltage detection circuit. It is controlled to prevent overexcitation of the field when the field is lowered.

(Embodiment) An embodiment of the invention of this application will be described in detail below with reference to FIGS. 3 to 6. The following description will be made in the order of the configuration of the embodiment of the invention of this application, its general operation, its synchronization detection operation, and its low-frequency overexcitation prevention operation for an example in which the invention of this application is applied to a brushless generator. . The invention of this application can be similarly applied to a brush-equipped generator.

(Structure of the embodiment of the invention of this application) (FIG. 3) In FIG. 3, 1 is an AC generator, 2 is its field winding,
Reference numeral 3 is an armature of the exciting wire, and 4 is its field winding. Reference numeral 5 is a rotary rectifier mounted on the rotating part of the generator 1 and is an exciter armature 3
Is for rectifying the output of the magnetic field winding 2 to excite the field winding 2, and is configured by, for example, connecting a diode in a bridge.
Reference numeral 6 denotes a control rectifier circuit for an exciter machine composed of a thyristor and a diode. In this example, the control circuit described later has a common configuration regardless of whether it is a single-phase half-wave rectifier circuit or a single-phase mixed bridge rectifier circuit. It is configured for practical use. Note that the single-phase half-wave rectifier circuit is mainly for low-voltage generators, and in principle a transformer for exciter is not provided.The single-phase mixed bridge type rectifier circuit is mainly for high-voltage generators, and is not for exciter transformer. It has a container.

Reference numeral 7 is a transformer for extracting a voltage component related to the terminal voltage of the generator 1, 8 is a converter for converting the output of the transformer 7 into a DC voltage, and a signal related to the terminal voltage of the generator 1, generally power generation. It is a voltage detection circuit for extracting a signal that is a function of the output voltage of the machine 1, and the detection signal amount can be adjusted by a variable resistor connected to the outside. Reference numeral 9 is a single-phase full-wave rectification circuit for a control circuit, which is composed of, for example, a diode bridge, and its rectified output is applied to constant voltage zener diodes Z1 and Z2 via an input resistor R2.
1 and Z2 are applied to the zener diodes Z1 and Z
Reference of the control power supply circuit 2 of the connection point, i.e., the OV line, Tsu first polarity from Zener diode Z1 via a backflow prevention diode D1, for example, to obtain a positive control supply voltage, the Zener diode Z ₂ from the second , A negative control power supply voltage, for example. The control power supply voltages of the first and second polarities are respectively smoothing capacitors C.
6 and C7 are used for smoothing. Further, the resistor R1 inserted in parallel with the rectifier circuit 9 has a minimum level on the negative side where the zero level of the single-phase full-wave rectified output waveform of the rectifier circuit 9 is determined by the Zener diode Z2 ((-() in FIG. 4 (a)). ) Line) so that the rectified output waveform surely drops to the (-) line in Fig. 4 (a) described later so that the AC input voltage of the rectifier circuit 9 drops. This is also for surely obtaining a sync pulse having a narrow sync period described later.

10 is a relaxation oscillator circuit, 11 is an amplifier circuit, and 12 is frequency /
A voltage detection circuit (hereinafter referred to as F / V detection circuit), 13 is a reference voltage setting unit (in this example, a negative reference voltage setting unit),
Reference numeral 14 denotes a synchronization detection circuit, which constitutes a main part of the excitation control system. The configuration of each circuit will be described in detail below.

The relaxation oscillation circuit 10 is for controlling the thyristor of the control rectification circuit 6 for the exciter machine, and this circuit includes a uni-junction transistor UJT, a pulse transformer PT,
A capacitor C1 and resistors R3 and R4 of the time constant circuit, transistors T1 and T2, input resistors R5a and R5b, and diodes D2 to D4 are connected as shown in the figure. A signal amplified by an amplifier OP1 described later is applied to the transistor T1 via an input resistor R5a, which accelerates charging of the capacitor C1 of the time constant circuit,
An output pulse of a high gain amplifier OP3, which will be described later, is applied to the transistor T2 via a diode D4 and an input resistor R5b, whereby the capacitor C1 of the time constant circuit is discharged, and a series of these operations is performed. The uni-junction transistor UJT is on / off controlled, and the relaxation oscillation circuit 10 is synchronously controlled.

In this example, the amplifier circuit 11 has a plus detection signal, that is, a signal obtained by integrating a detection signal of the voltage detection circuit 8 input through the input resistor R8 and an output signal of a high gain amplifier OP2 described below input through the input resistor R9. In this example, it is for amplifying the negative voltage setting signal, that is, the deviation amount from the signal from the negative reference voltage setting unit 13 input through the input resistor R10. High gain amplifier OP
The deviation amount of the detection signal, the voltage setting signal, and the integrated signal is input to the inverting input of 1, and the non-inverting input is connected to the 0V line via the resistor R21. The resistor R6 is a feedback resistor of the high gain amplifier OP1, and the capacitor C2 and the resistor R7 connected in series constitute a compensation circuit.

The F / V detection circuit 12 can be used only when the generator output frequency is in the low frequency range when the engine is idling as described above.
A high-gain amplifier OP, which operates as a comparator, for dropping the output voltage of this excitation regulator at a set frequency or lower to prevent overexcitation of the generator field.
The inverting input of 2 is connected to the 0V line via resistor R22,
The non-inverting input has a capacitor C of a sawtooth wave generating circuit composed of a resistor R15 and a capacitor C4 connected in series.
The positive voltage applied to 4 and the negative voltage determined by the setting of the set frequency adjusting resistor VR1 are input resistance R13.
And R14 and compared. Capacitor C
A pulse obtained by differentiating an output pulse of a high gain amplifier OP4, which will be described later, is input to a transistor T3 connected in parallel with the transistor T3 via a diode D6, whereby a capacitor C4 is generated.
The electric charge of is discharged, and the sawtooth voltage waveform rising in one direction shown in FIG. 5 (a) is reset. The output of the high gain amplifier OP2 is integrated by the integrating capacitor C3 and the integrating resistor R11 via the output resistor R12 and the diode D5 and input to the high gain amplifier OP1.

The reference voltage setting unit 13 is connected in series between the 0V line and the (−) line, and includes a diode D7 that is an example of a non-linear element, a constant voltage Zener diode Z3 that is an example of a constant voltage element, and a current limiting resistor R16. It is composed of The diode D7 also has the temperature compensation function of the reference voltage setting unit 13 in this example, and although only one diode D7 is shown in the drawing, it may be composed of a plurality of diodes. , The diode D7 is directly connected in series to the zener diode Z3, but it is sufficient that this is effectively connected in series.

The synchronization detection circuit 14 is for supplying a later-described synchronization pulse to the relaxation oscillation circuit 10 and the F / V detection circuit 12. High-gain amplifier OP that both operate as a comparator
In this example, the anode side voltage of the diode D1 and the diode D of the reference voltage setting unit 13 are connected to the inverting inputs of 3 and OP4.
The voltage corresponding to the voltage drop of the encircling layer of 7 is the input resistance R
18 and R19, and its non-inverting input is connected to the 0V line via the resistor R23. High gain amplifier
The output of OP3 is input to the transistor T2 of the relaxation oscillator circuit 10 as described above, while the output of the high gain amplifier OP4 passes through the resistor R17, the capacitor C5 and the resistor R17 'forming the differentiating circuit to F / It is input to the transistor T3 of the V detection circuit 12.

Each of the high gain amplifiers OP1 to OP4 described above is configured to effectively utilize one multi-input high gain operational amplifier, so that the number of active and passive elements to be used can be reduced as much as possible and the circuit configuration is simple. Therefore, in order to carry out the invention of this application, these amplifiers do not have to be of a multi-input type, and each amplifier is configured by combining a plurality of amplifiers. May be.

(General operation of the embodiment of the invention of this application) (FIG. 3) Next, the operation of the excitation adjusting device of the alternator according to the invention of this application shown in FIG. 3 will be described. As is well known, the operation of the main circuit in the steady state is such that the voltage component extracted from the generator output or via the exciting transformer is rectified by the first rectifier circuit 6, and the rectified output is supplied to the exciter. In addition to exciting the field winding 4, the output of the armature 3 of the exciter is rectified by the rotary rectifier 5, and the rectified output is supplied to the field winding 2 of the main machine 1 to perform a predetermined excitation. is there.

The adjustment of the excitation power applied to the field winding 4 of the exciter is the third
The apparatus shown in the figure operates as follows. That is, the signal input to the amplification circuit 11 of the excitation control system is the voltage detection circuit 8
Since the voltage detection signal and the output signal of the F / V detection circuit 12 are added to the same polarity and the reference signal from the reference voltage setting unit 13 which is input in the opposite polarity to this signal, A signal obtained by amplifying the deviation amount between the added output signal and the reference signal by the high gain amplifier OP1 to which a predetermined negative feedback is applied is input resistor R5.
By adding to the transistor T1 via a, the capacitor C1 of the time constant circuit is charged and discharged by turning on the transistor T2 controlled by the output of the high gain amplifier OP3 of the synchronization detection circuit 14, and By controlling the on-phase of the uni-junction transistor UJT of the relaxation oscillator circuit 10 by the charging voltage, the thyristor of the control rectifier circuit 6 is phase-controlled via the pulse transformer PT, and the DC output of the control rectifier circuit 6, that is, the excitation. The excitation power supplied to the machine field winding 4 is adjusted, and the generator output voltage is automatically controlled according to the set reference. In a steady state, the above series of operations is performed.

(Synchronization detection operation of the embodiment of the invention of this application) (FIGS. 3 and 4) Next, the synchronization detection operation of the embodiment of FIG. 3 will be described. This is the same as the first invention of this application. It realizes the main characteristics. The inverting input of the high gain amplifier OP3, OP4 to operate as a comparator, the anode voltage V _R18 of the inserted rectifier circuit 9 to the positive output side diode D1
(See FIG. 4 (a)) and the cathode side voltage V _R19 of the diode D7 of the reference voltage setting unit 13 are input.
FIG. 4 shows voltage waveforms at various parts of the circuit.
V _{R1 in} (a) shows a waveform obtained by single-phase full-wave rectifying the voltage generated by transforming the generator output voltage by the transformer 7, and at this time, the anode side voltage V _R18 of the diode D1 is a solid line in the figure. The waveform becomes as shown by, and the cathode side voltage V of the diode D7
_The voltage -V _R19 obtained by inverting the polarity of _R19 has a waveform shown by a solid line just above the 0V line. Here, only in a range where −V _R19 is larger in absolute value of voltage than + V _{R18, the} sync pulse having a narrow sync period shown by the solid line P ₁ in FIG. 7B is output to the outputs of the high gain amplifiers OP3 and OP4 which operate as comparators. Is obtained. In this case, the rectified waveform V _R1 surely drops to the (−) line in FIG. 9A due to the action of the resistor R1 inserted in parallel with the rectifier circuit 9, so that the voltage difference between −V _R19 and + V _R18. Even if is small, the above-mentioned pulse is surely obtained, and no malfunction occurs.

The output pulse of the high gain amplifier OP3 is transmitted through the diode D4 and the input resistor R5b to the transistor T of the relaxation oscillation circuit 10.
2 becomes a signal for discharging the charge stored in the capacitor C1 of the time constant circuit (charged by the transistor T1 which conducts at the output of the high gain amplifier OP1), and is used for synchronizing the relaxation oscillation circuit 10. Also high gain amplifier OP4
Output pulse of resistor R17, capacitor C5 and resistor R
The signal is differentiated by the differentiating circuit composed of 17 ', and becomes a signal for discharging the charge charged in the capacitor C4 of the sawtooth wave generating circuit of the F / V detection circuit 12.

According to the third device, as described above, the reference voltage setting unit 1
High-gain amplifier operating as a comparator with a signal level corresponding to the armpit voltage drop of the temperature compensating diode D7 of No. 3
By inputting a reference voltage to OP3 and OP4 (particularly OP3), a relatively narrow sync pulse width can be obtained within a range that does not hinder control. In contrast,
In the conventional simple type AC power supply synchronous relaxation oscillator shown in FIG. 2, synchronization is lost during the drop period from the V _R18 line in FIG. 4 (a), and the dotted line in FIG. 4 (b). P ₂
As shown in (3), since the synchronization pulse width is considerably widened, it is likely that the generator output voltage cannot be controlled to the minimum value of zero voltage, and other adverse effects are likely to occur.

(Low-frequency over-excitation prevention operation of the invention of this application) (FIGS. 3 to 6) Next, the low-frequency over-excitation prevention operation of the embodiment of FIG. 3 will be described. It realizes the main features of the invention. The high gain amplifier OP2 of the F / V detection circuit 12 of FIG. 3 also operates as a comparator, and its non-inverting input has a reference set voltage V _{R14 as} shown in FIG.
(The setting value can be changed with the variable resistor VR1,
The output voltage droop setting frequency, which will be described later, can be changed) and the charging voltage (sawtooth wave voltage) V _C4 of the capacitor C4 of the sawtooth wave generation circuit are input, and the charging voltage V
_When the magnitude of _C4 becomes larger than the absolute value of the set voltage V _R14 , the high gain amplifier OP2 outputs the pulse voltage P ₄ shown in FIG. 5 (c) during that period. The capacitor C4 is normally charged through the resistor R15, so that the voltage V _C4 rises in one direction, but the differential pulse (fifth, fifth) by the differential circuit (R17, C5, R17 ') on the output side of the high gain amplifier OP4. P in Figure (b)
_{When the} transistor T3 is turned on in ₃ ), it is discharged. That in synchronism with the generator output frequency capacitor C4 repeating the charging and discharging, but the charge voltage of the capacitor C4 in the differential pulse P ₃ is the generator output frequency within the rated frequency is reset to 0V. Here, the synchronization pulse is converted into the differential pulse because the charging voltage level of the capacitor C4 relatively rises as the frequency decreases and the power supply cycle lengthens, whereas the width of the synchronization pulse is changed. This is because the charging voltage of the capacitor C4 becomes longer and the discharging period of the charging voltage of the capacitor C4 becomes longer, so that the peak value of the voltage V _C4 does not increase in proportion to the decrease in frequency, and a desired generator drooping characteristic cannot be obtained.

Well pulse voltage P ₄ shown in FIG. 5 which is output from the high gain amplifier OP2 (c), the negative side is Katsuhito by the diode D5, only positive pulse voltage is integrated by the integrating capacitor C3 and the resistor R11. Then, since the integrated voltage V _C3 shown in FIG. 5 (c) and the signal voltage detected by the voltage detection circuit 8 are added and input to the high gain amplifier OP1, for example, the generator output frequency is lowered. Then, the level of the integrated capacitor voltage V _C3 gradually rises as shown in FIG. 5 (c), which causes the output of the high gain OP1 to turn off the transistor T1 and the time constant circuit (R3, C3).
The charging time constant of 1) becomes large, the relaxation oscillation circuit 10 operates in the electric phase lowering direction, and prevents overexcitation of the generator field during low frequency operation.

FIG. 5 illustrates the operation of the F / V detection circuit 12 described above. The frequency of the generator 1 gradually decreases from the rated value for some reason, and the F / V detection circuit 12 detects the undetected area. It shows the situation of shifting to the region (generator voltage drooping characteristic region). FIG. 11A shows the relationship between the charging voltage + V _C4 of the capacitor C4 of the time constant circuit and −V _R14 in which the polarity of the operating frequency setting voltage V _R14 is inverted, and FIG. 9B shows the charging voltage V _C4.
Shows a synchronous differential pulse signal P ₃ for resetting the generator in synchronism with the frequency of the generator 1, and FIG. 7C shows the output P ₄ of the high gain amplifier OP2 and the output voltage V _{C3 of the} F / V detection circuit 12. And 0V in the figure is 0V of the control circuit.
Shows the line. FIG. 6 shows an example of the frequency characteristics of the generator output voltage when the low-frequency overexcitation prevention function operates in the device of FIG. 3, where F _O is the rated value of the generator frequency and F _S is the output. The voltage droop setting frequency, V _O, is the rated value of the generator output voltage.

(Effect) As described in detail above, according to the first invention, the second
The reference voltage setting unit 13 that outputs the reference voltage to the control electric wire having the polarity of 1 is provided, and the voltage of the first constant voltage element Z1 and the reference voltage setting unit that are connected to the output side of the single-phase full-wave rectification circuit by the synchronization detection circuit Since the relaxation oscillation circuit that controls the exciter circuit of the generator is synchronized by the synchronization signal with a narrow pulse width obtained by comparing with the reference signal from, the thyristor phase control excitation adjustment device, etc. Is narrowed to a range that does not hinder practical use, and the phase controllable range is relatively widened. In particular, the minimum value side can be controlled to zero voltage.

According to the second aspect of the invention, the voltage / voltage detection circuit changes in one direction with time and is reset by the output signal of the synchronization detection circuit, and the settable reference voltage is compared, A control signal that is a function of the amount of decrease in the generator frequency is generated only when the frequency decreases, and a signal that is the sum of this control signal and the signal that is the frequency of the output voltage of the generator detected by the voltage detection circuit Since the relaxation oscillation circuit for controlling the exciter circuit is controlled so as to prevent overexcitation of the field when the generator frequency is lowered, it is not necessary to provide a speed detecting generator or relay, etc. It is possible to incorporate a low-frequency overexcitation prevention unit having excellent controllability and reliability capable of detecting the frequency of its own generator voltage and automatically drooping the generator output voltage below a set frequency.

Further, if the amplifier of the synchronous detection circuit in the first invention and the amplifier of the frequency / voltage detection circuit in the second invention are configured as a multi-input high gain amplifier, the number of parts can be reduced and the cost can be reduced by a simple circuit configuration. it can.

Furthermore, the first and second inventions can be applied to both the high-voltage generator and the low-voltage generator with the control circuit in common, regardless of whether they have a brush or a brushless system.

[Brief description of drawings]

1 and 2 are circuit diagrams of a conventional excitation adjustment device for an AC generator, FIG. 3 is a circuit diagram of an excitation adjustment device for an AC generator of this application, and FIGS. 4 (a) and 4 (b) are Waveform diagram for explaining the synchronization detection operation in the device of FIG. 3, FIGS. 5 (a), (b) and (c)
Is a waveform diagram for explaining the low frequency overexcitation prevention operation in the device of FIG. 3, and FIG. 6 is an explanatory diagram of the frequency characteristics of the generator output voltage in the low frequency overexcitation prevention operation of the device of FIG. DESCRIPTION OF SYMBOLS 1 ... AC generator, 2 ... its field winding, 3 ... exciter armature, 4 ... its field winding, 6, 9 ... rectifier circuit, 8 ... voltage detection circuit, 10 ... relaxation oscillation Circuit, 11 ... Amplifier circuit, 12 ...
F / V detection circuit, 13 ... Reference voltage setting section, 14 ... Synchronization detection circuit, D1 ... Diode which is an example of backflow prevention element, D
7 ... A diode which is an example of a non-linear resistance element, Z3 ... A Zener diode which is an example of a constant voltage element.

Claims (1)

[Claims] 1. A full-wave rectifier circuit (9) for rectifying an output voltage of a generator, and a series circuit of first and second constant voltage elements (Z1, Z2) connected in parallel with the rectifier circuit, Smoothing circuits (C6, C7) for smoothing the first and second constant voltage element voltages to obtain control power sources of the first and second polarities, and the first constant voltage element (Z1) side from the first control power source Power supply circuit comprising a backflow prevention element (D1) for preventing backflow to the control circuit, a non-linear resistance element (D7) connected to the control power supply of the second polarity, a third constant voltage element (Z3) and a resistor. (R1
6) a reference voltage setting unit (13) composed of a series circuit, a terminal voltage of the first constant voltage element (Z1) and a terminal voltage of the non-linear resistance (D7) are compared, and a synchronization signal is output. First and second synchronization detection means (OP3 and OP4), and sawtooth wave voltage generation means (R) reset by the synchronization detection signal detected by the second synchronization detection means (OP4).
15, C4, T3) and a means (OP2, C3, R11) for comparing and integrating the sawtooth wave voltage and the reference voltage set by the reference voltage setting unit (13) to lower the generator frequency. A frequency / voltage detection circuit (12) that generates a control signal that is a function of the amount of decrease in the generator frequency only, a voltage detection circuit (8) that detects the output voltage of the generator, and the frequency / voltage detection circuit ( Synchronization control by an amplifier circuit (11) that adds and amplifies the control signal from 12) and the signal detected by the voltage detection circuit (8), and the synchronization signal detected by the first synchronization detection means (OP3) The ON phase is controlled by the signal of the amplifier circuit (11) and the exciter circuit (2-6)
A relaxation oscillation circuit for outputting a signal for controlling the phase of the control rectifier circuit (6), and an excitation adjustment device for an AC generator, comprising: