JPH0251398A - Automatic voltage regulator for synchronous generator - Google Patents

Abstract

PURPOSE:To continuously variably obtain a break frequency of a phase lag-lead circuit by constituting a signal amplifying phase adjusting circuit in an automatic voltage regulator of a first-order lag amplifying circuit and a coefficient adder circuit. CONSTITUTION:An automatic voltage regulator is constituted of a voltage deviation detector 4, signal amplification phase adjusting circuit 5 and a power amplification output circuit 6. While the signal amplification phase adjusting circuit 5 is constituted of a first-order lag amplifying circuit 13 and a coefficient adder circuit 14. An output of the first order lag amplifying circuit 13 and an input signal, performing coefficient addition by the coefficient adder circuit 14, are input to the power amplification output circuit 6. The first order lag amplifying circuit 13 connects a feedback input of a feedback arithmetic capacitor 18 to a divider output of output divider resistors 19, 20. By the constitution thus obtained, stability and the transient characteristic of an automatic voltage regulating system can be set to an optimum value.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an automatic voltage regulator for a synchronous generator, and in particular, it is equipped with an AC exciter. be.

[Conventional technology]

Generally, automatic voltage regulators for synchronous generators require a disturbance prevention circuit to prevent disturbances because the automatic control loop has a high gain, but especially in those equipped with an AC exciter, the exciter output circuit That is, since the synchronous generator field circuit is a rotating body, it is difficult to construct a disturbance prevention parallel feedback circuit, and a serial amplification phase adjustment circuit, that is, a phase delay/lead circuit is used. Conventionally, a circuit shown in FIG. 2 has been used as an amplification phase adjustment circuit having this phase delay/lead characteristic.

In Figure 2, 1 is a synchronous generator, 2 is an AC exciter, and 3 is a synchronous generator.
is an automatic voltage regulator. The automatic voltage regulator is composed of a voltage deviation detector 4, a signal amplification phase adjustment circuit 5, and a power amplification output circuit 6. The voltage deviation detector detects the deviation between the set voltage and the generator voltage. The detected error signal is amplified by a signal amplification phase adjuster 5 and a power amplifier 6, and the output voltage of the synchronous generator is controlled by negative feedback to a constant value via an AC exciter 2.

The signal amplification phase adjustment circuit 5 includes an operational amplifier 7, an input operational resistor (R1) s, a feedback operational resistor (R2) 9, a high frequency feedback operational resistor (Ra) 10, a feedback operational capacitor (C) il, and a feedback operational capacitor capacity selection. It is composed of a switch 12. The signal phase adjustment circuit 5 constitutes a phase delay/lead circuit, and since the amplification factor of the operational amplifier is extremely large, its transfer function is aC, where S is the operator.

In other words, the corner point of the delay phase and the advance phase, the frequency is determined by the capacitor (C
), the capacitance of the capacitor (C) 11 is set by the selection switch 12 in accordance with the delayed phase corner frequency of the excitation circuit of the synchronous machine, and the delayed phase of the automatic control loop is compensated to the optimum value. The automatic control staff has been stabilized. As this type of amplifier, Japanese Patent Application Laid-open Nos. 61-24245 and 5
No. 7-72211 can be mentioned.

[Problem to be solved by the invention]

In the above conventional technology, since there is no suitable capacitor that can continuously vary the capacitance of the calculation capacitor for adjusting the corner frequency of the phase lag/lead phase, it is necessary to switch and set it with a selection switch, and the corner frequency of the phase lag/lead circuit The disadvantage is that it is impossible to vary the value continuously. Also, the current in the feedback circuit is extremely small.

This has the disadvantage that the contact reliability of the selection switch 12 deteriorates and the reliability of the circuit characteristics is impaired. Furthermore, to change the setting accuracy as an automatic voltage regulator.

There is a drawback that adjusting the feedback calculation resistor (R2) changes the characteristics in the low frequency region, that is, the stability.

An object of the present invention is to continuously adjust and set the phase lag and lead frequencies of a signal amplification phase adjustment circuit for phase compensation in accordance with the actual value of the field time constant of a synchronous generator, that is, the phase lag corner frequency. An object of the present invention is to provide a possible automatic voltage regulator for a synchronous generator.

[°Means to solve the problem]

In order to achieve the above purpose, the signal amplification phase adjustment circuit of the automatic voltage regulator is configured with a first-order lag amplifier circuit and a coefficient addition circuit, and the feedback input of the loop calculation capacitor of the first-order lag amplifier circuit is connected to the operational amplifier output circuit. A phase lag/lead circuit is constructed by connecting to the divided voltage output of the connected voltage dividing resistor and adding a coefficient between the output of the input signal amplified by the first-order lag amplifier circuit and the input signal, and the above-mentioned feedback The corner frequency of the phase delay/lead circuit is made continuously variable by continuously changing the voltage dividing ratio of the voltage dividing resistor which is the input point of the operational capacitor.

[Effect]

In the above-mentioned first-order lag amplifier circuit, the amount of feedback signal from the feedback calculation capacitor which inputs the divided voltage output of the voltage dividing resistor connected to the operational amplifier output circuit is determined by continuously varying the voltage division ratio of the voltage dividing resistor. This allows the capacitance of the feedback calculation capacitor to be changed equivalently to the case where the capacitance is continuously varied. Therefore, the damping effect can be continuously adjusted in accordance with the actual constant of the synchronous generator.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

16 is the same as that explained in FIG. 2, and the synchronous generator 1
Automatically controls the output voltage to a constant value using negative feedback. The signal amplification phase adjustment circuit 5 includes a first-order lag amplification circuit 13 and a coefficient addition circuit 14.

The output of the next lag amplification circuit 13 and the input signal are subjected to coefficient addition by a coefficient addition circuit 14, and are input to the power amplification output circuit 6. The first-order lag amplifier circuit 13 includes an operational amplifier 15, an input operational resistor (Rr) 16, a feedback operational resistor (Rz) 17, a negative feedback operational capacitor (c) 18, an output voltage dividing resistor (rl) 19 of the operational amplifier 15, and an input operational resistor (Rr) 16. The feedback input of the feedback calculation capacitor 18 is connected to the divided voltage output of the output voltage dividing resistor 19.20. Therefore, the transfer function of the first-order lag amplifier circuit 13 is the voltage divider division voltage rl
+r2 is extremely large and rx<:Rz, i.e. rlc<R2C
Then, R21 R11+αR2C8 The characteristic of the first-order lag amplifier circuit 13 is that the phase lag corner angle frequency changes depending on αR2 which changes the voltage division ratio α. For example, rz=1. The phase delay corner angle frequency can be varied continuously over a wide range within the ratio range of 1 to 11.

The coefficient addition circuit 14 includes an operational amplifier 21, a voltage dividing input resistor (Rla) 24 for the non-inverting input terminal (+), and a voltage dividing resistor (Rla) 24 for the non-inverting input terminal (+).
14) 25, Manual operation resistance (R1) for inverting input terminal (-)
1)22. It consists of a feedback calculation resistor (Rtz) 23, the output voltage of the first-order lag amplifier 13 is applied to a voltage dividing input resistance (Rla) 24, and an input calculation resistance (Rlt) 22.
The signal input of the first-order lag amplifier 13, that is, the output of the voltage deviation detector 4 is applied to.

Assume that the output voltage of the coefficient addition circuit has an extremely large amplification factor of the operational amplifier 21.

If R13+R14Rtt rt zt, then output voltage=(non-inverting input voltage)-(inverting input voltage)XKH. Therefore, the transmission lead phase corner angle frequency of the signal amplification phase adjustment circuit 5 = αR2C K+K)l, the frequency characteristics are phase lag and lead circuit characteristics, and low frequency region amplification factor = -(K + K1-1) high frequency region Amplification factor = -K H Rlt Lag phase corner frequency = αR2C r1+rz By making rl continuously variable, it is possible to change it continuously over a wide range, and therefore, the actual phase lag corner frequency of the synchronous generator can be easily adjusted according to the value of , and good damping characteristics, that is, optimal transient response characteristics can be achieved. Also, voltage dividing resistor (r1+rz)
By setting the current value to a value that can sufficiently improve the contact reliability of the variable resistor r1 (usually about 0.1 to 10 mA), the impedance of the feedback circuit as shown in Figure 2 is high and the current value is extremely small. The contact reliability is extremely high compared to the case where the capacitance of the calculation capacitor is switched by a circuit. Furthermore, in order to change the setting accuracy as an automatic voltage regulator, even if you change R2 and change the low frequency region amplification factor (K + K H), the change in the high frequency region amplification factor (K H) is extremely small. Therefore, there is an effect that the characteristics in the high frequency region, that is, the stability and the transient response characteristics are not changed, and the drawbacks of the prior art described in FIG. 2 are completely improved.

〔Effect of the invention〕

According to the present invention, in an automatic voltage regulator for a synchronous generator, it is possible to continuously vary the phase characteristics of the signal amplification phase adjustment circuit so as to match the actual characteristics of the synchronous generator. This has the effect that the stability and transient characteristics of the adjustment system can be set to optimal values.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an automatic voltage regulator showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional automatic voltage regulator. DESCRIPTION OF SYMBOLS 1...Synchronous generator, 2...AC exciter, 3...Automatic voltage regulator, 4...Voltage deviation detector, 5...Signal amplification phase adjustment circuit, 6...Power output Amplifier circuit, 13 first-order delay 1 figure high 2-factor

Claims (1)

[Claims] 1. In an automatic voltage regulator for a synchronous generator consisting of a voltage deviation detector, a signal amplification phase adjustment circuit, and a power amplification output circuit, the signal amplification phase adjustment circuit detects the output of the first-order lag amplifier circuit of the input signal and the input signal. A synchronous generator characterized in that the first-order lag amplifier circuit has a feedback input of a feedback capacitor for a first-order lag configuration of an operational amplifier as a divided voltage output of a voltage dividing resistor connected to an output of the operational amplifier. Automatic voltage regulator.