JP2001339997A - Automatic regulator of synchronous generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic voltage regulator capable of stably controlling the voltage of a synchronous generator. SOLUTION: The automatic regulator of the synchronous generator is provided with a direct current power source supplying direct current to the serial circuit of a switching element regulating the field coil and the field voltage of the synchronous generator, a diode connected to the field coil in parallel, an arithmetic amplifier for compensating the fluctuation of generator characteristics accompanying the fluctuation in load impedance on the basis of a voltage detector detecting the terminal voltage of the synchronous generator and the output signal of a voltage instruction signal generator and outputting a control signal for holding the voltage of the synchronous generator at prescribed voltage, a correction signal output device for outputting a correction signal for correcting the fluctuation of inductance due to the saturation of the field coil on the basis of the rotary speed signal of the synchronous generator detected by a rotary speed detector, a multiplier for multiplying the output signal of the correction signal output device and the output signal of the arithmetic amplifier, and a pulse width modulator for outputting the pulse voltage of an on-period proportional to the output signal of the multiplier and switching a switching element. Even in the case that the rotary speed of the synchronous generator is changed, the fluctuation of the inductance of the field coil due to saturation characteristics is corrected, and stable voltage control is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic voltage regulator of a synchronous generator for automatically controlling an output voltage of a synchronous generator or a brushless synchronous generator (hereinafter abbreviated as a synchronous generator) to a desired voltage.

2. Description of the Related Art A conventional automatic voltage regulator of a synchronous generator will be described with reference to FIG.

[0002] As shown in the figure, a rotor of a synchronous generator 1 is rotated by a prime mover 9, and the generated power is supplied to a load 10. The diode 2 is connected in parallel with the field winding of the synchronous generator 1 so that the cathode terminal is in the direction of the positive output terminal of the DC power supply 3. It has a flywheel function to secure the path through which the air flows.

The operational amplifier 7 detects a command signal Vs output from the voltage command signal generator 6 and a terminal voltage of the synchronous generator 1 as command signals for controlling the voltage of the synchronous generator 1 to a desired voltage. A control operation is performed based on the output signal Vd of the voltage detector 5 to compensate for variations in generator characteristics due to variations in load impedance, and the field voltage is adjusted so that the voltage of the synchronous generator becomes a desired voltage. ON of control signal to operate
-Output a duty signal. The pulse width modulator 8 uses this o
A pulse signal V having an ON width proportional to the n-duty signal
p, and the switching element 4 performs a switching operation according to the pulse signal Vp.

The switching element 4 is connected in series to the field winding of the synchronous generator 1, and a DC field power supply voltage Vfs is applied to these series circuits by the DC power supply 3.
Further, the switching element 4 performs a switching operation according to the pulse signal Vp, thereby chopper-operating the field power supply voltage Vfs, and adjusting the average voltage Vf applied to the field winding of the synchronous generator 1.

The automatic voltage regulator of the synchronous generator 1 configured as described above automatically adjusts the applied amount of the field voltage Vf even if the output voltage of the synchronous generator 1 fluctuates due to the fluctuation of the load. Therefore, the output voltage of the synchronous generator 1 can be controlled to a desired voltage.

[0006]

The saturation characteristic of the field winding of the generator is shown in the graph of FIG. Assuming that the field current during the rated voltage operation is if1 in the ordinary generator device as shown in FIG. 3, the field magnetic flux required to generate the nominal induced voltage at that time is Φ1. When considering a generator voltage automatic control system for disturbances such as load fluctuations,
What is necessary is just to know the transfer function of the generator in the minute fluctuation range from the operating point A at the time of rating. Therefore, the amplification factor of the field magnetic flux Φ1 with respect to the field current if1 may be approximated by the slope of the tangent at point A of the saturation characteristic in FIG. 4, considering the inductance of the field winding at if1.

Now, as an example, considering the case where the rotation speed of the prime mover is increased, since the output voltage of the generator is proportional to the number of interlinkage magnetic fluxes of the field winding, if the field current is maintained at if1, Generator output also increases. Accordingly, the automatic voltage regulator operates to reduce the field current to if2 in FIG. 4 and to reduce the number of interlinkage magnetic fluxes from Φ1 to Φ2 in order to maintain the generator voltage at the desired voltage. As a result of such control, the state of the field winding shifts to the point B in FIG. 4, but since the saturation characteristic of the field winding draws a curve, the slope of the tangent differs between the points A and B. . Therefore, the inductance of the field winding differs between the points A and B, and the amplification factor of the field magnetic flux with respect to the field current changes. Since the rotation speed is kept almost constant in a normal power generator, such fluctuations can be ignored,
If the generator is driven by a prime mover whose rotational speed fluctuates greatly, such as an automobile engine, if the voltage is stably controlled at the point A, the voltage at the point B can be controlled even if the voltage is stably controlled at the point A unless the fluctuation of the amplification factor is considered. May cause upset.

The present invention has been made in order to cope with the above situation. Even when the rotation speed of the rotor greatly changes and the amount of field current required for outputting the rated voltage changes greatly, the field characteristics due to the saturation characteristics are obtained. An object of the present invention is to provide an automatic voltage regulator for a synchronous generator that can stably control a synchronous generator voltage by correcting a variation in winding inductance.

[0009]

In order to achieve the above object, an automatic voltage regulator of a synchronous generator according to the present invention is connected in series to a field winding of the synchronous generator and performs a switching operation. A switching element that adjusts a field voltage, a DC power supply that supplies a DC voltage to a series circuit including the field winding and the switching element, and a DC power supply connected in parallel to the field winding and A diode having a cathode terminal connected to a side output terminal, a voltage detector for detecting a terminal voltage of the synchronous generator, a voltage command signal generator for outputting a voltage command signal, the voltage detector and the voltage command signal. A control operation is performed based on a signal output from the generator to compensate for a change in generator characteristics due to a change in load impedance, and to output a control signal for keeping the voltage of the synchronous generator at a desired voltage. An operational amplifier, a rotation speed detector for detecting a rotation speed of the synchronous generator, and a correction signal for correcting a change in inductance due to saturation of the field winding based on a signal from the rotation speed detector. A correction signal output device, a multiplier for multiplying the output signal of the first correction signal output device and the output signal of the operational amplifier, and a pulse voltage in an ON period proportional to the output signal of the multiplier. A pulse width modulator for performing a switching operation of the switching element, so that even when the rotation speed of the synchronous generator changes, the fluctuation of the inductance due to the saturation of the field winding due to the saturation characteristics is corrected, and stable voltage control is performed. It is characterized in that it can be performed.

According to a second aspect of the present invention, in the automatic voltage regulator for a synchronous generator according to the first aspect, a brushless synchronous generator is used in place of the synchronous generator and based on an output signal of a rotation speed detector. A second correction signal output unit for outputting a correction signal for correcting a variation in inductance due to saturation of a field winding of the exciter; the multiplier includes an output signal of the operational amplifier and an output signal of the first correction signal output unit; And the output signal of the second correction signal output device, even when the rotation speed of the brushless synchronous generator changes, the inductance of each field winding due to the saturation of the respective field windings due to the saturation characteristics of the synchronous generator and the exciter. It is characterized in that the fluctuation is corrected so that stable voltage control can be performed.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of an automatic voltage regulator of a synchronous generator according to one embodiment (corresponding to claim 1) of the present invention.

As shown in FIG. 1, this embodiment is different from the conventional automatic voltage regulator of the synchronous generator shown in FIG. 3 which has already been described, in that a rotation speed detector 20 and a first correction signal output are provided. And a multiplier 22. Since the other components are the same, the same parts are denoted by the same reference numerals and the description thereof will not be repeated.

Next, the operation of the main components of this embodiment will be described. The operational amplifier 7 includes a command signal Vs output from the voltage command signal generator 6 as a command signal for controlling the voltage of the synchronous generator 1 to a desired voltage;
Control operation is performed based on the output signal Vd of the voltage detector 5 for detecting the terminal voltage of the synchronous generator to compensate for variations in generator characteristics due to variations in load impedance so that the voltage of the synchronous generator becomes a desired voltage. Of the control signal for operating the field voltage
An n-duty signal is output.

The rotation speed detector 20 detects the rotation speed of the synchronous generator 1 or the frequency of the output voltage, and outputs a signal Vrpm proportional to the detected rotation speed or frequency. First correction signal output device 21
Receives the signal Vrpm and outputs a correction signal Va based on the saturation characteristic of the generator field winding. In the saturation characteristic shown in FIG. 4, for example, if if1 is a rated field current at a reference rotational speed and if2 is a rated field current at an arbitrary rotational speed, the correction signal Va has a tangent slope at point B (that is, i
The slope of the tangent at point A to the inductance at f2) Lb (ie, the inductance at if1) La
Is a correction signal obtained by the ratio La / Lb.

The multiplier 22 includes a first correction signal output unit 21
And the on-du of the output signal Va of the operational amplifier 7
The ty signal is multiplied to output an on-duty2 signal of the control signal. Further, the pulse width modulator 8 has an on-duty
A pulse signal Vp having an ON width proportional to the two signals is output, and the switching element 4 performs a switching operation according to the pulse signal Vp.

Here, the output signal of the operational amplifier 7 is turned on-
Multiplying the duty signal by the correction signal Va means that when the rotation speed fluctuates from the reference rotation speed, the fluctuation of the inductance of the field winding due to the saturation characteristics of the generator field winding is corrected inside the control device, and the power generation is performed. This means that the fluctuations are canceled out and can be ignored in the entire machine voltage control system.

The switching element 4 is connected in series to a field winding of the synchronous generator 1, and a DC power supply 3 applies a field power supply voltage Vfs to these series circuits. The switching element 4 performs a chopper operation on the field power supply voltage Vfs by performing a switching operation according to the pulse signal Vp, and adjusts the average voltage Vf applied to the field winding of the synchronous generator 1. The diode 2 is connected in parallel to the field winding of the synchronous generator 1, and has a cathode terminal connected in the direction of the positive terminal of the DC power supply 3.

The present embodiment is provided with the components having the above-described functions, so that the inductance of the field winding, which changes with the increase and decrease of the field current of the synchronous generator due to the rotation speed fluctuation, can be changed by the first correction signal. Output signal Va of output device 21
Thus, a stable generator output voltage can be obtained by the same control method as in the related art even in a power generator connected to a prime mover whose rotational speed frequently fluctuates.

FIG. 2 is a circuit diagram of an automatic voltage regulator of a synchronous generator according to another embodiment (corresponding to claim 2) of the present invention. As shown in FIG. 2, this embodiment differs from the embodiment of FIG. 1 already described in that a brushless synchronous generator is connected in place of the synchronous generator and a second correction signal output unit 23 is added. And the other components are the same. Therefore, the same parts are denoted by the same reference numerals, and the duplicate description will be omitted.

Next, the operation of the components of this embodiment will be described. The second correction signal output unit 23 receives the output signal Vrpm of the frequency detector as an input and outputs a correction signal Vb based on the saturation characteristics of the field winding of the exciter. In the saturation characteristic shown in FIG. 4, for example, if the ifef1 is the exciter rated field current at a reference rotational speed and the iff2 is the exciter rated field current at an arbitrary rotational speed, the correction signal Vb has the slope of the tangent at point F ( That is, the inductance at ifef2) L
This is a correction signal determined by the ratio Le / Lf of the slope of the tangent at point E to f (ie, the inductance at ifef1) Le.

The multiplier 22 includes a first correction signal output unit 21
Is multiplied by the output signal Va of the second correction signal output unit 23 and the on-duty signal of the output signal of the operational amplifier 7 to output a control signal on-duty3.

Here, the output signal of the operational amplifier 7 is turned on-
By multiplying the duty signal by the correction signals Va and Vb, when the rotation speed fluctuates from the reference rotation speed, the fluctuation of the inductance of each field winding due to the saturation characteristics of the generator and the exciter is corrected in the control device. This means that in the entire generator voltage control system, the fluctuation is offset and can be ignored.

The present embodiment is provided with the components having the above-described functions, so that the inductance of each field winding, which fluctuates according to the increase and decrease of the field current of the generator and the exciter due to the rotation speed fluctuation, is set to the first value. The output signal Va of the correction signal output device 21 and the output signal V
b, it is possible to obtain a stable generator output voltage by the same control method as in the related art even in a generator connected to a prime mover whose rotational speed frequently fluctuates.

[0024]

As described above, the present invention (Claim 1)
According to claim 2), the fluctuation of the generator characteristics due to the fluctuation of the inductance of the field winding depending on the rotation speed of the rotor and the field current required for the rated current is determined by the internal voltage of the automatic voltage regulator. A stable voltage control system can be configured by the same control method as before by correcting by calculation, and it is possible to provide an automatic voltage regulator of a synchronous generator that can supply a stable voltage to a load at an arbitrary rotation speed. it can.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of one embodiment of the present invention.

FIG. 2 is a circuit diagram of another embodiment of the present invention.

FIG. 3 is a circuit diagram of a conventional automatic voltage regulator of a synchronous generator.

FIG. 4 is a saturation characteristic diagram of a field winding of a generator and an exciter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Synchronous generator or brushless synchronous generator, 2 ... Diode, 3 ... DC power supply, 4 ... Switching element, 5 ... Voltage detector, 6 ... Voltage command signal generator, 7 ... Operational amplifier,
8 ... pulse width modulator, 9 ... motor, 10 ... load, 20 ...
Rotation speed detector, 21... First correction signal output device, 22.
Multiplier, 23: second correction signal output device.

Claims (2)

[Claims] 1. A switching element connected in series to a field winding of a synchronous generator for adjusting a field voltage by a switching operation, and supplying a DC voltage to a series circuit including the field winding and the switching element. A DC power supply, a diode connected in parallel to the field winding and having a cathode terminal connected to a positive output terminal of the DC power supply, a voltage detector for detecting a terminal voltage of the synchronous generator, A voltage command signal generator that outputs a command signal, performs a control operation based on the output signals of the voltage detector and the voltage command signal generator, compensates for variations in generator characteristics due to variations in load impedance, An operational amplifier that outputs a control signal for keeping the voltage of the synchronous generator at a desired voltage, a rotational speed detector that detects the rotational speed of the synchronous generator, and a signal from the rotational speed detector. A first correction signal output device for outputting a correction signal for correcting a variation in inductance due to saturation of the field winding based on the output signal of the first correction signal output device and an output signal of the operational amplifier; And a pulse width modulator that outputs a pulse voltage in an on-period proportional to the output signal of the multiplier and performs a switching operation of the switching element, even when the rotation speed of the synchronous generator changes. An automatic voltage regulator for a synchronous generator, characterized in that it is configured to correct a variation in inductance due to saturation of a field winding due to saturation characteristics and to perform stable voltage control. 2. The automatic voltage regulator of a synchronous generator according to claim 1, wherein a brushless synchronous generator is used instead of the synchronous generator, and a field winding of the exciter is generated based on an output signal of the rotation speed detector. A second correction signal output device for outputting a correction signal for correcting a variation in inductance due to line saturation; the multiplier includes an output signal of the operational amplifier, an output signal of the first correction signal output device, and a second correction signal; By multiplying the output signal of the output unit, even if the rotation speed of the brushless synchronous generator changes, the fluctuation of the inductance due to the saturation of each field winding due to the saturation characteristics of the synchronous generator and the exciter is corrected and stabilized. An automatic voltage regulator for a synchronous generator, characterized in that the automatic voltage regulator is configured to be able to perform various voltage controls.