JP2005304181A - Automatic voltage regulator of synchronous generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic voltage regulator of a synchronous generator with a low cost by space saving even if the field winding resistance value of a brushless synchronous generator or a synchronous generator to be combined with the automatic voltage regulator is different in the generator. <P>SOLUTION: The automatic voltage regulator of the synchronous generator calculates the maximum field current from the field winding resistance value of the synchronous generator and the voltage value of a dc exciting power supply, sets a ratio obtained by dividing the allowable current value capable of supplying a field voltage to a switching element for operating a chopper by the maximum field current, as the limit value of a field on duty. Thus, even if the generator having a small field resistance or a dc exciting power supply having a high voltage is combined, it prevents the overcurrent from flowing to a field switching element at the full forcing, such as a load application. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an automatic voltage regulator that automatically controls an output voltage of a synchronous generator or a brushless synchronous generator to a desired voltage.

  Conventional automatic voltage regulators for synchronous generators are disclosed in, for example, Patent Document 1 or Patent Document 2. An example of the prior art will be described with reference to FIG. In the figure, 1 is a brushless synchronous generator, 2 is a circuit breaker, 3 is a load, 4 is an automatic voltage regulator, and 5 is a DC power source. The automatic voltage regulator 4 includes a freewheeling diode 6, a chopper device 7, a voltage detector 8, a voltage command signal generator 9, a subtracter 10, an operational amplifier 11, and a pulse generator 12. The chopper device 7 includes a switching element 13 such as a transistor and a drive circuit 14, for example. The voltage command signal generator 9, the subtractor 10, the operational amplifier 11, and the pulse generator 12 are realized by, for example, a microcomputer and software.

In the conventional automatic voltage regulator, the brushless synchronous generator 1 supplies power to the load 3 through the circuit breaker 2 while the output voltage is controlled to be constant by the automatic voltage regulator 4. Voltage detector 8 detects the output voltage of the brushless synchronous generator 1, and outputs a detection signal V _g. The voltage command signal generator 9 outputs a command signal V _g ^* for controlling the output voltage of the generator to a desired voltage. The subtractor 10 calculates (V _g ^* −V _g ) and outputs an error signal ΔV _g . Operational amplifier 11 performs, for example, PID control operation of the error signal [Delta] V _g as inputs, outputs field voltage operation signal Vf ^* for keeping the output voltage of the generator even when the impedance of the load 3 varies the desired voltage To do. The pulse generator 12 outputs a pulse signal V _p of the ON width proportional to Vf ^* 7 at a constant frequency. ON width of the pulse signal _{V p} is, Vf ^* maximum value ^Vf *, a 100% max. Drive circuit 14 OFF drives the switching element 13 based on the pulse signal V _p. The switching element 13 chopper-operates a DC voltage applied from the DC power source 5 to the field winding of the AC generator 1a. The freewheeling diode 6 recirculates the field current flowing in the field winding of the brushless synchronous generator 1 during the period when the switching element 13 is off.

In the configuration as described above, the automatic voltage regulator 4 automatically adjusts the application amount of the field voltage even when the output voltage of the brushless synchronous generator 1 fluctuates due to the fluctuation of the load amount of the load 3, and brushless synchronization. It operates to control the output voltage of the generator 1 to a desired voltage set by the voltage command signal generator 9.
Japanese Patent No. 2536621 Patent No. 2680055

  In FIG. 6, for example, when the breaker 2 is closed during the no-load operation of the brushless synchronous generator 1, current suddenly flows to the load 3, so the output voltage of the generator decreases. As soon as the automatic voltage regulator 4 detects a decrease in the output voltage of the generator, the ON period of the switching element 13 is expanded and the field current of the generator is increased to quickly recover the output voltage of the generator to a desired voltage value. It works to let you. Thereafter, as the output voltage of the generator returns to a desired voltage value again, the ON period of the switching element 13 is reduced, and finally, the switching element 13 converges to the optimal ON period according to the load amount and becomes a stable state.

  In such an automatic voltage adjustment operation, the maximum current that may flow through the field winding of the generator is such that the switching element 13 is fully turned on and the voltage of the DC power supply 5 is continuously applied to the field winding. The amount is obtained by dividing the voltage of the DC power source 5 by the resistance value of the field winding of the brushless synchronous generator. Therefore, when the automatic voltage regulator 4 is manufactured, it is necessary to select the switching element 13 that is not damaged even when such a maximum field current flows.

  However, when the generator combined with the automatic voltage regulator is not one type, the resistance value of the field winding of the generator is not always constant. When combined with a generator having a resistance value smaller than the assumed resistance value, there is a possibility that a current larger than the allowable current flows through the switching element 13 temporarily. Therefore, the automatic voltage regulator that must be combined with many types of generators must select the allowable current of the switching element 13 in advance assuming a generator with the smallest field winding resistance, and so on. Even a generator that does not require a large allowable current must be an automatic voltage regulator that employs an expensive and large switching element.

  Moreover, it is desirable that the output voltage of the DC power supply 5 is always the same voltage value. However, the output voltage value of the combined DC power supply is limited to several voltage values depending on the specifications, and is the most necessary voltage for the automatic voltage regulator. In some cases, a close voltage must be selected. If the selected DC power supply voltage is higher than the voltage required for the automatic voltage regulator, the maximum current flowing in the field winding of the generator exceeds the allowable current of the switching element 13, which There is a risk of damage.

  The present invention has been made to cope with the above situation, and the problem is that the field winding resistance value of the synchronous generator combined with the automatic voltage regulator varies depending on the generator, or the output voltage value of the combined DC power supply. The present invention is to provide a low-cost and space-saving automatic voltage regulator for a synchronous generator that can employ a low-priced and small-sized switching element with a small allowable current even when the voltage varies depending on the DC power supply.

  In order to achieve the above object, an automatic voltage regulator for a synchronous generator according to claim 1 is a chopper device for supplying a DC power supply voltage to a field winding of a synchronous generator or a brushless synchronous generator by chopper operation. A reflux diode that circulates the current flowing in the field winding, a voltage detector that detects the output voltage of the generator, and a voltage that outputs a voltage command signal for controlling the output voltage of the generator to a desired voltage A command signal generator, a subtractor for outputting an error signal between the voltage command signal and the voltage detection signal, and the chopper necessary for performing a control operation based on the error signal and maintaining the output voltage of the generator at a desired voltage. An operational amplifier that outputs a control signal indicating the ON period of the device, a field resistance value setting device for the generator, an output voltage value setting device for the DC power supply, and a maximum field value for setting a desired maximum field current value Current value setter and A maximum control signal calculator for calculating the maximum value of the control signal from the field resistance value, the DC power supply voltage value and the maximum field current value, and a limiter for limiting the control signal based on a signal from the maximum control signal calculator And a pulse generator that outputs a pulse signal having a constant frequency based on a control signal output from the limiter as a drive signal of the chopper device, and the maximum control signal calculator is a field resistance value of the generator. And calculating the maximum current that can flow in the field winding from the voltage value of the DC power source, and further outputting the signal obtained by dividing the current value of the maximum field current value setting device by the current value. In this case, the current is limited so as not to flow more than a desired current value.

  The automatic voltage regulator for a synchronous generator according to claim 2 is the automatic voltage regulator for a synchronous generator according to claim 1, wherein a field voltage detector and a field are used instead of the field resistance value setter of the generator. A current detector is provided, and a field resistance calculator for calculating a resistance value of the field winding from the field voltage and field current detected by the current detector is provided.

  The automatic voltage regulator for the synchronous generator according to claim 3 is the automatic voltage regulator for the synchronous generator according to claim 1 or 2, wherein the voltage detection of the DC power supply is performed instead of the output voltage value setter of the DC power supply. It is characterized by providing a vessel.

  According to the present invention, even when combined with a synchronous generator or a brushless synchronous generator having various field winding resistances, or even when the voltage value of the DC power source supplying power to the field winding of the synchronous generator changes. The increase in field current due to load fluctuations can be limited within the allowable current of the switching element in the chopper device, eliminating the need for an expensive and large switching element with a large allowable current value. Automatic voltage regulator of the machine can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit configuration diagram of an automatic voltage regulator for a synchronous generator according to a first embodiment of the present invention.
As shown in FIG. 1, the present embodiment is different from the conventional automatic voltage regulator of the synchronous generator of FIG. 6 described above in that the field resistance value setter 15 of the generator and the output voltage of the DC power supply A value setter 16, a maximum field current value setter 17 for setting a desired maximum field current value, a maximum control signal calculator 18, and a limiter 19 are provided. Since they are the same, the same components are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 1, a voltage command signal generator 9, a subtracter 10, an operational amplifier 11, a pulse generator 12, a field resistance value setter 15, an output voltage value setter 16 of a DC power supply, and a maximum field current value setter 17. The maximum control signal calculator 18 and the controller 19 are realized by a microcomputer and software, for example.

Next, the operation of the main components of the present embodiment will be described.
Here, the brushless synchronous generator 1, the circuit breaker 2, the load 3, the DC power source 5, the freewheeling diode 6, the chopper device 7, the voltage detector 8, the voltage command signal generator 9, the subtractor 10, the operational amplifier 11, and the drive circuit 14. The operation of the switching element 13 is the same as that of the automatic voltage regulator of the conventional synchronous generator shown in FIG.

The generator field resistance value setter 15 outputs a signal Rf corresponding to the set field resistance value of the generator. Output voltage setter 16 of the DC power source outputs a signal V _s corresponding to the output voltage value of the DC power source 5 which is set. The maximum field current value setting unit 17 outputs a signal If ^* , max corresponding to the set desired maximum field current value. For If ^* , max, the maximum current value that can flow without damaging the switching element 13 is selected. The maximum control signal calculator 18 calculates the equation (1) from the signals Rf, V _s , If ^* , max and the maximum value Vf ^* , max of the output signal Vf ^* of the operational amplifier 11, and the calculation result Vf ^* and limit are output.

Vf ^* , limit = If ^* , max × (Rf / V _s ) × Vf ^* , max (1)
The limiter 19 outputs Vf ^** with Vf ^* limited as shown in FIG. 2 based on Vf ^* and limit. As shown in FIG. 3, the pulse generator 12 outputs a pulse signal V _p having a constant frequency with an ON width proportional to Vf ^** to the drive circuit 14. ON width of the V _p is the maximum value ^Vf ** of ^{Vf **} possible values, becomes 100% when the max, ^Vf * as shown in FIG. 2, restricted ^{Vf **} is input by the limit In this case, the ON width is limited to V _p and limit, and the ON width is not further increased.

Since the present embodiment is configured as described above, the maximum current flowing in the field winding of the brushless synchronous generator 1 does not exceed If ^* , max set by the maximum field current value setting unit 17. Therefore, even when the automatic voltage regulator is combined with a generator having a lower field winding resistance than expected or a DC power source having a higher voltage than assumed, the switching element of the chopper device 7 is used. In FIG. 13, an allowable current of If ^* , max or less can be adopted, and an automatic voltage regulator can be configured with inexpensive and small components.

FIG. 4 is a circuit configuration diagram of an automatic voltage regulator for a synchronous generator according to a second embodiment of the present invention.
As shown in the figure, the configuration in which the present embodiment is different from the automatic voltage regulator of the synchronous generator of the first embodiment of FIG. 1 is that the field of the generator is used instead of the field resistance value setter 15 of the generator. The magnetic voltage detector 20, the generator field current detector 21, and the field resistance calculator 22 are provided. Since the other components are the same, the same reference numerals are given to the same components. Therefore, duplicate explanation is omitted.

  Here, the voltage command signal generator 9, the subtracter 10, the operational amplifier 11, the pulse generator 12, the output voltage value setter 16 of the DC power supply, the maximum field current value setter 17, and the maximum control signal calculator 18 are limited. The device 19 and the field resistance calculator 22 can be realized by a microcomputer and software, for example.

Next, the operation of the main components of the present embodiment will be described.
Here, the brushless synchronous generator 1, the circuit breaker 2, the load 3, the DC power source 5, the freewheeling diode 6, the chopper device 7, the voltage detector 8, the voltage command signal generator 9, the subtractor 10, the operational amplifier 11, and the drive circuit 14, the switching element 13, the output voltage value setter 16 of the DC power supply, the maximum field current value setter 17 and the maximum control signal calculator 18 are the automatic voltage adjustment of the synchronous generator of the first embodiment of FIG. Since the same action as that in the vessel is performed, the description thereof is omitted.

  The generator field voltage detector 20 detects the generator field voltage and outputs a signal Vfd corresponding thereto. The generator field current detector 21 detects the generator field current and outputs a signal Ifd corresponding thereto. The field resistance calculator 22 calculates (Vfd / Ifd) from the signals Vfd and Ifd and outputs the calculation result to the maximum control signal calculator 18 as a signal Rf.

  Since the present embodiment is configured as described above, it is possible to automatically detect the field resistance without setting the field resistance of the brushless synchronous generator 1 in advance, and the first embodiment of FIG. The same effect can be obtained, and the setting work of the automatic voltage regulator can be saved.

FIG. 5 is a circuit configuration diagram of an automatic voltage regulator for a synchronous generator according to a third embodiment of the present invention.
As shown in FIG. 5, the present embodiment is different from the automatic voltage regulator of the synchronous generator of the second embodiment of FIG. 4 in that the voltage of the DC power supply is used instead of the output voltage value setter 16 of the DC power supply. The other components are the same because the detector 23 is provided, and the same components are denoted by the same reference numerals and the description thereof is omitted.

  Here, the voltage command signal generator 9, the subtracter 10, the operational amplifier 11, the pulse generator 12, the maximum field current value setter 17, the maximum control signal calculator 18, the limiter 19, and the field resistance calculator 22 are For example, it is realized by a microcomputer and software.

Next, the operation of the main components of the present embodiment will be described.
Brushless synchronous generator 1, circuit breaker 2, load 3, DC power supply 5, freewheeling diode 6, chopper device 7, voltage detector 8, voltage command signal generator 9, subtractor 10, operational amplifier 11, drive circuit 14, switching The operation of the element 13, the maximum field current value setter 17, the maximum control signal calculator 18, the field voltage detector 20, the field current detector 21, and the field resistance calculator 22 has been described in the embodiment described above ( Since the same operation as that in the automatic voltage regulator according to claim 2 is performed, a duplicate description is omitted. The voltage detector 23 of the DC power supply detects the voltage of the DC power supply 5 and outputs a corresponding signal to the maximum control signal calculator 18 as Vs.

  Since the present embodiment is configured as described above, the voltage can be automatically detected without setting the voltage value of the DC power supply 5 in advance, and the same effect as the second embodiment of FIG. 4 can be obtained. At the same time, the setting work of the automatic voltage regulator can be saved.

The circuit block diagram of the 1st Embodiment of this invention. The figure which shows the input-output characteristic of the limiter of FIG. The figure which shows the input-output characteristic of the pulse generator of FIG. The circuit block diagram of the 2nd Embodiment of this invention. The circuit block diagram of the 3rd Embodiment of this invention. The circuit block diagram of the conventional automatic voltage regulator. The figure which shows the input-output characteristic of the pulse generator of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brushless synchronous generator, 2 ... Circuit breaker, 3 ... Load, 4 ... Automatic voltage regulator, 5 ... DC power supply, 6 ... Freewheeling diode, 7 ... Chopper device, 8 ... Voltage detector, 9 ... Voltage command signal generation 10 ... subtractor 11 ... operational amplifier 12 ... pulse generator 13 ... switching element 14 ... drive circuit 15 ... field resistance value setter 16 ... DC power supply output voltage value setter 17 ... Maximum field current value setting unit, 18 ... maximum control signal calculator, 19 ... limiter, 20 ... field voltage detector, 21 ... field current detector, 22 ... field resistance calculator, 23 ... DC power supply Voltage detector.

Claims (3)

  Chopper device that supplies DC power supply voltage to the field winding of a synchronous generator or brushless synchronous generator by chopper operation, a free-wheeling diode that circulates the current flowing in the field winding, and the output voltage of the generator A voltage detector that outputs, a voltage command signal generator that outputs a voltage command signal for controlling the output voltage of the generator to a desired voltage, a subtractor that outputs an error signal between the voltage command signal and the voltage detection signal, An operational amplifier that performs control calculation based on the error signal and outputs a control signal indicating the ON period of the chopper device necessary for maintaining the output voltage of the generator at a desired voltage, and setting the field resistance value of the generator The output voltage value setting device of the DC power supply, the maximum field current value setting device for setting a desired maximum field current value, the field resistance value, the DC power supply voltage value, and the maximum field current value. Control signal Maximum control signal calculator that calculates a large value, limiter that limits the control signal based on the signal from the maximum control signal calculator, and a pulse with a constant frequency in the ON period based on the control signal output from the limiter It consists of a pulse generator that outputs a signal as a drive signal of the chopper device, the maximum control signal calculator calculates the maximum current that can flow to the field winding from the field resistance value of the generator and the voltage value of the DC power supply, Further, by outputting a signal obtained by dividing the current value of the maximum field current value setting device by the current value, it is limited so that a current exceeding a desired current value does not flow through the field winding. Automatic voltage regulator for synchronous generator.   2. The automatic voltage regulator for a synchronous generator according to claim 1, wherein a field voltage detector and a field current detector are provided in place of the field resistance value setter of the generator, and the field voltage and field detected by these are detected. An automatic voltage regulator for a synchronous generator, comprising a field resistance calculator for calculating a resistance value of a field winding from a magnetic current. 3. The automatic voltage regulator for a synchronous generator according to claim 1, further comprising a voltage detector for the DC power supply instead of the output voltage value setter for the DC power supply. vessel.

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