Control device and control method for automatic voltage regulator

Abstract

To control the automatic voltage regulator to perform optimal startup control while suppressing overshoot during generator startup. [Solution] The present invention is a control device for an automatic voltage regulator, comprising: a switch that generates a switching signal according to the voltage detection level in order to switch the control gain of the automatic voltage regulator between the initial startup and after setting; and a gain setter that generates a gain signal that sets the type and number of control gains based on the switching signal and provides the gain signal to the automatic voltage regulator.

Description

Technical Field

[0001] The present invention relates to a control technique for an automatic voltage regulator, and more particularly to a control device and a control method for controlling an automatic voltage regulator so as to suppress overshoot at the time of starting a generator and enable optimal starting control.

Background Art

[0002] Generally, an automatic voltage regulator is installed in an excitation device of a synchronous machine, and by the function of maintaining the voltage of the synchronous machine constant during steady operation, it maintains the voltage when the load changes, adjusts the reactive power, and improves the dynamic stability. It is widely used for suppressing the voltage rise at the time of load interruption and improving the transient stability by the function of quickly restoring the voltage when the voltage suddenly changes.

[0003] For this purpose, it is necessary for the automatic voltage regulator to have a small control deviation, sufficient responsiveness, and sufficient stability as a control system.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a separately excited synchronous generator using its own generator output as an excitation power source, during a period when the generator voltage output is low, the excitation power source voltage is also low, so the control response becomes slower and the overshoot at the time of starting becomes larger compared to the rated voltage.

[0006] Although it is possible to suppress overshoot by controlling to increase the voltage reference of the voltage regulator in a ramp shape to gently increase the voltage and by setting a longer set time, this delays the starting time of the generator voltage.

[0007] Furthermore, in the case of shunt-wound synchronous generators, they may start using the induced voltage due to residual magnetic flux as the power source. However, to ensure reliable voltage startup, an external DC power supply voltage is usually applied. Depending on the level of the initial excitation voltage, there may be a discrepancy between the voltage reference of the voltage regulator at startup and the generator output voltage, which can lead to overshoot or undershoot of the generator output voltage depending on the control response at that time.

[0008] In light of the above circumstances, the problem that the present invention aims to solve is to provide a control device and a control method for controlling an automatic voltage regulator so as to perform optimal startup control that suppresses overshoot when starting up a generator. [Means for solving the problem]

[0009] A first aspect of the present invention is a control device for an automatic voltage regulator, comprising: a switch that generates a switching signal according to a voltage detection level in order to switch the control gain of the automatic voltage regulator between the initial startup phase and after setting; and a gain setter that generates a gain signal that sets the type and number of control gains based on the switching signal and provides the gain signal to the automatic voltage regulator.

[0010] A second aspect of the present invention is a control device for an automatic voltage regulator, comprising a gain setter that generates a control gain signal associated with the voltage detection level of a generator and provides the control gain signal to the automatic voltage regulator in order to change the control gain of the automatic voltage regulator in relation to the output voltage level of the generator.

[0011] A third aspect of the present invention is a control device for an automatic voltage regulator, comprising a gain setter that generates a control gain signal associated with the voltage level of an exciter and provides the control gain signal to the automatic voltage regulator in order to change the control gain of the automatic voltage regulator in relation to the voltage level of the exciter.

[0012] A fourth aspect of the present invention is a control device for an automatic voltage regulator, comprising a gain setter that generates a control gain signal associated with the voltage frequency of a generator and provides the control gain signal to the automatic voltage regulator in order to change the control gain of the automatic voltage regulator in relation to the output voltage frequency of the generator or the rotational speed of the generator.

[0013] A fifth aspect of the present invention is a control method for an automatic voltage regulator, comprising: generating a switching signal according to a voltage detection level in order to switch the control gain of the automatic voltage regulator between the initial startup phase and after setting; generating a gain signal that sets the type and number of control gains based on the switching signal; and providing the gain signal to the automatic voltage regulator.

[0014] A sixth aspect of the present invention is a control method for an automatic voltage regulator, wherein a control gain signal is generated in relation to the voltage detection level of a generator, and the control gain signal is provided to the automatic voltage regulator, in order to change the control gain of the automatic voltage regulator in relation to the output voltage level of the generator.

[0015] A seventh aspect of the present invention is a control method for an automatic voltage regulator, wherein a control gain signal is generated in relation to the voltage level of an exciter, and the control gain signal is provided to the automatic voltage regulator, in order to change the control gain of the automatic voltage regulator in relation to the voltage level of the exciter.

[0016] An eighth aspect of the present invention is a control method for an automatic voltage regulator, comprising generating a control gain signal associated with the voltage frequency of a generator and providing the control gain signal to the automatic voltage regulator in order to change the control gain of the automatic voltage regulator in relation to the output voltage frequency of the generator or the rotational speed of the generator. [Effects of the Invention]

[0017] The control device and control method for an automatic voltage regulator of the present invention enable the automatic voltage regulator to perform optimal startup control with suppressed overshoot during generator startup. [Brief explanation of the drawing]

[0018] [Figure 1] FIG. 1 is a configuration diagram showing an application example of a control device to which a control method for an automatic voltage regulator according to a first embodiment of the present invention is applied. [Figure 2] FIG. 2 is a configuration diagram showing an application example of a control device to which a control method for an automatic voltage regulator according to a second embodiment of the present invention is applied. [Figure 3] FIG. 3 is a configuration diagram showing an application example of a control device to which a control method for an automatic voltage regulator according to a third embodiment of the present invention is applied. [Figure 4] FIG. 4 is a configuration diagram showing an application example of a control device to which a control method for an automatic voltage regulator according to a fourth embodiment of the present invention is applied.

MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual. In this specification and each figure, the same elements as those described in the already shown figures are denoted by the same reference numerals, and detailed descriptions and duplicate descriptions are omitted as appropriate.

[0020] (First Embodiment) FIG. 1 is a configuration diagram showing an application example of a control device to which a control method for an automatic voltage regulator according to a first embodiment of the present invention is applied.

[0021] The generator 32 illustrated in FIG. 1 is a synchronous generator (split winding), and converts rotational energy generated by a prime mover, for example, an engine 30, into electrical energy using the principle of electromagnetic induction to generate AC power and supply it to the power system 36.

[0022] The exciter 34 is a rotating machine directly connected coaxially with the generator 32 and supplies an exciting current to the field of the generator 32.

[0023] The automatic voltage regulator 20, indicated as AVR in the figure, is a control device (electronic circuit or software) that controls the excitation current of the generator 32 or the exciter 34 via the instrument transformer VT in order to keep the output voltage of the generator 32 constant.

[0024] The control device 10 according to this embodiment includes a switch 12 and a gain setter 14 for controlling the automatic voltage regulator 20.

[0025] The switch 12 generates a switching signal a according to the voltage detection level and provides it to the gain setter 14 in order to switch the control gain of the automatic voltage regulator 20 between the initial startup and after setting.

[0026] The gain setter 14 generates a gain signal b that sets the type and number of control gains based on the switching signal a, and provides the gain signal b to the automatic voltage regulator 20.

[0027] As a result, the automatic voltage regulator 20 is controlled based on the gain signal b, and consequently, as shown in inset A(a) in Figure 1, the automatic voltage regulator 20 switches the control gain during startup and rated operation between gain 1 and gain 2, thereby enabling optimal startup control that suppresses voltage overshoot of the generator 32, as shown in inset A(b).

[0028] (Second embodiment) Figure 2 is a configuration diagram showing an example of a control device to which the control method for an automatic voltage regulator according to the second embodiment of the present invention is applied.

[0029] The differences from Figure 1 will be explained below.

[0030] The control device 10A according to this embodiment includes a gain setter 14A for controlling the automatic voltage regulator 20.

[0031] The gain setter 14A generates a control gain signal c associated with the voltage detection level of the generator 32, and provides the control gain signal c to the automatic voltage regulator 20, in order to change the control gain of the automatic voltage regulator 20 in relation to the output voltage level of the generator 32.

[0032] As a result, the automatic voltage regulator 20 is controlled based on the control gain signal c, and as a result, the automatic voltage regulator 20 can switch the control gain during startup and rated operation between gain 1 and gain 2, as shown in inset B(a) in Figure 2, thereby enabling optimal startup control that suppresses voltage overshoot of the generator 32, as shown in inset B(b).

[0033] (Third embodiment) Figure 3 is a configuration diagram showing an example of a control device to which the control method for an automatic voltage regulator according to the third embodiment of the present invention is applied.

[0034] The differences from Figure 1 will be explained below.

[0035] The control device 10B according to this embodiment includes a gain setter 14B for controlling the automatic voltage regulator 20.

[0036] The gain setter 14B generates a control gain signal d associated with the voltage level of the exciter 34 and provides the control gain signal d to the automatic voltage regulator 20 in order to change the control gain of the automatic voltage regulator 20 in relation to the voltage level of the exciter 34.

[0037] As a result, the automatic voltage regulator 20 is controlled based on the control gain signal d, and consequently, as shown in inset C(b) in Figure 3, the automatic voltage regulator 20 changes the control gain at startup and rated power to gain 3 and gain 2, respectively, according to the excitation voltage of the exciter 34, as shown in inset C(a), thereby enabling optimal startup control that suppresses voltage overshoot of the generator 32, as shown in inset C(c).

[0038] Furthermore, the control device 10B according to this embodiment may also include additional functions of the control device 10A.

[0039] (Fourth embodiment) Figure 4 is a configuration diagram showing an example of a control device to which the control method for an automatic voltage regulator according to the fourth embodiment of the present invention is applied.

[0040] The differences from Figure 1 will be explained below.

[0041] The control device 10C according to this embodiment includes a gain setter 14C for controlling the automatic voltage regulator 20.

[0042] The gain setter 14C generates a control gain signal e associated with the voltage frequency of the generator 32 and provides the control gain signal e to the automatic voltage regulator 20 in order to change the control gain of the automatic voltage regulator 20 in relation to the output voltage frequency of the generator 32 or the rotational speed of the generator 32. Alternatively, the rotational speed of the engine 30 may be used instead of the output voltage frequency of the generator 32.

[0043] As a result, the automatic voltage regulator 20 is controlled based on the control gain signal e, and consequently, as shown in inset D(b) in Figure 4, the automatic voltage regulator 20 changes the control gain at startup and rated power as gain 1 and gain 2, as shown in inset D(a), according to the voltage frequency of the generator 32, thereby enabling optimal startup control that suppresses voltage overshoot of the generator 32, as shown in inset D(c).

[0044] As described above, with a control device to which the control method for the automatic voltage regulator according to each of the above embodiments is applied, the overshoot during voltage startup of the generator 32 can be suppressed by appropriately switching the control gain in response to the dynamic movement of the generator 32 during voltage startup.

[0045] Furthermore, by changing the associated voltage from that of the generator 32 to that of the exciter 34, it is possible to respond to changes in external factors such as initial excitation.

[0046] Furthermore, a similar effect can be obtained by detecting the rotational speed of the generator 32, in addition to the voltage level.

[0047] By switching the control gain in relation to the voltage level in this way, it becomes possible to achieve situation-specific response control, such as during startup or at rated operation.

[0048] The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to this configuration. Within the scope of the invented technical idea of ​​the claims, a person skilled in the art can conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0049] 10, 10A, 10B, 10C control devices 12 Switches 14, 14A, 14B, 14C Gain Setter 20 Automatic Voltage Regulator 30 Engine 32 Generators 34 Exciter 36 Power system a. Switching signal b Gain signal c Control gain signal d Control gain signal e Control gain signal VT Instrument Transformer

Claims

1. A control device for an automatic voltage regulator, A switch that generates a switching signal according to the voltage detection level in order to switch the control gain of the aforementioned automatic voltage regulator between the initial startup and after setting, A gain setter generates a gain signal that sets the type and number of control gains based on the switching signal, and provides the gain signal to the automatic voltage regulator. A control device equipped with the following features.

2. A control device for an automatic voltage regulator, A gain setter generates a control gain signal associated with the voltage detection level of the generator, and provides the control gain signal to the automatic voltage regulator, in order to change the control gain of the automatic voltage regulator in relation to the output voltage level of the generator. A control device equipped with the following features.

3. A control device for an automatic voltage regulator, A gain setter generates a control gain signal associated with the voltage level of the exciter, and provides the control gain signal to the automatic voltage regulator, in order to change the control gain of the automatic voltage regulator in relation to the voltage level of the exciter. A control device equipped with the following features.

4. A control device for an automatic voltage regulator, A gain setter generates a control gain signal associated with the voltage frequency of the generator and provides the control gain signal to the automatic voltage regulator in order to change the control gain of the automatic voltage regulator in relation to the output voltage frequency of the generator or the rotational speed of the generator. A control device equipped with the following features.

5. A control method for an automatic voltage regulator, In order to switch the control gain of the aforementioned automatic voltage regulator between the initial startup phase and after it has been set, a switching signal is generated according to the voltage detection level. A control method comprising generating a gain signal that sets the type and number of control gains based on the switching signal, and providing the gain signal to the automatic voltage regulator.

6. A control method for an automatic voltage regulator, A control method comprising generating a control gain signal associated with the voltage detection level of the generator, and providing the control gain signal to the automatic voltage regulator, in order to change the control gain of the automatic voltage regulator in relation to the output voltage level of the generator.

7. A control method for an automatic voltage regulator, A control method comprising: generating a control gain signal associated with the voltage level of the exciter, and providing the control gain signal to the automatic voltage regulator, in order to change the control gain of the automatic voltage regulator in relation to the voltage level of the exciter.

8. A control method for an automatic voltage regulator, A control method comprising generating a control gain signal associated with the voltage frequency of the generator and providing the control gain signal to the automatic voltage regulator in order to change the control gain of the automatic voltage regulator in relation to the output voltage frequency of the generator or the rotational speed of the generator.

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