Voltage fluctuation suppression device for AC generators

Abstract

To suppress a voltage fluctuation rate with respect to a rated voltage in an AC power generator.SOLUTION: A voltage fluctuation suppressing device is installed in an AC power generator, and suppresses a voltage fluctuation by performing excitation control based on an output voltage. The voltage suppressing device includes a load current detection unit that detects a load current of each output terminal, an in-use output terminal identification unit that identifies an output terminal which is being used on the basis of detection performed by the load current detection unit, an inter-terminal voltage detection unit that detects a voltage between terminals including the output terminal identified by the in-use output terminal identification unit, and an excitation control unit that performs excitation control at an output voltage obtained from the inter-terminal voltage detected by the inter-terminal voltage detection unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a voltage fluctuation suppressor for an AC generator. [Background technology]

[0002] There are known AC generators with three-phase (R, S, and T) output terminals and single-phase (U and V) output terminals. Also known are those equipped with an automatic voltage regulator (AVR) that performs excitation control so that the output voltage reaches a target voltage value in order to keep the output voltage of the AC generator constant (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-239487 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional automatic voltage regulators regulate output voltage by measuring the voltage between specific output terminals and controlling the excitation current so that the measured output voltage becomes the target voltage. However, when control is performed using a conventional automatic voltage regulator, uneven loads can cause the difference in terminal voltage to increase, resulting in problems such as a large fluctuation rate of the three-phase average output voltage (three-phase Σ voltage regulation rate) and a large single-phase voltage regulation rate (single-phase voltage regulation rate) compared to the rated voltage.

[0005] Furthermore, when controlling an AC generator using a conventional automatic voltage regulator, if three-phase or single-phase is used alone, a mismatch between the output terminal to which the load is connected and the terminal at which the output voltage is measured can cause the output voltage between the terminals to deviate from the target voltage, resulting in a problem of worsening voltage regulation.

[0006] The present invention has been proposed to address these problems. Specifically, the objectives of the present invention are to suppress the voltage regulation rate relative to the rated voltage in an AC generator, to be able to suppress the voltage regulation rate in both three-phase and single-phase when three-phase and single-phase are used simultaneously, and to suppress deterioration of the voltage regulation rate due to mismatch between the terminal to which the load is connected and the terminal at which the output voltage is measured when three-phase or single-phase is used alone. [Means for solving the problem]

[0007] In order to solve such problems, the present invention has the following configuration. A voltage fluctuation suppression device is equipped to an AC generator and suppresses voltage fluctuations by excitation control based on output voltage, and includes a load current detection unit that detects the load current at each output terminal, a used output terminal identification unit that identifies the output terminal that is being used based on the detection by the load current detection unit, an inter-terminal voltage detection unit that detects the inter-terminal voltage including the output terminal identified by the used output terminal identification unit, and an excitation control unit that performs excitation control using an output voltage determined from the inter-terminal voltage detected by the inter-terminal voltage detection unit. [Effects of the Invention]

[0008] According to the present invention having such characteristics, it is possible to suppress the voltage regulation rate relative to the rated voltage, and when three-phase output terminals and single-phase output terminals are used simultaneously, excitation control is performed by an output voltage based on the terminal-to-terminal voltage of the three-phase output terminals and the terminal-to-terminal voltage of the single-phase output terminals, making it possible to control both the three-phase output and the single-phase output with suppressed voltage regulation rate.

[0009] Furthermore, when a three-phase output terminal or a single-phase output terminal is used alone, the terminal being used is identified, the inter-terminal voltage is detected, and excitation control is performed using the output voltage calculated from the detected inter-terminal voltage, thereby preventing a deterioration in the voltage regulation rate due to a mismatch between the output terminal being used and the detected terminal. [Brief explanation of the drawings]

[0010] [Figure 1]1 is an explanatory diagram showing an example of the configuration of a voltage fluctuation suppressing device for an AC generator according to an embodiment of the present invention; [Figure 2] FIG. 4 is an explanatory diagram showing another example of the configuration of a voltage fluctuation suppressing device for an AC generator according to an embodiment of the present invention. [Figure 3] FIG. 4 is an explanatory diagram showing an example of a calculation formula table for an output voltage in an output voltage calculation unit. [Figure 4] FIG. 4 is an explanatory diagram showing another example of the configuration of a voltage fluctuation suppressing device for an AC generator according to an embodiment of the present invention. [Figure 5] FIG. 10 is an explanatory diagram showing an example of a calculation formula table for an output voltage in another configuration example. [Figure 6] FIG. 2 is an explanatory diagram showing an example of a connection of an armature winding in an armature of an AC generator. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote parts with the same functions, and duplicated descriptions in each drawing will be omitted as appropriate.

[0012] 1, a voltage fluctuation suppression device 1 for an AC generator 10 (hereinafter simply referred to as a voltage fluctuation suppression device) is provided for the AC generator 10 and includes a control device 20 for suppressing fluctuations in the output voltage taken out from the output terminal 11A of the armature 11. The control device 20 includes at least a load current detection unit 21, an output terminal use specification unit 22, an inter-terminal voltage detection unit 23, and an excitation control unit 24 as calculation processing functions.

[0013] A load current detection unit 21 in the control device 20 detects a load current at an output terminal 11A of the armature 11. In the illustrated example, the armature 11 has three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) and single-phase output terminals (U-phase terminal, W-phase terminal), and wiring L connecting the armature winding of the armature 11 to each output terminal 11A. R ,L S ,L T ,L U ,L W Current detection section C R ,CS ,C T ,C U ,C W The load current is detected via the load current detector 21, and the detected load current is input to the load current detector 21.

[0014] In the illustrated example, the output terminals 11A of the armature 11 include an R-phase terminal, an S-phase terminal, a T-phase terminal, a U-phase terminal, and a W-phase terminal, but the embodiment of the present invention is not limited to this. The armature 11 may be one that configures three-phase output terminals, for example, with a Y-connection or a Δ-connection of the armature winding, and the individual single-phase output terminals (U-phase terminal, W-phase terminal) may be omitted, and the R-phase terminal, S-phase terminal, and T-phase terminal of a three-phase generator may be used as three-phase output terminals or as single-phase output terminals.

[0015] The used output terminal specifying unit 22 in the control device 20 specifies the output terminal 11A in which the load current is detected by the load current detecting unit 21. Specifically, R ,L S ,L T ,L U ,L W If load current is detected from all of the three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) and the single-phase output terminals (U-phase terminal, W-phase terminal), both are identified as used output terminals, and wiring L R ,L S ,L T ,L U ,L W If a load current is detected from only one of the above, the output terminal of the wiring from which the load current is detected is identified and set as the output terminal to be used.

[0016] The terminal voltage detection unit 23 in the control device 20 detects the voltage across the wiring L R ,L S ,L T ,L U ,L W Detection points P R ,P S ,P T ,P U ,P WAt this time, the inter-terminal voltage detection unit 23 detects the inter-terminal voltage including the used output terminal identified by the used output terminal identification unit 22.

[0017] In other words, when both the three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) and the single-phase output terminals (U-phase terminal, W-phase terminal) are specified as the output terminals to be used (when three-phase and single-phase terminals are used simultaneously), the terminal voltage V between RS, ST, TR, and UW R-S ,V S-T ,V T-R ,V U-W In addition, when only the three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) are identified as the output terminals in use (when only three phases are used), the terminal voltages V between RS, ST, and TR are detected. R-S ,V S-T ,V T-R When only the single-phase output terminals (U-phase terminal, W-phase terminal) are identified as the output terminals in use (when using only a single phase), the voltage V between the U and W terminals is U-W Detects only

[0018] The excitation control unit 24 in the control device 20 calculates the output voltage using only the voltage value of the inter-terminal voltage detected by the inter-terminal voltage detection unit 23, i.e., the inter-terminal voltage including the specified used output terminal, and performs excitation control so that this output voltage becomes the target voltage. In this way, the output voltage is calculated only from the inter-terminal voltage between the output terminals 11A that are actually used, and by controlling the excitation current flowing through the excitation coil 12 of the AC generator 10 based on this output voltage, it is possible to suppress voltage fluctuations in the output voltage.

[0019] Regarding the control content of the excitation control unit 24, the instantaneous value of the terminal voltage detected by the terminal voltage detection unit 23 may be used as the output voltage and control may be performed based on this, or the terminal voltage detected by the terminal voltage detection unit 23 may be calculated to determine the output voltage and control may be performed based on this.

[0020] When the instantaneous value is used as the output voltage, for example, the regulation rate with respect to the rated voltage is calculated as needed, and the target voltage is reset when the regulation rate exceeds a threshold. In this case, if both the three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) and the single-phase output terminals (U-phase terminal, W-phase terminal) are identified as the used output terminals, the target voltage is increased when the three-phase or single-phase regulation rate reaches its lower limit, and decreased when the three-phase or single-phase regulation rate reaches its upper limit. The target voltage is then increased and decreased a set number of times (several times) at set intervals (several seconds), and the output voltage is adjusted by PID control so that the three-phase regulation rate falls within an acceptable range (e.g., ±2.5%). In this case, it is preferable to set the threshold for the three-phase regulation rate within 2.5% and the threshold for the single-phase regulation rate within ±3.5%.

[0021] When the output voltage is calculated by calculation, as shown in Fig. 2, an output voltage calculation unit 25 is provided for the detected value of the inter-terminal voltage detection unit 23, and excitation control is performed based on the output voltage calculated by the output voltage calculation unit 25. In this case, the output voltage calculated by the output voltage calculation unit 25 includes the inter-terminal voltages of all the output terminals used.

[0022] In one example of output voltage calculation unit 25, when the output terminals to be used identified by output terminal identification unit 22 are three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) or single-phase output terminals (U-phase terminal, W-phase terminal), the average value of the detected inter-terminal voltages is set as the output voltage. When the output terminals to be used identified by output terminal identification unit 22 are three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) and single-phase output terminals (U-phase terminal, W-phase terminal) that are simultaneously used, the average value of the inter-terminal voltages of the three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) is set as a first average value (three-phase Σ voltage), and the average value of the inter-terminal voltages of the single-phase output terminals (U-phase terminal, W-phase terminal) and the first average value (three-phase Σ voltage) is set as a second average value, and the second average value is set as the output voltage.

[0023] An example of a calculation formula table for the output voltage in the output voltage calculation unit 25 is shown in FIG. 3. In this calculation formula table, No. 1 to No. 3 are cases where three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) are used independently, and one of the output terminals is specified as the used output terminal. In these cases, the inter-terminal voltage (V R-S ,V S-T ,V T-R ) the output voltage is the average value of the voltage between two terminals including one used output terminal.

[0024] In addition, No. 4 and No. 5 are cases where a single-phase output terminal (U-phase terminal, W-phase terminal) is used alone, and one of the output terminals is specified as the output terminal to be used. No. 15 is a case where a single-phase output terminal (U-phase terminal, W-phase terminal) is used alone, and two of the output terminals are specified as the output terminal to be used. In these cases, the terminal voltage V of the single-phase output terminal U-R is the output voltage.

[0025] No. 6 and No. 7 are cases where three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) are used independently, and two of the output terminals are specified as used output terminals. In these cases, the inter-terminal voltage of the two specified used output terminals is used as the output terminal. Also, No. 16 is a case where three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) are used independently, and all of the output terminals are specified as used output terminals. In this case, the inter-terminal voltage (V R-S ,V S-T ,V T-R ) average value ((V R-S +V S-T +V T-R ) / 3) is the output voltage.

[0026] Other numbers in the calculation formula table shown in FIG. 3 are for cases where three-phase and single-phase are used simultaneously. In this case, the average value of the inter-terminal voltages of the three-phase output terminals including the used output terminal is set as the first average value, the average value of this first average value and the inter-terminal voltages of the single-phase output terminal is set as the second average value, and this second average value is set as the output voltage.

[0027] Although an example is shown here in which the average value is calculated by the calculation process of the output voltage calculation unit 25, the calculation process of the output voltage calculation unit 25 is not limited to this. For example, the output voltage may be calculated by various calculation processes, such as calculating the median value other than the average value, or correcting and converting by multiplying by a specific coefficient.

[0028] 4 shows another example of the configuration of a voltage fluctuation suppressor according to an embodiment of the present invention. In the voltage fluctuation suppressor 1 shown in FIG. 4, an armature 11 has a neutral point, and a wiring L connected to a terminal (neutral point terminal) O for this neutral point. O Also, the detection point P of the inter-terminal voltage detection unit 23 O In this example, the detected inter-terminal voltage is the phase voltage (V) between the neutral terminal O and all output terminals (R-phase terminal, S-phase terminal, T-phase terminal, U-phase terminal, W-phase terminal). R-O ,V S-O ,V T-O ,V U-O ,V W-O ) is detected.

[0029] 5 shows an example of a calculation formula table for the output voltage in the output voltage calculation unit 25 of the example shown in FIG. 4. In this example, in all calculation formulas (No. 1 to No. 32), the output voltage is calculated using the phase voltage of the output terminal identified by the used output terminal identification unit 22. This makes it possible to reliably determine the output voltage corresponding to the load. The three-phase and single-phase usage situations of No. 1 to No. 32 in FIG. 5 correspond to the usage situations in FIG. 3.

[0030] In the calculation formula tables of Figures 3 and 5, No. 32 indicates a case where no current is detected in any of the output terminals (R-phase terminal, S-phase terminal, T-phase terminal, U-phase terminal, and W-phase terminal). In this case, assuming a malfunction in current detection, the output voltage is calculated assuming that current is flowing in all of the output terminals (all output terminals are in use).

[0031] As described above, the wiring of the armature windings in the armature 11 is not particularly limited. As an example, the wiring example shown in FIG. 6 can be used. In this example, an armature winding having single-phase output terminals (U-phase terminal, W-phase terminal) is connected to a three-phase connection of an armature winding having three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal). More specifically, the three-phase output terminals (R-phase terminal, S-phase terminal, T-phase terminal) are formed by the ends of three armature windings, the other ends of which are Y-connected to a neutral point O, and the single-phase output terminals (U-phase terminal, W-phase terminal) are formed by the other ends of two armature windings, the other ends of which are connected to the middle of two of the three armature windings. Note that the example shown in FIG. 6 is just one example, and the armature 11 may have any configuration as long as it can be used as a three-phase and a single-phase winding, either individually or simultaneously.

[0032] As described above, the voltage fluctuation suppressing device 1 according to the embodiment of the present invention detects the load current for each output terminal to identify the output terminal that is actually being used, calculates the output voltage from only the inter-terminal voltage of the output terminal that is being used, and performs excitation control so that this output voltage is in accordance with the target voltage. This makes it possible to control the output voltage to be optimal for the load connected to each output terminal, without performing any special detection-related connection switching or the like, regardless of whether three-phase independent use, single-phase independent use, or simultaneous three-phase and single-phase use is being used.

[0033] This makes it possible to suppress the voltage regulation rate relative to the rated voltage of the AC generator, and when three-phase output terminals and single-phase output terminals are used simultaneously, excitation control is performed using an output voltage based on the terminal-to-terminal voltage of the three-phase output terminals and the terminal-to-terminal voltage of the single-phase output terminals, making it possible to control both the three-phase output and the single-phase output with suppressed voltage regulation rate.

[0034] Furthermore, when a three-phase output terminal or a single-phase output terminal is used alone, the terminal being used is identified, the inter-terminal voltage is detected, and excitation control is performed using the output voltage calculated from the detected inter-terminal voltage, thereby preventing a deterioration in the voltage regulation rate due to a mismatch between the output terminal being used and the detected terminal.

[0035] Furthermore, the voltage fluctuation suppression device 1 according to an embodiment of the present invention not only suppresses the voltage fluctuation rate in a generator that can be used simultaneously as three-phase and single-phase, but also suppresses the voltage fluctuation rate by identifying the output terminal according to the load current even when a three-phase generator with only three-phase output terminals is used in single-phase operation.

[0036] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and the present invention also includes design changes within the scope of the present invention. Furthermore, the above-described embodiments can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in their purposes, configurations, etc. [Explanation of symbols]

[0037] 1: voltage fluctuation suppressor, 10: AC generator, 11: armature, 11A: output terminal, L R ,L S ,L T ,L U ,L W ,L O :wiring, C R ,C S ,C T ,C W ,C U : Current detection section, P R ,P S ,P T ,P U ,P W ,P O :detection point, 20: control device, 21: load current detection unit, 22: used output terminal identification unit, 23: Terminal voltage detection unit, 24: Excitation control unit, 25: Output voltage calculation unit

Claims

1. A voltage fluctuation suppression device that is equipped in an AC generator and suppresses voltage fluctuations by excitation control based on output voltage, a load current detection unit that detects a load current at each output terminal; a used output terminal specifying unit that specifies a used output terminal based on the detection by the load current detecting unit; an inter-terminal voltage detection unit that detects an inter-terminal voltage including the output terminal identified by the used output terminal identification unit; A voltage fluctuation suppressing device for an AC generator, comprising an excitation control unit that performs excitation control using an output voltage determined from the terminal voltage detected by the terminal voltage detection unit.

2. an output voltage calculation unit that calculates an output voltage by performing arithmetic processing on the inter-terminal voltage detected by the inter-terminal voltage detection unit; 2. The voltage fluctuation suppressing device for an AC generator according to claim 1, wherein excitation control is performed based on the output voltage calculated by the output voltage calculation unit.

3. 3. The voltage fluctuation suppressing device for an AC generator according to claim 2, wherein the output voltage calculating unit sets the average value of the detected inter-terminal voltages as the output voltage when the output terminal to be used identified by the used output terminal identifying unit is a three-phase output terminal or a single-phase output terminal used alone.

4. 3. The voltage fluctuation suppressing device for an AC generator according to claim 2, wherein, when the output terminals to be used identified by the output terminal identification unit are three-phase output terminals and single-phase output terminals that are simultaneously used, the output voltage calculation unit sets an average value of the inter-terminal voltages of the three-phase output terminals as a first average value, sets an average value of the inter-terminal voltages of the single-phase output terminals and the first average value as a second average value, and sets the second average value as the output voltage.

5. 2. The voltage fluctuation suppressing device for an AC generator according to claim 1, wherein the AC generator has an armature winding having a single-phase output terminal connected to a three-phase connection of an armature winding having a three-phase output terminal.

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