Power generation system control device, power generation system, hydroelectric power generation system

Abstract

To suppress pulsations in the composite electric power obtained based on the electric power of a plurality of power generators.SOLUTION: A first converter (12) converts the electric power generated by a first power generator (11) into first electric power (P1) and supplies the first electric power to a DC unit (15). A second converter (14) converts the electric power generated by a second power generator (13) into second electric power (P2) and supplies the second electric power to the DC unit (15). A control unit (100) controls the first power generator (11) so that some or all of a plurality of pulsations included in the first electric power (P1) at peak time points do not match a plurality of pulsations included in the second electric power (P2) at peak time points.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a power generation system, a power generation system, and a hydroelectric power generation system. [Background technology]

[0002] Patent document 1 discloses a hydroelectric power generation system that includes multiple water turbines, multiple power generation devices that are individually provided corresponding to the multiple water turbines and generate electricity using the rotation of the water turbines as energy, and a control device that collectively controls the multiple power generation devices to output the generated electricity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-101760 Summary of the Invention [Problem to be solved by the invention]

[0004] In the power generation system of Patent Document 1, when generating a single composite power by combining multiple power outputs from multiple generators, if the peak times of multiple pulsations contained in each of the multiple generated powers coincide, the amplitude of the pulsations contained in the composite power becomes large. As such, it is difficult to suppress the pulsations contained in the composite power obtained based on the power of the multiple generators. [Means for solving the problem]

[0005] A first aspect of the present disclosure relates to a control device for a power generation system including a first generator (11), a first converter (12) that converts power generated by the first generator (11) into a first power (P1) and supplies it to a DC unit (15), a second generator (13), and a second converter (14) that converts power generated by the second generator (13) into a second power (P2) and supplies it to the DC unit (15), and the control device for this power generation system includes a control unit (100) that controls the first generator (11) so that some or all of the peak points of multiple pulsations contained in the first power (P1) do not coincide with the peak points of multiple pulsations contained in the second power (P2).

[0006] In the first mode, pulsations in the third power (P3), which is generated in the DC section (15) and obtained by combining the first power (P1) and the second power (P2), can be suppressed more effectively than in a case where the peak times of the multiple pulsations contained in the first power (P1) and the peak times of the multiple pulsations contained in the second power (P2) completely coincide with each other.

[0007] A second aspect of the present disclosure is a power generation system control device according to the first aspect, wherein the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed, and the product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from the product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the rotation speed of the second generator (13).

[0008] In the second aspect, the product of the "least common multiple of the number of poles and the number of slots of the first generator (11)" and the "first rotation speed (the rotation speed of the first generator (11))" can be made different from the product of the "least common multiple of the number of poles and the number of slots of the second generator (13)" and the "rotation speed of the second generator (13)." This makes it possible to prevent some or all of the peak times of the multiple pulsations included in the first power (P1) from coinciding with the peak times of the multiple pulsations included in the second power (P2), thereby suppressing the pulsations in the third power (P3).

[0009] A third aspect of the present disclosure is a control device for a power generation system of the second aspect, wherein the power generation system includes a first fluid machine (21) provided in a first flow path (2a) through which a fluid flows and driving the first generator (11), and a first adjustment mechanism (22) provided in series with the first fluid machine (21) in the first flow path (2a) and capable of adjusting the flow rate of the fluid flowing through the first flow path (2a), and the control unit (100) is a control device for a power generation system that controls the first adjustment mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes a first flow rate.

[0010] In the third aspect, the rotation speed of the first generator (11) can be set to the first rotation speed, and the flow rate of the fluid flowing through the first flow path (2a) can be set to the first flow rate.

[0011] A fourth aspect of the present disclosure is a power generation system control device according to the third aspect, wherein the control unit (100) controls the first adjustment mechanism (22) to decrease the flow rate of the fluid flowing through the first flow path (2a) when the rotation speed of the first generator (11) changes in a direction that increases the flow rate of the fluid flowing through the first flow path (2a), and controls the first adjustment mechanism (22) to increase the flow rate of the fluid flowing through the first flow path (2a) when the rotation speed of the first generator (11) changes in a direction that decreases the flow rate of the fluid flowing through the first flow path (2a).

[0012] In the fourth aspect, the rotation speed of the first generator (11) can be set to the first rotation speed, and the flow rate of the fluid flowing through the first flow path (2a) can be set to the first flow rate.

[0013] A fifth aspect of the present disclosure is a power generation system control device according to the first aspect, wherein the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed, controls the second generator (13) so that the rotation speed of the second generator (13) becomes a second rotation speed, and the product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from the product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the second rotation speed.

[0014] In the fifth aspect, the product of the "least common multiple of the number of poles and the number of slots of the first generator (11)" and the "first rotation speed (rotation speed of the first generator (11))" can be made different from the product of the "least common multiple of the number of poles and the number of slots of the second generator (13)" and the "second rotation speed (rotation speed of the second generator (13))." This makes it possible to prevent some or all of the peak times of the multiple pulsations included in the first power (P1) from coinciding with the peak times of the multiple pulsations included in the second power (P2), thereby suppressing the pulsations in the third power (P3).

[0015] A sixth aspect of the present disclosure provides the control device for a power generation system according to the fifth aspect, wherein the power generation system includes a first fluid machine (21) provided in a first flow path (2a) through which a fluid flows and driving the first generator (11), a first adjustment mechanism (22) provided in series with the first fluid machine (21) in the first flow path (2a) and capable of adjusting a flow rate of the fluid flowing through the first flow path (2a), a second fluid machine (23) provided in a second flow path (2b) through which a fluid flows and driving the second generator (13), and The power generation system control device includes a second adjustment mechanism (24) that is provided in series with the second fluid machine (23) in the second flow path (2b) and is capable of adjusting the flow rate of the fluid flowing through the second flow path (2b), the second flow path (2b) merges with the first flow path (2a), and the control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) becomes a target flow rate.

[0016] In the sixth aspect, the rotation speed of the first generator (11) can be set to the first rotation speed, the rotation speed of the second generator (13) can be set to the second rotation speed, and the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) can be set to the target flow rate.

[0017] A seventh aspect of the present disclosure is the control device for a power generation system of the sixth aspect, wherein the control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) decreases when the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) increases, and controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) increases when the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) decreases.

[0018] In the seventh aspect, the rotation speed of the first generator (11) can be set to the first rotation speed, the rotation speed of the second generator (13) can be set to the second rotation speed, and the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) can be set to the target flow rate.

[0019] An eighth aspect of the present disclosure is a power generation system control device according to the sixth aspect, wherein the control unit (100) controls the first adjustment mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes a first flow rate, and controls the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the second flow path (2b) becomes a second flow rate, the sum of the first flow rate and the second flow rate is the target flow rate, and the ratio of the first flow rate to the second flow rate is the same as the ratio of the first rotation speed to the second rotation speed.

[0020] In the eighth aspect, the rotation speed of the first generator (11) can be set to the first rotation speed, the rotation speed of the second generator (13) can be set to the second rotation speed, and the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) can be set to the target flow rate.

[0021] A ninth aspect of the present disclosure is a power generation system control device according to the first aspect, wherein the control unit (100) controls the first generator (11) so that the rotation angle of the first generator (11) is shifted relative to the rotation angle of the second generator (13), so that some or all of the peak points of the multiple pulsations contained in the first power (P1) do not coincide with the peak points of the multiple pulsations contained in the second power (P2).

[0022] In the ninth aspect, by shifting the rotation angle of the first generator (11) with respect to the rotation angle of the second generator (13) so that some or all of the peak times of the multiple pulsations contained in the first power (P1) do not coincide with the peak times of the multiple pulsations contained in the second power (P2), it is possible to suppress the pulsations in the third power (P3) more than in the case where the peak times of the multiple pulsations contained in the first power (P1) and the peak times of the multiple pulsations contained in the second power (P2) completely coincide with each other.

[0023] A tenth aspect of the present disclosure is a power generation system control device according to any one of the first to ninth aspects, wherein the power generation system includes a power consumer (17), and the control unit (100) controls the power consumer (17) so that a power pulsation exceeding a threshold value (Pth) in a third power (P3), which is power in the DC unit (15) and is obtained by combining the first power (P1) and the second power (P2), is consumed by the power consumer (17).

[0024] In the tenth aspect, the power pulsation of the third power (P3) that exceeds the threshold value (Pth) is consumed by the power consumer (17), thereby making it possible to suppress the pulsation of the third power (P3).

[0025] An eleventh aspect of the present disclosure is a power generation system control device according to any one of the first to tenth aspects, wherein the control unit (100) derives a first correction torque for reducing torque ripple of the first generator (11) based on the rotation angle of the first generator (11), and controls the torque of the first generator (11) based on the first correction torque.

[0026] In the eleventh aspect, the torque of the first generator (11) is controlled based on the first correction torque, thereby reducing the torque ripple of the first generator (11), thereby suppressing the pulsation in the third power (P3).

[0027] A twelfth aspect of the present disclosure is a power generation system control device according to the eleventh aspect, wherein the control unit (100) derives a second correction torque for reducing torque ripple of the second generator (13) based on the rotation angle of the second generator (13), and controls the torque of the second generator (13) based on the second correction torque.

[0028] In the twelfth aspect, the torque of the second generator (13) is controlled based on the second correction torque, thereby reducing the torque ripple of the second generator (13), thereby suppressing the pulsation in the third power (P3).

[0029] A thirteenth aspect of the present disclosure relates to a power generation system, the power generation system including a first generator (11), a first converter (12) that converts the power generated by the first generator (11) into a first power (P1) and supplies it to a DC unit (15), a second generator (13), a second converter (14) that converts the power generated by the second generator (13) into a second power (P2) and supplies it to the DC unit (15), and a control device, the control device being a control device of any one of the power generation systems of the first to twelfth aspects.

[0030] A fourteenth aspect of the present disclosure relates to a hydroelectric power generation system, which includes the power generation system of the thirteenth aspect, a first fluid machine (21) provided in a first flow path (2a) through which a fluid flows and driving the first generator (11), a first adjustment mechanism (22) provided in series with the first fluid machine (21) in the first flow path (2a) and capable of adjusting the flow rate of the fluid flowing through the first flow path (2a), a second fluid machine (23) provided in a second flow path (2b) through which a fluid flows and driving the second generator (13), and a second adjustment mechanism (24) provided in series with the second fluid machine (23) in the second flow path (2b) and capable of adjusting the flow rate of the fluid flowing through the second flow path (2b). [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a hydroelectric power generation system according to the first embodiment. [Figure 2] FIG. 2 is a graph illustrating the waveform of the power generated by the converter. [Figure 3] FIG. 3 is a graph illustrating the relationship between the first power and the second power in the first embodiment. [Figure 4] FIG. 4 is a graph illustrating the relationship between the "ratio of the predetermined product of the generator" and the "peak coincidence rate." [Figure 5] FIG. 5 is a graph illustrating a characteristic map of a hydroelectric power generation system. [Figure 6] FIG. 6 is a graph showing a first control example in a hydroelectric power generation system according to a first modification of the first embodiment. [Figure 7] FIG. 7 is a graph showing a second control example in the hydroelectric power generation system according to the first modification of the first embodiment. [Figure 8] FIG. 8 is a graph showing a third control example in the hydroelectric power generation system according to the first modification of the first embodiment. [Figure 9] FIG. 9 is a graph showing a fourth control example in the hydroelectric power generation system according to the first modification of the first embodiment. [Figure 10] FIG. 10 is a graph showing a fifth control example in the hydroelectric power generation system according to the first modification of the first embodiment. [Figure 11] FIG. 11 is a graph showing an example of control in the hydroelectric power generation system according to the second modification of the first embodiment. [Figure 12] FIG. 12 is a graph illustrating the relationship between the first power and the second power in the hydroelectric power generation system of the second embodiment. [Figure 13] FIG. 13 is a diagram illustrating the configuration of a hydroelectric power generation system according to the third embodiment. [Figure 14] FIG. 14 is a graph for explaining control in the hydroelectric power generation system of the third embodiment. [Figure 15] FIG. 15 is a diagram illustrating the configuration of a hydroelectric power generation system according to a first modification of the third embodiment. [Figure 16] FIG. 16 is a diagram for explaining control in the hydroelectric power generation system of the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and their description will not be repeated.

[0033] (Embodiment 1) FIG. 1 illustrates the configuration of a hydroelectric power generation system (1) according to a first embodiment. The hydroelectric power generation system (1) generates electricity by utilizing the energy of a fluid flowing through a flow path (2). In this example, the fluid is water. The flow path (2) constitutes a pipeline between a water distribution tank (3) and a water distribution target (4). An example of the water distribution target (4) is a water reservoir.

[0034] In this example, the flow path (2) includes a first flow path (2a) and a second flow path (2b) provided in parallel to the first flow path (2a). The second flow path (2b) branches off from the first flow path (2a) and merges with the first flow path (2a).

[0035] The hydroelectric power generation system (1) includes a first fluid machine (21), a first adjustment mechanism (22), a second fluid machine (23), a second adjustment mechanism (24), a first generator (11), a first converter (12), a second generator (13), a second converter (14), a DC unit (15), and an inverter (16). The hydroelectric power generation system (1) is capable of supplying electric power obtained by generating electric power to an electric power system (5). For example, the electric power system (5) is a so-called commercial electric power system.

[0036] [Fluid machinery and adjustment mechanisms] The first fluid machine (21) is provided in the first flow path (2a) and drives the first generator (11). The first adjustment mechanism (22) is provided in the first flow path (2a) in series with the first fluid machine (21) and is capable of adjusting the flow rate of the fluid flowing through the first flow path (2a). The second fluid machine (23) is provided in the second flow path (2b) and drives the second generator (13). The second adjustment mechanism (24) is provided in the second flow path (2b) in series with the second fluid machine (23) and is capable of adjusting the flow rate of the fluid flowing through the second flow path (2b).

[0037] In this example, each of the first fluid machine (21) and the second fluid machine (23) is configured by a water turbine. Examples of the water turbine include a pump reverse turbine, a propeller turbine, a cross-flow turbine, a submerged turbine turbine, a tubular turbine, a Kaplan turbine, a Pelton turbine, a Turgo impulse turbine, and a Francis turbine. Each of the first adjusting mechanism (22) and the second adjusting mechanism (24) is configured by an electric valve whose opening is adjustable.

[0038] [No. 1 Generator] The first generator (11) generates electricity when driven by the first fluid machine (21). In this example, the first generator (11) is connected to a water turbine, which is the first fluid machine (21), by a rotary shaft, and when the water turbine, which is the first fluid machine (21), rotates, the first generator (11) is rotationally driven. This causes the first generator (11) to perform regenerative operation. Electric power is generated by the regenerative operation of the first generator (11).

[0039] Specifically, the first generator (11) has a rotor and a stator. The rotor has a rotor core connected to a rotating shaft and a plurality of magnets provided in the rotor core. The plurality of magnets form a plurality of magnetic poles. For example, the rotor is a permanent magnet embedded rotor. The stator has a stator core in which a plurality of slots are formed and a plurality of coils housed in the plurality of slots.

[0040] [First converter] The first converter (12) converts the electric power generated by the first generator (11) into a first electric power (P1) and supplies the first electric power to the DC part (15). Specifically, the first converter (12) has a plurality of switching elements, and converts the electric power (AC power) generated by the first generator (11) into the first electric power (P1) by a switching operation.

[0041] [Second generator] The second generator (13) generates electricity when driven by the second fluid machine (23). In this example, the second generator (13) is connected to a water turbine, which is the second fluid machine (23), by a rotating shaft, and when the water turbine, which is the second fluid machine (23), rotates, the second generator (13) is rotationally driven. This causes the second generator (13) to perform regenerative operation. Electric power is generated by the regenerative operation of the second generator (13). The configuration of the second generator (13) is similar to the configuration of the first generator (11).

[0042] [Second converter] The second converter (14) converts the electric power generated by the second generator (13) into second electric power (P2) and supplies the second electric power (P2) to the DC part (15). The configuration of the second converter (14) is similar to the configuration of the first converter (12).

[0043] [DC section] The DC unit (15) is supplied with the first power (P1) obtained by the first converter (12) and the second power (P2) obtained by the second converter (14), thereby generating a third power (P3). The third power (P3) is power in the DC unit (15) and is obtained by combining the first power (P1) and the second power (P2). Each of the first power (P1), the second power (P2), and the third power (P3) is so-called "DC power," but includes a pulsating component. The pulsation of power will be described in detail later.

[0044] [Inverter] The inverter (16) converts the third power (P3) generated in the DC section (15) into AC power and supplies the AC power to the power grid (5). Specifically, the inverter (16) has a plurality of switching elements and converts the third power (P3) into AC power by switching operations.

[0045] [Various sensors] The hydroelectric power generation system 1 is provided with various sensors (not shown). The various sensors are provided to detect various physical quantities in the hydroelectric power generation system 1. Various pieces of information obtained by these various sensors are transmitted to the control device 10.

[0046] In this example, there are provided a first flow rate sensor for detecting the flow rate of the fluid flowing through the first flow path (2a), a second flow rate sensor for detecting the flow rate of the fluid flowing through the second flow path (2b), a first rotation speed sensor for detecting the rotation speed of the first generator (11), a first rotation angle sensor for detecting the rotation angle of the first generator (11), a second rotation speed sensor for detecting the rotation speed of the second generator (13), a second rotation angle sensor for detecting the rotation angle of the second generator (13), a first power sensor for detecting the first power (P1), a second power sensor for detecting the second power (P2), a third power sensor for detecting the third power (P3), etc. For example, the first power (P1), the second power (P2), and the third power (P3) are detected as "voltage" and "current."

[0047] The various sensors described above may be sensors provided to directly detect the physical quantities described above, or may be sensors provided to indirectly detect or estimate the physical quantities described above.

[0048] [Control device] The control device (10) controls the hydroelectric power generation system (1). The control device (10) is an example of a control device for a power generation system. In this example, the control device (10) includes a storage unit (101) and a control unit (100).

[0049] [Storage section] The storage unit 101 stores various types of information and data, such as information used to control the hydroelectric power generation system 1 (e.g., set values ​​such as thresholds), information obtained by various sensors provided in the hydroelectric power generation system 1 (e.g., measured values), and the like.

[0050] [Control Unit] The control unit (100) performs various processes. Specifically, the control unit (100) acquires information and data from each part of the hydroelectric power generation system (1) and performs various processes based on the information and data.

[0051] For example, the control unit (100) is configured by a computer (microcomputer) including a processor, memory, an input / output interface, etc. The memory is electrically connected to the processor and stores programs and data for operating the processor. The processor executes the programs to realize various functions of the control unit (100). The control unit (100) also includes components for control (e.g., electric circuits, electronic circuits, etc.).

[0052] [Processing by the control unit] The control unit (100) controls the first generator (11) so that some or all of the peak times of the pulsations included in the first power (P1) do not coincide with the peak times of the pulsations included in the second power (P2). The pulsations included in each of the first power (P1) and the second power (P2) will be described in detail later.

[0053] In the first embodiment, the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed. Note that the product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from the product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the rotation speed of the second generator (13). Note that the "number of poles" here refers to the number of poles of the rotor, and the "number of slots" refers to the number of slots of the stator.

[0054] In this example, the control unit (100) controls not only the first generator (11) but also both the first generator (11) and the second generator (13). The control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed, and controls the second generator (13) so that the rotation speed of the second generator (13) becomes a second rotation speed. The product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from the product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the second rotation speed.

[0055] Specifically, in this example, the first generator (11) and the second generator (13) have the same specifications, and the least common multiple of the number of poles and the number of slots of the first generator (11) is the same as the least common multiple of the number of poles and the number of slots of the second generator (13). The first rotation speed is set to a rotation speed different from the second rotation speed.

[0056] In this example, the control unit (100) controls the first generator (11) by controlling the first converter (12). Specifically, the control unit (100) controls the rotation speed of the first generator (11) by controlling the switching operation of the first converter (12). Similarly, the control unit (100) controls the second generator (13) by controlling the second converter (14).

[0057] [Pulsation of the first and second power sources] Next, the pulsation (AC component included in DC power) included in each of the first power (P1) and the second power (P2) will be described with reference to Fig. 2. Since the pulsation of the first power (P1) and the pulsation of the second power (P2) are similar to each other, the following description will focus on the "pulsation of the first power (P1)."

[0058] The electric power generated by the regenerative operation of the first generator (11) pulsates periodically at the "least common multiple of the number of poles and the number of slots of the first generator (11)" due to spatial harmonic components resulting from the structure of the first generator (11). Therefore, in one cycle (one cycle corresponding to one rotation of the first generator (11)) of the first electric power (P1) obtained based on the electric power generated by the first generator (11), pulsations appear periodically in the same number as the least common multiple of the number of poles and the number of slots of the first generator (11).

[0059] As shown in FIG. 2, the first power (P1) contains multiple pulsations. When the rotation speed of the first generator (11) is constant, the rotation angles of the peak times (Tp) of these multiple pulsations are theoretically equally spaced. The peak time (Tp) of one pulsation is the time when the amplitude of that pulsation reaches its maximum value (peak value). For example, when the first generator (11) has four poles and 24 slots, one cycle of the first power (P1) contains 24 pulsations.

[0060] Furthermore, the period of the multiple pulsations included in the first power (P1) is inversely proportional to the rotation speed of the first generator (11). As the rotation speed of the first generator (11) increases, one period of the first power (P1) (one period corresponding to one rotation of the first generator (11)) becomes shorter, and as a result, the period of the multiple pulsations included in the first power (P1) becomes shorter.

[0061] [Relationship between First Power and Second Power] Next, the relationship between the first power (P1) and the second power (P2) in the first embodiment will be described with reference to Fig. 3. Hereinafter, the product of the "least common multiple of the number of poles and the number of slots of the generators" and the "rotational speed of the generators" will be referred to as the "predetermined product," the predetermined product related to the first generator (11) will be referred to as the "first product," and the predetermined product related to the second generator (13) will be referred to as the "second product."

[0062] 3, the second product is 1.5 times the first product. Specifically, in this example, the least common multiple of the number of poles and the number of slots of the second generator (13) is the same as the least common multiple of the number of poles and the number of slots of the first generator (11), and the second rotation speed, which is the target rotation speed of the second generator (13), is set to 1.5 times the first rotation speed, which is the target rotation speed of the first generator (11).

[0063] In the example of Fig. 3, the peak times of the "first," "third," and "fifth" of the six pulsations included in the first power (P1) coincide with the peak times of the "first," "fourth," and "seventh" pulsations of the second power (P2), but the peak times of the "second," "fourth," and "fifth" pulsations of the first power (P1) do not coincide with the peak times of the pulsations of the second power (P2). In this way, by making the first product and the second product different, some or all (some in the example of Fig. 3) of the peak times of the multiple pulsations included in the first power (P1) do not coincide with the peak times of the multiple pulsations included in the second power (P2).

[0064] [Peak coincidence rate] Next, the relationship between the "ratio of the specified products of the generators" and the "peak coincidence division rate" will be described with reference to Figure 4. The horizontal axis of Figure 4 indicates the ratio of the specified products of the generators, and the vertical axis of Figure 5 indicates the peak coincidence division rate. The "ratio of the specified products of the generators" above refers to the ratio of the "larger product" of the first product and the second product to the "smaller product." The "peak coincidence division rate" above refers to the rate of peak times that coincide with the "peak time of the pulsation included in the power with the larger specified product from the first power (P1) and the second power (P2)" among the multiple peak times of pulsation included in the power with the smaller specified product from the first power (P1) and the second power (P2).

[0065] For example, if the peak coincidence division ratio is to be set to less than 0.5, the rotation speed of the first generator (11), that is, the “first rotation speed,” may be shifted from the rotation speed of the second generator (13), that is, the “second rotation speed,” so that the ratio of the predetermined products of the generators does not become 0.5×N (N is a natural number equal to or greater than 2).

[0066] [Effects of the First Embodiment] As described above, in the hydroelectric power generation system (1) of embodiment 1, the control unit (100) controls the first generator (11) so that some or all of the peak times of the multiple pulsations contained in the first power (P1) do not coincide with the peak times of the multiple pulsations contained in the second power (P2).

[0067] In the above configuration, pulsations in the third power (P3), which is generated in the DC section (15) and obtained by combining the first power (P1) and the second power (P2), can be suppressed more effectively than in a case where the peak times of the multiple pulsations included in the first power (P1) and the peak times of the multiple pulsations included in the second power (P2) completely coincide with each other.

[0068] In the hydroelectric power generation system (1) of the first embodiment, the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed. Note that the product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from the product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the rotation speed of the second generator (13).

[0069] In the above configuration, the product of the "least common multiple of the number of poles and the number of slots of the first generator (11)" and the "first rotation speed (the rotation speed of the first generator (11))" can be made different from the product of the "least common multiple of the number of poles and the number of slots of the second generator (13)" and the "rotation speed of the second generator (13)." This makes it possible to prevent some or all of the peak times of the multiple pulsations included in the first power (P1) from coinciding with the peak times of the multiple pulsations included in the second power (P2), thereby suppressing the pulsations in the third power (P3).

[0070] In the hydroelectric power generation system (1) of the first embodiment, the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed, and controls the second generator (13) so that the rotation speed of the second generator (13) becomes a second rotation speed. Note that the product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from the product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the second rotation speed.

[0071] In the above configuration, the product of the "least common multiple of the number of poles and the number of slots of the first generator (11)" and the "first rotation speed (rotation speed of the first generator (11))" can be made different from the product of the "least common multiple of the number of poles and the number of slots of the second generator (13)" and the "second rotation speed (rotation speed of the second generator (13))." This makes it possible to prevent some or all of the peak times of the multiple pulsations included in the first power (P1) from coinciding with the peak times of the multiple pulsations included in the second power (P2), thereby suppressing the pulsations in the third power (P3).

[0072] (Modification 1 of Embodiment 1) The hydroelectric power generation system (1) of Modification 1 of Embodiment 1 differs from the hydroelectric power generation system (1) of Embodiment 1 in the processing by the control unit (100). The other configurations and processing of the hydroelectric power generation system (1) of Modification 1 of Embodiment 1 are similar to those of the hydroelectric power generation system (1) of Embodiment 1.

[0073] In the hydroelectric power generation system (1) according to the first modification of the first embodiment, the control unit (100) controls the flow rate of the fluid flowing through the flow path (2) based on the characteristic map (M).

[0074] [Characteristics map (operating parameters of hydroelectric power generation system)] Next, the characteristic map (M) of the hydroelectric power generation system (1) will be described with reference to Fig. 5. The characteristic map (M) shows the relationships between various operating parameters of the hydroelectric power generation system (1).

[0075] The vertical axis of Fig. 5 indicates the effective head (H) of the water turbine that constitutes the fluid machine, and the horizontal axis of Fig. 5 indicates the flow rate (Q) through the water turbine. Here, the effective head (H) of the water turbine is the total head (Ho) from the liquid level in the distribution tank (3) to the outlet end of the flow path (2) minus the head corresponding to the pipeline resistance from the fluid in the distribution tank (3) through the flow path (2) to the outlet end of the flow path (2).

[0076] The relationship between the effective head (H) and the flow rate (Q) can be expressed by the system loss curve (S) (flow resistance characteristic curve) shown in Figure 3. The system loss curve (S) has the characteristic that the effective head (H) when the flow rate (Q) = 0 is the total head (Ho), and that the effective head (H) decreases quadratically as the flow rate (Q) increases. The curvature of the system loss curve (S) has a value specific to flow path (2) in Figure 1. The flow rate (Q) in flow path (2) and the effective head (H) at that time correspond to points on the system loss curve (S). In other words, the point corresponding to the turbine's flow rate (Q) and effective head (H) (the turbine's operating point) is always on the system loss curve (S).

[0077] The characteristic map (M) in Figure 5 shows the generator torque (T), generator rotation speed (N), and generator power output (P) as characteristics correlated with the turbine flow rate (Q) and effective head (H).

[0078] In the characteristic map (M), the region in which the turbine can operate (operable region) is formed between the "unconstrained curve (T=0)", which is the curve where the generator torque (T) is zero, and the "operating limit curve", which is the curve where the generator rotation speed (N) is zero or a specified minimum rotation speed. In Figure 5, the region to the left of the unconstrained curve is the turbine braking region (powering region).

[0079] In the operable range, multiple constant torque curves follow the unconstrained curve, and on the characteristic map (M), torque (T) increases as the flow rate (Q) increases. Additionally, multiple constant speed curves follow the operating limit curve, and the rotation speed (N) increases as the effective head (H) increases. On the system loss curve (S), torque (T) decreases as the flow rate (Q) decreases. Additionally, on the system loss curve (S), rotation speed (N) decreases as the flow rate (Q) increases. The constant power generation curve shown by the dashed line is a downward convex curve, and the generated power (P) also increases as the effective head (H) and flow rate (Q) increase.

[0080] The relationships among the parameters of the characteristic map (M) as described above are stored in the storage unit (101) (or the memory of the control unit (100)) in the form of a table (mathematical table) or a mathematical formula (function) in a program. Therefore, the control unit (100) can perform various calculations and controls by utilizing the relationships among the parameters represented in the characteristic map (M).

[0081] [Processing by the control unit] In the hydroelectric power generation system (1) of the first modification of the first embodiment, the control unit (100) controls the first adjustment mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes the first flow rate.

[0082] Specifically, when the rotation speed of the first generator (11) changes in a direction that increases the flow rate of the fluid flowing through the first flow path (2a), the control unit (100) controls the first adjustment mechanism (22) to decrease the flow rate of the fluid flowing through the first flow path (2a). Furthermore, when the rotation speed of the first generator (11) changes in a direction that decreases the flow rate of the fluid flowing through the first flow path (2a), the control unit (100) controls the first adjustment mechanism (22) to increase the flow rate of the fluid flowing through the first flow path (2a).

[0083] In this example, the control unit (100) controls not only the first adjustment mechanism (22) but also both the first adjustment mechanism (22) and the second adjustment mechanism (24). The control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) becomes the target flow rate. Note that the phrase "controlling the first adjustment mechanism (22) or the second adjustment mechanism (24)" means "controlling at least one of the first adjustment mechanism (22) and the second adjustment mechanism (24)." The same applies to the following similar descriptions.

[0084] Specifically, the control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) decreases when the sum of the flow rates of the fluid flowing through the first flow path (2a) and the second flow path (2b) increases. Furthermore, the control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) increases when the sum of the flow rates of the fluid flowing through the first flow path (2a) and the second flow path (2b) decreases.

[0085] [Control example] Next, with reference to Figures 6 to 10, the control (rotation speed control and flow rate control) in the power generation system (1) of Modification 1 of Embodiment 1 will be specifically described. Hereinafter, the flow rate of the fluid flowing through the first flow path (2a) will be referred to as the "first flow path flow rate," and the first flow rate, which is the target amount of the first flow path flow rate, will be referred to as the "first target flow rate." Similarly, the flow rate of the fluid flowing through the second flow path (2b) will be referred to as the "second flow path flow rate," and the second flow rate, which is the target amount of the second flow path flow rate, will be referred to as the "second target flow rate."

[0086] Furthermore, the motor-operated valve constituting the first adjustment mechanism (22) will be referred to as the “first motor-operated valve (22),” and the motor-operated valve constituting the second adjustment mechanism (24) will be referred to as the “second motor-operated valve (24).” The system loss curve (S) related to the operating point of the first generator (11) will be referred to as the “first system loss curve (S1),” and the system loss curve (S) related to the operating point of the second generator (13) will be referred to as the “second system loss curve (S2).”

[0087] [Control example 1] First, with reference to FIG. 6, a description will be given of control in the case where the second rotation speed, which is the target rotation speed of the second generator (13), is changed from "the same rotation speed as the first rotation speed" to "a rotation speed higher than the first rotation speed."

[0088] When the second rotational speed increases as described above, the rotational speed of the second generator (13) increases. When the rotational speed of the second generator (13) increases, the operating point of the second generator (13) moves on the second system loss curve (S2) from "operating point (A2) where the second flow path flow rate is the second target flow rate (Q2)" to "operating point (B2) where the second flow path flow rate is less than the second target flow rate (Q2)."

[0089] Therefore, the control unit (100) increases the aperture of the second electric valve (24) to increase the second flow rate while maintaining the rotation speed of the second generator (13). As a result, the second system loss curve (S2) changes as shown by the arrow in Fig. 6, and the operating point of the second generator (13) shifts from "operating point (B2) where the second flow path flow rate is less than the second target flow rate (Q2)" to "operating point (C2) where the second flow path flow rate becomes the second target flow rate (Q2)."

[0090] Since the rotation speed of the first generator (11) and the opening of the first motor-operated valve (22) are maintained without change, the operating point of the first generator (11) is maintained at the operating point (A1) on the first system loss curve (S1).

[0091] [Control example 2] Next, referring to Figure 7, we will explain the control when the second target flow rate (Q2) is changed from "a flow rate identical to the first target flow rate (Q1)" to "a flow rate smaller than the first target flow rate (Q1)" when the target flow rate decreases.

[0092] When the second target flow rate (Q2) decreases as described above, the control unit (100) reduces the aperture of the second motor-operated valve (24) so ​​that the second flow path flow rate decreases to the changed second target flow rate (Q2) while maintaining the rotation speed of the second generator (13) at the second rotation speed. This changes the second system loss curve (S2) as shown by the arrow in Fig. 7, and the operating point of the second generator (13) shifts from "operating point (A2) where the second flow path flow rate is greater than the changed second target flow rate (Q2)" to "operating point (B2) where the second flow path flow rate becomes the changed second target flow rate (Q2)."

[0093] Since the rotation speed of the first generator (11) and the opening of the first motor-operated valve (22) are maintained without change, the operating point of the first generator (11) is maintained at the operating point (A1) on the first system loss curve (S1).

[0094] [Control Example 3] Next, with reference to FIG. 8, a description will be given of control in which the first target flow rate (Q1) is increased by a predetermined amount and the second target flow rate (Q2) is decreased by a predetermined amount in order to make the rotation speed of the first generator (11) and the rotation speed of the second generator (13) different from each other.

[0095] As described above, when the first target flow rate (Q1) increases, the control unit (100) reduces the rotation speed of the first generator (11) so that the first flow path flow rate increases to the changed first target flow rate (Q1). As a result, the operating point of the first generator (11) moves on the first system loss curve (S1) from "operating point (A1) where the first flow path flow rate is smaller than the changed first target flow rate (Q1)" to "operating point (A2) where the first flow path flow rate becomes the changed first target flow rate (Q1)."

[0096] Furthermore, as described above, when the second target flow rate (Q2) decreases, the control unit (100) increases the rotation speed of the second generator (13) so that the second flow path flow rate decreases to the changed second target flow rate (Q2). As a result, the operating point of the second generator (13) moves on the second system loss curve (S2) from "operating point (B1) where the second flow path flow rate is greater than the changed second target flow rate (Q2)" to "operating point (B2) where the second flow path flow rate becomes the changed second target flow rate (Q2)."

[0097] [Control Example 4 and Control Example 5] 9 and 10, a description will be given of control when the effective head (H) increases due to a pressure disturbance while the first generator (11) and the second generator (13) are in speed control operation. In this case, the first flow path flow rate becomes larger than the first target flow rate (Q1) by a predetermined amount corresponding to the increase in the effective head (H), and the second flow path flow rate also becomes larger than the second target flow rate (Q2) by a predetermined amount corresponding to the increase in the effective head (H).

[0098] In the example of FIG. 9 (control example 4), the control unit (100) reduces the opening of the first electric valve (22) and the opening of the second electric valve (24) by the same amount so that the first flow path flow rate and the second flow path flow rate decrease by the same amount (specifically, a predetermined amount according to an increase in the effective head (H)) to become the first target flow rate (Q1) and the second target flow rate (Q2), while maintaining the rotation speed of the first generator (11) and the rotation speed of the second generator (13).

[0099] As a result, the first system loss curve (S1) and the second system loss curve (S2) change in the same manner, as shown by the arrows in Fig. 9. The operating point of the first generator (11) moves from "operating point (A1) where the first flow path flow rate is greater than the first target flow rate (Q1)" to "operating point (A2) where the first flow path flow rate becomes the first target flow rate (Q1)." The operating point of the second generator (13) moves from "operating point (B1) where the second flow path flow rate is greater than the second target flow rate (Q2)" to "operating point (B2) where the second flow path flow rate becomes the second target flow rate (Q2)."

[0100] 10 (control example 5), the control unit (100) performs a first control of decreasing the aperture of the first motor-operated valve (22) so that the first flow path flow rate decreases by a predetermined amount to reach a first target flow rate (Q1) while maintaining the rotation speed of the first generator (11), and a second control of decreasing the aperture of the second motor-operated valve (24) so ​​that the second flow path flow rate decreases by a predetermined amount to reach a second target flow rate (Q2) while maintaining the rotation speed of the second generator (13). In this example, the changed aperture of the second motor-operated valve (24) is different from the changed aperture of the first motor-operated valve (22).

[0101] As a result, the first system loss curve (S1) and the second system loss curve (S2) change as shown by the arrows in Fig. 10. In this example, the second system loss curve (S2) after the change is different from the first system loss curve (S1) after the change. The operating point of the first generator (11) moves from "operating point (A1) where the first flow path flow rate is greater than the first target flow rate (Q1)" to "operating point (A2) where the first flow path flow rate becomes the first target flow rate (Q1)". The operating point of the second generator (13) moves from "operating point (B1) where the second flow path flow rate is greater than the second target flow rate (Q2)" to "operating point (B2) where the second flow path flow rate becomes the second target flow rate (Q2)".

[0102] [Effects of Modification 1 of Embodiment 1] As described above, in the hydroelectric power generation system (1) of the first modification of the first embodiment, the control unit (100) controls the first adjustment mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes the first flow rate.

[0103] Specifically, when the rotation speed of the first generator (11) changes in a direction that increases the flow rate of the fluid flowing through the first flow path (2a), the control unit (100) controls the first adjustment mechanism (22) to decrease the flow rate of the fluid flowing through the first flow path (2a). Furthermore, when the rotation speed of the first generator (11) changes in a direction that decreases the flow rate of the fluid flowing through the first flow path (2a), the control unit (100) controls the first adjustment mechanism (22) to increase the flow rate of the fluid flowing through the first flow path (2a).

[0104] In the above configuration, the rotation speed of the first generator (11) can be set to the first rotation speed, and the flow rate of the fluid flowing through the first flow path (2a) can be set to the first flow rate.

[0105] Furthermore, in the hydroelectric power generation system (1) of the first variant of the first embodiment, the control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) becomes the target flow rate.

[0106] Specifically, the control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) decreases when the sum of the flow rates of the fluid flowing through the first flow path (2a) and the second flow path (2b) increases. Furthermore, the control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) increases when the sum of the flow rates of the fluid flowing through the first flow path (2a) and the second flow path (2b) decreases.

[0107] In the above configuration, the rotation speed of the first generator (11) can be set to the first rotation speed, the rotation speed of the second generator (13) can be set to the second rotation speed, and the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) can be set to the target flow rate.

[0108] (Modification 2 of Embodiment 1) The hydroelectric power generation system (1) of the second modification of the first embodiment differs from the hydroelectric power generation system (1) of the first embodiment in the processing by the control unit (100). The other configurations and processing of the hydroelectric power generation system (1) of the second modification of the first embodiment are the same as those of the hydroelectric power generation system (1) of the first embodiment.

[0109] In the hydroelectric power generation system (1) of the second modification of the first embodiment, similarly to the hydroelectric power generation system (1) of the first modification of the first embodiment, the control unit (100) controls the flow rate of the fluid flowing through the flow path (2) based on the characteristic map (M).

[0110] In the hydroelectric power generation system (1) of the second modification of the first embodiment, the control unit (100) controls the first adjustment mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes a first flow rate, and controls the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the second flow path (2b) becomes a second flow rate. The sum of the first flow rate and the second flow rate is the target flow rate. The ratio between the first flow rate and the second flow rate is the same as the ratio between the first rotation speed and the second rotation speed.

[0111] Hereinafter, the flow rate of the fluid flowing through the first flow path (2a) will be referred to as the "first flow path flow rate," and the flow rate of the fluid flowing through the second flow path (2b) will be referred to as the "second flow path flow rate." The "first flow rate," which is the target amount of the first flow path flow rate, will be referred to as the "first target flow rate (Q1)," the "second flow rate," which is the target amount of the second flow path flow rate, will be referred to as the "second target flow rate (Q2)," and the "target flow rate," which is the sum of the first target flow rate (Q1) and the second target flow rate (Q2), will be referred to as the "total target flow rate (Q0)."

[0112] For example, as shown in Fig. 11, when the operating point of the first generator (11) and the operating point of the second generator (13) move on the "maximum turbine efficiency curve (a curve indicating the characteristics at which the turbine can be operated at maximum efficiency)," the relationship between the flow rate (Q) and the rotational speed (N) remains constant. Specifically, the ratio between the first target flow rate (Q1) and the first rotational speed (N1) (the target rotational speed of the first generator (11)) is equal to the ratio between the second target flow rate (Q2) and the second rotational speed (N2) (the rotational speed of the second generator (13)), and the relationship "Q1 / N1 = Q2 / N2" holds.

[0113] Here, if the first rotation speed (N1) and the second rotation speed (N2) are set so that the "ratio of the specified product of the generator" is "1.25" to make the "peak coincidence ratio" shown in FIG. 4 less than "0.5," the relationship between the first rotation speed (N1) and the second rotation speed (N2) is "N1 = 5 / 4 × N2." From the above relationship, the relationship between the first target flow rate (Q1) and the second target flow rate (Q2) is "Q1 / Q2 = 5 / 4." Note that since the total target flow rate (Q0), which is the sum of the first target flow rate (Q1) and the second target flow rate (Q2), is constant, the first target flow rate (Q1) is "Q1 = 5 / 9 × Q0," and the second target flow rate (Q2) is "Q2 = 4 / 9 × Q0."

[0114] Then, by controlling the first flow path flow rate and the second flow path flow rate based on the above-mentioned first target flow rate (Q1) and second target flow rate (Q2), the relationship between the rotation speed of the first generator (11) and the rotation speed of the second generator (13) can be made to be a predetermined relationship.

[0115] [Effects of Modification 2 of Embodiment 1] As described above, in the hydroelectric power generation system (1) of the second modification of the first embodiment, the control unit (100) controls the first adjustment mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes the first flow rate, and controls the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the second flow path (2b) becomes the second flow rate. The sum of the first flow rate and the second flow rate is the target flow rate. The ratio of the first flow rate to the second flow rate is the same as the ratio of the first rotation speed to the second rotation speed.

[0116] In the above configuration, the rotation speed of the first generator (11) can be set to the first rotation speed, the rotation speed of the second generator (13) can be set to the second rotation speed, and the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) can be set to the target flow rate.

[0117] (Embodiment 2) The hydroelectric power generation system (1) of the second embodiment differs from the hydroelectric power generation system (1) of the first embodiment in the processing by the control unit (100). The other configurations and processing of the hydroelectric power generation system (1) of the second embodiment are the same as those of the hydroelectric power generation system (1) of the first embodiment.

[0118] In the hydroelectric power generation system (1) of embodiment 2, the control unit (100) controls the first generator (11) so that the rotation angle of the first generator (11) is shifted relative to the rotation angle of the second generator (13) so that some or all of the peak times of the multiple pulsations contained in the first power (P1) do not coincide with the peak times of the multiple pulsations contained in the second power (P2).

[0119] In this example, the product of the "least common multiple of the number of poles and the number of slots of the first generator (11)" and the "first rotation speed (rotation speed of the first generator (11))" is the same as the product of the "least common multiple of the number of poles and the number of slots of the second generator (13)" and the "second rotation speed (rotation speed of the second generator (13))." Specifically, the least common multiple of the number of poles and the number of slots of the first generator (11) is the same as the least common multiple of the number of poles and the number of slots of the second generator (13), and the first rotation speed (rotation speed of the first generator (11)) is the same as the second rotation speed (rotation speed of the second generator (13)).

[0120] [Amount of deviation in the generator rotation angle] Next, the deviation of the rotation angle of the first generator (11) from the rotation angle of the second generator (13) will be described with reference to Fig. 12. Hereinafter, the phase difference between the "peak point" at which the amplitude of one pulsation reaches its maximum value (h) and the "half point" at which the amplitude of one pulsation reaches half of the maximum value (h) will be referred to as the "reference phase difference (θ)."

[0121] 12, the deviation of the rotation angle of the first generator (11) from the rotation angle of the second generator (13) is twice the reference phase difference (θ). This makes it possible to make the maximum value of pulsation of the third power (P3), which is the combined power of the first power (P1) and the second power (P2), approximately the same as the maximum value of pulsation of the first power (P1) (or the second power (P2)).

[0122] [Processing by the control unit] Next, the processing by the control unit (100) of the second embodiment will be described. In this example, the least common multiple of the number of poles and the number of slots of the first generator (11) is the same as the least common multiple of the number of poles and the number of slots of the second generator (13). Furthermore, the angle obtained by dividing 360° by the least common multiple of the number of poles and the number of slots of the first generator (11) is referred to as the "upper limit angle," and the angle obtained by subtracting "twice the reference phase difference (θ)" from the "upper limit angle" is referred to as the "upper limit phase difference." The control unit (100) repeatedly performs the following processing.

[0123] First, the control unit (100) detects the rotation angle of the first generator (11) corresponding to the peak time of the pulsation of the first power (P1), detects the rotation angle of the second generator (13) corresponding to the peak time of the pulsation of the second power (P2), and then derives the difference between the rotation angle of the first generator (11) and the rotation angle of the second generator (13).

[0124] Next, the control unit (100) determines whether the derived “difference between the rotation angle of the first generator (11) and the rotation angle of the second generator (13)” is equal to or greater than “twice the reference phase difference (θ)” and is equal to or smaller than “the upper limit phase difference.” If the “difference between the rotation angle of the first generator (11) and the rotation angle of the second generator (13)” is within the above range, the process ends.

[0125] On the other hand, when the "difference between the rotation angle of the first generator (11) and the rotation angle of the second generator (13)" is not within the above range, the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) increases (or decreases) by a predetermined amount. Then, after a predetermined time has elapsed, the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) returns to the "rotation speed before the increase (or decrease)." This causes a deviation in the rotation angle of the first generator (11).

[0126] By repeating the above process, the “difference between the rotation angle of the first generator (11) and the rotation angle of the second generator (13)” is maintained within a range of “twice the reference phase difference (θ)” or more and “upper limit phase difference” or less.

[0127] [Effects of the Second Embodiment] The hydroelectric power generation system (1) of the second embodiment can achieve the same effects as those of the hydroelectric power generation system (1) of the first embodiment.

[0128] In addition, in the hydroelectric power generation system (1) of embodiment 2, the control unit (100) controls the first generator (11) so that the rotation angle of the first generator (11) is shifted relative to the rotation angle of the second generator (13), so that some or all of the peak times of the multiple pulsations contained in the first power (P1) do not coincide with the peak times of the multiple pulsations contained in the second power (P2).

[0129] In the above configuration, by shifting the rotation angle of the first generator (11) with respect to the rotation angle of the second generator (13) so that some or all of the peak times of the multiple pulsations contained in the first power (P1) do not coincide with the peak times of the multiple pulsations contained in the second power (P2), the pulsations in the third power (P3) can be suppressed more effectively than in the case where the peak times of the multiple pulsations contained in the first power (P1) and the peak times of the multiple pulsations contained in the second power (P2) completely coincide with each other.

[0130] (Modification 1 of Embodiment 2) In the hydroelectric power generation system (1) of the second embodiment, the control unit (100) may control both the first generator (11) and the second generator (13). Specifically, the control unit (100) may control the first generator (11) or the second generator (13) so that the rotation angle of the first generator (11) is shifted from the rotation angle of the second generator (13) so that some or all of the peak times of the multiple pulsations included in the first power (P1) do not coincide with the peak times of the multiple pulsations included in the second power (P2).

[0131] (Modification 2 of Embodiment 2) Furthermore, in the hydroelectric power generation system (1) of embodiment 2, if the "deviation amount of the rotation angle of the first generator (11) from the rotation angle of the second generator (13)" when some or all of the peak points of the multiple pulsations included in the first power (P1) do not coincide with the peak points of the multiple pulsations included in the second power (P2) is determined in advance as a "reference deviation amount (e.g., 1 / 2 of the upper limit angle)," the control unit (100) may control the first generator (11) or the second generator (13) so that the deviation amount of the rotation angle of the first generator (11) from the rotation angle of the second generator (13) becomes the reference deviation amount.

[0132] (Embodiment 3) FIG. 13 illustrates the configuration of a hydroelectric power generation system (1) of the third embodiment. The hydroelectric power generation system (1) of the third embodiment includes a power consumer (17) in addition to the configuration of the hydroelectric power generation system (1) of the first embodiment. Furthermore, the hydroelectric power generation system (1) of the third embodiment differs from the hydroelectric power generation system (1) of the first embodiment in the processing by the control unit (100). The other configurations and processing of the hydroelectric power generation system (1) of the third embodiment are similar to the configurations and processing of the hydroelectric power generation system (1) of the first embodiment.

[0133] In the hydroelectric power generation system (1) of the third embodiment, the control unit (100) performs power consumption processing in addition to the processing performed by the control unit (100) of the first embodiment. In the power consumption processing, the control unit (100) controls the power consumer (17) so that the power consumer (17) consumes power pulsation exceeding a threshold value (Pth) in the third power (P3), which is power in the DC unit (15) and is obtained by combining the first power (P1) and the second power (P2).

[0134] The power consumer 17 includes a load 17a and a switch 17b. For example, the load 17a is configured with a resistive element. The switch 17b is configured with a switching element such as an IGBT (Insulated Gate Bipolar Transistor). Turning the switch 17b on consumes a third power P3. Turning the switch 17b off stops the consumption of the third power P3.

[0135] 14, for example, the threshold (Pth) may be set to the lower limit of the third power (P3). Note that the threshold (Pth) may be set to a value higher than the lower limit of the third power (P3). However, the threshold (Pth) is lower than the upper limit of the third power (P3).

[0136] [Power consumption processing] Next, a description will be given of the power consumption process performed by the control unit (100) of the third embodiment. First, the control unit (100) detects the third power (P3) for at least one cycle, and sets the threshold value (Pth) based on the detected third power (P3). Then, the control unit (100) repeatedly performs the following process.

[0137] The control unit (100) detects the instantaneous value of the third power (P3) and determines whether the instantaneous value of the third power (P3) exceeds a threshold value (Pth).

[0138] When the instantaneous value of the third power (P3) exceeds the threshold value (Pth), the control unit (100) derives an "excess value" by subtracting the threshold value (Pth) from the instantaneous value of the third power (P3), and controls the on / off of the switch (17b) according to the excess value. Specifically, the control unit (100) controls the on / off of the switch (17b) according to the excess value so that the on time (time in the on state) of the switch (17b) increases as the excess value increases.

[0139] On the other hand, if the instantaneous value of the third power (P3) does not exceed the threshold value (Pth), the control unit (100) keeps the switch (17b) in the OFF state.

[0140] [Effects of the Third Embodiment] The hydroelectric power generation system (1) of the third embodiment can achieve the same effects as those of the hydroelectric power generation system (1) of the first embodiment.

[0141] In addition, in the hydroelectric power generation system (1) of embodiment 3, the control unit (100) controls the power consumer (17) so that the power consumer (17) consumes power pulsations that exceed a threshold value (Pth) in the third power (P3), which is power in the DC unit (15) and is obtained by combining the first power (P1) and the second power (P2).

[0142] In the above configuration, the power pulsation of the third power (P3) that exceeds the threshold value (Pth) is consumed by the power consumer (17), so that the pulsation of the third power (P3) can be suppressed.

[0143] (Modification 1 of Embodiment 3) As shown in Fig. 15, in the hydroelectric power generation system (1) of the third embodiment, a "power consumer (17)" may be provided for each of the first converter (12) and the second converter (14). In this case, the power consumption process may include a first power consumption process for consuming a first power (P1) and a second power consumption process for consuming a second power (P2). The first power consumption process and the second power consumption process are performed in parallel with each other.

[0144] In the first power consumption process, the control unit (100) controls the power consumer (17) corresponding to the first converter (12) so that power pulsation exceeding a first threshold, in the first power (P1) obtained by the first converter (12), is consumed by the “power consumer (17) provided for the first converter (12).”

[0145] In the second power consumption process, the control unit (100) controls the power consumer (17) corresponding to the second converter (14) so ​​that the power pulsation exceeding the second threshold, in the second power (P2) obtained by the second converter (14), is consumed by the “power consumer (17) provided for the second converter (14).”

[0146] (Modification 2 of Embodiment 3) Furthermore, in the hydroelectric power generation system (1) of embodiment 3, if the relationship between the “rotation angle of the first generator (11) (or the rotation angle of the second generator (13))” and the “excess value (a value obtained by subtracting the threshold value (Pth) from the instantaneous value of the third power (P3))” is determined in advance (or is determined during operation), the control unit (100) may control the on / off of the switch (17b) of the power consumer (17) in accordance with the rotation angle of the first generator (11) (or the rotation angle of the second generator (13)) based on the relationship.

[0147] (Embodiment 4) The hydroelectric power generation system (1) of the fourth embodiment differs from the hydroelectric power generation system (1) of the first embodiment in the processing by the control unit (100). The other configurations and processing of the hydroelectric power generation system (1) of the fourth embodiment are the same as those of the hydroelectric power generation system (1) of the first embodiment.

[0148] In the hydroelectric power generation system (1) of the fourth embodiment, the control unit (100) performs torque correction processing in addition to the processing performed by the control unit (100) of the first embodiment.

[0149] In the torque correction process, the control unit (100) derives a first correction torque for reducing the torque ripple of the first generator (11) based on the rotation angle of the first generator (11). Then, the control unit (100) controls the torque of the first generator (11) based on the first correction torque.

[0150] In the torque correction process, the control unit (100) derives a second correction torque for reducing the torque ripple of the second generator (13) based on the rotation angle of the second generator (13). Then, the control unit (100) controls the torque of the second generator (13) based on the second correction torque.

[0151] For example, as shown in Fig. 16, the control unit (100) detects the torque of the first generator (11) for at least one cycle and derives the average value of the detected torque. Next, the control unit (100) sets the torque obtained by subtracting the "average torque value" from the "torque of the first generator (11) for one cycle" as the "first correction torque of the first generator (11) for one cycle."

[0152] Next, the control unit (100) stores a first torque correction value representing "the first correction torque of the first generator (11) for one cycle" in the storage unit (101). The first torque correction value is prepared for each rotation angle of the first generator (11). Then, the control unit (100) repeatedly performs the following process.

[0153] The control unit (100) derives a first torque command value indicating a torque required of the first generator (11) based on a predetermined torque derivation condition. Examples of the torque derivation condition include a condition that torque is derived so as to reduce the deviation between the rotation speed of the first generator (11) and the first rotation speed (target rotation speed), a condition that torque is derived so as to reduce the deviation between the flow rate of the fluid flowing through the first flow path (2a) and the first flow rate (target flow rate), and a condition that torque is derived from the target flow rate and a system loss curve (see FIG. 5).

[0154] Next, the control unit (100) detects the rotation angle of the first generator (11) and reads out a first torque correction value corresponding to the detected rotation angle of the first generator (11) from the storage unit (101). Next, the control unit (100) corrects the first torque command value based on the read-out first torque correction value, thereby deriving a first torque determination value. Examples of correction of the first torque command value based on the first torque correction value include adding the first torque correction value to the first torque command value and multiplying the first torque command value by the first torque correction value. Then, the control unit (100) controls the torque of the first generator (11) based on the first torque determination value.

[0155] The torque control of the second generator (13) by the control unit (100) is similar to the torque control of the first generator (11) by the control unit (100). Specifically, the torque control of the second generator (13) corresponds to control in which the “first torque command value,” “first correction torque,” ​​“first torque correction value,” and “first torque determination value” of the torque control of the first generator (11) are replaced with “second torque command value,” “second correction torque,” ​​“second torque correction value,” and “second torque determination value,” respectively.

[0156] [Effects of the fourth embodiment] The hydroelectric power generation system (1) of the fourth embodiment can achieve the same effects as those of the hydroelectric power generation system (1) of the first embodiment.

[0157] Furthermore, in the hydroelectric power generation system (1) of embodiment 4, the control unit (100) derives a first correction torque for reducing the torque ripple of the first generator (11) based on the rotation angle of the first generator (11), and controls the torque of the first generator (11) based on the first correction torque.

[0158] In the above configuration, the torque of the first generator (11) is controlled based on the first correction torque, thereby reducing the torque ripple of the first generator (11), thereby suppressing pulsation in the third power (P3).

[0159] Furthermore, in the hydroelectric power generation system (1) of embodiment 4, the control unit (100) derives a second correction torque for reducing the torque ripple of the second generator (13) based on the rotation angle of the second generator (13), and controls the torque of the second generator (13) based on the second correction torque.

[0160] In the above configuration, the torque of the second generator (13) is controlled based on the second correction torque, thereby reducing the torque ripple of the second generator (13), thereby suppressing the pulsation in the third power (P3).

[0161] (Other embodiments) In the above description, the following configuration or processing may be performed.

[0162] The first generator (11) and the second generator (13) may have different specifications. Specifically, the least common multiple of the number of poles and the number of slots of the second generator (13) may be different from the least common multiple of the number of poles and the number of slots of the first generator (11). In this case, the rotation speed of the first generator (11) may be the same as the rotation speed of the second generator (13).

[0163] The number of generators provided in the hydroelectric power generation system 1 may be three or more. Similarly, the number of converters provided in the hydroelectric power generation system 1 and connected to the generators and the DC unit 15 may be three or more.

[0164] The second flow path (2b) may be a flow path independent of the first flow path (2a). For example, the second flow path (2b) may be a flow path that does not branch off from the first flow path (2a) or a flow path that does not merge with the first flow path (2a).

[0165] The control device 10 may be applied to other power generation systems that utilize energy other than hydraulic power, such as a wind power generation system that includes a wind turbine, or a hybrid power generation system that includes both a hydraulic turbine and a wind turbine.

[0166] Although the embodiments and modifications have been described, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above-described embodiments, modifications, and other embodiments may be combined or substituted as appropriate. [Industrial Applicability]

[0167] INDUSTRIAL APPLICABILITY As described above, the present disclosure is useful as a power generation system control device, a power generation system, and a hydroelectric power generation system. [Explanation of symbols]

[0168] 1 Hydroelectric power generation system (power generation system) 2 Flow path 2a First flow path 2b Second flow path 3 Water tank 4. Water distribution target 5 Power system 10 Control device (control device for power generation system) 11 First Generator 12 First converter 13 Second Generator 14 Second converter 15 DC section 16 inverters 17 Power consumers 21 1st Fluid Machine 22 1st adjustment mechanism 23 2nd fluid machine 24 Second adjustment mechanism 100 control section 101 Storage section P1 First Power Station P2 2nd power P3 3rd power

Claims

1. A control device for a power generation system comprising a first generator (11), a first converter (12) that converts the power generated by the first generator (11) into a first power (P1) and supplies it to a DC section (15), a second generator (13), and a second converter (14) that converts the power generated by the second generator (13) into a second power (P2) and supplies it to the DC section (15), a control unit (100) that controls the first generator (11) so that some or all of the peak times of a plurality of pulsations included in the first power (P1) do not coincide with the peak times of a plurality of pulsations included in the second power (P2); the control unit (100) controls the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed; a product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from a product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the rotation speed of the second generator (13); The power generation system includes: a first fluid machine (21) provided in a first flow path (2a) through which a fluid flows and configured to drive the first generator (11); a first adjustment mechanism (22) that is provided in series with the first fluid machine (21) in the first flow path (2a) and is capable of adjusting the flow rate of a fluid flowing through the first flow path (2a); The control unit (100) controls the first adjusting mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes a first flow rate. Control device for power generation system.

2. The control device for a power generation system according to claim 1, The control unit (100) when the rotation speed of the first generator (11) changes in a direction in which the flow rate of the fluid flowing through the first flow path (2 a) increases, the first adjustment mechanism (22) is controlled so that the flow rate of the fluid flowing through the first flow path (2 a) decreases; When the rotation speed of the first generator (11) changes in a direction in which the flow rate of the fluid flowing through the first flow path (2a) decreases, the first adjustment mechanism (22) is controlled so that the flow rate of the fluid flowing through the first flow path (2a) increases. Control device for power generation system.

3. A control device for a power generation system comprising a first generator (11), a first converter (12) that converts the power generated by the first generator (11) into a first power (P1) and supplies it to a DC section (15), a second generator (13), and a second converter (14) that converts the power generated by the second generator (13) into a second power (P2) and supplies it to the DC section (15), a control unit (100) that controls the first generator (11) so that some or all of the peak times of a plurality of pulsations included in the first power (P1) do not coincide with the peak times of a plurality of pulsations included in the second power (P2); The control unit (100) controlling the first generator (11) so that the rotation speed of the first generator (11) becomes a first rotation speed; controlling the second generator (13) so that the rotation speed of the second generator (13) becomes a second rotation speed; a product of the least common multiple of the number of poles and the number of slots of the first generator (11) and the first rotation speed is different from a product of the least common multiple of the number of poles and the number of slots of the second generator (13) and the second rotation speed; The power generation system includes: a first fluid machine (21) provided in a first flow path (2a) through which a fluid flows and configured to drive the first generator (11); a first adjustment mechanism (22) that is provided in series with the first fluid machine (21) in the first flow path (2a) and is capable of adjusting the flow rate of a fluid flowing through the first flow path (2a); a second fluid machine (23) provided in a second flow path (2b) through which a fluid flows and configured to drive the second generator (13); a second adjustment mechanism (24) that is provided in series with the second fluid machine (23) in the second flow path (2b) and is capable of adjusting the flow rate of fluid flowing through the second flow path (2b); The second flow path (2b) merges with the first flow path (2a), The control unit (100) controls the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) becomes a target flow rate. Control device for power generation system.

4. The control device for a power generation system according to claim 3, The control unit (100) controlling the first adjustment mechanism (22) or the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) decreases when the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) increases; When the sum of the flow rate of the fluid flowing through the first flow path (2a) and the flow rate of the fluid flowing through the second flow path (2b) decreases, the first adjustment mechanism (22) or the second adjustment mechanism (24) is controlled so that the flow rate of the fluid flowing through the first flow path (2a) or the flow rate of the fluid flowing through the second flow path (2b) increases. Control device for power generation system.

5. The control device for a power generation system according to claim 3, The control unit (100) controlling the first adjustment mechanism (22) so that the flow rate of the fluid flowing through the first flow path (2a) becomes a first flow rate; controlling the second adjustment mechanism (24) so ​​that the flow rate of the fluid flowing through the second flow path (2b) becomes a second flow rate; the sum of the first flow rate and the second flow rate is the target flow rate; The ratio between the first flow rate and the second flow rate is the same as the ratio between the first rotation speed and the second rotation speed. Control device for power generation system.

6. A control device for a power generation system including a first generator (11), a first converter (12) that converts electric power generated by the first generator (11) into a first electric power (P1) and supplies the first electric power to a DC section (15), a second generator (13), and a second converter (14) that converts electric power generated by the second generator (13) into a second electric power (P2) and supplies the second electric power to the DC section (15), a control unit (100) that controls the first generator (11) so that some or all of the peak times of a plurality of pulsations included in the first power (P1) do not coincide with the peak times of a plurality of pulsations included in the second power (P2); the power generation system includes a power consumer (17); The control unit (100) controls the power consumer (17) so that power pulsation exceeding a threshold value (Pth) in a third power (P3) that is power in the DC unit (15) and is obtained by combining the first power (P1) and the second power (P2) is consumed by the power consumer (17). Control device for power generation system.

7. a first generator (11); a first converter (12) that converts the electric power generated by the first generator (11) into a first electric power (P1) and supplies the first electric power to a DC section (15); a second generator (13); a second converter (14) that converts the electric power generated by the second generator (13) into second electric power (P2) and supplies the second electric power (P2) to the DC section (15); a control device; The control device is a control device for a power generation system according to any one of claims 1 to 6. Power generation system.

8. a first generator (11); a first converter (12) that converts the electric power generated by the first generator (11) into a first electric power (P1) and supplies the first electric power to a DC section (15); a second generator (13); a second converter (14) that converts the electric power generated by the second generator (13) into second electric power (P2) and supplies the second electric power (P2) to the DC section (15); a control unit (100) that controls the first generator (11) so that some or all of the peak times of the plurality of pulsations included in the first power (P1) do not coincide with the peak times of the plurality of pulsations included in the second power (P2); a first fluid machine (21) provided in a first flow path (2a) through which a fluid flows and configured to drive the first generator (11); a first adjustment mechanism (22) that is provided in series with the first fluid machine (21) in the first flow path (2a) and is capable of adjusting the flow rate of a fluid flowing through the first flow path (2a); a second fluid machine (23) provided in a second flow path (2b) through which a fluid flows and configured to drive the second generator (13); a second adjustment mechanism (24) that is provided in series with the second fluid machine (23) in the second flow path (2b) and is capable of adjusting the flow rate of the fluid flowing through the second flow path (2b). Hydroelectric power generation system.

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