Electric power generation device

Abstract

Provided is an electric power generation device that makes it possible to output a high voltage direct electric current while suppressing a ground voltage of a generator and a rectifier circuit including a stator coil or the like. The electric power generation device comprises: a generator 60 that outputs a plurality of three-phase alternating electric currents; a plurality of three-phase rectification circuits 82; and a plurality of insulated step-up DC / DC converters 87. Each three-phase rectifier circuit 82 has a three-phase AC input end 84 and a DC output end 85, and one three-phase alternating electric current is input into the three-phase AC input end 84 of each three-phase rectifier circuit 82. DC electric power that is output from the DC output end 85 of at least one three-phase rectifier circuit 82 among the plurality of three-phase rectifier circuits 82 is input into a converter input end 93 of each insulated step-up DC / DC converter 87. A converter output end 94 of each of the insulated step-up DC / DC converters 87 is connected in series with the other converter output ends 94.

Description

power generation equipment

[0001] The present invention relates to a power generating device, and more particularly to a relatively large power generating device that generates electricity by utilizing hydrodynamic forces such as wind power and tidal power.

[0002] In recent years, the blades of power generation devices that utilize wind or tidal power have become larger, and as a result, the generators in these power generation devices have also become larger in size, exceeding 10 m, and their output has also increased.

[0003] Since offshore wind and tidal power generation facilities are installed far from land, the electricity they generate is usually transmitted through the ocean. In this case, high-voltage, high-output DC transmission is desirable due to the risk of leakage current caused by ground capacitance and the need to connect the electricity to the grid after receiving it at the land-based facility.

[0004] For example, a wind power generation system described in Patent Document 1 uses a three-phase transformer to boost three-phase AC power from a synchronous generator driven by a wind turbine, and then rectifies the power with an AC / DC rectifier made up of diodes. A plurality of AC / DC rectifiers, i.e., diodes, are connected in series, and the generated high-voltage DC power is transmitted via an HVDC (high-voltage direct current) transmission cable.

[0005] Furthermore, the wind power generation system described in Patent Document 2 includes multiple generators that output three-phase AC current. The three-phase AC current from each generator is rectified by a three-phase rectifier circuit composed of diodes, then DC / DC converted by a DC / DC converter, and output to a grid circuit. In this wind power generation system, the three-phase AC currents from each generator are output out of phase with each other. This distributes and flattens the torque pulsation of the generators, thereby reducing vibrations generated in the wind turbine's mechanical components.

[0006] JP-T-2003-511997 A JP-A-2007-174733 A

[0007] In the configuration of Patent Document 1, a high voltage is applied to the AC / DC rectifier. This increases the rectifier's voltage to ground, requiring the rectifier and its terminals to have high insulation, resulting in an increase in the size of the equipment. Furthermore, when attempting to output high-voltage DC, for example, several tens of kV, to a system circuit using the configuration of Patent Document 2, even if a DC / DC transformer can boost the voltage to a certain extent, a high voltage of at least several kV is applied to the three-phase AC circuit composed of diodes, and a similar high voltage is also applied to the stator coils of each generator. This increases the voltage to ground of the three-phase rectifier circuit and stator coils, requiring a configuration with high insulation, resulting in an increase in the size of the equipment.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a power generating device that can output high voltage DC while suppressing the voltage to ground of the generator and rectifier circuit, including the stator coil and the like.

[0009] That is, the present invention provides a power generating device comprising: a generator that outputs a plurality of polyphase ACs; a plurality of polyphase rectifier circuits, each having a polyphase AC input terminal and a DC output terminal, and each having a corresponding one of the polyphase ACs as input to the polyphase AC input terminal of the polyphase rectifier circuit; and a plurality of isolated step-up DC / DC converters, each having a converter input terminal to which DC power output from the DC output terminal of at least one of the plurality of polyphase rectifier circuits is input, and a converter output terminal, and each converter output terminal is connected in series to the other converter output terminals.

[0010] This power generation device has multiple isolated step-up DC / DC converters connected in series, allowing it to output high-voltage DC. Meanwhile, the generator and multi-phase rectifier circuit are electrically isolated from the high-voltage DC, allowing their voltage to ground to be kept low. This simplifies the insulation of the terminals and coil ends of the generator's coils, enabling it to be made smaller and less expensive. It also allows the rectifier circuit to be constructed using general-purpose elements, making the entire device less expensive.

[0011] Furthermore, at least one of the plurality of isolated step-up DC / DC converters can be configured to control the voltage at the converter input terminal, and when the output of the generator is equal to or lower than a predetermined threshold output, the at least one isolated step-up DC / DC converter can reduce the voltage at the converter input terminal.

[0012] Furthermore, at least one of the plurality of isolated step-up DC / DC converters is a bidirectional isolated step-up DC / DC converter, and at least one of the multi-phase rectifier circuits connected to at least one of the bidirectional isolated step-up DC / DC converters is a multi-phase inverter, and the multi-phase inverter converts DC power supplied via the bidirectional isolated step-up DC / DC converter into multi-phase AC power and supplies the AC power to the generator, thereby driving the generator.

[0013] Furthermore, the isolated step-up DC / DC converter connected to the position where the voltage is lowest among the plurality of isolated step-up DC / DC converters is a bidirectional isolated step-up DC / DC converter, and at least one of the multi-phase rectifier circuits connected to the isolated step-up DC / DC converter connected to the position where the voltage is lowest is a multi-phase inverter, and the multi-phase inverter converts DC power supplied via the bidirectional isolated step-up DC / DC converter into multi-phase AC power and supplies the AC power to the generator, thereby driving the generator.

[0014] Furthermore, the plurality of polyphase rectifier circuits may be configured to form a plurality of sets of polyphase rectifier circuit groups each including two or more polyphase rectifier circuits, each set of polyphase rectifier circuit groups having a single composite DC output terminal formed by interconnecting the DC output terminals of the plurality of polyphase rectifier circuits included in that set of polyphase rectifier circuit groups, and the converter input terminal of each isolated step-up DC / DC converter may be connected to the composite DC output terminal of a corresponding set of polyphase rectifier circuit groups among the plurality of sets of polyphase rectifier circuit groups.

[0015] Further, the plurality of polyphase ACs are a plurality of three-phase ACs, and the plurality of polyphase rectifier circuits are a plurality of three-phase rectifier circuits; the generator has a stator having a plurality of stator coils arranged in a ring shape, and a rotor having a plurality of magnetic poles arranged in a ring shape facing the stator coil; the plurality of stator coils form a plurality of three-phase coils, and the plurality of three-phase coils form a plurality of three-phase coil pairs each consisting of two three-phase coils of the same phase, forming a plurality of sets of three-phase coil groups each including a plurality of three-phase coil pairs, the plurality of three-phase coil pairs included in each set of three-phase coil groups being connected to a plurality of three-phase rectifier circuits included in one set of three-phase rectifier circuit groups out of the plurality of sets of three-phase rectifier circuit groups, and the plurality of magnetic poles can be arranged so that the plurality of three-phase coil pairs included in each set of three-phase coil groups output three-phase ACs that are out of phase with each other.

[0016] Furthermore, the stator coils are formed by concentrated winding, the number of the magnetic poles and the stator coils is poles:stator coils=2N((6n±1):6n) (where N is a natural number equal to or greater than 2, and n is a power of 2 including 1), the number of the plurality of isolated step-up DC / DC converters and the number of the plurality of three-phase coil groups is N, and the number of three-phase coil pairs included in each three-phase coil group can be 2n.

[0017] Furthermore, the voltage generated between the generator and the converter input terminal of each isolated step-up DC / DC converter can be 400 V or less, and the voltage generated at the converter output terminal of each isolated step-up DC / DC converter can be 1.2 kV or more.

[0018] The wind turbine may also include a shaft base connected to the generator and a rotary wind turbine fixed to the shaft base, and the generator may generate electricity by rotating the shaft base using wind force received by the rotary wind turbine.

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power generating device according to the present invention will now be described with reference to the accompanying drawings.

[0020] 1 is an explanatory diagram of the overall configuration of a power generating device according to a first embodiment of the present invention. FIG. 1 is an enlarged view of part II of FIG. 1. FIG. 2 is a perspective view of an example of a bearing module. FIG. 3 is a perspective view of an example of a rotor. FIG. 4 is a detailed explanatory diagram of the rotor of FIG. 5. FIG. 6 is a perspective view of an example of a stator (stator module). FIG. 7 is a perspective view of an example of a module assembly. (a) is a development view showing the positional relationship between magnetic poles and stator coils, (b) is an explanatory diagram showing the electrical angle phases of each coil, and (c) is an explanatory diagram showing the electrical connection relationship of the coils. FIG. 8 is an explanatory diagram showing the configuration of a power circuit. FIG. 9 is an explanatory diagram showing the configuration of a three-phase diode bridge. FIG. 10 is an explanatory diagram showing the configuration of an isolated step-up DC / DC converter. FIG. 11 is a graph showing the output voltage of a three-phase rectifier circuit. FIG. 11 is an explanatory diagram showing the configuration of another power circuit. FIG. 12 is an explanatory diagram showing the configuration of a three-phase inverter. FIG. 13 is an explanatory diagram of the configuration of magnetic poles and stator coils of a power generating device according to a second embodiment of the present invention. FIG. 14 is an explanatory diagram of the overall configuration of a power generating device according to a third embodiment of the present invention. (a) is a partial detailed view of the generator shown in FIG. 16, and (b) is a perspective view showing an example of an excitation core. (a) is a perspective view showing an example of a connecting unit, and (b) is a cross-sectional view of a state in which a rotor is fitted in the air gap of the connecting unit. An explanatory diagram showing an example of a case in which generators are installed in multiple stages. An explanatory diagram showing an example of a case in which the power generating device of the present invention is applied to a horizontal axis wind turbine power generating device. An explanatory diagram showing an example of a case in which the power generating device of the present invention is applied to a vertical axis tidal power generating device.

[0021] (Embodiment) An example of an embodiment of a power generation device of the present invention will be described with reference to the drawings. Here, a floating wind power generation device in which a vertical axis wind turbine is connected to the tip of a float will be described as an example. Below, the structure, operation, and effects of the power generation device of this embodiment will be described, followed by a description of modified examples of the power generation device.

[0022] <Structure of the power generation device of this embodiment> As an example, a floating wind turbine power generation device according to a first embodiment shown in Figure 1 includes a float 10, a shaft base 20, a rotary wind turbine 30, a bearing support 40, a bearing module 50, a generator 60, and a mooring line 70.

[0023] The float 10 is a member that floats on water, such as on the ocean or on a lake. The float 10 in this embodiment is a hollow cylinder, and contains ballast material inside to maintain balance. The ballast material can be water, iron, rocks, or other materials.

[0024] 2, a shaft base 20 is provided on the tip side (upper end side in the illustrated example) of the floating body 10. A rotary wind turbine 30 is connected to the tip side (upper end side in the illustrated example) of the shaft base 20.

[0025] The shaft base 20 is a portion on which the generator 60 and the bearing module 50 are mounted, and does not necessarily have to be an independent member. For example, the shaft base 20 may be a part of the floating body 10 or a part of the shaft 31 of the rotary wind turbine 30.

[0026] The rotary windmill 30 is a member that rotates when it receives wind (a force-receiving rotor). The rotary windmill 30 in this embodiment is a vertical-axis type that includes a shaft 31, a plurality of arms 32 that protrude laterally from the shaft 31, and blades 33 that are attached to the tips of the arms 32.

[0027] A bearing support 40 that supports the bearing module 50 is provided at a position outside the shaft base 20 around the axis and closer to the floating body 10. The bearing support 40 in this embodiment is disk-shaped, and has an insertion hole in its center through which the shaft base 20 can be inserted.

[0028] The bearing support 40 is provided on the outer side around the axis of the shaft base 20 inserted through the insertion hole. The bearing support 40 is fixed to the shaft base 20 at the periphery of the insertion hole, and is configured to rotate in the same direction as the shaft base 20 as the shaft base 20 rotates.

[0029] The bearing module 50 is a member that supports the stator 62. In a broader sense, the bearing module 50 is a member that supports the generator 60 that includes the stator 62 and the rotor 61. That is, the bearing module 50 is a member that directly supports the stator 62 and indirectly supports the rotor 61 via the bearing support 40 and the shaft base 20. As shown in FIG. 3 , the bearing module 50 of this embodiment includes a bearing base 51, a first load receiver 52, and a second load receiver 53.

[0030] The bearing base 51 is a member that serves as the base of the bearing module 50. The bearing base 51 is disposed around the axis of the shaft base 20 on the outer side so as not to rotate together with the shaft base 20. The bearing base 51 in this embodiment has a triangular shape in a plan view, and is provided with mooring line attachment portions 51a that protrude outward at each corner.

[0031] The mooring line attachment portion 51 a has locking holes 51 b. One end of a mooring line 70 is attached to each locking hole 51 b. The other end of each mooring line 70 has an anchor (not shown) that is fixed to the seabed or lakebed at the installation location.

[0032] An insertion hole through which the shaft base 20 can be inserted is provided in the center of the bearing base 51. A plurality of first load receivers 52 are provided around the periphery of the insertion hole of the bearing base 51. The first load receivers 52 are members that receive a load (radial load) in a first direction (horizontal direction in the illustrated example) applied from the shaft base 20, and are composed of a group of a plurality of horizontal rollers.

[0033] The second load receiving body 53 is a member that receives a load (axial load) in the second direction (vertical direction in the illustrated example) applied from the bearing support body 40, and is composed of a group of multiple vertical rollers. Specifically, one vertical roller is provided near the base of each of the three mooring rope attachment portions 51 a of the bearing base 51.

[0034] The bearing module 50 of this embodiment presses down (supports from above) the float 10 and the shaft base 20 and bearing support 40 connected to it to prevent them from floating up due to the buoyancy of the float 10 via the second load receiver 53, and holds the shaft base 20 horizontally via the first load receiver 52 to prevent the float 10 and shaft base 20 from moving horizontally.

[0035] Furthermore, the bearing module 50 holds the stator 62 so that the stator 62 does not rotate due to torque generated in the stator 62 as the shaft base 20 and the rotor 61 rotate. When the rotary wind turbine 30 receives wind, a horizontal force is applied to the bearing module 50 via the shaft base 20 connected to the rotary wind turbine 30.

[0036] Furthermore, when the rotary wind turbine 30 rotates, torque is applied to the bearing module 50 via the stator 62. The mooring lines 70 fix the bearing module 50 to the seabed to limit movement of the bearing module 50 that is subjected to these forces.

[0037] Furthermore, the first load receiver 52 and the second load receiver 53 rotatably support the shaft base 20 and the rotary wind turbine 30 and floating body 10 fixed thereto relative to the fixed bearing module 50 .

[0038] The generator 60 is a device that generates electricity using the rotational force generated by the rotary wind turbine 30. The generator 60 includes a rotor 61 and a stator 62 that are spaced apart in the axial direction of the shaft base 20.

[0039] The rotor 61 is a field magnet that generates a magnetic field. As shown in Figures 4 and 5, the rotor 61 of this embodiment includes a rotor base 61a and a permanent magnet 61b attached to the rotor base 61a. The rotor base 61a of this embodiment is disk-shaped and has an insertion hole at its center through which the shaft base 20 can be inserted.

[0040] The rotor base 61a is provided on the outer side around the axis of the shaft base 20 inserted through the insertion hole. The rotor base 61a is fixed to the shaft base 20 at the periphery of the insertion hole, and is configured to rotate in the same direction as the shaft base 20 as the shaft base 20 rotates.

[0041] In this embodiment, multiple bar-shaped magnets are used as the permanent magnets 61b. The multiple bar-shaped magnets are arranged radially from the center point of the shaft base 20. Existing neodymium magnets or the like can be used as the permanent magnets 61b. The multiple permanent magnets 61b are detachably mounted on the rotor base 61a.

[0042] The stator 62 is an armature that generates electricity in the magnetic field created by the permanent magnets 61b. The stator 62 is provided on the outer side of the shaft base 20 around the axis and facing the rotor 61. The stator 62 is provided at an interval from the rotor 61 in the axial direction of the shaft base 20.

[0043] 6, the stator 62 of this embodiment includes a plurality of stator modules 62a arranged in a ring shape. The stator modules 62a herein refer to the components (individual pieces) that make up the stator 62.

[0044] The stator module 62a is made up of a plurality of module components 62b arranged side by side. The stator module 62a made up of the plurality of module components 62b is a rectangular parallelepiped structure, and when arranged in a ring shape, a gap that is approximately trapezoidal in plan view is formed between adjacent stator modules 62a.

[0045] As shown in FIG. 7, each module structure 62b constituting the stator module 62a includes a stator core 62c and a concentrated winding stator coil 62d wound around the stator core 62c.

[0046] In this embodiment, the stator core 62c is a long iron core that is T-shaped in end view, and the stator coil 62d is made of copper windings, although other materials may be used for the stator core 62c and the stator coil 62d.

[0047] The multiple stator modules 62a are detachably held by a stator holder 63. In this embodiment, the stator holder 63 is a disk-shaped member having an insertion hole in the center through which the shaft base 20 can be inserted. The stator holder 63 is supported by the bearing module 50 with the shaft base 20 inserted into the insertion hole.

[0048] In this embodiment, the stator module 62a can be inserted and removed (attached and detached) by sliding it radially of the stator holder 63. As described above, in this embodiment, when the stator modules 62a are arranged in a ring shape, a gap that is approximately trapezoidal in plan view (a dimensional margin) is formed between adjacent stator modules 62a, so that the stator modules can be easily removed radially.

[0049] - Relationship between magnetic poles and stator coils - The number of magnetic poles (permanent magnets) 61b and stator coils 62d is set to satisfy the following formula: Formula (1) Magnetic poles: Stator coils = 2N ((6n±1): 6n) where N is a natural number of 2 or greater, and n is a power of 2 including 1 (1, 2, 4, 8, 16, ...).

[0050] In this power generating device, the number of magnetic poles 61b is 2N (6n+1), where N=6 and n=2. Therefore, the number of magnetic poles 61b is 156, and the number of stator coils 62d is 144. As shown in FIGS. 6 and 7 , the stator cores 62c and the stator coils 62d are divided into six stator modules 62a, with 24 stator cores 62c and stator coils 62d forming one stator module 62a. Each stator module 62a is arranged in a hexagonal shape facing the magnetic poles 61b. Therefore, while the magnetic poles 61b are arranged in a circular ring shape, the stator coils 62d are arranged in a hexagonal ring shape.

[0051] The positional relationship between the magnetic poles 61b and the stator coils 62d at this time is as shown in the development view of Fig. 8(a). Fig. 8 shows only the stator coils 62d included in one stator module 62a and the magnetic poles 61b facing them, but the other stator modules 62a have a similar positional relationship. As described above, one stator module 62a includes 24 stator coils 62d, from the first coil to the 24th coil.

[0052] Facing the 24 stator coils 62d, 26 magnetic poles are arranged with alternating north and south poles. In the illustrated state, the first magnetic pole, which is the north pole, is located at a position facing the first coil. The magnetic pole 61b moves leftward relative to the stator coil 62d as viewed in the figure. The centers of the first coil and the first magnetic pole are aligned. At this time, the electrical angle phase of the electromotive force induced by the first coil is set to 0 degrees. The second magnetic pole, which is the south pole, is located at a position facing the second coil, but the centers of the second coil and the second magnetic pole are offset. In this embodiment, the ratio of the number of poles to the number of stator coils is 156:144, so the magnetic pole pitch τ ｍ and coil pitch τ ｃ is τ ｍ :τ ｃ Therefore, the center position of the second magnetic pole is τ ｍ × (156-144) / 144, that is, τ ｍ The phase difference between the first coil and the second coil is π×1 / 12. This is expressed in electrical angle phase as π×1 / 12, or 15 degrees. Note that the first coil faces the north pole while the second coil faces the south pole, but the first coil is clockwise while the second coil is counterclockwise. Therefore, the electromotive force induced in the second coil is 15 degrees out of phase with the electromotive force induced in the first coil. Similarly, the electromotive force induced in the third coil is 30 degrees out of phase with the electromotive force induced in the first coil. Furthermore, the electromotive force induced in the fourth coil is 45 degrees out of phase with the electromotive force induced in the first coil. The amounts of electrical angle phase difference between the other coils and the first coil are as shown in FIG. 8(b).

[0053] As shown in FIGS. 8(b) and 8(c), the first, fifth, and ninth coils form a first three-phase coil (U1, V1, W1). Similarly, the second, sixth, and tenth coils form a second three-phase coil (U2, V2, W2). The third, seventh, and eleventh coils form a third three-phase coil (U3, V3, W3). The fourth, eighth, and twelfth coils form a fourth three-phase coil (U4, V4, W4). The thirteenth, seventeenth, and twenty-first coils form a fifth three-phase coil (U5, V5, W5). The fourteenth, eighteenth, and twenty-second coils form a sixth three-phase coil (U6, V6, W6). The fifteenth, nineteenth, and twenty-third coils form a seventh three-phase coil (U7, V7, W7). The 16th coil, the 20th coil, and the 24th coil form an eighth three-phase coil (U8, V8, W8).

[0054] The first three-phase coil (U1, V1, W1) and the fifth three-phase coil (U5, V5, W5) have the same electrical angle phase and output in-phase three-phase AC. These first three-phase coil and the fifth three-phase coil are connected in parallel as shown in FIG. 8(c) to form one three-phase coil pair. Similarly, the second three-phase coil (U2, V2, W2) and the sixth three-phase coil (U6, V6, W6), which are in-phase, are connected in parallel to form one three-phase coil pair. The third three-phase coil (U3, V3, W3) and the seventh three-phase coil (U7, V7, W7), which are in-phase, are connected in parallel to form one three-phase coil pair. The fourth three-phase coil (U4, V4, W4) and the eighth three-phase coil (U8, V8, W8), which are in-phase, are connected in parallel to form one three-phase coil pair. The neutral wire of each three-phase coil pair is independent of the others. The three-phase coils constituting each three-phase coil pair may be connected in series.

[0055] <Configuration of Power Circuit> The power generation device includes a power circuit 80 shown in Fig. 9. As described above, four three-phase coil pairs 81-1 to 81-4 formed from 24 stator coils output power to a DC power distribution system 83 via three-phase rectifier circuits 82-1 to 82-4. Specifically, the first three-phase coil pair 81-1 is connected to a three-phase AC input terminal 84-1 of a first three-phase rectifier circuit 82-1, and the three-phase AC output from the first three-phase coil pair 81-1 is input to the first three-phase rectifier circuit 82-1 and rectified. The rectified current is output from a DC output terminal 85-1 of the first three-phase rectifier circuit 82-1. Similarly, the second to fourth three-phase coil pairs 81-2 to 81-4 are connected to three-phase AC input terminals 84-2 to 82-4 of second to fourth three-phase rectifier circuits 82-2 to 82-4, respectively, and rectified currents are output from DC output terminals 85-2 to 85-4 of the three-phase rectifier circuits 82-2 to 82-4. The DC output terminals 85-1 to 85-4 of the first to fourth three-phase rectifier circuits 82-1 to 82-4 are connected in parallel to form a single composite DC output terminal 86. Therefore, the powers output from the DC output terminals 85-1 to 85-4 of the first to fourth three-phase rectifier circuits 82-1 to 82-4 are combined at the composite DC output terminal 86. 9, for example, the first three-phase coil pair 81-1 outputs a three-phase AC signal obtained by combining three-phase AC signals from a three-phase coil (U1, V1, W1) and a three-phase coil (U5, V5, W5), but because the phases of both three-phase coils (U1, V1, W1) and (U5, V5, W5) are the same, the phases are shown as (U1, V1, W1) for convenience. The same applies to the three-phase AC signals of the other three-phase coil pairs 81-2 to 81-4.

[0056] Each of the three-phase rectifier circuits 82-1 to 82-4 is a diode bridge circuit in which six diodes are bridge-connected as shown in FIG. 10, and is an element formed as a single package.

[0057] As shown in Figure 9, an isolated step-up DC / DC converter 87 is connected to the composite DC output terminal 86. The isolated step-up DC / DC converter 87 can be configured, for example, as a dual active bridge (DAB) circuit as shown in Figure 11. A DAB circuit is a bidirectional isolated step-up DC / DC converter that has a bridge on each of the primary and secondary sides of a transformer and can convert power not only from the primary side to the secondary side but also from the secondary side to the primary side by controlling the phase of the primary side and the phase of the secondary side. Note that the isolated step-up DC / DC converter 87 does not necessarily have to be a bidirectional isolated step-up DC / DC converter like a DAB circuit, and can be any of various DC / DC converters known in the art.

[0058] This isolated step-up DC / DC converter 87 boosts the output from the three-phase rectifier circuit 82 and outputs it to the DC power distribution system 83. The isolated step-up DC / DC converter 87 of this embodiment boosts 400 V to 1.2 kV and outputs it. Of course, the input voltage and output voltage of the isolated step-up DC / DC converter 87 can also be other magnitudes.

[0059] 12, the current 88-1 output from the DC output terminal 85-1 of the first three-phase rectifier circuit 82-1 is accompanied by a rectification ripple that fluctuates in a 60-degree cycle. The current 88-2 output from the DC output terminal 85-2 of the second three-phase rectifier circuit 82-2 is also accompanied by a rectification ripple that fluctuates in a 60-degree cycle. However, because the three-phase AC (U2, V2, W2) output from the second three-phase coil pair 81-2 is shifted in phase by 15 degrees from the three-phase AC (U1, V1, W1) output from the first three-phase coil pair 81-1, the current 88-2 output from the second three-phase rectifier circuit 82-2 has a rectification ripple that fluctuates in a 15-degree cycle with respect to the current 88-1 output from the first three-phase rectifier circuit 82-1. Similarly, the current 88-3 output from the third three-phase rectifier circuit 82-3 has a rectification ripple that fluctuates periodically with a 30-degree phase shift, and the current 88-4 output from the fourth three-phase rectifier circuit 82-4 has a rectification ripple that fluctuates with a 45-degree phase shift. When currents 88-1 to 88-4, each with a rectification ripple that is 15 degrees out of phase with each other, are connected in parallel and combined, a combined DC current 89 is obtained, as shown in FIG. 12. The ripple in the combined DC current 89 is significantly reduced, resulting in an output that is closer to DC. The average voltage is also increased. As a result, the output at the combined DC output terminal 86 has less ripple and a higher average output. The effect of reducing ripple can also be achieved by connecting the DC output terminals 85-1 to 85-4 of the three-phase rectifier circuits 82-1 to 82-4 in series.

[0060] As shown in FIG. 9 , a smoothing capacitor 90 is disposed between the combined DC output terminal 86 and the isolated step-up DC / DC converter 87. This smoothing capacitor 90 charges when the voltage of the combined DC 89, which fluctuates due to rectification ripple, is high, and discharges when that voltage is low. This further reduces the ripple remaining in the combined DC 89, allowing a smoothed current with less ripple to be input to the isolated step-up DC / DC converter 87. Generally, the larger the voltage fluctuation, the larger the capacity of this smoothing capacitor 90. As described above, in this power generation device, the rectification ripple is significantly reduced by connecting and combining multiple voltages with out-of-phase rectification ripples, allowing the use of a capacitor with a relatively small capacity. This contributes to the miniaturization of the entire device.

[0061] As shown in FIG. 9 , this embodiment includes six isolated step-up DC / DC converters 87 connected in series. Furthermore, 192 stator coils 62d are provided, with 24 stator coils 62d included in one stator module 62a constituting one three-phase coil group 91, each of which includes four three-phase coil pairs 81-1 to 81-4. The four three-phase coil pairs 81-1 to 81-4 included in this one three-phase coil group 91 are configured to output three-phase AC currents that are shifted in phase by 15 degrees from one another. Similarly, another three-phase coil group (omitted in FIG. 9 ) is configured with another 24 stator coils 62d, each of which includes four three-phase coil pairs 81. The four three-phase coils included in this three-phase coil group are also configured to output three-phase AC currents that are shifted in phase by 15 degrees from one another. Similarly, four more three-phase coil groups (omitted in FIG. 9 ) are configured. In this way, a total of six three-phase coil groups 91 (24 three-phase coil pairs 81) are formed. The number of three-phase coil groups 91 is the same as N in formula (1), and the number of three-phase coil pairs 81 included in each group is the same as 2n.

[0062] The four three-phase coil pairs 81 included in one three-phase coil group 91 are each connected to a three-phase rectifier circuit 82. Therefore, the power circuit 80 is provided with 24 three-phase rectifier circuits 82, the same number as the three-phase coil pairs 81. Of the 24 three-phase rectifier circuits 82, four three-phase rectifier circuits 82 constitute one three-phase rectifier circuit group 92, for a total of six three-phase rectifier circuit groups 92.

[0063] Each set of three-phase rectifier circuit groups 92 has one composite DC output terminal 86 formed by interconnecting the DC output terminals 85 of the four (2n) three-phase rectifier circuits 82 included in that set of three-phase rectifier circuit groups 92. The power output from the DC output terminals 85 of the four three-phase rectifier circuits 82 in each set of three-phase rectifier circuit groups 92 is combined at the composite DC output terminal 86. A converter input terminal 93 of one isolated step-up DC / DC converter 87 is connected to each composite DC output terminal 86. In addition, a smoothing capacitor 90 is arranged between the composite DC output terminal 86 and the isolated step-up DC / DC converter 87.

[0064] As described above, the converter output terminals 94 of the six isolated step-up DC / DC converters 87 are connected in series with each other. In this embodiment, during normal operation, each isolated step-up DC / DC converter 87 is set to step-up 400 V to 1.2 kV. Therefore, 7.2 kV, which is six times 1.2 kV, is output to the DC distribution system 83. The number of isolated step-up DC / DC converters 87 is the same as N in equation (1).

[0065] By providing the isolated step-up DC / DC converter 87, the three-phase coil pair 81, the three-phase rectifier circuit 82, the smoothing capacitor 90, and their terminals can be electrically insulated from the DC power distribution system 83. Therefore, the ground voltage of the three-phase coil pair 81 (stator core 62c, stator coil 62d), the three-phase rectifier circuit 82, the smoothing capacitor 90, and the like can be set to a relatively low voltage of 400 V or less. In particular, when multiple isolated step-up DC / DC converters 87 are connected in series, the voltage of the DC power distribution system 83 can be increased to a high voltage (e.g., 7.2 kV), but the ground voltage of the three-phase coil pair 81, etc. can remain at 400 V or less regardless of the number of isolated step-up DC / DC converters 87 connected in series. This simplifies the insulation of the output terminals and coil ends of the stator coil 62d, enabling them to be made smaller and less expensive. Furthermore, since the three-phase rectifier circuit 82 can use general-purpose elements that are commercially available for general industrial use, the overall power generating device can be manufactured at low cost.

[0066] As in the power circuit 80′ shown in FIG. 13 , a three-phase rectifier circuit included in a three-phase rectifier circuit group 92′ connected to one of a plurality of isolated step-up DC / DC converters 87 may be a three-phase inverter 95. This three-phase inverter 95 may be a commonly used voltage-source inverter (VSI) as shown in FIG. 14 . This three-phase inverter 95 has six transistors, and by controlling the switching timing of each transistor, any three-phase AC current can be output from an output terminal 96. The three-phase AC currents output from each three-phase inverter 95 to each three-phase coil pair 81 of the three-phase coil group 91′ may be shifted in phase by 15 degrees from each other. Specifically, with respect to the three-phase AC output from the first three-phase inverter 95-1, the three-phase AC output from the second three-phase inverter 95-2 can be shifted in phase by 15 degrees, the three-phase AC output from the third three-phase inverter 95-3 can be shifted in phase by 30 degrees, and the three-phase AC output from the fourth three-phase inverter 95-4 can be shifted in phase by 45 degrees. This phase shift is the same as the phase shift of the three-phase AC output from each three-phase coil pair 81 during power generation. By shifting the phases in this way, torque ripples caused by each three-phase AC can be mutually canceled or smoothed, thereby reducing vibrations generated in the rotary wind turbine 30, the shaft base 20, etc.

[0067] In particular, in large wind power generators, wind power cannot be effectively converted into rotational force until the rotary wind turbine 30 rotates at a certain speed or higher, resulting in inefficient power generation. In such cases, DC power is supplied to the three-phase inverters 95 via the bidirectional isolated step-up DC / DC converter 87, and each three-phase inverter 95 converts the DC power into three-phase AC and supplies it to each three-phase coil pair 81. This provides rotational torque to the rotor 61, driving it to rotate. This rotational force assists the rotation of the shaft base 20 and the rotary wind turbine 30 connected to the rotor 61. When the rotation of the rotary wind turbine 30 reaches a certain speed or higher, the power supply from the three-phase inverters 95 to the three-phase coil pairs 81 is stopped. After this, each three-phase inverter 95 stops switching its transistors and functions as a rectifier circuit similar to the three-phase rectifier circuit 82 consisting of a diode bridge. Therefore, the three-phase AC generated by the three-phase coil pair 81 connected to the three-phase inverter 95 is rectified by the three-phase inverter 95 and output to the isolated step-up DC / DC converter 87'.

[0068] The three-phase inverter 95 is connected to an isolated step-up DC / DC converter 87' that is connected to the isolated step-up DC / DC converter 87' at the position where the lowest voltage is obtained among the plurality of series-connected isolated step-up DC / DC converters 87. In the above embodiment, all four three-phase rectifier circuits constituting the three-phase rectifier circuit group 92' connected to this isolated step-up DC / DC converter 87' are three-phase inverters 95. However, if there is a margin in the driving capacity of each three-phase inverter 95, only three, two, or one three-phase rectifier circuit 82 may be used as the three-phase inverter 95. Alternatively, if the driving capacity of only four three-phase inverters 95 is insufficient, three-phase rectifier circuits 82 included in other three-phase rectifier circuit groups 92 may also be used as three-phase inverters 95. The number of three-phase rectifier circuits 82 to be used as the three-phase inverters 95 can be determined appropriately taking into account various conditions, such as the size of the rotary wind turbine 30 and the amount of power supplied to the three-phase inverter 95. Furthermore, it is not necessary that the three-phase rectifier circuit 82 connected to the isolated step-up DC / DC converter 87′ connected to the position where the voltage is lowest is a three-phase inverter 95, and the three-phase rectifier circuit 82 connected to the isolated step-up DC / DC converter 87 connected to another position may be configured as a three-phase inverter 95.

[0069] The isolated step-up DC / DC converter 87 is designed to boost 400 V to 1.2 kV during normal operation, but is capable of controlling the voltage at its converter input terminal 93. For example, if the output of the generator 60 is below a predetermined threshold output due to insufficient wind power or other reasons, the three-phase AC voltage output from each three-phase coil pair 81 may become lower than the voltage of the smoothing capacitor 90. This prevents the diodes of the three-phase rectifier circuit 82 from turning on, preventing power from being supplied to the isolated step-up DC / DC converter 87. In such a case, the isolated step-up DC / DC converter 87 reduces the voltage at its converter input terminal 93, turning on the diodes of the three-phase rectifier circuit 82 and allowing power to be supplied to the isolated step-up DC / DC converter 87. At this time, the isolated step-up DC / DC converter 87 increases the boost voltage so as to maintain 1.2 kV at the converter output terminal 94.

[0070] 15, in the power generating device according to the second embodiment of the present invention, 144 stator cores 62c and stator coils 62d are arranged in a circular ring shape facing the magnetic poles 61b. This corresponds to the case where N = 6 and n = 2 in equation (1). In this arrangement, the positional relationship between the magnetic poles 61b and the stator cores 62c and stator coils 62d is constant, so there is little disturbance in the three-phase AC output from the three-phase coil pairs 81, and the same output can be obtained except for the phase difference.

[0071] In a power generating apparatus according to a third embodiment of the present invention shown in FIG. 16, magnetic poles are formed by magnetic pole cores 61c excited by excitation cores 65a and field coils 65b, instead of permanent magnets.

[0072] The stator 62 of this embodiment includes a plurality of stator parts 62a (24 in this embodiment) arranged in a ring shape on a support base 67. The stator parts 62a here refer to the components (individual pieces) that make up the stator 62. As shown in Fig. 17, the stator part 62a includes a stator core 62c and a concentrated winding stator coil 62d wound around the stator core 62c. In this embodiment, an E-shaped core is used as the stator core 62c, and copper windings are used as the stator coil 62d.

[0073] The exciter 65 for exciting the magnetic pole core 61c is composed of a plurality of excitation cores 65a and a field coil 65b arranged in a ring shape. In this embodiment, the excitation core 65a is a rectangular parallelepiped member made of laminated steel plates. A recessed coil arrangement portion 65c into which the field coil 65b is accommodated is provided on the upper surface of the excitation core 65a. The field coil 65b is arranged in a position spanning the coil arrangement portions 65c of the plurality of excitation cores 65a arranged in a ring shape. The field coil 65b does not rotate but remains stationary within the coil arrangement portions 65c of the plurality of excitation cores 65a.

[0074] 18, the stator core 62c and the excitation core 65a in this embodiment are connected at one longitudinal end thereof by a connecting member 66 made of a non-magnetic material (hereinafter referred to as the "non-magnetic connecting member") to form a connecting unit U. The non-magnetic connecting member 66 can be fixed with fasteners such as bolts so that it can be attached to and detached from the stator core 62c and the excitation core 65a.

[0075] Between the connected stator part 62a and the excitation core 65a, a space G is provided that is large enough to accommodate the thickness of the rotor 61, which is made up of the rotor base 61a and the magnetic pole core 61c. When the rotor 61 is fitted into this space G, a first air gap G1 is formed between the rotor 61 and the stator 62, and a second air gap G2 is secured between the rotor 61 and the excitation body 65, as shown in FIG.

[0076] The magnetic flux generated by the field coil 65b passes through the excitation core 65a and then through the magnetic pole cores 61c, exciting the magnetic pole cores 61c. The 26 magnetic pole cores 61c arranged in a ring form claw poles, and are configured so that the polarity of the magnetic pole cores 61c at positions close to the stator core 62c differs from that of the adjacent magnetic pole cores 61c. In other words, the polarity of the magnetic pole cores 61c excited by the exciter 65 (excitation cores 65a, field coil 65b) alternates between north and south poles in the circumferential direction relative to the stator 62. The magnetic pole cores 61c rotate together with the rotor base 61a relative to the stator 62, but the polarity of each magnetic pole core 61c is maintained.

[0077] As described above, in this embodiment, the magnetic poles are formed by the field coil 65b and the magnetic pole core 61c, which is excited when a field current is supplied to the field coil 65b. In this case, the field current supplied to the field coil 65b may be stopped when the output of the generator 60 is below a predetermined threshold. Stopping the field current prevents the magnetic pole core 61c from being excited, reducing cogging torque and iron loss due to the magnetic poles. This makes it easier for the rotor 61 to rotate, allowing the rotary wind turbine 30 to rotate even in relatively weak winds. When the wind speed increases and reaches the cut-in wind speed, the supply of field current to the field coil 65b is started, and power generation begins. Because the field current has been stopped up to this point, the temperature of the field coil 65b is kept low. Therefore, it is possible to pass a large current through the field coil 65b for a short period of time. Therefore, when low-speed power generation begins, the field current is increased compared to normal operation to maximize the generated voltage. At the same time, the voltage at the converter input terminal is reduced by increasing the step-up ratio of the isolated step-up DC / DC converter 87. This makes it easier for the diodes in the three-phase rectifier circuit to be turned on, and makes it possible to generate power even when the rotary wind turbine 30 is rotating at a slower speed.

[0078] As described above, the power generating apparatus of this embodiment has 26 magnetic poles and 24 stator coils. This corresponds to the case where N = 2 and n = 1 in the above formula (1). This power generating apparatus also has power circuits similar to the power circuits 80, 80' shown in Figures 8 to 14. However, the number of three-phase coil pairs 81 included in one set of three-phase coil group 91 and the number of three-phase rectifier circuits 82 included in one set of three-phase rectifier circuit group 92 are both two, and the number of isolated step-up DC / DC converters 87 is two. Other configurations and characteristics of the power circuits are similar to those of the power circuits 80, 80'.

[0079] The configurations of the above-described embodiments are merely examples, and the configuration of the power generation device of the present application is not limited to the configurations of the above-described embodiments. The power generation device of the present application can be modified, such as by omitting, replacing, or adding components, to the extent that the intended purpose can be achieved. For example, the following modifications are envisioned.

[0080] The number of magnetic poles (permanent magnets 61b, magnetic pole cores 61c) and stator coils 62d can be changed as appropriate in accordance with equation (1). The number of three-phase coil pairs 81 included in one three-phase coil group 91 is 2n, and the phase difference between these three-phase coil pairs 81 is given by 30 / n. Therefore, as n increases, the number of three-phase coil pairs 81 included in one three-phase coil group 91 increases, the phase difference decreases, and the amplitude of the rectification ripple included in the output power rectified and combined by the three-phase rectifier circuit 82 decreases. Furthermore, the number of three-phase coil groups 91, and therefore the number of isolated step-up DC / DC converters 87, is N. Therefore, as N increases, the number of isolated step-up DC / DC converters 87 connected in series increases, and the final output voltage to the DC power distribution system 83 increases. Taking these characteristics into consideration, the values ​​of N and n in equation (1) can be changed as desired. In addition, in all of the above embodiments, the number of magnetic poles 61b in equation (1) is set to 2N(6n+1), so that the number of magnetic poles 61b is greater than the number of stator coils 62d, but the number of magnetic poles 61b can also be set to 2N(6n-1), so that the number of magnetic poles 61b is less than the number of stator coils 62d.

[0081] By determining the number of magnetic poles 61b and stator coils 62d in accordance with formula (1), it is possible to reduce rectification ripple, suppress vibration due to torque ripple, and reduce the capacitance of the smoothing capacitor 90, but it is not necessary to follow formula (1). Also, it is not necessary to connect a plurality of three-phase rectifier circuits and three-phase coils to one isolated step-up DC / DC converter.

[0082] The generator 60 may output multi-phase AC other than three phases, such as five or seven phases. That is, a multi-phase coil other than three phases may be used instead of a three-phase coil. In this case, the rectifier circuit may be a multi-phase rectifier circuit (a multi-phase diode bridge or a multi-phase inverter) that is suitable for the multi-phase coil.

[0083] In the above embodiment, the force-receiving rotating body is an example of a rotary wind turbine 30, but the force-receiving rotating body may be anything other than a rotary wind turbine 30 as long as it rotates by receiving the force of a fluid (gas or fluid), specifically, natural energy such as wind power or water power (including tidal power).

[0084] In the above embodiment, an example is shown in which one generator 60 is provided, but as shown in Fig. 19, two or more generators 60 may be provided in the axial direction of the shaft base 20. In this case, it is preferable that the two or more generators 60 are arranged so that the magnetic forces of the rotors 61 of adjacent generators 60 cancel each other out.

[0085] When two or more generators 60 are provided, the orientation of each generator 60 may be the same or opposite. Furthermore, when two or more generators 60 are provided, a bearing support 40 and a bearing module 50 may be provided for each generator 60, but it is also possible to provide the bearing support 40 and the bearing module 50 only for the generator 60 at the lowest stage, and omit these for the generators at the second stage and thereafter.

[0086] In the above embodiment, the rotary wind turbine 30 is a vertical axis type, but the rotary wind turbine 30 may be a horizontal axis type as shown in Figure 20. Also, the rotary wind turbine 30 may be a lift type or a drag type.

[0087] In the above embodiment, a floating wind power generation system in which the power generation system floats on the ocean is used as an example, but the power generation system of the present invention can also be configured as an on-water power generation system installed on water such as the sea or a lake, or as a land-based power generation system installed on land.

[0088] In the above embodiment, the power generation device is a floating vertical axis type wind turbine power generation device as an example, but the power generation device can also be configured as a floating vertical axis type tidal power generator as shown in Figure 21.

[0089] The embodiments disclosed in this application are merely examples and are not intended to limit the technical scope of the power generation device of the present invention. The technical scope of the power generation device of the present invention is defined by the claims. The technical scope of the present invention also includes equivalents to the claims.

[0090] The power generation device disclosed in the present application can be applied to various power generation devices, and in particular can be suitably used as a floating vertical axis type wind power generation device that floats on the ocean, such as on the sea or on a lake.

[0091] REFERENCE SIGNS LIST 10 Floating body 20 Shaft base 30 Rotating wind turbine (force-receiving rotating body) 31 Shaft 32 Arm 33 Blade 40 Bearing support 50 Bearing module 51 Bearing base 51a Mooring line attachment portion 51b Locking hole 52 First load receiver 53 Second load receiver 60 Generator 61 Rotor 61a Rotor base 61b Permanent magnet (magnetic pole) 61c Magnetic pole core (magnetic pole) 62 Stator 62a Stator module, stator part 62b Module constituent body 62c Stator core 62d Stator coil 63 Stator holder 65 Exciter 65a Excitation core 65b Field coil 65c Coil arrangement portion 66 Non-magnetic connecting member (connecting member) 67 Support base 70 Mooring line 80, 80' Power circuit 81 (81-1 to 81-4) Three-phase coil pair 82 (82-1 to 82-4) Three-phase rectifier circuit 83 DC distribution system 84 (84-1 to 84-4) Three-phase AC input terminal 85 (85-1 to 85-4) DC output terminal 86 Combined DC output terminal 87, 87' Isolated step-up DC / DC converter 88-1 to 88-4 Current 89 Combined DC 90 Smoothing capacitor 91, 91' Three-phase coil group 92, 92' Three-phase rectifier circuit group 93 Converter input terminal 94 Converter output terminal 95 (95-1 to 95-4) Three-phase inverter 96 Output terminal G Space G1 First air gap G2 Second air gap τ ｃ Coil pitch τ ｍ Pole pitch

Claims

1. A power generation device comprising: a generator that outputs a plurality of polyphase AC signals; a plurality of polyphase rectifier circuits, each having a polyphase AC input terminal and a DC output terminal, and each having a corresponding one of the polyphase AC signals input to the polyphase AC input terminal of the polyphase rectifier circuit; and a plurality of isolated step-up DC / DC converters, each having a converter input terminal to which DC power output from the DC output terminal of at least one of the plurality of polyphase rectifier circuits is input, and a converter output terminal, and each converter output terminal is connected in series to the other converter output terminals.

2. The power generation device according to claim 1, wherein at least one of the plurality of isolated step-up DC / DC converters is capable of controlling the voltage at the converter input terminal, and when the output of the generator is equal to or lower than a predetermined threshold output, the at least one isolated step-up DC / DC converter reduces the voltage at the converter input terminal.

3. The power generating device according to claim 1, wherein at least one of said plurality of isolated step-up DC / DC converters is a bidirectional isolated step-up DC / DC converter, and at least one of said multi-phase rectifier circuits connected to at least one of said bidirectional isolated step-up DC / DC converters is a multi-phase inverter, and said multi-phase inverter converts DC power supplied via said bidirectional isolated step-up DC / DC converter into multi-phase AC power and supplies the converted AC power to said generator, thereby driving said generator.

4. The power generating device according to claim 1, wherein the isolated boost DC / DC converter connected to the position of the plurality of isolated boost DC / DC converters that results in the lowest voltage is a bidirectional isolated boost DC / DC converter, at least one of the polyphase rectifier circuits connected to the isolated boost DC / DC converter connected to the position of the lowest voltage is a polyphase inverter, and the polyphase inverter converts DC power supplied via the bidirectional isolated boost DC / DC converter into polyphase AC power and supplies the converted AC power to the generator, thereby driving the generator.

5. The power generation device according to claim 1, wherein the plurality of polyphase rectifier circuits constitute a plurality of sets of polyphase rectifier circuit groups each including two or more polyphase rectifier circuits, each set of polyphase rectifier circuit groups has one composite DC output terminal formed by interconnecting the DC output terminals of the plurality of polyphase rectifier circuits included in that set of polyphase rectifier circuit groups, and the converter input terminal of each isolated step-up DC / DC converter is connected to the composite DC output terminal of a corresponding set of polyphase rectifier circuit groups among the plurality of sets of polyphase rectifier circuit groups.

6. The power generating device according to claim 5, wherein the plurality of polyphase ACs are a plurality of three-phase ACs, and the plurality of polyphase rectifier circuits are a plurality of three-phase rectifier circuits, and the generator comprises a stator having a plurality of stator coils arranged in a ring shape, and a rotor having a plurality of magnetic poles arranged in a ring shape facing the stator coil, and the plurality of stator coils form a plurality of three-phase coils, and the plurality of three-phase coils form a plurality of three-phase coil pairs each consisting of two three-phase coils of the same phase, and form a plurality of sets of three-phase coil groups each including a plurality of three-phase coil pairs, and the plurality of three-phase coil pairs included in each set of three-phase coil groups are respectively connected to a plurality of three-phase rectifier circuits included in one set of three-phase rectifier circuit groups out of the plurality of sets of three-phase rectifier circuit groups, and the plurality of magnetic poles are arranged so that the plurality of three-phase coil pairs included in each set of three-phase coil groups output three-phase ACs that are out of phase with each other.

7. The power generating device according to claim 6, wherein the stator coils are formed by concentrated winding, the number of the magnetic poles and the stator coils is poles:stator coils=2N((6n±1):6n) (where N is a natural number equal to or greater than 2, and n is a power of 2 including 1), the number of the plurality of isolated step-up DC / DC converters and the number of the plurality of three-phase coil groups is N, and the number of three-phase coil pairs included in each three-phase coil group is 2n.

8. The power generation device according to claim 1, wherein the voltage generated between the generator and the converter input terminals of each isolated step-up DC / DC converter is 400 V or less, and the voltage generated at the converter output terminals of each isolated step-up DC / DC converter is 1.2 kV or more.

9. The power generating device according to claim 1, comprising: a shaft base connected to the generator; and a rotary wind turbine fixed to the shaft base, wherein the generator generates electricity by rotating the shaft base using wind force received by the rotary wind turbine.

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