JP3847740B2 - Power generator - Google Patents

Description

  The present invention relates to an AC power generation device, and more particularly to a power generation device that is downsized to obtain an output with a constant frequency regardless of the magnitude of the rotational driving force.

  For example, as a principle of hydroelectric power generation or thermal power generation, the rotational driving force of a water turbine or a turbine is transmitted to an AC generator, power is generated based on the rotation of the rotor of the AC generator, and AC power is output. In this case, in order to obtain AC power as the generator output, it must be a constant frequency, adjusted to a voltage that does not exceed the rating, and the current and power according to the power used and the transmission capacity of the transmission line. Various adjustment controls such as phase adjustment are required. For this purpose, for example, various mechanical adjustments and controls such as adjustment control of gas and water amount, that is, adjustment control by a governor, angle adjustment of a blade of a prime mover, etc. to adjust the rotational force of a turbine or turbine as a generator input. I need it.

  On the other hand, as a recent trend, small output power generators such as small hydroelectric power generation and wind power generation (wind power generation has recently appeared with high output) are also commercialized, so-called under natural environment. This is in line with the trend of converting clean energy into electric power. Even with these small output power generators, devices and equipment such as governors are required, which makes maintenance and inspection cumbersome. Furthermore, regarding the installation of these power generators, wind power for obtaining rotational driving force is required. There is also a need to strictly select an installation location where energy can be obtained efficiently by considering the installation environment in advance or equivalent to or more than the above-mentioned thermal power generation so as to minimize the influence of such intensity changes.

  In addition, it is necessary to connect to the grid except for the generator that is for single operation. In the case of this grid connection, it is necessary to synchronize the generator output with the commercial power frequency. Is converted to direct current, an alternating current synchronized with a commercial alternating current power source is created by an inverter, and this alternating current is connected to the system.

JP 2002-315396 A

  Regardless of whether it is in a large-scale power generation plant or a small-output power generation device as described above, the generator body can be used to reduce equipment costs, simplify equipment, reduce maintenance and inspections by personnel, etc. There is a request to streamline the power generation equipment by simplifying by combining as many as possible devices and facilities such as detectors, adjustment devices, control devices, protection devices, etc. other than an AC generator as much as possible. is there. Meeting this demand for slimming leads to downsizing of the equipment. Depending on the season and season, for example, it can be easily installed and stored in a season with a lot of water or during a windy period. This will lead to the provision of a power generation device that makes it possible.

  Moreover, in wind power generation, etc., the installation location is strictly selected so that a steady input can be obtained as much as possible. Even if there is a large change in the rotational driving force, the influence of the change is reduced and is constantly There is a demand to obtain a power generation device that can generate power generation.

  Furthermore, it is a special case in a power generator for single operation used in ships, mountain huts, etc., but it is necessary to synchronize when connecting to other power generators and power transmission and distribution facilities. For this reason, conventionally, an inverter is separately required and expensive, and there is a problem that the efficiency is reduced due to the AC-DC or DC-AC conversion effect associated with the use of the inverter. In addition, when performing grid connection, high-speed circuit breakers are used to prevent isolated operation for system disconnection and to protect against load short-circuits in order to prevent dangers associated with live operation due to operation of the inverter even in the event of a load power failure due to disconnection. Therefore, it is necessary to make the connection protection device expensive and complicated.

  Furthermore, in wind power generation, there is also a demand to use wind energy as much as possible for power generation without separating the rotational driving force from the power generation device during strong winds.

  The present invention has been made in view of the above-mentioned problems, and it is possible to reduce the number of facilities and devices such as an adjustment control device or maintenance / inspection work as much as possible to make a slim power generator, regardless of the magnitude of the rotational driving force that is an input. When power generation is possible and grid connection is used, the number of converters such as inverters, isolated operation prevention measures and connection protection devices required for conventional grid connection are minimized, and rotational energy is used as effectively as possible. An object of the present invention is to obtain such a power generation device.

In order to solve the above-described problems and achieve the object, a power generation device according to the present invention includes a stator , a stator winding wound around the stator and to which an AC power supply is to be applied, a rotor, A rotor winding wound around a rotor and to which a voltage switched from a DC power source is to be applied, a commutator connected to the rotor winding, an electric motor that rotates in synchronization with the AC power supply, and the electric motor A brush that rotates in synchronization with the rotation of the power supply, and supplies power to the rotor winding through the brush that rotates in synchronization with the frequency of the AC power source and the commutator. A rotating magnetic field is generated in the rotor, and a power generation output synchronized with the AC power supply is obtained from the stator winding .

According to the present invention, a rotating magnetic field can be generated in the rotor by supplying power to the rotor winding through the brush that rotates in synchronization with the frequency of the AC power source and the commutator. An electromotive force due to a change in magnetic flux is induced in the winding, and power generation becomes possible. Further, since the stator winding is connected to an AC power source and is AC-excited, system interconnection is possible.

The power generator according to the next invention is characterized in that, in the above invention, the voltage applied to the brush is fed from the DC power supply via a slip ring that rotates with the rotation of the electric motor .

According to the present invention, since the voltage applied to the brush is fed from the DC power source via the slip ring that rotates with the rotation of the electric motor, the DC power source needs to be integrated with the rotating shaft. Absent.

According to the present invention, a stator , a stator winding wound around the stator and to which an AC power source is to be applied, a rotor, and a rotation around which the voltage wound around the rotor and switched from the DC power source is to be applied. And a brush that rotates in synchronism with the rotation of the motor, and includes a commutator connected to the rotor winding, a commutator connected to the rotor winding, and a brush that rotates in synchronization with the rotation of the motor. Since the rotor winding is fed via a brush that rotates in synchronization with the rotor and the commutator, it is possible to obtain a power generation output synchronized with the AC power source from the stator winding. Play.

According to the next invention, the voltage applied to the brush, so it was decided to be powered from a DC power source via a slip ring which rotates with the rotation of the motor, without an integral structure equipped with a DC power source to the rotary shaft There exists an effect that a power generator can be constituted .

  Exemplary embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

[First Embodiment]
FIG. 1 is a simplified configuration diagram of a power generator according to a first embodiment of the present invention. Although this power generation device can function as a single-operation power generation device or a grid-connected power generation device, this embodiment shows a configuration in the case of functioning as a single-operation power generation device. In the configuration diagram shown in the figure, some modifications are made or a schematic configuration is shown for easy understanding of the configuration of the power generation device. For example, in an actual power generation apparatus, the rotor 6 is configured to be inserted into the magnetic pole piece 22, but in the same figure, in order to clarify the schematic structure of the rotor 6, it does not overlap with the magnetic pole piece 22. Is displayed.

In FIG. 1, a rotor 6 having a rotor core 5 around which a rotor winding 4 is wound with respect to a stator 3 having a stator core 2 around which a field winding (stator winding) 1 is wound. Is rotatably arranged with a wind turbine 7 as a prime mover as a drive source. A commutator 8 having a plurality of commutator pieces 81 connected to the rotor winding 4 is rotatably attached to the rotor 6.

  The end of the yoke 21 of the stator core 2 around which the field winding 1 is wound constitutes a two-pole field pole having a pole piece 22. In this case, the field pole can have not only a two-pole configuration but also a multiple of two. The field winding 1 can also be connected to a three-phase AC power supply, but it can also be configured with three poles or a multiple of 3 poles as field poles. Note that the shape of the stator core 2 in FIG. 1 is not an actual shape, and is shown as forming the end of the yoke 21 of the stator core 2 for convenience of explanation. Further, the pole piece (field pole) 22 has a shape matching the rotor 6, and the yoke 21 is simply illustrated as a structure in which the field winding 1 is wound by connecting the pole piece 22.

  The rotor 6 has a rotor winding 4 composed of a plurality of die-wound coils in which coil sides 41 are inserted into slots formed so as to be arranged in the circumferential direction of the outer periphery thereof and linearly formed in the axial direction. ing. Winding ends (electrical input / output terminals) of the respective coiled coils are individually connected to the commutator piece 81. As described above, the structures of the stator 3 and the rotor 6 are so-called AC commutator machines.

  On the other hand, a synchronous motor 9 connected to a commercial AC power source is provided separately from the generator having the structure of the AC commutator. The rotating shaft 17 of the synchronous motor 9 is provided with a brush holder that supports the brush 12 that contacts the two slip rings 10 and 11 and the commutator piece 81 of the commutator 8 with a desired contact resistance value. The included support member 13 is integrally connected. Therefore, the slip rings 10 and 11 and the support member 13 rotate integrally with the rotary shaft 17. In this case, the brushes 12 that make contact with the commutator piece 81 of the commutator 8 in a pair are electrically connected to the slip rings 10 and 11, respectively. These slip rings 10 and 11 are connected to a DC power source 14 that can be charged via a brush 12. In FIG. 1, the brush 12 which is two brushes of a single phase is illustrated, but the number of brushes varies depending on the number of phases or the number of poles. Regardless of the embodiment, the DC power supply 14 can be any DC power supply other than the secondary battery.

  Thus, the brush 12 is synchronously rotated in the circumferential direction of the commutator 8 by driving the synchronous motor 9 while being in contact with the commutator 8. That is, FIG. 1 has a so-called AC commutator structure as a generator, but the brush 12 maintains the positional relationship between the paired brushes, and is connected to the commutator piece 81. Thus, the commutator 8 is synchronously rotated in the circumferential direction (hereinafter simply referred to as the circumferential direction) while maintaining a desired contact resistance value. The synchronous rotation state of the brush 12 is always maintained regardless of whether the rotor 6 and thus the commutator 8 are stopped due to the rotational drive force from the wind turbine and are rotating due to the rotational drive force.

  In FIG. 1, slip rings 10 and 11 attached to the rotating shaft 17 of the synchronous motor 9 are necessary for connecting the DC power source 14 placed in the installed state to the brush 12 which is a rotating part. When the power supply 14 is configured to rotate integrally with the rotating shaft mounted thereon, the slip rings 10 and 11 and the brush that contacts the slip rings 10 and 11 are not required.

  FIG. 2 is a diagram for explaining a change in the direction of the current flowing through the rotor winding 4, and the rotor winding 4 composed of 12 unit windings (form winding coil) is connected to the rotor winding 4. The state which expand | deployed the alternating current commutator machine which has the commutator 8 made into a plane is shown. Here, the structure of the rotor winding provided in a general AC commutator is the same in basic terms as the structure of the rotor winding 4 provided in the power generator of the present invention. The above-described change in the current direction will be described by taking a commutator as an example.

  In FIG. 2, when the brush 12 contacts the commutator piece 81 of the commutator 8, a closed circuit is formed between the DC power supply 14 and the rotor winding 4. At this time, the current from the DC power supply 14 is shunted in the right and left directions in the rotor winding 4 from the left position to the right position in the drawing. Next, when the brush 12 is brought into contact with the next brush movement position, for example, the ho and ho positions of the commutator piece 81 by the rotation of the brush 12, the brush 12 rotates from the position of the left ho to the position of the right ho. The child winding 4 is shunted in two directions, right and left.

  Thus, by rotating the brush 12 in synchronization with the commercial power supply frequency, the contact position of the brush 12 is sequentially shifted, and the current from the DC power supply 14 flowing in the rotor winding 4 is sequentially supplied to the adjacent unit winding. Will change. This means that the electromagnet M indicated by the broken line in the figure generated by the current flowing from the DC power supply 14 into the rotor winding 4 generates a rotating magnetic field that rotates in synchronization with the commercial power supply frequency due to the change in current. . That is, the forward movement of the brush 12 on the commutator piece 81 causes conduction switching between the brush 12 and the commutator piece 81 (to constitute a contact switching means), and the current from the DC power source 14 is supplied to the rotor winding 4. A rotating magnetic field is generated in the rotor 6 by the transition current at.

  FIG. 3 is a diagram for explaining a change in the magnetic field generated in the field winding by the rotating magnetic field of the rotor. In the rotor 6, the current flowing from the DC power source 14 through the slip ring 11 (not shown) and the brush 12a (shown by black circles in the figure) flows through the rotor winding 4, and the brush 12b (shown by white circles in the figure), The slip ring 10 (not shown) is returned to the DC power supply 14. Due to the current flowing through the rotor winding 4, a rotating magnetic field as shown in FIG. This rotating magnetic field causes a change in the magnetic field at the pole piece 22 and generates an induced electromotive force in the field winding 1.

  In FIG. 3, the change in the strength of the magnetic field generated in the field winding 1 is indicated by the size of letters N and S in the figure. This change in the magnetic field is caused by a change in the amount of magnetic flux linked to the field winding. In the state 1, the S pole having the opposite polarity to the N pole of the rotating magnetic field is generated in the left pole piece of the figure, and the N pole having the opposite polarity to the S pole of the rotating magnetic field is generated in the right pole piece of the figure. On the other hand, in the state of 5, the N pole having the opposite polarity to the S pole of the rotating magnetic field is generated in the left pole piece of the figure, and the S pole having the opposite polarity to the N pole of the rotating magnetic field is generated in the right pole piece of the figure. Arise. Thus, the strength of the magnetic field generated in the field winding by the rotation of the rotating magnetic field changes as 1 to 5. On the other hand, the electromotive force generated in the field winding is proportional to the change in the magnetic flux, that is, the change in the magnetic field, and as shown in FIG. It becomes.

  In the description so far, the wind turbine 7 is in a stopped state without particular notice, and the rotor 6 has been treated as not physically rotating. Then, next, the case where the rotor 6 is physically rotating by rotation of the windmill 7 is demonstrated.

  First, consider the period of the rotating magnetic field. The change in the rotating magnetic field is caused by rotating the brush 12 as described above. That is, as shown in FIG. 3, the rotating magnetic field is changed by forming a half-period rotating magnetic field between 1 and 5, and this period is the same as the period of the electromotive force induced in the field winding 1. is there. That is, the period of the rotating magnetic field is the same as the rotation period of the brush 12 and does not depend on the rotation speed of the rotor 6. Thus, in FIG. 1, the frequency of the AC output output from the field winding 1 can be controlled by the synchronous motor 9 without depending on the rotational speed of the rotor 6. For example, when the synchronous motor 9 rotates in synchronization with the frequency of the commercial power supply, an AC output having the same frequency as that of the commercial power supply can be taken out.

  Next, the magnitude of the electromotive force generated in the field winding 1 will be considered. The fact that the magnitude of the electromotive force generated in the field winding 1 is proportional to the amount of change in the magnetic flux interlinking the field winding 1 is as described above. That is, the magnitude of the electromotive force generated in the field winding 1 is proportional to the amount of magnetic flux interlinking the field winding 1 per unit time. On the other hand, as the wind turbine 7 physically rotates and the rotation speed increases, the number of unit windings of the rotor winding 4 crossing the field winding 1 increases. This is because the amount of magnetic flux passing through the field winding 1 per unit time increases, and therefore, when the rotational speed of the rotor 6 increases, the electromotive force generated in the field winding 1 increases. FIG. 4 shows this relationship.

  FIG. 4 is a diagram showing the relationship between the rotational speed of the rotor 6 and the electromotive force (voltage) generated in the field winding 1 in the power generator according to the first embodiment. The two curves shown in the figure show electromotive forces generated by different actions, one being an electromotive force (T) due to a transformer coupling action, and the other being an electromotive force (R) due to rotation. The definition (meaning) of these two electromotive forces will be described later.

Next, in the power generation apparatus of this embodiment shown in FIG. 1, the operation when the movement of the windmill 7 is taken into account will be described with reference to FIG. 1 or FIG.
In particular,
1 When the rotor 6 is stopped Also, by the rotational driving force generated by the rotation of the windmill 7,
2 When the rotor 6 is rotating at a speed lower than the synchronization speed 3 When rotating at the synchronization speed 4 When rotating at a speed exceeding the synchronization speed,
A description will be given of a voltage generated in the field winding 1 over each of the states.

(When rotor 6 is stopped)
In FIG. 1, when the brush 12 rotates at the synchronous speed, switching of the direct current flowing from the direct current power source 14 occurs in the rotor winding 4 due to the movement of the brush 12. Further, due to the switching of the direct current, a synchronous rotating magnetic field is generated in the rotor 6, and an induced electromotive force is generated in the field winding 1 by the rotating magnetic field in synchronization with the switching of the direct current. Here, the electromotive force generated in the field winding 1 is generated based on the magnetic coupling between the field winding 1 and the rotor winding 4, and the magnitude of the electromotive force generated at this time is This electromotive force is referred to as an electromotive force due to a transformer coupling action.

  As shown in FIG. 4, an electromotive force is generated by the transformer coupling action when the wind turbine 7 is stopped. In this way, even when the wind turbine 7 is stopped and there is no rotational driving force and the rotor 6 is stopped, the field winding 1 receives a magnetic flux change at the field pole, so that an induced electromotive force is generated.

(When the rotor 6 is rotating at a speed less than the synchronous speed)
Regarding the induced electromotive force generated in the field winding 1, when the wind turbine 7 starts rotating from a stopped state and the rotor 6 rotates at a speed lower than the synchronous speed, the following occurs. As the rotor 6 begins to rotate due to the rotational driving force of the windmill 7 and the physical rotation increases, the speed difference between the rotation of the rotor 6 and the synchronous rotation of the rotating magnetic field gradually decreases.

  That is, as compared with when the rotor 6 is stopped, the rotational speed of the rotor 6 approaches the synchronous speed, and the electromotive force generated only by the transformer coupling action generated when the rotor 6 is stopped. On the other hand, it decreases with the rotation of the rotor 6, while the rotor 6 has windings that are DC-excited by the switching operation accompanying the rotation of the brush 12. The electromotive force to be increased gradually. This electromotive force is referred to as “electromotive force due to rotation” in order to distinguish from the above “electromotive force due to transformer coupling action”.

  As shown in FIG. 6, when the rotor 6 rotates at a speed lower than the synchronous speed, the electromotive force (T) due to the transformer coupling action that is not based on the physical rotation of the rotor 6 is generated as the whole power generation apparatus. On the other hand, the electromotive force (R) due to the rotation generated based on the rotation of the rotor 6 increases. As the rotational speed of the rotor 6 increases, the conduction switching speed depending on the rotation of the brush 12 becomes relatively slow, the reactance of the rotor winding 4 decreases, and the impedance of the rotor winding 4 decreases. . As a result, the current that generates the rotating magnetic field increases, the magnetic field becomes stronger, and the induced electromotive force in the field winding 1 also increases.

(When the rotor 6 is rotating at the synchronous speed)
When the rotation driving force of the windmill 7 causes the rotation of the rotor 6 and the rotating magnetic field due to conduction switching accompanying the rotation of the brush 12 to have the same synchronous speed, the input / output of the rotor winding 4 selected by chance. An electromotive force is generated in the field winding 1 by the synchronous rotation of the electromagnet (not depending on the switching of the rotor winding 4) generated by the DC magnetic field based on the DC current from the DC power supply 14 when only the terminals are conducted. Since this electromotive force is generated by the magnetic flux traversing the field winding 1, only the electromotive force due to the rotation described above is generated, and only the DC power source flows through the rotor winding 4. It disappears and the electromotive force due to this action becomes substantially zero (see FIG. 4).

(When the rotor 6 rotates exceeding the synchronous speed)
When the rotation of the rotor 6 is rotated at a speed exceeding the synchronous speed (referred to as “over sync speed”) due to the high-speed rotation of the windmill 7, the rotor 6 is synchronously rotated and the electromagnet of the rotor winding 4 is synchronously rotated. Will rotate even faster. That is, the rotating magnetic field due to the current flowing in the field winding 1 and the rotor winding 4 rotates with a delay from the rotation of the rotor 6. Therefore, the rotor 6 itself is physically rotating even at the moment when the brush 12 that is the source of the magnetic flux change of the field winding 1 and the rotation of the rotating magnetic field does not rotate. As a result, the electromotive force generated by the rotation of the field winding 1 due to the synchronous rotation of the electromagnet of the rotor winding 4 is further increased based on the magnetic flux change caused by the rotation of the rotor 6 by the amount exceeding the synchronous speed. Electric power is applied to the field winding 1. Further, the voltage generated in the field winding 1 due to the transformer coupling action is generated again when the rotation of the rotor 6 exceeds the synchronous speed, causing the current of the rotor winding 4 to be switched. Note that this voltage is in phase with the case where the speed is lower than the synchronous speed, and increases as the rotation of the rotor 6 increases (see FIG. 4).

To summarize the operation (action) described above, the voltage generated in the field winding 1 is as follows.
1 When the rotor 6 is stopped, only an electromotive force is generated by the transformer coupling action,
2 When the rotor 6 rotates at a speed less than the synchronous speed, the electromotive force due to the transformer coupling action decreases, but the electromotive force due to the rotation increases,
3 When the rotor 6 is rotating at the synchronous speed, only the electromotive force due to the rotation is generated, and the electromotive force due to the transformer coupling action is substantially zero,
4 When the rotor 6 rotates exceeding the synchronization speed, the electromotive force due to the rotation increases, and the electromotive force due to the transformer coupling action rises again at the boundary of the synchronization speed.

  Thus, the power generation output of the synchronous frequency synchronized with the period of the rotating magnetic field generated by the rotor winding 4 rotating at the synchronous speed over the entire region where the rotor 6 rotates from the stopped state beyond the synchronous speed. Can be obtained. As shown in FIG. 4, in the region where the rotor 6 is rotating at a speed lower than the synchronous speed, it exhibits a behavior as a synchronous generator, and in the region where the rotor 6 is rotated above the synchronous speed, It will behave as an induction generator.

  Note that when the rotational speed of the rotor 6 increases, the current flowing through the rotor winding 4 increases, but the reactance of the rotor winding 4 increases and the current flowing through the rotor winding 4 is limited. Therefore, as shown in FIG. 4, the electromotive force due to the rotation gradually becomes saturated. On the other hand, if the current flowing through the rotor winding 4 is reduced, the electromotive force of the field winding 1 can be suppressed. That is, by actively controlling the rotor current that increases as the rotational speed of the rotor 6 increases, a desired level of AC output can be obtained in accordance with fluctuations in the rotational speed.

  As described above, according to the power generation apparatus of this embodiment, the rotor including the rotor winding and the stator including the stator winding are provided, and the rotor winding is energized at a predetermined cycle. Since it is excited by a DC power source via the contact switching means, an AC output proportional to the rotational speed of the rotor can be taken out.

[Second Embodiment]
FIG. 5 is a simplified configuration diagram of a power generator according to a second embodiment of the present invention. This embodiment shows a configuration in the case of functioning as a grid-linked power generation device. The power generator shown in the figure is configured such that the field winding 1 of the power generator shown in FIG. 1 is connected to a commercial power source, and the power generation output of the power generator is output to the commercial power source (system) side so that the system can be linked. ing. In addition, about another structure, it is the same as that of 1st Embodiment shown in FIG. 1, or is equivalent, The same code | symbol is attached | subjected and shown about these components.

  Next, the operation of the power generator of this embodiment shown in FIG. 5 will be described. FIG. 6A is a diagram illustrating a relationship between the rotational speed of the rotor 6 and the electromotive force (voltage) generated in the rotor winding 4 in the power generation apparatus according to the second embodiment. These are figures which show the relationship between the rotational speed of the rotor 6 and the electromotive force (voltage) which arises in the field winding 1 in the electric power generating apparatus of 2nd Embodiment.

  In FIG. 5, as described in the first embodiment, when the brush 12 rotates at the synchronous speed, switching of the direct current flowing from the direct current power source 14 is performed on the rotor winding 4 by the movement of the brush 12. Arise. In addition, the synchronous rotating magnetic field generated by the switching of the direct current generates an electromotive force due to the transformer coupling action defined above. Note that this electromotive force is generated even when the rotor 6 is stopped, as in the case of the first embodiment.

  On the other hand, in the power generator of this embodiment, unlike the power generator of the first embodiment, an AC electromotive force voltage is generated in the rotor winding 4 due to a change in magnetic flux due to the field current of the field winding 1. Is. The terminal voltage of the DC power source 14 is applied between the two commutator pieces selected by the rotation of the brush 12. At this time, the electromotive force induced by the field magnetic flux and the voltage applied by the DC power source 14 are applied to the rotor winding 4 in opposite directions. The event of being applied in the reverse direction is a case where the speed is lower than the synchronization speed, which will be described later. Therefore, in order to generate a rotating magnetic field in the rotor winding 4, the terminal voltage by the DC power supply 14 is set higher than the induced electromotive force voltage determined by the turn ratio between the field winding 1 and the rotor winding 4. It is necessary to.

  That is, when attention is paid to the voltage generated in the rotor winding, when the voltage generated in the rotor winding is E2 and the DC power supply voltage is E1, there is a rotational speed P1 of the rotor 6 where E1 = E2. And the area | region where the rotational speed of the rotor 6 exceeds this P1 turns into an electric power generation area | region (refer FIG. 6-1). On the other hand, in terms of the voltage generated in the field winding, the electromotive force (R) due to rotation starts from the point P1 and increases linearly, and the electromotive force (T) due to the transformer coupling action is As in the case of the first embodiment, starting from a predetermined voltage determined by the turn ratio between the field winding 1 and the rotor winding 4, the rotation of the rotor 6 is reduced synchronously. And then rises again after exceeding the synchronization speed (see FIG. 6-2).

  As is clear from the above, in the power generation device of this embodiment, the period of the rotating magnetic field rotating at the synchronous speed over the entire region in which the rotor 6 rotates beyond the synchronous speed from the point P1. It is possible to obtain a power generation output having a synchronized frequency. As shown in FIGS. 6A and 6B, in a region where the rotational speed of the rotor 6 is less than the synchronous speed from P1, the rotor 6 behaves as a synchronous generator, and the rotor 6 rotates beyond the synchronous speed. In this area, it will behave as an induction generator.

  On the other hand, the operation in a region other than the above region, that is, in a region where the rotational speed of the rotor 6 is P1 or less is as follows. That is, in this region, as shown in FIG. 6A, an applied voltage (E1) applied to the rotor winding 4 by the DC power source 14 is an electromotive force (E2) generated in the rotor winding 4 by the field winding 1. ) And current flows into the DC power supply 14 side. Therefore, in this region, the behavior as an induction motor is exhibited. At this time, the rotation start of the blade near the cut-in wind speed can be supported (see FIG. 6-2).

  Moreover, if the voltage (E1) of the DC power supply 14 is set to be equal to or slightly higher than the electromotive force (E2) generated in the rotor winding 4 by the field winding 1, the voltage of the DC power supply 14 is lowered. Even so, after the voltage of the DC power supply 14 is restored by the charging current, it does not behave as an induction motor, so that the state where the power generation device does not become a system load can be maintained.

FIG. 7 is an explanatory diagram showing the characteristics of the power generation device of the second embodiment from the viewpoint of the DC power supply 14 on a graph of the voltage generated in the rotor winding 4 shown in FIG. 6A. Hereinafter, the characteristics of this power generator will be described with reference to FIG. As shown in the figure, three regions based on the rotational speed of the rotor 6, that is,
1 A region from the stop state to the rotational speed P1 2 A region from the rotational speed P1 to the synchronous speed 3 A region beyond the synchronous speed Each region will be described.

(Area from stop state to rotation speed P1)
In this region, as described above, a current flows into the DC power supply 14 side. Moreover, since this electric current flows in the direction which charges DC power supply 14, if a DC power supply is a secondary battery, it can charge. Further, as described above, this region is also a region that exhibits the behavior as an induction motor, and is a region that can support the rotation start of the blades of the windmill 7.

(Area that exceeds the rotational speed P1 and reaches the synchronous speed)
This region is a region where power can be generated by the DC power supply 14. As shown in FIG. 7, since the rotor winding 4 is excited based on the difference voltage ΔV1 between the DC power supply voltage (E1) and the voltage (E2) generated in the rotor winding 4, the rotation speed is increased. Along with this, the generated voltage increases.

(Area exceeding the synchronization speed)
In the region above the synchronous speed, the polarity of the current flowing through the rotor winding 4 is reversed as shown in FIG. Therefore, in this region, the rotor winding 4 is excited based on the difference voltage ΔV3 between the DC power supply voltage (E1) and the voltage (E2) generated in the rotor winding 4, and a larger generated voltage Can be understood. Note that ΔV2 indicates a difference voltage when the DC power supply voltage is set to 0 V, and indicates that power generation is possible even when there is no DC power supply voltage.

  In addition, from the above-described contents, this region shows that the secondary battery can be charged while enabling power generation by reversing the polarity of the DC power source that is the secondary battery.

  Next, an experimental example using a prototype is described. FIG. 8 is a diagram showing a configuration of a prototype manufactured actually. In the figure, the same reference numerals are given to the same parts as those shown in FIG. In FIG. 8, a transformer 19 that steps down the voltage of the commercial AC power supply 18 is provided, and a field circuit is formed by the field winding 1 of the generator using the output of the transformer 19 as an AC power supply. Although not shown in FIG. 8, the commercial AC power source 18 is also a power source that synchronously rotates the brush 12 via the synchronous motor 9. The rotor 6 is configured to be manually rotated through the speed increaser 23, for example. Further, a DC power source 14 is connected to the commutator 8 and the brush 12 which are connected to the lead wire of the rotor winding (not shown). In FIG. 8, a measuring instrument (for example, an oscilloscope 24) for measuring a field current and a field voltage (system voltage) is provided.

  FIG. 8 shows the rotation mechanism of the brush 12 and the power supply from the DC power source 14 to the brush 12 in a simplified manner. FIG. 9 shows an example in which the wind turbine 7 is connected as a prime mover. It is the block diagram which illustrated the connection of these and the rotation mechanism of the brush 12 more concretely. In FIG. 9, the windmill 7 and the speed increaser 23 which are the prime movers are connected to the rotating shafts of the rotor 6 and the commutator 8. The brush 12 in contact with the commutator 8 is attached and fixed to a support member 13 including a brush holder. The support member 13 has teeth that mesh with the gear 25 on the outer periphery. Further, a slip ring (not shown in FIG. 9) is formed on the support member 13 corresponding to the brush 12, and this slip ring is connected to the DC power source 14. With such a structure, the brush 12 connected to the DC power source 14 via the slip ring rotates at a synchronous speed based on the driving of the synchronous motor 9.

  FIG. 10 is a diagram illustrating an example of a circuit configuration of the DC power supply 14. A DC power source 14 shown in FIG. 1 has both functions of a voltage source and a current source, a switch 111 for outputting the output of the battery 110 as a secondary battery as a voltage source, and a current when the switch 111 is opened. A resistor 112, a transistor 113, a Zener diode 114, and a bias resistor 115 for functioning as a source are provided. In the figure, when the switch 111 is turned on, the voltage of the battery 110 is directly applied to the slip rings 10 and 11 (not shown) to function as a voltage source. On the other hand, when the switch 111 is opened, the current of the resistor 112 is adjusted to a reverse bias by the Zener diode 114, so that the energization current of the transistor 113 is controlled to be constant and can function as a current source.

  FIGS. 11 to 13 are graphs showing voltage and current waveforms by the oscilloscope 24, that is, field voltage and field current waveforms in the circuit shown in FIG. FIG. 11 shows that the circuit switch 26 of the synchronous motor 9 connected to the AC commercial power supply is opened without flowing the rotor winding current without opening the circuit switch 26 of the DC power supply 14 in FIG. The voltage V and current I of the field winding 1 shown in FIG. 5 in the state are shown, and the current I is delayed by the inductance of the field winding 1 with respect to the voltage V. An induced electromotive force is generated in the rotor winding 4 based on an alternating magnetic field or a rotating magnetic field generated by the current I.

  12, the circuit switches 26 and 27 of FIG. 9 are turned on, the synchronous motor 9 is driven to rotate the brush 12 at the synchronous speed, and the DC power source (voltage source) 14 is rotated through the slip ring and the brush 12 to the rotor. A state in which a voltage is applied to the winding 4 is shown. In this case, 20V was used as the terminal voltage of the DC power supply 14, and 8V was used as the secondary voltage V of the transformer 19. In this state, the induced electromotive force generated in the rotor winding 4 depending on the number of rotor windings based on the change in magnetic flux due to the current I of the field winding 1 is lower than the DC power supply voltage, and thus the brush 12 and the rectifier are rectified. Due to the movement of the contact position with the child piece 81, a rotating magnetic field is generated in the rotor winding 4, and this rotating magnetic field changes the field magnetic flux generated by the field winding 1 and generates an electromotive force in the field winding 1. As a result, as shown in FIG. 12, a field current I having an approximately opposite phase to the field voltage V flows, and power is sent from the generator to the system side. That is, the rotating magnetic field formed by the exciting current from the DC power source 14 changes the magnetic flux of the field winding 1, thereby inducing an electromotive force in the field winding 1. At this time, the field current I has a phase opposite to that of the field voltage V, and the excitation current from the DC power source 14 is 15 mA, and the excitation current is very small.

  FIG. 13 is a graph showing a waveform obtained by rotating the rotor 6 through the gearbox 23 by a prime mover (for example, manually) in the circuit state of the waveform shown in FIG. Here, as shown in the figure, the waveform of the field current I does not change in phase even when compared with the waveform of FIG. 10, and the peak value increases with the rotation of the prime mover. That is, the output energy of the prime mover is converted into a generated current, and a field current I having a large amplitude is obtained. The frequency and phase of the field current are constant regardless of the rotational speed of the rotor 6.

  As described above, the power generation apparatus according to this embodiment has an advantage that the generated power is constantly obtained even when there is a wide range of changes in the rotational driving force, and no equipment such as an inverter is required when performing grid interconnection. Have. In addition, it is easy to obtain an output with a constant frequency. On the other hand, by using the DC power supply device as the current source and the voltage source described above, an adjustment device for adjusting the frequency, etc. Therefore, it is possible to simplify the control device, the protection device, and the like, and to reduce the equipment cost and maintenance inspection.

  As shown in FIG. 5, each commutator piece 81 is configured to be connected to each unit winding, but a current is passed through the rotor winding 4 to form a rotating magnetic field on the rotor 6. In view of the feature of the present invention, for example, if a plurality of unit windings are collectively connected to a single commutator piece 81, the number of commutator pieces can be reduced.

It is a simplified lineblock diagram of the power generator concerning a 1st embodiment of this invention. FIG. 6 is a diagram for explaining a change in the direction of current flowing through the rotor winding 4. It is a figure for demonstrating the change of the magnetic field produced in a field winding by the rotating magnetic field of a rotor. It is a figure which shows the relationship between the rotational speed of the rotor 6, and the electromotive force (voltage) which arises in the field winding 1 in the electric power generating apparatus of 1st Embodiment. It is a simplified block diagram of the electric power generating apparatus concerning 2nd Embodiment of this invention. It is a figure which shows the relationship between the rotational speed of the rotor 6, and the electromotive force (voltage) which arises in the rotor coil | winding 4 in the electric power generating apparatus of 2nd Embodiment. It is a figure which shows the relationship between the rotational speed of the rotor 6, and the electromotive force (voltage) which arises in the field winding 1 in the electric power generating apparatus of 2nd Embodiment. It is explanatory drawing which showed on the graph of the voltage which generate | occur | produces in the rotor coil | winding 4 shown to FIGS. 6-1 with the characteristic of the electric power generating apparatus of 2nd Embodiment which made the direct-current power supply 14 a viewpoint. It is a figure which shows the structure of the prototype manufactured actually. It is the figure which illustrated the connection of direct-current power supply 14, and the rotation mechanism of brush 12 more concretely. 2 is a diagram illustrating an example of a circuit configuration of a DC power supply 14. FIG. It is a figure which shows the waveform (DC power supply disconnection, synchronous motor non-drive) of the field voltage V and the field current I when there is no rotational driving force. It is a figure which shows the waveform (DC power supply connection, synchronous motor drive) of the field voltage V and the field current I when there is no rotational driving force. It is a figure which shows the waveform (DC power supply connection, synchronous motor drive) of the field voltage V and field current I in case there exists rotational driving force.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Field winding 2 Stator iron core 3 Stator 4 Rotor coil 5 Rotor iron core 6 Rotor 7 Windmill 8 Commutator 9 Synchronous motor 10,11 Slip ring 12,12a, 12b Brush 13 Support member 14 DC power supply 16 Brush moving position 17 Rotating shaft 18 Commercial AC power supply 19 Transformer 21 Yoke 22 Magnetic pole piece 23 Speed increaser 24 Oscilloscope 25 Gear 26, 27 Circuit switch 41 Coil side 81 Commutator piece 110 Battery 111 Switch 112 Resistor 113 Transistor 114 Zener diode 115 Bias resistor

Claims (2)

A stator, a stator winding wound around the stator and to which an AC power supply is to be applied, a rotor, and a rotor winding wound around the rotor and to which a voltage switched from a DC power supply is to be applied; A commutator connected to the rotor winding, an electric motor that rotates synchronously with the AC power supply, and a brush that rotates synchronously with the rotation of the electric motor,
A rotating magnetic field is generated in the rotor by supplying power to the rotor winding via the brush that rotates in synchronization with the frequency of the AC power source and the commutator, and the stator winding power generation apparatus characterized by obtaining a power generation output in synchronization with the AC power source. The power generation apparatus according to claim 1 , wherein the voltage applied to the brush is fed from the DC power source through a slip ring that rotates with the rotation of the electric motor .

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