JP6444676B2 - Generator - Google Patents

Description

  The present invention relates to a permanent magnet-less generator used in automobiles, small wind power generators, small generators using running water, and the like.

There are induction generators and synchronous generators as generators that generate electricity by rotation. Induction generators do not require excitation in the rotor windings, but they must be linked to the system and rotated at a high rotational speed to make them compact. Not suitable for generators. Therefore, a synchronous generator is often used in a small wind power generator or the like.
However, since a normal synchronous generator uses a permanent magnet to generate a field, the rare metal, which is a component of the permanent magnet, is expensive and the entire generator is expensive. Torque increases. For this reason, it is not suitable for a generator that generates power with a slight natural force, such as a small wind power generator. There is a separately-excited synchronous generator that uses an electromagnet instead of a permanent magnet. However, a configuration for supplying power to the electromagnet from the outside is necessary, and the configuration is complicated by an external power source.

  There has been proposed a self-excited synchronous generator that solves these problems and does not require a permanent magnet and external power supply (Patent Document 1). This generator uses the residual magnetism of the iron core to increase the current that flows in the field winding by self-excitation, so that the magnetic flux required for power generation can be supplied with an expensive permanent magnet or an external power source for excitation. Produced without need.

JP 2006-149148 A

  In order to drive generators used in automobiles, such as electric brakes and auxiliary machines, attempts have been made to use generators as auxiliary power sources in addition to battery power. Such automobile generators, small wind generators installed in homes, small-scale facilities, small generators using running water, and the like are required to be small and light. The self-excited generator described above is more efficient than a separately-excited generator, but the output density (referred to as output per unit volume) is small, and there is a problem in improving the output density.

  An object of the present invention is to provide a generator having a high output density while being self-excited.

The generator of the present invention includes an output iron core in which an output winding is wound, and a field iron core in which a main field winding and a subfield winding are wound, and the output iron core and the field iron core In any of the self-excited generators in which either one becomes a stator and the other becomes a rotor and the generated power is obtained by relative rotation between the stator and the rotor,
A rectifier is connected in parallel to the main field winding, a rectifier is connected in series to the subfield winding, and a circuit in which the subfield winding and the rectifier are connected in series is the main field winding. Only the current in the same direction as the current flowing through the main field winding is connected to the field winding in parallel with the field winding.
Per cross-sectional area of a cross section perpendicular to the rotational center of the rotor, the cross-sectional area of the sub-field winding slot the sub field winding disposed on said field core is accommodated, provided in the field core It is in characterized in that not smaller than the cross-sectional area of the main field winding slot the main field winding is accommodated.
In addition, each field winding is accommodated in each field winding slot without a gap, and the cross-sectional area of the range in which this field winding is accommodated is defined as the cross-sectional area of each slot.
More preferably, the cross-sectional area of the subfield winding slot is 7 to 40% of the cross-sectional area of the main field winding slot.

  According to this configuration, since it is a self-excited type that performs excitation using the main field winding, power generation can be performed without the need for a permanent magnet or an external power source that supplies power for external excitation from the outside. Since no permanent magnet is used, no cogging torque is generated, and the rotor can be rotated with a small torque. Therefore, in the case of a small and light generator, power can be generated by a slight external force and can be used effectively.

  In this self-excited generator, if the cross-sectional area of the subfield winding slot is increased, the wire diameter can be increased and the electric resistance value of the subfield winding can be reduced. Becomes larger. Conversely, when the cross-sectional area of the subfield winding slot is reduced, the magnetic resistance is reduced, but the wire diameter of the subfield winding is reduced and the electric resistance value is increased. The strength of the field changes depending on the balance between the magnetic resistance value and the electric resistance value. The output generated depends on the strength of the field. Magnetic field analysis was performed to find the optimum ratio of the slot area of the main field winding and subfield winding that can increase the output. As a result, it was found that the output is increased by making the cross-sectional area of the subfield winding slot smaller than the cross-sectional area of the main field winding slot. That is, it was found that the power density was increased. It has also been found that the output is highest when the cross-sectional area of the subfield winding slot is 7 to 40% of the cross-sectional area of the main field winding slot.

In the present invention, initial excitation means for applying a magnetic force to one or both of the output iron core and the field iron core may be provided to the extent necessary for the initial excitation of power generation. The initial excitation means may be a magnetizing means or a permanent magnet.
When the initial excitation means is provided, power generation can be reliably started even if the residual magnetism is excessively reduced after low-speed rotation or after low-speed rotation after long-term rotation stoppage or after disassembly and maintenance. In the self-excited generator, the magnetic flux increases as it rotates, so that the magnetic force required for the initial excitation is very small. For this reason, even if the initial excitation means is a magnetizing means or a permanent magnet, a slight one is sufficient. The term “magnetization” refers to magnetization so that residual magnetism is generated after the end of the magnetization process. A simple configuration is required for the magnetizing means.

The generator of the present invention includes an output iron core in which an output winding is wound, and a field iron core in which a main field winding and a subfield winding are wound, and the output iron core and the field iron core In any of the self-excited generators in which either one becomes a stator and the other becomes a rotor and the generated power is obtained by relative rotation between the stator and the rotor,
A rectifier is connected in parallel to the main field winding, a rectifier is connected in series to the subfield winding, and a circuit in which the subfield winding and the rectifier are connected in series is the main field winding. Only the current in the same direction as the current flowing through the main field winding is connected to the field winding in parallel with the field winding.
Per cross-sectional area of a cross section perpendicular to the rotational center of the rotor, the cross-sectional area of the sub-field winding slot the sub field winding disposed on said field core is accommodated, provided in the field core is in order not smaller than the cross-sectional area of the main field winding is main field winding slot to be included, while a self-excited, high power density can be obtained.

It is a fracture front view showing the generator main part of the generator concerning a 1st embodiment of this invention. It is explanatory drawing which expands and shows the generator main body of the generator linearly. It is a circuit diagram which shows the electric circuit structure of the generator. It is the elements on larger scale which show the main field winding slot and subfield winding slot of the generator. It is explanatory drawing of the model which performed the magnetic field analysis of the generator. It is a graph which shows the result of the magnetic field analysis of the generator. It is a fracture | rupture front view which shows the generator main body of the generator concerning other embodiment of this invention. It is a fracture | rupture front view which shows the generator main body of the generator concerning further another embodiment of this invention.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of the generator main body of the generator and an explanatory diagram combining the electric circuit diagram of the external load. FIG. 2 is a linear drawing of a pole pair of the magnetic poles of the generator main body 1 shown in FIG. A schematic diagram and FIG. 3 are electric circuits of the generator body.

  In FIG. 1, the generator includes a generator main body 1 that includes an annular stator 4 and a rotor 5 that is installed inside the stator 4 so as to be rotatable around the center of the stator 4. The stator 4 includes an output iron core 6 and an output winding 7. This embodiment is an example applied to an octupole generator, and the output iron core 6 is formed with tooth-shaped magnetic pole portions 6b protruding inward at eight locations in the circumferential direction of the annular yoke portion 6a. The output winding 7 is wound around each magnetic pole portion 6b. As shown in FIG. 2, the output windings 7 of the magnetic pole portions 6b are adjacent to each other so that different magnetic poles N and S appear on the magnetic pole surfaces facing the inner diameter side of the adjacent magnetic pole portions 6b of the output iron core 6. 6b windings are connected in series. Both ends of the output winding 7 become terminals 7a and 7b, and an external load 3 is connected to these terminals 7a and 7b as shown in FIG. 1, and current is taken out from the generator.

  The rotor 5 includes a field iron core 8, a main field winding 9 and a sub-field winding 10 wound around the field iron core 8. The field iron core 8 is provided with a plurality of tooth-shaped magnetic pole portions 8b protruding in the circumferential direction on the outer periphery of an iron core body 8a having a center hole. Similarly to the output winding 7, the main field winding 9 and the sub field winding 10 are also connected in series so that different magnetic poles N and S appear on adjacent magnetic pole faces. The sub-field winding 10 is wound at a position whose phase is advanced with respect to the main field winding 9. Terminals at both ends of each series connection body of the main field winding 9 and the sub field winding 10 are shown in FIG. 2 by reference numerals 9a, 9b, 10a, and 10b, respectively.

  As shown in FIG. 3, a rectifying element 11 is connected to the main field winding 9 in parallel. A current in a direction that allows the rectifying element 11 to flow through the main field winding 9 flows. Therefore, the main field winding 9 generates a magnetic flux only in the direction determined by the current that can be passed through the winding. In addition, due to electromagnetic induction, a current flows in a direction that prevents a decrease in magnetic flux in the same direction as a magnetic flux generated by the current, but a current does not flow in a direction that prevents an increase in magnetic flux. Therefore, the decrease of the magnetic flux is prevented, but the increase of the magnetic flux is not prevented. The secondary field winding 10 is wound out of phase with the main field winding 9 as described above. The sub-field winding 10 is connected in series with a rectifying element 12 so that only current in the same direction as the current flowing in the main field winding 9 flows. The arrows in the figure indicate the direction of current flow.

  As shown in FIG. 4 in an enlarged manner, the portion between the magnetic pole portions 8b, 8b around which the main field winding 9 is wound in the field iron core 8 is the main field winding slot 9A, and the sub field winding 10 is A portion between the magnetic pole portions 8b and 8b to be wound is a sub-field winding slot 10A. The main field winding slot 9A accommodates the main field winding 9 without a gap, and the sub field winding slot 10A accommodates the sub field winding 10 with no gap.

  In the above configuration, in this generator, the cross-sectional area of the sub-field winding slot 10A (area in the range indicated by hatching) is the cross-sectional area of the main field winding slot 9A (in the range indicated by hatching in the opposite direction to the above). Area). In this embodiment, the cross-sectional area of the subfield winding slot 10A is 7 to 40% of the cross-sectional area of the main field winding slot 9A.

  The operation of the above configuration will be described. Current flows through the main field winding 9 due to the residual magnetism of the output core 6 or the field core 8. The magnetic flux generated by the main field winding 9 caused by this current changes the magnetic flux linked to the sub field winding 10, and a voltage is generated in the sub field winding 10. With this voltage, the sub-field winding 10 supplies a current to the main field winding 9 via the rectifying element 12 to increase the current flowing through the main field winding 9. When no voltage is induced in the sub-field winding 10 and no current is supplied, a return current flows through the rectifying element 11 in the main field winding 9 and maintains the magnetic flux of the main field winding 9. Since the current is supplied to the main field winding 9 and the magnetic flux generated by the main field winding 9 is increased, the magnetic flux linked to the subfield winding 10 is also increased, and a larger current is supplied to the main field winding 9. 9 is supplied. In this way, the current in the main field winding 9 gradually increases, and a field magnetic flux necessary for power generation is created.

  The interlinkage magnetic flux of the output winding 7 is changed by the relative movement of the output iron core 6 and the field iron core 8, and a voltage is generated in the output winding 7. In this case, if the cross-sectional area of the subfield winding slot 10A is increased, the wire diameter can be increased and the electrical resistance value of the subfield winding 10 can be reduced. However, the magnetic resistance of the field iron core 8 is reduced. growing. Conversely, when the cross-sectional area of the subfield winding slot 10A is reduced, the magnetic resistance is reduced, but the wire diameter of the subfield winding 10 is reduced and the electrical resistance value is increased. The strength of the field changes depending on the balance between the magnetic resistance value and the electric resistance value. The output generated depends on the strength of the field.

  In this embodiment, as described above, the cross-sectional area of the subfield winding slot 10A is smaller than the cross-sectional area of the main field winding slot 9A. Therefore, a higher output was obtained than when the cross-sectional area of the subfield winding slot 10A was larger. In particular, when the cross-sectional area of the sub-field winding slot 10A is 7 to 40% of the cross-sectional area of the main field winding slot 9A, the highest output can be obtained and the efficiency is higher than that of other excitation generators. High power density can be obtained.

  In order to confirm the difference in output depending on the ratio of the slot cross-sectional area, magnetic field analysis was performed using the analysis model shown in FIG. This analysis model models the embodiment shown in FIG. The outer diameter φ323 mm, the stacking thickness 85 mm, and the material of the output iron core 6 and the field iron core 8 are electromagnetic steel plates. The subfield winding 10 is wound at a position where the phase is advanced. Rectifying elements 11 and 12 are connected to the field windings 9 and 10 as shown in FIG. A resistor serving as an external load 3 is connected to the output winding 7.

  The output and efficiency of the generator were calculated by changing the cross-sectional area of the sub-field winding slot 10A while keeping the number of turns of the main field winding 9 and the sub-field winding 10 constant. The result is shown in FIG. As shown in the figure, the output was highest when the cross-sectional area of the subfield winding slot 10A was 7 to 40% of the cross-sectional area of the main field winding slot 9A.

  FIG. 7 shows another embodiment of the present invention. In this embodiment, in the first embodiment shown in FIGS. 1 to 6, the output iron core 6 and the field iron core are used as the initial exciting means to such an extent that it is possible to generate a magnetic force necessary for the initial excitation of power generation. 8 is provided with magnetizing means 2 for magnetizing one or both of the iron cores 6 and 8. In the illustrated example, the magnetizing means 2 is provided so as to magnetize the output iron core 6.

  Specifically, a magnetizing power source 14 is connected to the output winding 7 in parallel with the external load 3 via the switching means 13. The magnetizing means 2 is constituted by the magnetizing power source 14 and the switching means 13. The switching means 13 is a semiconductor switching element or a contact switch. The magnetizing power source 14 is a storage means such as a secondary battery or a capacitor. When the external load 3 is a secondary battery, it may be used as a magnetizing power source.

  In order to magnetize, a current of a predetermined magnitude may be passed for a very short time. The degree of magnetization may be such that residual magnetism necessary for initial excitation for the start of power generation is obtained, and is determined by the magnitude of current and the ON time of the switching means 13. The opening / closing operation of the switching means 13 is performed by the opening / closing control means 15. For example, the opening / closing control means 15 monitors the detection signal of the rotation detection means 16 that detects the rotation of the rotor 5. When it is detected that the rotor 5 has started rotating from a stationary state, the switching means 13 is magnetized. Turn it on only for the required setting time. When the rotation stop time of the rotor 5 is short, sufficient residual magnetism remains, so that the opening / closing control means 15 turns on the switching means 13 only when the rotation starts after the rotor 5 stops for a set time or longer. For example, the switching unit 13 may be turned on according to the set conditions. Further, the magnetizing may be performed only when the power generation is not started even when the predetermined rotational speed is reached, or the magnetizing may be performed when the rotation of the generator is stopped every predetermined time. .

  As described above, power is generated while the rotor 5 is rotating. However, if the rotor 5 is stopped for a long time to some extent, there is no residual magnetism in either the output iron core 6 or the field iron core 8, Alternatively, the residual magnetism is insufficient and power generation cannot be started. Therefore, in this embodiment, at the start of the rotation after the rotor 5 is stopped, the switching means 13 of the magnetizing means 2 is turned on to pass a magnetizing current from the magnetizing power supply 14 to the output winding 7, and the output iron core 6. Magnetize. Since the magnetic flux gradually increases as the rotation continues as described above, the degree of magnetization may be such that the residual magnetism necessary for the initial excitation for the start of power generation is obtained. For this reason, in order to magnetize, a current of a predetermined magnitude may be passed for a very short time. By this magnetization, even after the rotor 5 is stopped for a long time, power generation is reliably started by resuming the rotation.

  FIG. 8 shows still another embodiment of the present invention. This embodiment is an example in which an initial excitation magnet 31 is provided as an initial excitation means in the first embodiment shown in FIGS. The initial excitation magnet 31 is obtained by embedding the initial excitation magnet 31 in the field core 8 as shown in FIG. The initial excitation magnet 31 is a permanent magnet that generates a magnetic force necessary for initial excitation of power generation, and a magnet that is as small as possible is used in a range that allows for a margin so that the magnetic force necessary for initial excitation can be reliably generated. . The initial excitation magnet 31 is a ferrite magnet that is cheaper than a rare earth magnet. The initial excitation magnet 31 has a direction in which the direction of the generated magnetic flux is the same as the direction of the magnetic flux generated by the excitation current flowing in the main field winding 9. The number of the initial excitation magnets 31 may be arbitrary or one. Further, the number may correspond to the number of magnetic poles of the output iron core 6.

  The initial excitation magnet 31 extends over the entire axial thickness of the magnetic pole portion 8b from which the field iron core 8 protrudes. In addition to this, the initial excitation magnet 31 may be embedded in a surface facing the output iron core 6 in the magnetic pole portion 8 b of the field iron core 8.

  In the case of this embodiment, even if there is no residual magnetism in the output iron core 6 and the field iron core 8 due to long-term power generation stop or the like, or the residual magnetism becomes insufficient, the magnetic flux generated by the initial excitation magnet 31 Thus, power generation is reliably started by resuming rotation. Since the initial excitation magnet 31 is a permanent magnet that generates a magnetic force necessary for the initial excitation, it may be a magnet that generates a much weaker magnetic force than a permanent magnet that obtains normal generated power. Therefore, an expensive rare metal is unnecessary, an inexpensive material such as a ferrite magnet is sufficient, a small magnet is sufficient, and the cogging torque is not a problem in practical use.

  In addition, according to the generator of each said embodiment, the following advantage is also acquired. Since it is a self-excited type that performs excitation using the main field winding 9, power generation can be performed without the need for a permanent magnet or an external power source that supplies power for external excitation from the outside. Since no permanent magnet is used, no cogging torque is generated and the rotor 5 can be rotated with a small torque.

  In each of the above embodiments, the stator 4 side is the output iron core 6 and the rotor 5 side is the field iron core 8. Conversely, the stator 4 side is the field iron core 8, and the rotor 5 side is the output iron core 6. It is also good. In the above-described embodiment, an 8-pole generator is used. However, a multi-pole generator having a multiple of 2 such as 2-pole, 4-pole, 6-pole, and 16-pole may be used.

DESCRIPTION OF SYMBOLS 1 ... Generator main body 2 ... Magnetization means (initial excitation means)
DESCRIPTION OF SYMBOLS 3 ... External load 4 ... Stator 5 ... Rotor 6 ... Output iron core 6a ... Yoke part 6b ... Magnetic pole part 7 ... Output winding 8 ... Field core 8a ... Core body 8b ... Magnetic pole part 9 ... Main field winding 9A ... Main Field winding slot 10 ... sub field winding 10A ... sub field winding slot 11 ... rectifier element 12 ... rectifier element 31 ... initial excitation magnet (initial excitation means)

Claims (3)

An output core around which an output winding is wound, and a field core around which a main field winding and a subfield winding are wound, and either one of the output core and the field core becomes a stator, In the self-excited generator that the other is a rotor and obtains generated power by relative rotation between the stator and the rotor,
A rectifier is connected in parallel to the main field winding, a rectifier is connected in series to the subfield winding, and a circuit in which the subfield winding and the rectifier are connected in series is the main field winding. Only the current in the same direction as the current flowing through the main field winding is connected to the field winding in parallel with the field winding.
Per cross-sectional area of a cross section perpendicular to the rotational center of the rotor, the cross-sectional area of the sub-field winding slot the sub field winding disposed on said field core is accommodated, provided in the field core is in the generator, characterized in that not smaller than the cross-sectional area of the main field winding slot the main field winding is accommodated.   The generator according to claim 1, wherein a cross-sectional area of the subfield winding slot is 7 to 40% of a cross-sectional area of the main field winding slot.   3. The generator according to claim 1, further comprising initial excitation means for applying a magnetic force to one or both of the output core and the field core to an extent necessary for initial excitation of power generation. .

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