JP2014064444A - Separately excited variable reluctance power generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separately excited variable reluctance power generator in which generated voltage and frequency per rotation are large and which can control output voltage from outside.SOLUTION: In a multi-pole type variable reluctance power generator, a plurality of small magnetic pole teeth are arranged on confronted faces of both end outer peripheries of a rotor and an inner periphery of a stator, and voltage and a frequency per rotation are increased. Excitation winding controllable from outside is installed in a center of the stators with both poles. Magnetic flux can be controlled and output voltage can be controlled from the outside and cogging torque at the time of starting can be reduced.

Description

The present invention relates to an excitation variable reluctance generator having a large generated voltage and frequency per rotation and capable of controlling its output from the outside.

In existing generators driven by water turbines or wind turbines that are used in a relatively small low speed range of several tens of rpm, the speed increases to generate a stable voltage of 10 V or more required for battery chargers. It was necessary to increase the speed with the machine.

This increases the overall weight of the generator and causes a reduction in efficiency and a price increase due to the gearbox. In addition, in a DC generator, the brush life is short and the efficiency decreases due to friction. , It was difficult to use with small water turbines or windmills.

In addition, a semiconductor inverter used as a high-frequency power source for a small-sized high-frequency heating apparatus of about several kW has a large device and is expensive, and there is a possibility that electromagnetic interference due to switching noise occurs.

In order to deal with these problems, the stepping motor may be driven from outside to be used as a generator, but the generated voltage cannot be controlled because the rotor is excited by a permanent magnet. There are drawbacks that unnecessarily high voltages are generated at high speeds, the coking torque at startup is large, and that the permanent magnets account for the total price of the generator as the size increases, making it difficult to obtain. It was.

JP 11-313473 A JP 2000-60092 A JP 2011-259633 A

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Challenges to solve the challenges

In conventional DC and AC generators, the number of poles per revolution is small, the generated voltage and frequency in a low speed range of about several tens of rpm are low, and the target voltage is increased by a speed increaser or by a multipolar generator. However, the size of the gearbox increased the weight and the price as the outer size increased, and the efficiency and noise generation due to the gearbox could not be avoided. .

In addition, in this type of small generator driven by a small water wheel or windmill, the rotational speed of the water wheel or windmill driving the power generator varies greatly within a range of 2 to 5 times. On the other hand, the allowable input voltage range for chargers is usually about 1.5 times, so if this required maximum voltage is exceeded, not only the corners and the generated power can be used effectively, but also the charger is damaged. There was a fear.

As a small generator, a stepping motor such as [Patent Document 1] and a commercially available PM or HB type stepping motor may be driven from outside to generate power, but these are excited by a permanent magnet, so that the generated voltage is controlled. In addition, the starting torque due to coking is large, and when it is used for a windmill, the starting wind speed (cut-in wind speed) increases, and when the stepping motor is enlarged, a large permanent magnet is required. However, it was difficult to obtain and had the disadvantage of increasing the price.

In addition, in a multi-pole generator such as [Patent Document 2], the number of poles of the permanent magnets and windings is large, the structure is complicated, and the outer diameter is increased. , Which caused the increase in size and price.

The reluctance generator of [Patent Document 3] is difficult to increase the number of poles because of its structure, and since the strength of the magnetic field is constant, the coking torque, that is, the starting torque is large, and is used for wind power generation, etc. However, there was a drawback that the startup wind speed (cut-in wind speed) was increased.

In addition, since the number of poles is still small, the voltage and frequency during low-speed rotation are low, and it is necessary to increase the speed of wind power and hydroelectric power generators for charging storage batteries.

In addition, the generators [0010] to [0012] described above are excited only with permanent magnets, and the output voltage is almost proportional to the number of revolutions. Unnecessary power generated at the rotation speed could not be suppressed, resulting in a decrease in energy use efficiency, and a charger with a wide input voltage range was required to charge storage batteries.

In addition to the above-mentioned patent documents, semiconductor inverters are used as high-frequency power supplies for high-frequency heating equipment of several kW, such as quenching, tempering, soldering, soldering, and resin coating. It is large and expensive, and there is a risk of electromagnetic interference due to switching noise.

Means for solving the problem

In order to solve these problems, in the present invention, a plurality of rotor small magnetic pole teeth are equally disposed along the circumferential direction on the stator-facing inner surfaces of both ends of the rotor, The phases of the small magnetic pole teeth are phase-shifted by the same phase or (π / number of phases) radians, and stators each wound with a winding are arranged radially on the outer circumference of each rotor. In the variable reluctance generator having a plurality of pairs of stators each formed with one or more small magnetic pole teeth on the inner peripheral surface facing each other, the outer periphery is formed at the axial center between the S and N stator rings. The generated voltage can be controlled by winding an excitation winding with a ring-shaped yoke and exciting it from the outside.

Effect of the invention

The generator of the present invention can increase the generated voltage and frequency by increasing the number of poles of the generator and increasing the rate of change of magnetic flux.

Furthermore, it is possible to control the generated power to an arbitrary value by exciting the above generator from the voltage control device to make it an excitation generator, and the coking torque can be reduced by reducing the excitation current at start-up, so that it is small Start-up with start-up torque can be realized.

This means that, as a small wind and hydraulic power generator, it is possible to provide a generator with a simple structure, small size and light weight, low starting torque, and stable and easy output control from low speed to high speed. it can.

In addition, high-frequency generators such as high-frequency heating equipment that can control power from the outside without quenching, tempering, brazing, soldering, resin coating, etc., without electromagnetic interference, by driving the above-mentioned generator at high speed. Can provide.

Sectional view of the generator of the present invention in the case of 8-pole 2-phase Detailed view showing the relationship of the magnetic poles of the rotor part of the generator of FIG. The enlarged view which shows the positional relationship of the rotor of the EE cross section of the generator of FIG. 1, and the magnetic pole tooth of a stator. The enlarged view which shows the positional relationship of the rotor of the FF cross section of the generator of FIG. 1, and the magnetic pole tooth of a stator. Example of connection diagram of generator capable of output control in case of two phases

In a general generator, the generated voltage is proportional to the number of coil turns, the amount of change in the magnetic flux crossing the coil, and the rate of change over time, and the frequency is the rotational speed and the number of poles arranged all around. Is proportional to the product of

The present invention provides a ring-shaped magnetic pole having a plurality of small magnetic pole teeth on the outer periphery at both ends of the rotor separated in the axial direction, and a plurality of each on the inner peripheral surface facing the stator and facing the magnetic pole teeth. A plurality of pairs of stator magnetic poles formed with small magnetic pole teeth, and a stator having individual windings of the stator magnetic poles, and by increasing the substantial number of poles, In a variable reluctance generator in which the time change rate of the drive shaft is increased and the generated voltage and frequency for one rotation of the drive shaft are increased, a ring-shaped excitation winding is provided on the inner periphery in the axial center of the stator. The rotor is excited in the axial direction from the outside to control the strength of the magnetic flux.

FIG. 1 is a cross-sectional view of an example of a generator in the case of the 8-pole 4-pair 2-phase of the present invention, and is a cross-sectional view of a basic form showing an example in which a winding is wound around each stator. As shown in (a), the outer periphery of both ends of a rotor core 4 made of a magnetic material with a relatively low conductivity and a high magnetic permeability attached to a drive shaft 1 rotatably supported by a housing 3 via a bearing 2 In FIG. 2, small magnetic teeth 10 and 11 are arranged as shown in FIG.

In this case, the mutual angle of the magnetic pole teeth of the rotor poles is phase-shifted by (π / number of phases) radians of the phase angle of the mechanical angle as shown in FIG.

On the other hand, a plurality of pairs of stator cores 6 to 9 having a plurality of magnetic pole teeth having the same pitch as the magnetic pole teeth of the rotor are arranged on the inner peripheral surface of the stator corresponding to the rotor magnetic pole teeth at both ends. . In this case, the number of magnetic pole teeth on the inner circumference of the stator core is 1 or more, and is one or more less than the integer value obtained by dividing the number of rotor magnetic pole teeth by the number of stator poles.

Further, the stator windings of each phase are divided in half in the axial direction, and an excitation winding 18 having a yoke 5 on the outer periphery is incorporated in the center thereof, and this excitation winding is controlled from the outside. As shown in FIG. 1A, for example, the rotor core 4 has a strength substantially proportional to the excitation current in the axial direction, such as the N pole on the right side and the S pole on the left side. It is magnetized by.

3 and 4 are enlarged views showing the positional relationship of the magnetic poles at the same rotational angle position of the generator when the angle between the magnetic pole teeth 10 and 11 at both ends of the rotor is shifted by 1/2 pitch. As shown in the EE cross-sectional view of FIG. 4, in the S pole, the magnetic pole teeth 12 of the four S pole A phase stator cores 6 and the S pole rotor magnetic pole teeth, which are arranged at positions that equally divide the circumference. 10, there is no phase shift, and therefore the A-phase magnetic resistance is minimized, while the S-pole B-phase stator pole teeth 14 and the S-pole rotor pole teeth of the four S-pole B-phase stator cores 8. 10 is that the mechanical phase is shifted by 1/2 pitch, so the B-phase magnetic resistance is maximized.

At this rotational position, as shown in the FF cross-sectional view of FIG. 4, in the N pole, the magnetic pole teeth 15 of the four N pole B phase stator cores 9 and the N pole rotor magnetic pole teeth 11 are out of phase. The magnetic resistance of the B phase is minimized, while the N pole A phase stator pole teeth 13 and the N pole rotor pole teeth 11 of the four N pole A phase stator cores 7 have a mechanical phase. Since it is shifted by 1/2 pitch, the magnetic resistance of the A phase is maximized.

Accordingly, at this rotational position, the rotor core 4-N pole rotor magnetic pole teeth 11 → N pole B phase stator magnetic pole teeth 15 → N pole B phase stator core 9 → relay 5 → S in FIG. The magnetic flux flowing from the pole A phase stator core 6 to the S pole A phase stator pole teeth 12 to the S pole rotor pole teeth 1 to the rotor core 4 is maximized, while the N pole A phase stator core 7 and S The magnetic flux flowing through the pole B phase stator pole teeth 14 is minimized.

Although not shown, if the rotor rotates 1/2 pitch in the mechanical phase from this state, on the S pole side, the A-phase pole teeth are shifted by 1/2 pitch and the magnetic resistance becomes maximum, and B The magnetic pole teeth of the phase have no deviation, so the magnetic resistance is minimized. Therefore, the magnetic flux flowing through the S pole A phase stator core 6 is minimized, and the magnetic flux flowing through the S pole B phase stator core 8 is maximized.

On the other hand, on the N pole side, the A phase magnetic pole teeth have no phase shift, and the B phase magnetic pole teeth have a mechanical phase shift of 1/2 pitch. Magnetoresistance is maximized. Therefore, the magnetic flux flowing through the N-pole A-phase stator core 7 is maximized, the magnetic flux flowing through the N-pole B-phase stator core 9 is minimized, and the maximum value and the minimum value of the magnetic flux flowing through each stator are expressed by this change. The direction of increase / decrease of the magnetic flux between is opposite to the aforementioned [0030].

Thus, when the rotor makes one rotation, the change in the magnetic flux passing through the stator magnetic poles of each phase is repeated between the maximum value and the minimum value by the number of teeth of the rotor magnetic pole teeth. In the stator winding wound around the iron core, an alternating voltage of opposite phase is generated in the A phase and the B phase, and the magnitude of the alternating voltage generated in each stator winding is as follows. When the magnetic flux is constant, (variation of magnetic flux) x (temporal change rate of magnetic flux) x (number of turns of stator winding), ie, (variation of magnetic flux) x (number of teeth of rotor magnetic pole teeth) ) X (total number of stator windings), and its frequency is also proportional to (number of rotor pole teeth) x (number of revolutions). For example, even at a low speed of 100 rpm, a high frequency close to the commercial frequency (30 Hz in the figure) can generate an alternating voltage with a high phase A and phase B higher than 10V, and it can be driven at 2000 rpm. In this case, power with a frequency of 600 Hz can be obtained, and power with a higher frequency can be obtained by increasing the number of magnetic pole teeth.

In contrast to FIG. 2, when the mutual angle of the magnetic pole teeth of the rotor poles is not shifted and in phase, the phase relation of the magnetic pole teeth in both poles is the same, that is, EE at the rotational position value in FIG. The phase relationship between the cross sections is the same for both the S pole and the N pole as shown in FIG. 3. In this case, the magnetic pole teeth 12 of the S pole A phase stator core 6, the S pole rotor magnetic pole teeth 10, and the N pole A phase stator. Since both the magnetic pole teeth 13 of the iron core 7 and the N pole rotor magnetic pole teeth 11 are not out of phase, the magnetic resistances of all the A phases are minimized, while the magnetic pole teeth 14 and the S poles of the S pole B phase stator core 8 are minimized. The magnetic pole teeth 15 of the rotor magnetic pole teeth 10 and the N-pole B-phase stator core 9 and the N-pole rotor magnetic pole teeth 11 have a phase shift of ½ pitch, and the magnetic resistances of all the B phases are maximized. From this state, when the rotor rotates 1/2 pitch, all the A-phase magnetoresistances become maximum, while all the B-phase magnetoresistances become maximum.

When the rotor makes one rotation from this state, the windings on the same-phase N and S stators are all alternating with the A and B phases being in proportion to the rate of change of the magnetic flux, as in [0033]. A voltage is induced. Therefore, by connecting these A-phase and B-phase windings in opposite phases, a high voltage can be obtained even at a low speed.

As described above, the operation and effect of the generator example in the case of the 8-pole 4-pair 2-phase described in [0024] to [0035] is that the phase between the small magnetic pole teeth at both ends of the rotor is the same phase or (π / Number of phases) The number of phases and the number of phases can be increased by arranging the stators, each of which has a phase shift of radians, or twice the even number of phases, that is, the same number of pole pairs as the number of phases and wound with windings. It can be demonstrated regardless of the number of pole pairs.

In addition, since the coking torque is caused by the attractive force between the magnetic poles, it affects only at the time of start-up, and after starting once, the repulsive force and the attractive force cancel each other and the influence of coking is eliminated. In the case of wind power generation, etc., it is necessary to be able to start at as low a wind speed as possible. However, in the case of the present invention, at the time of start-up, it is excited by only the residual magnetic flux and the excitation current is small, so the coking torque at start-up can be reduced. There is.

FIG. 5 is an example of a connection diagram for stabilizing the output voltage constant. By the excitation current obtained by comparing the DC output voltage rectified by the rectifier 25 and the set voltage by the voltage setter 24 by the voltage regulator 23, This circuit controls the set voltage. By changing the control characteristics in the voltage regulator 23, not only constant voltage control or constant current control, but also outputs corresponding to various load characteristics can be obtained. By slowing the rise of the excitation current, the coking torque can be reduced and the starting torque can be reduced.

Further, by performing the voltage control described above, it is possible to prevent the occurrence of energy loss when the voltage is higher than necessary, so that the power of the drive source can be used effectively.

In the above, the case where the DC output is mainly used has been described. However, it is also possible to use the AC output of the generator as it is by using a similar excitation circuit and use it as a high frequency generator.

Usually, small hydroelectric power generators, wind power generators, etc., have a rotational speed of about several 60 rpm, and the range of change in the rotational speed is large. On the other hand, as a generator used for this, a voltage of 10 V or more such as charging of a storage battery is stable. Needed to occur. For this purpose, it was necessary to combine a gearbox, or to connect a special generator with an extremely large number of poles or several generators in series, but it was large, heavy and expensive. In particular, it was difficult to use self-floating hydroelectric generators and pole-mounted wind generators.

According to the generator of the present invention, there is no such adverse effect, and a smoothing circuit can be simplified since a sufficient voltage of a frequency close to the commercial frequency can be obtained even at a low rotation speed with a small size and light weight. , High utility value for small water turbine or windmill.

In addition, by driving the generator of the present invention at high speed with an electric motor or engine, high frequency AC power can be obtained, which is subjected to high frequency heating such as quenching, tempering, brazing, soldering, and resin coating. It can be used as a high frequency power supply in place of the inverter type high frequency power supply of equipment.

DESCRIPTION OF SYMBOLS 1 Drive shaft 2 Bearing 3 Housing 4 Rotor core 5 Relay 6 S pole A phase stator core 7 N pole A phase stator core 8 S pole B phase stator core 9 N pole B phase stator core 10 S pole rotation Slave pole teeth 11 N pole rotor pole teeth 12 S pole A phase stator pole teeth 13 N pole A phase stator pole teeth 14 S pole B phase stator pole teeth 15 N pole B phase stator pole teeth 16 A phase winding 17 B phase Winding 18 Excitation winding 19 S pole A phase winding 20 N pole A phase winding 21 S pole B phase winding 22 N pole B phase winding 23 Voltage regulator 24 Voltage setter 25 Rectifier 26 Capacitor 27 Discharge resistor 28 load

Claims (1)

A plurality of rotor small magnetic pole teeth are equally distributed along the circumferential direction on the inner surface facing the stator at both ends of the rotor, and the phase between the small magnetic pole teeth at both ends is the same phase or ( π / number of phases) In a pair of radiant phase-shifted rotor cores, stators wound with windings are radially arranged on the outer periphery, and on the inner peripheral surface facing each rotor, In a variable reluctance generator having a plurality of pairs of stator small magnetic poles each formed with one or more small magnetic pole teeth, a ring-shaped yoke is provided on the outer periphery at the center in the axial direction between the S and N stator rings. A separately-excited variable reluctance generator that can control the generated voltage by winding an excitation winding with

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