JP2008005603A - Synchronous machine and power generating system using it as generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synchronous machine that makes it possible to reduce vibration, electromagnetic noise, and the like arising from torque ripples, is small in the number of wire connecting points and thus excellent in ease of miniaturization and mass productivity, and is high in operating efficiency. <P>SOLUTION: The number of field poles 9 and the number of coils 7 have the relation expressed as 10:12. Each coil 7 is of double three-phase and is constructed of first and second coil groups. The individual coils 7 contained in the first and second coil groups are alternately disposed in the direction of the circumference of a stator 2. The coils contained in the first coil group and the coils contained in the second coil group are respectively delta-connected. The coils 7 of each phase contained in the first and second coil groups are connected in series with one another on a phase-by-phase basis in the respective coil groups. The individual coils contained in the first coil group are so wound that their winding direction is opposite to that of the individual coils contained in the second coil group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a synchronous machine such as a synchronous motor or a synchronous generator that effectively reduces torque pulsation and noise, and a power generation system using the synchronous machine as a synchronous generator.

  Conventionally, in a synchronous machine, for example, a three-phase synchronous motor, load vibration and shaft torsional vibration caused by torque ripple have been a problem, and in a synchronous generator, the life of a power storage device or a smoothing capacitor caused by generated current ripple is reduced. Electromagnetic noise is a problem. In particular, the so-called 6f torque ripple having an electrical angle that is six times the fundamental wave is a problem with respect to noise and vibration in the case of a multi-polar large machine. The reason is that a multi-pole synchronous motor with a large diameter is a ring with a large diameter, so that the natural frequency is relatively lowered, while the 6f torque ripple tends to approach the audible range. For example, in a 20-pole machine, the fundamental wave becomes 200 Hz at 120 rpm, so the 6f component becomes 1.2 kHz, which is six times that, and becomes an audible range.

  In the 6f torque ripple described above, when the magnetic pole is formed by a field coil or a permanent magnet, the air gap magnetic field between the rotor and the stator becomes trapezoidal, and the third, fifth, seventh,. This is caused by the inclusion of the harmonic component of the next component. Therefore, in order to prevent the gap magnetic field between the rotor and the stator from becoming trapezoidal, on the rotor side, for example, the outer shape of the magnet is chamfered or skewed. Thus, attempts have been made to reduce the harmonic components of the odd-order components, but at the same time, the frequency of the fundamental wave is lowered, causing a problem that the output is reduced.

  Therefore, in the prior art, in order to reduce torque ripple without causing a decrease in output, there is a so-called double three-phase synchronous motor provided with two coil groups consisting of three-phase coils distributed on the stator side. It has been proposed (see, for example, Patent Document 1).

  The double three-phase synchronous motor of Patent Document 1 configured as described above can apply an output voltage having a phase difference of 60 degrees in terms of electrical angle to coils for substantially six phases, thereby reducing distortion of the voltage waveform. Therefore, harmonic components can be suppressed, and the occurrence of torque ripple can be reduced.

  However, since the electric motor described in Patent Document 1 has a coil wound in each slot in a distributed manner, the shape of the coil end portion is large, and there are limitations in reducing the size, and the two coil groups are mutually connected. Due to the overlap, there is a problem in that the coil group has a large mutual inductance and current controllability is significantly reduced.

  For this reason, in the prior art, the generation of torque ripple is further reduced, the shape of the coil end portion is small and the size can be reduced, and the mutual overlap between the two coil groups is avoided by avoiding the mutual overlap of the two coil groups. A double three-phase synchronous motor with reduced inductance has been proposed (see, for example, Patent Document 2).

  In the case of the prior art described in Patent Document 2, since the two coil groups are individually driven by an inverter, torque ripple can be reduced, and the concentrated winding method reduces the size of the coil end portion, thereby reducing the size and mass production. In addition, it is possible to obtain a coil having a low mutual inductance between coils.

Japanese Patent No. 3351258 JP-A-7-264822

  However, since the prior art disclosed in Patent Document 2 connects the two coil groups by the Y-connection method, a large number of connection points are generated. In particular, in the case of a multi-pole machine using a concentrated winding method in consideration of mass productivity, the number of teeth per phase is large, and these are often connected in parallel. That is, in the case of Y connection, since it is necessary to connect all the teeth to four electric wires of the U, V, and W phase power lines and neutral wires, a large number of connection points are generated. For example, in the case of 20 poles and 24 slots, it is necessary to connect as many as 48 locations in total, with two locations for each of the 24 coils. The connection work between the three-phase power line and each coil terminal is difficult to automate because of the handling of flexible materials such as electric wires, and it takes time if the connection work is done manually, increasing the production cost of multipolar machines. It has become a major factor.

  In addition, it is conceivable to use Δ connection instead of Y connection for cost reduction, but if Δ connection is simply performed, a loss increases because a circulating current flows for the third harmonic, In addition to reducing the efficiency of the electric motor, there is a risk of noise being generated by the third-order circulating harmonic current.

  The present invention has been made to solve the above-described problems, and reduces vibration, electromagnetic noise, or power generation ripple caused by torque ripple, and is excellent in downsizing and mass productivity, and can be applied with Δ connection. It is an object of the present invention to provide a synchronous machine that can reduce the number of places and further reduce the loss caused by the circulating current due to the third harmonic and increase the efficiency, and a power generation system using this synchronous machine.

  In order to achieve the above object, according to the present invention, the coils constituting the armature are arranged in a row in a state of being concentratedly wound around the armature core, and N and S are alternately arranged with respect to the coils of the armature. The following configuration is adopted in the synchronous machine in which the field pole is arranged.

  That is, in the present invention, at least one unit is provided with a configuration in which the relationship that the number of poles of the field pole and the number of coils is 12 ± 2 poles: 12 coils is one unit. The coil is composed of a first coil group consisting of coils for three phases and a second coil group consisting of coils for three phases, each coil included in the first coil group, and second coil group Are arranged alternately along the arrangement direction, and each coil included in the first coil group is Δ-connected, and among the coils in each phase, the coils in the same phase are connected to each other. The coils connected in series with each other and the coils included in the second coil group are Δ-connected, and among the coils in each phase, the coils in the same phase are connected in series with each other. Each coil included in the second coil group Murrell winding direction for each coil is characterized in that it is wound to have opposite.

  In the power generation system of the present invention, the first and second coil groups of the synchronous machine according to claim 1 are individually connected to a three-phase rectifier diode bridge, and the DC output of each of the three-phase rectifier diode bridges is It is characterized by being connected to power storage means for storing the output power.

  In the synchronous machine of the present invention, the phase difference in two series-connected coils in the same phase is different by 60 degrees (= π / 3), so the third order in the coil due to the third harmonic component of the field Circulated currents cancel each other out of the coils in the same phase and no longer flow. This action eliminates the useless loss caused by the circulating current due to the third harmonic, which is a problem during Δ connection. Therefore, since Δ connection by concentrated winding can be performed, the number of connection points can be reduced, the coil end portion can be reduced, the size and mass productivity can be improved, and the production cost can be reduced. Moreover, since the coils adjacent to each other in the first and second coil groups are different in electrical angle by 30 degrees (= π / 6), the fifth and seventh harmonics cancel each other, and overall Torque ripple is reduced. As a result, vibration, electromagnetic noise or power generation ripple caused by torque ripple can be reduced, and a low-noise synchronous machine can be supplied.

  Moreover, in the generator system using the synchronous machine of the present invention as a generator, by providing two coil groups of three-phase coils, a one-phase energization section during power generation is rectified by a normal three-phase diode bridge. The current can be reduced from 120 degrees energization to 60 degrees energization. For this reason, the ripple voltage is reduced and at the same time the average output is increased. As the ripple voltage is lowered, the ripple current flowing in the power storage means such as a battery or a capacitor is also reduced. As a result, in the case of in-vehicle use, it is possible to contribute to reduction of battery life and noise or light flickering to electric equipment supplied by in-vehicle power supply equipment such as radio due to ripple noise.

Embodiment 1 FIG.
1 is a cross-sectional view of a double three-phase synchronous motor as a synchronous machine according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view in which the electric motor of FIG. .

  A double three-phase synchronous motor 1 according to the first embodiment includes a stator 2 serving as an armature, and a rotor 3 disposed with a space inside the stator 2. The stator 1 has a large number (12 in this example) of slots 5 formed in an iron core 4 formed of an electromagnetic steel plate or the like, and the same number (12) of T-shapes between the adjacent slots 5. Teeth 6 are formed. A coil 7 is concentratedly wound around each tooth 6. On the other hand, in the rotor 3, a multi-pole (10 poles in this example) permanent magnet 9 which is a field pole is attached to the outer peripheral portion of the yoke 8 with N and S being alternately magnetized. Therefore, in this Embodiment 1, it is the relationship which the number of field poles: coil becomes 10:12, and the pitch between each tooth | gear 6 is 150 degree | times by an electrical angle.

  Each of the coils 7 includes a first coil group composed of three-phase coils (6 in total) of U (U1, U2), V (V1, V2), and W (W1, W2), and X (X1, X2), Y (Y1, Y2), and Z (Z1, Z2), and a second coil group consisting of three-phase coils (total of six). Then, each of six coils U (U1, U2), V (V1, V2), W (W1, W2) included in the first coil group and X (X1, X1) included in the second coil group. The six coils X2), Y (Y1, Y2), and Z (Z1, Z2) are alternately arranged along the circumferential direction of the stator 2.

  In addition, as shown in FIG. 2, in-phase coils U1, U2, V1, V2, W1, and W2 included in the first coil group are connected in series with each other. Similarly, in-phase coils X1, X2, Y1, Y2, Z1, and Z2 included in the first coil group are connected in series.

  Furthermore, each of the three-phase coils U (U1, U2), V (V1, V2), and W (W1, W2) included in the first coil group is Δ-connected. Similarly, the three-phase coils X (X1, X2), Y (Y1, Y2), and Z (Z1, Z2) included in the second coil group are also Δ-connected.

  As for the winding direction of each coil 7, all the three-phase coils U (U1, U2), V (V1, V2), and W (W1, W2) included in the first coil group are in the positive direction. Each of the three-phase coils X (X1, X2), Y (Y1, Y2), and Z (Z1, Z2) included in the second coil group is wound in a reverse direction. .

  In this manner, a double three-phase synchronous motor can be obtained by combining the 10-pole permanent magnet 9 and the 12 coils 7. In this case, the connection relationship and the electrical phase relationship of the coils 7 are summarized as shown in FIG.

  Here, the winding directions of the first coil group and the second coil group are opposite to each other, and the coils of the first coil group and the second coil group are along the circumferential direction of the stator 2. Therefore, the adjacent coils of the first and second coil groups are different in electrical angle by 30 degrees. For example, the phase of the U1 phase coil belonging to the first coil group and the X1 phase coil belonging to the second coil group adjacent thereto are different by 30 degrees. Accordingly, twelve vectors with an interval of 30 degrees are obtained for each coil 7, and the voltage phase vector relationship is as shown in FIG.

  Further, vector diagrams of the electrical phases of the coils included in the first and second coil groups when Δ connection is performed are as shown in FIGS. That is, in each of the first and second coil groups, the electrical phases of the coils for one phase connected in series are different by 60 degrees. For example, the coils U1 and U2 have a phase difference of −60 degrees when the counterclockwise direction is positive.

  As can be seen from the vector diagrams of FIG. 4 and FIGS. 5A and 5B, one phase is formed by connecting the coils 7 at two teeth positions different in phase by 60 degrees in series. Therefore, the phase difference of 60 degrees for the fundamental wave is 180 degrees, which is three times that of the third harmonic contained in the field, and can be canceled out in the in-phase coil. For this reason, even when there is a third-order harmonic of the field, the electromotive force that causes the circulating current to disappear disappears, so that Δ connection is possible.

  Incidentally, in order to contrast with the characteristics of the double three-phase synchronous motor 1 of the first embodiment, the connection state of the coil of the conventional double three-phase synchronous motor described in Patent Document 2 described above is shown in FIG. It is like 6.

  In the conventional one, two coil groups of three-phase coils are Y-connected by the concentrated winding method, so that many connection points are generated. That is, as shown in FIG. 7 (a), when Y-connection is adopted in the conventional concentrated winding, each of the three-phase coils of U, V, and W or the three-phase coils of X, Y, and Z If the winding start is taken on the power source side, the other side needs to be connected to the neutral wire side, so that the neutral wire needs to be separately arranged, and the number of wires for connection increases and the number of connection points increases. In particular, this requires a lot of labor in a multipole machine. On the other hand, when the Δ connection is performed as in the first embodiment, since the neutral line is unnecessary as shown in FIG. 7B, the connection process can be easily performed.

  Moreover, the connection relationship and electrical phase of each coil 7 in the Y-connection state shown in FIG. 6 are as shown in FIG. That is, in the conventional one, the coil 7 between the teeth 6 has a phase difference of 30 degrees and can reduce the torque ripple with respect to the sixth harmonic, but with respect to the third harmonic. Has a phase difference of 90 degrees, has no ripple reduction effect, causes a loss due to an annular current, and reduces the efficiency of the motor. On the other hand, in the first embodiment, Δ connection is performed. As described above, the electrical phase of coils for one phase connected in series with each other is different by 60 degrees. The phase difference of 180 degrees, which is three times that of the wave, is canceled by the third-order circulating current in the coil caused by the third-order harmonic component of the field, being canceled in the in-phase coil.

  Further, in the conventional device, as shown in FIG. 8, the winding direction is normal, reverse, reverse, normal, normal, reverse, reverse,..., And each phase coil U (U1) included in the first coil group. , U2), V (V1, V2), W (W1, W2), the winding directions are normal and reverse, and coils X (X1, X2), Y of each phase included in the second coil group As for (Y1, Y2) and Z (Z1, Z2), the winding direction exists between the forward and reverse directions. For this reason, it takes time to wind the coil 7. In contrast, in the first embodiment, as shown in FIG. 3, coils U (U1, U2), V (V1, V2), W (W1, W1) of each phase included in the first coil group. W2) is all in the positive direction only, and coils X (X1, X2), Y (Y1, Y2), and Z (Z1, Z2) of each phase included in the second coil group are only in the reverse direction. That is, since the winding directions of the coils 7 belonging to the same coil group are all the same, automation in Δ connection during continuous winding is extremely easy.

  As described above, the double three-phase synchronous motor 1 according to the first embodiment has a field because the phase difference between two series-connected coils in the same phase differs by 60 degrees (= π / 3). The third-order circulating current in the coil caused by the third-order harmonic component is canceled out in the in-phase coil and stops flowing. By this action, useless loss caused by the circulating current due to the third harmonic, which is a problem at the time of Δ connection, is eliminated. Thereby, since Δ connection by concentrated winding can be performed, the number of connection points can be reduced, the coil end portion can be reduced, and the size and mass productivity can be improved, and the production cost can be reduced.

  In addition, since the adjacent coils of the first and second coil groups are different in electrical angle by a phase difference of 30 degrees (= π / 6), the fifth and seventh harmonics cancel each other, and the overall Torque ripple is reduced. As a result, vibration, electromagnetic noise or power generation ripple caused by torque ripple can be reduced, and a low-noise synchronous machine can be supplied.

  In the first embodiment, the case where the number of poles and the number of coils is 10 poles: 12 coils is shown. However, if the number of poles is not equal to the number of coils, any combination of poles: the number of coils is established. Even if it is limited to a three-phase motor, for example, other combinations such as 8 poles: 9 coils, 32 poles: 30 coils are established. However, the combination of 6 ± 1 poles: 6 coils as one unit is most advantageous in order to obtain a double three-phase (six-phase) tooth pitch of 150 ° or 30 ° in electrical angle. Actually, the odd pole motor is possible with the linear type, but it is not realistic with the rotary motor, and it is necessary to use the even pole, so it is configured with 10 poles: 12 teeth as one unit as in this example. Or 14 poles: 12 teeth are preferably configured as one unit.

Further, the double three-phase synchronous motor 1 of the first embodiment can also obtain the following secondary effects.
That is, this synchronous motor has a structure having two systems of three-phase circuits, but an inverter circuit for driving the same is often modularized for three phases. Therefore, since they can be used as they are, the circuit configuration is easy. In addition, since the mutual inductance between the coils is small, two existing three-phase sensorless control controllers are provided in each of the U, V, and W phase coils and the X, Y, and Z phase coils, thereby reducing ripples. It becomes possible to drive to.

  In addition, since the double three-phase synchronous motor 1 of the first embodiment has a least common multiple of the number of poles and the number of coils, the cogging is small and does not affect the torque ripple. Further, since the ratio between the pitch of the field pole and the arrangement pitch of the coil is close to 1, most of the generated magnetic flux of the permanent magnet 9 is effectively linked to the coil, and a large torque can be generated with a small current. Low loss and high efficiency. Further, since the coils 7 are arranged at an equal pitch, a three-phase unbalance is not caused, and therefore a normal three-phase motor control method can be applied as it is. In addition, although it has a double three-phase configuration, the degree of mutual coupling is also small magnetically. Therefore, when either one of the first and second coil groups fails, the output is limited, but the operation can be continued using the remaining three-phase coil groups, so the fail-safe property is high.

Embodiment 2. FIG.
FIG. 9 is a circuit configuration diagram showing a main part of the power generation system according to the second embodiment when the synchronous machine having the double three-phase configuration of FIG. 1 is used as a generator.

  In the second embodiment, the first coil group for U, V, W3 phases and the second coil group for X, Y, Z3 phases constituting the synchronous machine 1 shown in FIG. The three-phase rectifier diode bridges 11 and 12 are connected to each other, and the DC output of each of the three-phase rectifier diode bridges 11 and 12 is connected to a storage means 13 such as a battery or a capacitor that stores the output power. This type of combination is often used in combination with a battery as a power storage means in a generator that operates at a constant speed, for example, a diesel private generator.

  FIG. 10 shows the three-phase voltage waveforms before rectification when a normal synchronous generator having three-phase coils of U, V, and W is connected to one three-phase rectifier diode bridge, and FIG. 10 shows the DC voltage waveforms after rectification. As shown in FIG. As shown in FIG. 10, the sine waveform is such that the energized phase is switched every 60 degrees before rectification, but when this sine waveform is rectified, a ripple component having a frequency six times the fundamental wave appears as shown in FIG. . When a waveform including this ripple voltage is connected to power storage means such as a battery or a capacitor, a ripple current flows and heat is generated, and the life is shortened.

  On the other hand, like this Embodiment 2, the 1st coil group for U, V, and W3 phases which comprise the generator 1 shown in FIG. 1, and the 2nd coil for X, Y, and Z3 phases FIG. 12 shows double three-phase voltage waveforms before rectification, and FIG. 13 shows DC voltage waveforms after rectification when two groups of independent three-phase rectifier diode bridges 11 and 12 are connected. As shown in FIG. 12, before the rectification, a sinusoidal waveform in which the energized phase is switched every 30 degrees is obtained, and when this sine waveform is rectified, a ripple component having a frequency 12 times the fundamental wave appears as shown in FIG. As compared with the case shown in FIG. 11, the amplitude of the ripple is lowered.

  As a result, the ripple current is reduced and the life of the power storage means 13 is extended. In addition, problems such as electromagnetic noise and electromagnetic noise due to ripple current can be avoided. In addition, since the current-carrying section is as narrow as 60 degrees to 30 degrees of a normal three-phase rectifier diode, only the high portion near the peak of the sinusoidal line voltage is used, so that the average power output also increases. can get.

  Further, the generator 1 has high productivity because the coil 7 of the stator 2 is concentrated winding, and the power generation efficiency is high because the conductor space factor of the coil 7 can be increased. As a result, when a battery is used as the power storage means 13, a power generation system having a good characteristic that the lifetime is extended, there is no problem such as noise, and noise is low is obtained.

  The present invention is not limited to the configurations of the first and second embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the synchronous motor and the synchronous generator shown in the first and second embodiments, the coil 7 is wound around the tooth 6 for convenience of explanation, but the slotless electric motor without the tooth 6 is shown. Can also be applied. Furthermore, the present invention can be applied not only to a rotary synchronous motor but also to a linear synchronous motor.

It is sectional drawing of the double 3 phase synchronous motor as a synchronous machine in Embodiment 1 of this invention. FIG. 2 is a cross-sectional view in which the electric motor shown in FIG. 1 is developed linearly to show a connection state. It is explanatory drawing which shows the connection relation of each coil in the double 3 phase synchronous motor of Embodiment 1, and the relationship of an electrical phase. In the double three-phase synchronous motor of Embodiment 1, it is explanatory drawing which displayed the relationship of the electric phase of each coil contained in the 1st, 2nd coil group by the vector. In the double three-phase synchronous motor of Embodiment 1, it is explanatory drawing which displayed the relationship of the electrical phase of each coil contained in the 1st, 2nd coil group which carried out (DELTA) connection by the vector. In order to contrast with the present invention, it is a cross-sectional view in which a conventional double three-phase synchronous motor is developed linearly to show a connection state. It is explanatory drawing which compares and shows the state of (DELTA) connection and Y connection. It is explanatory drawing which shows the connection relationship of each coil and the relationship of an electrical phase in the conventional double 3 phase synchronous motor shown in FIG. It is a circuit block diagram which shows the principal part of the electric power generation system in this Embodiment 2 at the time of using the synchronous machine of the structure of the double 3 phase of FIG. 1 as a generator. It is a wave form diagram which shows the electric power generation voltage of the conventional three-phase synchronous generator. FIG. 11 is a waveform diagram showing a DC voltage waveform after the voltage waveform shown in FIG. 10 is rectified by a three-phase rectifier diode bridge. It is a wave form diagram which shows the electric power generation voltage at the time of using the synchronous machine of the structure of the double 3 phase of FIG. 1 as a generator. FIG. 13 is a waveform diagram showing a DC voltage waveform after the voltage waveform shown in FIG. 12 is rectified by a three-phase rectifier diode bridge.

Explanation of symbols

1 Double 3-phase synchronous motor (synchronous machine) 2 Stator 3 Rotor 5 Slot
6 teeth, 7 coils, 9 permanent magnets, 11, 12 three-phase rectifier diode bridge, 13 power storage means.

Claims (2)

Each coil constituting the armature is arranged in a row in a state of being concentratedly wound around the armature core, and is a synchronous machine in which field poles are alternately arranged N and S for each coil of the armature,
The structure in which the number of field poles and the number of coils is 12 ± 2 poles: 12 coils is provided for at least one unit, and each of the coils included in one unit has three phases. Each coil included in the first coil group, each coil included in the second coil group, and each coil included in the second coil group. Are alternately arranged along the arrangement direction, and each coil included in the first coil group is Δ-connected, and among the coils of each phase, the coils of the same phase are connected in series with each other. In addition, each coil included in the second coil group is Δ-connected, and among the coils of each phase, the coils in the same phase are connected in series with each other, and each coil included in the first coil group is For each coil included in the second coil group Synchronous machine, characterized in that the direction is wound to have opposite winding. The first and second coil groups of the synchronous machine according to claim 1 are individually connected to a three-phase rectifier diode bridge, respectively, and the DC output of each of the three-phase rectifier diode bridges is a storage means for storing the output power. A power generation system characterized by being connected.

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