JP2008263738A - Rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary electric machine having a structure hardly influenced by magnetic interference of each of phases and reducing cogging torque to cause torque ripple in order to solve the problem that a coupled core external circumference of a stator magnetic pole causes electric interference on each of the phases and a control constant of a controller to be driven is influenced by the other phases, resulting in less controllability in a conventional technique, and further, to reduce the cogging torque to cause torque ripple in the structure of a rotor. <P>SOLUTION: This rotary electric machine has a profile in which the magnetic poles can be separately disposed. In the electric machine, two magnets 3a, 3b of the rotor are disposed with a phase difference by an electric angle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine.

  As a conventional rotating electrical machine in which windings of respective phases are arranged in the circumferential direction, a stator structure in which a coil is wound around a stator magnetic pole as disclosed in JP-T-2005-532775 is disclosed. Further, in the conventional motor, the magnetic poles could not be divided because there was a magnetic flux interlinking the outer periphery of the core back in the circumferential direction.

JP 2005-532775 A

  In the conventional technology, since the core outer peripheral part of the stator magnetic pole is connected, magnetic interference occurs in each phase, and the control constant of the controller to be driven is influenced by other phases, so that the controllability is improved. There are missing issues. Furthermore, it is necessary to further reduce the cogging torque that causes torque ripple in the structure of the rotating machine of the present invention.

  An object of the present invention is to provide a rotating electrical machine that is less susceptible to magnetic interference between phases and that can reduce the cogging torque that causes torque ripple.

  In the present invention, the magnetic poles of each phase can be divided and arranged. Further, the two rows of magnets of the rotor are arranged with an electrical angle and a phase difference.

  It is possible to provide a rotating electrical machine that has a structure that is difficult to receive magnetic interference of each phase and can reduce cogging torque that causes torque ripple.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows one embodiment of the present invention in which stator magnetic poles are magnetically arranged in three phases independently, and the permanent magnets of rotor magnetic poles are configured in two rows. The rotor has 24 poles. With this structure, the three-phase stator (stator magnetic pole) is divided so that it is difficult to receive the magnetic interference of each phase. Since the control constant is affected by other phases, the problem of lack of controllability can be solved.

  Next, the configuration will be described in detail. In the rotor 100, the shaft 1 is disposed at the center, and the rotor yoke 2 is disposed on the outer periphery of the shaft 1. A permanent magnet 3 is disposed on the outer periphery of the rotor yoke 2. The permanent magnet 3 is composed of two ring magnets, permanent magnets 3a and 3b. As shown in the figure, the permanent magnets 3a and 3b are configured such that the phase of the magnetized magnetic pole has an electrical angle and a phase difference. Originally, a support mechanism such as a case and a bearing is necessary as a motor, but it is omitted in this figure. Next, the stator 200 will be described. Three magnetic poles are arranged on the outer peripheral portion of the permanent magnet 3 of the rotor via a slight gap so that the stator magnetic pole has a phase difference of three phases. The three-phase stator magnetic poles are a U-phase magnetic pole 4U, a V-phase magnetic pole 4V, and a W-phase magnetic pole 4W, and are arranged so as to substantially overlap the magnet 3 of the rotor. A stator coil is arranged at the center of each phase magnetic pole, the U phase coil is indicated by 5 U, the V phase coil is indicated by 5 V, and the W phase magnetic pole is indicated by 5 W. Furthermore, each phase coil forms a coil end portion in a U shape at the end of the stator magnetic pole, and lead wires 10U, 10V (not shown) and 10W are connected to an external drive circuit (not shown) from the coil end portion. Connected. In such a stator configuration, each stator magnetic pole is arranged on the outer periphery of the rotor with a phase difference of 120 degrees in electrical angle by a connecting material (not shown). The connecting material may have any structure as long as it can mechanically fix the stator magnetic poles of each phase, and is preferably composed of a nonmagnetic metal. Further, after being connected, it may be molded into a cylindrical shape by resin.

Details of the stator magnetic pole 4U described in FIG. 1 will be described with reference to FIG. Since the other phases, 4V and 4W, have the same structure, description thereof is omitted. As described above, the U-phase magnetic pole 4U is composed of five parts. The stator magnetic pole 4U is composed of two magnetic pole rows of 4Ua and 4Ub. For example, the 4Ua magnetic pole array is composed of magnetic pole teeth 4Ua1 arranged toward the inner peripheral side and 4Ua2 arranged outwardly. It is comprised so that it may be inserted | pinched. Furthermore, the other coil of the U-phase coil 5U is sandwiched between the central portions of 4Ub1 and 4Ub2 constituting another magnetic pole row 4Ub. The lead wire 10U of the U-phase coil 5U is taken out from a U-shaped coil end portion that is not sandwiched between magnetic poles.

  FIG. 3 (a) shows a structure in which a U-phase coil 5U is sandwiched between 4Ub rows of U-phase magnetic poles described above. The 4Ua row of magnetic poles are arranged in the coil portion in front of the page. FIG. 3B shows a magnetic pole at the center of the coil around which the U-phase coil 5U is wound. The U-phase coil 5U may be wound directly around the illustrated outward-facing magnetic pole teeth 4Ua2 and 4Ub2, or a coil formed in advance in a ring shape may be disposed. It is also possible to manufacture 4Ua2 and 4Ub2 integrally.

FIG. 4 shows a completed view of the U-phase magnetic pole 4U. As described above, the U-phase coil 5U is arranged at the center of the magnetic pole array composed of two rows. As can be seen from the figure, the magnetic pole teeth constituting the magnetic pole row 4Ua are formed in the same shape. Similarly, the other magnetic pole row 4Ub is formed of substantially the same shape.

  FIG. 5 (a) shows a view in which a notch 7 is provided in the portion between the magnetic poles that overlaps the tip portions of the outward magnetic pole teeth 4Ua2 and 4Ub2 of the U-phase magnetic pole 4U described above. The shape of the notch 7 is a circle or a rectangle, and the width W2 of the notch 7 is narrower than the width W1 between the magnetic poles, and preferably equal to the tip width W3 of the magnetic pole teeth. Here, the reason why the notch portion 7 is provided is that the distance from the claw tip portion to the portion between the magnetic poles is increased, and therefore, in addition to the reduction of the leakage magnetic flux from the claw tip portion, there is an effect of reducing the coil inductance. In this case, the generated current can be increased, and in the case of a motor, the motor voltage can be reduced. FIG. 5B shows another embodiment in which the same effect can be expected. FIG. 5B is a view in which a hollow portion 8 is provided between the magnetic poles. Although the effect of reducing leakage magnetic flux from the claw tip cannot be expected as an effect, the mechanical strength can be increased because the coil inductance is reduced and the inner peripheral side between the magnetic poles is connected. Furthermore, you may comprise combining these two. Other methods of using these notches 7 and cutouts 8 will be described. As described above, since the three-phase magnetic poles are magnetically separated, it is necessary to fix them in the radial direction and the circumferential direction. Furthermore, it is necessary to ensure an electrical phase difference with high accuracy as a three-phase rotating electrical machine. Therefore, it is possible to fix the cutout portion 7 and the cutout portion 8 by using them for positioning. The size of the cut-out portion 8 is preferably about W1 between the magnetic pole widths even if it is large if the width of the cut-out portion is W4 as in the above-described notch portion.

  Next, a cogging torque reduction method that is an object of the present invention will be described. FIG. 6 is a view in which the U-phase magnetic pole 4U of the claw pole type rotating electric machine shown in FIG. 1 is omitted. Ring-shaped permanent magnets 3 arranged in two rows are arranged on the rotor. The permanent magnets 3a and 3b overlap the stator magnetic poles 4Va and 4Vb, respectively. The permanent magnets 3a and 3b have a phase difference in magnetization. Since the N pole and S pole of the permanent magnet are electrically 360 degrees, in this embodiment, a phase difference of 30 degrees was given in terms of electrical angle. The reason is that in the case of a three-phase motor, six cogging torques are generated per rotation. That is, the force changes with an electrical angle of a cycle of 60 degrees. This force variation is caused by the cogging torque and the magnetic pole shape. This cogging torque acts as a disturbance torque when the motor is driven and causes speed fluctuations and torque pulsations. If this cogging torque is large, it is difficult to tune the control system, and there is a problem that positioning is impossible in the initial excitation mode when performing sensorless driving, and rotation may be impossible. In the motor structure of the present invention, as shown in FIG. 6, the permanent magnets and the stator magnetic poles are composed of two rows and are symmetrical in the center of the axis. By paying attention to this structure, it is realized by arranging in a phase that cancels the phase of the cogging torque generated in the opposite row to the phase of the cogging torque on one side. As described above, in this structure, a cogging torque of 60 degrees in electrical angle is generated. Therefore, the phase of the permanent magnet is shifted by 30 degrees so that the cogging torque in the opposite row has a phase difference of 30 degrees. Is. Further, in the motor of this structure constituted by two rows, since the left and right are magnetically independent, a nonmagnetic member (not shown) such as a space portion or a connecting portion is provided between the boundary between the magnets 3a and 3b and the stator magnetic pole. ) Can be arranged. Further, when the period of the cogging torque is not 60 degrees in electrical angle, it is possible to cope with the phase of the permanent magnet being shifted by 1/2 of the electrical phase of the cogging torque generated on one side.

  Next, since the conventional stator magnetic poles are configured without gaps, the magnetic pole position sensor could not be arranged in the gaps between the respective phase magnetic poles. Therefore, magnets dedicated to the sensors were arranged in the axial direction. For this reason, there is a problem that the axial length becomes long. In this embodiment, therefore, a magnetic pole position sensor 6 is provided in the gap between the stator magnetic poles 4U and 4W as shown in FIG. Since the magnetic pole position sensor 6 has an electrical phase difference between the magnets of the rotor, two magnetic pole position sensors 6 are arranged for each magnet. For the permanent magnet 3a, the magnetic pole position sensors correspond to 6Ua, 6Va and 6Wa, and for the permanent magnet 3b, 6Ub, 6Vb and 6Wb respectively operate as a three-phase position detector. is there. In the drawing, the magnetic pole position sensor 6 is shown as an independent figure. However, since it is important that each sensor is arranged with a phase difference of 120 degrees in electrical angle, three sensors are integrally formed of resin. You may do it. Further, six magnetic pole position sensors arranged in two rows may be combined as one component. Thus, according to this embodiment, there is an effect that it is possible to provide a rotating electrical machine having a shorter axial length than a conventional rotating electrical machine even if a magnetic pole position sensor is arranged.

  Next, signal processing of the magnetic pole position sensor shown in FIG. 7 will be described with reference to FIG. FIG. 8 shows each signal of the magnetic pole position sensor described above as a time chart. The group of magnetic pole position sensors 6Ua, 6Va, and 6Wa is a Hall sensor 1 signal, and the Hall sensor 2 signal is three signals of 6Ub, 6Vb, and 6Wb. There are optical and magnetic types of magnetic pole position sensors, but in the present invention, a Hall sensor that operates with a magnetic field is employed in order to use the magnetic flux of the rotor magnet. Since the Hall sensor outputs an AC output signal at the N and S poles of the magnetic field, a signal is output as shown in the chart of FIG. 8 as the rotor rotates. Since the magnitude of the AC voltage signal is determined by the distance between the sensor and the magnet, the sensor for each phase needs to be attached at a certain gap. The six Hall sensor signals for each magnet generate an AC voltage with a phase difference of 30 degrees corresponding to the magnetized phase of the magnet. In order to drive as a motor, since there is only one inverter, it cannot be processed even if there are two signals of the magnetic pole position sensor. Therefore, in the present invention, the U-phase signal of the Hall sensor 1 Thus, a three-phase magnetic pole position sensor signal can be obtained with the phase of the center of the two signals that are shifted by 30 degrees in electrical angle. The composite signal of FIG. 8 is obtained by adding the in-phase signals of the hall sensor 1 and the hall sensor 2 respectively. Further, if the digital signal is converted at the zero cross point of the AC voltage by the comparator, the U-phase signal, V-phase signal, and W-phase signal shown in FIG. 8 can be produced. In this way, by using two sets of magnetic pole position sensors and adding the respective signals to create a three-phase signal, it is possible to reduce mounting errors that occur in one set of magnetic pole position sensors. Thereby, good control becomes possible. In particular, when the number of poles is large as in the present case, the mechanical attachment error becomes large at an electrical angle, which is a good means for reducing the attachment error.

  FIG. 9 is a diagram for explaining a second embodiment of the present invention. In the description so far, the permanent magnets 3 of the rotor are configured in two rows, but in this embodiment, the permanent magnets are one row of ring magnets. Therefore, a skew corresponding to the electrical angle is repeatedly provided for the cogging torque. When the cogging torque is the sixth-order component of the fundamental wave, it is generated with a period of 60 degrees in electrical angle, so the magnetization pitch of the permanent magnet is magnetized by shifting by 60 degrees in electrical angle.

  In this way, the combined waveform of the cogging torque from the end to the end of the magnet in the motor axis direction is successfully canceled out. In the present invention, a ring magnet is used as the permanent magnet to be used. Further, a similar effect can be obtained even in a structure in which a permanent magnet is embedded by making a hole in the rotor yoke 2. Here, the skew means that the magnetic poles of the permanent magnet are obliquely magnetized or arranged as shown in FIG.

  Further, a magnetic pole position sensor 6 provided in the gap between the stator magnetic poles 4Ua and 4Wa is shown in FIG. In this case, since the two sets of magnetic pole position sensors as described above are not necessary, the magnetic pole position can be detected by arranging one set of sensors for each phase in the central portion of the permanent magnet 3. Also in this case, the gap between the magnetic poles of each phase is a place where it is difficult to receive the magnetic flux fluctuation due to the magnetic pole current, and the magnetic flux of the permanent magnet 3 of the rotor can be detected without disturbance.

Next, a third embodiment will be described with reference to FIGS. In FIG. 11, the permanent magnets are configured in two rows, and the phases of the respective magnets are the same. Regarding the configuration of each part, the same reference numerals as those described above indicate the same parts, and detailed description thereof will be omitted. In this case, since it is arranged in two rows, it is possible to provide a magnetic insulating plate for preventing leakage of nonmagnetic material at the center of the shaft. If not provided, the magnets may be composed of one magnet because the magnets are in phase. In order to cancel the cogging torque as described above with such a structure, since the permanent magnet is in phase, it is realized by providing a phase difference between the stator magnetic poles. The figure is shown in FIG. FIG. 12 shows the magnetic pole teeth 4Ua1 and 4Ub1 of the stator magnetic poles 4Ua and 4Ub having a phase difference of 30 degrees in terms of electrical angle. Furthermore, the magnetic pole end face portions 10a, 10b, 11a,
11b becomes the same surface. When the above-described FIG. 5A is simply shifted, there is a drawback that a step is generated on the magnetic pole end face portion and the shape of the connecting portion connecting the phase magnetic poles becomes complicated. Therefore, in this embodiment, the shapes of the magnetic pole end faces are matched regardless of the phase difference of the magnetic pole teeth. Thus, the man-hours for assembly can be reduced by simplifying the shape of the magnetic pole end face.

  In this case as well, the permanent magnet 3 is in-phase magnetized as shown in FIG. 13, so that the magnetic pole position sensor 6 can be composed of one set of three.

  The magnetic pole shape shown in FIG. 2 is realized by pressing magnetic powder (compression molding), but it can be made by bending an iron plate or using magnetic materials. It is also possible to produce with a sintered material. Furthermore, it is also possible to realize a structure in which magnetic pole teeth made in a ring shape are combined by cutting in a necessary number.

  FIG. 14 shows the actual cogging torque calculated in the shape shown in FIG. The horizontal axis is the rotation angle, the waveform shown by the dotted line is the value when there is no phase difference in the permanent magnets, and the solid line is the value when the phase difference of 30 degrees in electrical angle is provided for the permanent magnets arranged in two rows. As can be seen from the graph, it can be reduced to about 1/5. Ideally, it may be even smaller, but in reality it is thought that this result was due to the influence of leakage magnetic flux between the magnet and the magnetic pole. Further, as described above, it is considered that the cogging torque can be further reduced by providing a non-magnetic magnetic insulation effect between the permanent magnets arranged in two rows and the magnetic poles.

  In the above description, the arrangement of the stator magnetic poles has been described by taking a three-phase motor as an example. In the description, the three magnetic poles of the U, V, and W phases are arranged on the entire circumference of the rotor. However, in the case of the three phases, the magnetic poles may be divided into integer multiples of 3, such as 6, 9, and 12 divisions. That is, it may be divided into an integral multiple of the number of motor phases.

  Furthermore, various motor structures can be configured by connecting the respective phase coils in series or in parallel. In addition, when the number of three phases is an even number or more, the same pole is mechanically arranged at a phase of 180 degrees, so that there is an effect that the attractive force acting between the stator magnetic pole and the rotor can be reduced. Noise can be reduced.

  In the present embodiment, the inner rotating type rotating electric machine has been described. However, an outer rotating type rotating electric machine may be used, and the same effect can be obtained. Furthermore, the rotating electrical machine of the present invention is considered to be a kind of claw pole type motor.

The motor structure perspective view of the 1st example of the present invention. The component figure which showed the components which comprise the stator magnetic pole of this invention. The division figure of the stator magnetic pole of this invention. The perspective view for the stator magnetic pole 1 phase of this invention. The perspective view for the stator magnetic pole 1 phase of this invention. Explanatory drawing of the motor of the 1st Example of this invention. Explanatory drawing which has arrange | positioned the magnetic pole position sensor to the motor of the 1st Example of this invention. The waveform processing timing chart of the magnetic pole position sensor of this invention. The perspective view of the 2nd Example of this invention. Explanatory drawing which has arrange | positioned the magnetic pole position sensor to the motor of the 2nd Example of this invention. The perspective view of the 3rd Example of this invention. The perspective view of the 3rd Example of this invention. Explanatory drawing which has arrange | positioned the magnetic pole position sensor to the motor of the 3rd Example of this invention. The graph explaining the effect of the 1st Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 2 Rotor yoke 3 Permanent magnet 4 Stator magnetic pole 5 Coil 7 Notch part 8 Cut-out part 10 Magnetic pole end surface 100 Rotor 200 Stator

Claims (20)

A rotor having a plurality of magnetic poles of permanent magnets on the outer peripheral surface;
Consists of multi-phase stator poles and stator windings,
Place multiple-phase stator poles in the circumferential direction,
Each phase is wound around a stator pole composed of two rows of stator windings as the center in the circumferential direction,
A rotating electric machine having a stator in which the stator poles of the plurality of phases are magnetically divided and having a magnetic pole position sensor between the divided stator magnetic poles . In claim 1,
The rotating electric machine characterized in that the stator magnetic pole is made of magnetic powder. In claim 1,
The rotating electric machine characterized in that the plurality of phases are three phases. In claim 1,
The rotating electric machine is characterized in that the stator magnetic pole is divided into an integral multiple of the number of motor phases. In claim 1,
The rotating electric machine, wherein the magnetic pole is produced by magnetization. In claim 1,
The rotating electric machine is characterized in that the magnetic pole is produced by embedding a magnetized permanent magnet. A rotor having a plurality of magnetic poles of permanent magnets on the outer circumferential surface arranged in two rows;
It consists of a stator pole and a stator winding,
Place multiple-phase stator poles in the circumferential direction,
Each phase is wound around a stator pole composed of two rows of stator windings as the center in the circumferential direction,
In addition, the rotating electric machine has a stator in which the stator poles of the plurality of phases are magnetically divided, and the permanent magnets arranged in the two rows have a phase difference in electrical angle. A rotating electrical machine that is characterized. In claim 7,
The rotating electrical machine according to claim 1, wherein the phase difference is 30 degrees in electrical angle. In claim 7,
The rotating electric machine characterized in that the stator magnetic pole is made of magnetic powder. In claim 7,
The rotating electric machine characterized in that the plurality of phases are three phases. In claim 7,
The rotating electric machine is characterized in that the stator magnetic pole is divided into an integral multiple of the number of motor phases. In claim 7,
The rotating electric machine, wherein the magnetic pole is produced by magnetization. In claim 7,
The rotating electric machine is characterized in that the magnetic pole is produced by embedding a magnetized permanent magnet. A rotor having a plurality of magnetic poles of permanent magnets on the outer peripheral surface;
It consists of a stator pole and a stator winding,
Place multiple-phase stator poles in the circumferential direction,
Each phase is wound around a stator pole composed of two rows of stator windings as the center in the circumferential direction,
And a rotating electric machine having a stator in which the magnetic poles of the plurality of phases are magnetically divided, wherein the magnets of the rotor are arranged with a skew. . In claim 14,
The rotating electrical machine characterized in that the skew has a phase difference of 60 degrees in electrical angle. The rotating electric machine according to claim 14, wherein the stator magnetic pole is made of magnetic powder. In claim 14,
The rotating electric machine characterized in that the plurality of phases are three phases. In claim 14,
The rotating electric machine is characterized in that the stator magnetic pole is divided into an integral multiple of the number of motor phases. In claim 14,
The rotating electric machine, wherein the magnetic pole is produced by magnetization. In claim 14,
The rotating electric machine is characterized in that the magnetic pole is produced by embedding a magnetized permanent magnet.

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