JP2004129456A - Detector for rotor magnetic pole position of rotary-electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detector for the rotor magnetic pole position of a rotary-electric machine which is capable of detecting the rotor magnetic pole position with accuracy regardless of the state of operation. <P>SOLUTION: The detector for the rotor magnetic pole position of a rotary-electric machine comprises: a stator 2 with a coil wound in the circumferential direction; a rotor 3 which is placed inside the inner circumferential surface of the stator, coupled with a rotary shaft 3a, and rotatable relative to the stator 2 and has a plurality of magnets 3c; a non-magnetic plate 4 which is placed at an end face of the rotor 3 in the direction of the rotary shaft and prevents the magnetic flux of the magnets 3c from leaking in the direction of the rotary shaft; a magnetic flux guiding member 11 which penetrates the non-magnetic plate 4 and guides magnetic flux from the side of the non-magnetic plate 4 facing the rotor 3 to the opposite side; a magnetic material piece 10 which is magnetized by the magnetic flux guided by the magnetic flux guiding member 11; and a magnetic pole position detecting means 5 which senses the magnetic poles appearing on the magnetic material piece 10 and outputs a rotor magnetic pole position signal. The magnetic flux guiding member 11 is disposed closer to the stator 2 than the magnetic pole position detecting means 5. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotor magnetic pole position detecting device of a rotating electrical machine using a magnetic position sensor that outputs a rotor magnetic pole position signal in response to a magnetic pole appearing on a magnetic piece.
[0002]
[Prior art]
As a device for detecting the magnetic pole position of a rotor of a conventional rotary electric machine (motor (motor), generator (generator), generator / motor, etc.), there is, for example, one described in Patent Document 1. In this method, a magnetic piece is arranged on a non-magnetic end plate provided on an axial end face of a rotor, and the magnetic piece is magnetized by leakage magnetic flux of a magnet of the rotor. Then, the magnetic pole position of the rotor is detected by a magnetic position sensor which outputs a rotor magnetic pole position signal in response to the magnetic pole appearing on the magnetic piece.
[0003]
[Patent Document 1]
JP 2001-298932 A
[Problems to be solved by the invention]
However, in the above-described conventional rotor magnetic pole position detection device, when a relatively large current flows through the stator coil, such as during high-torque operation or high-output operation of the motor, the device is affected by the magnetic field from the stator. There is a possibility that the detection accuracy of the rotor magnetic pole position is reduced.
[0005]
The present invention has been made in view of such conventional problems, and has as its object to provide a rotor magnetic pole position detecting device of a rotating electrical machine that can accurately detect a rotor magnetic pole position regardless of an operation state. And
[0006]
[Means for Solving the Problems]
The present invention solves the above problem by the following means. Note that, for easy understanding, reference numerals corresponding to the embodiments of the present invention are given, but the present invention is not limited thereto.
[0007]
The present invention provides a stator (2) having a coil wound in a circumferential direction, a stator (2) disposed on the inner periphery of the stator, and connected to a rotating shaft (3a) to be rotatable relative to the stator (2). A rotor (3) having a plurality of magnets (3c); and a non-magnetic member disposed on an end face in the rotation axis direction of the rotor (3) for preventing magnetic flux of the magnet (3c) from leaking in the rotation axis direction. A body plate (4) and a magnetic flux guiding member that penetrates the non-magnetic plate (4) and guides the magnetic flux from the surface of the non-magnetic plate (4) facing the rotor (3) to the opposite side. (11), a magnetic piece (10) magnetized by the magnetic flux induced by the magnetic flux guiding member (11), and a rotor magnetic pole position signal is output in response to a magnetic pole appearing on the magnetic piece (10). A magnetic pole position detecting means (5); ) Is characterized in that said than pole position detecting means (5) is arranged close to the stator (2).
[0008]
[Action / Effect]
According to the present invention, since the magnetic flux guiding member is arranged close to the stator, more magnetic flux can be guided to the magnetic piece, and the magnetic piece can be strongly magnetized. Detection accuracy can be improved.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings and the like.
[0010]
1 and 2 are general configuration diagrams showing a motor (permanent magnet type synchronous motor) to which the magnetic pole position detecting device of the present invention is applied. 1 shows a cross section taken along line II of FIG. 2, and FIG. 2 shows a cross section taken along line II-II of FIG.
[0011]
The motor M includes a case 1, a stator 2, and a rotor 3.
[0012]
The case 1 has a cylindrical member 1a and a side plate 1b.
[0013]
The cylindrical member 1a is a cylindrical member having both ends opened, and the stator 2 is disposed on the inner periphery thereof.
[0014]
The side plate 1b is a member for closing the openings at both ends in the axial direction of the cylindrical member 1a. The side plate 1b is attached to the cylindrical member 1a with bolts (not shown). The side plate 1b is provided with a bearing 6 that rotatably supports a rotation shaft 3a (described later) of the rotor 3.
[0015]
The stator 2 includes a stator core 2a formed by laminating many electromagnetic steel plates, and a stator coil 2b. The stator core 2a has a ring-shaped back core portion and a tooth portion projecting radially inward from the back core portion. The stator coil 2b is wound around the teeth portion in a concentrated manner. The twelve stator coils 2b wound around the twelve teeth on the entire circumference are divided into three groups (U, V, W), each group consisting of four coils. Alternating currents (U-phase current, V-phase current, W-phase current) having different phases are supplied. That is, this motor is driven by three-phase alternating current. The stator 2 is press-fitted and fixed inside the cylindrical member 1 a of the case 1.
[0016]
The rotor 3 is arranged inside the stator 2. The rotor 3 has a rotor rotating shaft 3a and a cylindrical rotor core 3b formed by laminating a number of electromagnetic steel sheets.
[0017]
Both ends of the rotating shaft 3a are supported by the side plate 1b via bearings 6, and are rotatable.
[0018]
A magnet insertion hole is formed in the rotor core 3b, and a permanent magnet 3c is inserted and fixed therein. The permanent magnets 3c are magnetized in the thickness direction (substantially radial direction of the rotor 3), and eight permanent magnets are arranged in the circumferential direction so that poles on the outer peripheral side of the rotor are alternately arranged. Therefore, this rotor 3 is a rotor having four pole pairs.
[0019]
End plates 4 are provided on both axial end surfaces of the rotor core 3b. The end plate 4 is a nonmagnetic plate that prevents the magnetic flux of the permanent magnet 3c from leaking in the axial direction, and for example, a stainless plate can be used. A magnetic piece 10 is fixed on the end plate 4. The magnetic body piece 10 is, for example, an iron piece. The magnetic material pieces 10 have the same number (eight) as the permanent magnets 3c, and are arranged at regular angular intervals on the same circumference. An induction pin 11 made of a magnetic material (for example, iron) is connected to each magnetic piece 10. The guide pin 11 penetrates the end plate 4 and reaches the axial end face of the rotor core 3b. The guide pin 11 is a magnetic flux guide member for guiding the leakage flux of the permanent magnet 3c to the magnetic piece 10. Since the leakage magnetic flux is efficiently guided to the magnetic piece 10 by the induction pin 11, the magnetic piece 10 is strongly magnetized. Here, the leakage magnetic flux means a magnetic flux that does not contribute to the rotation torque of the rotor 3 among the magnetic flux generated by the permanent magnet 3c. In other words, the magnetic flux that does not go in the direction of the stator coil 2b is the leakage magnetic flux. In the radial gap type motor (the motor in which the stator is arranged on the outer peripheral side or the inner peripheral side of the rotor) as in the present embodiment, the magnetic flux appearing on the axial end face of the rotor core 3b is the leakage magnetic flux.
[0020]
On the other hand, a magnetic pole position sensor 5 using a latch output type Hall IC sensor is attached to the side plate 1b constituting the case 1. The magnetic pole position sensor 5 is a magnetic pole position detecting unit that outputs a rotor magnetic pole position signal in response to a magnetic pole appearing on the magnetic piece 10. The magnetic pole position sensor 5 is composed of three sensors, a U-phase sensor 5u, a V-phase sensor 5v, and a W-phase sensor 5w. °). Each sensor outputs a high-level or low-level signal according to the polarity of the magnetic flux on the opposing magnetic piece 10.
[0021]
FIG. 3 is a diagram showing an output signal with respect to an electrical angle of each magnetic pole position sensor.
[0022]
The outputs of the three sensors (U-phase sensor 5u, V-phase sensor 5v, W-phase sensor 5w) change as shown in FIG. 3 according to the rotor magnetic pole position (rotor rotation phase). Therefore, the rotor magnetic pole position can be detected with a resolution of 60 electrical degrees from the combination of the three signals.
[0023]
Next, the detection accuracy of the magnetic pole position detection device will be described.
[0024]
FIG. 4 is a diagram showing details of the magnetic piece, and an enlarged view of the vicinity of the magnetic piece in FIG. 2 is shown.
[0025]
As shown in FIG. 4, in the present embodiment, the induction pin 11 and the magnetic pole are set so that R1 (the radius of the circumference where the induction pin 11 is disposed)> R2 (the radius of the circumference where the magnetic pole position sensor 5 is disposed). The position sensor 5 was arranged.
[0026]
This arrangement has the following effects.
[0027]
That is, the leakage magnetic flux appearing on the axial end face of the rotor core 3b is larger on the side closer to the stator 2 (rotor outer peripheral side). Therefore, when the guide pin 11 is provided closer to the stator 2, more magnetic flux can be guided to the magnetic piece 10, and the magnetic piece 10 can be strongly magnetized. Therefore, the detection accuracy can be improved by providing the guide pin 11 close to the stator 2.
[0028]
If the location of the magnetic pole position sensor 5 is close to the stator 2, the Hall IC of the magnetic pole position sensor 5 will be sensitive to the magnetic field generated by the stator 2. Therefore, as in the present embodiment, by moving the magnetic pole position sensor 5 as far away from the stator 2 as possible, the effect of the stator magnetic field can be reduced, and the detection accuracy can also be improved.
[0029]
Therefore, as described above, by setting R1> R2, the detection accuracy of the magnetic pole position detecting device can be improved.
[0030]
Further, when the magnetic piece 10 is formed to have a constant width such as a rectangle, for example, it has been confirmed by experiments by the inventors that the output of the magnetic pole position sensor 5 is affected by the stator magnetic field. Was. This is because the portion of the magnetic piece 10 near the stator 2 picks up the magnetic flux generated by the stator 2.
[0031]
Therefore, the width (W1) of the center portion of the magnetic piece 10 to which the guide pin 11 is attached is increased to enable the above-described R1> R2, and the width (W2) of the tip portion (both ends in the circumferential direction) is reduced. The size was reduced so that the magnetic piece 10 was kept away from the stator 2. In other words, the circumferential length α2 of the magnetic material piece 10 on the stator side (outer circumferential side) is shorter than the circumferential length α1 on the rotor rotation shaft side (inner circumferential side). By doing so, the influence of the stator magnetic field on the magnetic piece 10 can be reduced, and the detection accuracy of the magnetic pole position detecting device can be further improved.
[0032]
The effect of the stator magnetic field on the magnetic piece 10 can be reduced as the width of the magnetic piece 10 is reduced. However, if the width is too small, the output of the magnetic pole position sensor 5 when the rotor 3 vibrates in the radial direction is reduced. May become unstable. For this reason, it is desirable that the width W2 of the tip be sufficiently larger than the radial vibration width of the rotor 3 assumed during the operation of the motor.
[0033]
According to the present embodiment, by providing the guide pin 11, the leakage magnetic flux appearing on the axial end face of the rotor core 3b can be efficiently guided to the magnetic piece 10, so that the magnetic piece 10 can be strongly magnetized. Thus, the accuracy of detecting the magnetic pole position of the rotor can be improved.
[0034]
Further, by providing the induction pin 11 close to the stator 2, the magnetic body piece 10 can be more strongly magnetized, and the detection accuracy can be further improved.
[0035]
Further, by moving the magnetic pole position sensor 5 away from the stator 2, it is possible to reduce the influence of the stator magnetic field, thereby improving the detection accuracy.
[0036]
Further, since the circumferential length α2 of the magnetic piece 10 on the stator side is shorter than the circumferential length α1 of the rotor rotation shaft side, the influence of the stator magnetic field can be reduced, and the magnetic pole position can be reduced. The detection accuracy of the detection device could be further improved.
[0037]
Thus, even when a relatively large current flows through the stator coil, such as during high-torque operation and high-output operation of the motor, the influence of the stator magnetic field is suppressed, and the detection accuracy of the magnetic pole position detecting device is reduced. It became possible to improve.
[0038]
Without being limited to the embodiments described above, various modifications and changes can be made within the scope of the technical idea, and it is apparent that they are equivalent to the present invention.
[0039]
For example, in the above embodiment, a motor (motor) is described as an example of the rotating electric machine, but it goes without saying that a generator (generator) or a generator / motor may be used.
[0040]
Further, in the above-described embodiment, the type of motor in which the stator is disposed on the outer peripheral side of the rotor has been described as an example. Can be obtained.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing a motor to which a magnetic pole position detecting device according to the present invention is applied, and is a cross-sectional view seen from a direction orthogonal to a rotation axis.
FIG. 2 is an overall configuration diagram showing a motor to which the magnetic pole position detecting device of the present invention is applied, and is a cross-sectional view as viewed from a rotation axis direction.
FIG. 3 is a diagram showing an output signal with respect to an electrical angle of each magnetic pole position sensor.
FIG. 4 is a diagram showing details of a magnetic piece;
[Explanation of symbols]
M Motor 1 Case 2 Stator 3 Rotor 3a Rotating shaft 3b Rotor core 3c Permanent magnet 4 End plate (non-magnetic plate)
5 Magnetic pole position sensor (magnetic pole position detecting means)
5u U-phase sensor 5v V-phase sensor 5w W-phase sensor 10 Magnetic piece 11 Induction pin (magnetic flux induction member)

Claims (2)

A stator wound with coils in the circumferential direction;
A rotor arranged on the inner periphery of the stator, connected to a rotating shaft, rotatable relative to the stator, and having a plurality of magnets,
A non-magnetic plate disposed on the rotation axis direction end face of the rotor to prevent the magnetic flux of the magnet from leaking in the rotation axis direction;
A magnetic flux guide member that penetrates the non-magnetic plate and guides the magnetic flux from the side of the non-magnetic plate facing the rotor to the opposite side;
A magnetic piece magnetized by the magnetic flux induced by the magnetic flux guide member,
Magnetic pole position detecting means for outputting a rotor magnetic pole position signal in response to a magnetic pole appearing on the magnetic piece,
The magnetic flux guide member is disposed closer to the stator than the magnetic pole position detection means,
A rotor magnetic pole position detecting device for a rotating electric machine, characterized in that: 2. The rotor magnetic pole position of the rotating electric machine according to claim 1, wherein a length of a side of the magnetic body piece disposed at a short distance from the stator is shorter than a length of a side disposed at a long distance from the stator. 3. Detection device.

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