JPH0759310A - Hybrid type synchronous motor - Google Patents

Abstract

PURPOSE:To utilize effectively a reluctance torque in a permanent magnet motor and to make the design of the motor more free. CONSTITUTION:In a hybrid type synchronous motor, a rotor 28 is partitioned into a permanent magnet motor part 30 and a reluctance motor part 32. The partition into the permanent magnet motor part 30 and the reluctance motor part 32 is performed in the direction of a shaft 100 of the rotor 28, and both the motor parts are rotated in a body by sharing of a non-magnetic body 34. On a stator 44 a non-magnetic body 50 is provided, and thereby, the permanent magnet motor part 30 and the reluctance motor part 32 are prevented from being coupled to each other in a magnetic-circuit-wise. The permanent magnet motor part 30 and the reluctance motor part 32 can be designed independently of each other. The salient pole part formed on a magnetic body 40 of the reluctance motor part 32 is provided in the position shifted around the shaft 100 from the part for a permanent magnet 38 to be provided. When this angle is made 90 degrees, the pulsation of torque of the hybrid type synchronous motor is reduced, and when made 45 degrees, the maximum torque control of the motor is made easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor having a permanent magnet as a field, and more particularly to a motor having a permanent magnet arranged on the field and having a salient pole.

[0002]

2. Description of the Related Art As a drive motor for an electric vehicle, in addition to an induction motor, a synchronous motor using a permanent magnet as a field, that is, a permanent magnet motor can be used.
Since the permanent magnet motor is a motor having a large field magnetomotive force and a small size and light weight as compared with an induction motor, it is suitable for being mounted on an electric vehicle or the like.

FIG. 8 shows an example of a motor control circuit. The control circuit shown in this figure is based on the battery 10
The DC power supplied from the converter is converted into three-phase AC power by the inverter 12 and supplied to the motor 14. The current supplied from the inverter 12 to the motor 14 is vector-controlled by the controller 18 based on the rotation speed N of the motor 14 detected by the rotation speed sensor 16 according to the operation of the accelerator pedal, the brake pedal, etc. of the vehicle operator. To be done. The controller 18 performs this control by supplying a pulse width modulation (PWM) signal to the inverter 12.

FIG. 9 is a vector diagram when a permanent magnet motor is used as the motor 14. In this figure, the terminal voltage of the motor 14 is V and the motor current is I.
, The main magnetic flux from the permanent magnet is indicated by φ. The voltage induced in the coil of the motor 14 by this main magnetic flux φ is indicated by ωφ, and the terminal voltage V of the motor 14 has a value obtained by vector-adding the back electromotive force ωLI to this induced voltage ωφ. Where ω is the angular frequency,
L is the inductance of the motor 14. Therefore, a phase difference ψ occurs between the terminal voltage V and the motor current I.

Here, as the motor current I increases, the counter electromotive force ωLI increases, so that the terminal voltage V increases and exceeds the power supply voltage (voltage of the battery 10) at a certain point. Therefore, when the permanent magnet motor is used as the motor 14 in FIG. 8, so-called field weakening control is executed at a predetermined rotation speed or higher. This field weakening control is control executed by the controller 18 as vector control of the inverter 12, and the vector diagram in that case is as shown in FIG. 10, for example.

As shown in this figure, in the field weakening control, the motor current I is the horizontal axis current Iq and the straight axis current I.
It is treated as each component of d, and control is performed for each component.
The horizontal axis current Iq acts on the main magnetic flux φ interlinking the coil,
Generate torque. The direct-axis current Id is a current having a phase orthogonal to the horizontal-axis current Iq. This current Id
, The counter electromotive voltage represented by ωLdId in the figure is generated, and therefore, an effect equivalent to the weakening of the field by the permanent magnet is produced, and the value of the motor current I is the same. However, the terminal voltage V is suppressed as compared with the case of FIG. In the figure, Lq is the horizontal axis inductance, Ld is the direct axis inductance, and ωLqIq corresponds to ωLI in FIG. 9.

On the other hand, as a method of increasing the torque of the motor 14, for example, as described in Japanese Utility Model Publication No. 62-88463, the reluctance torque generated by the difference between the direct-axis inductance Ld and the horizontal-axis inductance Lq is effectively utilized. There is a method to do. 11 (a)-(c),
The structure of the rotor in the permanent magnet motor disclosed in this prior art is shown.

Each of the rotor structures shown in these figures is an inner rotor structure, and includes a yoke 20 formed of a magnetic material and a permanent magnet 22 arranged on the surface of the yoke 20 at a predetermined electrical angle from each other. Have Each of the rotor structures shown in these figures has a four-pole structure, and four permanent magnets 22 are provided. Also, the yoke 20
Is the salient pole portion 2 at an intermediate position between the adjacent permanent magnets 22, that is, a position corresponding to an intermediate electrical angle between the permanent magnets 22.
Have four. The salient pole portion 24 is provided as a corner portion of the yoke 20 in the first conventional example shown in FIG. 11A, and is provided in the second conventional example shown in FIG. 11B. It is provided as a protrusion protruding from the portion. Furthermore, in the third conventional example shown in FIG. 11C, it is provided as a separate magnetic body attached to the corner portion of the yoke 20.

In each of these rotor structures, the reluctance torque is effectively utilized in addition to the torque generated by the main magnetic flux φ. In other words, generally, the torque relating to the permanent magnet 22 given by φ · iq and the reluctance torque given by (Ld−Lq) · id · iq are both generated, so that the torque can be effectively utilized.

[0010]

However, in the conventional motor having such a configuration, since the permanent magnet and the salient pole portion are provided in the same magnetic circuit, interference between the two occurs, The degree of freedom in design was suppressed. Further, when the conventional rotor structure as shown in the drawing is rotated about the shaft 26, the gap between the rotor and the stator (not shown) provided around the rotor becomes a permanent magnet 22 and a salient pole portion 24.
There is a problem that so-called torque pulsation is likely to occur because of a sudden change between the two.

The present invention has been made to solve the above problems, and the degree of freedom in design is improved by separating the magnetic circuit related to the permanent magnet and the magnetic circuit related to the salient pole portion. It is an object of the present invention to improve torque and reduce torque pulsation. Another object of the present invention is to make it possible to suitably increase the reluctance torque despite the limitation of the gap between the armature and the field. An object of the present invention is to increase the maximum output torque of the motor and to easily execute the maximum torque control.

[0012]

In order to achieve such an object, the hybrid type synchronous motor of the present invention has a field magnet with a predetermined number of permanent magnets arranged at a predetermined electrical angle around the axis of the motor. A permanent magnet motor portion, and a permanent magnet motor portion and a reluctance motor portion that is divided along the axial direction of the motor and has a predetermined number of salient pole portions that are arranged at a predetermined electrical angle around the motor axis. The armature has a non-magnetic member for preventing the formation of a magnetic path in the motor axial direction extending between the permanent magnet motor portion and the reluctance motor portion, and the permanent magnet and the salient pole portion are mutually predetermined around the motor shaft. It is characterized in that it is arranged at a position deviated from the electrical angle.

Further, in the hybrid synchronous motor of the present invention, the salient pole portion is a protrusion of a magnetic material formed on the surface of the reluctance motor portion so as to be spaced from the armature, and is made of a material having a lower magnetic permeability than the protrusion. And a magnetoresistive member formed inside.

[0014]

In the hybrid synchronous motor of the present invention, the field is divided into a permanent magnet motor portion and a reluctance motor portion along the axial direction of the motor. In the permanent magnet motor portion, a predetermined number of permanent magnets are arranged around the motor axis at a predetermined electrical angle, and the permanent magnet motor portion generates a torque determined by the product of the horizontal axis current and the main magnetic flux. In addition, a predetermined number of salient pole portions are formed in the reluctance motor portion so as to be separated by a predetermined electrical angle when viewed around the axis of the motor. The reluctance motor portion generates a reluctance torque determined according to the difference between the horizontal axis inductance and the direct axis inductance.

In the present invention, such a permanent magnet motor portion and a reluctance motor portion are magnetically separated. That is, the formation of a magnetic path in the motor axial direction extending between the permanent magnet motor portion and the reluctance motor portion is prevented by the non-magnetic member provided on the stator. Therefore, in the present invention, both the permanent magnet torque and the reluctance torque can be used together under the same control condition, and the magnetic paths and shapes of the permanent magnet and the salient pole portion do not interfere with each other, so that the shapes of both can be optimized. It is possible to achieve a high output and reduce torque pulsation.

Further, the reluctance torque increases as the difference between the direct axis inductance and the horizontal axis inductance increases. When the protrusion of the magnetic material formed on the surface of the reluctance motor portion so as to be spaced from the armature is used as the salient pole portion, the direct-axis inductance is determined by the distance between the protrusion-free portion on the reluctance motor portion surface and the armature, The horizontal axis inductance is determined by the distance between the protrusion and the armature. In the present invention, a magnetoresistive member is provided inside the protrusion. The magnetoresistive member is formed of a material having a lower magnetic permeability than the protrusion, and functions as a magnetic resistance in the magnetic path that defines the direct-axis inductance. Therefore, even if the difference between the gap between the armature and the protrusion and the gap between the armature and the non-projection formation part is limited in the structural design, the direct-axis inductance and the horizontal-axis inductance are set by setting the magnetoresistive member. It is possible to increase the difference between. This increases the reluctance torque.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The same components as those in the conventional example shown in FIGS. 8 to 11 are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 shows a cross section in the motor axial direction of a hybrid synchronous motor according to an embodiment of the present invention. Further, FIG. 2 shows an AA cross section, and FIG. 3 shows a BB cross section.

As shown in these figures, in the present embodiment, the rotor 28 comprises a permanent magnet motor portion 30 and a reluctance motor portion 32. The permanent magnet motor portion 30 and the reluctance motor portion 32 are sectioned along the shaft 100 of the rotor 28 and are integrated by a cylindrical non-magnetic body 34. That is, the permanent magnet motor portion 30 and the reluctance motor portion 32 are connected to the shaft 10
Rotates as a unit around 0.

The permanent magnet motor portion 30 includes a magnetic body 36 functioning as a yoke and a permanent magnet 3 functioning as a field.
It is composed of 8. The magnetic body 36 is made of carbon steel, electromagnetic steel sheet, or the like, and the permanent magnet 38 is disposed on the surface of the magnetic body 36. When the motor of this embodiment is configured as a four-pole motor, four permanent magnets 38 are provided as shown in FIG. Permanent magnets 38 adjacent to each other
Are arranged around the axis 100 of the rotor 28 at positions shifted by 180 ° in electrical angle. Hereinafter, the line indicating the arrangement electrical angle of the permanent magnet 38 (the line connecting the center of the permanent magnet 38 and the shaft 100) is referred to as the magnetic pole shaft 102.

The reluctance motor portion 32 has a magnetic body 40 as shown in FIG. The magnetic body 40 is also made of the same material as the magnetic body 36, and has salient pole portions 42 as shown in FIG. When the present embodiment is configured as a 4-pole motor, four salient pole portions 42 are provided as shown in FIG. Salient pole 42
Around the axis 100 of the rotor 28,
It is arranged at a position deviated from the electrical angle by 90 °. Hereinafter, a line connecting the salient pole portion 42 and the shaft 100 will be referred to as a salient pole shaft 104.

The stator 44 includes a rotor 28 and a gap 46.
Are opposite to each other. The stator 44 has a coil 48 passed through a slot formed inside thereof. Further, the stator 44 has a non-magnetic body 50.

The non-magnetic member 50 is provided at an intermediate position between the portion of the stator 44 facing the permanent magnet motor portion 30 and the portion of the stator 44 facing the reluctance motor portion 32. The non-magnetic body 50 is made of stainless steel, aluminum, copper or the like, and has a shaft 1 of the rotor 28.
Magnetic path along the 00 direction, that is, the permanent magnet motor portion 3
0 and the reluctance motor portion 32 are cut off from a magnetic path, which is formed by making the relevant portion of the stator 44 non-magnetic. Further, for the same purpose, a gap 52 is provided between the magnetic body 36 and the permanent magnet 38 and the magnetic body 40.
Is provided. The gap 52 may be replaced by fitting a non-magnetic material. Due to the non-magnetic body 50 and the gap portion 52, the permanent magnet motor portion 30 and the reluctance motor portion 32 form different magnetic circuits from each other. As a result, in designing the embodiment shown in FIG. 1, under the same control conditions of current amplitude and phase,
Permanent magnet motor part 30 and reluctance motor part 32
Can be designed individually. That is, since there is almost no interference between the permanent magnet motor portion 30 and the reluctance motor portion 32, such a design work becomes possible, and a design with a higher degree of freedom becomes possible. The stator 44 is divided into two parts by the non-magnetic material 50, but the coil 48 is common to both parts.

Further, in this embodiment, since the permanent magnet motor portion 30 and the reluctance motor portion 32 are integrally formed, the torque φ · iq generated by the permanent magnet motor portion 30 and the torque () relating to the reluctance motor portion 32 ( Reluctance torque (Ld-Lq) * id * iq can be used together. That is, {φ + Ld
A torque of −Lq) · id} · iq can be obtained, and a large torque can be obtained as compared with a permanent magnet motor.

FIG. 4 shows the required current waveform in the permanent magnet motor portion 30. As shown in this figure, in the permanent magnet motor portion 30, the horizontal axis current i
As q, a current that advances by 90 electrical degrees in the rotation direction with respect to the N pole center position of the permanent magnet 38 is required.

FIG. 5 shows a method of adjusting the direct-axis inductance Ld and the horizontal-axis inductance Lq in this embodiment. This figure shows the relaxation motor portion 32.
3 is a partial cross section of FIG.

As shown in this figure, the gap g2 between the salient pole portion 42 and the stator 44 is smaller than the gap g1 at the portion other than the salient pole portion 42. The space g1 is a space that defines the direct-axis inductance Ld, and the space g2 is a space that defines the horizontal-axis inductance Lq. Therefore, by appropriately setting these intervals g1 and g2, the motor characteristics of the reluctance motor portion 32 can be optimally designed without affecting the characteristics of the permanent magnet motor portion 30.

Further, in this embodiment, since the volume of the permanent magnet 38 can be reduced as compared with the permanent magnet motor, a motor with a further reduced cost can be obtained. Further, since the reluctance torque is effectively used, the motor current I can be reduced as compared with the permanent magnet motor, and therefore the control device can be made smaller. In addition, since the permanent magnet 38 is provided on the surface of the rotor 28, the rotor 28 can be hollow, and the weight of the rotor 28 can be reduced while increasing its diameter. Further, the structure is relatively simple, so that the productivity is good. Since the salient pole shape can be freely designed as compared with the conventional case, it becomes extremely easy to form a so-called torque pulsation suppressing shape.

FIG. 6 shows a BB cross section of a hybrid type synchronous motor according to a second embodiment of the present invention, particularly a reluctance motor portion 32 thereof. The embodiment shown in this figure is characterized in that a non-magnetic material 54 is provided in a substantially central portion of the salient pole portion 42. The non-magnetic body 54 has the function of increasing the magnetic resistance of the magnetic path 108 without changing the magnetic resistance of the magnetic path 106. The magnetic path 106 is a magnetic path that determines the horizontal axis inductance Lq.
Is a magnetic path that defines the direct-axis inductance Ld. When the non-magnetic body 54 is provided on the magnetic path 108 in this manner, the magnetic path 10
Since the magnetic resistance related to No. 8 increases, the direct-axis inductance Ld increases.

The direct-axis inductance Ld and the horizontal-axis inductance Lq can be adjusted by the intervals g1 and g2 as described above, but this adjustment has a certain limit because it is limited by the structural design of the motor. There is. In the present embodiment, despite the existence of such a limit, the direct axis inductance Ld can be further increased. The increase in the direct-axis inductance Ld leads to an increase in the reluctance torque, so that a motor having a larger output torque than that of the first conventional example can be obtained. Further, the increase of the gap g1 may cause magnetic saturation, but such a problem does not occur in this embodiment.

FIG. 7 shows a BB cross section of the motor according to the third embodiment of the present invention, particularly the reluctance motor portion 32 thereof. As shown in this figure, in this embodiment, the salient pole shaft 104 is located at a position displaced from the magnetic pole shaft 102 by 45 electrical degrees in the rotational direction of the rotor 28.
That is, the salient pole portion 42 is provided at a position advanced by 45 electrical degrees in the rotation direction with respect to the permanent magnet 38.

By defining the salient pole shaft 104 in this way, it becomes possible to perform maximum torque control with a simpler algorithm. That is, the torque relating to the permanent magnet motor portion 30 is φ · iq, and the reluctance torque is (Ld−Lq) · id · iq, as described above.
Represented respectively. Therefore, the magnetic pole shaft 102 and the salient pole shaft 10
When the interval of 4 is an electrical angle of 90 degrees as in the first and second embodiments described above, the current phase angle that gives the maximum torque depends on the amplitude of the motor current I, so the maximum torque operation is performed. In the case of trying, it is necessary to change the current phase, that is, the value of the direct-axis current Id, according to the motor current I. On the other hand, when the salient pole shaft 104 is at a position advanced by 45 degrees with respect to the magnetic pole shaft 102 as viewed in the rotation direction of the rotor 28 as in the present embodiment, the permanent magnet motor portion 30 is provided.
The phase at which the torque generated at 1 reaches a peak matches the phase at which the torque generated by the reluctance motor portion 32 reaches a peak. Therefore, a complicated situation in which the phase at which the maximum torque is generated changes in accordance with the value of the current I does not occur, so that control that always makes the output of the motor the maximum value, that is, maximum torque control can be easily executed. Further, when the maximum torque control is performed, the torque related to the permanent magnet motor portion 30 is also changed to the reluctance motor portion 3.
Since the torque related to No. 2 has reached its peak, both torques can be used almost completely.

In the above description, the projection of the magnetic material is used as the means for giving the saliency, but other means can be adopted. Further, although the non-magnetic body 54 is used in the second embodiment, the non-magnetic body 54 only needs to have a function of increasing the magnetic resistance, and thus the air gap is the simplest. The non-magnetic material 54 in FIG. 6 is drawn with emphasis for convenience of illustration. Further, although the above description is directed to the inner rotor type motor structure, the present invention can be applied to the outer rotor type.

[0034]

As described above, according to the present invention,
The armature is made of a non-magnetic material that divides the field into a permanent magnet motor portion and a reluctance motor portion along the axial direction and prevents the formation of a magnetic path in the motor axial direction between the permanent magnet motor portion and the reluctance motor portion. The torque generated by the permanent magnet motor portion and the torque generated by the reluctance motor portion can be used together, so that a larger torque can be obtained as compared with, for example, a permanent magnet motor. Further, since the permanent magnet motor part and the reluctance motor part are separated on the magnetic circuit, it is possible to design both parts independently. For example, the permanent magnet and the salient pole part exist on the same magnetic circuit. The degree of freedom in design is significantly improved as compared with the case where the two interfere with each other.

Further, according to the present invention, since the magnetic resistance member formed of a material having a lower magnetic permeability than that of the protrusion is provided inside the protrusion of the magnetic body functioning as the salient pole portion, the direct-axis inductance and Even when the gap that defines the horizontal axis inductance, that is, the gap between the field and the armature is structurally constrained, the direct axis inductance can be increased appropriately, and the torque generated by the reluctance motor section is significantly increased. Can be increased to

[Brief description of drawings]

FIG. 1 is an axial sectional view showing a configuration of a hybrid type synchronous motor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA showing the configuration of a permanent magnet motor portion in this embodiment.

FIG. 3 is a BB cross-sectional view showing the configuration of the reluctance motor portion in the first embodiment.

FIG. 4 is a diagram showing a current waveform required in a permanent magnet motor portion.

FIG. 5 is a diagram showing a method of adjusting the direct-axis inductance and the horizontal-axis inductance in the first embodiment.

FIG. 6 is a cross-sectional view taken along line BB showing the structure of a hybrid synchronous motor according to a second embodiment of the present invention, particularly a reluctance motor portion thereof.

FIG. 7 is a cross-sectional view taken along line BB showing the configuration of a hybrid synchronous motor according to the third embodiment of the present invention, particularly the reluctance motor portion thereof.

FIG. 8 is a block diagram showing an example configuration of a control circuit for a synchronous motor.

FIG. 9 is a vector diagram of a permanent magnet motor.

FIG. 10 is a vector diagram when field weakening control is performed.

11A and 11B are diagrams showing a configuration of a synchronous motor according to a conventional example, where FIG. 11A is a first conventional example, FIG. 11B is a second conventional example, and FIG. It is a figure which shows the rotor structure of 3 prior art examples.

[Explanation of symbols]

 28 rotor 30 permanent magnet motor part 32 reluctance motor part 34, 50, 54 non-magnetic material 36, 40 magnetic material 38 permanent magnet 42 salient pole part 44 stator 46, 52 gap part 48 coil 100 rotor shaft 102 magnetic pole shaft 104 salient pole Axis 106, 108 Magnetic path g1, g2 Interval V Motor terminal voltage I Motor current Id Direct axis current Iq Horizontal axis current Ld Direct axis inductance Lq Horizontal axis inductance

Claims (2)

[Claims] 1. An armature having a coil, and a field magnet capable of rotating relative to the armature about a predetermined axis while being spaced from the armature, wherein the field magnet rotates about an axis of the motor. A permanent magnet motor portion having a predetermined number of permanent magnets arranged at a predetermined electrical angle, and a permanent magnet motor portion that is divided along the axial direction from the permanent magnet motor portion and a predetermined electric angle around the motor axis. A reluctance motor portion having a number of salient pole portions, and an armature having a non-magnetic member for preventing formation of a magnetic path in the motor axial direction between the permanent magnet motor portion and the reluctance motor portion, A hybrid synchronous motor characterized in that a magnet and a salient pole portion are arranged at positions deviated from each other by a predetermined electrical angle around the axis of the rotor. 2. The hybrid synchronous motor according to claim 1, wherein the salient pole portion is a protrusion of a magnetic body formed on the surface of the reluctance motor portion so as to be spaced from the armature, and a material having a lower magnetic permeability than the protrusion. And a magnetoresistive member formed inside the projection by the hybrid type synchronous motor.