KR101911614B1 - Axially laminated synchronous reluctance motor for improving torque and power factor and design method thereof - Google Patents

Abstract

The present invention relates to an axial lamination synchronous reluctance motor for improving torque and power factor. A synchronous reluctance motor includes: a tooth radially protruding along a circumferential direction; a stator having a slot formed between adjacent teeth; A rotor having a round shape and accommodated in the receiving area and rotating; The rotor comprising: a shaft centrally positioned to rotate the rotor; A lamination surface formed in the center of a shaft hole into which the shaft can be inserted and forming a concave space between a plurality of blades extending to an end of the rotor and a fastener formed on the lamination surface toward the shaft hole A non-magnetic metal spider; A plurality of cores sequentially stacked in the axial direction on the laminated surface; An insulating sheet positioned between the lamination surface and the core and between the respective cores; A pole holder of insulating material which is laminated on the outermost core and forms an end of the rotor; A coupling member inserted from the pole holder to the coupling so as to couple the core, the insulation sheet, and the pole holder to the spider; .
According to such a configuration, it is possible to provide a synchronous reluctance motor in which the torque is large and the torque ripple is reduced, while having a new shape with good mechanical rigidity and no lip.

Description

Technical Field [0001] The present invention relates to an axial laminated synchronous reluctance motor for improving torque and power factor,

The present invention relates to an axial laminated synchronous reluctance motor for improving torque and power factor and a design method thereof.

Actuators are a vital element that is constantly in demand in the plant industry in a wide range of industries, including industrial equipment, construction, robots, shipbuilding, automotive and aircraft. Previously, hydraulic and pneumatic type actuators have been mainly used as driving power sources for actuators. Recently, electric type actuators which are simple to install and easy to control and manage are widely used.

An induction motor is mainly used as a driving source of an electric actuator, but in recent years, the use of a synchronous reluctance motor (SynRM) has been increasing.

Synchronous reluctance motors have not been widely used due to their low efficiency and low output characteristics. Recently, they have been attracting much attention due to the development of power electronic devices and circuit technologies and their disadvantages. Since the rotor of the synchronous reluctance motor has a simple structure without a winding, it is suitable for a place where the operation is required for a long time because the trouble is small and reliability is high, and maintenance is easy.

A synchronous reluctance motor is a motor that uses a principle in which a rotational force is generated by a change in magnetoresistance due to rotation of a rotor. When the rotor is started, the flow of the magnetic flux is blocked by the magnetic flux barrier, and the magnetoresistance between the magnetic flux barrier side (i.e., the q-axis) and the respective magnetic flux barrier groups (i.e., the d-axis) Reluctance torque is generated by the difference in magnetoresistance. Since the reluctance torque is synchronized with the magnetic flux of the stator, the rotor is rotated at the synchronous speed by the reluctance torque.

1 is a diagram showing a conventional segment type synchronous reluctance motor.

The segment type synchronous reluctance motor has an open magnetic flux barrier, and is easy to manufacture and has an advantage in mass production. The segmented rotor includes a core in which a plurality of steel sheet sheets are laminated, wherein several magnetic flux barriers are formed.

Since a large amount of leakage magnetic flux is generated through the rib formed at the end of the magnetic flux barrier, it is preferable to make the width of the rib as small as possible to reduce the leakage magnetic flux. In addition, the lip is a part having weak mechanical rigidity and there is a risk of breakage during prolonged use.

Therefore, a new type of synchronous reluctance motor with good mechanical rigidity and no rib is required.

Korean Patent No. 10-0437189

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a synchronous reluctance motor having a high torque and a reduced torque ripple, .

According to an aspect of the present invention, there is provided a synchronous reluctance motor including: a stator having radially projected teeth along a circumferential direction, a stator having slots formed between adjacent teeth, A rotor having a round shape and accommodated in the receiving area and rotating; The rotor comprising: a shaft centrally positioned to rotate the rotor; A lamination surface formed in the center of a shaft hole into which the shaft can be inserted and forming a concave space between a plurality of blades extending to an end of the rotor and a fastener formed on the lamination surface toward the shaft hole A non-magnetic metal spider; A plurality of cores sequentially stacked in the axial direction on the laminated surface; An insulating sheet positioned between the lamination surface and the core and between the respective cores; A pole holder of insulating material which is laminated on the outermost core and forms an end of the rotor; A coupling member inserted from the pole holder to the coupling so as to couple the core, the insulation sheet, and the pole holder to the spider; .

In addition, the number of the teeth is 24, the coils are wound in a linear distribution shape on the teeth, and the four wings are spaced apart by the same interval.

The number of the cores and the number of the insulating sheets is three.

Also, the output of the synchronous reluctance motor is 340 W, and the slot width in the stator is 1.5 to 2 mm.

In addition, each of the cores in the rotor has the same thickness, and the core has a thickness of 3.0 to 3.5 mm.

Further, each of the insulating sheets in the rotor has the same thickness, and the thickness of the insulating sheet is 1.0 to 1.5 mm.

The thickness of the pole holder is 2.5 to 3.5 mm.

Further, the slot width is 2.0 mm, the core thickness is 3.25 mm, the thickness of the insulating sheet is 1.25 mm, and the thickness of the pole holder is 3.0 mm.

In the method of designing a synchronous reluctance motor according to another embodiment of the present invention, the motor includes a tooth radially protruding in a circumferential direction, a stator having a slot formed between adjacent teeth, A spider having a rotor accommodated in the receiving area and rotating, the rotor having a blade and a laminated surface around a shaft hole formed at the center; A plurality of cores sequentially stacked in the axial direction on the laminated surface; An insulating sheet positioned between the lamination surface and the core and between the respective cores; A pole holder of insulating material which is laminated on the outermost core and forms an end of the rotor; A coupling member inserted from the pole holder to the coupling so as to couple the core, the insulation sheet, and the pole holder to the spider; Initializing a CAD file for designing the stator and the rotor; Modeling the design data for a finite element analysis using the slot width of the rotor, the thickness of the core, the thickness of the insulating sheet, and the thickness of the pole holder as design variables; Setting a range of the design parameter using a Box-Bencken method, which is one of reaction surface methods, which is a statistical approximation method; Outputting torque and torque ripple values while varying the value of the design parameter using a finite element analysis program; .

According to the present invention, it is possible to provide a synchronous reluctance motor having a high torque and a reduced torque ripple while having a new shape with good mechanical rigidity and no lip, and a design method.

1 is a diagram showing a conventional segment type synchronous reluctance motor.
2 is a view showing a rotor of a synchronous reluctance motor without a rib according to an embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view taken along line AA 'in the synchronous reluctance motor of FIG. 2. FIG.
4 is a diagram showing design parameters for an optimum design in a 1/4 model of a synchronous reluctance motor according to an embodiment of the present invention.
5 is a graph showing torque characteristics according to a range of design parameters in a synchronous reluctance motor according to an embodiment of the present invention.
6 is a graph showing characteristics of torque ripple according to a range of design parameters in a synchronous reluctance motor according to an embodiment of the present invention.
7A is a diagram showing a magnetic flux density distribution in a conventional segment type synchronous reluctance motor.
7B is a diagram showing the magnetic flux density distribution in the axial stacked synchronous reluctance motor of the present invention.
8 is a graph comparing torque characteristics with time in a conventional synchronous reluctance motor of the present invention.
9 is a graph showing torque characteristics according to a current phase angle in the synchronous reluctance motor of the present invention.
10 is a photograph of a prototype manufactured for an experiment in a synchronous reluctance motor of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements throughout. The same reference numerals in the drawings denote like elements throughout the drawings.

2 is a view showing a rotor of a synchronous reluctance motor without a rib according to an embodiment of the present invention. 3 is a schematic cross-sectional view taken along the line A-A 'in the synchronous reluctance motor of FIG. 2; 4 is a diagram showing design parameters for an optimum design in a 1/4 model of a synchronous reluctance motor according to an embodiment of the present invention. 5 is a graph showing torque characteristics according to a range of design parameters in a synchronous reluctance motor according to an embodiment of the present invention. 6 is a graph showing characteristics of torque ripple according to a range of design parameters in a synchronous reluctance motor according to an embodiment of the present invention.

2 to 4, the synchronous reluctance motor (or motor) of the present invention includes a plurality of teeth 201 radially protruding in the circumferential direction, a plurality of teeth 201 formed between adjacent teeth 201, 202, a stator 200 having a receiving area at the center thereof, and a rotor 100 accommodated in the receiving area and rotating.

The stator 200 has the same structure as the induction motor. The motor of the present invention has 60 Hz, 3-phase, and 4-poles, while the stator 200 is wound in a linear distribution shape and has 24 slots.

The rotor 100 includes a shaft 110, a spider 120, an insulating sheet 130, a core 140, a pole holder 150 and a fastening member 160. The rotor 100 has a rounded shape.

The shaft 110 is located at the center of the rotor 100 and rotates the entire rotor 100 when power is transmitted.

The spider 120 is made of a non-magnetic metal, and a shaft hole for inserting the shaft 110 is formed in the center. The spider 120 has a plurality of blades 121 extending to the end of the rotor 100 and has a lamination surface 122 forming a concave space 123 between the blades 121 and the blades 121 . A fastening hole 124 is formed in the laminated surface 122 toward the shaft hole.

A plurality of cores 140 are stacked on the stacking surface 122 of the spider 120 in the axial direction. Here, the axial direction refers to the direction in which the shaft 110 is viewed.

The insulating sheet 130 is for forming a magnetic flux barrier and is located between the lamination surface 122 and the core 140 and between the respective cores 140. [

The pole holder 150 is formed of an insulating material and is laminated on the outermost core 140 to form an end portion of the rotor 100.

The fastening member 160 is inserted from the pole holder 150 to the fastener 124 so as to couple the core 140, the insulating sheet 130 and the pole holder 150 to the spider 120. For this purpose, the core 140, the insulating sheet 130, and the pole holder 150 may be formed with fastening holes for inserting the fastening members 160.

The rotor 100 having such a structure is advantageous in that it can have a lip-free shape and has excellent mechanical rigidity because the core 140 is laminated in the axial direction and fastened by the fastening member 160.

Referring to FIG. 4, a design parameter is set that can affect the torque characteristics for the optimum design in which the torque is large and the torque ripple is reduced in the motor of the present invention.

In the design of the rotor of the conventional synchronous reluctance motor, the factors of L _d and L _q are the magnetic flux barrier and the thickness of the rotor core. There are findings _w ratio K of the rotating rotor flux barrier of electron width and the width of the rotor core to generate a d-axis torque when sayi eseo 0.2 and 0.6 and q-axis inductance difference that the maximum value.

In the axial laminated synchronous reluctance motor of the present invention, the slot width indicating the width at which the slot 202 opens is selected as the design parameter of the stator 200, and the core 140 is selected as the design parameter of the rotor 100, The thickness of the pole holder 150 is selected in addition to the thickness of the insulating sheet 130 and the thickness of the pole holder 150. [ Here, each core 140 and the insulating sheet 130 have the same thickness. The thickness of the pole holder 150 is a design parameter for selecting the position of the core 140 in the entire rotor 100 and refers to the thickness of the thickest portion of the pole holder 150. [

In order to analyze the torque characteristics considering the magnetic saturation phenomena based on these design parameters, the range of the design parameters is set by using the Box-Benckens method, which is one of the reaction surface methods, The torque and torque ripple values are output while changing the value.

The response surface method uses a statistical analysis method for the response surface of a response of a system or a change in the output of an electric device by using a combination of several independent variables or design variables. It is a technique to make a model.

There are many experimental design methods in the reaction surface method. In the present invention, when confident that all factors are not at the same time low or high level, the Box-Behnken (Box- Benzene) method was used. The Box - Benkent method has fewer experiments than the Central Composite Design (CCD), one of the other reaction surface methods, when the number of factors is the same. The Box - VENGEN design is an experimental design that does not include the vertices' experimental points, and plans to experiment at the center of the hexahedron corners and at the center of the entire experimental area. It can be used advantageously if the experiment cost at the vertex is too much or is practically impossible.

In this experiment, the motor has 24 slots of 60Hz, 3 phases, 4 poles, distribution line, and the output is 340W. In addition, it was confirmed that the number of the core 140 and the number of the insulation sheets 130 is optimal through the optimum design using the box-Benchmark method.

Fig. 5 shows torque characteristics according to changes in core thickness, slot width, and insulating sheet thickness, and Fig. 6 shows torque ripple characteristics according to changes in core thickness, slot width, and insulating sheet thickness. For the performance of the electric motor, it is desirable to maximize the torque and minimize the torque ripple.

5 and 6, it was confirmed that the torque characteristics of the electric motor were excellent when the slot width was 1.5 to 2.0 mm, the core thickness was 3.0 to 3.5 mm, and the insulating sheet thickness was 1.0 to 1.5 mm. Also, the pole holder had a good torque characteristic at a thickness of 2.5 to 3.5 mm.

In order to find the design parameter value which shows the best torque characteristic, it is repeatedly experimented while changing the value of each design variable within the range of the design variable.

Table 1 shows torque and torque ripple due to changes in design parameters.

analysis Design variables (stator) Design variables (rotor) result Slot width Pole Holder Thickness Core thickness Insulation sheet thickness T [Nm] T.R [%] One 1.75 3.0 3.25 1.00 2.1736 0.7870 2 1.50 3.0 3.00 1.25 2.1515 0.9093 3 1.75 2.5 3.25 1.00 2.2582 0.1956 4 1.75 3.0 3.25 1.25 * * 5 1.50 3.0 3.50 1.25 * * 6 1.50 3.0 3.00 1.25 2.2944 0.2496 7 2.00 3.0 3.00 1.25 2.1949 0.2616 8 2.00 3.0 3.25 1.25 2.2895 0.1819 9 1.75 2.5 3.25 1.50 2.1921 0.5252 10 1.75 2.5 3.00 1.25 2.2856 0.2039 11 1.50 3.0 3.25 1.50 * * 12 2.00 3.0 3.25 1.50 * * 13 1.50 3.0 3.25 1.00 2.1891 0.2417 14 2.00 3.0 3.25 1.00 2.0980 0.2490 15 1.75 2.5 3.50 1.25 * * 16 1.75 3.5 3.00 1.25 2.1259 0.2656 17 1.75 3.0 3.25 1.25 * * 18 1.75 3.5 3.50 1.25 * * 19 1.75 3.0 3.00 1.50 * * 20 1.75 3.0 3.50 1.00 * * 21 1.50 3.5 3.25 1.25 * * 22 1.75 3.0 3.50 1.50 * * 23 1.75 3.0 3.00 1.00 2.2557 0.2964 24 1.75 3.0 3.25 1.50 * * 25 2.00 3.5 3.50 1.50 2.1752 0.4513

In the above iterative experiment, the torque was found to be 2.2895Nm at the 8th item and the torque ripple was the lowest at 18.19%, which was confirmed as the optimum design variable value. The value of each design variable was 2.0mm for the slot width, 3.0 mm, a core thickness of 3.25 mm, and an insulating sheet thickness of 1.25 mm.

In this way, the range of design parameters was selected in the design method using the Box-Bencken method in the reaction surface method, and the configuration of the synchronous reluctance motor in which the torque was high and the torque ripple was reduced was obtained through repeated experiments .

7A is a diagram showing a magnetic flux density distribution in a conventional segment type synchronous reluctance motor. 7B is a diagram showing the magnetic flux density distribution in the axial stacked synchronous reluctance motor of the present invention. This means that magnetic flux saturation occurs in the red color.

In the conventional segment type synchronous reluctance motor, saturation occurs partially at the lip portion and stator tooth portion, but it can be confirmed that there is no saturation portion in the axial laminated synchronous reluctance motor of the present invention.

8 is a graph comparing torque characteristics with time in a conventional synchronous reluctance motor of the present invention.

In the conventional segment type synchronous reluctance motor, the average torque was 1.9 Nm and the torque ripple was 7.75%. In the axial laminated synchronous reluctance motor of the present invention, the average torque was 2.2 Nm and the torque ripple was 18.19% . From these results, it can be seen that the torque ripple of the axial laminated synchronous reluctance motor of the present invention is low and the torque is increased.

9 is a graph showing torque characteristics according to a current phase angle in the synchronous reluctance motor of the present invention.

In order to analyze the torque characteristics, the current phase angle at which the maximum torque is generated is derived by changing the input current of the stator. As can be seen from the results of FIG. 9, it can be seen that the highest average torque is generated at a current phase angle of about 45 degrees, and the average torque at this time is about 2.2 Nm.

The d-axis and q-axis inductances were calculated by the 2D finite element method. In order to calculate the inductance, the peak peak current (Ia_peak) of the phase of the stator was input and the magnetic flux potential, which depends on the position of the rotor, was taken and the flux connected to the winding was calculated.

10 is a photograph of a prototype manufactured for an experiment in a synchronous reluctance motor of the present invention.

In order to verify the torque performance of the proposed motor according to the design parameters, prototypes were fabricated and tested. The experimental set consisted of dynamometer and torque sensor, power quality analyzer, power supply, and inverter for vector control.

The axial laminated synchronous reluctance motor of the present invention in which the ribs are not present can replace the induction motor for driving the electric actuators in the torque density and the efficiency portion per unit volume.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention will be.

100: rotor
110: Teeth
120: Slot
121: Wings
122:
123: Concave space
124: fastener
130: Insulation sheet
140: Core
150: pole holder
160: fastening member
200: stator
201: Teeth
202: Slot

Claims (9)

In a synchronous reluctance motor,
A stator having radially projected teeth along a circumferential direction, a stator having slots formed between adjacent teeth, and a receiving area at the center;
A rotor having a round shape and accommodated in the receiving area and rotating;
Lt; / RTI >
The rotor
A shaft centered to rotate the rotor;
A lamination surface formed in the center of a shaft hole into which the shaft can be inserted and forming a concave space between a plurality of blades extending to an end of the rotor and a fastener formed on the lamination surface toward the shaft hole A non-magnetic metal spider;
A plurality of cores sequentially stacked in the axial direction on the laminated surface;
An insulating sheet positioned between the lamination surface and the core and between the respective cores;
A pole holder of insulating material which is laminated on the outermost core and forms an end of the rotor;
A coupling member inserted from the pole holder to the coupling so as to couple the core, the insulation sheet, and the pole holder to the spider;
Lt; / RTI >
Wherein the synchronous reluctance motor has a slot width of the rotor, a thickness of the core, a thickness of the insulating sheet, and a thickness of the pole holder, in order to design a torque with a high torque and a reduced torque ripple in the stator and the rotor, Designed as a design variable, it is designed using the Box-Bencken method, which is one of the reaction surface methods, which is a statistical approximation method,
In the synchronous reluctance motor,
The number of teeth is 24,
A coil is wound on the teeth in a distributed linear form,
Wherein the four wings are spaced at equal intervals,
The number of the core and the insulating sheet is three,
The output of the synchronous reluctance motor is 340 W,
Each of said cores and said insulating sheet in said rotor has the same thickness,
Wherein the slot width is 2.0 mm, the core thickness is 3.25 mm, the thickness of the insulating sheet is 1.25 mm, and the thickness of the pole holder is 3.0 mm. delete delete delete delete delete delete delete delete

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