JP2001258220A - Reluctance motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve torque-slip characteristic in the case of induction start in a reluctance motor wherein a rotor has flux barrier slits convex toward the center of the rotor, and conductive material such as copper or a copper alloy and aluminum or an aluminum alloy is injected in the flux barrier slits. SOLUTION: In this reluctance motor, a layer whose slit length is the shortest in flux barriers is connected with some layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor utilizing reluctance torque, and more particularly to a reluctance motor which can easily start itself even when a load having a large resistance torque is connected with a commercial power supply.

[0002]

2. Description of the Related Art FIG. 4 is a plan view of a core sheet showing a configuration of a rotor core in a conventional reluctance motor. The rotor is formed by stacking magnetic core sheets 1. Reference numerals 2a to 2f denote flux barrier slits having a shape protruding toward the center of the rotor. A non-magnetic and conductive material such as copper or a copper alloy is injected into the flux barrier, and a non-magnetic conductive material is provided. Are connected by a non-magnetic conductive material in the form of a short-circuit ring provided at both axial ends of the rotor core. By injecting the non-magnetic conductive material into the flux barrier, a secondary conductor is formed like an induction machine, and the induction can be started with a commercial power supply.

[0003]

In the above-mentioned conventional reluctance motor, an imbalance exists in the secondary circuit as an induction machine due to the flux barrier slit on the rotor side. When starting by induction with a commercial power supply, a negative-phase current flows to the secondary side due to the imbalance of the secondary circuit. Due to this reverse-phase current, a negative torque is generated in a small slip region (low slip region), and this torque is superimposed on the positive-sequence torque. Is generated. At this time, there is a problem that the value of the minimum torque at this minimum point becomes equal to or less than the torque required for acceleration, and acceleration may not be possible.

[0004]

According to the reluctance motor of the present invention, a plurality of flux barrier slits having a shape protruding toward the center of the rotor are provided in a rotor core on which a magnetic core sheet is laminated. A non-magnetic conductive material is injected into the flux barrier slit to form a secondary conductor, wherein the flux barrier slit having the shortest slit length and some of the flux barrier slits are combined to form a combined flux. It is a barrier.

[0005] A radial rib is provided at the center of the combined flux barrier.

Further, a hollow region is provided in a rib provided in the combined flux barrier.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the drawings will be described below.

Embodiment 1. FIG. 1 is a plan view of a core sheet showing a configuration of a rotor core of a reluctance motor according to an embodiment of the present invention. The rotor is formed by laminating the core sheets 1. Reference numeral 4 denotes a flux barrier slit having the shortest slit length among the flux barrier slits and a next flux barrier slit (in the case of the core sheet of the conventional reluctance motor shown in FIG. 4, 2a, 2b
And a newly formed combined flux barrier. After the rotor core is formed, a non-magnetic conductive material such as copper, copper alloy, aluminum, or aluminum alloy is injected into the barrier slits including the coupling flux barrier 4 to form a short-circuit ring-shaped non-magnetic material at both axial ends of the rotor core. Joined with a conductive material to form a secondary conductor.

By doing so, the cross-sectional area of the newly formed combined flux barrier 4 becomes larger than the total sectional area of the two flux barriers 2a and 2b before combining. The electric resistivity of the conductive material injected into the flux barrier is represented by r, the equivalent length of the secondary conductor is represented by l, and the sectional area is represented by S.
Since the resistance R of the secondary conductor is represented by R = r * 1 / S, the resistance R _{4 of the} secondary conductor formed in the flux barrier ₄ is equal to the two flux barriers 2a before coupling. , 2b are smaller than the parallel resistance value. As the resistance value of the secondary conductor decreases, from the law of proportional transition,
The point at which the normal phase torque becomes maximum shifts to a position where slip is smaller. Since the position where the positive-phase torque becomes maximum shifts to the low-slip side, the minimum point of the torque in the low-slip region of the torque-slip curve generated by the negative-phase current flowing due to the imbalance of the secondary circuit. The torque at the will be raised.

Since the value of the torque at the minimum point increases in this manner, the torque required for acceleration is satisfied, and as a result, acceleration cannot be disabled.

Embodiment 2 Another embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a plan view of a core sheet showing a configuration of a rotor core of a reluctance motor according to a second embodiment of the present invention.

In the rotor core configuration shown in FIG.
Copper loss occurs when an induced current flows through the secondary conductor formed in the flux barrier, and the loss increases the temperature of the secondary conductor and expands the secondary conductor. Due to the expansion of the secondary conductor, the deformation concentrates on the central portion 5 of the bridge between the coupling flux barrier 4 and the outer periphery of the rotor. As a result, the central portion 5 of the coupling flux barrier 4 swells outward, and The diameter increases. As a result of the increased rotor outer diameter, the rotor may rub the inner periphery of the stator, leading to mechanical destruction.

To alleviate this radial expansion,
A radial rib 6 is provided at the center of the combined flux barrier 4. The rib 6 restricts the radial expansion of the central portion 5 of the bridge between the coupling flux barrier 4 and the outer periphery of the rotor, and can suppress mechanical breakage due to the rotor rubbing the stator.

Embodiment 3 Still another embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a plan view of a core sheet showing a configuration of a rotor core of a reluctance motor according to a third embodiment of the present invention.

When an induced current flows through the secondary conductor formed in the flux barrier, copper loss occurs, and the loss causes the temperature of the secondary conductor to rise and the secondary conductor to expand. Due to the expansion of the secondary conductor, the deformation concentrates on the central portion 5 of the bridge between the coupling flux barrier 4 and the outer periphery of the rotor. As a result, the central portion 5 of the coupling flux barrier 4 swells outward, and The diameter increases. As a result of the increase in the rotor outer diameter, the rotor may be rubbed on the inner circumference of the stator, resulting in mechanical destruction.

In order to alleviate the radial expansion, a rib 6 is provided at the center of the combined flux barrier 4, as shown in FIG. Since the space between the ribs 6 is hollow, the expansion of the secondary conductor formed in the coupling flux barrier 4 is concentrated in the direction of the hollow region 7, and expansion in the radial direction is reduced. Further, the radial expansion of the central portion of the coupling flux barrier 4 is restrained by the rib 6, and as a result, mechanical breakage due to the rotor rubbing the stator can be suppressed. The first to third embodiments of the present invention have been described above. In the above description, the case where the number of flux barriers to be bonded is two is described, but the number is not limited to this, and may be three, four or more.

[0019]

According to the reluctance motor of the present invention, a plurality of flux barrier slits having a convex shape in the center direction of the rotor are provided in a rotor core laminated with a magnetic core sheet, and a nonmagnetic conductive slit is provided in the flux barrier slit. A reluctance motor in which a secondary conductor is formed by injecting a conductive material, wherein a flux barrier slit having the shortest slit length among the flux barrier slits and some flux barrier slits are combined to form a combined flux barrier. The torque-slip characteristic at the time of induction start can be improved.

Further, since the radial rib is provided at the center of the coupling flux barrier, the thermal expansion of the secondary conductor can be reduced by the rib, and mechanical breakage can be suppressed.

Further, since the rib provided on the coupling flux barrier is provided with a hollow region, the thermal expansion of the secondary conductor is reduced by the hollow region provided between the ribs, thereby suppressing mechanical breakage. it can.

[Brief description of the drawings]

FIG. 1 is a plan view of a core sheet showing a configuration of a rotor core of a reluctance motor according to a first embodiment.

FIG. 2 is a plan view of a core sheet showing a configuration of a rotor core of a reluctance motor according to a second embodiment.

FIG. 3 is a plan view of a core sheet showing a configuration of a rotor core of a reluctance motor according to a third embodiment.

FIG. 4 is a plan view of a core sheet showing a configuration of a rotor core of a conventional reluctance motor.

[Explanation of symbols]

1 core sheet, 2a to 2f flux barrier slits, 4 combined flux barrier, 5 bridge central part,
6 ribs, 7 hollow areas.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoichi Tamiya 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Michio Nakamoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Norihiro Achiwa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 5H619 AA00 AA01 BB01 BB06 BB22 BB24 PP02 PP04 PP15

Claims (3)

[Claims] A plurality of flux barrier slits having a convex shape in the center direction of the rotor are provided in a rotor core on which a magnetic core sheet is laminated, and a non-magnetic conductive material is injected into the flux barrier slit. A reluctance motor in which a secondary conductor is formed, wherein a flux barrier slit having the shortest slit length among the flux barrier slits and some flux barrier slits are combined to form a combined flux barrier. 2. The reluctance motor according to claim 1, wherein a radial rib is provided at a central portion of the combined flux barrier. 3. The reluctance motor according to claim 2, wherein a hollow region is provided in a rib provided in the joint flux barrier.