JPH05122895A - Magnetic bearing mounting rotary electric machine - Google Patents

Abstract

PURPOSE:To provide a magnetic bearing mounting rotary electric machine capable of bearing a rotary shaft stably and revolving in a rotary electric machine using a magnetic bearing as a bearing element. CONSTITUTION:A magnetic bearing mounting rotary electric machine is constituted of an inductance measuring device 9 measuring inductance of coils of stators 2b of a motor 2 and a magnetic bearing controller 8 positioning a rotor 4a by adjusting a radial position of the rotor 4a in a magnetic bearing 4 to equalize values of inductance detected by the measuring device 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary electric machine equipped with a magnetic bearing, which has an active radial magnetic bearing on the same rotary shaft, and the rotary electric machine and the magnetic bearing form an integral structure.

[0002]

2. Description of the Related Art In a conventional active magnetic bearing device that has been adopted as a bearing element for a rotating electric machine, the rotating shaft may not be stably supported due to the influence of the magnetic attraction of the rotating electric machine. An embodiment of a motor equipped with an active magnetic bearing will be described below with reference to FIGS. 2 and 3.
In FIG. 2, reference numeral 1 is a rotary shaft, 2 is a motor, a motor rotor 2a is fixed to a central portion of the rotary shaft 1, and a motor stator 2b faces the motor rotor 2a and has an air gap on the circumference. Then, it is fixed to the stationary side, and is driven by a motor driving device 3 such as an inverter, and the rotating shaft 1 rotates. Reference numeral 4 denotes an active type radial magnetic bearing, and the radial magnetic bearing rotor 4a is positioned on the left and right sides of the motor 2 in the axial direction and is fixed to the rotary shaft 1. The radial magnetic bearing rotor 4a is located on the circumference of the radial magnetic bearing rotor 4a. It has an air gap and is fixed to the stationary side up, down, left and right. Reference numeral 5 denotes a displacement sensor that detects the axial displacement of the rotary shaft 1 in the radial direction. The displacement sensor 5 is located and attached to each radial magnetic bearing 4. Reference numeral 6 denotes a thrust magnetic bearing, which is mounted by sandwiching a disk provided at the shaft end of the rotary shaft 1 in the axial direction. Reference numeral 7 denotes an axial displacement sensor of the rotary shaft 1, which is attached to the axial end portion of the thrust magnetic bearing 6 side. Reference numeral 8 denotes a magnetic bearing control device, which detects the signals detected by the radial displacement sensor 5 and the thrust displacement sensor.
The magnetic attraction force is controlled by controlling the electric currents of the radial magnetic bearings 4 and the thrust magnetic bearings 6 so that the rotating shaft 1 is stably supported in a non-contact manner.

Next, the operation of the prior art will be described. The rotary shaft 1 includes the radial magnetic bearings 4, the thrust magnetic bearings 6,
It is stably supported in a non-contact manner by the displacement sensors 5, 7 and the control device 8, and is rotated by the motor 2 and the motor drive device 3. Here, the motor 2 produces a rotational force and a magnetic attraction force in the radial direction. If the rotating shaft 1 is located at the shaft center of the stator 2b of the motor 2, this magnetic attracting force balances the magnetic attracting force generated by the N pole and the S pole, but no force is generated in the radial direction on the rotating shaft 1. Actually, misalignment remains due to processing and assembling problems, and a magnetic attraction force in the radial direction is generated. This magnetic attraction force increases as the core displacement increases, and may exceed the limit that can be supported by the radial magnetic bearing 4, and it is necessary to adjust the position of the shaft core after assembly. However, in the sealed type motor as shown in FIG. 2, it is not possible to measure the air gap between the stator 2b of the motor 2 and the motor rotor 2a after the assembly, so that the processing accuracy of each component and the assembly accuracy should be strict. Since the misalignment was prevented from increasing, the production efficiency was extremely poor. Further, since the centering cannot be performed after the assembly, there is a problem that the motor 2 must be remanufactured when the magnetic attraction force is extremely large.

[0004]

As described above, when the conventional magnetic bearing is used in a rotary electric machine such as a motor or a generator, it is affected by a magnetic attraction force generated by a current flowing through the rotary electric machine, and sometimes the rotor is There is a problem that it cannot be stably supported.

The present invention provides a rotary electric machine equipped with a magnetic bearing which can stably support and rotate a rotary shaft without being affected by the rotary electric machine even when the magnetic bearing is used as a bearing element of the rotary electric machine. With the goal.

[0006]

In the present invention, in order to achieve the above object, in a magnetic bearing mounted rotating electric machine having a rotor of a magnetic bearing on the same rotary shaft as the rotating electric machine, each stator of the rotating electric machine Inductance measuring means for measuring the inductance of the coil, and magnetic bearing control means for determining the reference position of the rotor by adjusting the radial direction position of the rotor in the magnetic bearing so that the measured values of the inductance are equal. Prepared for the configuration.

[0007]

The magnetic bearing having the above-described structure can minimize the influence of magnetic attraction caused by the electric current flowing through the rotating electric machine and the misalignment between the rotating electric machine and the radial magnetic bearing that occur after assembly, so that the magnetic bearing does not support poorly. No control instability occurs. In other words, even if a misalignment occurs due to assembly or processing, even in the case of a rotary electric machine, the rotor can be stably supported without being affected by the rotary electric machine.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a sectional view of a three-phase motor equipped with a magnetic bearing according to the present invention. In FIG. 1, 1 is a rotary shaft, 2 is a motor, and a motor rotor 2a is fixed to the center of the rotary shaft 1,
The motor stator 2b has a circumferential air gap facing the motor rotor 2a and is fixed to the stationary side. The motor stator 2b is driven by a motor driving device 3 such as an inverter to rotate the rotating shaft 1. 4 is an active radial magnetic bearing,
The radial magnetic bearing rotor 4a is located on the left and right sides of the motor 2 in the axial direction and is fixed to the rotary shaft 1. The motor stator 4b is stationary with an air gap on the circumference of the radial magnetic bearing rotor 4a. It is fixed to the top, bottom, left and right. 5
Is a displacement sensor that detects the axial displacement of the rotary shaft 1 in the radial direction, and is mounted on the side of each radial magnetic bearing 4. Reference numeral 6 denotes a thrust magnetic bearing, which is mounted by sandwiching a disk provided at the shaft end of the rotary shaft 1 in the axial direction. Reference numeral 7 denotes a displacement sensor for detecting the axial displacement of the rotary shaft 1, which is attached to the axial end portion of the thrust magnetic bearing 6 side. Reference numeral 8 denotes a magnetic bearing control device, which controls the currents of the radial magnetic bearings 4 and the thrust magnetic bearings 6 so that the rotary shaft 1 is stably supported in a non-contact manner by the detection signals of the radial displacement sensors 5 and the thrust displacement sensors. To control the magnetic attraction force. Reference numeral 9 is an inductance measuring device, which is a motor 2
The respective inductances between the lead wires U, V, W of the stator 2b are measured, and the measurement results are displayed or transmitted to the magnetic bearing control device 8.

Next, the operation of the present invention will be described. The rotary shaft 1 is stably supported in a non-contact manner by the radial magnetic bearings 4, the thrust magnetic bearings 6, the displacement sensors 5, 7 and the control device 8, and is rotated by the motor 2 and the motor drive device 3. Here, the motor 2 produces a rotational force and a magnetic attraction force in the radial direction. However, if the motor 2 has the rotor 2a at the axial center of the stator 2b,
This magnetic attraction force in the radial direction cancels each other out at 180 ° symmetrical positions of the rotor 2a and becomes zero. Therefore, in the present invention, the inductance between the lead wires of the stator 2b of the motor 2 is measured by the inductance measuring device 9,
The rotor 4 in the stator 4b of the active radial magnetic bearing 4 is adjusted so that the measured inductance values are equal.
The position of a is adjusted by the magnetic bearing control device 8. The inductance between the lead wires of the stator 2b of the motor 2 is
Since the inductance at the 120 ° symmetrical position of the stator 2b is a function of the air gap at each position, the measured inductance values between the lead wires of the stator 2b are made equal. That is, the rotor 2a is positioned at the shaft center of the stator 2b. The adjustment of the position of the shaft center may be performed manually by the value of the inductance measuring device 9 or automatically by providing an automatic adjusting device in the magnetic bearing control device 8.

[0010]

Since the magnetic bearing of the present invention is constructed as described above, it is possible to stably support the rotor without being affected by the magnetic attraction force of the rotating electric machine. The performance will not be degraded, and the reliability will be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a motor that employs a magnetic bearing according to the present invention.

FIG. 2 is a vertical cross-sectional view of a motor using a conventional magnetic bearing.

[Explanation of symbols]

 1 ... Rotary shaft 2 ... Motor 3 ... Motor drive device 4 ... Radial magnetic bearing 5 ... Radial displacement sensor 6 ... Thrust magnetic bearing 7 ... Thrust displacement sensor 8 ... Magnetic bearing control device 9 ... Inductance measuring device 2a ... Motor rotor 2b ... Motor stator 4a ... Radial magnetic bearing rotor 4b ... Radial magnetic bearing stator

Claims (1)

[Claims] 1. In a rotary electric machine equipped with a magnetic bearing having a rotor of a rotary electric machine and a rotor of a magnetic bearing on the same rotary shaft, a means for measuring the inductance of each stator coil of the rotary electric machine and the measured value of the inductance are equal. And a magnetic bearing control means for controlling the radial direction position of the rotor in the magnetic bearing so as to determine the reference position of the rotor.