JPS596261Y2 - Controlled magnetic bearing device - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a controlled magnetic bearing device.

As shown in FIG. 1, in the conventional controlled magnetic bearing device, a rotating shaft 1 is rotatably supported by a radial front magnetic bearing 2 and a rear magnetic bearing 3.

4 and 5 are position detectors for detecting the displacement of the rotating shaft 1 in the radial direction, which are provided near the magnetic bearings 2 and 3, respectively;
is a control circuit that controls the detection signals of the position detectors 4 and 5.

The front magnetic bearing 2 has an electromagnetic coil 10 wound around an iron core 9 of a stator 8, and the rear magnetic bearing 3 has an electromagnetic coil 13 wound around an iron core 12 of a stator 11.

a, l), and c represent the axial direction of the rotating shaft 1 of the front position detector 4 and the front magnetic bearing 2, the front magnetic bearing 2 and the rear magnetic bearing 3, and the rear magnetic bearing 3 and the rear position detector 5, respectively. This is the distance between the mounting center positions.

In the plane perpendicular to the axis of the rotating shaft 1, the front X direction (
As shown in Fig. 2, the front side The stator of the magnetic bearing 2 is arranged such that two Fx stators 8x and two Fy stators 8y are orthogonal to each other.

In each stator ax, ay, electromagnetic coils 10 x, 10 V are wound around iron cores 9X, 9y, respectively.

The front position detector 4 is composed of an Fx position detector 4X and an Fy position detector 4y that are arranged perpendicular to each other, and the control circuit 6 corresponds to the Fx position detector 4X and the Fy position detector 4y, respectively. It consists of an Fx control circuit 6x and an Fy control circuit 6y.

The detection signals detected by the Fx position detector 4X and the Fy position detector 4y are sent to the Fx control circuit 6X and the Fy control circuit 6.
y, and is applied to the Fx electromagnetic coil 10X and the lower y electromagnetic coil 10y, respectively.

The magnetic bearing 3 provided on the rear side, the electromagnetic coil 13 wound around the iron core 12 of the stator 11, the position detector 5, and the control circuit 7 are arranged in the same way as those provided on the front side. As shown in the block diagram in FIG. 3, the detection signals detected by the Rx position detector 5X and the Ry position detector 5y are controlled by the RX control circuit 7X and the Ry control circuit 7y, and are sent to the Rx electromagnetic coil 13X and the Ry electromagnetic coil. 13y, respectively.

However, the conventional controlled magnetic bearing device is subject to structural limitations in design or assembly, and the magnetic bearings 2 and 3 and the position detectors 4 and 5 are spaced apart from each other in the axial direction of the rotating shaft 1. It was necessary to install it with

Therefore, as shown in Fig. 4, the axial dimension of the rotating shaft 1 is plotted on the horizontal axis, and the X-direction displacement of the rotating shaft 1 is plotted on the vertical axis, and the X-direction displacement detected by the Fx position detector 4X and the Rx position are detected. An example of a case where there is a difference in the displacement in the X direction detected by the device 5X is as follows.
xf is the displacement in the X direction detected by the Fx position detector 4X, x
r is the X direction displacement detected by the Rx position detector 5X, Uf
is the displacement of the rotating shaft 1 in the X direction at the center position of the front magnetic bearing 2, and Ur is the displacement of the rotating shaft 1 in the X direction at the center position of the rear magnetic bearing 3.

If the rotating shaft 1 is a rigid body and a + b + c = L, then xf
The following relationship holds between , xr, Uf, and Ur.

That is, as is clear from the above equation, the X-direction displacements Ux and Uy of the rotating shaft 1 at the center positions of the magnetic bearings 2 and 3 are
Since it is a function of the directional displacements xf and xr, for example, the X-direction displacement U of the rotating shaft 1 at the center position of the front magnetic bearing 2
If we try to control f only by the X-direction displacement xf detected by the Fx position detector 4X, axr/j in equation (1)
It is unavoidable that errors will occur.

Therefore, the subordinate control type magnetic bearing device had the disadvantage that it was difficult to accurately control the position of the rotating shaft 1 supported by the magnetic bearings 2 and 3, and high precision could not be obtained.

Furthermore, if position detectors 4 and 5 are provided on the left and right sides of each magnetic bearing 2 and 3, and the detection signals of the left and right position detectors of each magnetic bearing 2 and 3 are controlled by control circuits 6 and 7, the control circuit 6 ,7
Although it is possible to eliminate errors in the control signals from the controller, it has the disadvantage that the structure becomes complicated.

This idea is intended to solve the above drawbacks,
Two sets of radial type magnetic bearings that rotatably support the rotating shaft, position detectors that detect mutually orthogonal radial displacement of the rotating shaft near each type of magnetic bearing, and a position detector that detects the input current of the magnetic bearing. In a controlled magnetic bearing device that has a control circuit that is controlled by a detection signal from a position detector, by providing a correction circuit that corrects an error in the control signal caused by the mounting position of the magnetic bearing and the position detector in the rotation axis direction, The purpose of this invention is to obtain a high-precision controlled magnetic bearing device with a simple structure and low manufacturing cost.

An embodiment of this invention will be described below based on the drawings.

In FIG. 5, a rotating shaft 21 is rotatably supported by a radial front magnetic bearing 22 and a rear magnetic bearing 23. As shown in FIG.

Reference numerals 24 and 25 indicate position detectors for detecting displacement in the radial direction of the rotating shaft 21, which are provided near the magnetic bearings 22 and 23, respectively. Reference numerals 26 and 27 indicate control circuits that control the detection signals of the position detectors 24 and 25. be.

The front magnetic bearing 22 has an electromagnetic coil 30 wound around an iron core 29 of a stator 28, and the rear magnetic bearing 23 has an electromagnetic coil 33 wound around an iron core 32 of a stator 31.

34 is a correction circuit for correcting the detection signals of the position detectors 24 and 25.

As shown in FIG. 6, similarly to the conventional controlled magnetic bearing device described above, the position detectors 24 and 25 include an Fx position detector 24 and an X and Ry position detector 2 disposed orthogonally to each other.
4y, and an Rx position detector 25X and an Rx position detector 25y, respectively, and a front magnetic bearing 22
is Fx electromagnetic coil 30 X and Fy electromagnetic coil 30
y, the rear magnetic bearing 23 has an Rx electromagnetic coil 33X and a Ry electromagnetic coil 33y, and the control circuit 26
．． 27 is each electromagnetic coil 30 x, 30 Y, [3
Fx control circuit 2 that controls the input current of x, 33 y
6 X and Fy control circuits 26y, and Rx control circuits 27X and Ry control circuits 27y.

The correction circuit 34 is an X-direction correction circuit 3 that corrects the detection signals of the Fx position detector 24X and the Rx position detector 25X.
4 X and Fy position detectors 24 y and Ry position detectors 25 y direction correction circuit 34 for correcting detection signals of y
It is composed of y.

The rotary shaft 21 supported by the magnetic bearings 22 and 23 of the controlled magnetic bearing device of this invention constructed as described above is such that the X-direction displacement of the rotary shaft 21 is detected by the Fx position detectors 24X and Rx.
The detection signal is detected by the position detector 25 Each control signal is applied to the Fx electromagnetic coil 30X of the front magnetic bearing and the Rx electromagnetic coil 33X of the rear magnetic bearing, respectively, to control each magnetic bearing 22. 23 is controlled in the X direction, and similarly the displacement in the y direction of the rotating shaft 21 is Fy.
The detection signals are detected by the position detector 24 y and the Ry position detector 25 y, and are corrected by the y direction correction circuit 34 y, and then passed through the Fy control circuit 26 y and the Ry control circuit 27y, respectively. Each control signal from the control circuit 27y is sent to the FY electromagnetic coil 30y of the front magnetic bearing and the Ry electromagnetic coil 30y of the rear magnetic bearing.
y is applied to control the position of each magnetic bearing 22, 23 in the y direction at its mounting position.

The mounting positions of the magnetic bearings 22, 23 and the position detectors 24, 25 are determined by X based on the mounting distances a, b, and C in the axial direction of the rotating shaft 21, which are determined from the design, and the equations (1) and (2) above. The direction correction circuit 34X is set, and the y direction correction circuit 34 is similarly set.
If y is set, the position detector 24. 25 and a control circuit 26 for controlling the position of the magnetic bearings 22 and 23; The occurrence of an error with the control signal from 27 is eliminated.

As explained above, the controlled magnetic bearing device of this invention has the following features:
Two sets of radial magnetic bearings that support the rotating shaft, a position detector that detects mutually orthogonal radial displacement of the rotating shaft near each magnetic bearing, and a position detector that detects the input current of the magnetic bearings. In a controlled magnetic bearing device that has a control circuit that is controlled by a detection signal, by providing a correction circuit that corrects errors in the control signal caused by the mounting position of the magnetic bearing and position detector in the rotational axis direction, the controlled magnetic bearing The device has a simple structure and has the advantage of being able to achieve high rotation accuracy at low manufacturing costs.

[Brief explanation of the drawing]

Figures 1 to 4 show an example of a conventional controlled magnetic bearing device, with Figure 1 being a longitudinal cross-sectional view of the main part, and Figure 2 taken in the direction of the arrow on line A-A in Figure 1. Principle explanatory diagram, 3rd
The figure is a block diagram, Figure 4 is an explanatory diagram showing the relationship between the axial position of the rotary shaft and the displacement of the rotary shaft in the X direction, and Figures 5 and 6 are examples of the controlled magnetic bearing device of this invention. FIG. 5 is a vertical sectional view of the main part, and FIG. 6 is a block diagram. 21... Rotating shaft, 22. 23... Radial magnetic bearing, 24, 25... Position detector, 26. 27...
- Control circuit, 34... correction circuit.

Claims (1)

[Scope of utility model registration request] two sets of radial magnetic bearings that rotatably support a rotating shaft; a position detection device that detects mutually orthogonal radial displacement of the rotating shaft near each magnetic bearing; and an input current to the magnetic bearing. and a control circuit that controls the magnetic bearing using the detection signal of the position detector, correcting an error in the control signal caused by mutual mounting positions of the magnetic bearing and the rotation shaft in the axial direction of the rotation shaft. 1. A controlled magnetic bearing device, characterized in that it is provided with a correction circuit.