JP4344601B2 - Magnetic bearing low disturbance control device - Google Patents

Description

  The present invention relates to a low disturbance control device that reduces disturbance generated by a magnetic bearing that supports a rotating body (rotor) in a non-contact manner in all frequency ranges including a servo resonance frequency range of the magnetic bearing.

  Conventionally, as a disturbance suppression device for a magnetic bearing, there is a synchronous interference compensation device. The synchronous disturbance compensating apparatus holds the rotor at a preset radial position based on the rotor radial position x, y detecting means and the rotor radial position x, y output from the two-input adder. In contrast to a normal magnetic bearing device having a control circuit for supplying current to the bearing electromagnet coil, a processing circuit is arranged between the rotor radial position detecting means and the control circuit. This processing circuit acts as a band elimination filter centered on the frequency of the axial direction rotor rotational speed, and removes the rotational synchronization component from the rotor radial position x, y, thereby significantly reducing the bearing rigidity in the rotational synchronization frequency range. . Thereby, since the rotor rotates around the inertial main shaft, vibration of the force generated by the magnetic bearing device when the rotor rotates, that is, disturbance can be suppressed (for example, refer to Patent Document 1).

  Conventionally, there is a critical frequency attenuating device as a device for facilitating the passage of the magnetic bearing in the resonance frequency range. This critical frequency attenuating device has a configuration in which a digital circuit is arranged in parallel with a phase advance network with respect to a normal magnetic bearing device. This digital circuit acts as a means for selectively amplifying the phase or phase gain of the rotor radial position x, y in a frequency band centered at a frequency equal to the axial rotor rotational speed, It is possible to increase the phase of the magnetic bearing control system, that is, the phase advance gain. As a result, the bearing rigidity is increased in the rotation synchronization frequency range, and in particular, in the resonance frequency range of the magnetic bearing, it is possible to suppress the rotor swing amount and easily exceed the resonance frequency range (for example, Patent Document 2). reference).

  Conventionally, there is a magnetic bearing control device as a rotor disturbance suppressing device. In this magnetic bearing control device, the CPU adjusts the gain for adjusting the applicability of the ABS control equivalent to the synchronous disturbance compensation device, the N-cross control equivalent to the critical frequency attenuation device, and the FF control according to the axial direction rotor rotational speed. It is configured to set. Therefore, when the rotational speed of the rotor in the axial direction is outside the resonance frequency range of the magnetic bearing, only the ABS control is applied to reduce the bearing rigidity in the rotational synchronization frequency range, thereby realizing low disturbance due to the rotor rotation around the inertia spindle. When the rotor rotation speed is in the resonance frequency range of the magnetic bearing, the N cross control or FF control is applied to increase the bearing rigidity in the rotation synchronization frequency range, thereby reducing the rotor swing amount. Can be easily passed (see, for example, Patent Document 3).

Japanese Examined Patent Publication No. 60-14929 (pages 3 to 5, FIGS. 4 and 8) Japanese Patent Laid-Open No. 52-93853 (pages 3 to 4, FIGS. 4 and 6) JP-A-06-193633 (pages 10-14, FIG. 1)

  In the control method of Patent Document 1, the bearing rigidity is extremely lowered only in the rotor rotation synchronization frequency region, so that the rotor is rotated around the inertia main shaft to reduce disturbance. In order to achieve low disturbance with this conventional control method, it is necessary to set the amount of decrease in bearing rigidity in the rotation synchronization frequency range to a predetermined value or more. However, the decrease in bearing rigidity in the servo resonance frequency range of magnetic bearings. When the amount is increased, the stable flying of the rotor is impaired, so that there is a problem that sufficient disturbance suppression cannot be realized in the servo resonance frequency range.

  Further, in the control methods of Patent Documents 2 and 3, the bearing rigidity in the rotation synchronous frequency region can be increased to allow easy passage of the resonance frequency region by suppressing the rotor swing amount. Furthermore, by significantly lowering the bearing rigidity only in the rotor rotation synchronization frequency range, the rotor can be rotated around the inertia main shaft to reduce disturbance, but in the servo resonance frequency range, by increasing the bearing rigidity, There is a problem that the occurrence disturbance increases.

  The present invention has been made to solve the above-described problems, and is a low disturbance control that reduces the disturbance generated by the magnetic bearing device in the entire frequency range including the servo resonance frequency range of the magnetic bearing. The object is to provide a device.

A first disturbance control device for a magnetic bearing according to a first aspect of the present invention is a fixed magnetic bearing comprising a plurality of electromagnets that levitate a rotor by electromagnetic force, with a radial direction as an X axis and a Y axis, and a central axis as a Z axis. In the coordinate system, a radial translational displacement in which the geometric center axis of the rotor translates in the radial direction, and an axial translational displacement in which the geometric center axis of the rotor translates in the axial direction (Z-axis direction) of the fixed coordinate system. 5-degree-of-freedom rotor displacement and axial direction consisting of a 3-degree-of-freedom rotor displacement and a 2-degree-of-freedom rotor displacement in which the geometric center axis of the rotor rotates in a plane including the Z-axis of the fixed coordinate system Displacement detecting means for detecting information related to the rotor rotation angle (rotor displacement information);
A rotor displacement calculator for converting the output of the displacement detector into the 5-degree-of-freedom rotor displacement; and a bearing force for controlling the rotor to a predetermined position of the magnetic bearing based on the output of the rotor displacement calculator. A control command output means for outputting a radial direction and axial direction bearing force command, and a radial direction bearing moment command serving as a bearing force for controlling the radial rotational displacement of the rotor;
Based on the output of the rotor displacement calculator, a gap length calculator that outputs the gap length between each of the electromagnets and the rotor ;
The electromagnet for realizing the radial direction and axial direction bearing force command and the radial direction bearing moment command output from the control command output means based on the output of the gap length calculator and the output of the control command output means. A bearing control system including a power distributor that distributes and supplies a supply current to each ;
Based on the rotor rotational angle in the axial direction of the rotor, the radial bearing force command output by the control command output means in the bearing control system is expressed as follows: the geometric center axis of the rotor is the Z axis, and the direction perpendicular to the Z axis is X A rotary coordinate converter for converting into a rotary coordinate system representation that rotates about the Z axis with the rotor as an axis and a Y axis;
LPF for extracting the rotor rotation synchronization component of the output of the rotary coordinate converter;
An integrator that integrates the output of the LPF and outputs a radial translational displacement of a rotating coordinate system that translates in the radial direction;
Based on the axial rotor rotation angle of the rotor, the radial translation displacement output from the integrator is converted into the fixed coordinate system representation so that the center of gravity of the rotor is located at the origin of the rotary coordinate system. translational displacement command control system that includes a fixed coordinate converter for calculating a radial translational displacement command for translating the geometric center axis of the radial direction,
With
The bearing control system controls the electromagnet to control the flying position of the rotor to a predetermined position by a radial translational displacement command converted to the fixed coordinate system.

A second disturbance control device for a magnetic bearing according to the present invention is a magnetic bearing composed of a plurality of electromagnets that levitates a rotor by electromagnetic force, with a radial direction as an X axis and a Y axis, and a central axis as a Z axis. In the coordinate system, a radial translational displacement in which the geometric center axis of the rotor translates in the radial direction, and an axial translational displacement in which the geometric center axis of the rotor translates in the axial direction (Z-axis direction) of the fixed coordinate system. 5-degree-of-freedom rotor displacement and axial direction consisting of a 3-degree-of-freedom rotor displacement and a 2-degree-of-freedom rotor displacement in which the geometric center axis of the rotor rotates in a plane including the Z-axis of the fixed coordinate system Displacement detecting means for detecting information related to the rotor rotation angle (rotor displacement information);
A rotor displacement calculator for converting the output of the displacement detection means into the 5-degree-of-freedom rotor displacement;
Based on the output of the rotor displacement calculator, a radial and axial direction bearing force command that becomes a bearing force for controlling the rotor to a predetermined position of the magnetic bearing, and a bearing force for controlling the radial rotational displacement of the rotor Control command output means for outputting a radial bearing moment command,
Based on the output of the rotor displacement calculator, a gap length calculator that outputs the gap length between each of the electromagnets and the rotor ;
The electromagnet for realizing the radial direction and axial direction bearing force command and the radial direction bearing moment command output from the control command output means based on the output of the gap length calculator and the output of the control command output means. A bearing control system including a power distributor that distributes and supplies a supply current to each ;
Based on the rotor rotational angle in the axial direction of the rotor, the radial bearing moment command output by the control command output means in the bearing control system is expressed as follows: the geometric center axis of the rotor is the Z axis, and the direction perpendicular to the Z axis is X A rotary coordinate converter that converts the rotary coordinate system to rotate around the Z axis together with the rotor as an axis and a Y axis;
LPF for extracting the rotor rotation synchronization component of the output of the rotary coordinate converter;
An integrator for outputting a radial rotational displacement of the rotating coordinate system that rotates in the radial direction by integrating the output of the LPF,
Based on the rotor rotational angle in the axial direction of the rotor, the radial rotational displacement output from the integrator is converted into the fixed coordinate system representation so that the inertial main shaft of the rotor is parallel to the central axis of the magnetic bearing. A rotational displacement command control system comprising: a fixed coordinate converter that calculates a radial rotational displacement command for rotating the geometric center axis of the rotor in a plane including the Z axis of the fixed coordinate system;
With
The bearing control system controls the electromagnet to control the flying position of the rotor to a predetermined position by a radial rotational displacement command converted into the fixed coordinate system.

  According to the first disturbance control device for a magnetic bearing according to the present invention, since the position of the center of gravity of the rotor is positioned on the rotational coordinate system Z-axis, the disturbance force caused by the rotor unbalance is reduced. Can be reduced.

  According to the second disturbance control device for a magnetic bearing according to the present invention, since the rotor inertia main shaft is made parallel to the magnetic bearing central axis, the disturbance moment caused by rotor dynamic imbalance is reduced. Can do.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing an arrangement example of a rotor, an electromagnet, and a displacement detection means that are components of a magnetic bearing device, where (a) is a front view and (b) is a plan view.

  As shown in FIG. 1, the magnetic bearing device according to the first embodiment includes a rotor 1, a magnetic bearing composed of an electromagnet 2 that floats the rotor 1 to a predetermined position by electromagnetic force, and displacement of the rotor 1 from the center of the magnetic bearing. Displacement detecting means 3 for detecting is provided, and the X axis, the Y axis, and the Z axis are coordinate axes of a fixed coordinate system fixed to a magnetic bearing (fixed to a stator not shown), and the Z axis Is a magnetic bearing central axis (axial direction), X axis and Y axis are radial axes perpendicular to and perpendicular to the magnetic bearing central axis, and the origin of the fixed coordinate system is the geometric center position of the rotor 1.

  Further, in the magnetic bearing device for controlling the three-degree-of-freedom translational displacements X, Y, Z and the radial two-degree-of-freedom rotational displacements θx, θy of the rotor 1, ten electromagnets 2a-2j around the cylindrical rotor 1 and Ten displacement detection means 3a to 3j are arranged.

  In the rotor 1, a radial translational displacement X, Y in which the geometric center axis of the rotor 1 translates in the radial direction from the origin of the fixed coordinate system, and the geometric center axis of the rotor 1 translates in the axial direction (Z-axis direction) of the fixed coordinates. A rotor displacement such as an axial translational displacement Z that moves, and a radial rotational displacement θx and θy in which the geometric center axis of the rotor 1 rotates in a plane including the Z axis of the fixed coordinate system occurs.

  In the magnetic bearing device having this configuration, the radial translational displacements X and Y of the rotor 1 and the radial rotational displacement θx, based on the rotor displacement information (hereinafter referred to as rotor displacement information) output from the displacement detectors 3a to 3h. θy can be calculated, and the axial translational displacement Z of the rotor 1 can be calculated from the rotor displacement information output from the displacement detectors 3i to 3j (that is, the 5-degree-of-freedom rotor displacement X, Y, Z, θx and θy can be calculated). Moreover, the radial bearing force and the radial bearing moment acting on the rotor 1 can be controlled by the electromagnetic force generated by the electromagnets 2a to 2h, and the axial acting on the rotor 1 by the electromagnetic force generated by the electromagnets 2i to 2j. The directional bearing force can be controlled.

  2A and 2B are a front view and a cross-sectional view taken along line AA of a magnetic bearing device in which six electromagnets 2a to 2f and six displacement detecting means 3a to 3f are arranged around the inclined magnetic pole ring-shaped rotor 1. FIG. 5 degrees of freedom rotor displacement X, Y, Z, θx, θy can be calculated from the rotor displacement information output from the displacement detection means 3a-3f, and the electromagnetic force generated by the electromagnets 2a-2f Thus, the radial bearing force, the axial bearing force and the radial bearing moment acting on the rotor can be controlled.

  FIG. 3 is a block diagram for explaining the first embodiment of the low disturbance control device according to the present invention, and FIG. 4 is a rotor radial cross-sectional view for explaining the first embodiment.

  As shown in FIG. 3, the low disturbance control device includes bearing force commands Fx, Fy, Fz which are bearing forces for controlling the geometric central axis of the rotor 1 to a predetermined position of the magnetic bearing, and the radial of the rotor 1. A radial translational displacement command of the rotor 1 is calculated from the bearing force commands Fx and Fy to the bearing control system 10 and the bearing control system 10 that output radial bearing moment commands Nx and Ny that are bearing forces that control the rotational displacement of the direction. The translation displacement command control system 20 is provided.

The bearing control system 10 outputs from the rotor 1, the electromagnet 2 that floats the rotor 1 by electromagnetic force, and the component 11 including the displacement detector 3 that detects the displacement of the rotor 1, and n displacement detectors (displacement sensors) 3. Based on the rotor displacement information S1, S2... Sn, the 5-degree-of-freedom rotor displacement comprising the 3-degree-of-freedom translational displacements X, Y, Z of the rotor 1 and the radial direction 2-degree-of-freedom rotational displacements θx, θy is calculated. Based on the rotor displacement calculator 12, 5-degree-of-freedom rotor displacement X, Y, Z, θx, θy, gap lengths G1, G2,... Gn in each of the n electromagnets 2 constituting the magnetic bearing are calculated. Gap length calculator 13, rotor displacement deviation (5-degree-of-freedom rotor displacement X, Y, Z, θx, θy and radial translational displacement commands Xc, Yc, axial translational displacement command Zc, radial rotation) Position command Shitaxc, bearing force command Fx on the basis of the deviation between the θyc), Fy, Fz and radial bearing moment command Nx, calculates the Ny, PID controller 15 as a control command output means, bearing force command Fx, Fy , Fz, bearing moment commands Nx, Ny and bearing electromagnet gap lengths G1, G2,... Gn, supply currents I1, I2,. A power distributor 14 is provided. Only the PID controller 15x for the X-axis direction translational movement and the PID controller 15y for the Y-axis direction translational movement are illustrated.

  Further, the translational displacement command control system 20 converts the radial bearing force commands Fx and Fy output from the bearing control system 10 into rotational coordinate system expressions Fxr and Fyr fixed to the rotor using the axial direction rotor rotation angle θz. The rotation low-frequency band is set to a narrow band of about 1 Hz with respect to the rotary coordinate converter 21 to be converted and the rotational coordinate system representation Fxr, Fyr of the radial direction bearing force command, so that the rotor rotation synchronization of the radial direction bearing force command is performed. These are the outputs of an integrator 23 and an integrator 23 that integrate the outputs of LPF (low-pass filter) 22 and LPF 22 that extract only components, and output rotational coordinate system expressions Xcr and Ycr of the radial translational displacement command of the rotor 1. Rotational coordinate system expression Xcr, Ycr of radial direction translational displacement command is expressed in fixed coordinate system using axial direction rotor rotation angle θz c, and a fixed coordinate converter 24 which converts the Yc.

  FIG. 4 is a cross-sectional view showing a cross section in the radial direction of the rotor. FIG. 4 (a) is just after applying the translational displacement command control system, and FIG. 4 (b) is enough time after applying the translational displacement command control system. The later state is shown. In FIG. 4, the coordinate axes of the rotational coordinate system perpendicular to the rotational axis of the rotor 1 and orthogonal to each other and fixed to the rotor are Xr and Yr. The origin of the rotational coordinate system is the same as the fixed coordinate system origin. I'm doing it. Further, the center of gravity position of the rotor is G, the geometrical center position of the rotor determined by the rotor displacement information detected by the displacement detecting means is S, the swinging force caused by the static imbalance of the rotor is 30, and the rotational coordinate converter 21 outputs 31 is a vector whose elements are the rotational coordinate system representations Fxr and Fyr of the radial bearing force command, and 32 is a vector whose elements are the rotational coordinate system representations Xcr and Ycr of the radial translational displacement command.

Next, the operation will be described. In the bearing control system 10, rotor displacement information Si (i = 1, 2,..., N) output from a component 11 comprising an electromagnet / rotor / displacement detecting means for detecting rotor displacement is transmitted by a rotor displacement calculator 12. The rotor is converted into a 5-degree-of-freedom rotor displacement consisting of a 3-degree-of-freedom translational displacement X, Y, Z of the rotor and a radial direction 2-degree-of-freedom rotational displacement θx, θy. The 5-degree-of-freedom rotor displacement is fed back, and a deviation signal between the 5-degree-of-freedom rotor displacement and the radial translational displacement commands Xc and Yc, the axial translational displacement command Zc, and the radial rotational displacement commands θxc and θyc is sent to the PID controller 15. input. The PID controller 15 calculates and outputs bearing force commands Fx, Fy, Fz and radial bearing moment commands Nx, Ny for the magnetic bearing based on the input deviation signal. The gap length calculator 13 calculates gap lengths G1, G2,..., Gn in each of the n electromagnets constituting the magnetic bearing based on the 5-degree-of-freedom rotor displacement output from the rotor displacement calculator 12. Output. In the power distributor 14, in the bearing electromagnet gap length Gi (i = 1, 2,..., N) output from the gap length calculator 13, the bearing force commands Fx, Fy, Fz output from the PID controller 15 and In order to realize the radial bearing moment commands Nx, Ny, supply currents I1, I2,..., In are distributed and supplied to each of the n electromagnets.
However, in FIG. 3, for the sake of simplicity, the feedback loop for the axial translational motion and the radial rotational motion is not shown.

  By such operation of the bearing control system 10, the rotor floating position coincides with the radial translational displacement commands Xc and Yc, the axial translational displacement command Zc, and the radial rotational displacement commands θxc and θyc (5-degree-of-freedom rotor displacement command). It becomes possible to control to do.

  However, in the conventional magnetic bearing control device, the rotor displacement command of 5 degrees of freedom is always set to zero, and therefore the rotor radial cross-sectional view when the axial direction rotor rotational speed is lower than the position control band of the bearing control system 10 is Ideally, this is as shown in FIG. That is, when viewed from the rotational coordinate system Xr-Yr, the rotor geometric center position S is located at the origin of the rotational coordinate system, and the rotor center-of-gravity position G is separated from the rotor geometric center position S by a distance corresponding to the rotor unbalance. Located at a point. As a result, a swinging force (centrifugal force) 30 caused by static imbalance acts on the rotor center of gravity position G, and the rotor floating position, that is, the rotor geometric center position S is determined as the origin of the rotational coordinate system under the action of the swinging force 30. Therefore, the vector 31 having the rotational coordinate system representations Fxr and Fyr of the radial bearing force command as the elements becomes the swinging force 30 and the reverse polarity vector. At this time, the reaction of the radial bearing force acting on the rotor acts on the stator, which becomes the main factor of vibration of the force transmitted to the housing of the magnetic bearing device, that is, disturbance.

  Therefore, in the low disturbance control device according to the first embodiment, the translation displacement command control system 20 is provided, and the translation displacement command control system 20 is based on the radial direction bearing force commands Fx and Fy and the axial direction rotor rotation angle θz. The radial translational displacement commands Xc and Yc are controlled so that the rotor center-of-gravity position G is located at the origin of the rotational coordinate system.

  The radial direction bearing force commands Fx and Fy and the axial direction rotor rotation angle θz output from the PID controller 15 are input to the rotational coordinate converter 21 of the translational displacement command control system 20, and the rotational coordinate converter 21 receives the radial direction bearing force. The rotational coordinate system representations Fxr and Fyr of the command are calculated by the following expressions (1) and (2).

  The rotational coordinate system representations Fxr and Fyr of the radial bearing force command are input to the LPF 22 in which the low pass frequency band is set to a narrow band of about 1 Hz. Here, only the rotor rotation synchronization component of the radial bearing force command is extracted. Is done. The output of the LPF 22 is represented by a vector 31 in FIG. 4A, and as a result of integration by the integrator 23, the rotational coordinate system representations Xcr and Ycr of the radial translational displacement command represented by the vector 32 are integrated into the integrator 23. Is output from. In the fixed coordinate converter 24, the rotational coordinate system representation Xcr, Ycr of the radial translational displacement command, which is the output of the integrator 23, is expressed by the following equations (3), (4) using the axial direction rotor rotation angle θz. It is converted to a radial translational displacement command Xc, Yc expressed in a fixed coordinate system and output to the bearing control system 10.

  The bearing control system 10 controls the rotor flying position so as to follow the radial translational displacement commands Xc and Yc thus obtained, so that the rotor geometric center position S moves on the rotating coordinate system according to the vector 32 and is in a steady state. Then, as shown in FIG. 4B, the rotor center-of-gravity position G is located at the origin of the rotational coordinate system. As a result, both the run-out force 30 caused by the rotor static imbalance and the rotational coordinate system representation 31 of the radial bearing force command converge to the zero vector, and thus act on the radial bearing force acting on the rotor 1 and the stator. As a result of the reduction of both radial bearing force reactions, the level of disturbance forces due to rotor static imbalance is reduced.

  As described above, the low disturbance control device according to the first embodiment allows the rotor center-of-gravity position G to be positioned on the magnetic bearing rotating shaft, particularly when the axial direction rotor rotational speed is within the position control band of the bearing control system 10. Thus, the disturbance force caused by the rotor unbalance can be reduced.

  Further, the LPF 22 in the translational displacement command control system 20 can easily remove signal components belonging to a frequency region other than the rotor rotation synchronization component.

Embodiment 2. FIG.
FIG. 5 is a block diagram for explaining the second embodiment of the low disturbance control device according to the present invention, and FIG. 6 is a rotor radial direction sectional view for explaining the second embodiment. 6, the same reference numerals as those in FIGS. 3 and 4 denote the same or corresponding parts.

  6 (a), 6 (c) and 6 (e) show the amount of phase advance in the fixed coordinate converter / phase converter 25 when the rotational speed of the rotor in the axial direction is increased to the servo resonance frequency range of the magnetic bearing or higher. FIGS. 6 (b), (d), and (f) are respectively shown in FIGS. 6 (a), (c), and (e). ) After a sufficient time has elapsed after the translation displacement command control system is applied.

As shown in FIG. 5, lower perturbation of the control device of the second embodiment, PI controller 16 in the position control loop, P controller 17 to perform the gain K _D in the speed control loop, based on the rotor displacement rotor Xcr ′ and Ycr ′, which are the outputs of the differentiator 18 and integrator 23 for calculating the speed, are converted into a fixed coordinate system expression, and predetermined according to the axial direction rotor rotational speed in consideration of the phase characteristics of the bearing control system. The fixed coordinate converter / phase converter 25 is provided which outputs a signal obtained by advancing the phase amount as radial translational displacement commands Xc and Yc of the bearing control system 10.

  In FIG. 6, a predetermined phase amount advanced according to the axial direction rotor rotational speed by the fixed coordinate converter / phase converter 25 is α, the rotor rotational direction is 33, and the moving direction vector of the rotor geometric center position S is 34.

  Next, the operation will be described. In the bearing control system 10, the rotor displacement information Si (i = 1, 2,..., N) output from the electromagnet / rotor / displacement detecting means 11 is converted by the rotor displacement calculator 12 into the three-degree-of-freedom translational displacement X, It is converted into a 5-degree-of-freedom rotor displacement comprising Y, Z and radial direction 2-degree-of-freedom rotational displacements θx, θy.

  The 5-degree-of-freedom rotor displacement is fed back, and deviation signals between the 5-degree-of-freedom rotor displacement and the radial direction translational displacement commands Xc and Yc, the axial direction translational displacement command Zc, and the radial direction rotational displacement commands θxc and θyc are output in the position control loop. Input to the PI controller 16. The PI controller 16 calculates and outputs a 5-degree-of-freedom speed command for the magnetic bearing based on the input deviation signal.

The 5-degree-of-freedom rotor displacement output from the rotor displacement calculator 12 is further differentiated by the differentiator 18 and converted into a 5-degree-of-freedom rotor speed, and the 5-degree-of-freedom speed command and the differentiator that are the outputs of the PI controller 16. A speed deviation signal in the speed control loop is obtained from the rotor speed of 5 degrees of freedom which is 18 outputs. This speed deviation signal is input to the P controller 17 in the speed control loop, outputs the signal subjected to the speed control loop gain K _D bearing force command Fx with respect to the magnetic bearing, Fy, Fz and radial bearing moment command Nx, as Ny To do.

  The gap length calculator 13 calculates gap lengths G1, G2,..., Gn in each of the n electromagnets constituting the magnetic bearing based on the 5-degree-of-freedom rotor displacement output from the rotor displacement calculator 12. In the power distributor 14, the bearing force output from the P controller 17 in the speed control loop at the bearing electromagnet gap length Gi (i = 1, 2,..., N) output from the gap length calculator 13. Supply currents I1, I2,..., In are distributed and supplied to each of the n electromagnets according to the commands Fx, Fy, Fz and the radial bearing moment commands Nx, Ny.

  However, in FIG. 5, for the sake of simplicity, the feedback loop of the axial translational motion and the radial rotational motion is not shown.

  By such an operation of the bearing control system 10, it is possible to control the rotor levitation position so as to coincide with the radial translational displacement commands Xc and Yc, the axial translational displacement command Zc, and the radial rotational displacement commands θxc and θyc. In addition, since the bearing control system 10 is a double loop control of a position control loop and a speed control loop, the position control closed loop gain characteristic is flatter than the single feedback loop PID controller shown in FIG. Thus, the bearing control system 10 can be designed so that the rotor swing amount in the servo resonance frequency region of the magnetic bearing and the disturbance of the magnetic bearing device can be suppressed.

  Even if the phase advance amount in the fixed coordinate converter / phase converter 25 is set to zero by the action of the translational displacement command control system 20, the axial direction rotor rotational speed is the position of the bearing control system 10 as in the first embodiment. In the case of being within the control band, the rotor center-of-gravity position G is positioned on the rotating shaft of the magnetic bearing, so that the disturbance force due to the rotor unbalance can be reduced.

  However, conventionally, the phase advance amount in the fixed coordinate converter / phase converter 25 is set to zero, and the axial direction rotor rotation speed is maintained while the phase advance amount in the fixed coordinate converter / phase converter 25 is held at zero value. Is increased to the servo resonance frequency range, the rotor geometric center position S is obtained with respect to the rotational coordinate system expressions Xcr and Ycr of the radial translational displacement command represented by the vector 32 as shown in FIG. The bearing control system 10 moves on the rotational coordinate system along the vector 34 rotated in the direction opposite to the rotor rotation direction 33 by a phase angle corresponding to the delay of the position control closed loop phase characteristic. As a result, the rotor center-of-gravity position G and the rotor geometric center position S after a lapse of a predetermined time are arranged as shown in FIG. 6B, and the whirling force and radial direction bearing force command caused by the rotor unbalance are obtained. As a result of the rotational coordinate system representations being vectors 30 ′ and 31 ′, the rotational coordinate system representation vector 31 of the radial bearing force command rotates in the same direction as the rotor rotational direction 33, and the rotor center-of-gravity position G, the magnetic bearing rotational axis, Therefore, the disturbance force due to the rotor unbalance cannot be reduced.

  Thus, in the low disturbance control device of the second embodiment, in the translational displacement command control system 20, the radial direction bearing force commands Fx and Fy, the axial direction rotor rotation angle θz, and the position control closed loop phase characteristic of the bearing control system 10 are used. Based on this, the rotor center-of-gravity position G is located at the origin of the rotational coordinate system regardless of the axial direction rotor rotational speed in any frequency region within the position control band of the bearing control system 10, the servo resonance frequency region, and the position control band. The radial translation displacement commands Xc and Yc are controlled.

  The radial direction bearing force commands Fx and Fy output from the P controller 17 are rotated by the rotation coordinate converter 21 based on the axial direction rotor rotation angle θz and the rotation coordinate system shown in the above formulas (1) and (2). The expressions Fxr and Fyr are converted. In the rotational coordinate system representations Fxr and Fyr of the radial bearing force command, only the rotor rotation synchronization component is extracted by the LPF 22 in which the low pass frequency band is set to a narrow band of about 1 Hz. The output of the LPF 22 is represented by a vector 31 in FIG. 6C. This is integrated by the integrator 23, and the signals Xcr ′ and Ycr ′ obtained by the integration are input to the fixed coordinate converter / phase converter 25. The

  In the fixed coordinate converter / phase converter 25, the outputs Xcr ′ and Ycr ′ of the integrator 23 are converted into a fixed coordinate system expression using the axial direction rotor rotation angle θz. At this time, the position of the bearing control system 10 is changed. Considering the control closed-loop phase characteristics, a signal converted into a fixed coordinate system expression after a predetermined phase amount α is advanced according to the axial direction rotor rotational speed as shown in the following equations (5) and (6), It outputs to the bearing control system 10 as radial direction translational displacement command Xc, Yc.

  The rotational coordinate system representations Xcr and Ycr of the radial translational displacement commands Xc and Yc are represented by a vector 32 in FIG. 6C, and the rotor geometric center position S is controlled by the position control of the bearing control system 10 with respect to the vector 32. Since it moves on the rotating coordinate system along the vector 34 rotated in the direction opposite to the rotor rotation direction 33 by the phase angle corresponding to the delay of the closed loop phase characteristic, in the steady state, as shown in FIG. The position G is positioned at the origin of the rotating coordinate system.

  As a result, both the run-out force 30 caused by the rotor static imbalance and the rotational coordinate system representation 31 of the radial bearing force command converge to the zero vector, and therefore the radial bearing force acting on the rotor and the radial acting on the stator. As a result of the reduction in both directional bearing force reactions, the level of disturbance forces due to rotor static imbalance is reduced.

  Here, when the phase advance amount α in the fixed coordinate converter / phase converter 25 is set to an excessive value as shown in FIG. 6E, the moving direction vector 34 of the rotor geometric center position S is expressed in the radial direction. The arrangement is such that the bearing force command vector 31 is rotated by a predetermined phase angle in the rotor rotation direction 33.

  As a result, the rotor center-of-gravity position G and the rotor geometric center position S after a lapse of a predetermined time are arranged as shown in FIG. 6 (f), and the whirling force and radial direction bearing force command caused by the rotor unbalance are obtained. As a result of the rotational coordinate system representations being vectors represented by 30 ′ and 31 ′, the rotational coordinate system representation vector 31 of the radial bearing force command rotates in the direction opposite to the rotor rotational direction 33.

  That is, the rotational coordinate system expression vector 31 of the radial bearing force command is obtained when the phase advance amount α in the fixed coordinate converter / phase converter 25 is smaller than the optimum value (FIGS. 6A and 6B). When rotating in the same direction as the rotor rotation direction 33 and larger than the optimum value (FIGS. 6 (e) and (f)), it rotates in the opposite direction to the rotor rotation direction 33, and in the case of the optimum value (FIG. 6 (c) ), (D)) converges to a zero vector without changing the direction of the vector.

  Accordingly, the phase advance amount α in the fixed coordinate converter / phase converter 25 converges to the zero vector without rotating the rotational coordinate system expression vector 31 of the radial bearing force command at any axial rotor rotational speed. By setting to such a value, the axial direction rotor rotational speed is caused by the rotor static imbalance regardless of the frequency range within the position control band, the servo resonance frequency range, and the position control band of the bearing control system 10. The swinging force 30 and the rotational coordinate system representation 31 of the radial bearing force command can be converged to the zero vector, and both the radial bearing force acting on the rotor and the radial bearing force reaction acting on the stator are reduced. , The level of disturbance force due to rotor unbalance decreases in the entire frequency range including the servo resonance frequency range. So as to.

  As described above, the low disturbance control device according to the second embodiment allows the axial direction rotor rotational speed to be in any frequency region within the position control band, the servo resonance frequency range, and the position control band of the bearing control system 10. The rotor center-of-gravity position G is positioned on the rotating shaft of the magnetic bearing, and the disturbance force caused by the rotor unbalance can be reduced in the entire frequency region including the servo resonance frequency region of the magnetic bearing.

  Further, since the LPF 22 in the translational displacement command control system 20 extracts only the rotor rotation synchronization component, signal components belonging to a frequency region other than the rotor rotation synchronization component can be easily removed.

  Furthermore, the bearing control system 10 is configured as a double loop control of a position control loop and a speed control loop, and the bearing control system 10 is designed so that the position control loop gain characteristic becomes flat, so that in the servo resonance frequency region of the magnetic bearing. It is possible to further suppress the amount of rotor swing and disturbance of the magnetic bearing device.

Embodiment 3 FIG.
FIG. 7 is a block diagram for explaining the low disturbance control device according to the third embodiment of the present invention, and FIG. 8 is a Bode diagram showing the closed-loop gain characteristics, and FIGS. 9, 10, and 11 are used. These are rotor sectional drawings for demonstrating the low disturbance control apparatus of this Embodiment 3, In FIG. 7, what attached | subjected the code | symbol same as FIG.3 and FIG.5 shows the same part or an equivalent part. 9, 10, and 11, the same reference numerals as those in FIGS. 2, 4, and 6 denote the same or corresponding parts.

  As shown in FIG. 7, the low disturbance control device according to the third embodiment calculates a radial rotational displacement command for the bearing control system 10 from the radial bearing moment commands Nx and Ny in the bearing control system 10. A rotational displacement command control system 40 for outputting is provided.

  The rotational displacement command control system 40 converts the radial bearing moment commands Nx, Ny in the bearing control system 10 into rotational coordinate system representations Nxr, Nyr fixed to the rotor using the axial rotor rotational angle θz. LPF (low-pass filter), which extracts only the rotor rotation synchronization component of the bearing moment command, by setting the low pass frequency band to a narrow band of about 1 Hz with respect to the rotating coordinate system representation Nxr, Nyr of the bearing 41 Filter) 42, integrator 43 that integrates the outputs of LPF 42 and outputs radial rotational displacement signals θxcr ′ and θycr ′, converts signals θxcr ′ and θycr ′ into a fixed coordinate system representation, and In consideration of the phase characteristics, a signal obtained by advancing a predetermined phase amount in accordance with the axial rotor rotational speed is transmitted to the bearing control system 10. A fixed coordinate converter / phase converter 45 that outputs radial rotational displacement commands θxc and θyc is provided.

Further, in FIG. 8, the position control loop gain characteristic 50 of the bearing control system 10 constructed in double loop control, the speed control loop gain characteristic of the bearing control system 10 51, position control frequency band f _p, speed control frequency The band is f _D , the axial rotor rotational speed is f, and the speed control loop gain switching threshold is f ₁ .

  9A and 9B show a magnetic bearing device of a cylindrical rotor (FIG. 1), and the rotational displacement command control system 40 is applied when the axial direction rotor rotational speed is within the position control band of the bearing control system 10. 9 (c) and 9 (d) show a state after sufficient time has elapsed after applying the rotational displacement command control system 40, and FIGS. 10 (a) and 10 (b) show a disk-shaped rotor (FIG. 2). ) In the case where the axial direction rotor rotational speed is within the position control band of the bearing control system 10, immediately after applying the rotational displacement command control system 40, FIGS. 10C and 10D show the rotation. It shows after a sufficient time has elapsed after applying the displacement command control system 40.

  Further, in FIGS. 9 to 11, when the axial rotor inertia main shaft is P, the fixed point on the axial rotor inertia main shaft P is a, the rotor is divided into two parts and each part is replaced with a mass point, The acting centrifugal force is F, the swinging moment due to the rotor dynamic imbalance is 60, and the moment having the rotational coordinate system expression Nxr, Nyr of the radial bearing moment command output from the rotational coordinate converter 41 as an element is 61. The rotational coordinate system representation of the radial direction rotational displacement command is 62.

  11 (a), 11 (c) and 11 (e) show the amount of phase advance in the fixed coordinate converter / phase converter 45 when the axial rotor rotational speed is increased to the servo resonance frequency range of the magnetic bearing or higher. FIGS. 11 (b), (d) and (f) show FIGS. 11 (a), 11 (c) and (f), respectively, immediately after applying the rotational displacement command control system 40 as a zero value, an optimum value and an excessive value. 7 is a radial cross-sectional view of the rotor after a sufficient time has elapsed after applying the rotational displacement command control system 40 in e). FIG.

  Further, in FIG. 11, in the fixed coordinate converter / phase converter 45, a predetermined phase amount advanced according to the axial direction rotor rotational speed is β, the rotor rotational direction is 63, and the rotational direction vector of the axial direction rotor inertial main axis P is 64.

Next, the operation will be described. In FIG. 7, for the sake of simplicity, the feedback loop of the radial translation and the axial translation is not shown, but the operation of the bearing control system 10 is the same as that of the second embodiment. At this time, the position control loop gain characteristic 50 and a speed control loop gain characteristic 51 of the bearing control system 10 is as shown in FIG. 8 (a), the speed control frequency band f _D than the position control frequency band f _P The bearing control system 10 is designed to be sufficiently high. By adopting such a design, the position control loop gain characteristic becomes flat, and the rotor swing amount in the servo resonance frequency region (position control frequency band f _P ) of the magnetic bearing and the disturbance generated in the magnetic bearing device can be suppressed. On the other hand, however, the disturbance generated by the magnetic bearing device in the speed control system gain intersection frequency range (speed control frequency band f _D ) tends to increase somewhat.

Therefore, in the low disturbance control device according to the third embodiment, when the speed control loop gain switching threshold f ₁ is set and the axial direction rotor rotational speed f is lower than f ₁ , FIG. As described above, when the speed control loop gain K _D of the bearing control system 10 is increased so that the rotor rotational speed f <f ₁ <speed control frequency band f _D , and the axial direction rotor rotational speed f is higher than f _1. As shown in FIG. 8B, the speed control loop gain K _D of the bearing control system 10 is decreased so that the speed control frequency band f _D <f ₁ <rotor rotational speed f is satisfied, thereby speed control. frequency band f _D is configured not to belong to the vicinity of the axial rotor rotational speed f, without impairing the stability of the bearing control system 10, the speed control system gain crossover frequency range (speed control frequency band it is possible to suppress the occurrence disturbance of the magnetic bearing apparatus in f _D).

  By such an operation of the bearing control system 10, it is possible to control the rotor levitation position so as to coincide with the radial translational displacement commands Xc and Yc, the axial translational displacement command Zc, and the radial rotational displacement commands θxc and θyc. In addition, since the bearing control system 10 is a double loop control of a position control loop and a speed control loop, the position control closed loop gain characteristic is flatter than the single feedback loop PID controller shown in FIG. Thus, the bearing control system 10 can be designed so that the rotor swing amount in the servo resonance frequency region of the magnetic bearing and the disturbance of the magnetic bearing device can be suppressed.

In addition, by changing the speed control loop gain K _D according to the rotor rotational speed f so that the speed control frequency band f _D does not belong to the vicinity of the axial direction rotor rotational speed f in the bearing control system 10, Without impairing the stability of the bearing control system 10, it is possible to further suppress the disturbance of the magnetic bearing device in the speed control system gain intersection frequency range.

  In the conventional magnetic bearing control device, the radial direction rotational displacement commands θxc and θyc for the bearing control system 10 are always zero, and therefore the rotor cross section when the axial direction rotor rotational speed is lower than the position control band of the bearing control system 10. The figure is ideally shown in FIGS. 9 (a) and 9 (b) for a cylindrical rotor (FIG. 1), and shown in FIGS. 10 (a) and 10 (b) for a disk-like rotor (FIG. 2). It will be true. That is, when viewed from the rotational coordinate system Xr-Yr perpendicular to the rotor rotation axis (Z axis) and fixed to the rotor, the rotation in the radial direction calculated by the rotor displacement calculator 12 is two degrees of freedom. The displacements θx and θy are held at zero values, and the axial direction rotor inertia main shaft P is inclined with respect to the rotor rotation axis (Z axis) by an angle corresponding to the rotor motion imbalance. However, in FIGS. 9 and 10, for the sake of simplicity, the case where the axial direction rotor inertia main axis P is located in the Zr-Xr plane is described.

  At this time, when the rotor is divided into two parts and each part is replaced with a mass point, the centrifugal force F acting on each mass point is as shown in FIG. 9 (a) and FIG. 10 (a). The swinging moment 60 caused by the dynamic imbalance acts on. In order to maintain the rotor floating position, that is, the rotational displacement θx, θy in the radial direction with two degrees of freedom under the action of the swinging moment 60 at a zero value, the moment having the rotational coordinate system expression Nxr, Nyr of the radial direction bearing moment command as an element. 61 has a reverse polarity to the swinging moment 60. At this time, the reaction of the radial bearing moment acting on the rotor acts on the stator, and this becomes the main factor of vibration of the moment transmitted to the housing of the magnetic bearing device, that is, disturbance.

  Thus, in the low disturbance control device of the third embodiment, in the rotational displacement command control system 40, first, the rotor inertia main shaft P is based on the radial direction bearing moment commands Nx, Ny and the axial direction rotor rotation angle θz. Are controlled so as to be parallel to the rotation axis of the magnetic bearing so that the radial rotational displacement commands θxc and θyc are controlled.

  The radial bearing moment commands Nx and Ny output from the P controller 17 are expressed in the rotational coordinate system as shown in the following equations (7) and (8) by the rotational coordinate converter 41 based on the axial rotor rotational angle θz. Converted to Nxr and Nyr.

  In the rotational coordinate system representations Nxr and Nyr of the radial bearing moment command, only the rotor rotation synchronization component is extracted by the LPF 42 in which the low pass frequency band is set to a narrow band of about 1 Hz. The output of the LPF 42 is represented by a moment 61 in FIGS. 9A and 9B and FIGS. 10A and 10B, and this moment 61 has the same polarity (FIG. 9B) in the cylindrical rotor. In the disk-shaped rotor, as a result of integration in the integrator 43 with the reverse polarity (FIG. 10B), the rotational coordinate system representations θxcr ′ and θycr ′ of the radial direction rotational displacement command represented by the rotation vector 62 are integrated in the integrator 43. Is output from. In the fixed coordinate converter / phase converter 45, when the axial rotor rotational speed is within the position control band of the bearing control system 10, the outputs θxcr ′ and θycr ′ of the integrator 43 are set to the axial rotor rotational angle θz. By using them, they are converted into fixed coordinate system expressions θxc and θyc as in the following equations (9) and (10), and output to the bearing control system 10.

  The bearing control system 10 controls the rotor floating position so as to follow the radial direction rotational displacement commands θxc and θyc thus determined, whereby the axial direction rotor inertia main shaft P follows the rotational vector 62 on the rotational coordinate system. In a steady state, the rotor inertia main shaft P is parallel to the magnetic bearing central axis as shown in FIGS. 9C, 9D, 10C, and 10D. Thus, the rotational coordinate system representation 61 of the run-out moment 60 and the radial bearing moment command due to the rotor dynamic imbalance converges to zero values, and thus the radial bearing moment acting on the rotor and the radial direction acting on the stator. As a result of both bearing moment reactions being reduced, the level of disturbance moments due to rotor dynamic imbalance is reduced.

  As described above, in the rotational motion in the radial direction, the swinging moment 60 caused by the rotor dynamic imbalance, and hence the polarity of the radial bearing moment command 61, is reversed by the magnitude relationship between the axial inertia moment and the radial inertia moment of the rotor. To do. Accordingly, when the polarity of the integral operation executed by the integrator 43 to calculate the rotational coordinate system representation 62 of the radial direction rotational displacement command is radial moment of inertia> axial moment of inertia (cylindrical rotor), the polarity is Note that if the moment of inertia in the axial direction is greater than the moment of inertia in the radial direction (disk-shaped rotor), the polarity is reversed.

  As described above, due to the action of the rotational displacement command control system 40, the axial direction rotor rotational speed is within the position control band of the bearing control system 10 even if the phase advance amount in the fixed coordinate converter / phase converter 45 is zero. In this case, the axial direction rotor inertia main shaft P is parallel to the magnetic bearing rotating shaft, and the disturbance moment caused by rotor dynamic imbalance can be reduced.

  However, when the axial direction rotor rotation speed is increased to the servo resonance frequency range while the phase advance amount in the fixed coordinate converter / phase converter 45 is kept at zero, the rotor inertia main axis P is shown in FIG. Thus, with respect to the rotational coordinate system representation θxcr ′, θycr ′ of the radial direction rotational displacement command represented by the rotation vector 62, the rotor rotational direction is equal to the phase angle corresponding to the delay of the position control closed loop phase characteristic of the bearing control system 10. According to the rotation vector 64 rotated in the opposite direction to 63, the rotation coordinate system is rotated. As a result, the fixed points a on the rotor inertia main shaft P after a predetermined time have passed are arranged as shown in FIG. 11B, and the rotational coordinates of the swinging moment and the radial bearing moment command caused by the rotor dynamic imbalance. As a result of the system representations being 60 ′ and 61 ′, the rotational coordinate system representation 61 of the radial bearing moment command rotates in the same direction as the rotor rotational direction 63, and the rotor inertia main shaft P and the magnetic bearing rotational shaft Since the angle with the angle does not converge to zero, the disturbance moment due to rotor dynamic imbalance cannot be reduced.

  Therefore, in the low disturbance control device according to the third embodiment, in the rotational displacement command control system 40, the axial direction rotor rotational speed is controlled based on the position control closed loop phase characteristic of the bearing control system 10 according to the position control of the bearing control system 10. The phase advance amount in the fixed coordinate converter / phase converter 45 is set so that the rotor inertial main shaft P is parallel to the magnetic bearing rotation axis in any frequency region outside the band, the servo resonance frequency region, and the position control band. It adjusts and controls radial direction rotational displacement commands θxc and θyc.

  The fixed coordinate converter / phase converter 45 converts the outputs θxcr ′ and θycr ′ of the integrator 43 into a fixed coordinate system expression using the axial direction rotor rotation angle θz. At this time, the position of the bearing control system 10 is changed. Considering the control closed-loop phase characteristics, a signal converted into a fixed coordinate system expression after a predetermined phase amount β is advanced according to the axial direction rotor rotational speed as shown in the following equations (11) and (12), Output to the bearing control system 10 as radial direction rotational displacement commands θxc, θyc.

  The rotational coordinate system representations θxcr and θycr of the radial direction rotational displacement commands θxc and θyc are represented by the rotation vector 62 in FIG. 11C, and the rotor inertia main axis P is the position of the bearing control system 10 with respect to the rotation vector 62. As shown in FIG. 11 (d), in the steady state, the rotation is performed on the rotating coordinate system according to the rotation vector 64 rotated in the direction opposite to the rotor rotation direction 63 by the phase angle corresponding to the delay of the control closed loop phase characteristic. The rotor inertia main shaft P is parallel to the magnetic bearing rotating shaft. Thus, the rotational coordinate system representation 61 of the run-out moment 60 and the radial bearing moment command due to the rotor dynamic imbalance converges to zero values, and thus the radial bearing moment acting on the rotor and the radial direction acting on the stator. As a result of both bearing moment reactions being reduced, the level of disturbance moments due to rotor dynamic imbalance is reduced.

  Here, when the phase advance amount β in the fixed coordinate converter / phase converter 45 is set to an excessive value as shown in FIG. 11 (e), the rotational direction vector 64 of the rotor inertia spindle P is represented by a radial bearing moment. The arrangement is rotated by a predetermined phase angle in the rotor rotation direction 63 with respect to the command vector 61. As a result, the fixed points a on the rotor inertia main shaft P after a predetermined time have elapsed are arranged as shown in FIG. 11 (f), and the rotation moment and radial direction bearing moment command due to rotor dynamic imbalance are rotated. As a result of the coordinate system representations being moments represented by 60 ′ and 61 ′, the rotational coordinate system representation 61 of the radial bearing moment command rotates in the direction opposite to the rotor rotational direction 63.

  In other words, the rotational coordinate system representation 61 of the radial bearing moment command indicates that the rotor is in the case where the phase advance amount β in the fixed coordinate converter / phase converter 45 is smaller than the optimum value (FIGS. 11A and 11B). When rotating in the same direction as the rotation direction 63 and larger than the optimum value (FIGS. 11E and 11F), the rotation is in the direction opposite to the rotor rotation direction 63, and the optimum value is obtained (FIG. 11C). , (D)) converges to a zero value without changing the direction. Accordingly, the phase advance amount β in the fixed coordinate converter / phase converter 45 is converged to a zero value without rotating the rotational coordinate system representation 61 of the radial bearing moment command at any axial rotor rotational speed. By setting the value to a proper value, the rotor inertia main shaft P is located at the center of the magnetic bearing regardless of the axial direction rotor rotational speed in any position within the position control band of the bearing control system 10, the servo resonance frequency area, and the position control band. By being parallel to the shaft, it is possible to converge both the run-out moment 60 caused by rotor dynamic imbalance and the rotational coordinate system representation 61 of the radial bearing moment command to zero values. As a result, the radial bearing moment acting on the rotor and the radial bearing moment reaction acting on the stator are both reduced, so that the level of disturbance moment caused by rotor dynamic imbalance is in the entire frequency range including the servo resonance frequency range. It begins to decline.

  As described above, by the low disturbance control device of the third embodiment, the axial direction rotor rotational speed is in any frequency region within the position control band, the servo resonance frequency range, and the position control band of the bearing control system 10. The rotor inertia main shaft is parallel to the rotating shaft of the magnetic bearing, and the disturbance moment due to rotor dynamic imbalance can be reduced in the entire frequency region including the servo resonance frequency region of the magnetic bearing.

  Further, since the LPF 42 in the rotational displacement command control system 40 extracts only the rotor rotation synchronization component, signal components belonging to a frequency region other than the rotor rotation synchronization component can be easily removed.

  Furthermore, the bearing control system 10 is configured as a double loop control of a position control loop and a speed control loop, and the bearing control system 10 is designed so that the position control loop gain characteristic becomes flat, so that in the servo resonance frequency region of the magnetic bearing. It is possible to further suppress the amount of rotor swing and disturbance of the magnetic bearing device.

In addition, as the speed control bandwidth 51 in the bearing control system 10 that is not belonging to the vicinity of the axial direction the rotor rotational speed f, by varying the speed control loop gain K _D according to the rotor rotational speed f, bearing control Without impairing the stability of the system 10, it is possible to further suppress the disturbance of the magnetic bearing device in the speed control system gain intersection frequency range.

Further, in the third embodiment, although the switching threshold of the speed control loop gain K _D of been described is a single frequency f _1, be the switching threshold is to have a predetermined hysteresis width around the f ₁ Good. In this case, in addition to the same effects as in the third embodiment, noise is further superimposed on the rotor rotational speed signal f, or the rotor rotational speed f is close to the speed control loop gain switching threshold f ₁ . in the case of increasing or decreasing, it is possible to realize the switching of a more stable speed control loop gain K _D.

Embodiment 4 FIG.
FIG. 12 is a block diagram for explaining the fourth embodiment of the low disturbance control device according to the present invention, where the same reference numerals as those in FIGS. 3 and 5 designate the same or corresponding parts. .

  Next, the operation will be described. In FIG. 12, for the sake of simplicity, the feedback loop of the axial translational motion and the radial rotational motion is not shown, but the operation of the bearing control system 10 is the same as that of the third embodiment except for the rotor displacement calculator 12. is there. The operation of the translational displacement command control system 20 is the same as that in the second embodiment.

  In the fourth embodiment, the rotor displacement calculator 12 uses, for example, the geometry of the rotor 1 for the rotor displacement information Si (i = 1, 2,..., N) output from the electromagnet / rotor / displacement detecting means 11. Using the rotor displacement information Si0 (i = 1, 2,..., N) and the conversion coefficient γ when located at the center, the case where the rotor as shown in the following equation (13) is located at the geometric center is used as a reference. It is converted into a gap length variation ΔXi (i = 1, 2,..., N) between the displacement detection means 3 and the rotor 1.

  Next, with respect to the gap length variation ΔXi (i = 1, 2,..., N), the rotor geometry and the arrangement of the displacement detection means 3 are taken into consideration, as shown in the following equation (14). A 5-degree-of-freedom rotor displacement consisting of 3-degree-of-freedom translational displacements X, Y, Z and radial direction 2-degree-of-freedom rotational displacements θx, θy is calculated.

In the above equation (14), A is a 5 × n conversion matrix.
Under the premise that the displacement detection surface of the rotor 1 targeted by the displacement detection means 3 is a perfect circle and the displacement detection means 3 is arranged on a concentric circle centered on the rotor rotation axis, the rotor 1 The rotor displacement information Si0 (i = 1, 2,..., N) when located at the geometric center all have the same value (DC) regardless of the axial direction rotor rotation angle θz. Normally, the rotor displacement information Si0 (i = 1, 2,..., N) when the rotor is located at the geometric center is assumed to be satisfied by the above assumption, and is all the same DC value independently of the axial direction rotor rotation angle θz. In this case, in the case where the rotor displacement detection surface is distorted with respect to a perfect circle, or the arrangement of the displacement detection means 3 is not on a concentric circle centered on the rotor rotation axis, An error between the output of the rotor displacement calculator 12 and the true rotor displacement tends to increase. At this time, the bearing control system 10 calculates a bearing force command, a radial direction bearing moment command and a bearing electromagnet gap length based on the rotor 5 degree-of-freedom displacement including an error, and this bearing force command, radial direction bearing moment command and bearing Based on the electromagnet gap length, the power distributor 14 distributes and supplies the supply current Ii (i = 1, 2,..., N) to the bearing electromagnet.

  Accordingly, as a result of the output of the rotor displacement calculator 12 including an error, the error between the bearing force command and the radial bearing moment command and the true bearing force and the true radial bearing moment acting on the rotor is increased, and the translation is performed. In the displacement command control system 20 and the rotational displacement command control system 40, even if the radial direction bearing force command and the radial direction bearing moment command are controlled to be zero vectors, it is caused by disturbance force and dynamic imbalance caused by static unbalance. The disturbance moment to be generated continues to be generated from the magnetic bearing device with a predetermined magnitude.

  Therefore, in the low disturbance control device of the fourth embodiment, the axial rotor rotation angle with respect to the rotor displacement calculator 12 is reduced so that an error between the output of the rotor displacement calculator 12 and the true rotor displacement is reduced. A correction function based on θz is introduced. As described above, the factors that include errors in the output of the rotor displacement calculator 12 include the distortion of the rotor displacement detection surface with respect to the true circle and the deviation of the displacement detection means 3 from the concentric circle centered on the rotor rotation axis. For the rotor displacement information Si0 (i = 1, 2,..., N) when the rotor 1 is located at the geometric center, the former is an AC component error that varies according to the axial direction rotor rotation angle θz, and the latter is Each of the displacement detection means 3 acts as a DC component error that varies individually.

  Therefore, a correction function based on the axial direction rotor rotation angle θz is applied to the rotor displacement information Si0 (i = 1, 2,..., N) at the geometric center so as to remove the AC component error and the DC component error. Then, the gap length variation ΔXi (i = 1, 2,..., N) is calculated as shown in the following equation (15).

Si0 (θz) (i = 1, 2,..., N) in the above formula (15) is the statics when the rotor is statically levitated without rotating around the rotation axis, and the bearing electromagnet supply current measurement at this time It can be derived based on the value. In the block diagram shown in FIG. 12, the translational displacement command control system 20 is stopped, and the radial translational displacement commands Xc and Yc, the axial translational displacement command Zc, and the radial rotational displacement commands θxc and θyc with respect to the bearing control system 10. When all the zero values are input, the steady deviation with respect to the command becomes zero due to the action of the integrator in the PI controller 16 if the rotor is still floating without rotating, which is the output of the rotor displacement calculator 12. The 5-degree-of-freedom rotor displacements X, Y, Z, θx, and θy are all held at zero values. At this time, true three-degree-of-freedom translational displacement of the rotor center of gravity is Xt, Yt, Zt, true radial two-degree-of-freedom rotational displacement of the rotor inertial spindle P is θxt, θyt, rotor mass is M, gravity acceleration is g, magnetic When the true three-degree-of-freedom bearing force acting on the rotor by the bearing is Fxt, Fyt, Fzt, and the true radial two-degree-of-freedom bearing moment is Nxt, Nyt, in the fixed coordinate system shown in FIG. , (17) holds.

  At this time, if the true magnetic attractive force generated by the bearing electromagnet is Fit (i = 1, 2,..., N), the true bearing forces Fxt, Fyt, Fzt, the true radial bearing moments Nxt, Nyt And the true magnetic attraction force Fit (i = 1, 2,..., N) is expressed by the following equation (18), where B is a 5 × n conversion matrix.

  In addition, the true magnetic attractive force Fit (i = 1, 2,..., N) in the bearing electromagnet is the measured supply current value for each bearing electromagnet Ii (i = 1, 2,..., N), The true gap length with the rotor suction surface is expressed by the following equation (19), where Git (i = 1, 2,..., N) and the conversion coefficient are k.

  Further, the true bearing electromagnet gap length Git (i = 1, 2,..., N) is equal to Gi0 (i = 1, 2,..., N), C when the rotor is located at the geometric center. Is given by the following equation (20) as an n × 5 conversion matrix.

  The above formulas (18) to (20) are substituted into the above formulas (16) and (17), and the bearing electromagnet supply current measurement value Ii (i = 1, i.e., when statically levitated at a predetermined axial direction rotor rotation angle θz. 2,..., N) is applied to obtain a simultaneous simultaneous equation relating to true 5-degree-of-freedom rotor displacement Xt, Yt, Zt, θxt, θyt at the rotation angle θz. The nonlinear simultaneous equations can be derived numerically by a calculation method such as Newton's method, and at this time, the 5-degree-of-freedom rotor displacement X, Y, Z, θx, θy, which is the output of the rotor displacement calculator 12, is Since all of them are held at zero values, this numerical solution (true five-degree-of-freedom rotor displacement Xt, Yt, Zt, θxt, θyt) matches the output error in the rotor displacement calculator 12.

  By the above procedure, it is possible to derive the output error of the rotor displacement calculator 12 at a predetermined rotation angle θz, and thus Si0 (θz) (i = 1, 2,..., N) in the above equation (15). Then, by applying the gap length variation ΔXi (i = 1, 2,..., N) obtained by the above equation (15) to the above equation (14), the output of the rotor displacement calculator 12 and the true value The error with the rotor displacement can be reduced, and therefore the error between the bearing force command and the radial bearing moment command in the bearing control system 10 and the true bearing force and the true radial bearing moment acting on the rotor can be reduced. This can reduce the disturbance of the magnetic bearing device.

  Thus, with the low disturbance control device according to the fourth embodiment of the present invention, the axial direction rotor rotational speed is in any frequency region within the position control band of the bearing control system 10, the servo resonance frequency region, and outside the position control band. Even in this case, the rotor center-of-gravity position G is positioned on the rotating shaft of the magnetic bearing, and the disturbance force caused by the rotor static imbalance can be reduced in the entire frequency region including the servo resonance frequency region of the magnetic bearing. it can.

  Further, since the LPF 22 in the translational displacement command control system 20 extracts only the rotor rotation synchronization component, signal components belonging to a frequency region other than the rotor rotation synchronization component can be easily removed.

Furthermore, the bearing control system 10 is configured as a double loop control of a position control loop and a speed control loop, and the bearing control system 10 is designed so that the position control loop gain characteristic becomes flat, so that in the servo resonance frequency region of the magnetic bearing. In addition to being able to further suppress the amount of rotor swing and disturbance generated by the magnetic bearing device, the rotor is controlled so that the speed control band 51 does not belong to the vicinity of the axial rotor rotational speed f in the bearing control system 10. by varying the speed control loop gain K _D according to the rotational speed f, without impairing the stability of the bearing control system 10, achieve a further reduction of generation disturbance of the magnetic bearing apparatus in the speed control system gain crossover frequency range be able to.

  In addition, by reducing an error between the output of the rotor displacement calculator 12 and the true rotor displacement, the bearing force command and the radial bearing moment command in the bearing control system 10, the true bearing force acting on the rotor, and The error from the true radial bearing moment is reduced, and the disturbance generated in the magnetic bearing device can be further reduced.

Embodiment 5 FIG.
FIG. 13 is a block diagram for explaining the fifth embodiment of the low disturbance control device according to the present invention, and FIG. 14 is an arrangement of displacement detecting means and rotor displacement detecting surfaces in data measurement for deriving a correction function. In FIG. 13, the same reference numerals as those in FIGS. 3 and 5 designate the same or corresponding parts.

  As shown in FIG. 14, the low disturbance control device according to the fifth embodiment has an arbitrary displacement detection means 70 for detecting the rotor displacement detection direction 71, and a rotor displacement in the rotor displacement detection direction 71 by the displacement detection means 70. Is provided with a rotor displacement detection surface 72 and a rotor rotation axis (Z-axis) 73.

  Next, the operation will be described. In FIG. 13, for the sake of simplicity, the feedback loop of the axial translational motion and the radial rotational motion is not shown, but the operation of the bearing control system 10 is performed except for the rotor displacement calculator 12 and the gap length calculator 13. This is the same as Form 3. The operation of the translational displacement command control system 20 is the same as that in the second embodiment.

  In the fifth embodiment, the rotor displacement calculator 12 rotates the rotor in the axial direction with respect to the rotor displacement information Si (i = 1, 2,..., N) output from the electromagnet / rotor / displacement detecting means 11. Using the rotor displacement information Si0 (i = 1, 2,..., N) and the conversion coefficient γ at the rotor geometric center with the correction function based on the angle θz and the conversion coefficient γ, the displacement detection means 70 and the rotor are expressed by the above equation (15). The gap length variation amount ΔXi (i = 1, 2,..., N) is calculated, and then the gap length variation amount ΔXi (i = 1, 2,..., N) is used to calculate 5 degrees according to the above equation (14). By calculating the degree of rotor displacement X, Y, Z, θx, θy, the error between the output of the rotor displacement calculator 12 and the true rotor displacement can be reduced.

  Further, the gap length calculator 13 uses a bearing electromagnet gap length Gi0 (i = 1, 2,..., N) and an n-row / 5-column conversion matrix C when the rotor is located at the geometric center, to calculate the rotor displacement calculator. From the 5-degree-of-freedom rotor displacements X, Y, Z, θx, and θy that are 12 outputs, the gap length Gi (i = 1, 2,..., N) between the bearing electromagnet and the rotor attraction surface as shown in the following equation (21): ) Is calculated.

  Here, the rotor is positioned at the geometric center under the assumption that the rotor attracting surface targeted by the bearing electromagnet is a perfect circle and the bearing electromagnet is arranged on a concentric circle centered on the rotor rotation axis. The bearing electromagnet gap lengths Gi0 (i = 1, 2,..., N) in this case all have the same DC value without depending on the axial rotor rotation angle θz. In general, Gi0 (i = 1, 2,..., N) is generally assumed to use the same DC value independently of the axial-direction rotor rotation angle θz on the assumption that the above assumption is satisfied. When the surface is distorted with respect to the perfect circle, or when the arrangement of the bearing electromagnet is not on a concentric circle centered on the rotor rotation axis, the output of the gap length calculator 13 and the true bearing electromagnet gap length Shows a tendency for errors to expand. At this time, the power distributor 14 in the bearing control system 10 supplies a supply current Ii (i = 1, 2,) for realizing a bearing force command and a radial bearing moment command based on the bearing electromagnet gap length including an error. ..., n) are distributed and supplied to the bearing electromagnets.

  Therefore, as a result of the output of the gap length calculator 13 including an error, errors between the bearing force command and the radial bearing moment command and the true bearing force and the true radial bearing moment acting on the rotor are expanded, and the translation is performed. In the displacement command control system 20 and the rotational displacement command control system 40, even if the radial direction bearing force command and the radial direction bearing moment command are controlled to be zero vectors, it is caused by disturbance force and dynamic imbalance caused by static unbalance. The disturbance moment to be generated continues to be generated from the magnetic bearing device with a predetermined magnitude.

  Therefore, in the low disturbance control device of the fifth embodiment, the axial direction rotor with respect to the gap length calculator 13 is reduced so that the error between the output of the gap length calculator 13 and the true bearing electromagnet gap length is reduced. A correction function based on the rotation angle θz is introduced. As described above, the factors that include an error in the output of the gap length calculator 13 include distortion of the rotor attracting surface with respect to a perfect circle and deviation of the bearing electromagnet arrangement from a concentric circle around the rotor rotation axis. With respect to the bearing electromagnet gap length Gi0 (i = 1, 2,..., N) at the geometric center, the former is an AC component error that varies according to the axial rotor rotation angle θz, and the latter is individually determined for each bearing electromagnet. It acts as a DC component error that varies.

  Therefore, the correction function based on the axial direction rotor rotation angle θz so as to remove the above-described AC component error and DC component error with respect to the bearing electromagnet gap length Gi0 (i = 1, 2,..., N) at the geometric center. And the bearing electromagnet gap length Gi (i = 1, 2,..., N) is calculated as shown in the following equation (22).

  As described above, in the low disturbance control device of the fifth embodiment, the correction function based on the axial direction rotor rotation angle θz is expressed by the above equation (15) in the rotor displacement calculator 12 and the above equation in the gap length calculator 13. (22), and Si0 (θz) (i = 1, 2,..., N) in the above formula (15) mechanically constrains the rotor by a touchdown bearing for the purpose of protecting the magnetic bearing. Gi0 (θz) (i = 1, 2,..., N) in the above equation (22) is based on the rotor displacement information in the case, and the statics when the rotor is statically levitated without rotating around the rotation axis. It can derive | lead-out based on the bearing electromagnet supply current measured value at this time.

  In general, in a magnetic bearing device, in order to protect the magnetic bearing device by avoiding contact between the bearing electromagnet and the displacement detecting means and the rotor, the rotor is mechanically moved when the rotor is displaced from the geometric center by a predetermined amount. It is equipped with touch-down bearings that can be restrained. Therefore, by using the rotor displacement information when the rotor 1 is mechanically restrained by the touchdown bearing without operating the bearing control system 10, and the rotor 1 is touched down in the rotor displacement detection direction of the displacement detection means, in particular, Rotor displacement information Si0 (i = 1, 2,..., N) at the rotor geometric center can be obtained.

  For example, the relationship between the displacement detection means for measuring the radial translational displacement of the cylindrical rotor (FIG. 1) and the rotor displacement detection surface can be shown as shown in FIG. In the cylindrical rotor rotating around the rotor rotation shaft 73, the rotor side surface becomes the rotor displacement detection surface 72 with respect to the displacement detection means 70 for measuring the radial translational displacement of the rotor. The rotor is mechanically constrained by a touch-down bearing in a direction in which the gap length with the displacement detection means 70 becomes smaller in the rotor displacement detection direction 71 with respect to the rotor displacement detection surface 72 when the rotor is located at the geometric center. The rotor displacement detection surface when the rotor is mechanically constrained by a touch-down bearing in a direction in which the gap length with the displacement detection means 70 becomes larger in the rotor displacement detection direction 71 is 72 ′. Is 72 ″. Usually, the distance between the rotor displacement detection surface 72 and the rotor displacement detection surface 72 ′ and the distance between the rotor displacement detection surface 72 and the rotor displacement detection surface 72 ″ with respect to the rotor displacement detection direction 71 are the same. Based on the average of the rotor displacement information at 72 ′ and the rotor displacement information at the rotor displacement detection surface 72 ″, the rotor displacement information Si0 (i = 1, 2,..., N) at the rotor geometric center (rotor displacement detection surface 72) is obtained. Can be estimated.

  Further, in the rotor having a shape in which the rotor displacement detection surface 72, and hence the rotor displacement detection direction 71 is inclined with respect to the rotor rotation shaft 73 (FIG. 2), the relationship between the displacement detection means and the rotor displacement detection surface is as shown in FIG. ). With respect to the rotor displacement detection surface 72 when the rotor is located at the geometric center, the rotor is arranged in the positive direction in the axial direction (Z-axis direction) and in the direction in which the gap length with the displacement detection means 70 becomes smaller in the radial direction. When the rotor is mechanically restrained by the touchdown bearing, the rotor displacement detection surface is 72 ', the rotor arrangement is positive in the axial direction (Z-axis direction), and the gap length with the displacement detection means 70 is large in the radial direction. When the rotor is mechanically constrained by a touchdown bearing, the rotor displacement detection surface is 72 ″, the rotor arrangement is negative in the axial direction (Z-axis direction), and the gap length with the displacement detection means 70 in the radial direction. When the rotor is mechanically constrained by a touchdown bearing, the rotor displacement detection surface is 72 '' 'and the rotor arrangement is in the axial direction (Z-axis direction). In the negative direction, facing the gap length between the displacement detection means 70 in the radial direction becomes smaller, the rotor displacement detection surface in the case of mechanically constrained by touchdown bearing is a 72 '' ''.

  At this time, the rotor displacement information Si0 (i = 1, 2,..., N) at the time of the rotor geometric center (rotor displacement detection surface 72) is obtained by averaging the rotor displacement information on the rotor displacement detection surfaces 72 ′ to 72 ″ ″. Can be estimated.

  According to the above procedure, the rotor displacement information Si0 (i = 1, 2,..., N) at the rotor geometric center at the predetermined rotation angle θz, and thus Si0 (θz) (i = 1, 2,..., In the above equation (15). , N) can be derived.

  Next, Gi0 (θz) (i = 1, 2,..., N) in the above formula (22) is the statics when the rotor is floated without rotating around the rotation axis and the bearing electromagnet at this time. It can be derived based on the measured supply current. In the block diagram shown in FIG. 13, the bearing control system is introduced in a state where the correction function based on the axial rotor rotation angle θz is introduced to the rotor displacement calculator 12 and the translational displacement command control system 20 is stopped. If all zero values are input as radial translation commands Xc and Yc, axial translational displacement commands Zc, radial rotational displacement commands θxc and θyc with respect to 10, the rotor does not rotate and floats statically. The steady deviation with respect to the command becomes zero by the action of the integrator in the PI controller 16, and the 5-degree-of-freedom rotor displacements X, Y, Z, θx, and θy that are the outputs of the rotor displacement calculator 12 are all held at zero values. .

  This 5-degree-of-freedom rotor displacement can be regarded as a true 5-degree-of-freedom rotor displacement because the rotor displacement calculator 12 introduces a correction function based on the axial-direction rotor rotation angle θz. 1 and 2, where M is gravity acceleration, g is gravitational acceleration, Fxt, Fyt, Fzt are true three-degree-of-freedom bearing forces acting on the rotor by magnetic bearings, and Nxt, Nyt are true radial two-degree-of-freedom bearing moments. In the fixed coordinate system shown in (1), the following static equations (23) and (24) hold.

  At this time, if the true magnetic attractive force generated by the bearing electromagnet is Fit (i = 1, 2,..., N), the true bearing forces Fxt, Fyt, Fzt, the true radial bearing moments Nxt, Nyt And the true magnetic attraction force Fit (i = 1, 2,..., N) is expressed by the above equation (18), where B is a 5 × n conversion matrix.

  In addition, the true magnetic attractive force Fit (i = 1, 2,..., N) in the bearing electromagnet is the measured supply current value for each bearing electromagnet Ii (i = 1, 2,..., N), The true gap length with the rotor suction surface is represented by the above equation (19) with Git (i = 1, 2,..., N) and the conversion coefficient k.

  Further, the true bearing electromagnet gap length Git (i = 1, 2,..., N) is defined as Gi0 (i = 1, 2,..., N) when the rotor is located at the geometric center. In the above equation (20), assuming that the true 5-degree-of-freedom rotor displacement is all zero, the following equation (25) is given.

  The above formulas (18), (19), and (25) are substituted into the above formulas (23) and (24), and the measured value of the bearing electromagnet supply current Ii (when statically levitated at a predetermined axial direction rotor rotation angle θz) By applying i = 1, 2,..., n), a nonlinear simultaneous equation relating to the bearing electromagnet gap length Gi0 (i = 1, 2,..., n) at the true rotor geometric center at the rotation angle θz is obtained. . This nonlinear simultaneous equation can derive a numerical solution by a calculation method such as Newton's method, and by performing the above procedure at a predetermined rotation angle θz, Gi0 (θz) (i = 1) in the above equation (22). 2, ..., n) can be derived. By configuring the gap length calculator 13 by the above equation (22), an error between the output of the gap length calculator 13 and the true bearing electromagnet gap length can be reduced. Therefore, the bearing in the bearing control system 10 can be reduced. The error between the force command and the radial direction bearing moment command and the true bearing force and the true radial direction moment acting on the rotor is reduced, and the disturbance generated in the magnetic bearing device can be further reduced.

  Thus, according to the fifth embodiment of the low disturbance control device of the present invention, the axial direction rotor rotational speed is in any frequency region within the position control band of the bearing control system 10, the servo resonance frequency region, and outside the position control band. Even in this case, the rotor center-of-gravity position G is positioned on the rotating shaft of the magnetic bearing, and the disturbance force due to the rotor unbalance can be reduced in all frequency regions including the servo resonance frequency region of the magnetic bearing. it can.

  Further, since the LPF 22 in the translational displacement command control system 20 extracts only the rotor rotation synchronization component, signal components belonging to a frequency region other than the rotor rotation synchronization component can be easily removed.

Furthermore, the bearing control system 10 is configured as a double loop control of a position control loop and a speed control loop, and the bearing control system 10 is designed so that the position control loop gain characteristic becomes flat, so that in the servo resonance frequency region of the magnetic bearing. In addition to being able to further suppress the amount of rotor swing and disturbance generated by the magnetic bearing device, the rotor is controlled so that the speed control band 51 does not belong to the vicinity of the axial rotor rotational speed f in the bearing control system 10. by varying the speed control loop gain K _D according to the rotational speed f, without impairing the stability of the bearing control system 10, achieve a further reduction of generation disturbance of the magnetic bearing apparatus in the speed control system gain crossover frequency range be able to.

  In addition, the bearing force command in the bearing control system 10 is reduced by reducing the error between the output of the rotor displacement calculator 12 and the true rotor displacement and the error between the output of the gap length calculator 13 and the true bearing electromagnet gap length. In addition, the error between the radial bearing moment command and the true bearing force and true radial bearing moment acting on the rotor is reduced, and the occurrence of disturbance in the magnetic bearing device can be further reduced.

Embodiment 6 FIG.
FIG. 15 is a block diagram for explaining the sixth embodiment of the low disturbance control device according to the present invention, where the same reference numerals as those in FIG. 7 denote the same or corresponding parts.

  Next, the operation will be described. In FIG. 15, for the sake of simplicity, the feedback loop of radial translation and axial translation is not shown, but the operation of the bearing control system 10 is the same as that of the fifth embodiment. The operation of the rotational displacement command control system 40 is the same as that of the third embodiment.

  In the low disturbance control device according to the fourth embodiment, a correction function based on the axial direction rotor rotation angle θz is introduced into the equation (15) in the rotor displacement calculator 12, and Si0 in the equation (15) is calculated. (Θz) (i = 1, 2,..., N) is derived based on the statics when the rotor is statically levitated without rotating around the rotation axis and the measured value of the supply current of the bearing electromagnet at this time. .

  On the other hand, in the low disturbance control device according to the fifth embodiment, the correction function based on the axial rotor rotation angle θz is expressed by the above equation (15) in the rotor displacement calculator 12 and the above equation (22) in the gap length calculator 13. ), And Si0 (θz) (i = 1, 2,..., N) in the above formula (15) is obtained when the rotor is mechanically constrained by a touchdown bearing for the purpose of protecting the magnetic bearing. Based on the rotor displacement information, Gi0 (θz) (i = 1, 2,..., N) in the above equation (22) represents the statics when the rotor is floated without rotating about the rotation axis, and at this time This is derived based on the measured value of the current supplied to the bearing magnet.

  As described above, the correction function derivation method in the rotor displacement calculator 12 includes a method based on rotor displacement information when the rotor is mechanically constrained by a touchdown bearing, statics when the rotor is statically levitated, and There are two methods based on the measured value of the supply current of the bearing electromagnet at this time. Of these, the latter is considered to be the method that can further reduce the error between the output of the rotor displacement calculator 12 and the true rotor displacement.

  Therefore, in the low disturbance control device of the sixth embodiment, the correction function based on the axial direction rotor rotation angle θz is expressed by the above equation (15) in the rotor displacement calculator 12 and the above equation (22) in the gap length calculator 13. ) And both Si0 (θz) (i = 1, 2,..., N) in the above formula (15) and Gi0 (θz) (i = 1, 2,..., N) in the above formula (22). Is derived based on the statics when the rotor is floated without rotating around the rotation axis and the measured value of the supply current of the bearing electromagnet at this time.

  As a derivation procedure at this time, first, as in the fifth embodiment, a correction function in the rotor displacement calculator 12 is derived based on the rotor displacement information when the rotor is mechanically restrained by the touchdown bearing. .

  Second, as in the fifth embodiment, the correction function in the gap length calculator 13 is derived based on the statics when the rotor is statically levitated and the measured current supplied to the bearing electromagnet at this time. . Further, in the low disturbance control device according to the sixth embodiment, the true bearing force and the above formulas (16) and (17), which are the statics when the rotor is statically levitated as in the fourth embodiment, The above equation (18), which is a relational expression between the radial bearing moment and the true electromagnet magnetic attraction force, the true electromagnet magnetic attraction force, the measured current supplied to each electromagnet, and the true gap between each electromagnet and the rotor attraction surface The above formula (19), which is a relational expression with respect to the length, and a correction function based on the axial direction rotor rotation angle θz are introduced, and the above formula (22) for calculating the true bearing electromagnet gap length is substituted, and a predetermined axial direction By applying the bearing electromagnet supply current measurement value Ii (i = 1, 2,..., N) in the case of static levitation at the rotor rotation angle θz, the true 5-DOF rotor displacement Xt, Yt at the rotation angle θz is applied. , Z , You get θx, the non-linear simultaneous equations related to θy.

  By calculating a numerical solution of this nonlinear simultaneous equation, the output error of the rotor displacement calculator 12 at a predetermined rotation angle θz, and thus Si0 (θz) (i = 1, 2,..., N) in the above equation (15). Can be derived with higher accuracy.

  As a result, the error between the output of the rotor displacement calculator 12 and the true rotor displacement can be further reduced. Therefore, the bearing force command and the radial bearing moment command in the bearing control system 10 and the true force acting on the rotor can be reduced. The error between the bearing force and the true radial bearing moment is reduced, and the magnetic disturbance generated in the magnetic bearing device can be further reduced.

  Thus, with the low disturbance control device according to Embodiment 6 of the present invention, the axial direction rotor rotational speed is in any frequency region within the position control band of the bearing control system 10, the servo resonance frequency region, and outside the position control band. Even in this case, the rotor inertia main shaft P is parallel to the magnetic bearing rotating shaft, and the disturbance moment caused by the rotor dynamic imbalance can be reduced in the entire frequency region including the servo resonance frequency region of the magnetic bearing.

  Further, since the LPF 42 in the rotational displacement command control system 40 extracts only the rotor rotation synchronization component, signal components belonging to a frequency region other than the rotor rotation synchronization component can be easily removed.

Furthermore, the bearing control system 10 is configured as a double loop control of a position control loop and a speed control loop, and the bearing control system 10 is designed so that the position control loop gain characteristic becomes flat, so that in the servo resonance frequency region of the magnetic bearing. In addition to being able to further suppress the rotor swing amount and the disturbance generated in the magnetic bearing device, in the bearing control system 10, the speed control band 51 does not belong to the vicinity of the axial rotor rotational speed f. by varying the speed control loop gain K _D according to the rotor rotational speed f, without impairing the stability of the bearing control system 10, a further reduction of generation disturbance of the magnetic bearing apparatus in the speed control system gain crossover frequency range Can be planned.

  In addition, the bearing force command in the bearing control system 10 is reduced by reducing the error between the output of the rotor displacement calculator 12 and the true rotor displacement and the error between the output of the gap length calculator 13 and the true bearing electromagnet gap length. In addition, the error between the radial bearing moment command and the true bearing force and true radial bearing moment acting on the rotor is reduced, and the occurrence of disturbance in the magnetic bearing device can be further reduced.

  The present invention is used to reduce disturbance generated by a magnetic bearing that supports a rotating body (rotor) of a rotating electrical machine in a non-contact manner in all frequency ranges including a servo resonance frequency range of the magnetic bearing.

It is a block diagram for demonstrating the example of arrangement | positioning of the rotor which is a component of a magnetic bearing apparatus, an electromagnet, and a displacement detection means. They are a front view (a) and AA sectional view (b) of a magnetic bearing device in which six electromagnets 2a to 2f and six displacement detection means 3a to 3f are arranged around the inclined magnetic pole ring rotor 1. It is a block diagram for demonstrating Embodiment 1 of the low disturbance control apparatus which concerns on this invention. FIG. 4 is a rotor radial direction cross-sectional view for explaining the low disturbance control device of the first embodiment. It is a block diagram for demonstrating Embodiment 2 of the low disturbance control apparatus which concerns on this invention. FIG. 5 is a rotor radial direction cross-sectional view for explaining a low disturbance control device of a second embodiment. It is a block diagram for demonstrating Embodiment 3 of the low disturbance control apparatus which concerns on this invention. FIG. 10 is a Bode diagram showing closed loop gain characteristics for explaining the low disturbance control device according to the third embodiment. FIG. 6 is a rotor cross-sectional view for explaining a third embodiment. FIG. 6 is a rotor cross-sectional view for explaining a third embodiment. FIG. 6 is a rotor cross-sectional view for explaining a third embodiment. It is a block diagram for demonstrating Embodiment 4 of the low disturbance control apparatus which concerns on this invention. It is a block diagram for demonstrating Embodiment 5 of the low disturbance control apparatus which concerns on this invention. FIG. 10 is a diagram showing an arrangement of displacement detection means and rotor displacement detection surfaces in data measurement for deriving a correction function according to the fifth embodiment. It is a block diagram for demonstrating Embodiment 6 of the low disturbance control apparatus which concerns on this invention.

Explanation of symbols

1 rotor, 2 electromagnets, 3 displacement detection means, 10 bearing control system,
11 components comprising an electromagnet, a rotor and displacement detection means, 12 a rotor displacement calculator,
13 Gap length calculator, 14 Power distributor, 15 PID controller, 16 PI controller, 17 P controller, 18 Differentiator, 20 Translational displacement command control system,
21, 41 Rotary coordinate converter, 22, 42 LPF, 23, 43 integrator,
24 fixed coordinate converter, 25, 45 fixed coordinate converter / phase converter,
30 Swinging force due to rotor unbalance,
31 Rotary coordinate system representation of radial direction bearing force command,
32 Rotary coordinate system representation of radial direction translational displacement command, 33, 63 Rotor rotation direction,
34 Rotor geometric center position moving direction vector, 40 rotational displacement command control system,
50 Position control closed loop gain characteristics, 51 Speed control closed loop gain characteristics,
60 Swinging moment due to rotor dynamic imbalance,
61 Rotating coordinate system representation of radial direction bearing moment command,
62 Rotational coordinate system representation of radial direction rotational displacement command,
64 rotational direction vector of the rotor inertial spindle, 70 displacement detecting means,
71 Rotor displacement detection direction, 72 Rotor displacement detection surface, 73 Rotor rotation axis (Z axis).

Claims (12)

In a fixed coordinate system in which a radial direction is an X axis and a Y axis and a central axis is a Z axis of a magnetic bearing composed of a plurality of electromagnets that levitate a rotor by electromagnetic force, the geometric central axis of the rotor translates in the radial direction. 3 degree-of-freedom rotor displacement in which the translational displacement in the radial direction and the geometrical center axis of the rotor translate in the axial direction (Z-axis direction) of the fixed coordinate system, and the geometrical center axis of the rotor are fixed. Displacement detection for detecting information (rotor displacement information) related to 5-degree-of-freedom rotor displacement and axial-direction rotor-rotation angle consisting of 2-degree-of-freedom rotor displacement of radial-direction rotational displacement rotating in a plane including the Z-axis of the coordinate system Means,
A rotor displacement calculator for converting the output of the displacement detection means into the 5-degree-of-freedom rotor displacement; and a bearing force for controlling the rotor to a predetermined position of the magnetic bearing based on the output of the rotor displacement calculator. A control command output means for outputting a radial direction and axial direction bearing force command, and a radial direction bearing moment command serving as a bearing force for controlling the radial rotational displacement of the rotor;
Based on the output of the rotor displacement calculator, a gap length calculator that outputs the gap length between each of the electromagnets and the rotor ;
The electromagnet for realizing the radial direction and axial direction bearing force command and the radial direction bearing moment command output from the control command output means based on the output of the gap length calculator and the output of the control command output means. A bearing control system including a power distributor that distributes and supplies a supply current to each ;
Based on the rotor rotation angle in the axial direction of the rotor, the radial bearing force command output by the control command output means in the bearing control system is expressed as follows: the geometric center axis of the rotor is the Z axis, and the direction perpendicular to the Z axis is X A rotary coordinate converter for converting into a rotary coordinate system representation that rotates about the Z axis with the rotor as an axis and a Y axis;
LPF for extracting the rotor rotation synchronization component of the output of the rotary coordinate converter;
An integrator that integrates the output of the LPF and outputs a radial translational displacement of a rotating coordinate system that translates in the radial direction;
Based on the axial rotor rotation angle of the rotor, the radial translation displacement output from the integrator is converted into the fixed coordinate system representation so that the center of gravity of the rotor is located at the origin of the rotary coordinate system. translational displacement command control system that includes a fixed coordinate converter for calculating a radial translational displacement command for translating the geometric center axis of the radial direction,
With
A magnetic bearing low disturbance control device, wherein the bearing control system controls the electromagnet to control the flying position of the rotor to a predetermined position by a radial translational displacement command converted into the fixed coordinate system. In a fixed coordinate system in which a radial direction is an X axis and a Y axis and a central axis is a Z axis of a magnetic bearing composed of a plurality of electromagnets that levitate a rotor by electromagnetic force, the geometric central axis of the rotor translates in the radial direction. 3 degree-of-freedom rotor displacement in which the translational displacement in the radial direction and the geometrical center axis of the rotor translate in the axial direction (Z-axis direction) of the fixed coordinate system, and the geometrical center axis of the rotor are fixed. Displacement detection that detects information (rotor displacement information) related to the 5-degree-of-freedom rotor displacement and the axial-direction rotor-rotation angle consisting of a 2-degree-of-freedom rotor displacement of a radial-direction rotational displacement that rotates in a plane including the Z-axis of the coordinate system Means,
A rotor displacement calculator for converting the output of the displacement detection means into the 5-degree-of-freedom rotor displacement;
Based on the output of the rotor displacement calculator, a radial and axial direction bearing force command that becomes a bearing force for controlling the rotor to a predetermined position of the magnetic bearing, and a bearing force for controlling the radial rotational displacement of the rotor Control command output means for outputting a radial bearing moment command,
Based on the output of the rotor displacement calculator, a gap length calculator that outputs the gap length between each of the electromagnets and the rotor ;
The electromagnet for realizing the radial direction and axial direction bearing force command and the radial direction bearing moment command output from the control command output means based on the output of the gap length calculator and the output of the control command output means. A bearing control system including a power distributor that distributes and supplies a supply current to each ;
Based on the rotor rotational angle in the axial direction of the rotor, the radial bearing moment command output by the control command output means in the bearing control system is expressed as follows: the geometric center axis of the rotor is the Z axis, and the direction perpendicular to the Z axis is X A rotary coordinate converter that converts the rotary coordinate system to rotate around the Z axis together with the rotor as an axis and a Y axis;
LPF for extracting the rotor rotation synchronization component of the output of the rotary coordinate converter;
An integrator for outputting a radial rotational displacement of the rotating coordinate system that rotates in the radial direction by integrating the output of the LPF,
Based on the rotor rotational angle in the axial direction of the rotor, the radial rotational displacement output from the integrator is converted into the fixed coordinate system representation so that the inertial main shaft of the rotor is parallel to the central axis of the magnetic bearing. A rotational displacement command control system comprising: a fixed coordinate converter that calculates a radial rotational displacement command for rotating the geometric center axis of the rotor in a plane including the Z axis of the fixed coordinate system;
With
A magnetic bearing low disturbance control device, wherein the bearing control system controls the electromagnet to control the flying position of the rotor to a predetermined position by a radial rotational displacement command converted into the fixed coordinate system. 3. A low disturbance control device for a magnetic bearing according to claim 1, wherein the LPF has a narrow frequency band of about 1 Hz. When the fixed coordinate converter of the translational displacement command control system converts the output of the integrator into a fixed coordinate system expression, the phase characteristic of the bearing control system is taken into account and the predetermined value is determined according to the axial direction rotor rotational speed. The magnetic bearing low disturbance control device according to claim 1, wherein a signal obtained by advancing the phase amount is converted into a fixed coordinate system representation and output. When the fixed coordinate converter of the rotational displacement command control system converts the output of the integrator into a fixed coordinate system expression, the phase characteristic of the bearing control system is taken into consideration and the predetermined value is determined according to the axial direction rotor rotational speed. 3. A low disturbance control device for a magnetic bearing according to claim 2, wherein a signal obtained by advancing the phase amount is converted into a fixed coordinate system representation. The control command output means of the bearing control system includes a position control loop for outputting a speed command of 5 degrees of freedom based on a deviation between the 5 degrees of freedom displacement command and the 5 degrees of freedom rotor displacement and a differential value of the 5 degrees of freedom rotor displacement 2. A double loop control of a speed control loop that performs speed control based on a deviation between the speed command of 5 degrees of freedom and a position control closed loop gain characteristic is controlled to be flat. 2. A low disturbance control device for a magnetic bearing according to 2. 7. The magnetic bearing according to claim 6, wherein a speed control loop gain is changed in accordance with the axial rotor rotational speed so that the speed control band does not belong to the vicinity of the axial rotor rotational speed. Low disturbance control device. 3. The magnetic bearing low disturbance control device according to claim 1, wherein the rotor displacement calculator has a correction function for reducing an error of the rotor displacement with an output of 5 degrees of freedom with respect to the true rotor displacement. A touchdown bearing for protecting the magnetic bearing is provided, and the correction function is derived based on rotor displacement information when the rotor is mechanically constrained by the touchdown bearing. 8. A low disturbance control device for a magnetic bearing according to claim 8. The magnetic bearing low disturbance control device according to claim 8, wherein the correction function is derived based on statics when the rotor is statically levitated and a measured value of the supply current of the bearing electromagnet. 3. The magnetic bearing low disturbance control device according to claim 1, wherein the gap length calculator has a correction function for reducing an error of an output gap length with respect to a true gap length. The magnetic bearing low disturbance control device according to claim 11, wherein the correction function is derived based on statics when the rotor is statically levitated and a measured value of the supply current of the bearing electromagnet.

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