JP2001258290A - Method for constructing independent control system for rotating machine having no magnetic flux detection bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a current to control the position in the radial direction of a bearingless motor by a controller independent of a motor driving inverter. SOLUTION: The magnetic flux of a gap is detected by detecting the terminal voltage and current of a motor winding, and performing a calculation using these detected signals. By obtaining the detected magnetic flux of the gap, a modulating circuit for the position in the radial direction of the bearingless motor is operated. As a result, operation is performed by the controller independent of that of the motor, and current is caused to flow in a control winding for position in the radial direction and the position in the radial direction of its main shaft is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a bearingless rotating machine that generates torque and radial force by one electromagnetic machine. For bearingless rotating machines,
There are already a large number of documents. For example, a commentary from the Institute of Electrical Engineers Tadashi Fukao, Akira Chiba "Bearingless motor"
ol. 117 no. 9 pp. 612-615 1997
August is easy to understand for beginners. further,
For generalized theory, see Akira Chiba, T
azumi Deido, Tadashi Fuka
o and M.S. A. Rahman, "An Anal
ysis ofBearingless ac Mot
ors ", IEEE Transaction on
Energy Conversion, vol. 9, n
o. 1 March, 1994, pp. 61-68 proposes a basic theory applicable to many motors and generators. Furthermore, basic analysis methods include Akira Chiba, Koichi Ikeda, Fukuzo Nakamura, Tazumi Muddo, Tadashi Fukao, M. A. Rahman, "Principle of Radial Force Generation in No Load of Bearingless Motor with Cylindrical Rotor," IEEJ Transactions on Electronics, Vol. 113, no. 4, pp. 539
−547, 1993 are easy to understand. For permanent magnet machines, see Masahide Oshima, Satoru Miyazawa, Tadashi Muddo, Akira Chiba, Fukuzo Nakamura, Tadashi Fukao, "Analysis and Basic Characteristics of Permanent Magnet Type Bearingless Motor," Transactions of the Institute of Electrical Engineers of Japan, vol. 115-D, no.
9, pp. 1131-1139, 1995, and in synchronous reluctance machines, Osamu Ichikawa, Riki Michioka, Akira Chiba, Tadashi Fukao "Analysis of radial force of bearingless reluctance motor and configuration of shaft position control device" IEEJ Transactions on Engineering, vol. . 117-D pp. 1123-1131199
July (the IEEJ Best Paper Award) will be helpful.

[0002]

2. Description of the Related Art Applicants have already calculated the magnitude and phase delay of a loaded current based on vector control theory as a stabilization control method for a loaded bearingless induction machine, and feed-forwarded the primary current. We propose a decoupling method for radial force that compensates for phase and amplitude and adjusts the magnitude and position of magnetic flux. In this control method, the command of the magnetic flux generated by the controller of the motor drive inverter is obtained, and the current generated by the radial force controller is determined. become. That is, in the conventional bearingless rotating machine system, the rotation angle position of the rotating magnetic field is obtained from the motor-driven control controller. For this reason, the motor control controller and the controller that supports the main shaft with electromagnetic force are often composed of the same hardware. Even in the case of another configuration, the rotating magnetic field position signal is obtained from the motor control controller. If the motor control and the radial position control are separated and independent, a general-purpose inverter, a commercial power supply, or the like can be used for driving the motor, and the development period and cost can be easily reduced. In order to control the radial position independently, it is necessary to obtain the magnetic flux position.

A system of a bearingless motor using magnetic flux feedback has already been proposed in the following paper. Akira Chiba, Tadashi Fukao "Analysis of DC Machine Model of Bearingless Motor and Application to AC Machine" Proceedings of the 8th JSME "Electromagnetics-Related Dynamics" Symposium, pp. 499-504, May 1996, Northern Topia Schob, J .; Bichsel: "VECTOR
CONTROL OF THE BEARINGLR
SS MOTOR ", 4th International
al Symposium on Magnetic
Bearings, Zurich 1994, p. Three
27-332 However, these systems do not find the concept of an independent control configuration. Thus, the inventors have already proposed a magnetic flux feedback control method using a search coil as an independent control configuration, and have proposed in the following paper the decoupling of the radial force and the application to a square wave inverter. Ito, Tsukagoshi, Chiba, Fukao: "Proposal of magnetic flux detection type bearingless drive system", 1152 National Conference of the Institute of Electrical Engineers of Japan 1152 Influence on Search Coil Magnetic Flux Detection ", 1999 IEICE National Application Conference 15: However, the work of applying a search coil to the stator teeth is complicated, and the control becomes unstable during cutting. In addition, it is necessary to consider the influence of the spatial harmonic and the radial force magnetic flux on the search coil magnetic flux. Further, there is no concept of storing the shaft supporting function in a separate case or in a rotating machine.

[0004]

In the bearingless rotating machine system, the motor control and the spindle support control system exchange signals, and are not independent. Therefore, it is difficult to use a general-purpose inverter, a commercial drive power supply, a power supply for driving a large number of units, or the like, which is difficult to exchange signals, as a motor drive power supply. Therefore, a power source such as a dedicated inverter is required, and there is a problem that the cost is increased. Further, the power supply has a large physical shape, and as a result of extending the wiring from the search coil, a failure is likely to occur, and there is a problem that the support of the spindle is difficult.

It is an object of the present invention to realize a bearingless rotary machine system in which a motor drive power supply system operates independently, while a spindle supporting power supply system operates independently of the motor drive power supply system. Since the motor drive power supply system can be operated independently, it is possible to supply a general-purpose power supply such as a general-purpose inverter or a commercial power supply. However, the spindle support mechanism needs to have a detection function for detecting the position, magnitude, and the like of the rotating magnetic field. This detection is obtained by calculation from the terminal voltage and current of the motor.

[0006]

As shown in FIG. 1, a stator includes a winding 6 for generating torque and a winding 7 for generating a radial force, and the winding for generating torque supplies power. The motor drive power supply 2 is connected to the motor drive power supply 2 and has a function of operating independently of the spindle support controller. On the other hand, a winding for generating a radial force is a control power supply for supplying a desired voltage and current to the windings. 5, the control power supply has a function of supplying a voltage and a current generated by the controller 3, and has a function of detecting a radial displacement of the main shaft. The controller is based on the radial displacement sensors 8 and 9 of the main shaft. A function for determining a current for stably supporting the main shaft with an electromagnetic force, and a function 4 for detecting a position of a rotating magnetic field for determining the current. End of Voltage, performed by the function of calculating on the basis of the current, it is not necessary to obtain the rotational angular position information signal from the motor drive power, the bearingless rotary machine 1, characterized in that it is configured to independently system.

In a bearingless rotating machine system, a controller has a function of determining a voltage instead of a current in a bearingless rotating machine system. Even when the windings are not independent, by taking the sum of the voltages, it is possible to assume that another winding is provided by using the principle of superposition.

In a bearingless rotating machine system, a bearingless rotating machine system having a function of estimating a position of a rotating magnetic field only from a current of a torque generating winding. It is possible to measure the motor constant in advance, or to measure the motor constant in real time. The terminal voltage can be calculated by calculation from the motor constant measurement result and the current value. As a result, it becomes unnecessary to detect the terminal voltage. Similarly, it is also possible to detect the voltage and omit the current detection.

A bearingless rotating machine system in which a motor drive power supply is a commercial power supply in the bearingless rotating machine system. With a bearingless rotating machine system,
A bearingless rotating machine system in which the motor drive power supply consists of a general-purpose inverter. A bearingless rotating machine system in which a motor drive power supply is composed of a power supply that drives a number of electric motors.
There is no restriction on the power source of the motor, and various power sources can be connected. It is also possible to use the electric motor in the regenerative mode as a generator. It is possible to realize a generator system in which many units are connected.

In the bearingless rotating machine system, the rotating machine is a disk-type rotating machine, and a direction in which an electromagnetic force is generated to support a main shaft is an axial direction. A bearing disk rotating machine has been proposed which controls not only a radial force but also an electromagnetic force in an axial direction and a tilt direction. The concept of the present invention can be applied to this disc-type bearingless motor, and tilt control, axial position control, and the like are configured by a separate power supply.

In a bearingless rotating machine system, a main shaft supporting function such as a control power supply, a controller, a function of detecting a radial displacement, and a function of detecting a position of a rotating magnetic field is housed in a case separate from a motor drive power supply. Bearingless rotating machine system. Since it can be configured independently of the motor drive power supply or the generator output terminal connection load, the main shaft support mechanism is physically separated. Therefore, the part supporting the spindle support function is housed in a case separate from the power supply of the electric motor.

Further, in the bearingless rotating machine system, a spindle support function is incorporated in the bearingless rotating machine. This system not only houses the spindle support function in a separate case, but also mechanically fixes the case to a bearingless rotating machine. Alternatively, the case itself is configured to be housed in the frame of the bearingless rotating machine. Then, if it is a three-phase machine,
In the case of three wires and a single-phase machine, only two wires are connected to the outside from the bearingless rotating machine.

The bearingless rotating machine system has a function of integrating a terminal voltage, a function of detecting a current, a function of integrating a detected current, and a product of a current integrated value and a winding resistance. A bearingless rotating machine having a rotating magnetic field detection function of calculating a primary interlinkage magnetic flux by subtracting from a voltage integral value and calculating a gap magnetic flux by further reducing a magnetic flux of a leakage inductance.

After the primary interlinkage magnetic flux is calculated in the bearingless rotating machine system, a specific magnetic flux such as a secondary interlinkage magnetic flux, a gap magnetic flux, or a magnetic flux vector located between the magnetic fluxes is calculated as a magnetic flux vector. Among them, a bearingless rotating machine that uses a magnetic flux detector that detects a magnetic flux vector that does not cause interference on two orthogonal axes of a radial force. Conventionally, it has been assumed that the primary leakage inductance and the secondary leakage inductance are equal in an induction machine. Even if this assumption was set, the relationship between the voltage, current, and shaft torque expected from the terminal hardly changed. However, in a bearingless rotating machine, the differential value of the air gap magnetic flux with respect to the radial position is related to the generation of the radial force. Therefore, assuming that the values of the primary leakage and the secondary leakage are equal, the direction of the generated radial force is shifted. There is a risk that it will. Therefore, it is necessary to carefully select a magnetic flux to be oriented so that the radial force command value generated in a feedforward manner and the actual radial force match. This magnetic flux does not always coincide with the conventional gap magnetic flux in which the primary leakage is assumed to be equal to the secondary leakage, and the magnetic flux is inclined in the primary magnetic flux direction from the gap magnetic flux, or conversely.
It is inclined in the next magnetic flux direction.

Similarly, a reluctance machine, a permanent magnet synchronous machine,
In a general field winding type synchronous machine or the like, a gap magnetic flux is obtained by vectorwise subtracting a leakage inductance from a primary interlinkage magnetic flux.

In a bearingless rotating machine system, a bearingless rotating machine system in which the position of a rotating magnetic field is detected in a stator, for example, using a search coil or a Hall element.

As is well known, the radial displacement sensor can be replaced with a function for estimating displacement from self-inductance or mutual inductance. In addition, the windings that generate torque and the windings that generate radial force do not need to be physically separate, and can be the same winding. It is possible. Further, a power supply is not necessarily required for the winding for supporting the main shaft, and the winding itself may be operated to obtain regenerative power to obtain energy. The type of the rotating machine may be any type such as an induction machine, a permanent magnet machine, a synchronous machine, and a reluctance machine. Further, it may operate as a generator or an electric motor.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention proposes a method for estimating a gap magnetic flux from a primary voltage and a current, and confirms decoupling of a radial force and stable magnetic force support when a square wave inverter is applied.

The estimation of the gap magnetic flux is obtained by converting the primary voltage and current into a stationary coordinate system by three-phase to two-phase conversion and obtaining an equivalent circuit of the induction machine on the α and β axes. First, the primary linkage flux vector λ _αβ
Is

(Equation 1) And the secondary flux linkage vector λ _αβ

(Equation 2) It is. Therefore, the gap magnetic flux vector λ _αβg is

(Equation 3) become. _However, v αβg; primary voltage vector _i αβs; primary current vector r _s; primary resistance L _s; primary self-inductance L _r; secondary side self inductance L _m; exciting inductance L _1s; primary leakage inductance L _1r; two Secondary side leakage inductance σ; leakage coefficient FIG. 2 is a block diagram showing the above calculation process.

In a synchronous machine, a permanent magnet machine, etc., the flux linkage of the stator winding is obtained by the equation (1), and the gap magnetic flux can be obtained by reducing the magnetic flux due to the leakage inductance in a vector manner.

The modulation formula of the bearingless motor is as follows.

(Equation 4) Here, M ′ ₍₂₎ is a constant, and _Im is an exciting current.
M _'(2) I _m is the unit of Wb / m, a differential value in the radial force generating windings with respect to the radial direction position of the magnetic flux linked. In the system for estimating the gap magnetic flux, | λ _αβg |
There is assumed to be proportional to M _{'(2) I m.}

FIG. 3 shows a system configuration for estimating the gap magnetic flux. Calculated from the block diagram of FIG. For this purpose, the following calculation is performed.

(Equation 5)

(Equation 6) By substituting equations (5) and (6) into equation (4),
The position control system can accurately grasp the phase and amplitude of the rotating magnetic field,
Radial forces F _α , F corresponding to F _α *, F _β *, respectively
_β occurs.

[0023]

The proposed system confirms whether the radial force can be made non-interfering even under load. FIG.
Represents the relationship between the command values _Fα * and _Fβ * of the radial force with respect to the slip when the radial force is generated in the β negative direction. The vertical axis uses the PU method, and F _β at no load
* Based on the standard. Originally, when a radial force is generated in the β negative direction, the control system should generate only _Fβ *. However, if the position controller cannot accurately grasp the position and amplitude of the rotating magnetic field, _Fα * also occurs. And cause mutual interference. In a conventional no-load of the system, as slip increases, it was mutual interference becomes large F _alpha *. Even in the system proposed this time, _Fα * does not occur even under load, and it can be seen that decoupling can be realized.

A major difference between the system proposed in the present invention and the conventional system is that the motor control and the position control are completely independent in the control system. Therefore, it is considered that the power supply of the motor unit is not limited to the vector control inverter, and the options are expanded. FIG. 5 shows the power source of the motor unit.
12000r / mi when using a square wave inverter
n, unloaded 4-pole during the u-phase current i _{u4, u} Aioko force direction component in the gap magnetic flux estimation lambda _.alpha.g, shows a magnetic flux [psi _cos, beta direction of displacement waveforms by the search coil. From this figure, [psi _cos, lambda phase matching of _.alpha.g is confirmed, also be confirmed phase matching of i _u4 and lambda _.alpha.g since still more unloaded. In addition, the gap between the touchdown bearing and the rotor of the prototype is 100 μm, and the whirling of the displacement waveform β is 3 μm, which indicates that stable magnetic force is supported.

As described above, according to the present invention, it has been confirmed that a system for estimating the gap magnetic flux is constructed and the rotating magnetic field is estimated. This system is an effective method for simplifying the system of the power supply unit because it can be made non-interfering without applying a search coil and the options of the power supply of the motor unit are widened.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is a block diagram for detecting a gap magnetic flux from a terminal voltage and a current.

FIG. 3 is a configuration example of a bearingless motor using an estimated value of a gap magnetic flux.

FIG. 4 is an experimental result of the system shown in FIG. 3, which shows that the radial force is decoupling compared to the previous method.

FIG. 5 is an example showing that radial force control can be performed independently, and shows a motor current when driven by a square wave inverter, a detected magnetic flux of a search coil, a magnetic flux detected waveform by a proposed method, and an axis. The figure of the example which showed shake.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bearingless rotating machine 2 motor control power supply 3 controller 4 rotating magnetic field detector 5 control power supply 6 torque generating winding 7 radial force generating winding 8 displacement sensor 9 displacement sensor

[Procedure amendment]

[Submission date] July 7, 2000 (200.7.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J102 AA01 BA03 BA17 CA16 CA19 DA03 DA09 DB05 DB10 DB37 GA13 5H571 BB07 CC05 GG01 GG04 GG05 HD01 JJ04 JJ22 LL22 LL23 LL27 5H576 DD02 DD04 DD05 DD07 DD09 EE01 0404 GG01GG 01GG 04GG JJ22 LL22 LL24 LL34 LL35 LL39 5H607 AA12 BB01 BB05 BB21 BB25 DD06 DD15 GG21

Claims (1)

1. A stator comprising a winding set for generating torque and a winding set for generating a radial force on a stator, wherein the winding for generating torque is connected to a motor drive power supply for supplying electric power. This motor drive power supply has the function of operating independently of the spindle support controller, while the winding that generates a radial force has a desired voltage on the winding,
Connected to a control power supply that supplies current, the control power supply has a function of supplying voltage and current generated by the controller, and based on the function of detecting the radial displacement of the main shaft, the controller is based on the radial displacement of the main shaft. It has a function to stably determine the current for supporting the main shaft by electromagnetic force, and has a function to detect the position of the rotating magnetic field to determine the current. A bearingless rotating machine system, which is performed by a function of calculating based on voltage and current, and does not need to obtain a rotation angle position information signal from a motor drive power supply, and is configured independently. 2. The bearingless rotating machine system according to claim 1, wherein the controller has a function of determining a voltage instead of a current. 3. The bearingless rotating machine system according to claim 1, further comprising a function of estimating the position of the rotating magnetic field only from the current of the torque generating winding. 4. A bearingless rotating machine system according to claim 1, wherein the motor driving power source is a commercial power source or a multi-unit driving power source. 5. A bearingless rotating machine system according to claim 1, wherein the motor drive power supply is constituted by a general-purpose inverter. 6. A bearingless rotating machine system according to claim 1, wherein the rotating machine is a disk-type rotating machine, and a direction in which an electromagnetic force is generated to support the main shaft is an axial direction. 11. A bearingless rotating device according to claim 1, wherein the main shaft supporting mechanism, such as a control power supply, a controller, a function of detecting a radial displacement, and a function of detecting a rotating magnetic field position, is housed in a case separate from the motor drive power supply. Machine system. 8. The bearingless rotating machine system according to claim 1, wherein the spindle support function is built in the bearingless rotating machine. 9. The method according to claim 1, further comprising a function of integrating a terminal voltage, a function of detecting a current, a function of integrating a detected current, and a product of a current integrated value and a winding resistance. Calculate the primary flux linkage by subtracting from the terminal voltage integral,
In addition, a bearingless rotating machine with a rotating magnetic field detection function that calculates the gap magnetic flux by reducing the magnetic flux of the leakage inductance. 11. A magnetic flux vector according to claim 9, wherein after calculating the primary interlinkage magnetic flux, a specific interlinkage magnetic flux such as a secondary interlinkage magnetic flux, a gap magnetic flux, or a magnetic flux vector located between these magnetic fluxes is used as a magnetic flux vector. A bearingless rotating machine that uses a magnetic flux detector that detects a magnetic flux vector that does not cause interference on two orthogonal axes of radial force. 12. A bearingless rotating machine system for detecting a rotating magnetic field position in a stator using a detector, for example, a search coil or a Hall element according to claim 7-8.