JPH1070865A - Bearingless rotary equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to reduce a required number of power switching elements of power amplifiers, by connecting the output terminals of a plurality of power amplifiers to one of terminals of corresponding windings, and other terminals of the windings to common connections. SOLUTION: Slots corresponding to 12 magnetic poles are provided on inner peripheral surface of a stator 10, and 12 independent single-pole windings #1 to #12 are provided. And one side terminals of these 12 single-pole windings #1 to #12 are respectively connected to a common neutral point 16. On the other hand, other terminals of the single-pole windings #1 to #12 are connected to the output terminals of the power amplifiers B1 to B12 of a controller. That is, one power line from each of single-pole windings #1 to #12 is connected to the output terminals of the power amplifiers B1 to B12. By doing this, the required number of power switching elements of the power amplifiers B1 to B12 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating magnetic field obtained by superposing a rotating magnetic field of M poles and a rotating magnetic field of M. +-. 2 poles on a rotor to control the floating of the rotor to a target position and to control the floating of the rotor. More particularly, the present invention relates to a connection structure of a power amplifier for supplying an exciting current to a stator winding of a bearingless rotating machine.

[0002]

2. Description of the Related Art Japanese Patent Laid-Open Publication No. Hei 6-133493 discloses an example of a bearingless rotating machine (magnetic levitation induction motor). This is achieved by generating a rotating magnetic field in which a rotating magnetic field of M poles and a rotating magnetic field of M ± 2 poles are superimposed on the stator.
Rotational force and levitation force are applied to the rotor by the mutual magnetic action between the rotating magnetic field and the conductor.

FIG. 4 shows an example of such a bearingless rotating machine. Slots corresponding to twelve magnetic poles are provided on the inner peripheral surface of the stator 10, and twelve independent single-pole windings # 1 to #
12 is stored. Displacement sensors 14A and 14B are attached to the outer peripheral surface of the shaft 13 in a direction perpendicular to the shaft 13. The displacement sensors 14A and 14B detect displacements of the shaft 13 in the X and Y directions, respectively, and input the displacements to the control unit 21 of the controller 20. Displacement sensor 14
The signals of A and 14B are amplified and operated in the control unit 21 to generate a rotating magnetic field of M pole for rotating the rotor 15 on the inner peripheral surface of the stator 10 and a signal for causing the rotor 15 to float. A current for generating a rotating magnetic field of ± 2 poles on the inner peripheral surface of the stator 10 is calculated for each of the windings # 1 to # 12,
Output each of those values.

[0004] Each of the arithmetically processed current signals is amplified by power amplifiers A1 to A12 and supplied to the winding of each magnetic pole as an exciting current. Thereby, sufficient rotational force and floating force are obtained for the rotor 15. The floating principle of a bearingless rotating machine is described, for example, in Japanese Patent Application Laid-Open No. Hei.
No. 7, for example.

The windings # 1 to # 12 forming the stator magnetic poles are arranged in slots provided on the inner peripheral surface of the stator 10 and form a unipolar magnetic field. Both terminals of the winding are connected to a pair of balanced output terminals of the corresponding power amplifiers A1 to A12, respectively. In this example, since the windings # 1 to # 12 of the stator have twelve phases, the power amplifiers for supplying the exciting current are twelve single-phase power amplifiers (A1 to A1).
2) Required.

FIG. 5 shows the connection between the output circuit of the power amplifier and the windings of each stator. The output stage of each power amplifier is
As shown in the figure, it is configured as a full bridge type balanced output circuit of four power switching elements. For example, T
R1 is ON, TR2 is OFF, TR3 is OFF,
When TR4 is ON, a current flows in the direction indicated by the arrow in the figure. Conversely, TR1 is OFF and TR2 is ON
When TR3 is ON and TR4 is OFF, a current flows in a direction opposite to the arrow shown in the figure.

[0007]

However, in the above-mentioned configuration, the number of power switching elements required at the output stage of the power amplifier is increased, and the number of connection wirings of the power amplifier is increased. As a result, the cost of the apparatus is increased. This leads to an increase in size.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bearingless rotating machine device in which the required number of power switching elements of a power amplifier is reduced and the overall size of the device is reduced. It is the purpose.

[0009]

SUMMARY OF THE INVENTION A bearingless rotating machine device according to the present invention includes a plurality of windings for applying a rotating magnetic field in which a rotating magnetic field of M poles and a rotating magnetic field of M ± 2 poles are superimposed on a rotor. A stator magnetic pole, a power amplifier that supplies current to the windings of the stator magnetic pole, and a control circuit that drives the power amplifier. An output terminal of each of the plurality of power amplifiers is connected to one terminal of a corresponding winding, and the other terminal of each winding is commonly connected.

Further, the sum of the currents flowing from the output terminals of the plurality of power amplifiers to the corresponding windings is zero.

Further, the output terminal of the power amplifier is obtained from a middle point of two power switching elements connected in series to a DC power supply.

Since one terminal of the winding of the stator pole is connected in common and the other terminal is connected to the output terminal of the corresponding power amplifier, two power switching elements are provided at the output stage of the power amplifier. If necessary, the required exciting current can be supplied to the stator winding. For this reason, the number of power switching elements and the number of wirings of the power amplifier are reduced by half, and the manufacturing cost and size of the device can be reduced.

[0013]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a structure of a connection portion of a drive control device for a bearingless rotating machine according to an embodiment of the present invention. Slots corresponding to twelve magnetic poles are provided on the inner peripheral surface of the stator 10 of the bearingless rotating machine, and twelve independent single-pole windings # 1 to # 12 are provided.
Is the same as in the prior art. Rotation sensors 14A and 14B are mounted on the outer peripheral surface of the shaft 13 in a direction perpendicular to the shaft 13, and a rotating magnetic field of M poles and a rotating magnetic field of M ± 2 poles are superimposed on the single-pole windings # 1 to # 12. Applying a magnetic field to the rotor 15 to drive the rotor 15 to rotate and control the floating positioning is also the same as in the related art.

In the bearingless rotating machine of this embodiment, one terminal of each of the twelve single-pole windings # 1 to # 12 has a common neutral point 1
6 are connected to each other. And single pole winding # 1
The other terminals # 1 to # 12 are respectively connected to output terminals of power amplifiers B1 to B12 of the controller. That is, in the conventional example, as shown in FIG.
12 are connected to the balanced output terminals of the power amplifiers A1 to A12, whereas in this embodiment, one power line is connected to the power amplifiers B1 to # 12.
1 to B12.

FIG. 2 shows the circuit configuration of the output stage of the power amplifier. That is, the output circuit of each power amplifier has a circuit configuration called a half bridge composed of two power switching elements. Therefore, as compared with the conventional example shown in FIG. 5, the number of power switching elements is 12 × 2 = 24, which is halved compared to the necessity of 48 power switching elements in the conventional example. Accordingly, the number of wirings is reduced by half.

The output stage of each of the power amplifiers B1 to B12 is connected to a DC power supply E formed by rectifying and smoothing a commercial AC power supply.
Power switching elements TR1 and TR2 are connected in series, and an output is taken out from the midpoint. The switching signals are input to the gate electrodes of the power switching elements TR1 and TR2 from the control unit 22 and operate as inverter devices. Further, the DC power supply E is supplied from the power supply unit 23 to the power amplifiers B1 to B12 collectively. In addition, as a power switch element, a power transistor, a power MOS
An FET, IGBT, or the like is used.

The power amplifier of the bearingless rotating machine of the present embodiment is provided with a command value for flowing a current to each of the windings # 1 to # 12. The command value of the current is given by a calculation operation of the control device described below. In the present embodiment, the rotation drive is four poles (M = 4), and the levitation control is two poles (M−4).
2 = 2).

When the stator is rotating and magnetically levitating the rotor, information obtained by using the sensors includes a rotation speed ω, a rotation angle (electrical angle) ωt from a rotation angle sensor (not shown), a displacement sensor 14A, 14B, magnetic levitation displacements α, β, and the like. Among them, necessary information about the control system for generating the motor torque of the rotor is the rotation speed ω and the rotation angle (electrical angle) ωt. A compensation operation such as PI control is performed by a compensation circuit on the difference between the rotational speed ω detected by the sensor and the command value ω ^* , and a torque component current _Iq is calculated. Also an exciting component of the current and I _d. To convert the currents I _{d and} I _q into information for giving to the rotor, coordinate conversion is required. The currents _Ia and _Ib are obtained as _a result of the coordinate conversion given by the equation (1).

[0020]

(Equation 1)

The information required for the control system of the rotating magnetic field for giving the levitation force is the rotation angle (electrical angle) ωt and the magnetic levitation displacements α and β. Compensation calculation is performed by a compensation circuit such as PI control on the difference between the magnetic levitation displacements α and β and the command values α ^{* and} β ^* , and magnetic levitation currents Iα and Iβ are calculated. To convert the magnetic levitation currents Iα and Iβ into information for applying to the rotor, coordinate conversion is required. The arithmetic expression for coordinate conversion is given by Expression (2), and the results F _a and F _b of this coordinate conversion are obtained.

[0022]

(Equation 2)

In order to form a rotating magnetic field around the rotor, a current for forming a rotating magnetic field that generates a motor torque;
It is necessary to supply currents for forming a rotating magnetic field for magnetic levitation to the single-phase windings of the respective stators in a superimposed manner. Then, a command is given to the power amplifier to supply a required current to each phase of each stator winding. Equations (3), (4),
As shown in (5) and (6), the power amplifiers B1 to B1 of each phase
A command value to B12 is given.

[0024]

(Equation 3)

[0025]

(Equation 4)

[0026]

(Equation 5)

[0027]

(Equation 6)

It should be noted here that the sum of the current command values to each power amplifier becomes zero. This indicates that the circuit configuration can be made as shown in FIG. 1 when a current flows through each single-phase winding of the stator. That is, one of the 12-phase single-phase windings can be commonly connected to the neutral point, and the other can be unbalancedly connected to the output terminal of the corresponding power amplifier.

As shown in FIG. 3, a given current command value I ^{* is} compared with the detected current value I to form a signal to the power amplifier. An exciting current according to the current command value I ^* is supplied to each phase winding of the stator.

Although the above embodiment describes a bearingless rotating machine using a 12-phase single-phase winding, it is needless to say that the same applies to other phases. In the above embodiment, the magnetic levitation induction motor has been described. However, it goes without saying that the gist of the present invention can be similarly applied to a synchronous motor or a generator.

[0031]

According to the present invention as described above,
Since the sum of the exciting currents supplied to the single-phase windings of each phase can be made zero, there is no need to make the power amplifier a balanced type. Therefore, the required number of power switching elements and the number of wirings can be reduced by half, the manufacturing cost of the power amplifier can be reduced, and the structure of the entire equipment can be reduced in size and size.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a connection portion between a power amplifier and a stator winding according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a circuit configuration of an output stage of the power amplifier in FIG.

FIG. 3 is an explanatory diagram showing a configuration of a control system of an exciting current.

FIG. 4 is an explanatory diagram showing a connection portion between a conventional power amplifier and a stator winding.

5 is an explanatory diagram showing a circuit configuration of an output stage of the power amplifier in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Stator 13 Shaft 14A, 14B Displacement sensor 20 Control part 21 Controller 22 Power supply part # 1- # 12 Single-phase winding A1-A12, B1-B12 Power amplifier

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuki Sato 4-2-1 Motofujisawa, Fujisawa City, Kanagawa Prefecture Inside Ebara Research Institute, Ltd. (72) Inventor Tadashi Sato 4-2-2 Motofujisawa, Fujisawa City, Kanagawa Prefecture No. 1 Inside EBARA Research Institute

Claims (3)

[Claims] 1. A stator magnetic pole having a plurality of windings for applying a rotating magnetic field in which a rotating magnetic field of M poles and a rotating magnetic field of M ± 2 poles are applied to a rotor; A power amplifier that supplies a current, and a bearingless rotating machine device including a control circuit that drives the power amplifier, comprising a power amplifier corresponding to each of the plurality of windings, and an output terminal of the plurality of power amplifiers, A bearingless rotating machine device, wherein one of the windings is connected to a corresponding terminal, and the other terminal of each winding is commonly connected. 2. An output terminal of the plurality of power amplifiers,
The bearingless rotary machine according to claim 1, wherein the sum of the currents flowing into the respective windings is zero. 3. The bearingless rotary machine according to claim 2, wherein an output terminal of the power amplifier is taken from a midpoint of two power switching elements connected in series to a DC power supply. .