JPH0884491A - Motor servable as bearing - Google Patents

Abstract

PURPOSE: To obtain a motor where the motor action also serves as magnetic bearing action by employing each coil in the stator slot independently and feeding each coil with a current for generating a rotary driving field superposed by a floating position control current for magnetic bearing. CONSTITUTION: Respective coils C1, C2, C3-C12 are fed with currents having the same amplitude and different phases to generate a field for driving a rotor from the pole face 4 of a stator 1. When each coil is fed with a current of appropriate amplitude and phase, magnetic attraction takes place between the pole face 4 of the stator 1 and the rotor is thereby levitated with no contact and serves as a magnetic bearing. The rotor is pulled back when it is displaced in the X direction and the rotor is controlled to be pulled back to the original position for displacement thereof in any direction. This structure realizes the motor action for driving the rotor simultaneously with the magnetic bearing action for supporting the rotor at a target floating position with no contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing / motor,
In particular, the present invention relates to an induction motor or a synchronous motor that also serves as a bearing and has a magnetic bearing function of controlling the floating position of the rotating body in the radial direction and a motor function of rotationally driving the rotating body.

[0002]

2. Description of the Related Art Several proposals have already been made for a bearing / motor. One of them is to separate a motor drive coil and a flying position control coil as a magnetic bearing, for example, Japanese Patent Laid-Open No. 2-193547.
It is disclosed in Japanese Patent Publication No. Further, in this type of bearing-combined motor, a magnetic bearing coil and a motor coil are mounted on a common stator, or a motor stator mounted with a conventional motor coil is used to control a floating position different from that of a conventional magnetic bearing. There is one with a coil for mounting. As another method, there is a method in which a control current of the magnetic bearing and a current for generating a rotating magnetic field are superposed on a coil attached to a stator of the magnetic bearing.

[0003]

In the case where the motor drive coil and the flying position control coil are separately provided as described above, two types of coils are required for either type, which makes management of the coils difficult in manufacturing. And if the wiring is wrong, of course, normal operation cannot be expected.

Further, in a system in which a current for flying position control as a magnetic bearing and a current for generating a rotating magnetic field as a motor are superposed on a coil attached to a stator of a magnetic bearing, for example, in a secondary coil of an induction motor. There is a problem that the flow of the induced current flowing through the device becomes complicated and the control becomes complicated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an easy-to-use bearing / motor which has a simple structure and therefore does not cause a problem of malfunction.

[0006]

SUMMARY OF THE INVENTION A bearing-combined motor according to the present invention is a bearing-combined motor having both a magnetic bearing function for controlling a floating position of a rotor in a radial direction and an operation for rotationally driving the rotor. One side of each coil attached to the coil is wound in the status lot, the other side is wound on the outer side of the stator, each coil is independent, and a rotating magnetic field for rotation drive is generated in each coil. The present invention is characterized in that a control drive device is provided which causes a current having a different phase to be applied and a current for controlling the floating position of the rotating body to flow simultaneously.

Further, by adjusting the phase of the current flowing through each of the coils used for driving the motor,
A 4-pole rotating magnetic field is generated, and a 2-pole rotating magnetic field is created by adjusting the phase of the current flowing through each of the coils used for controlling the floating position, and the coils have different phases. It is characterized in that a current that is a combination of a rotating magnetic field current of four poles and a rotating magnetic field current of two poles is passed.
The rotating magnetic field for rotation drive may have two poles, and the rotating magnetic field for controlling the flying position may have four poles.

Further, although each of the coils used for driving the motor is independent, each phase coil is used for position control by adjusting the phase of the flowing current to generate a rotating magnetic field for multi-pole rotation driving. Adjusts the flowing current to create a magnetic field for controlling the levitation position, and the control drive device supplies to each of the coils a combined current of the multipole rotating magnetic field current with different phases and the levitation position control current. It is characterized by doing.

[0009]

Since the bearing-combined motor of the present invention is constructed as described above, the structure of the coil wound around the stator is simple, and the structure is the same in all status lots. Since each coil of each status lot is independent and is not connected to each other, the current for generating the rotating magnetic field for rotational driving and the current for controlling the floating position for the magnetic bearing are superposed and passed through each coil. be able to.

Therefore, by adjusting the phase and amplitude of the current flowing through each coil of the current for generating the rotating magnetic field, it is possible to easily generate the same rotating magnetic field for rotational driving as in the conventional motor, and the secondary current in the induction motor is also generated. It can be flowed as in the conventional case. Further, by adjusting the phase and amplitude of the current flowing through each coil, a magnetic field for controlling the flying position as a magnetic bearing can be easily generated.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing an arrangement of coils of a bearing / motor according to an embodiment of the present invention. On the motor stator 1, a large number of independent (not connected to each other) coils C ₁ , C ₂ , C ₃ , ... C ₁₂ are arranged. _One side of each of the coils C ₁ , C ₂ , C ₃ , ..., C ₁₂ is wound inside the status lot 2, and the other side is wound around the outside of the stator 1. In the central space 3 in the stator 1, a rotor having a magnetic material on the outer peripheral portion (not shown) is arranged.

Therefore, each coil C ₁ , C ₂ , C ₃ , ... C
By passing currents with different phases of equal amplitude to ₁₂ ,
A rotating magnetic field for rotating and driving a rotor (not shown) is applied to the stator 1.
Can be generated from the magnetic pole surface 4. Also, each coil C
_1, C _2, C _3, by passing a suitable amplitude and phase of the current to ... C _12, by the action of magnetic attraction to the rotor (not shown) from the pole face 4 of the stator 1, the non-contact levitation holds the rotor (not shown) However, it can be operated as a magnetic bearing.

1 (A), 1 (B) and 1 (C),
Shows the phase state of each coil C ₁ , C ₂ , C ₃ , ... C ₁₂ ,
(A) shows a U phase, (B) shows a V phase, and (C) shows a W phase. That is, the coil _{C 2, C 5, C 8} , C 11 constitutes a U-phase of the rotating magnetic field generating coil _{C 1, C 4, C 7} , C 10 is
The V phase for generating the rotating magnetic field is formed, and the coils C ₃ , C ₆ , C
₉ and C ₁₂ form a W phase for generating a rotating magnetic field. Further, the coils C ₁ , C ₆ , C ₇ , and C ₁₂ constitute the U phase of the magnetic field for controlling the x-direction flying position as a magnetic bearing, and the coils C ₂ , C ₃ ,
C _8, C ₉ constitute a V-phase, coil C _4, C _5,
C ₁₀ and C _{11 form} the W phase, respectively.

Then, U phase, V phase, W for generating the rotating magnetic field
By supplying currents having the same amplitude but different phases by 120 ° C. to the coils in the directions shown in FIG.
It is possible to form a rotating magnetic field for rotational drive with four poles as shown in FIG. Similarly, the flying position control coil U
A two-pole floating position control rotating magnetic field as shown in FIG. 1A can be produced by passing currents in the directions shown in the coils of the phase, V phase, and W phase.

In this state, for example, the rotor (not shown) is x
If the magnetic field of two poles is formed as shown in FIG. 1 (A) by displacing in the direction, the magnetic field of two poles and the magnetic field of four poles cancel each other on the + side of the x direction, and the magnetic attraction force weakens. -
On the side, the magnetic field of two poles and the magnetic field of four poles strengthen each other to increase the magnetic attraction force, and the rotor (not shown) is pulled back to the opposite side. This relationship is the same for the V phase shown in FIG. 1 (B) and the W phase shown in FIG. 1 (C), and it can be controlled so as to return to the original position with respect to fluctuations of the rotor (not shown) in all directions. .

Each coil C ₁ , C ₂ , C ₃ , ... C ₁₂ has
Rotating magnetic field current of 4 poles with different phases of U, V, W phases and 2
By passing a current that is the same as the current for controlling the floating position of the pole, it is possible to simultaneously perform the motor action for rotationally driving the rotor as described above and the magnetic bearing action for supporting the rotor at the target flying position in a non-contact manner. .

FIG. 5 shows a case where a two-pole rotating magnetic field is created for rotational driving and a four-pole rotating magnetic field is created for flying position control. Although FIGS. 5A and 5B show only the U phase, the V and W phases can also be shown with the phases shifted as in FIG. FIG. 5A shows a case where position control in the x direction is performed, and FIG. 5B shows a case where position control is performed in the y direction.

FIG. 2 is a block diagram of a control system of the above-mentioned bearing / motor. A current is supplied to the bearing / motor 10 from the drive controller 11 to the coils C ₁ , C ₂ , C ₃ , ... C ₁₂ . The rotation drive signal and the flying position control signal are given to the adder 12 in the drive control device. These signals are added by the adder 12 and supplied to the current controller 13. The rotation drive signal is given the target speed of the motor from the outside, and the speed detector 15 detects the rotation speed of the bearing / motor 10 and compares it with the target speed. The difference between the target speed and the speed detected by the detector is input to the speed controller 16, and the frequency of the rotation drive signal is increased or decreased so as to reduce this difference. The signal calculated by the speed controller 16 is input to the adder 12 as a rotation drive signal via the two-phase / three-phase converter 17 and the three-phase / multi-phase converter 18.

On the other hand, the flying position control signal for the magnetic bearing is sent from the displacement sensor 20 provided in the bearing / motor 10 to x.
Directional and y-direction displacements are detected and compared to the target flying position, respectively. The difference signal between the target position and the actually detected position is input to the position controller 19, a flying position control signal that reduces the difference is calculated, and the two-phase / three-phase converter 17 and the three-phase / multiphase conversion are performed. It is input to the adder 12 via the adder 18.

FIG. 3 is an explanatory view showing the coil arrangement of the bearing / motor of the second embodiment of the present invention. FIG. 3 (A),
3 (B) and 3 (C) show the coils C ₁ , C ₂ ,
The phase states of C ₃ , ... C ₁₂ are shown, (A) shows the U phase, (B) shows the V phase, and (C) shows the W phase. That is, the coils C ₅ and C ₁₁ form a U phase for generating a rotating magnetic field, and the coil C _5
3 , C ₉ constitute the V phase for generating the rotating magnetic field, and the coil C
₁ , C ₇ constitute the W phase for generating the rotating magnetic field. The coils C ₁₂ , C ₁ , C ₆ , C ₇ form a magnetic field for controlling the y-direction flying position as a magnetic bearing, and the coils C ₃ , C ₄ , C ₉ ,
C ₁₀ forms an x-direction flying position control magnetic field.

Since the coils used for driving the motor are independent as described above, a rotating magnetic field for rotating driving of multiple poles can be created by adjusting the phase of the flowing current. The coil used for flying position control is
_{C 1, C 3, C 4} , C 6, C 7, C 9, a C _10, C _12, coil C ₁ and C _12, C ₃ and C _4, C ₆ and C _7, C ₉
And C ₁₀ form a pair, respectively, to form a flying position control magnetic pole, and form a static magnetic field of four poles in total in the x and y directions.

In this case, as shown in FIG. 3, it is possible to perform rotational driving with a two-pole rotating magnetic field, and it is possible to lower the control frequency of the inverter of the current controller. Of course, the rotating magnetic field may have four poles as shown in the first embodiment,
Further, the number of poles may be increased.

FIG. 4 is a control block diagram of the bearing / motor of the second embodiment of the present invention. The configuration of this control system is almost the same as that of the first embodiment of the present invention shown in FIG. 2, but the control circuit for the flying position is different in that the two-phase to multi-phase conversion is directly performed. That is, in the present embodiment, the displacement of the rotor whose flying position is to be controlled is detected by the displacement sensor 20 in the x direction and the y direction, and compared with the target value,
The position controller 19 generates flying position control signals in the x and y directions. Then, the two-phase / multi-phase converter 14 is used to
The control signal of the current value flowing through each corresponding coil so as to form the magnetic field of the pole is input to the adder 12.

Next, an example of a circuit around the control drive device in which the rotation drive current and the flying position control current are caused to flow in an overlapping manner will be described.

FIG. 6 shows an example in which a current signal value is added by an adder and a current is supplied from an inverter circuit to a coil. Reference numeral 23 is an adder using an operational amplifier, which adds the rotation drive current signal 21 and the flying position control current signal 22 and uses an inverter 24 to output the bearing-combined motor 10 of this embodiment.
Supply current to the coil. The figure shows only one phase of the coil.

FIG. 7 shows an example of a circuit in which a drive switch and a flying position control switch are separated by using a neutral point clamp type inverter. The rotation drive signal is input to the drive switch signal terminal 26, and the floating position control switch signal terminal 27 is input.
Input the flying position control signal to. Switches 26 and 27
The rotation drive current signal and the flying position control signal are superposed by opening and closing, and a current is supplied to each coil of the bearing / motor 10 of this embodiment by using the neutral point clamp type inverter. In this circuit example, only one phase of the coil is shown.

FIG. 8 shows an example using a multiple voltage type inverter circuit using a plurality of power supply voltages. In this _{^{embodiment, V 1 +, V 2 +}} , V 3 +, ..., V 1 -, V 2 -, V 3 - ... number of switches 2 as shown in between multiple voltage and the neutral point of the
8 has been inserted. The rotation drive current signal value and the flying position control current signal value are added by a digital circuit in the preceding stage (not shown), and one of the switches 28 is closed based on the addition result, and the voltage V ₁ ⁺ , V ₂ ⁺ , ... The voltage selected from is applied to the bearing / motor 10, and the added predetermined control current is supplied to the coil. In this embodiment also, only one coil phase is shown.

FIG. 9 shows an example of a circuit in which a variable voltage source is constituted by using a thyristor or the like and is applied to a conventional inverter. Reference numeral 29 indicates a variable voltage source using a thyristor or the like. In this variable voltage source, a rotation driving current signal and a floating position control current signal are added in the preceding circuit (not shown) as in the above-mentioned circuit example. Then, the opening / closing time of the thyristor or the like is controlled based on the addition result, and a variable voltage source corresponding to the current supplied to each coil is configured. Then, the variable voltage source 29 is used to supply a current to each coil of the bearing / motor 10 of this embodiment through a conventional inverter 30.

FIG. 10 shows an example of a circuit in which two inverters are independently used for driving current supply and flying position control current supply. The rotation drive current is supplied from the inverter 31, and the flying position control current is supplied from the inverter 32 to each coil. Then, in each coil of the bearing / motor of the present embodiment, the rotation drive current and the flying position control current are superimposed. A rotary drive current signal is applied to the terminal 33 of the inverter 31, and the inverter 31 supplies a current having a predetermined frequency, current amplitude and phase to each coil based on this current signal. Similarly, the floating position control current is supplied by supplying a floating position control current signal to the terminal 34 of the inverter 32.

In the above description of the embodiment, the example in which the rotation drive current and the flying position control current are superimposed on 12 independent coils has been described, but the number of independent coils and the number of poles of the rotation drive magnetic field are described. The number of poles of the flying position control magnetic field is not limited to that in this embodiment, and should be appropriately selected according to the application of the bearing / motor. Further, the same reference numerals in the respective drawings indicate the same or corresponding parts.

[0032]

As described above, according to the bearing / motor of the present invention, the magnetic field for controlling the floating position of the rotor in the radial direction is controlled by a simple control circuit due to the simple coil arrangement structure. The bearing action and the motor action for rotationally driving the rotating body can be combined. Therefore, in the bearing-combined motor of the present invention, problems such as connection errors can be solved, the motor can be easily used, and the manufacturing cost can be reduced due to the simple structure.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an arrangement of coils of a bearing / motor according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control system of the bearing / motor.

FIG. 3 is an explanatory view showing an arrangement of coils of a bearing / motor according to a second embodiment of the present invention.

FIG. 4 is a block diagram of a control system of the bearing / motor.

FIG. 5 is an explanatory diagram showing a modified example of the first embodiment.

FIG. 6 is an explanatory view showing one circuit example of a control drive device.

FIG. 7 is an explanatory diagram showing one circuit example of the control drive device.

FIG. 8 is an explanatory diagram showing one circuit example of a control drive device.

FIG. 9 is an explanatory diagram showing a circuit example of a control drive device.

FIG. 10 is an explanatory view showing one circuit example of a control drive device.

[Explanation of symbols]

 1 Stator 2 Slot 3 Space in which rotor is arranged 4 Magnetic pole face 10 Bearing / motor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Kanemitsu 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Stock company EBARA Research Institute

Claims (9)

[Claims] 1. In a bearing-combined motor having a magnetic bearing function of controlling a floating position of a rotating body in a radial direction and an operation of rotationally driving a rotating body, each side of a coil attached to a motor stator has a status. It is wound in a lot, the other side is wound on the outer side of the stator, each coil is independent, and the currents of different phases that generate the rotating magnetic field for rotation driving in each coil and the floating position of the rotating body. A bearing-combined motor having a control drive device that simultaneously supplies a control current. 2. By adjusting the phase of the current flowing through each of the coils used for driving the motor,
By creating a rotating magnetic field for rotating the poles and adjusting the phase of the current flowing through each of the coils used for controlling the flying position, a rotating magnetic field of two poles is created, and each coil has a different phase. 2. The bearing-combined motor according to claim 1, wherein a combined current of the rotating magnetic field current of the poles and the rotating magnetic field current of the two poles is passed. 3. By adjusting the phase of the current flowing through each of the coils used for driving the motor,
By creating a rotating magnetic field for rotating the poles and adjusting the phase of the flowing current in each coil used for controlling the flying position, a rotating magnetic field of four poles is created, and each coil has a different phase. 2. The bearing-combined motor according to claim 1, wherein a combined current of the rotating magnetic field current of the poles and the rotating magnetic field current of the four poles is passed. 4. The coils used for driving the motor are independent, but by adjusting the phase of the flowing current, a rotating magnetic field for multi-pole rotation driving is created, and each coil is used for controlling the flying position. The coil creates a levitation position control magnetic field by adjusting the flowing current, and the control drive device provides a current that is a combination of a multipole rotating magnetic field current with different phases and a levitation position control current to each coil. The bearing-combined motor according to claim 1, which is supplied. 5. The control drive device adds the rotation drive current and the flying position control current in an analog manner using an adder, and supplies a current from an inverter circuit to each coil. The bearing-combined motor according to any one of claims 1 to 3. 6. The control drive device separates the rotary drive switch and the levitation position control switch by using a neutral point clamp type inverter, and outputs a combined current of the rotating magnetic field current and the levitation position control current. The bearing-combined motor according to claim 1, wherein the motor also serves as a bearing. 7. The bearing / combined bearing according to claim 1, wherein the control drive device uses a multiple voltage type inverter to supply a combined current of the rotating magnetic field current and the flying position control current. motor. 8. The control drive device comprises a variable voltage source using a thyristor or the like, and supplies a current including a rotating magnetic field current and a flying position control current from the voltage source. The bearing-combined motor according to any one of items 1 to 3. 9. The control drive device includes an inverter device for supplying a rotating magnetic field current and an inverter device for supplying a levitation position control current, and currents supplied from both of them are superimposed in each coil. The bearing-combined motor according to any one of claims 1 to 3.