JPH0886314A - Magnetic bearing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a magnetic bearing device capable of improving the degree of freedom in setting the value of a DC bias current and reducing the capacity of a current amplifier circuit as compared with a conventional one. To do. [Structure] The signal output from the control circuit 14 is discriminated by the discrimination circuit 17 in the sign of the signal.
5 is output (on the side opposite to the reference direction), and if negative, it is output on the side of the current amplification circuit 16-1 (circuit side on the reference direction side). On the side of the reference side circuit, the bias signal is directly added to the output signal of the determination circuit 17, the power is amplified by the current amplification circuit 16-1, and the current signal is supplied to the electromagnet 3-1. On the side opposite to the reference direction, the output signal of the determination circuit 17 is inverted by the signal inversion circuit 5 and then the bias signal is added, and the power is amplified by the current amplification circuit 16-2, and the current signal is supplied to the electromagnet 3-2. Supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active magnetic bearing device for stably supporting a rotary shaft in one or multiple degrees of freedom in a non-contact manner.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. FIG. 5 is a schematic diagram for explaining the relationship between the electromagnet and the rotating shaft, FIG. 6 is a block diagram of a conventional magnetic bearing device in one direction, FIG. 7 is a conceptual diagram of current flowing through the electromagnet, and FIGS. It is a figure explaining the relationship of the amount of displacement of a shaft, and the force which acts on a rotating shaft.

In FIG. 5, reference numeral 1 is a rotary shaft, and 2 is a displacement sensor for detecting the displacement of the rotary shaft 1 from a reference position.
A positive signal is generated when the rotating shaft 1 is displaced in the direction away from the displacement sensor 2, and a negative signal is generated when the rotating shaft 1 is displaced in the opposite direction. 3 is an electromagnet, which generates a magnetic attraction force to the rotating shaft 1 depending on the magnitude of the current flowing through the coil, the electromagnet 3-1 is attached to the displacement sensor 2 side (reference direction side), and the electromagnet 3-2 is It is attached to the opposite side (opposite reference direction side) of the displacement sensor 2 with the shaft interposed therebetween. Further, the air gaps X1 and X2 of the electromagnet 3-1 and the rotating shaft 1 and the electromagnet 3-2 and the rotating shaft 1 are equal to X0. The magnetic attraction force F1 generated by the electromagnet 3-1 and the magnetic attraction force F2 generated by the electromagnet 3-2 are F2.

Further, in FIG. 6, 4 is a control circuit, 5 is a signal inverting circuit, and 6 is a current amplification circuit. Control circuit 4
Is for generating a signal ΔV for stably supporting the rotary shaft 1 from the deviation between the output signal (axis displacement feedback signal) from the displacement sensor 2 shown in FIG. 5 and the target value. It is configured. The signal inverting circuit 5 also inverts the sign of the output signal ΔV of the control circuit 4. The current amplifier circuit 6 converts an input signal into a current signal, and the current amplifier circuit 6-1 adds a DC bias signal to the output signal ΔV of the control circuit 4 to obtain a signal ΔVi1.
To supply a current I1 to the coil of the electromagnet 3-1.
The current amplification circuit 6-2 inputs the signal ΔVi2 obtained by adding the DC bias signal to the output signal of the signal inverting circuit 5 and inputs the electromagnet 3
The current I2 is supplied to the -2 coil.

Next, the operation of the magnetic bearing device having the above structure will be described.

The axial displacement of the rotary shaft 1 is detected by the displacement sensor 2 and converted into an electric signal. The converted electric signal is compared with a target value and converted into an electric signal that stably supports the rotary shaft 1 by the control device 4. One of them is added with the bias signal as it is, and the other is inverted by the signal inversion circuit 5 to be biased. The signals are added, power is amplified by the current amplification circuits 3-1 and 3-2, and the current signals are supplied to the coils of the electromagnets 3-1 and 3-2. And
The electromagnets 3-1 and 3-2 each attract the rotating shaft 1 with a magnetic attraction force corresponding to the current flowing in the coil.

At this time, the DC bias current flowing through the electromagnets 3-1 and 3-2 is a component corresponding to a preset static magnetic attraction force, and the static magnetic attraction forces are equal (F1 = F2). I'm in balance. As shown in FIG. 7, the fluctuation components of the currents flowing through the electromagnets 3-1 and 3-2 are 180 ° out of phase with each other, and the change in the current flowing through the electromagnet 3-1 is due to the gap between the displacement sensor 2 and the rotary shaft 1. When the rotating shaft 1 is displaced, the amount of change in the current flowing through the electromagnet 3-2 is increased when the gap between the displacement sensor 2 and the rotating shaft 1 is reduced, so that it increases when the rotating shaft 1 is displaced. The forces F1-F2 act on the rotary shaft 1, and the position of the rotary shaft 1 is fixed and stably supported in a non-contact manner.

By the way, the current amplifier circuit 6 is usually limited in the current that can be supplied, and when the current amplifier circuit 6 receives an excessive input, it is saturated at the maximum supply current (Imax). The DC bias current is usually set to 1/2 of the maximum supply current, and the amount of change in the current becomes the maximum supply current value and zero value with positive and negative amplitudes centering on the DC bias current value, respectively. The relationship between the displacement amount of the shaft 1 and the force acting on the rotary shaft 1 is linear as shown in FIG.

However, when the value of the DC bias current is set to a value other than 1/2 of the maximum supply current, the current saturates or becomes zero faster than when it is set to 1/2 of the maximum supply current. The relationship between the displacement of the rotating shaft 1 and the force acting on the rotating shaft 1 becomes non-linear as shown in FIG. 9 and exerts a bad influence on the control, and the rigidity decreases after the current is saturated or reaches zero, and the rotating shaft 1 is stabilized. I can't support it.

[0010]

As described above,
In the conventional magnetic bearing device, the value of the DC bias current is set to 1/2 of the maximum supply current, and the capacity of the current amplifier circuit must be made larger than the required power, which is economically disadvantageous. is there. Further, when the value of the DC bias current is not set to 1/2 of the maximum supply current, the relationship between the displacement amount of the rotary shaft 1 and the force acting on the rotary shaft 1 becomes non-linear, which not only adversely affects the control, After the current is saturated or reaches zero, there is a problem that the rigidity decreases and it becomes impossible to stably support the rotating shaft 1.

The present invention has been made in view of the above problems, and it is possible to improve the degree of freedom in setting the value of the DC bias current as compared with the prior art, and to reduce the capacity of the current amplifier circuit. An object of the present invention is to provide a magnetic bearing device that can be realized.

[0012]

According to a first aspect of the present invention, there is provided a pair of first and second electromagnets installed with a rotary shaft sandwiched by an output signal of a displacement sensor for detecting the position of the rotary shaft. In an active control type magnetic bearing device which controls a flowing current and stably supports the rotating shaft in a non-contact manner, an output signal of the displacement sensor indicates zero when the rotating shaft is at a predetermined position, and the first electromagnet side. The control signal generating means for generating a control signal (ΔV) having a negative value corresponding to the deviation amount when the deviation is caused to, and a positive value corresponding to the deviation amount when the deviation toward the second electromagnet side, and the first and For the second electromagnet,
Bias current supply means for supplying a DC bias current corresponding to the maximum allowable current (Imax) that can be supplied, respectively,
Whether the control signal (ΔV) from the control signal generating means is positive or negative is determined. When the control signal (ΔV) is negative, the current supplied to the first electromagnet is decreased according to the value of the control signal (ΔV) to obtain a positive value. In this case, a means for decreasing the current supplied to the second electromagnet according to the value of the control signal (ΔV) is provided.

According to a second aspect of the present invention, an output signal of a displacement sensor for detecting the position of the rotary shaft controls the current flowing through a pair of first and second electromagnets installed with the rotary shaft interposed therebetween. In an active control type magnetic bearing device that stably supports the rotating shaft in a non-contact manner, the output signal of the displacement sensor is zero when the rotating shaft is at a predetermined position, and the amount of deviation when the rotating shaft is displaced toward the first electromagnet side. And a control signal generating means for generating a control signal (ΔV) having a negative value in accordance with the above, and a positive value in the case of deviation toward the second electromagnet side, and the first and second electromagnets, Bias current supply means for supplying a DC bias current (I0) of an arbitrary value larger than 1/2 of the maximum allowable current (Imax) that can be supplied, and signal inverting means for inverting and outputting the positive and negative of the input signal, The control signal .DELTA.V) is input, and this control signal (.DELTA.V) is compared with a value (B) obtained by subtracting a voltage corresponding to the DC bias current (I0) from a voltage corresponding to the maximum allowable current (Imax) to perform control. When the signal (ΔV) is larger, control is performed so that a current corresponding to the value of ΔV-B is added to the second electromagnet, and when the control signal (ΔV) is smaller, the control signal From the signal inverting means, there is provided first discriminating means for controlling so that a current corresponding to the value of (ΔV) is added to the first electromagnet, and an inversion signal (−ΔV) obtained by inverting the control signal (ΔV). The inverted signal (-ΔV) is input and the value (B) obtained by subtracting the voltage corresponding to the DC bias current (I0) from the voltage corresponding to the maximum allowable current (Imax) is compared, and the inverted signal ( -ΔV) is larger, the current corresponding to the value of | ΔV | -B Serial first controlled to be added to the electromagnet, in the case towards the inverted signal (- [Delta] V) is small, the inversion signal (- [Delta] V)
A second discriminating means for controlling so that a current according to the value of is added to the second electromagnet.

According to a third aspect of the present invention, an output signal of a displacement sensor for detecting the position of the rotating shaft is used to control the current flowing through the pair of first and second electromagnets installed with the rotating shaft interposed therebetween. In an active control type magnetic bearing device that stably supports the rotating shaft in a non-contact manner, the output signal of the displacement sensor is zero when the rotating shaft is at a predetermined position, and the amount of deviation when the rotating shaft is displaced toward the first electromagnet side. And a control signal generating means for generating a control signal (ΔV) having a negative value in accordance with the above, and a positive value in the case of deviation toward the second electromagnet side, and the first and second electromagnets, Bias current supply means for supplying a DC bias current (I0) of an arbitrary value smaller than 1/2 of the maximum allowable current (Imax) that can be supplied, and signal inverting means for inverting the positive / negative of the input signal and outputting the result. The control signal .DELTA.V) is input, this control signal (.DELTA.V) is compared with the voltage value (C) corresponding to the DC bias current (I0), and if the control signal (.DELTA.V) is larger, .DELTA.V-C Is controlled to be added to the second electromagnet, and when the control signal (ΔV) is smaller, the current corresponding to the value of the control signal (ΔV) is changed to the first electromagnet. And a reverse signal (−) that is the reverse of the control signal (ΔV).
.DELTA.V) is input from the signal inverting means, the inverted signal (-.DELTA.V) is compared with the voltage value (C) corresponding to the DC bias current (I0), and the inverted signal (-.DELTA.V) is larger. In this case, the current corresponding to the value of | ΔV | -C is controlled to be added to the first electromagnet, and the inverted signal (-Δ
When V) is smaller, a second determining means is provided for controlling so that a current corresponding to the value of the inversion signal (−ΔV) is added to the second electromagnet.

According to a fourth aspect of the present invention, an output signal of a displacement sensor for detecting the position of the rotary shaft controls the current flowing through a pair of first and second electromagnets installed with the rotary shaft interposed therebetween. In an active control type magnetic bearing device that stably supports the rotating shaft in a non-contact manner, the output signal of the displacement sensor is zero when the rotating shaft is at a predetermined position, and the amount of deviation when the rotating shaft is displaced toward the first electromagnet side. And a control signal generating means for generating a control signal (ΔV) having a negative value corresponding to the second electromagnet and a positive value corresponding to the amount of deviation when deviated to the second electromagnet side, and a DC bias to the control signal (ΔV). A first addition signal (ΔVi1) is generated by adding a voltage corresponding to the current, and the maximum allowable current (I) that can be supplied to the first electromagnet is generated.
A first bias current supply means for supplying a DC bias current having an arbitrary value larger than ½ of (max) and the control signal (ΔV) are input, the positive and negative are inverted, and the inverted signal (−Δ) is obtained.
V) and a signal inversion means for outputting the inversion signal (-Δ
V) is added with a voltage corresponding to the DC bias current to generate a second addition signal (ΔVi2), which is larger than 1/2 of the maximum allowable current (Imax) that can be supplied to the second electromagnet. Second bias current supply means for supplying a DC bias current having a value, and the first addition signal (ΔVi1)
And a maximum voltage (Vimax) corresponding to the maximum allowable current (Imax) are compared, and a first addition signal (ΔVi1)
Is larger, the control is performed so that a current according to the value of ΔVi1-Vimax is added to the second electromagnet,
When the addition signal (ΔVi1) is smaller than the first addition signal (ΔVi1), the first determination means for controlling so that the current according to the value of the first addition signal (ΔVi1) is supplied to the first electromagnet; 2 addition signal (ΔVi2) and the maximum allowable current (I
The maximum voltage (Vimax) corresponding to (max) is compared, and if the second addition signal (ΔVi2) is larger, ΔVi
The current according to the value of 2-Vimax is controlled to be added to the first electromagnet, and when the second addition signal (ΔVi2) is smaller, the value of the second addition signal (ΔVi2) is changed to the value of the second addition signal (ΔVi2). And a second discriminating means for controlling so that the corresponding electric current is supplied to the second electromagnet.

According to a fifth aspect of the present invention, the current flowing through the pair of first and second electromagnets installed with the rotary shaft interposed therebetween is controlled by the output signal of the displacement sensor that detects the position of the rotary shaft. In an active control type magnetic bearing device that stably supports the rotating shaft in a non-contact manner, the output signal of the displacement sensor is zero when the rotating shaft is at a predetermined position, and the amount of deviation when the rotating shaft is displaced toward the first electromagnet side. And a control signal generating means for generating a control signal (ΔV) having a negative value corresponding to the second electromagnet and a positive value corresponding to the amount of deviation when deviated to the second electromagnet side, and a DC bias to the control signal (ΔV). A first addition signal (ΔVi1) is generated by adding the voltage corresponding to the current, and the maximum allowable current of 1 that can be supplied to the first electromagnet is 1
First bias current supply means for supplying a DC bias current of an arbitrary value smaller than / 2, and the control signal (ΔV)
And a signal inverting means for inverting the positive and negative and outputting an inversion signal (-ΔV), and a second addition signal (ΔVi2) obtained by adding a voltage corresponding to a DC bias current to the inversion signal (-ΔV). For generating a DC bias current of any value smaller than 1/2 of the maximum allowable current that can be supplied to the second electromagnet, and the first addition signal (ΔVi1). ) Has a negative polarity, control is performed so that a current corresponding to the absolute value of the first addition signal (ΔVi1) is added to the second electromagnet, and the first addition signal (ΔVi1) has a positive polarity. In this case, the first addition signal (Δ
Vi1) a first discriminating means for controlling a current to be supplied to the first electromagnet, and a second addition signal when the second addition signal (ΔVi2) has a negative polarity. A current corresponding to the absolute value of (ΔVi2) is controlled to be added to the first electromagnet, and a second addition signal (ΔVi2) is obtained.
Is positive, a second determination means is provided for controlling so that a current corresponding to the value of the second addition signal (ΔVi2) is supplied to the second electromagnet. .

[0017]

In the magnetic bearing device of the present invention having the above-described structure, the degree of freedom in setting the value of the DC bias current can be improved and the capacity of the current amplifier circuit can be reduced as compared with the conventional one. it can.

[0018]

The details of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a block structure for one direction of a magnetic bearing device according to an embodiment of the present invention, and FIG. 2 is a view for explaining the operation in this embodiment. In addition,
The configurations of the electromagnet 3, the rotary shaft 1 and the like are the same as those of the magnetic bearing device shown in FIG.

In FIG. 1, 14 is a control circuit, 15 is a signal inversion circuit, 16 is a current amplification circuit, 17 is a discrimination circuit, 3
Is an electromagnet.

The control circuit 14 uses the deviation ΔV between the output signal (axis displacement feedback signal) from the displacement sensor 2 and the target value shown in FIG.
And is composed of digital or analog circuits. That is, when the rotating shaft 1 is at a predetermined position and the deviation between the output signal from the displacement sensor 2 and the target value is zero, the rotating shaft 1 is separated from the displacement sensor 2 (reference direction side electromagnet 3-1). When displaced in the direction, a positive signal corresponding to the displacement amount is generated, and when displaced in the opposite direction, a negative signal corresponding to the displacement amount is generated.

Further, the signal inverting circuit 15 includes a control circuit 14
Of the output signal ΔV is inverted, and the discrimination circuit 17 switches the output direction according to the sign of the output signal ΔV of the control circuit 14.

Further, the current amplification circuit 16 converts an input signal into a current signal, and the current amplification circuit 16-
1 receives the signal ΔVi1 obtained by adding the DC bias signal to the output signal ΔV1 of the determination circuit 17 and supplies the current I1 to the coil of the electromagnet 3-1. The current amplification circuit 16-2 outputs the output signal ΔV2 of the signal inverting circuit 15 The signal ΔVi2 obtained by adding the DC bias signal is input, and the current I2 is supplied to the coil of the electromagnet 3-2.

Next, the operation of the magnetic bearing device of this embodiment having the above structure will be described.

As shown in FIG. 5, the axial displacement of the rotary shaft 1 is detected by the displacement sensor 2 and converted into an electric signal.

The converted electric signal is compared with a target value and converted by the control circuit 14 into an electric signal for stably supporting the rotary shaft 1 and output. The sign of the signal output from the control circuit 14 is determined by the determination circuit 17, and if the signal is positive, the signal is output to the signal inverting circuit 15 side (counter reference direction side),
If negative, the current amplification circuit 16-1 side (reference direction side circuit side)
Is output to.

On the reference direction side circuit side, the bias signal is directly added to the output signal of the discriminating circuit 17, the power is amplified by the current amplifying circuit 16-1, and the electromagnet 3 is used as the current signal.
The electromagnet 3-1 is supplied to the -1 coil, and the electromagnet 3-1 attracts the rotating shaft 1 by a magnetic attraction force corresponding to the current flowing in the coil.

On the other hand, on the side opposite to the reference direction, the output signal of the discriminating circuit 17 is positively / negatively inverted by the signal inverting circuit 5, the bias signal is added, the power is amplified by the current amplifying circuit 16-2, and it is converted into a current signal. The electromagnet 3-2 is supplied to the coil of the electromagnet 3-2, and the electromagnet attracts the rotating shaft 1 with a magnetic attraction force corresponding to the current flowing through the coil.

The bias signal is the maximum allowable current (Ima) that can be supplied from the current amplification circuit 16 to the electromagnet 3.
x) is set. That is, the DC component of the current flowing through the electromagnets 3-1 and 3-2 is set to the saturation current of the current amplification circuit 16 with a component corresponding to the static magnetic attraction force, and each of the electromagnets 3-1 and 3-2. Since the DC bias currents flowing in the two are equal, the respective static magnetic attraction forces are equal (F1 = F2) and balanced.

The fluctuation components of the currents flowing through the electromagnets 3-1 and 3-2 are 180 ° out of phase with each other as shown in FIG.
And the change amount of the current flowing through the electromagnet 3-2 is reduced only when the gap between the rotary shaft 1 and the rotary shaft 1 decreases.
And it is designed to decrease only when the gap of the rotary shaft 1 increases. Therefore, since the force always acts in the direction opposite to the displaced direction, the position of the rotary shaft 1 is fixed and stably supported without contact.

On the other hand, the respective electromagnets 3-1 and 3-
The current flowing in 2 can be changed from Imax to zero in one case while the other is fixed in any case. Therefore, the relationship between the displacement of rotary shaft 1 and the force acting on rotary shaft 1 is linear as shown in FIG. And the electromagnets 3-1 and 3-2 have Imax
Since the above current is not required, the capacity of the current amplification circuit 16 can be minimized.

Next, another embodiment will be described.

FIG. 3 shows the structure of a magnetic bearing device of another embodiment. In FIG. 3, reference numeral 18 is a discriminating circuit,
The reference direction side determination circuit 18-1 is directly connected to the control circuit 14, and the counter reference direction side determination circuit 18-2 is connected to the signal inverting circuit 15. In this embodiment, the DC bias current (I0) is the maximum allowable current (Ima).
It is set to an arbitrary value larger than 1/2 of x), and a voltage according to this set value is added to the output side of the discrimination circuit 18.

The discriminating circuit 18-1 on the reference direction side receives the output signal ΔV of the control circuit 14, and its magnitude corresponds to a value obtained by subtracting the DC bias current (I0) from the maximum allowable current (Imax). If it is larger than the voltage value (B),
The value of ΔV-B is added to the anti-reference direction side circuit, and when it is smaller, it is output as it is to the reference direction side circuit.

On the other hand, the discrimination circuit 18-2 on the side opposite to the reference direction
When the input signal (−ΔV) from the signal inverting circuit 5 is larger than B, the value of | −ΔV | −B is added to the reference direction side circuit, and when it is smaller, it is directly to the anti-reference direction side circuit. Output.

In the present embodiment configured as described above, the value of the DC bias current flowing through the electromagnet 3 can be arbitrarily set, and the amount of displacement of the rotary shaft 1 and the force acting on the rotary shaft 1 can be set. Can be linear, and the rotating shaft 1 can be stably controlled.

In the above embodiment, the DC bias current (I0) is set to any value larger than 1/2 of the maximum allowable current (Imax), but the DC bias current (I0) is set.
Can be set to any value smaller than 1/2 of the maximum allowable current (Imax). In this case, the determination circuit 18-1 on the reference direction side compares the output signal ΔV of the control circuit 14 with the voltage value (C) corresponding to the DC bias current (I 0), and when the output signal ΔV is larger, , ΔV-C is added to the circuit on the side opposite the reference direction, and when it is smaller, it is output to the circuit on the reference direction side as it is. At the same time, when the input signal (−ΔV) from the signal inverting circuit 5 is larger than C, the discrimination circuit 18-2 on the side opposite to the reference direction,
The value of |-[Delta] V | -C is added to the reference direction side circuit, and when it is smaller, it is output to the anti-reference direction side circuit as it is.

Next, still another embodiment will be described.

FIG. 4 shows a main structure of a magnetic bearing device according to still another embodiment. In FIG. 4, reference numeral 19 is a discriminating circuit, and the discriminating circuit 19-1 on the reference direction side is a control circuit 14. Is provided after the adder that adds the voltage corresponding to the DC bias signal to the output signal ΔV of 1 to generate the addition signal ΔVi1, and before the current amplification circuit 16-1. The discriminating circuit 19-2 is a post-stage of the adder that adds a voltage corresponding to the DC bias signal to the signal inverted by the signal inverting circuit 15 to generate the addition signal ΔVi2, and is a pre-stage of the current amplifying circuit 16-2. It is provided in. Further, in this embodiment, the DC bias current is set to an arbitrary value larger than 1/2 of the maximum allowable current (Imax).

The discrimination circuit 19-1 on the reference direction side compares the addition signal ΔVi1 with the voltage (Vimax) corresponding to the maximum allowable current (Imax), and when the addition signal ΔVi1 is larger, ΔVi1-. The value of Vimax is added to the anti-reference direction side circuit, and when the addition signal ΔVi1 is smaller, it is output to the reference direction side circuit as it is.

On the other hand, the discrimination circuit 19-2 on the side opposite to the reference direction
Compares the addition signal ΔVi2 with a voltage (Vimax) corresponding to the maximum allowable current (Imax), and adds the addition signal ΔVi2.
Is larger, the value of .DELTA.Vi2-Vimax is added to the reference direction side circuit, and when the added signal .DELTA.Vi2 is smaller, it is output to the anti-reference direction side circuit as it is.

In the present embodiment configured as described above, the value of the DC bias current flowing through the electromagnet 3 can be set arbitrarily, and the displacement amount of the rotary shaft 1 and the force acting on the rotary shaft 1 can be set. Can be linear, and the rotating shaft 1 can be stably controlled.

Although the DC bias current is set to an arbitrary value larger than 1/2 of the maximum allowable current (Imax) in the above embodiment, the DC bias current is set to 1/2 of the maximum allowable current (Imax). It can be set to any smaller value.

In this case, the reference direction side discrimination circuit 19-1
Is the addition signal ΔVi1 when the addition signal ΔVi1 has a negative polarity.
The absolute value of Vi1 is added to the anti-reference direction side circuit, and when the addition signal ΔVi1 has a positive polarity, it is directly output to the reference direction side circuit. At the same time, the determination circuit 19-2 on the anti-reference direction side adds the absolute value of the addition signal ΔVi2 to the anti-reference direction side circuit when the addition signal ΔVi2 has a negative polarity, and when the addition signal ΔVi2 has a positive polarity. Is configured to output to the reference direction side circuit as it is.

[0045]

As described above, according to the present invention,
The degree of freedom in setting the value of the DC bias current can be improved as compared with the related art, and the capacity of the current amplifier circuit can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a block configuration for one direction of a magnetic bearing device according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the magnetic bearing device of FIG.

FIG. 3 is a diagram showing a block configuration for one direction of a magnetic bearing device according to another embodiment.

FIG. 4 is a diagram showing a block configuration for one direction of a magnetic bearing device according to another embodiment.

FIG. 5 is a diagram showing a relationship between an electromagnet of a magnetic bearing device, a rotary shaft, and a displacement sensor.

FIG. 6 is a diagram showing a block configuration of a conventional magnetic bearing device for one direction.

FIG. 7 is a view for explaining the operation of the magnetic bearing device of FIG.

FIG. 8 is a diagram for explaining a relationship between a displacement amount of a rotating shaft and a force acting on the rotating shaft.

FIG. 9 is a diagram for explaining a relationship between a displacement amount of a rotating shaft and a force acting on the rotating shaft.

[Explanation of symbols]

 3-1 ... Reference direction side electromagnet 3-2 ... Anti-reference direction side electromagnet 14 Control circuit 15 Signal inversion circuit 16-1 Reference direction side current amplification circuit 16-2 Anti-reference direction side current amplification circuit 17 Discrimination circuit

Front Page Continuation (72) Kenichi Matsuo Inventor Kenichi Matsuo 2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi Kanagawa Stock company Toshiba Keihin office

Claims (5)

[Claims] 1. An output signal of a displacement sensor for detecting the position of a rotary shaft controls currents flowing through a pair of first and second electromagnets installed with the rotary shaft sandwiched therebetween, so that the rotary shaft does not contact. In an active control type magnetic bearing device that stably supports, from the output signal of the displacement sensor, zero when the rotation shaft is at a predetermined position, a negative value according to the amount of deviation when the rotation shaft is displaced to the first electromagnet side, Control signal generating means for generating a positive control signal (ΔV) according to the amount of deviation when the second electromagnet is deviated, and the maximum allowable current that can be supplied to each of the first and second electromagnets. Bias current supplying means for supplying a DC bias current corresponding to (Imax) and positive or negative of the control signal (ΔV) from the control signal generating means are discriminated. If negative, supply to the first electromagnet. The current concerned The control signal (ΔV) is decreased according to the value of the control signal (ΔV), and in the case of a positive value, the current supplied to the second electromagnet is decreased according to the value of the control signal (ΔV). Magnetic bearing device. 2. The output signal of a displacement sensor for detecting the position of the rotary shaft controls the current flowing through a pair of first and second electromagnets installed with the rotary shaft sandwiched between them so that the rotary shaft does not contact. In an active control type magnetic bearing device that stably supports, from the output signal of the displacement sensor, zero when the rotation shaft is at a predetermined position, a negative value according to the amount of deviation when the rotation shaft is displaced to the first electromagnet side, Control signal generating means for generating a positive control signal (ΔV) according to the amount of deviation when the second electromagnet is deviated, and the maximum allowable current that can be supplied to each of the first and second electromagnets. Bias current supply means for supplying a DC bias current (I0) of any value larger than 1/2 of (Imax), signal inverting means for inverting the positive / negative of an input signal and outputting the same, and the control signal (ΔV) Enter this Control signal (ΔV)
And the value (B) obtained by subtracting the voltage corresponding to the DC bias current (I0) from the voltage corresponding to the maximum allowable current (Imax) are compared, and when the control signal (ΔV) is larger, The current corresponding to the value of ΔV-B is controlled to be added to the second electromagnet, and when the control signal (ΔV) is smaller, the current corresponding to the value of the control signal (ΔV) is set to the second value. The first discriminating means for controlling the addition to the electromagnet of No. 1 and the inverted signal (-ΔV) obtained by inverting the control signal (ΔV) are inputted from the signal inverting means, and the inverted signal (-ΔV) is inputted.
And the value (B) obtained by subtracting the voltage corresponding to the DC bias current (I0) from the voltage corresponding to the maximum allowable current (Imax) are compared, and when the inverted signal (-ΔV) is larger, , | ΔV | -B is controlled so that a current corresponding to the value of the inverted signal (-ΔV) is added to the first electromagnet. A second electric current which controls so that the electric current is added to the second electromagnet.
And a magnetic bearing device. 3. An output signal of a displacement sensor for detecting the position of the rotary shaft controls currents flowing through a pair of first and second electromagnets installed with the rotary shaft sandwiched therebetween to bring the rotary shaft into non-contact. In an active control type magnetic bearing device that stably supports, from the output signal of the displacement sensor, zero when the rotation shaft is at a predetermined position, a negative value according to the amount of deviation when the rotation shaft is displaced to the first electromagnet side, Control signal generating means for generating a positive control signal (ΔV) according to the amount of deviation when the second electromagnet is deviated, and the maximum allowable current that can be supplied to each of the first and second electromagnets. Bias current supply means for supplying a DC bias current (I0) of an arbitrary value smaller than 1/2 of (Imax), signal inverting means for inverting the positive / negative of an input signal and outputting the same, and the control signal (ΔV) Enter this Control signal (ΔV)
And the voltage value (C) corresponding to the DC bias current (I0) are compared, and when the control signal (ΔV) is larger, a current corresponding to the value of ΔV-C is applied to the second electromagnet. And a control signal (ΔV) that is smaller than the control signal (ΔV), a current corresponding to the value of the control signal (ΔV) is controlled to be added to the first electromagnet. And an inverted signal (-ΔV) obtained by inverting the control signal (ΔV) from the signal inverting means, and the inverted signal (-ΔV).
And the voltage value (C) corresponding to the DC bias current (I0) are compared, and when the inverted signal (-ΔV) is larger, the current corresponding to the value of | ΔV | -C is When the inverted signal (−ΔV) is smaller, the current corresponding to the value of the inverted signal (−ΔV) is controlled to be added to the second electromagnet. Second
And a magnetic bearing device. 4. The output signal of a displacement sensor for detecting the position of the rotary shaft controls the current flowing through a pair of first and second electromagnets installed with the rotary shaft sandwiched therebetween to bring the rotary shaft into non-contact. In an active control type magnetic bearing device that stably supports, from the output signal of the displacement sensor, zero when the rotation shaft is at a predetermined position, a negative value according to the amount of deviation when the rotation shaft is displaced to the first electromagnet side, Control signal generating means for generating a control signal (ΔV) having a positive value according to the amount of deviation when the second electromagnet is displaced, and a voltage corresponding to a DC bias current is added to the control signal (ΔV). Generate a first addition signal (ΔVi1),
The maximum allowable current (Imax) that can be supplied to the first electromagnet
), A first bias current supply means for supplying a DC bias current having an arbitrary value larger than 1/2, and the control signal (ΔV) are input, the positive and negative are inverted and an inverted signal (−ΔV) is output. A signal inversion means and a second addition signal (ΔVi2) in which a voltage corresponding to a DC bias current is added to the inversion signal (−ΔV) to generate a maximum allowable current () that can be supplied to the second electromagnet. I
second bias current supply means for supplying a DC bias current of an arbitrary value larger than ½ of (max), the first addition signal (ΔVi1), and the maximum voltage corresponding to the maximum allowable current (Imax). (Vimax), and if the first addition signal (ΔVi1) is larger,
The current corresponding to the value of ΔVi1-Vimax is controlled to be added to the second electromagnet, and the first addition signal (ΔVi
If 1) is smaller, the first addition signal (ΔVi
1) determining means for controlling a current according to the value of 1) to be supplied to the first electromagnet, the second addition signal (ΔVi2), and a maximum corresponding to the maximum allowable current (Imax) The voltage (Vimax) is compared, and when the second addition signal (ΔVi2) is larger,
The current corresponding to the value of ΔVi2-Vimax is controlled to be added to the first electromagnet, and the second addition signal (ΔVi
If 2) is smaller, the second addition signal (ΔVi
2. A magnetic bearing device comprising: a second determining unit that controls so that a current according to the value of 2) is supplied to the second electromagnet. 5. The output signal of a displacement sensor that detects the position of the rotating shaft controls the current flowing through a pair of first and second electromagnets that are installed with the rotating shaft interposed therebetween, so that the rotating shaft does not contact. In an active control type magnetic bearing device that stably supports, from the output signal of the displacement sensor, zero when the rotation shaft is at a predetermined position, a negative value according to the amount of deviation when the rotation shaft is displaced to the first electromagnet side, Control signal generating means for generating a control signal (ΔV) having a positive value according to the amount of deviation when the second electromagnet is displaced, and a voltage corresponding to a DC bias current is added to the control signal (ΔV). Generate a first addition signal (ΔVi1),
1/2 of the maximum allowable current that can be supplied to the first electromagnet
First for supplying a DC bias current of any smaller value
Bias current supply means, signal inversion means for inputting the control signal (ΔV), inverting positive and negative and outputting an inversion signal (−ΔV), and the inversion signal (−ΔV) corresponding to a DC bias current. Of the maximum allowable current that can be supplied to the second electromagnet by generating a second added signal (ΔVi2)
Second bias current supply means for supplying a DC bias current of an arbitrary value smaller than / 2; and when the first addition signal (ΔVi1) has a negative polarity,
A current corresponding to the absolute value of the first addition signal (ΔVi1) is controlled to be added to the second electromagnet, and when the first addition signal (ΔVi1) has a positive polarity, the first addition signal When the first determination unit that controls so that a current according to the value of (ΔVi1) is supplied to the first electromagnet, and the second addition signal (ΔVi2) has a negative polarity,
A current corresponding to the absolute value of the second addition signal (ΔVi2) is controlled to be added to the first electromagnet, and when the second addition signal (ΔVi2) has a positive polarity, the second addition signal A magnetic bearing device comprising: a second determination unit that controls a current according to the value of (ΔVi2) to be supplied to the second electromagnet.