JPH07293563A - Drive control device for rotating device supporting rotor on magnetic bearing - Google Patents

Abstract

PURPOSE:To provide a drive control device for a rotation device supporting a rotor on magnetic bearings, which allows regenerative electric power to be consumed by one regenerative electric power consumption circuit employing a DC-DC converter if commercial, power has stopped or when the brake is arbitrarily applied, and furthermore enables magnetic bearing control to be continued without using a battery. CONSTITUTION:In the drive control device for a rotation device movably supporting a rotor with magnetic bearings, electric power is so constituted as to be fed to a magnetic bearing controlling power supply section 16 from a commercial power supply 10 via a power supply switch 28, the power supply switch 28 is cut off when the brake is applied to the rotor, concurrently regenerative electric power generated by an AC motor 27 is converted into DC current via an inverter 26, and furthermore, DC current is controlled to be intended voltage via a DC-DC converter 29, so that it is fed to the magnetic bearing controlling power supply section 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a rotating device, such as a turbo molecular pump, which supports a rotating body with magnetic bearings and rotates the rotating body at a high speed.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing the configuration of a conventional drive control device for a turbo molecular pump. In the figure, 1
0 is a commercial power supply, 11 is a power failure detection circuit, 12 is a converter circuit, 13 is a diode OR, 14 is a battery protection circuit, 15 is a battery, 16 is a magnetic bearing control power supply unit, 17 is a control circuit, 18 is a rectifier, Reference numeral 19 is a PWM (pulse width modulation) drive circuit, 20 is a transformer, 21 is a smoothing section, 22 is a voltage control circuit, 23 is a regenerative power consumption control circuit, 24 is a regenerative brake circuit, 25 is a pump drive control section, and 26 is an inverter. Reference numerals 27 and 27 are AC motors for driving a rotating body supported by magnetic bearings (not shown).

In the drive control device having the above structure, the AC from the commercial power supply 10 is converted into DC by the converter circuit 12 and passes through the diode OR13 to control the magnetic bearing control power supply unit 1.
6 is supplied. An electric current for operation and control is supplied from the magnetic bearing control power supply unit 16 to a magnetic bearing (not shown). On the other hand, the alternating current from the commercial power source 10 is converted into a direct current by the rectifier 18, and the direct current is converted into a pulsed direct current by the PWM drive circuit 19 controlled by the pump drive control section 25 and supplied to the primary side of the transformer 20. It is supplied to the inverter 26 from the secondary side of the transformer 20 through the smoothing section 21. The pump drive control unit 25 controls the inverter 26, supplies alternating current of a desired frequency to the alternating current motor, and rotates the alternating current motor 27 at a desired rotation speed (usually, a high speed rotation speed of 10,000 or more).

When the commercial power source 10 is present and the pump rated operation is constantly entered into the stop operation, the pump drive control unit 25 decelerates the AC motor 27 according to the V / f pattern in response to the stop command ST. Regenerative voltage
A voltage control circuit that monitors the upper limit of the regenerative voltage that outputs a signal that performs protection control from the breakdown voltage of the components, and that monitors the lower limit of the regenerative voltage that outputs a signal that does not stop the excitation voltage for maintaining regenerative braking. 22 and the regenerative braking circuit 24 that consumes the regenerative voltage realize the braking.

Further, during a power failure in which the commercial power supply is cut off during the rated operation of the turbo molecular pump, the magnetic bearing cannot be controlled, the rotor touches down, and the rotational energy and mass of the rotor are all for touchdown. The bearing is burdened and the durability of the bearing is extremely worn and deteriorated. Therefore, touchdown at high rotation is not desirable. Therefore, in the drive control device having the above-described configuration, the detection signal of the power failure detection circuit 11 is input to the control circuit 17 to shift to the stop operation, but the magnetic bearing control power supply unit 16 uses the output from the converter circuit 12 and the battery voltage. Since they are connected by the diode OR13, the input voltage of the magnetic bearing control power supply unit 16 is not interrupted, so that the magnetic bearing control is continued.

Although the purpose of consuming the regenerative power from the AC motor 27 is the same, a DC-DC converter is used as a substitute for the regenerative brake circuit 24 to eliminate the need for a battery, and the regenerative power is used to control the magnetic bearing. A method of returning to 16 to improve economic efficiency is also conceivable. However,
In this case, it is effective only during a power failure, and when there is a commercial power source, the DC-DC converter is in a no-load state and cannot consume power, so that the former means is used to consume regenerative power.

[0007]

The above-mentioned conventional battery backup method requires a battery, which causes a problem of cost increase. In addition, even for those that do not require a battery, the regenerative braking circuit and the DC-DC converter must be mounted in one magnetic bearing control device, which leads to an increase in cost and the size of the circuit increases as the circuit becomes complicated. Also, using regenerative power consumption in normal use and a regenerative braking circuit, and using a DC-DC converter during a power failure to selectively use the regenerative power consumption means has many disadvantages in production and control. .

The present invention has been made in view of the above-mentioned points, and since the durability has been improved by the recent improvement of the bearing technology, the bearing can be mounted without being aware of wear deterioration due to touchdown at a middle rotation speed. DC-DC regenerative power when it can be used or when braking is performed at power failure
An object of the present invention is to provide a drive control device for a rotating device that supports a rotating body by a magnetic bearing that can be consumed by one regenerative power consumption circuit that uses a converter and that can continue magnetic bearing control without using a battery. To do.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a magnetic bearing which converts AC from a commercial power source into DC through a converter circuit and supplies driving and control power to the magnetic bearing. The AC power from the commercial power supply is converted into a direct current of a desired voltage through a rectifier and the like, and the direct current is further converted into an alternating current of a desired frequency through an inverter to drive the rotating body. In a drive control device for a rotating device that supports a rotating body with a magnetic bearing configured to supply to an AC motor, the power source for controlling the magnetic bearing is supplied with power from a commercial power source or a converter via a power switch. The power source switch is cut off when the rotating body is braked, the regenerative power generated by the AC motor is converted into DC through an inverter, and the DC is further converted into DC-D.
It is characterized in that the voltage is controlled to a desired voltage via the C converter and is supplied to the magnetic bearing control power supply unit.

[0010]

According to the present invention, by adopting the above-mentioned structure, the power switch is cut off when the rotating body is braked, the power supply from the commercial power supply or the converter circuit to the magnetic bearing control power supply unit is cut off, and the AC motor generates the power. The regenerative power is converted into direct current through the inverter, and the direct current is further controlled through the DC-DC converter to a desired voltage, which is supplied to the magnetic bearing control power supply unit. When braking is performed, it becomes possible to consume the regenerative electric power by one regenerative electric power consumption circuit using the DC-DC converter and continue the magnetic bearing control without using the battery.
Further, since the durability has been improved by the recent improvement of the bearing technology, such a thing can be realized by using a bearing that does not deteriorate due to wear even if it touches down at a medium rotation speed of the rotating body.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a drive control device for a rotating device (a turbo molecular pump in this embodiment) that supports a rotating body with a magnetic bearing according to the present invention. In the figure, the parts denoted by the same reference numerals and numbers as those in FIG. In this drive control device, as shown in FIG.
As shown in, a normally closed power switch 28 is connected in series between the commercial power supply 10 and the converter circuit 12,
A DC-DC converter 29 is connected to the output side of the smoothing unit 21, and the output of the DC-DC converter 29 is connected to the magnetic bearing control power supply unit 16 via the diode OR13.

When the power failure detection circuit 11 detects a power failure of the commercial power supply 10, the power switch 28 is opened by the power failure detection circuit 11 and the control circuit 17 receives a stop command ST from the outside.
Is configured to open when is entered.

In the drive control device having the above-mentioned configuration, when the commercial power source 10 has a power failure or when there is a stop command ST from the outside, the power failure detection circuit 11 or the control circuit 17 opens the power switch 28 and shuts off the commercial power source 10. To be done. On the other hand, the AC motor 27 is decelerated by the V / f pattern braking control of the pump drive controller 25. At this time, the AC generator converts the regenerated electric power into a direct current through the inverter, and the converted direct current voltage is passed through the DC-DC converter 29 and the diode OR13 as a desired voltage to the magnetic bearing control power supply unit 16 Supply to. That is, since the magnetic bearing control power supply unit 16 is supplied with the regenerative power from the AC motor, the magnetic bearing control is continued.

By configuring the drive control device as described above, the AC motor 27 is provided in the magnetic bearing control power supply unit 16.
Is not supplied until the power is completely stopped, and when the regenerative power becomes small, the power supplied to the magnetic bearing control power supply unit 16 also becomes small, and magnetic bearing control cannot be performed. However, recent improvements in bearing technology have improved durability. However, a rotating body (a rotor of a turbo molecular pump in the embodiment) supported by magnetic bearings has been developed in which wear deterioration does not occur even if touchdown is performed at a medium rotation speed. If such a bearing is used as a touchdown bearing, even if the drive control device is configured as described above, it is possible to sufficiently deal with durability and the like.

In the above embodiment, the power switch 28
Is inserted between the commercial power supply 10 and the converter circuit 12, the power switch 28 may of course be inserted between the converter circuit 12 and the diode OR13.

[0016]

As described above, according to the present invention, the following excellent effects can be expected. At the time of braking the rotating body, the power switch is cut off to cut off the power supply from the commercial power supply or the converter circuit to the magnetic bearing control power supply unit, and the regenerative power generated by the AC motor is converted into DC through the inverter. Since the direct current is controlled to a desired voltage via the DC-DC converter and is supplied to the magnetic bearing control power supply unit, the DC-DC converter is used for the regenerative power during the power failure and when arbitrarily braking. It becomes possible to consume with one regenerative power consumption circuit and to continue the magnetic bearing control without using a battery.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a drive control device of a rotating device that supports a rotating body by a magnetic bearing of the present invention.

FIG. 2 is a block diagram showing a configuration of a drive control device for a conventional turbo molecular pump.

[Explanation of symbols]

 10 Commercial Power Supply 11 Power Failure Detection Circuit 12 Converter Circuit 13 Diode OR 14 Battery Protection Circuit 15 Battery 16 Magnetic Bearing Control Power Supply Section 17 Control Circuit 18 Rectifier 19 PWM Drive Circuit 20 Transformer 21 Smoothing Section 22 Voltage Control Circuit 23 Regenerative Power Consumption Control Circuit 24 Regenerative Brake Circuit 25 Pump Drive Control Unit 26 Inverter 27 AC Motor 28 Power Switch 29 DC-DC Converter

Claims (1)

[Claims] 1. An alternating current from a commercial power supply is converted into a direct current through a converter circuit, and is supplied to a magnetic bearing control power supply section for supplying driving and control power to a magnetic bearing, and
An alternating current from the commercial power source is converted into a direct current of a desired voltage through a rectifier or the like, the direct current is further converted into an alternating current of a desired frequency through an inverter, and an alternating current for driving a rotating body supported by the magnetic bearing. In a drive control device for a rotating device that supports a rotating body with a magnetic bearing configured to supply to a motor, power is supplied from the commercial power supply or the converter to a power supply unit for controlling the magnetic bearing through a power switch. The power switch is cut off when the rotating body is braked, regenerative power generated by the AC motor is converted into DC through the inverter, and the DC is further converted into DC.
A drive control device for a rotating device which supports a rotating body by a magnetic bearing, which is configured to be controlled to a desired voltage via a DC converter and supplied to the magnetic bearing controlling power supply part.