Magnetic bearing device, turbo molecular pump, and method of controlling magnetic bearing unit

Abstract

To make it possible to operate rotating body in a state where various characteristic values are adjusted even when the various characteristic values are not recorded.SOLUTION: Provided is a magnetic bearing device that includes a rotating body, a magnetic bearing unit that levitates and supports the rotating body in the air using magnetic force, and a control unit which controls the driving of the magnetic bearing unit, wherein the control unit includes a tuning unit that tunes the magnetic bearing unit, a power supply detection unit that detects the state of the power supply of the magnetic bearing device, and a static levitation detection unit that detects whether the rotating body is in a static levitation state, the tuning unit is configured to tune the magnetic bearing unit at least in one of the following cases A and B: (A) when the power supply detection unit detects that the power supply of the magnetic bearing device has been switched from OFF to ON, and (B) when the static levitation detection unit detects that the rotating body is in a static levitation state.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present application relates to a magnetic bearing device, a turbomolecular pump, and a method for controlling a magnetic bearing unit. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2000-240649 (Patent Document 1) is a background art in this technical field. This publication states that "the magnetic bearing main body 20 comprises a resistor 412 for identifying the model, and a main body EEP-ROM 411 in which the model and various characteristic values ​​are stored. The control device 40 comprises a device EEP-ROM 401 in which the model and various characteristics are stored, and a ROM table 402 in which various characteristics corresponding to a plurality of models are stored. The control unit 400 updates the device EEP-ROM 401 with the contents of the main body EEP-ROM 411 when the characteristics of both the main body EEP-ROM 411 and the device EEP-ROM 401 are normal but the two characteristics are not identical" (see abstract). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-240649 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the configuration of Patent Document 1, even if the model of the magnetic bearing body 20 is changed, the various characteristics are automatically adjusted, eliminating the need for adjustment by a specialized engineer. However, it is necessary to record the various characteristics in EEPROM in both the body and the control device. [Means for solving the problem]

[0005] In order to solve the above problems, for example, the configurations described in the claims are adopted. The present application includes a plurality of means for solving the above problems, and examples thereof include: A magnetic bearing device, A rotating body; a magnetic bearing unit that levitates and supports the rotor in the air by magnetic force; a control unit that controls the driving of the magnetic bearing unit; Equipped with The control unit a tuning unit that tunes the magnetic bearing unit; a power supply detection unit that detects the state of a power supply of the magnetic bearing device; a static levitation detection unit that detects whether the rotating body is in a static levitation state; Equipped with The tuning unit (A) when the power supply detection unit detects that the power supply of the magnetic bearing device has been switched from OFF to ON; (B) when the static levitation detection unit detects that the rotating body is in the static levitation state; The magnetic bearing unit is configured to perform tuning on at least one of the above. [Effects of the Invention]

[0006] According to the present invention, even if the various characteristic values ​​are not recorded, the rotating body can be operated in a state in which the various characteristic values ​​have been adjusted. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an example of a vertical cross-sectional view of a turbomolecular pump. [Figure 2] FIG. 2 is an example of a circuit diagram of an amplifier circuit for controlling the rotor shaft of a turbomolecular pump. [Figure 3] FIG. 3 is an example of a time chart showing control when the current command value is larger than the detected value. [Figure 4] FIG. 4 is an example of a time chart showing control when the current command value is smaller than the detected value. [Figure 5]FIG. 5 is an example of a hardware configuration of a control device according to an embodiment. [Figure 6] FIG. 6 is a diagram showing the flow of information in a turbomolecular pump according to one embodiment. [Figure 7] FIG. 7 is a flow chart showing the overall operation of a turbomolecular pump according to one embodiment. [Figure 8] FIG. 8 is a tuning control flow (power ON) according to one embodiment. [Figure 9] FIG. 9 is a tuning control flow (static levitation) according to one embodiment. [Figure 10] FIG. 10 is a flowchart showing a static levitation state determination process according to one embodiment. [Figure 11] FIG. 11 is a tuning control flow (static levitation) according to another embodiment. [Figure 12] FIG. 12 is an example of a vertical cross-sectional view of a turbomolecular pump according to another embodiment. [Figure 13] FIG. 13 is an example of a hardware configuration of a control device according to an embodiment. [Figure 14] FIG. 14 is a block diagram showing an example of a circuit constituting a resolution detection unit of a turbomolecular pump. [Figure 15] FIG. 15 is a tuning control flow (power ON) according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A vacuum pump according to one embodiment will be described below with reference to the drawings. Some of the drawings show X-, Y-, and Z-axes, and each axis is drawn so that it is in a common direction in each drawing. However, these directions are merely for the convenience of explanation and do not limit the installation mode of the vacuum pump in any way. Furthermore, the same components may be assigned a reference number in one drawing and omitted in other drawings.

[0009] [Embodiment 1] <Basic configuration of turbomolecular pump> FIG. 1 shows the basic configuration of a turbomolecular pump 1, which is an example of a vacuum pump. The turbomolecular pump 1 generally comprises a pump main body 100 and a control device 200. The upper part of FIG. 1 is the upstream (intake) side of this turbomolecular pump 1, and an intake port 101 is connected to a vacuum chamber (not shown) of a target device such as a semiconductor manufacturing device. The lower part of FIG. 1 is the downstream (exhaust) side of the turbomolecular pump 1, and an exhaust port 133 is connected to, for example, an auxiliary pump (not shown). This turbomolecular pump 1 can be used in a vertical position as shown in FIG. 1, as well as in an inverted vertical position, a horizontal position, or an inclined position.

[0010] A longitudinal cross-sectional view of this turbomolecular pump 1 is shown in FIG. 1. The flow of information in the turbomolecular pump 1 is shown in FIG. 6. In FIG. 1, a pump main body 100 has an intake port 101 formed at the upper end of a cylindrical outer tube 127. Inside the outer tube 127 is a rotor 103 having a plurality of rotors 102 (102a, 102b, 102c, etc.) which are turbine blades for sucking in and exhausting gas and arranged radially and in multiple stages around its periphery. A rotor shaft 113 is attached to the center of this rotor 103, and this rotor shaft 113 is levitated and supported in the air and its position is controlled by, for example, a five-axis controlled magnetic bearing. The rotor 103 is generally made of metal such as aluminum or an aluminum alloy.

[0011] The upper radial electromagnets 104 are arranged in pairs on the X-axis and the Y-axis. Four upper radial sensors 107 are provided adjacent to the upper radial electromagnets 104 and corresponding to each upper radial electromagnet 104. The upper radial sensors 107 are, for example, inductance sensors or eddy current sensors having conductive windings, and detect the position of the rotor shaft 113 based on changes in the inductance of the conductive windings, which change according to the position of the rotor shaft 113. The upper radial sensors 107 are configured to detect the radial displacement of the rotor shaft 113, i.e., the rotating body 103 fixed thereto, and send the detected displacement to the control device 200.

[0012] In this control device 200, for example, a compensation circuit having a PID adjustment function (see compensation module 218 in Figure 6) generates an excitation control command signal for the upper radial electromagnet 104 based on a position signal detected by the upper radial sensor 107, and an amplifier circuit 150 (described later) shown in Figure 2 controls the excitation of the upper radial electromagnet 104 based on this excitation control command signal, thereby adjusting the upper radial position of the rotor shaft 113.

[0013] The rotor shaft 113 is made of a high magnetic permeability material (iron, stainless steel, etc.) and is attracted by the magnetic force of the upper radial electromagnets 104. Such adjustment is performed independently in the X-axis direction and the Y-axis direction. The lower radial electromagnets 105 and the lower radial sensors 108 are arranged in the same manner as the upper radial electromagnets 104 and the upper radial sensors 107, and adjust the radial position of the lower side of the rotor shaft 113 in the same manner as the radial position of the upper side.

[0014] Furthermore, axial electromagnets 106A and 106B are arranged above and below a circular metal disk 111 provided at the bottom of rotor shaft 113. Metal disk 111 is made of a highly magnetic permeable material such as iron. An axial sensor 109 is provided to detect the axial displacement of rotor shaft 113, and an axial position signal is sent to control device 200.

[0015] In the control device 200, a compensation circuit having, for example, a PID adjustment function generates excitation control command signals for the axial electromagnet 106A and the axial electromagnet 106B based on the axial position signal detected by the axial sensor 109, and the amplifier circuit 150 controls the excitation of the axial electromagnet 106A and the axial electromagnet 106B based on these excitation control command signals, so that the axial electromagnet 106A attracts the metal disc 111 upward by magnetic force, and the axial electromagnet 106B attracts the metal disc 111 downward, thereby adjusting the axial position of the rotor shaft 113.

[0016] In this way, the control device 200 appropriately adjusts the magnetic forces that the axial electromagnets 106A and 106B exert on the metal disk 111, magnetically levitating the rotor shaft 113 in the axial direction and holding it in space without contact. The amplifier circuit 150 that controls the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described later.

[0017] Meanwhile, motor 121 has a plurality of magnetic poles arranged circumferentially so as to surround rotor shaft 113. Each magnetic pole is controlled by control device 200 so as to rotate rotor shaft 113 via electromagnetic force acting between the magnetic pole and rotor shaft 113. Motor 121 also incorporates rotational speed sensor 115 (see FIG. 6), such as a Hall element, resolver, or encoder, and the rotational speed of rotor shaft 113 is detected by the detection signal of rotational speed sensor 115.

[0018] Furthermore, a phase sensor (not shown) is attached, for example, near the lower radial sensor 108, to detect the phase of rotation of the rotor shaft 113. The control device 200 uses the detection signals of this phase sensor and the rotational speed sensor 115 together to detect the position of the magnetic pole.

[0019] A plurality of fixed blades 123 (123a, 123b, 123c...) are arranged at small gaps from the rotating blades 102 (102a, 102b, 102c...). Each of the rotating blades 102 (102a, 102b, 102c...) is formed at an angle of a predetermined degree from a plane perpendicular to the axis of the rotor shaft 113 in order to transport exhaust gas molecules downward through collision. The fixed blades 123 (123a, 123b, 123c...) are made of metal such as aluminum, iron, stainless steel, copper, or an alloy containing any of these metals as an ingredient.

[0020] Similarly, the fixed blades 123 are formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged in a staggered manner with the rows of rotor blades 102 toward the inside of the outer cylinder 127. The outer peripheral ends of the fixed blades 123 are supported by being inserted between a plurality of stacked rows of fixed blade spacers 125 (125a, 125b, 125c, etc.).

[0021] The fixed vane spacer 125 is a ring-shaped member made of a metal such as aluminum, iron, stainless steel, or copper, or an alloy containing any of these metals. An outer cylinder 127 is fixed to the outer periphery of the fixed vane spacer 125 with a small gap between them. A base portion 129 is disposed at the bottom of the outer cylinder 127. An exhaust port 133 is formed in the base portion 129 and communicates with the outside. Exhaust gas that enters the intake port 101 from the chamber (vacuum chamber) side and is transferred to the base portion 129 is sent to the exhaust port 133.

[0022] Furthermore, depending on the application of the turbomolecular pump 1, a threaded spacer 131 is disposed between the lower part of the fixed vane spacer 125 and the base portion 129. The threaded spacer 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, iron, or an alloy containing any of these metals, and has multiple spiral thread grooves 131a engraved on its inner circumferential surface. The spiral direction of the threaded grooves 131a corresponds to the direction in which exhaust gas molecules are transported toward the exhaust port 133 when they move in the rotation direction of the rotor 103. A cylindrical portion 102d hangs down from the lowest part of the rotor 103, adjacent to the rotor vanes 102 (102a, 102b, 102c, etc.). The outer circumferential surface of this cylindrical portion 102d is cylindrical and protrudes toward the inner circumferential surface of the threaded spacer 131, and is adjacent to the inner circumferential surface of the threaded spacer 131 with a predetermined gap therebetween. The exhaust gas transferred to the thread groove 131a by the rotor 102 and the fixed blade 123 is sent to the base portion 129 while being guided by the thread groove 131a.

[0023] Base portion 129 is a disk-shaped member that forms the base of pump body 100, and is generally made of metal such as iron, aluminum, stainless steel, etc. Base portion 129 not only physically holds pump body 100 but also functions as a heat conduction path, so it is desirable to use a metal that is rigid and has high thermal conductivity, such as iron, aluminum, or copper.

[0024] In this configuration, when the rotor 102 is rotated together with the rotor shaft 113 by the motor 121, the action of the rotor 102 and the stator 123 draws exhaust gas from the chamber through the intake port 101. The rotational speed of the rotor 102 is typically 20,000 rpm to 90,000 rpm, and the peripheral speed at the tip of the rotor 102 reaches 200 m / s to 400 m / s. The exhaust gas drawn in through the intake port 101 passes between the rotor 102 and the stator 123 and is transported to the base 129. At this time, the temperature of the rotor 102 rises due to frictional heat generated when the exhaust gas comes into contact with the rotor 102 and conduction of heat generated by the motor 121, but this heat is transferred to the stator 123 side by radiation or conduction through gas molecules of the exhaust gas.

[0025] The stator spacers 125 are joined together at their outer peripheries and transmit to the outside heat received by the stator 123 from the rotor 102 and frictional heat generated when exhaust gas comes into contact with the stator 123.

[0026] In the above description, the threaded spacer 131 is disposed on the outer periphery of the cylindrical portion 102d of the rotor 103, and the thread groove 131a is formed on the inner circumferential surface of the threaded spacer 131. However, there are also cases where the thread groove is formed on the outer circumferential surface of the cylindrical portion 102d, and a spacer having a cylindrical inner circumferential surface is disposed around the outer circumferential surface of the cylindrical portion 102d.

[0027] Depending on the application of the turbomolecular pump 1, the electrical equipment section may be surrounded by a stator column 122 to prevent the gas sucked in from the intake port 101 from entering the electrical equipment section, which is composed of the upper radial electromagnet 104, the upper radial sensor 107, the motor 121, the lower radial electromagnet 105, the lower radial sensor 108, the axial electromagnets 106A and 106B, the axial sensor 109, etc., and the interior of this stator column 122 may be kept at a predetermined pressure by purge gas.

[0028] In this case, piping (not shown) is provided in the base portion 129, and purge gas is introduced through this piping. The introduced purge gas is sent to the exhaust port 133 through gaps between the protective bearing 120 and the rotor shaft 113, between the rotor and stator of the motor 121, and between the stator column 122 and the inner cylindrical portion of the rotor blades 102.

[0029] Here, the turbomolecular pump 1 requires identification of the model and control based on individually adjusted, unique parameters (e.g., various characteristics corresponding to the model). To store these control parameters, the turbomolecular pump 1 generally includes an electronic circuit unit 141 within its main body 100. However, in the turbomolecular pump 1 according to the present technology, the electronic circuit unit 141 does not store the unique control parameters or individual identification information for identifying the individual pump main body 100. The electronic circuit unit 141 typically includes a semiconductor memory such as an EEPROM, electronic components such as semiconductor elements for accessing the memory, a substrate 143 for mounting these components, and the like. The electronic circuit unit 141 is housed below the rotational speed sensor 115, which is provided, for example, near the center of a base 129 constituting the lower part of the pump main body 100, and is closed by an airtight bottom lid 145.

[0030] In the semiconductor manufacturing process, some process gases introduced into a chamber have the property of solidifying when their pressure exceeds a predetermined value or their temperature falls below a predetermined value. Inside the pump body 100, the pressure of the exhaust gas is lowest at the inlet port 101 and highest at the outlet port 133. If the pressure of the process gas exceeds a predetermined value or the temperature falls below a predetermined value while the process gas is being transferred from the inlet port 101 to the outlet port 133, the process gas solidifies and adheres to and accumulates inside the pump body 100.

[0031] For example, when SiCl4 is used as the process gas in an Al etching system, the low vacuum (760 [torr] to 10 -2 The vapor pressure curve shows that at low pressures (approximately 20°C) and pressures of 100 [torr], solid products (e.g., AlCl3) precipitate and adhere to and accumulate inside the pump body 100. If deposits of the process gas accumulate inside the pump body 100, these deposits narrow the pump flow path, causing a decrease in the performance of the turbomolecular pump 1. The aforementioned products tend to solidify and adhere to high-pressure areas near the exhaust port 133 and the threaded spacer 131.

[0032] Therefore, in order to solve this problem, conventionally, a heater (not shown) or a circular water-cooled pipe 149 is wrapped around the outer periphery of the base portion 129, etc., and a temperature sensor (e.g., a thermistor) (not shown) is embedded in the base portion 129, and the heating of the heater and the cooling by the water-cooled pipe 149 are controlled based on the signal from this temperature sensor to maintain the temperature of the base portion 129 at a constant high temperature (set temperature) (hereinafter referred to as TMS; Temperature Management System).

[0033] Next, regarding the turbomolecular pump 1 configured as above, we will explain the amplifier circuit 150 that controls excitation of the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A and 106B. A circuit diagram of this amplifier circuit 150 is shown in FIG.

[0034] 2, one end of the electromagnet winding 151 constituting the upper radial electromagnet 104 etc. is connected to a positive electrode 171a of a power supply 171 via a transistor 161, and the other end is connected to a negative electrode 171b of the power supply 171 via a current detection circuit 181 and a transistor 162. The transistors 161 and 162 are so-called power MOSFETs, and have a structure in which a diode is connected between the source and drain.

[0035] At this time, the transistor 161 has a diode cathode terminal 161a connected to the positive electrode 171a and an anode terminal 161b connected to one end of the electromagnet winding 151. The transistor 162 has a diode cathode terminal 162a connected to the current detection circuit 181 and an anode terminal 162b connected to the negative electrode 171b.

[0036] Meanwhile, current regeneration diode 165 has its cathode terminal 165a connected to one end of electromagnet winding 151 and its anode terminal 165b connected to negative electrode 171b. Similarly, current regeneration diode 166 has its cathode terminal 166a connected to positive electrode 171a and its anode terminal 166b connected to the other end of electromagnet winding 151 via current detection circuit 181. Current detection circuit 181 is configured, for example, with a Hall sensor type current sensor or an electrical resistance element.

[0037] The amplifier circuit 150 configured as above corresponds to one electromagnet. Therefore, if the magnetic bearing is controlled in five axes and there are a total of ten electromagnets 104, 105, 106A, and 106B, a similar amplifier circuit 150 is configured for each electromagnet, and the ten amplifier circuits 150 are connected in parallel to the power supply 171.

[0038] Furthermore, the amplifier control circuit 191 is configured, for example, by a digital signal processor section (hereinafter referred to as a DSP section, DSP: Digital Signal Processor) of the control device 200, and this amplifier control circuit 191 switches the transistors 161 and 162 on / off.

[0039] The amplifier control circuit 191 compares the current value detected by the current detection circuit 181 (a signal reflecting this current value is called a current detection signal 191c) with a predetermined current command value. Based on the comparison result, the amplifier control circuit 191 determines the size of the pulse width (pulse width times Tp1 and Tp2) to be generated within a control cycle Ts, which is one period under PWM control. As a result, gate drive signals 191a and 191b having these pulse widths are output from the amplifier control circuit 191 to the gate terminals of the transistors 161 and 162.

[0040] It is necessary to control the position of rotor 103 at high speed and with strong force when, for example, rotor 103 passes through a resonance point during acceleration of its rotational speed or when a disturbance occurs during constant-speed operation. For this reason, a voltage of, for example, about 50 V is used as power supply 171 so that the current flowing through electromagnet winding 151 can be rapidly increased (or decreased). In addition, a capacitor (not shown) is usually connected between positive electrode 171a and negative electrode 171b of power supply 171 to stabilize power supply 171.

[0041] In this configuration, when both transistors 161 and 162 are turned on, the current flowing through the electromagnet winding 151 (hereinafter referred to as electromagnet current iL) increases, and when both are turned off, the electromagnet current iL decreases.

[0042] Furthermore, when one of the transistors 161 and 162 is turned on and the other is turned off, a so-called flywheel current is maintained. By passing a flywheel current through the amplifier circuit 150 in this manner, hysteresis loss in the amplifier circuit 150 can be reduced, and the power consumption of the entire circuit can be kept low. Furthermore, by controlling the transistors 161 and 162 in this manner, high-frequency noise such as harmonics generated in the turbomolecular pump 1 can be reduced. Furthermore, by measuring this flywheel current with the current detection circuit 181, the electromagnet current iL flowing through the electromagnet winding 151 can be detected.

[0043] That is, when the detected current value is smaller than the current command value, both transistors 161 and 162 are turned on for a time period corresponding to pulse width time Tp1 only once in a control cycle Ts (for example, 100 μs), as shown in Fig. 3. Therefore, during this period, the electromagnet current iL increases toward a current value iLmax (not shown) that can flow from the positive electrode 171a to the negative electrode 171b via the transistors 161 and 162.

[0044] On the other hand, if the detected current value is greater than the current command value, both transistors 161 and 162 are turned off for a time period corresponding to pulse width time Tp2 only once during the control cycle Ts, as shown in Fig. 4. Therefore, the electromagnet current iL during this period decreases toward a current value iLmin (not shown) that can be regenerated from the negative pole 171b to the positive pole 171a via diodes 165 and 166.

[0045] In either case, after the pulse width times Tp1 and Tp2 have elapsed, one of the transistors 161 and 162 is turned on. Therefore, a flywheel current is maintained in the amplifier circuit 150 during this period.

[0046] In the turbomolecular pump 1 described above, for example, the outer cylinder 127 and the base portion 129 are mainly combined to form a single housing. The other elements of the pump main body 100 are housed in this housing. In the following description, the rotor 102, the cylindrical portion 102d, the metal disk 111, and the rotor shaft 113, which are components of the pump main body 100, may be collectively referred to as the rotor 103. The rotor 103 generally includes the metal disk 111 and the rotor shaft 113. In addition, the upper radial electromagnet 104, the lower radial electromagnet 105, the axial electromagnets 106A and 106B, the upper radial sensor 107, the lower radial sensor 108, and the axial sensor 109, which are components of the pump main body 100, may be collectively referred to as the magnetic bearing portion 110. Furthermore, the upper radial sensor 107, the lower radial sensor 108, and the axial sensor 109 may be collectively referred to as displacement sensors 107, 108, and 109. The magnetic bearing unit 110 generally includes electromagnets 104, 105, 106A, and 106B and displacement sensors 107, 108, and 109. The magnetic bearing unit 110 is capable of levitating and / or dynamically stabilizing the rotating body 103 by magnetic attraction or repulsion without mechanical contact.

[0047] FIG. 5 shows an example of a hardware configuration of the control device 200 according to an embodiment. The control device 200 is an element that controls the operation of the turbomolecular pump 1. The control device 200 is mainly composed of, for example, the amplifier circuit 150 as described above and a microcontroller unit (MCU) equipped with the DSP unit described above. The control device 200 is electrically connected to the pump main body 100 via a connection cable 210. For example, the pump main body 100 is equipped with a male connector and the control device 200 is equipped with a female connector, and both ends of the connection cable 210 are equipped with female or male connectors that can be connected to these male or female connectors. The shapes of the connectors are standardized in turbomolecular pumps 1 of the same model.

[0048] The control device 200 may optionally include a processor 203 such as a central processing unit (CPU) that executes digital signal processing and various programs, a main memory device 201 such as a ROM (read only memory) that stores the programs executed by the CPU and a RAM (random access memory) that is used as a working area for expanding the programs, an auxiliary memory device 202 such as a flash memory or an EEP-ROM (Electrically Erasable Programmable Read-Only Memory), an input / output unit 206 that exchanges various information with external devices such as the pump main body 100 or a PC, an input device 204 such as an operation button, and an output device 205 such as a monitor or display.

[0049] The input / output unit 206 may have a communication control function such as a network card, a wireless communication module, a mobile communication module, etc. The control device 200 may further have a clock function (not specifically mentioned) and a temperature sensor such as a thermistor.

[0050] The main memory device 201 stores various programs and applications (software modules), and the processor 203 executes these programs and applications to realize each functional element of the overall system. Each module may be implemented as an independent program or application, or as a subprogram or function within a single integrated program or application. Each module may also be implemented as hardware (hardware module) by employing an integrated circuit or the like.

[0051] In this specification, each module is described as the entity (subject) that performs the processing, but in reality, the processing is performed by the processor 203 executing programs, applications, etc. to realize each module.

[0052] Various databases (DB) are stored in the auxiliary storage device 202. A "database" is, for example, a set of data that has been organized and collected so that it can accommodate any data manipulation (e.g., extraction, addition, deletion, overwriting, etc.) from a processor or an external computer. The auxiliary storage device 202 is a functional element (storage unit) that stores one or more sets of data. The database may be provided in the same housing as the processor 203, etc., in a state connectable to the processor 203, or may be provided independently in a housing different from the processor 203.

[0053] The main memory device 201 stores programs such as a tuning module 211, a pump drive module 212, a current detection module 213, a position detection module 214, a rotation speed detection module 215, a static floating detection module 216, an amplifier control module 217, and a compensation module 218. Each functional element of the control device 200 is realized by the processor 203 executing these programs stored in the main memory device 201.

[0054] The auxiliary storage device 202 stores standard information required for operation of the control device 200. The auxiliary storage device 202 stores, for example, information for determining whether the rotating body 103 is in a static levitation state, such as information relating to reference ranges for the rotation speed of the rotating body 103, the position of the rotating body 103, and the current flowing through the electromagnet winding 151. The auxiliary storage device 202 also stores, for example, operation control information for operating the turbomolecular pump 1, such as information relating to reference ranges for the rotation speed of the rotating body 103 and the current flowing through the electromagnet winding 151. The information relating to the reference ranges is standard target values ​​for the rotation speed of the rotating body 103, the position of the rotating body 103, the current flowing through the electromagnet winding 151, and the like, which are specified for each model of the pump main body 100 when determining the static levitation state and operating the turbomolecular pump.

[0055] These pieces of information may be prepared as a plurality of combinations for each type of model information that identifies the model of the turbomolecular pump 1. In Fig. 5, these pieces of information are represented as turbomolecular pump operation information 221. Note that the model information that identifies the model of the turbomolecular pump 1 corresponds to, for example, the resistance value of an ID resistor 117 (see Fig. 6) that is provided in the pump main body 100 and that differs for each model.

[0056] Each functional element of the control device 200 will now be briefly described. The pump drive module 212 (see FIG. 5) comprehensively controls the basic operation of the turbomolecular pump 1. The pump drive module 212 cooperates with, for example, a current detection module 213, a position detection module 214, a rotation speed detection module 215, a static levitation detection module 216, a compensation module 218, an amplifier control module 217, and the like to control the driving of the turbomolecular pump 1. The pump drive module 212 operates the pump main body 100 by, for example, bringing the rotor 103 into a static levitation state and rotating the rotor 103.

[0057] The tuning module 211 adjusts (i.e., tunes) the transfer function to maintain the rotor 103 in a desired operating state. The tuning module 211 is typically an element that performs tuning related to the position of the rotor 103 of the turbomolecular pump 1. The tuning module 211 cooperates with, for example, the pump drive module 212, the current detection module 213, the position detection module 214, the static float detection module 216, the compensation module 218, the amplifier control module 217, and the like, to adjust the positions of the rotor shaft 113 and the metal disk 111 of the rotor 103 relative to the magnetic bearing unit 110. Note that the tuning module 211 does not perform tuning related to matters other than the position of the rotor 103 of the turbomolecular pump 1.

[0058] The current detection module 213 detects the state of the power supply to the turbomolecular pump 1. In this embodiment, the current detection module 213 detects, for example, the ON state and OFF state of the power supply to the control device 200. The current detection module 213 is also connected to, for example, the current detection circuit 181 of the amplifier circuit 150, and detects the amount of current flowing through the electromagnet windings 151 of the electromagnets 104, 105, 106A, 106B, etc.

[0059] The position detection module 214 detects the position of the rotating body 103. The position detection module 214 is connected to, for example, the displacement sensors 107, 108, and 109, and detects the position of the rotating body 103 relative to the magnetic bearing unit 110. The rotation number detection module 215 detects the rotation number of the rotating body 103. The rotation number detection module 215 is connected to the rotation speed sensor 115, for example, and detects the rotation number of the rotating body 103.

[0060] The static levitation detection module 216 is an element that determines whether the rotating body 103 is in a static levitation state. The static levitation detection module 216 determines whether the rotating body 103 is in a predetermined static levitation state based on, for example, position signals detected by the displacement sensors 107, 108, and 109 and a rotation speed signal detected by the rotation speed sensor 115.

[0061] The amplifier control module 217 is an element in an electric circuit that amplifies various electric signals. The function of the amplifier control module 217 can be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit. The amplifier control circuit 191 having a PWM control function shown in FIG. 2 is an example of a means for realizing the function of the amplifier control module 217 of this embodiment. The amplifier control module 217 can increase, decrease, or maintain the electromagnet current iL by, for example, switching the transistors 161 and 162 of the amplifier circuit 150 between the ON state and the OFF state.

[0062] The compensation module 218 is an element in an electrical circuit that corrects signals. The function of the compensation module 218 can be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit. The compensation circuit described above is an example of a means for realizing the function of the compensation module 218 of this embodiment. The compensation module 218 can operate, for example, to limit within a predetermined range the deviation of the rotating body 103 based on the position signal of the rotating body 103 detected by the displacement sensors 107, 108, and 109. Furthermore, the compensation module 218 can operate, for example, to limit within a predetermined range the deviation of various sensor signals due to the environmental temperature detected by a temperature sensor (not shown).

[0063] <Operation of turbomolecular pump> First, an overview of the operation method of the turbomolecular pump 1 will be explained, followed by an explanation of tuning control by the control device 200. Fig. 7 is a flowchart showing the overall operation of the turbomolecular pump 1 according to one embodiment. The pump drive module 212 of the control device 200 cooperates with other modules as necessary and executes the following processes.

[0064] The control device 200 is turned on when, for example, a user or an external device turns on the power (step S710). Then, when the pump drive module 212 receives an instruction signal to start operation (Yes in step S715), it starts magnetic levitation of the rotor 103 by the magnetic bearing unit 110 (step S720). The pump drive module 212 may be configured to turn off (step S770), for example, when it does not receive an instruction signal to start operation within a predetermined period (No in step S715), when it receives an instruction signal to turn off the power, or when it receives an error signal. Alternatively, the pump drive module 212 may omit step S715 and start magnetic levitation (step S720) immediately when it turns on (step S710). The instruction signal to start operation, for example, may be input from a user or an external device, or may be generated by the processor 203 executing an operating program for the turbomolecular pump 1. The same applies to instruction signals whose senders are not specified below.

[0065] When magnetic levitation starts, the tuning module 211 executes a tuning process (step S730), which will be described later.

[0066] After the tuning step, for example, when the pump drive module 212 receives a command signal to start rotation of the rotor 103 (Yes in step S735), the pump drive module 212 rotates the rotor 103 to start suction (step S740). The pump drive module 212 drives the rotor shaft 113 to rotate by electrically controlling the operating state of the motor 121. Then, for example, the pump drive module 212 continues rotating the rotor 103 until it receives a command signal to stop rotation of the rotor 103 (No in step S745), and when it receives a command signal to stop rotation (Yes in step S745), it stops the rotation of the rotor 103 and ends suction (step S750). Note that the pump drive module 212 may be configured to end magnetic levitation (step S760), for example, when it does not receive a command signal to start rotation within a predetermined period (No in step S735), when it receives a command signal to stop magnetic levitation, or when it receives some kind of error signal. In addition, the pump drive module 212 may be configured to terminate rotation (step S750) in step S745, for example, when a predetermined rotation operation time has elapsed or when some error signal is obtained.

[0067] If a command signal to re-rotate is received after rotation has ended (Yes in step S755), the process returns to step S730, and tuning module 211 executes tuning control flow (static levitation) 900. On the other hand, if a command signal to re-rotate is not received (No in step S755), pump drive module 212 ends the magnetic levitation of rotor 103 (step S760). Note that pump drive module 212 may be configured to end magnetic levitation (step S760), for example, if a command signal to re-rotate is not received within a predetermined period, if a command signal to end magnetic levitation is received, or if some kind of error signal is received.

[0068] If a restart command signal is received after magnetic levitation is completed (Yes in step S765), the pump drive module 212 returns to step S720. If a restart command signal is not received (No in step S765), the pump drive module 212 turns the power OFF (step S770). The pump drive module 212 may be configured to turn the power OFF, for example, if it does not receive a restart command signal within a predetermined period, if it receives a command signal to turn the power OFF, or if it receives some kind of error signal.

[0069] In the turbomolecular pump 1, the levitation control parameters for magnetic levitation generally vary depending on the combination of the pump main body 100 model and the control device 200 model. Specifically, for example, the levitation control parameters may differ for each combination of the pump main body 100 and the control device 200 due to variations in component dimensions, assembly accuracy, and the like, even within design tolerances. For this reason, the electronic circuit section of the conventional pump main body 100 stores, for example, model information for identifying the model (type) of the pump main body 100, individual identification information (e.g., a serial number) for identifying an individual pump main body 100, and information regarding the levitation control parameters specific to the combination with the control device 200.

[0070] The levitation control parameter information is information used by the control device 200 to operate the pump main body 100, and is, for example, control parameters (specifically, the control gain and sensor offset of the magnetic bearing unit 110, for example) used when controlling the drive of the magnetic bearing unit 110 for the purpose of magnetically levitating or rotating the rotating body 103. This levitation control parameter information is typically adjusted for each combination of a specific pump main body 100 and control device 200 during initial setup of the turbomolecular pump 1, and is stored in the electronic circuit unit 141.

[0071] On the other hand, a user who owns a plurality of turbo molecular pumps 1 may, for example, when a certain pump body 100 or control device 200 malfunctions, consider reconnecting and operating the pump body 100 with a control device 200 in a different combination. In such a case, the levitation control parameter information stored in the pump body 100 is optimized for the combination with the original control device 200, and may not be suitable for the combination with the control device 200 after recombination. If the turbo molecular pump 1 is operated using non-optimal levitation control parameters, the rotor 103 may vibrate during operation, or the magnetic bearing portion 110 may contact the protection bearing 120, etc., and the turbo molecular pump 1 may be damaged.

[0072] <Tuning> The electronic circuit portion 141 of the pump body 100 of the present embodiment does not store individual identification information for identifying the individual of the pump body 100 and information regarding levitation control parameters. And the tuning module 211 of the present embodiment executes, for example, the following tuning process in order to cope with the case where the combination of the pump body 100 and the control device 200 is changed.

[0073] That is, the tuning module 211 executes tuning of the magnetic bearing portion 110 when at least one of (A) the current detection module 213 detects that the power supply of the turbo molecular pump 1 has been switched from OFF to ON and (B) the stationary levitation detection module 216 detects that the rotor 103 is in a stationary levitation state.

[0074] Specific examples of the tuning methods (A) and (B) of the magnetic bearing portion 110 by the tuning module 211 are shown below, and the operation of the tuning module 211 will be described. The tuning module 211 executes tuning of the magnetic bearing portion 110 corresponding to the operation of the pump drive module 212 shown in FIG. 7, for example (step S730).

[0075] <A. Tuning Based on Power-On> 8 is a tuning control flow (power ON) 800 according to one embodiment. At the start of tuning control flow 800, the tuning request flag is OFF. 7 is turned ON (step S710). That is, when the current detection module 213 detects that the power supply of the turbo molecular pump 1 has been switched from OFF to ON (Yes in step S810), the tuning module 211 changes the tuning request flag to ON (step S820). When the current detection module 213 does not detect that the power supply has been switched from OFF to ON (No in step S810), the tuning module 211 does not turn the tuning request flag ON, but leaves it OFF.

[0076] FIG. 9 is a tuning control flow (static levitation) 900 according to one embodiment. The tuning module 211 repeatedly executes the tuning control flow 900. That is, the tuning module 211 evaluates whether the rotating body 103 is in a statically levitated state (step S910). The tuning module 211 evaluates whether the rotating body 103 is in a statically levitated state, for example, based on the determination by the static levitation detection module 216, which will be described later.

[0077] If the rotating body 103 is in a static levitation state (Yes in step S910), the tuning module 211 determines whether the tuning request flag is ON (step S920). If the tuning request flag is ON (Yes in step S920), the tuning module 211 performs tuning of the magnetic bearing unit 110, which will be described later (step S930). When tuning of the magnetic bearing unit 110 is completed, the tuning module 211 changes the tuning request flag to OFF (step S940) and ends the tuning control flow 900.

[0078] On the other hand, if the rotating body 103 is not in a static levitation state (No in step S910), the tuning module 211 repeatedly executes step S910. Furthermore, if the tuning request flag is not ON (No in step S920), the tuning module 211 ends the tuning control flow 900. Note that the tuning module 211 may be configured to repeatedly execute the tuning control flow 900 at all times, or may be configured to repeatedly execute the tuning control flow 900 when a predetermined execution condition is met (for example, when the motor 121 is not driven).

[0079] FIG. 10 is a flowchart showing a static levitation state determination process according to one embodiment. The static levitation detection module 216 executes the following process to determine whether the rotating body 103 is in a static levitation state. That is, the static levitation detection module 216 determines whether any error (e.g., an emergency stop signal input from an external source) has been detected in the turbomolecular pump 1 (step S1010). If no error has been detected (Yes in step S1010), the static levitation detection module 216 determines whether the rotation speed detected by the rotation speed detection module 215 is within a reference range (step S1020). The reference range for the rotation speed can be, for example, approximately 1 Hz or less, at which the rotating body 103 can be considered to be stationary.

[0080] If the rotation speed is within the reference range (Yes in step S1020), the static levitation detection module 216 determines whether the position of the rotating body 103 relative to the magnetic bearing unit 110, detected by the position detection module 214, is within the reference range (step S1030). The reference range for the position of the rotating body 103 may be, for example, ±5 μm from the reference position (target levitation position) of the rotating body 103 of the corresponding model of the pump main body 100. If the position of the rotating body 103 is within the reference range (Yes in step S1030), the static levitation detection module 216 determines whether the current flowing through the electromagnet winding 151, detected by the current detection module 213, is within the reference range (step S1040). The reference range for the current of the electromagnet winding 151 may be, for example, a range of 0.2 A to 1.0 A.

[0081] If the current is within the reference range (Yes in step S1040), the static floating detection module 216 determines that the rotating body 103 is in a static floating state (step S1050). If the results in steps S1010 to S1040 are No, the static floating detection module 216 determines that the rotating body 103 is not in a static floating state (step S1060). Note that the static floating detection module 216 can execute steps S1010 to S1040 in any order.

[0082] The tuning of the magnetic bearing unit 110 performed by the tuning module 211 will now be described. Tuning module 211 adjusts (corrects) the magnetic bearing control gain and the offsets of displacement sensors 107, 108, and 109 as levitation control parameters. Tuning module 211 adjusts the control parameters by, for example, checking characteristics through step response or vibration tests. More preferably, tuning module 211 adjusts only the offsets of displacement sensors 107, 108, and 109 as levitation control parameters. Adjusting only the offsets of displacement sensors 107, 108, and 109 is preferable because it shortens the time required for tuning and allows critical adjustments to be made.

[0083] <Displacement sensor offset> The tuning module 211 vibrates the rotating body 103 in each of the upper radial direction, the lower radial direction, and the axial direction. The tuning module 211 displaces the rotating body 103 in one and the other directions so that it hits the protective bearing 120. Based on the detection result of the vibration response (displacement signal) at this time, the tuning module 211 sets, for example, the center of the displacement position when the rotating body 103 hits the protective bearing 120 on one and the other sides as the offset (zero point) of the displacement sensors 107, 108, and 109. By adjusting the position of the rotating body 103 to this offset (zero point) of the displacement sensors 107, 108, and 109, it is possible to align, for example, the rotation reference position of the rotating body 103 (the center of rotation of the rotor shaft 113) and the center of the clearance of the protective bearing 120. The tuning module 211 may detect the levitation position where the difference in integral outputs, which is the difference in control currents flowing through opposing electromagnets, becomes zero as the magnetic center, and use this as the offset of the displacement sensors 107, 108, and 109. The tuning module 211 stores the obtained offsets of the displacement sensors 107, 108, and 109 in, for example, the auxiliary storage device 202 as turbomolecular pump operation information.

[0084] <Magnetic bearing control gain settings> The magnetic axis controlled gain can be set using, for example, the step response or the limit sensitivity method. The tuning module 211 evaluates, for example, the response characteristics when the magnetic axis controlled gain is applied while gradually increasing it stepwise from a small value to a large value, and sets the control gain based on the gain at that time when the oscillation of the response signal satisfies a predetermined end condition. The tuning module 211 sets, for example, a gain that is a predetermined amount smaller than the gain at the end condition as the control gain. Alternatively, the tuning module 211 gradually increases the magnetic axis controlled gain, obtains, for example, the limit gain and the limit period that satisfy a predetermined continuous oscillation condition, and can adjust the control device 200 based on the gain at which the amplitude decays to 1 / 4 and the response period at that time. The tuning module 211 stores the obtained magnetic axis controlled gain, for example, in the auxiliary storage device 202 as turbo molecular pump operation information.

[0085] <B. Tuning Based on Static Levitation> FIG. 11 shows a tuning control flow (static levitation) 1100 according to an embodiment. When performing tuning based on static levitation, the tuning module 211 repeatedly executes the tuning control flow 1100. The tuning control flow 1100 is common to the tuning control flow 900 except that the step S1150 described later is different. In the start state of the tuning control flow 1100, the tuning request flag is OFF.

[0086] That is, the tuning module 211 evaluates whether the rotating body 103 is in a static levitation state (step S1110). The tuning module 211 evaluates whether the rotating body 103 is in a static levitation state based on, for example, the determination by the above-described static levitation detection module 216.

[0087] If the rotating body 103 is in a static levitation state (Yes in step S1110), the tuning module 211 determines whether the tuning request flag is ON (step S1120). If the tuning request flag is ON (Yes in step S1120), the tuning module 211 performs the above-described tuning of the magnetic bearing unit 110 (step S1130). When tuning of the magnetic bearing unit 110 is completed, the tuning module 211 changes the tuning request flag to OFF (step S1140) and ends the tuning control flow 1100.

[0088] On the other hand, if the rotating body 103 is not in a static levitation state in step S1110 (No in step S1110), the tuning module 211 changes the tuning request flag to ON (step S1150) and returns to step S1110. Also, if the tuning request flag is not ON in step S1120 (No in step S1120), the tuning module 211 ends the tuning control flow 1100. Note that the tuning module 211 may be configured to repeatedly execute the tuning control flow 1100 at all times, or may be configured to repeatedly execute the tuning control flow 1100 when a predetermined execution condition is met (for example, when the motor 121 is not driven).

[0089] <Action and effect> In the above configuration, the turbomolecular pump 1 (an example of a magnetic bearing device) includes a rotor 103, a magnetic bearing unit 110 that levitates and supports the rotor 103 in the air using magnetic force, and a control device 200 (an example of a control unit) that controls the driving of the magnetic bearing unit 110. The control device 200 includes a tuning module 211 (an example of a tuning unit) that tunes the magnetic bearing unit 110, a current detection module 213 (an example of a power supply detection unit) that detects the state of the power supply of the turbomolecular pump 1, and a static levitation detection module 216 (an example of a static levitation detection unit) that detects whether the rotor 103 is in a static levitation state. The tuning module 211 is configured to tune the magnetic bearing unit 110 at least in one of the following cases: (A) when the current detection module 213 detects that the power supply of the turbomolecular pump 1 has been switched from OFF to ON, or (B) when the static levitation detection module 216 detects that the rotor 103 is in a static levitation state.

[0090] This allows tuning to be performed at least each time the power is switched from an OFF state to an ON state. As a result, even if the pump main body 100 is changed while the power is OFF, tuning is always performed, making it possible to operate the turbomolecular pump 1 with the levitation control parameters optimized. Furthermore, the magnetic bearing unit 110 can levitate and support the rotor 103 at an appropriate position in both the radial and axial directions, allowing the turbomolecular pump 1 to operate stably and avoiding damage, etc.

[0091] Furthermore, by having the tuning module 211 perform tuning each time the static levitation detection module 216 detects a static levitation state, tuning is performed each time the intake of air by the turbomolecular pump 1 stops. This makes it possible to operate the turbomolecular pump 1 by maintaining the levitation control parameters in an optimal state each time, even when the operation of the turbomolecular pump 1 continues for a long period of time, such as when the rotating body 103 is rotated again after rotation has finished, or when the static levitation state is resumed after the static levitation state has ended.

[0092] The timing at which the tuning module 211 performs tuning may be either (A) or (B) above. Also, as shown in the above configuration, the tuning module 211 may be configured to tune the magnetic bearing unit 110 when (A) the current detection module 213 detects that the power supply of the turbomolecular pump 1 has been switched from OFF to ON, and (B) the static levitation detection module 216 detects that the rotating body 103 is in a static levitation state. This makes it possible to operate the turbomolecular pump 1 with the levitation control parameters optimized in preparation for a case in which the pump main body 100 is changed.

[0093] In the above configuration, the turbomolecular pump 1 includes, for example, a pump body 100 (an example of a pump unit) that includes a rotor 103 and a magnetic bearing unit 110 and has rotor blades 102 for discharging gas on at least a part of the rotor 103, and a control device 200 (an example of a control unit that includes a control unit). In other words, the turbomolecular pump 1 can be understood as an example of a magnetic bearing device according to the present technology.

[0094] Furthermore, in the above configuration, tuning module 211 is configured to tune magnetic bearing unit 110 when rotation speed detection module 215 (an example of a rotation detection unit) detects that rotating body 103 has changed from a rotating state to a non-rotating state, and when static levitation detection module 216 detects that rotating body 103 is in a static levitation state. This makes it possible to reliably confirm that rotating body 103 is in a static levitation state, and to perform tuning safely and accurately without being affected by vibrations or the like due to rotation.

[0095] Furthermore, in the above configuration, the tuning module 211 is configured to adjust the rotational reference position of the rotor 103 based on information relating to the position of the rotor 103 relative to protective bearings 120 (an example of a peripheral component) arranged around the rotor 103, as tuning. This makes it possible to adjust the levitation control parameters to correspond to individual variations in the pump body 100 through simple processing in a relatively short time, even when the pump body 100 is changed. As a result, it is possible to stably achieve a static levitation state for the turbomolecular pump 1, and to suitably suppress vibration characteristics within the operating frequency range.

[0096] In the above configuration, tuning module 211 is configured to be able to perform tuning without acquiring levitation control parameters from pump main body 100. This allows pump main body 100 to be realized as not having electronic circuit section 141 (an example of a storage section) in which levitation control parameters (an example of control information) for operating pump main body 100 are stored.

[0097] Furthermore, in the above configuration, the tuning module 211 is configured to be able to perform tuning without obtaining individual identification information that identifies the individual pump body 100 from the pump body 100. This allows the pump body 100 to be realized as not having a memory unit that stores individual identification information that identifies the individual pump body 100. By extension, it will be understood by those skilled in the art that the pump body 100 can be realized as not having the electronic circuit unit 141 itself, such as an EEPROM. In this way, the pump body 100 can be configured as not having a memory unit in the electronic circuit unit 141, or as not having the electronic circuit unit 141. By adopting such a configuration, it is possible to reduce the cost of the turbomolecular pump 1 (pump body 100).

[0098] The tuning module 211 is configured to set the magnetic levitation control parameters without being influenced by the levitation control parameters, even if they are stored in the electronic circuit unit 141 of the pump main body 100. For example, even if the levitation control parameters are pre-stored in the electronic circuit unit 141 of the pump main body 100, the tuning module 211 may be configured to set the magnetic levitation control parameters without reading the pre-stored levitation control parameters. Alternatively, even if the levitation control parameters are pre-stored in the electronic circuit unit 141 of the pump main body 100 and the tuning module 211 reads the pre-stored levitation control parameters, the tuning module 211 may be configured to set new magnetic levitation control parameters based on the above configuration without being influenced by the pre-stored levitation control parameters. Thus, the control device 200 configured as described above can operate the turbomolecular pump 1 with the levitation control parameters optimized by appropriately tuning the electronic circuit unit 141, regardless of whether or not it is present and the information stored therein.

[0099] [Embodiment 2] <Configuration of turbomolecular pump> A turbomolecular pump 1A according to the second embodiment will be described with reference to Figs. 12 to 15. Fig. 12 is an example of a vertical cross-sectional view of the turbomolecular pump 1A according to the second embodiment. Fig. 13 is an example of a hardware configuration of a control device 200 according to the second embodiment. Fig. 14 is a block diagram showing an example of a circuit constituting a resolution detection unit of the turbomolecular pump. Fig. 15 is a tuning control flow (power ON) according to the second embodiment.

[0100] The turbomolecular pump 1A of embodiment 2 differs from embodiment 1 in that the pump main body 100 and the control device 200 are integrally connected by a mechanical connection part 231 and an electrical connection part 232, and that a disassembly detection part 235 is further provided near the connection part between the control device 200 and the mechanical connection part 231, and a connection detection module 219 is further provided in the main memory device 201 of the control device 200. The rest of the configuration may be the same as embodiment 1, and a description of the same configuration, action, and effect will be omitted.

[0101] 12, the housing of pump body 100 and the housing of control device 200 are mechanically fixed together by mechanical connection part 231. Electronic circuit part 141 of pump body 100 and amplifier circuit 150 of control device 200 are electrically connected by electrical wiring 210A (not shown) that extends through electrical connection part 232. Electrical wiring 210A has connectors on both ends, for example, so that the connector on one end is connected to a socket provided in electronic circuit part 141 of pump body 100 and the connector on the other end is connected to a socket provided in amplifier circuit 150 of control device 200.

[0102] As shown in FIG. 14 , the disassembly detection unit 235 includes a disassembly detection switch 235S, a disassembly information storage unit 235M, and a power supply unit 235V for maintaining the voltage of the disassembly information storage unit 235M. The disassembly detection switch 235S is installed and operates so that the circuit is opened when the control device 200 and the pump body 100 are separately detached (disconnected), and the circuit is closed when the control device 200 and the pump body 100 are integrally assembled. The disassembly detection switch 235S may be configured, for example, by an automatic reset contact such as a push button switch. The disassembly information storage unit 235M stores information indicating that the control device 200 and the pump body 100 have not been detached (disassembled). The disassembly information storage unit 235M may be configured, for example, by a storage device such as an SRAM (Static Random Access Memory). In the disassembly detection unit 235 configured as described above, when the contacts of the disassembly detection switch 235S open, the voltage of the disassembly information storage unit 235M is not maintained, and the information stored in the disassembly information storage unit 235M indicating that the product has not been disassembled is erased.

[0103] The connection detection module 219 is configured to detect whether the connection between the pump main body 100, which includes the rotating body 103 and the magnetic bearing unit 110, and the control device 200 has been released. The connection detection module 219 is electrically connected, for example, to the disassembly information storage unit 235M of the disassembly detection unit 235. The connection detection module 219 determines that the connection between the pump main body 100 and the control device 200 has not been released if the disassembly information storage unit 235M stores information indicating that the pump main body 100 has not been disassembled. The connection detection module 219 also determines that the connection between the pump main body 100 and the control device 200 has been released if the disassembly information storage unit 235M does not store information indicating that the pump main body 100 has not been disassembled.

[0104] <Operation of turbomolecular pump> In such a turbomolecular pump 1A, when the power supply of Fig. 7 is turned ON (step S710), the tuning module 211 executes the tuning control flow 1500 shown in Fig. 15. That is, when the current detection module 213 detects that the power supply of the turbomolecular pump 1 has switched from OFF to ON (Yes in step S1510), the tuning module 211 evaluates whether the connection detection module 219 has detected that the pump main body 100 and the control device 200 have been disconnected (step S1520).

[0105] If the connection detection module 219 detects a disconnection (Yes in step S1520), the tuning module 211 changes the tuning request flag to ON (step S1520). If the connection detection module 219 does not detect a disconnection (No in step S1520), the tuning module 211 does not change the tuning request flag to ON, but leaves it OFF. Thereafter, the tuning module 211 operates in the same manner as in the first embodiment. That is, when the pump drive module 212 starts magnetic levitation (step S720), the tuning module 211 executes the tuning control flow 900. After executing the tuning control flow 900, the tuning module 211 stores information indicating that the pump drive module 212 has not been disassembled in the disassembly information storage unit 235M.

[0106] <Action and effect> In the above configuration, the control device 200 (an example of a control unit) includes a connection detection module 219 (an example of a connection detection unit) configured to detect whether the connection between the magnetic bearing unit 110 and the control device 200 has been released. The tuning module 211 is configured to perform tuning when the current detection module 213 detects that the power supply has been turned on and the connection detection module 219 (an example of a connection detection unit) detects that the connection between the magnetic bearing unit 110 and the control device 200 (an example of a control unit) has been released. This makes it possible to operate the turbomolecular pump 1 with the levitation control parameters optimized whenever the pump main body 100 is changed for the control device 200, for example.

[0107] In addition, from another perspective, a person skilled in the art will understand that the control device 200 may only have a configuration in which the tuning module 211 performs tuning when the (C) connection detection module 219 detects that the connection between the pump main body 100 and the control device 200 has been disconnected.

[0108] <Modification> In the above configuration, disassembly detection unit 235 is provided near mechanical connection unit 231 and is configured to detect disassembly between pump main body 100 and control device 200. However, the form of disassembly detection unit 235 is not limited to this. For example, disassembly detection unit 235 may be provided in relation to electrical wiring 210A. Disassembly detection switch 235S may be provided in a control device-side connector of electrical wiring 210A that electrically connects the DSP unit of control device 200 and electromagnets 104, 105, 106A, and 106B (electromagnet winding 151) of pump main body 100. Disassembly detection switch 235S is, for example, an automatic reset contact such as a push switch provided in a connector portion (e.g., a plug) on ​​the control device side, and is configured to be pressed and close the contact when inserted into a connector portion (socket) on the pump main body 100 and reaches a predetermined connection position. Furthermore, disassembly detection switch 235S is configured so that the contacts open when the connector portion (plug) on ​​the control device 200 side is separated from the connector portion (socket) on the pump main body 100 side. With this configuration, disassembly of the pump main body 100 and the control device 200 can be detected, as in the second embodiment.

[0109] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to combine the configuration of one embodiment with the configuration of another embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration. The above-described embodiment discloses at least the configurations described in the claims. [Explanation of symbols]

[0110] 1... turbomolecular pump, 100... pump body, 103... rotating body, 104... upper radial electromagnet, 105... lower radial electromagnet, 106A, 106B... axial electromagnet, 107... upper radial sensor, 108... lower radial sensor, 109... axial sensor, 115... rotational speed sensor, 211... tuning module, 212... pump drive module, 213... current detection module, 214... position detection module, 215... rotation speed detection module, 216... static levitation detection module, 217... amplifier control module, 218... compensation module

Claims

1. A magnetic bearing device, A rotating body; a magnetic bearing unit that levitates and supports the rotor in the air by magnetic force; a control unit that controls the driving of the magnetic bearing unit; Equipped with The control unit a tuning unit that tunes the magnetic bearing unit; a power supply detection unit that detects the state of a power supply of the magnetic bearing device; a static levitation detection unit that detects whether the rotating body is in a static levitation state; Equipped with The tuning unit (A) when the power supply detection unit detects that the power supply of the magnetic bearing device has been switched from OFF to ON; (B) the static levitation detection unit detects that the rotating body is in the static levitation state; and performing tuning of the magnetic bearing unit on at least one of the above. Magnetic bearing device.

2. the control unit includes a rotation detection unit that detects whether the rotating body is rotating, the tuning unit is configured to tune the magnetic bearing unit when the rotation detection unit detects that the rotating body has changed from a rotating state to a non-rotating state and when the static levitation detection unit detects that the rotating body is in the static levitation state.

2. A magnetic bearing device according to claim 1.

3. The tuning unit is configured to tune the magnetic bearing unit when (A) the power supply detection unit detects that the power supply of the magnetic bearing device has been switched from OFF to ON, and (B) the static levitation detection unit detects that the rotating body is in the static levitation state.

2. A magnetic bearing device according to claim 1.

4. the control unit includes a connection detection unit configured to detect whether the connection between the magnetic bearing unit and the control unit has been released, The tuning unit is configured to tune the magnetic bearing unit when (C) the power supply detection unit detects that the power supply of the magnetic bearing device is ON and (D) the connection detection unit detects that the connection between the magnetic bearing unit and the control unit has been released.

2. A magnetic bearing device according to claim 1.

5. the tuning unit is configured to adjust a rotational reference position of the rotating body based on information related to a position of the rotating body relative to peripheral components arranged around the rotating body.

2. A magnetic bearing device according to claim 1.

6. the rotating body and the magnetic bearing unit, a pump unit having a rotor for discharging gas on at least a part of the rotor; a control unit including the control unit; Equipped with The turbomolecular pump according to any one of claims 1 to 5.

7. a wiring section for connecting the pump unit and the control unit; the pump unit includes a pump-side connection portion to which one end of the wiring portion is connected, and the control unit includes a control-side connection portion to which the other end of the wiring portion is connected.

7. The turbomolecular pump according to claim 6.

8. The pump unit does not include a memory unit in which control information for operating the pump unit is stored.

7. The turbomolecular pump according to claim 6.

9. The pump unit does not include a memory unit that stores individual identification information that identifies the individual pump unit.

9. The turbomolecular pump according to claim 8.

10. A method for controlling a magnetic bearing unit that levitates and supports a rotating body in the air using magnetic force, comprising: a control unit for controlling the driving of the magnetic bearing unit; (A) When it is detected that the power supply of the magnetic bearing device including the rotating body, the magnetic bearing unit, and the control unit has been switched from OFF to ON, (B) when it is detected that the rotating body is in a static levitation state; and performing tuning of the magnetic bearing unit on at least one of the above. A method for controlling a magnetic bearing unit.

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