Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
  • F16C32/0406—Magnetic bearings
  • F16C32/044—Active magnetic bearings
  • F16C32/0444—Details of devices to control the actuation of the electromagnets
  • F16C32/0451—Details of controllers, i.e. the units determining the power to be supplied, e.g. comparing elements, feedback arrangements with P.I.D. control

Definitions

• the present invention relates to a control device for a magnetic bearing of a device using a magnetic bearing as a means for supporting the rotating body, and more particularly to a control suitable for suppressing the vibration amplitude of the unbalanced rotating body against whirling motion.
• the present invention relates to a magnetic bearing device.
• Fig. 1 shows the basic configuration of a conventional general control type magnetic bearing device equipped with a feedback control system.
• a part of the bearing device that supports the radial direction of the rotating shaft 1 is extracted, and the rotating body along the X-axis direction of the X-Y axis plane (cross section) orthogonal to the rotating shaft 1 is taken out.
• An example in which the vibration amplitude of 1 is controlled will be described. That is, in the figure, the X axis is taken on the horizontal axis and the Y axis is taken on the vertical axis around the axis of the rotating body 1, and the displacement sensors 2a and 2b are sandwiched on the X axis so as to sandwich the rotating body 1.
• the electromagnets 3a and 3b are arranged to control the current supplied to the electromagnets 3a and 3b based on the sensor signals of the displacement sensors 2a and 2b.
• An electromagnet and a displacement sensor are similarly arranged at positions sandwiching the, and are similarly controlled.
• displacement sensors 2a and 2b which are arranged at positions sandwiching the rotation axis 1 on the X axis and detect the displacement of the rotation axis 1 in the radial direction, are connected to the sensor amplifier 4.
• the displacement sensors 2a and 2b and the sensor amplifier 4 constitute a displacement sensor unit.
• the output signal of the sensor amplifier 4 is an electric signal (sensor signal) corresponding to the displacement of the rotating body 1 along the X-axis direction. This sensor signal is used to hold the rotating body 1 at a desired floating position. It is input to a first control unit 5 which forms a compensation signal.
• the first control unit 5 calculates the first control signal based on the sensor signal and outputs it as a control current.
• This control signal (control current) is individually connected to each of the electromagnets 3a and 3b.
• the power is amplified by the power amplifiers 6a and 6b and supplied to the coils of the electromagnets 3a and 3b, respectively.
• an electromagnetic force is generated by the current supplied to each of the coils, and the rotating body 1 is magnetically attracted to the electromagnets 3a and 3b by the electromagnetic force.
• a control current is supplied to the pair of electromagnets 3a and 3b arranged on the X-axis, and the rotating body 1 Servo control is performed so that 1 floats at the center position or target position.
• the rotating body when a rotating body with a large amount of unbalance is supported and rotated in the radial direction by a magnetic bearing, the rotating body may rotate eccentrically, that is, so-called whirling may occur.
• the amount of eccentricity of the rotating body becomes large, the whirling range of the rotating body does not fit in the gap of the magnetic bearing, and as a result, non-contact floating support of the rotating body cannot be performed, resulting in damage to the equipment. There is a risk of connection.
• the rotator swings largely as described above, and depending on the degree, it may lead to a downfall.
• the problem can be solved by applying a bearing that can generate sufficient control force against external force.
• the rigidity of the magnetic bearing is smaller than that of the rolling bearing / sliding bearing, it is difficult to make the magnetic bearing have the same rigidity as the rolling bearing / sliding bearing.
• the magnetic flux density is generally about 0.5 Tesla, so that only about 10 Newtons can be obtained.
• the present invention has been made in view of the above circumstances, and generates a control signal based on a sensor signal from a displacement sensor that detects a radial displacement of a rotating body.
• An object of the present invention is to provide a control-type magnetic bearing device that generates and suppresses whirling of a rotating body due to an external force synchronized with a rotating motion so that the rotating body can be stably levitated and supported.
• the voltage signal proportional to the rotation speed obtained from the existing motor controller is used for turning on / off the signal switch before inputting the control signal to the power amplifier, or the operation of the rotation speed component extraction filter. Used for
• the invention according to claim 1 includes a displacement sensor that detects a radial displacement of a rotating body, and a first control unit that calculates and outputs a first control signal based on a sensor signal from the displacement sensor.
• a control type magnetic bearing device that radially supports a rotating body including a power amplifier that drives a current based on the first control signal, and an electromagnet that generates a magnetic force by a signal from the power amplifier;
• a second control unit arranged in parallel with the first control unit, for introducing the sensor signal and generating and outputting a second control signal having a phase changed from the sensor signal; and
• a signal combiner that generates a control signal by adding a second control signal output from the control unit of the first control unit to the first control signal output from the first control unit and outputs the control signal to the power amplifier.
• the amount of phase change in the second control unit is preferably set to a value suitable for suppressing the whirling of the rotating body from the transmission characteristics of the external force / displacement of the magnetic bearing.
• the set value of the phase adjuster in the second control unit is referred to. Is determined, and the obtained second control unit output signal is added to the first control unit output signal, and input to the power amplifier unit to control the current of the electromagnet, so that the rotating body The whirling can be reduced.
• the second control unit includes: a filter that extracts a rotation frequency component from the sensor signal; and a phase adjuster that adjusts a phase of an output signal of the filter.
• a signal adjuster including a comparator for comparing the output signal of the phase adjuster with a reference potential; and a gain adjuster for adjusting the amplitude of the output signal of the signal adjuster.
• the second control unit is configured to provide a variable frequency filter and a phase change amount suitable for suppressing whirling of the rotating body corresponding to the motor rotation speed.
• a sensor signal corresponding to the motor rotation speed due to the variable frequency filter is taken out, and a phase change amount suitable for suppressing the whirling of the rotating body is given to the taken out signal to thereby provide a phase change amount.
• an appropriate amount of phase can be adjusted for an arbitrary rotation speed. Therefore, the whirling of the rotating body in a wide rotation speed range Can be reduced.
• the means for providing a phase change amount suitable for suppressing the whirling of the rotating body corresponding to the motor rotation speed measures the transfer characteristic data of the external force / displacement of the magnetic bearing and stores the measured value in accordance with the rotation speed. It is preferable to have a memory and a phase adjuster that reads out from the memory and adjusts the phase. Further, the amount of phase change corresponding to the motor rotation speed may be set using an arithmetic circuit that approximates the external force / displacement transfer characteristic of the magnetic bearing.
• the invention according to claim 8 is characterized in that a signal switch for turning on and off a signal flow in the second control unit is compared with the sensor signal and a reference signal, and based on a result of the comparison.
• a third control unit for turning on / off the signal switch is further provided.
• a signal switch for turning on / off a signal flow in the second control unit, a comparator for comparing an actual rotational speed signal with a reference signal, and the signal switch
• a fourth control unit including a signal generator for generating a command signal for turning on and off is further provided.
• a second rotational frequency component extractor is provided at a stage subsequent to the signal forming device including the comparison unit of the second control unit.
• the output signal from the second control unit can be a low-order sine wave obtained by removing its harmonic components from a rectangular wave, and it is possible to prevent disturbances such as noise generation due to harmonics. it can.
• the sensor output before turning on the signal switch in the second control unit and the sensor output when turning on the signal switch are compared, and the It is preferable to provide a fifth control unit for outputting a command value for changing the gain set value.
• the gain of the gain regulator can be set to an appropriate value, and the gain suitable for suppressing whirling can be obtained. Can be given.
• FIG. 1 is a diagram showing a basic configuration of a conventional control type magnetic bearing device.
• FIG. 2 is a diagram showing a basic configuration of the control type magnetic bearing device according to the embodiment of the present invention.
• FIG. 3 is a block diagram showing a model of the control system in FIG.
• FIG. 4 is a diagram showing the configuration of the second control unit in FIG.
• FIG. 5 is a diagram illustrating a circuit configuration example of a buffer amplifier, a frequency component extractor, and a phase adjuster.
• FIG. 6 is a diagram showing an example of a circuit configuration of a signal former and a gain adjuster and signal waveforms of respective parts.
• FIG. 7 is a diagram showing a modified example of the signal former.
• FIG. 8 is a diagram showing a configuration example of a second control unit having a signal switch for turning a signal on and off.
• FIG. 9 is a diagram illustrating a circuit configuration example of the third control unit.
• FIG. 10 is a diagram showing a configuration example of a control unit for turning on / off a signal by a fourth control unit.
• FIG. 11 is a diagram showing a configuration example when a second frequency component extractor is provided in the second control unit.
• FIG. 12 is a diagram showing a configuration example of a control type magnetic bearing device provided with a fifth control unit for adjusting a gain.
• FIG. 13 is a diagram showing a configuration example of a control type magnetic bearing device provided with a sixth control unit capable of handling a wide speed range.
• FIG. 14 is a diagram showing a configuration example in the sixth control unit.
• FIG. 15 is a diagram showing a configuration example of a phase adjuster capable of supporting a wide speed range.
• Figure 16 is a diagram showing the configuration of a wafer spin dryer supported by magnetic bearings.
• Fig. 17 is a diagram showing an example of force / displacement transfer characteristics of the servo control system of the radial magnetic bearing.
• Figure 18 shows the test results equivalent to open balance control.
• Fig. 18B shows the control output signal, showing the case where the control is off.
• Fig. 19 shows the test results equivalent to open balance control.
• Fig. 19B shows the control output signal, showing the case where control is on.
• FIG. 20 is a diagram showing a test result equivalent to the open balance control.
• FIG. 2OA shows a displacement sensor output
• FIG. 20B shows a control output signal, and shows a case where control is off.
• Fig. 21 shows the test results equivalent to open balance control.
• Fig. 21 A shows the displacement sensor output
• Fig. 21 B shows the control output signal, and shows the case where the control is on.
• FIG. 22 is a diagram showing test results by the control unit of the present invention.
• FIG. 22A shows a displacement sensor output
• FIG. 22B shows a control output signal, and shows a case where control is off.
• FIG. 23 is a diagram showing test results according to the present invention.
• FIG. 23A shows a displacement sensor output
• FIG. 23B shows a control output signal, and shows a case where control is on.
• FIG. 24 is a diagram showing the test results according to the present invention, and is a diagram showing the output of the displacement sensor when the control of the X axis and the Y axis is on.
• FIG. 25 is a diagram showing test results according to the present invention, and is a diagram showing displacement sensor outputs when the control of the X axis and the Y axis is turned off from the control off.
• FIG. 26 is a diagram illustrating an example of the frequency characteristics of the gain and the phase of the control circuits illustrated in FIGS. 2 to 6.
• FIG. 27 is a diagram illustrating a configuration example of a second control unit according to another embodiment of the present invention.
• FIG. 28 is a diagram showing experimental data of a steep rise / fall and whirling characteristics of a rotating body during high-speed rotation in a wafer spin driver using the second control unit shown in FIG. 27. .
• FIG. 29 shows other experimental data of the steep rise / fall and the whirling characteristics of the rotating body during high-speed rotation in a wafer spin driver using the second control unit shown in Fig. 27.
• FIGS. 2 to 29 the same reference numerals indicate the same or corresponding parts.
• FIG. 2 shows a basic configuration of the control type magnetic bearing device according to the embodiment of the present invention.
• a part of the bearing device that supports the radial direction of the rotating shaft 1 is extracted for easy understanding, and X-Y orthogonal to the rotating shaft 1 is taken out.
• An example will be described in which the vibration amplitude of the rotating body 1 along the X-axis direction of the axial plane (cross section) is controlled.
• the horizontal axis is the X axis
• the vertical axis is Y
• the displacement sensors 2a and 2b and the electromagnetic stones 3a and 3b are arranged so that the rotating body 1 is sandwiched on the X-axis, and electric power is supplied based on the sensor signals of the displacement sensors 2a and 2b.
• the current supplied to the magnets 3a and 3b is controlled, the electromagnet and the displacement sensor are similarly arranged at the position sandwiching the rotating body 1 on the Y-axis, and are similarly controlled.
• displacement sensors 2 a and 2 b which are arranged at positions sandwiching the rotation axis 1 on the X axis and detect the radial displacement of the rotation axis 1 are connected to the sensor amplifier 4.
• the displacement sensors 2a and 2b and the sensor amplifier 4 constitute a displacement sensor unit.
• the output signal of the sensor amplifier 4 is an electric signal (sensor signal) corresponding to the displacement of the rotating body 1 along the X-axis direction.
• This sensor signal is input to a first control unit 5 and a second control unit 7 arranged in parallel with the first control unit 5.
• the first control unit 5 calculates the first control signal based on the sensor signal and outputs it as a control current
• the second control unit 7 changes the phase of the sensor signal from the second signal.
• the control signal is generated and output as a control current.
• the first and second control signals (control currents) are combined (added) by the signal combiner 8, and the combined control signal is supplied to each of the electromagnets 3a and 3b. It is amplified by the amplifiers 6a and 6b and supplied to the coils of the electromagnets 3a and 3b, respectively.
• the second control unit 7, the power amplifiers 6a and 6b, the electromagnets 3a and 3b, and the magnetic bearing are modeled and shown in a block diagram.
• magnetic bearing from the mass M and the magnetic bearing engagement stiffness K u of the rotating body, is represented as the most simple system with function numbers as shown (1 / MS 2, K) . In this function, S indicates Laplace operator.
• FIG. 4 shows an example of the configuration of the second control unit, the software 7.
• the second control unit 7 is composed of a noise amplifier 7a, a rotational frequency component extractor 7b, a phase (phase shift) adjuster 7c, and a signal former 7d including a comparator. And a gain adjuster 7e.
• the rotational frequency component is extracted from the sensor signal amplified by the noise amplifier 7a by the rotational frequency component extractor 7b, which is a filter, and the phase of the extracted signal is adjusted by the phase adjuster 7c.
• the output signal of the phase adjuster 7c and the reference potential are compared by a comparator to form a signal swinging in the positive and negative directions with respect to 0 V, and the amplitude is adjusted by the gain adjuster 7e.
• the resulting signal is output to the signal combiner 8. That is, by passing the sensor signal through the rotation frequency signal extractor 7b, a signal component corresponding to the motor rotation speed is extracted, and an arbitrary phase (phase shift) adjustment amount is given by the phase adjuster 7c.
• the signal generator 7d including the comparator the frequency and phase information corresponding to the motor rotation speed of the signal are transmitted to the downstream, but the amplitude information is cut off. I have. Since this signal processing is necessary, a signal generator 7 d that includes a comparator is used.
• FIG. 5 shows a specific circuit configuration example of the buffer amplifier 7a, the rotational frequency component extractor 7b, and the phase adjuster 7c of the second control unit 7.
• each of these devices is simply composed of a general-purpose operational amplifier and CR elements. That is, the buffer amplifier 7a is an amplifier using an operational amplifier, and the rotational frequency component extractor 7b is composed of an operational amplifier and a CR element. It is a filter circuit that combines.
• the phase adjuster 7c is a circuit in which the operational amplifier and the CR element are combined, and the phase amount can be adjusted by adjusting the volume connected to the ground side. .
• a sine wave of a frequency component synchronized with the sensor signals from the displacement sensors 2a and 2b is extracted, and the phase is adjusted by adjusting the volume of the phase adjuster 7c. That is, by adjusting the volume of the variable resistor, the phase can be adjusted from 0 to 180 [deg].
• FIG. 6 shows an example of a circuit configuration of the signal generator 7d including the comparator and the gain adjuster 7e, and a signal waveform of each part.
• the signal former 7 d is a circuit in which comparators 7 la and 7 1 b and operational amplifiers 7 2 a and 7 2 b that perform sign inversion are used, as shown in FIG.
• the output signal swings to the + and-sides with respect to V (ground potential).
• the gain adjuster 7e is an amplifier including an operational amplifier 72c.
• the output from the phase adjuster 7c is a sine wave as shown in 1 and branches into two.
• One signal is compared with the reference potential by the comparator 7 la, and the signal is rectangular as shown in 2.
• a wavy waveform is output.
• the other signal is input to the inverter 72a and the comparator 7lb, and a rectangular waveform is obtained whose waveform is inverted from that of 2 as shown in 3.
• this waveform is further inverted by the inverter 72b, so that the waveform becomes as shown by 4.
• the amplitude is adjusted by the amplifier 72c of the gain adjuster 7e and synthesized, thereby forming a rectangular wave which swings up and down around the ground potential as shown in 5.
• the gain adjuster 7e also serves as the gain adjuster 7e provided in the power amplifier circuit that drives the electromagnet in the conventional control device shown in FIG.
• the second control unit 7 provides information on the frequency and phase of the sensor signal.
• the signal whose phase has been adjusted is output and added to the signal of the first control unit 5 by the signal combiner 8. Therefore, information on the amplitude of the sensor signal is not transmitted to the downstream side.
• the rotation frequency signal extractor 7b of the second control unit 7 may be, for example, a band-pass filter using an analog circuit shown in FIG. 5 or a voltage-tuned band-bus filter of a commercially available functional module.
• This voltage-tuned band-pass filter allows the pass frequency to be adjusted to a center frequency corresponding to an external voltage signal of 0 to 10 (V).
• V 0 to 10
• the described model FLJ-VB etc. correspond to this.
• FIG. 7 is a diagram showing a modification of the signal former 7d. While the signal generator 7d shown in FIG. 6 uses a comparator and several operational amplifiers, in this example, two operational amplifiers, that is, a comparator 77 using operational amplifiers, Similarly, a circuit having an equivalent function can be constituted by an inverting amplifier (inverter) 78 using an operational amplifier.
• inverting amplifier inverter
• the comparator 77 uses a non-linear element having input / output characteristics as shown in FIG. 7B or FIG. 7C.
• a very simple circuit configuration is used, and as shown in FIG.
• a square wave signal ⁇ ⁇ swinging to the positive and negative sides can be formed.
• the configuration can be such that only the frequency component and the phase component of the sensor signal are transmitted to the downstream side, and the amplitude component is not transmitted to the downstream side.
• FIG. 8 shows a signal switch 7f provided after the gain adjuster 7e of the second control unit 7, a third control unit 9 and a sensor signal and a reference signal.
• the signal is compared with the signal, and when the sensor signal is equal to or more than the reference value, that is, when the whirling is larger than a predetermined value (reference value), the signal switch 7f is turned on.
• the signal switch 7f for turning on / off the signal flow in the second control unit 7 is compared with the sensor signals of the displacement sensors 2a and 2b and the reference signal, and the signal switch 7f is compared.
• FIG. 9 shows a configuration example of the third control unit 9.
• the third control unit 9 includes comparators 73a and 73b, inverting amplifiers 74, inverters 75a and 75b-, and an adder 76.
• FIG. 10 includes a fourth control unit 10 that compares a voltage signal proportional to the rotation speed from the motor controller with a reference signal and determines that the signal signal is higher than the reference signal when the voltage signal is equal to or greater than the reference signal.
• the switch 7 f is turned on.
• the fourth control unit 10 is provided in the comparator 10 a for comparing the actual rotational speed signal with the reference signal and in the second control unit 7.
• a signal generator 10b for generating an on / off command signal for a signal switch 7f for turning on / off the flow of the received signal.
• the signal switch 7f in the second control unit 7 is turned on and off with reference to the sensor signal.
• the signal switch 7f in the second control unit 7 is turned on / off based on the rotation speed signal from the controller, that is, when the rotation speed of the motor exceeds a predetermined value. Things can be done.
• FIG. 11 shows a modification of the configuration of the second control unit.
• Figure 11A At the subsequent stage of the gain adjuster 7e in the second control unit 7, a rotational frequency component extractor 7b 'which is a filter having the same function as the rotational frequency signal extractor 7b is provided.
• This makes it possible to convert a rectangular wave signal into a low-order sine wave signal synchronized with the rotation frequency. Therefore, the effect of suppressing the whirling of the rotating body is slightly lower than when the rectangular wave signal is used as the control output and input to the power amplifier, but the current of the harmonic component can be prevented from flowing. It is not necessary to excite the higher order mode.
• Figure 1 1 B are those obtained by rearranging the position of the rotational frequency component extractor 7 b 5 and gain adjuster 7 e in FIG. 1 1 A.
• a signal switch 7f for turning on / off the signal flow shown in FIG. 8 is provided in the second control unit 7.
• the rotation frequency signal extractors 7 b and 7 b ′ in the second control unit 7 are connected to the natural frequency.
• Fig. 12 shows the fifth control unit 11, which is equipped with a fifth control unit 11. It observes sensor signals and turns on and off the signal switch 7f of the second control unit 7.
• the amplitude of the sensor signal in the state is compared, and the magnitude of the gain adjuster 7e is set. That is, the fifth control unit 11 detects the amplitude of the sensor output when the signal switch 7 f of the second control unit 7 is in the off state and the signal control when the signal switch 7 f is turned on. It is configured to compare the amplitude of the sensor output with the gain setting value of the gain adjuster 7e. As a result, when the motor rotation speed reaches a predetermined value or more, the switch 7 f is turned on by the third control unit 9 and the whirling is suppressed, but the gain adjuster 7 e It is possible to set an appropriate gain for the target. Therefore, whirling can be suppressed more effectively.
• FIG. 13 shows a sixth control unit 12 provided with a voltage signal and a sensor which are proportional to the rotation speed from the motor controller.
• a signal is input, and a phase adjustment value is set in advance for each rotation speed, and a phase adjustment amount corresponding to the motor rotation speed is set in the phase adjuster 7c.
• a filter circuit capable of changing the frequency by changing the voltage value is used as the rotation frequency component extractor 7b. This makes it possible to extract frequency components corresponding to the motor rotation speed.
• FIG. 14 shows the storage unit that measures and stores the transfer characteristic (gain, phase) data of the displacement sensor output signal with respect to the power amplifier input signal in the conventional servo control configuration.
• the phase adjustment amount corresponding to the motor rotation speed is read from the stored data and set in the phase adjuster 7c as the phase adjustment amount.
• FIG. 15 shows a modification of the sixth control unit 12.
• the sixth control unit shown in Fig. 14 has data on the transfer characteristics of the magnetic bearings stored in its memory, whereas the sixth control unit shown in Fig. 15 has the transfer characteristics of the magnetic bearings. This is simulated with an analog circuit.
• Fig. 15A two stages of primary filter circuits consisting of an operational amplifier and a CR element are used to form the gain characteristics in Fig. 15B and the phase characteristics in Fig. 15C.
• C The capacitance element C 'is used to reduce the wide-area gain and stabilize the operation of the operational amplifier.
• This circuit configuration is also commonly used as a differential element (phase lead circuit) for ordinary PID control.
• the characteristics shown in FIGS. 15B and 15C simulate the transfer characteristics of the magnetic bearing shown in FIG. 17 described later. For example, a phase change of about 90 to 100 deg can be given to 50 Hz, and a phase change of about 65 deg can be given to 25 Hz. And figure in this range As shown, the gain is almost flat.
• Fig. 16 shows a prototype of a magnetic levitation spin dryer as an example of the structure of a motor body supported by magnetic bearings.
• the radial magnetic bearing 32 in the figure is used.
• a rotating shaft 15 is supported in an axial direction and a radial direction by an axial magnetic bearing 33 and a radial magnetic bearing 32, respectively, and is rotated by a motor 31.
• the wafer W is supported on its outer periphery by two beams, two fixed bars and one removable bar. For this reason, the unbalance amount due to the wafer displacement and the unbalance amount due to the deformation of the beam act.
• the denominator is the sensor signal (S) of the displacement sensor
• the numerator is the signal (R) added to the power amplifier input signal for measurement
• the horizontal axis is the frequency axis
• the vertical axis is the gain (gain) and phase ( (Phase).
• the known displacement sensor sensitivity is multiplied by a constant: Ks (V / m), a power amplifier gain: Kd (A / V), and an electromagnet gain: Kc (N / A).
• Ks V / m
• Kd A / V
• Kc electromagnet gain
• the frequency range actually operated as a spin dryer is 0 to 50 Hz (0 to 3000 min- 1 ), and the phase characteristics are 108 deg at 50 Hz and 65 deg at 25 Hz. It turns out that it is a value of about. What we want to focus on here is the phase characteristics, that is, the phase information at the rotational operating frequency. This phase information is the basis of the adjustment amount set in the phase adjuster in the second control unit.
• FIGS. 18 and 19 show the values estimated based on the phase data shown in FIG. 17 between the control signal and the sensor signal at a rotation speed of 300 min- 1 (50 Hz). That is, the state when a phase difference of approximately 108 (deg) is given is shown.
• Fig. 18 shows the time waveform when the control is off
• Fig. 19 shows the time waveform when the control is on
• Figs. 18A and 19A show the displacement sensor output signal
• Figs. 18B and 19B show the control signal. Show.
• the rotation speed is 3 000 min- 1 (50 Hz)
• the phase difference of approximately 108 (deg) is given between the control signal and the sensor signal, the rotation of the rotating body It turns out that the surroundings are suppressed.
• FIGS. 20 and 21 show the values estimated based on the phase data shown in FIG. 17 between the control signal and the sensor signal at a rotation speed of 1500 min- 1 (25 Hz). That is, the state when a phase difference of about 64.8 (deg) is given is shown.
• Fig. 20 shows the time waveform when the control is off
• Fig. 21 shows the time waveform when the control is on
• Figs. 20A and 21A show the displacement sensor output signal
• Figs. 20B and 21B show the control signal. Show.
• the phase difference of approximately 64.8 (deg) is given between the control signal and the sensor signal at the rotation speed of 1500 min— 1 (25 Hz)
• the rotation of the rotating body is obtained. It turns out that rotation is suppressed.
• FIGS. 22 and 23 show the results of verifying the effect of suppressing the whirling of the rotating body 1 using the control type magnetic bearing device shown in FIGS.
• the rotation speed is 300 min- 1
• Fig. 22 is the time waveform when the control is off
• Fig. 23 is the time waveform when the control is on.
• Figs. 22A and 23A show the displacement sensor output signal.
• 22B and FIG. 23B show control signals, respectively.
• Figure 26 shows the transfer characteristics of the input and output signals of the circuit used in this experiment. From this figure, it can be seen that the phase adjustment amount is advanced by about 90 to 100 deg with respect to 300 min- 1 (50 Hz).
• Figs. 24 and 25 show the results of verification of a case where the unbalanced weight is increased and the conventional servo control causes a downshift.
• a second control unit provided for each of the two servo control systems on the X axis and the Y axis on the XY plane orthogonal to the rotation axis.
• Rotation speed is 3 0 0 0 min 1.
• Fig. 24 shows the control on state
• Fig. 25 shows the time waveform when this control is turned on while the rotor is rotating while the setting is down.
• the upper part shows the X-axis displacement sensor output signal
• the lower part shows the time waveform of the Y-axis displacement sensor output signal.
• the effect of suppressing whirling can be confirmed. Comparing the phase amounts used in these two experiments with the phase data shown in Fig. 1 ⁇ , it can be seen that they are about 20% larger. Further, as shown in FIG. 12, the whirling amplitude can be suppressed by adjusting the setting of the gain adjuster in the second control unit. The upper limit of the action is determined by the basic performance of the power amplifier and the magnetic saturation of the magnetic path of the electromagnet.
• FIGS. 27 to 29 show that the whirling of the rotator can be sufficiently suppressed in the wafer spin dryer shown in FIG. 16 according to the circuit configuration of the present invention even when the rotation speed fluctuates steeply.
• FIG. 27 shows a configuration example of the second control unit 17.
• the sensor signal (input) is amplified by the buffer amplifier 17a, and the signal component corresponding to the rotation speed is extracted by the rotation speed same signal extractor 17b.
• the extractor 17b for example, a model VT-2 BPA manufactured by NF Circuit Design is used.
• the amount of phase adjustment is given by the phase adjuster 17c.
• the amplitude information is cut off, and only the frequency and phase information corresponding to the motor rotation speed are transmitted to the downstream side ( and the gay).
• the gain is adjusted by the gain adjusters 17e and 17f, added to the signal output of the first control unit 5, and the control current is supplied to the electromagnet.
• e is a fixed gain regulator independent of the rotation speed.
• the gain regulator 17 f is a rotation speed proportional gain regulator that gives the gain proportional to the rotation speed. Model AD 6 3 3 is used.
• Fig. 28 shows the case where the rotation speed rises sharply from zero to a predetermined speed, runs at a high speed (predetermined speed) of about 2400 mirr 1 for a certain period of time, and then suddenly decelerates and stops. Rotational run-out of wafer spin dryer The surrounding situation is shown.
• the whirling of the rotating body may have enough room for the TD (Touch Down) level even at the sharp rise C
• the balance control is turned off during high-speed rotation, the whirling of the rotating body increases to the TD (Touch Down) level as shown in the displacement sensor outputs of FIGS. 28A and 28B.
• FIG. 29 shows the whirling state of the rotating body at the time of steep rising and falling similar to FIG.
• the rotation speed is increased to 300000 mirr 1 .
• the whirling of the rotating body has a sufficient margin more than the TD (Touch Down) level, and it can be seen that the whirling is sufficiently suppressed.
• the balance control is turned off, the whirling becomes large to the TD (Touch Down) level at the time of a steep rise.
• the displacement sensor (No. 1) is a sensor provided on the radial magnetic bearing closer to the wafer holder, and the displacement sensor (No. 2) is provided on the radial magnetic bearing remote from the wafer holder. It is a sensor.
• the motor is a 2-pole induction motor
• Radial external force is generated.
• the input power to the motor increases in order to maintain the rotational movement that follows the load fluctuation.
• Excessive radial external force is generated.
• contact bearings cannot be used, and the above problems may be encountered when magnetic bearings are applied to rotating machines for special environments.
• the amount of unbalance caused by the object to be dried may be excessively large as compared with the usual rigidity for supporting a magnetic bearing.
• the present invention relates to a control device for a magnetic bearing, which uses a magnetic bearing as a means for supporting a rotating body. Therefore, for example, it can be used as a control device for a magnetic bearing that magnetically levitates and supports the rotating shaft of a magnetically levitated spin driver used in the manufacture of semiconductor devices.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Magnetic Bearings And Hydrostatic Bearings (AREA)

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• 1999
  • 1999-05-25 JP JP14470199A patent/JP4036567B2/ja not_active Expired - Lifetime
• 2000
  • 2000-01-21 DE DE60042253T patent/DE60042253D1/de not_active Expired - Fee Related
  • 2000-01-21 KR KR1020007010700A patent/KR100622098B1/ko not_active Expired - Fee Related
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• 2002
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