JP4674514B2 - DC brushless motor device and rotary vacuum pump - Google Patents

Description

  The present invention relates to a DC brushless motor device and a rotary vacuum pump equipped with the DC brushless motor device.

  The turbo molecular pump (TMP) performs evacuation by rotating at high speed a rotor on which rotor blades are formed with respect to fixed blades. A DC brushless motor is known as a motor for rotating the rotor. In general, in a DC brushless motor, a Hall element is used to detect the magnetic position of the rotor and detect the rotational position of the rotor.

  However, since the Hall element is inferior in radiation resistance and heat resistance to other parts of the pump body, a technique using an inductance sensor instead of the Hall element has been proposed (for example, see Patent Document 1). In this method, instead of directly detecting the magnetic pole of the motor rotor, a target having a concavo-convex surface is mounted on the rotating shaft, and an inductance sensor is arranged so as to face the concavo-convex surface to detect a change in the distance to the target. To detect the rotational position.

JP 2001-231238 A

  However, in the inductance sensor method as described above, when the target is fixed to the rotating shaft, it is necessary to accurately match the phase of the magnetic pole position of the motor rotor and the target. It was difficult to match.

  In order to solve such a problem, the present inventor in Japanese Patent Application No. 2005-145324 corrected the synchronization signal obtained in synchronization with the rotation of the motor rotor on the basis of the rotational speed information and the phase difference information. Is proposed, and a motor drive signal is generated from the rotational position signal.

  By the way, the calculation of such a rotational position signal needs to increase the rotational speed to such an extent that a stable rotational frequency can be obtained, and it has been necessary to rotate asynchronously until such rotational speed is reached. However, when driven completely asynchronously, sufficient rotational torque may not be obtained, and when the rotor weight is heavy, there is a possibility that acceleration cannot be achieved to the extent that a stable rotational frequency can be obtained.

According to the first aspect of the present invention, a rotation energization pattern, which is a combination pattern of applied voltages of each phase of the motor stator, is generated according to a plurality of rotor rotation positions, and each phase application by the rotation energization pattern is synchronized with the magnetic pole position. Applied to a DC brushless motor device that applies a voltage to each phase to rotationally drive the motor rotor, a signal generating means for generating a synchronization signal synchronized with the rotation of the motor rotor, a rotational position signal and a synchronization signal representing the magnetic pole position of the motor rotor Phase difference storage means for storing phase difference information in advance, rotation speed detection means for detecting rotation speed information of the motor rotor based on the synchronization signal, and synchronization signal obtained during rotation of the motor rotor. A signal operation for calculating the rotational position signal by correcting based on the phase difference information stored in the phase difference storage means. And means, until the motor rotor reaches a predetermined rotational speed, generated asynchronously multiple rotation energization pattern to the rotation of the motor rotor, the motor rotor reaches a predetermined rotational speed, synchronized multiple rotation energization pattern to the rotation of the motor rotor A rotation energization pattern generating means that generates the state, a state change detection means that detects whether or not the state of the synchronization signal has changed, and a rotor rotation that detects a change in the state of the synchronization signal among the plurality of energization patterns for rotation Based on the pattern storage means storing a predetermined energization pattern for rotation (hereinafter referred to as a storage pattern) associated with the position and the energization pattern for rotation generated by the energization pattern generation means for rotation, the motor rotor from a stopped state until a predetermined rotational speed performs asynchronous control for rotating the motor rotor asynchronously to the rotation of the motor rotor When the motor rotor exceeds the predetermined rotational speed, and a motor starting control means for performing synchronous control for rotating the motor rotor in synchronism with the rotation position signal of the motor rotor, in (a) asynchronous control, a predetermined rotational speed from the motor rotor is stopped Until the rotation of the motor rotor, the application voltage of each phase corresponding to a plurality of rotation energization patterns is applied to each phase asynchronously with the rotation of the motor rotor, and the motor rotor is driven to rotate. Each time it is detected, the generation order of the plurality of energization patterns for rotation is controlled to be the order generated from the storage patterns stored in the pattern storage means. In (b) synchronization control, the signal calculation means Based on the calculated rotational position signal, each phase applied voltage according to the energization pattern for rotation is repeated in synchronization with the rotation of the motor rotor. Device to be applied to each phase, characterized by Rukoto motor rotor is rotated.
According to a second aspect of the present invention, the DC brushless motor device according to the first aspect further comprises a preparation processing means for storing the memory pattern in the pattern storage means prior to the motor start, and the preparation processing means comprises a plurality of rotation-use devices. When a change in the state of the synchronization signal is detected by the rotation control means for rotating the motor rotor by a predetermined angle by sequentially applying the voltage of the energization pattern and the state change detection means, the generation order is higher than the rotation energization pattern at the time of detection. And a storage control means for storing the subsequent energization pattern for rotation in the pattern storage means as a storage pattern.
According to a third aspect of the present invention, in the DC brushless motor device according to the first aspect, the plurality of rotation energization patterns each include two N (N is a positive integer) types of rotation energization patterns, and The DC brushless motor device further comprises one of the same energizing patterns for rotation that are generated in the same order. For the inspection to generate 2N energization patterns (hereinafter referred to as inspection energization patterns) different from the 2N rotation energization patterns by replacing the energization patterns for rotation before and after that with the energization patterns in an intermediate state that are alternately repeated. An energization pattern generating means; and a preparation processing means for storing the storage pattern in the pattern storage means prior to motor start. When a change in the state of the synchronization signal is detected by the rotation control unit that sequentially applies the voltages of the N inspection energization patterns and rotates the motor rotor by a predetermined angle and the state change detection unit, the inspection energization pattern at the time of detection And a storage control means for storing in the pattern storage means the energization pattern for rotation having the same generation order as the energization pattern for inspection two generation orders later than the storage order.
According to a fourth aspect of the present invention, in the DC brushless motor device according to any one of the first to third aspects, a phase difference calculation means for calculating phase difference information based on a back electromotive voltage of at least one phase of the motor stator. The phase difference storage means stores the phase difference information calculated by the phase difference calculation means.
A rotary vacuum pump according to a fifth aspect of the invention is characterized in that the DC brushless motor device according to any one of the first to fourth aspects is provided as a rotational drive means of a pump rotor.

  According to the present invention, every time the synchronization signal is generated, the energization pattern is replaced with the energization pattern stored in the pattern storage means, and the generation is performed in order. Acceleration torque can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a DC brushless motor device according to the present invention, and is a block diagram showing a schematic configuration of a magnetic bearing type turbo molecular pump in which the DC brushless motor device is incorporated. The turbo molecular pump includes a pump body 1 and a power supply device 2. In the example shown in FIG. 1, the pump main body 1 and the power supply device 2 are configured to be connected by a cable. However, the pump main body 1 and the power supply device 2 may be configured integrally.

  The pump body 1 is provided with a rotor 4 formed with rotor blades (described later). The rotor 4 is supported in a non-contact manner by a magnetic bearing 5 and is rotated by a motor 6. A DC brushless motor is used as the motor 6. On the other hand, the power supply device 2 includes a motor control unit 7 that drives a motor 6 (DC brushless motor) and a bearing control unit 8 that controls an excitation current supplied to the magnetic bearing 5.

  FIG. 2 is a cross-sectional view showing details of the pump body 1. The rotor 4 disposed inside the casing 10 of the pump body 1 is formed with a plurality of stages of rotary blades 41 and a screw rotor portion 42. Fixed blades 43 are alternately arranged between the stages of the rotary blades 41 arranged vertically. Further, a screw stator portion 44 is disposed on the base 3 so as to face the rotating screw rotor portion 42.

  A motor rotor 62 of the DC brushless motor 6 is mounted on the shaft portion 45 of the rotor 4, and a permanent magnet is built in the motor rotor 62. On the other hand, a motor stator 61 having a U-phase winding, a V-phase winding, and a W-phase winding for forming a rotating magnetic field is provided on the base 3 side. A sensor target 46 is provided at the lower end of the shaft portion 45, and a rotational position sensor 47 is provided at a position facing the sensor target 46.

  The rotational position sensor 47 is a distance sensor that detects a distance from the sensor target 46, and an inductance sensor is used in the present embodiment. The rotation position sensor 47 is not limited to that described above as long as it outputs a signal synchronized with the rotor rotation, and an optical encoder or the like may be used.

  The magnetic bearing 5 (see FIG. 1) for supporting the rotor 4 in a non-contact manner includes electromagnets 51 and 52 constituting a radial magnetic bearing and an electromagnet 53 constituting an axial magnetic bearing as shown in FIG. A shaft control type magnetic bearing is constructed. Corresponding to the radial electromagnets 51 and 52 and the axial electromagnet 53, radial displacement sensors 55 and 56 and an axial displacement sensor 57 for detecting the position of the rotor 4 are provided. 11 and 12 are emergency mechanical bearings, and 13 is a connector to which a cable connecting the pump body 1 and the power supply device 2 is connected.

  FIG. 3 is a block diagram showing a schematic configuration of the motor stator 61, the motor rotor 62, the sensor target 46, the rotational position sensor 47, and the motor control unit 7 constituting the DC brushless motor device. The motor control unit 7 includes a rotation pulse generation unit 70, a power source 71, a motor drive waveform generation circuit 72, a signal delay unit 73, a rotation speed detection unit 74, a delay time calculation unit 75, a phase difference storage unit 76, a difference calculation unit 77, A phase difference measuring unit 78 and a pattern storage unit 79 are provided. A drive voltage is applied to a U-phase winding, a V-phase winding, and a W-phase winding provided in the motor stator 61 by a motor drive waveform generation circuit 72 connected to a power source 71.

  In FIG. 2, the rotational position sensor 47 is disposed in the axial direction (downward in the drawing) of the sensor target 46, but FIG. 3 shows the case where the rotational position sensor 47 is disposed in the radial direction of the sensor target 46.

  4A and 4B are diagrams showing the positional relationship between the rotational position sensor 47 and the sensor target 46. FIG. 4A shows the case where the rotational position sensor 47 is arranged in the axial direction of the sensor target 46, and FIG. 4B shows the rotational position. The case where the sensor 47 is arranged in the radial direction of the sensor target 46 is shown. In the case of FIG. 4A, the lower surface of the sensor target 46 is an uneven surface having a level difference h, and the convex surface 46a and the concave surface 46b are distributed by 180 degrees with respect to the rotation angle.

  On the other hand, when the rotational position sensor 47 is arranged in the radial direction as shown in FIG. 4B, the convex surface 46a and the concave surface 46b of the step h are formed on the outer peripheral surface of the sensor target 46 that is the sensor facing surface. Yes. From the rotational position sensor 47, a signal corresponding to the change in inductance due to the step h is output to the rotational pulse generator 70. The rotation pulse generator 70 generates a rotation pulse signal G as shown in a time chart of FIG. The rotational pulse signal G is in a high (H) state when the rotational position sensor 47 is opposed to the convex surface 46a of the sensor target 46, and conversely is in a low (L) state when it is opposed to the concave surface 46b.

<Description of calculation method of rotational position signal>
In the present embodiment, the synchronization signal obtained in synchronization with the rotation of the motor rotor 62 is corrected based on the rotational speed information and the phase difference information, and a correct rotational position signal is calculated. First, a method for calculating a correct rotational position signal will be described. In FIG. 3, the rotation pulse signal G output from the rotation pulse generation unit 70 is input to the signal delay unit 73, the rotation speed detection unit 74, and the phase difference measurement unit 78. Based on the rotation pulse signal G and the drive voltage applied to the motor stator 61, the phase difference measuring unit 78 determines the position of the step 46c of the sensor target 46 and the position of the boundary surface between the N pole and S pole of the motor rotor 62. Is calculated (hereinafter referred to as phase angle θ). The calculated phase angle θ is stored in the phase difference storage unit 76. The phase angle θ is caused by an assembly error or the like when the sensor target 46 is fixed to the shaft portion 45 (see FIG. 2). A method for calculating the phase angle θ will be described later.

  The rotation speed detection unit 74 calculates the rotation frequency f of the motor rotor 62 based on the rotation pulse signal G of the rotation position sensor 47 and outputs the calculated rotation frequency f to the delay time calculation unit 75. Further, the rotation cycle T1 = 1 / f is calculated from the obtained rotation frequency f, and the energization pattern switching time T1 / 6 obtained by dividing the rotation cycle T1 into 6 is input to the motor drive waveform generation circuit 72.

The delay time calculation unit 75 rotates the rotation position signal S representing the magnetic pole position and the rotation based on the phase angle θ stored in the phase difference storage unit 76 and the rotor rotation frequency f calculated by the rotation speed detection unit 74. A delay time Δt (see FIG. 5) with the pulse signal G is calculated based on the following equation (1).
Δt = (1 / f) · (θ / 360) (1)

  The delay time Δt calculated by the delay time calculation unit 75 is input to the signal delay unit 73. The signal delay unit 73 generates a correct rotation position signal S based on the input rotation pulse signal G and the delay time Δt, and outputs the rotation position signal S to the motor drive waveform generation circuit 72. The motor drive waveform generation circuit 72 applies a drive voltage to each winding (U, V, W) of the motor stator 61 based on the input rotational position signal S and energization pattern switching time T1 / 6.

  FIG. 5 is a diagram for explaining an energization pattern of the drive voltage. In the rotation pulse signal G output from the rotation pulse generation unit 70, the rotation position signal S output from the signal delay unit 73, and the U, V, and W phases. It is a time chart which shows the applied voltage. The cycle of the rotation position signal S in the first cycle in FIG. 5 is the same as the cycle T1 of the rotation pulse signal G calculated by the rotation speed detection unit 74, but is generated with a delay of Δt. Further, the rotation position signal S of the next cycle rises with a delay of Δt from the rise of the rotation pulse signal G (cycle T2) of the second cycle.

  The motor drive waveform generation circuit 72 starts generating the energization pattern in synchronization with the rising edge of the rotation position signal S in the second cycle. The switching of the energization pattern is performed based on the energization pattern switching time T1 / 6 input from the rotation speed detection unit 74. Further, the rotational position signal S in the third period rises with a delay of Δt with respect to the rotational pulse signal G in the third period, and an energization pattern is generated in synchronization with the rise of the rotational position signal S.

  The cycle of the rotation signal S in the second cycle is equal to the cycle T2 of the rotation pulse signal G in the second cycle. However, since the rotor rotational speed changes during acceleration and deceleration, it is generally the same as the cycle T1 of the first cycle. T2 ≠ T1. In the example shown in FIG. 5, T2 <T1 (acceleration state). Therefore, the duration of the sixth energization pattern of the signal waveform in the first cycle is shorter than T1 / 6.

  In this way, the rotation pulse signal G output from the rotation position sensor 47 is corrected by the delay time Δt calculated from the rotation frequency f and the phase angle θ to calculate a correct rotation position signal S, and the rotation position signal S By generating the energization pattern in this manner, even if the phase angle θ is generated between the magnetic pole position of the motor rotor 62 and the rotation pulse signal G, synchronous driving is possible. As a result, when the sensor target 46 is fixed to the shaft portion 45, the position of the stepped portion 46c does not need to be exactly matched with the position of the boundary surface between the N pole and the S pole of the motor rotor 62, and the assembly work is made more efficient. Can be achieved.

  In order to calculate the phase angle θ, it is necessary that the motor rotor 62 is rotated at a rotation speed at which the rotation speed detector 74 can calculate a stable rotation frequency f. Therefore, at the time of start-up, a drive voltage similar to the energization pattern as shown in FIG. 5 is generated asynchronously regardless of the magnetic pole position of the motor rotor 62, and the cycle is sequentially shortened so that the rotor 4 has a predetermined rotational speed. Accelerate to. When the rotor rotation speed reaches a predetermined rotation speed at which a stable rotation frequency f can be acquired by the rotation speed detection unit 74, the operation shifts to the synchronous operation as described above.

[Description of Calculation Method of Phase Difference Angle θ]
Next, a method for calculating the phase angle θ in the phase difference measuring unit 78 will be described. In order to calculate the phase angle θ, first, the motor rotor 62 in a stopped state is started asynchronously as described above, and once the predetermined rotational speed is reached, the drive voltage is turned off once. The difference calculation unit 77 receives the back electromotive voltage induced in the U phase and the neutral point voltage, and “(difference) = (back electromotive voltage) − (neutral point voltage)” is calculated there. FIG. 6A is a diagram showing an example of the difference signal, and shows one period of the periodic difference signal, that is, one rotation of the rotor. Here, since a two-pole motor is described as an example, the positive / negative of the difference signal appears once every rotation.

The phase difference measuring unit 78 detects a point (zero cross point) at which the difference signal becomes zero. It is conventionally known that there is a phase difference of 30 degrees in angle between the zero cross point P and the rotational position signal S detected by a conventional Hall sensor or the like. On the other hand, the rotation pulse signal G (see FIG. 6C) input to the phase difference measuring unit 78 is out of phase with the difference signal in FIG. Therefore, the phase difference measuring unit 78 has a time difference T between the timing at which the zero cross point P is detected and the rising timing of the rotation pulse signal G, a predetermined phase difference of 30 degrees, and the rotation detected by the rotation speed detecting unit 74. Based on the period T1, the phase difference θ (= phase angle θ) between the rotation pulse signal G and the rotation position signal S is calculated by the following equation (2).
θ = (T / T1) × 360-30 (2)

  This phase difference θ is stored in the phase difference storage unit 76 as the phase angle θ. Once the phase angle θ is acquired, the rotation position signal S is generated by the signal delay unit 73 as described above, and the motor is driven in synchronization with the magnetic pole position of the motor rotor 62. The method for obtaining the zero cross point described above is the same as the method used in the conventional sensorless motor, but in this embodiment, the motor drive voltage is turned off and the back electromotive force is measured. Therefore, switching noise or the like during PWM driving is not superimposed, and the timing of the zero cross point can be easily acquired with a simple circuit configuration.

  That is, the rotational position sensor 47 is a cost increase factor as compared with the conventional sensorless driving method, but since the control system is simplified, there is a total cost reduction effect. In addition, the control itself becomes simpler than the sensorless case, and the stability is improved.

In the above-described embodiment, the U-phase counter electromotive voltage is used, but a V-phase or W-phase counter electromotive voltage may be used. Also, the counter electromotive voltage of one of the U, V, and W phases is measured, and an intermediate voltage (Vmax−Vmin) / 2 between the maximum value Vmax and the minimum value Vmin (= 0 V) is obtained. The timing at which the measured back electromotive voltage coincides may be used instead of the zero cross point described above. In that case, the phase difference θ is calculated by the equation (2) as described above. Furthermore, a difference between the back electromotive voltages of the two phases, for example, a difference between the U phase back electromotive voltage and the V phase back electromotive voltage may be used. In that case, the phase difference θ is calculated by the following equation (3).
θ = T / T1 × 360 (3)

《Explanation on improved starting method》
In the above-described example, the control has been described in which the magnetic field of the rotor stator 61 is asynchronously rotated at the time of start-up, and is accelerated asynchronously to such an extent that the phase angle θ can be calculated. However, when driven completely asynchronously, a sufficient rotational torque cannot be obtained, and if the weight of the rotor 4 is heavy, there is a possibility that acceleration cannot be performed to the extent that the phase angle θ can be calculated. Therefore, in the present embodiment, rotation control as described below is performed so that even a heavy rotor 4 can be reliably accelerated.

[First example]
7 and 8 are diagrams illustrating a first example of an improved starting method. First, the voltage of the energization pattern (1) in FIG. 7 is applied to each U, V, W phase of the motor stator 61, and the state is maintained. Motor rotor 62 that has been stopped is rotated slowly given magnetic field therefore the rotational torque of the motor stator 61, and stops at a position that balances the force of the stator magnetic field.

  During this time, it is detected whether or not the state of the rotation pulse signal G has changed from off to on. In the example shown in FIG. 7, the rotation pulse signal G is in an off state. In addition, the arrow of FIG. 7 has shown the direction through which an electric current flows. For example, in the energization pattern (1), a current flows from the V phase to the U phase, and in the energization pattern (2), a current flows from the W phase to the U phase.

  Next, the voltage of the energization pattern (2) is applied to each of the U, V, and W phases of the motor stator 61, and the energized state is maintained until the motor rotor 62 stops. As a result, the motor rotor 62 rotates 60 degrees from the stop position of the energization pattern (1) and stops. In the meantime, it is detected whether or not the state of the rotation pulse signal G has changed from off to on. In the example shown in FIG. 7, the rotation pulse signal G changes from off to on. When the rotation pulse signal G changes from OFF to ON as described above, the energization pattern (3) immediately after the energization pattern (2) at that time is stored in the pattern storage unit 79.

  Similarly, the voltages of the energization patterns (3), (4), (5), and (6) are sequentially applied to the U, V, and W phases of the motor stator 61, and wait until the motor rotor 62 stops, It is detected whether or not the state of the rotation pulse signal G has changed from OFF to ON. When the state of the rotation pulse signal G changes from off to on, the energization pattern immediately after the energization pattern at that time is stored in the pattern storage unit 79. When the motor rotor 62 is rotated once in this manner, the rising timing at which the rotation pulse signal G changes from off to on can be detected without fail. In the case of the rotation pulse signal G shown in FIG. 7, a change is detected in the energization pattern (2) as described above, and the energization pattern (3) immediately after the energization pattern (2) is stored in the pattern storage unit 79. Remembered.

  When the above-described storing operation of the energization pattern is completed, the rotation driving of the motor is started. First, a voltage is applied to the motor in a stopped state in the order of the energization patterns (1) to (6). If the rising timing at which the rotation pulse signal G changes from off to on is detected, the energization pattern (3) stored in the pattern storage unit 79 is used regardless of the energization pattern at that time. And then switch to (3), (4), (5). In this case, the time interval of the energization pattern is gradually shortened every time the pattern is switched to accelerate the rotation speed.

  After that, when the period of the rotation pulse signal G can be measured, as shown in FIG. 8, the time obtained by dividing the previous period T1 into six is set as the energization pattern switching time. Thereafter, every time the rising timing of the rotation pulse signal G is detected, replacement with the energization pattern (3) is performed.

  After the shift to drive control with the energization pattern shown in FIG. 8, if the rotational speed has increased to such an extent that the phase angle θ can be calculated, the phase angle θ is calculated as described above. Then, a correct rotational position signal S obtained by delaying the rotational pulse signal G is obtained, and the motor rotor 62 is synchronously driven using the rotational position signal S.

  As described above, in the starting method of the first example, the energization pattern (3) immediately after the energization pattern (2) when the rotation pulse signal G rises from OFF to ON is stored, and when rotating, Since it always starts from the energization pattern (3) after one pattern in synchronism with the rise of the rotation pulse signal G, it is not completely synchronized, but is driven to rotate in a manner that is generally synchronized. Can do.

Therefore, it is possible to improve the rotational torque as compared with the case where the rotational driving is performed asynchronously, and the rotational speed can be accelerated efficiently. As a result, the time from the start to the estimation of the phase angle θ can be shortened, and the shift to the synchronous rotation drive can be made early. Further, since the acceleration performance is improved, the rotation speed at the start of the phase angle estimation can be set to a higher rotation range, and the estimation accuracy can be improved. The reason why the next energization pattern (3) is used for replacing the energization pattern instead of the energization pattern (2) at the rising timing is to obtain an appropriate acceleration.

[Second example]
FIGS. 9-11 is a figure explaining the 2nd example regarding the improved starting method. FIG. 9 is a diagram corresponding to FIG. 7 of the first example, and shows an energization pattern when the timing at which the state of the rotation pulse signal G changes from OFF to ON is detected. In the first example, the motor rotor 62 is rotated by 60 degrees and the rising timing of the rotation pulse signal G is detected. In the second example, the motor rotor 62 is rotated by 30 degrees by switching the energization pattern as shown in FIG. It was made to detect.

  As shown in FIG. 9, there are 12 kinds of energization patterns, and (1) to (6) are the same as the energization patterns (1) to (6) shown in FIG. On the other hand, in the energization pattern (1 ′), the state of the energization pattern (1) and the state of the energization pattern (2) are in an intermediate state in which the current alternately flows, and current flows from the V phase and the W phase to the U phase. It is in a state. That is, the V-phase and W-phase voltages change alternately between E and E / 2. When the V-phase voltage is E, the W-phase voltage is E / 2, and vice versa. When E is E / 2, the W-phase voltage is E.

  In the energization pattern (2 ′), the energization pattern (2) and the energization pattern (3) appear alternately, and a current flows from the W phase to the U phase and the V phase. In the energization pattern (3 ′), the energization pattern (3) and the energization pattern (4) appear alternately, and a current flows from the W phase and the U phase to the V phase. In the energization pattern (4 ′), the energization pattern (4) and the energization pattern (5) appear alternately, and a current flows from the U phase to the W phase and the V phase. In the energization pattern (5 ′), the energization pattern (5) and the energization pattern (6) appear alternately, and a current flows from the U phase and the V phase to the W phase. In the energization pattern (6 ′), the energization pattern (6) and the energization pattern (1) appear alternately, and a current flows from the V phase to the W phase and the U phase.

  When starting the motor rotor 62 from the stopped state, first, a voltage is applied in the energization pattern (1) and the process waits until the motor rotor 62 is stopped. Next, the voltage of the energization pattern (1 ′) is applied. Since the energization pattern (1 ') is in an intermediate state where the energization pattern (1) and the energization pattern (2) appear alternately, the motor rotor 62 is rotated 30 degrees from the position of the energization pattern (1). Will stop in balance.

Next, when the energization pattern is changed from (1 ′) to (2), the motor rotor 62 is balanced at a position rotated 60 degrees from the position of the energization pattern (1), that is, a position rotated 30 degrees from the energization pattern (1 ′). And stop. Similarly, (2), (2 '), (3), (3'), (4), (4 '), (5), (5'), (6), (6 '), (1 ) Switch the energization pattern in the order. During this rotation, when the rotation pulse signal as the rotation pulse signal GB of FIG. 9 has changed, upon applying the energization pattern (1 '), the rise of the rotational pulse signal GB is changed from OFF to ON Is detected.

  By the way, in the first example, the same energization pattern for detecting the timing at which the state of the rotation pulse signal G changes from off to on and the energization pattern for actual rotational driving are used. In the second example, the energization pattern shown in FIG. 9 described above is used for detecting the rising timing, and the energization pattern shown in FIG. 10 is used for the actual rotational drive. In the case of FIG. 10 as well, 12 energization patterns (1), (1 ′), (2), (2 ′) to (6), (6 ′) are formed, but energization patterns (1 ′) to (6 ') Differs from that shown in FIG. 9 and is the same pattern as the energization patterns (1) to (6). That is, the waveform shown in FIG. 7 is changed from 6 divisions to 12 divisions.

  When a rising edge of the signal is detected when the energization pattern (1 ′) is applied as described above during the detection operation of the rise timing, the energization pattern two times after the energization pattern (1 ′) in FIG. (2 ′) is stored in the pattern storage unit 79. Further, when the rotation pulse signal G changes like the rotation pulse signal GA of FIG. 9, the energization pattern (2) that is two times after the energization pattern (1) in which the rising timing is detected is stored.

  As described above, in the case of the second example, since the rising timing is detected by rotating the motor rotor 62 by 30 degrees, the positional accuracy of detecting the rising timing of the rotation pulse signal G is improved. For example, in the case of the first example, a rise is detected when the energization pattern (1) is in the range of 0 to 60 degrees in both cases of the rotation pulse signals GA and GB in FIG. However, in the second example, in the case of the rotation pulse signal GA, a rise is detected in the energization pattern (1) in the range of 0 to 30 degrees, and in the case of the rotation pulse signal GB, the range of 30 to 60 degrees. The rising edge is detected in the energization pattern (1 ′).

  If the storing operation of the energization pattern is completed by detecting the rising timing, next, as in the case of the first example, the energization patterns (1), (1 Apply voltage in the order of '), (2), (2'). If the rising timing at which the rotation pulse signal G changes from OFF to ON is detected, the energization pattern (2 ′) stored in the pattern storage unit 79 is in whatever state the energization pattern at that time is. Then, the energization pattern is switched in the order of (3), (3 ′), (4), (4 ′). In this case, the time interval of the energization pattern is gradually shortened every time the pattern is switched to accelerate the rotation speed.

  After that, when the period of the rotation pulse signal G can be measured, the period T1 of the rotation pulse signal G one time before is divided into 12 as shown in FIG. Set as time. Thereafter, every time the rising timing of the rotation pulse signal G is detected, replacement with the energization pattern (2 ′) is performed. In the above description, the rotational drive is performed using the energization pattern shown in FIG. 10 from the start, but the energization pattern of FIG. 9 used when detecting the rising timing may be used. In this case, the energization pattern stored in the pattern storage unit 79 is one of the patterns shown in FIG.

  After the shift to drive control with the energization pattern shown in FIG. 11, if the rotational speed has increased to such an extent that the phase angle θ can be calculated, the phase angle θ is calculated in the same manner as in the first example, and the rotation pulse is calculated. A correct rotational position signal S obtained by delaying the signal G is obtained, and the motor rotor 62 is synchronously driven using the rotational position signal S.

  In the above-described embodiment, the energization pattern is stored in advance by detecting the rise timing of the rotation pulse signal G, and the energization pattern is replaced every time the rise of the rotation pulse signal G is detected during rotation driving. However, the energization pattern may be stored by detecting the fall timing of the signal, which is a change from on to off, instead of the rise of the rotation pulse signal G, and the energization pattern may be replaced each time the fall is detected. . Further, the energization pattern may be replaced both at the rising edge and the falling edge.

  As described above, when the relationship between the rising timing of the rotation pulse signal G and the energization pattern is obtained, the energization pattern is switched slowly so that the motor rotor 62 stops in balance with the magnetic field, and at the rising timing of the rotation pulse signal G. The energization pattern was detected. Such detection of the energization pattern at the time of start-up and storage in the pattern storage unit 79 may be automatically performed by the motor control unit 7 before starting the motor rotation, or may be measured at the shipping stage to be a pattern storage unit. 79 may be stored. The relationship between the rise timing of the rotation pulse signal G and the energization pattern does not change once detected. Therefore, when the motor control unit 7 automatically detects and stores the relationship, the energization pattern is already stored in the pattern storage unit 79 before starting. It is preferable to omit the detection operation when stored.

  In the present embodiment, a two-pole motor has been described as an example. However, the present invention can be similarly applied to motors having other numbers of poles. As a method of obtaining the phase angle θ stored in advance in the phase difference storage unit 76, for example, the angle deviation may be actually measured, or the rotor 4 is rotated by an external driving force (for example, manually rotated). Or the back electromotive force induced in each phase at that time. The obtained phase angle θ is stored in advance in the phase difference storage unit 76 before shipment.

  In the above-described embodiment, the DC brushless motor device mounted on the turbo molecular pump has been described as an example. However, the DC brushless motor device according to the present invention is not limited to the turbo molecular pump, and is a rotary vacuum pump such as a drag vacuum pump. It can be used as a pump rotor driving apparatus.

  In the correspondence between the embodiment described above and the elements of the claims, the sensor target 46 and the rotational position sensor 47 are signal generating means, the phase angle θ is phase difference information, the rotational frequency f is rotational speed information, The signal delay unit 73 and the delay time calculation unit 75 are signal calculation units, the motor drive waveform generation circuit 72 is an energization pattern generation unit, the motor control unit 7 is a motor start control unit, and the phase difference measurement unit 78 is a phase difference calculation unit. Respectively. The above description is merely an example, and when interpreting the invention, there is no limitation or restriction on the correspondence between the items described in the above embodiment and the items described in the claims.

It is a figure which shows one Embodiment of the DC brushless motor apparatus by this invention. 2 is a cross-sectional view showing details of the pump body 1. FIG. It is a figure which shows the relationship between the sensor target 46 and the rotational position sensor 47, (a) shows the case where the rotational position sensor 47 is arrange | positioned in an axial direction, (b) arranges the rotational position sensor 47 in a radial direction. Shows the case. It is a block diagram which shows the structure of DC brushless motor apparatus. It is a figure explaining the energization pattern of a drive voltage. It is a figure explaining the detection operation | movement of phase angle (theta), (a) shows a difference signal, (b) shows the rotation position signal S, (c) shows the rotation pulse signal G. It is a figure which shows the electricity supply pattern of a 1st example. It is a figure which shows an electricity supply pattern in the case of using what divided | segmented the period T1 of the rotation pulse signal G of 1 time before into 6 as an electricity supply pattern switching time. It is a figure which shows the electricity supply pattern for a rise detection in a 2nd example. It is a figure which shows the energization pattern for rotation drives. It is a figure which shows the electricity supply pattern in the case of using what divided | segmented the period T1 of the rotation pulse signal G of 1 time before as electricity supply pattern switching time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Pump main body 2: Power supply device 4: Rotor 6: Motor 7: Motor control part 46: Sensor target 47: Rotation position sensor 61: Motor stator 62: Motor rotor 70: Rotation pulse generation part 72: Motor drive waveform generation circuit 73: Signal delay unit 74: rotational speed detection unit 75: delay time calculation unit 76: phase difference storage unit 77: difference calculation unit 78: phase difference measurement unit 79: pattern storage unit

Claims (5)

A rotation energization pattern, which is a combination pattern of each phase applied voltage of the motor stator, is generated according to a plurality of rotor rotation positions, and each phase applied voltage by the rotation energization pattern is applied to each phase in synchronization with the magnetic pole position. In a DC brushless motor device that applies and rotationally drives the motor rotor ,
Signal generating means for generating a synchronization signal synchronized with the rotation of the motor rotor;
Phase difference storage means for preliminarily storing phase difference information between a rotational position signal representing the magnetic pole position of the motor rotor and the synchronization signal;
Rotational speed detection means for detecting rotational speed information of the motor rotor based on the synchronization signal;
Signal calculating means for calculating the rotational position signal by correcting the synchronization signal obtained during rotation of the motor rotor based on the rotational speed information and the phase difference information stored in the phase difference storage means;
The plurality of rotation energization patterns are generated asynchronously with the rotation of the motor rotor until the motor rotor reaches a predetermined rotation speed, and when the motor rotor reaches a predetermined rotation speed, the plurality of rotation energization patterns are rotated with the rotation of the motor rotor. Energization pattern generation means for rotation generated in synchronization with,
State change detecting means for detecting whether or not the state of the synchronization signal has changed;
Wherein the plurality of rotation energization pattern, the synchronization signal by a predetermined rotational energization pattern a state change associated with the rotor rotational position detected (hereinafter, referred to as the storage pattern) pattern storage means stored When,
Based on the rotation energization pattern generated by the rotation energization pattern generation means, performing asynchronous control for rotationally driving the motor rotor asynchronously with the rotation of the motor rotor until the motor rotor reaches a predetermined rotation speed from a stopped state , Motor start control means for performing synchronous control to rotationally drive the motor rotor in synchronization with the rotational position signal of the motor rotor when the motor rotor exceeds a predetermined rotational speed,
(A) In the asynchronous control, each phase applied voltage corresponding to the plurality of energization patterns for rotation is applied to each phase asynchronously with the rotation of the motor rotor until the motor rotor reaches a predetermined rotational speed from a stopped state. A memory in which the generation order of the plurality of energization patterns for rotation is stored in the pattern storage unit each time the motor rotor is driven to rotate and the state change detection unit detects the state change of the synchronization signal. Controlled to be generated from the pattern,
(B) In the synchronous control, each phase applied voltage corresponding to the rotation energization pattern is repeatedly applied to each phase in synchronization with the rotation of the motor rotor based on the rotational position signal calculated by the signal calculation means. Te, DC brushless motor and wherein the Rukoto the motor rotor is rotated.   The DC brushless motor device according to claim 1,
  Prior to starting the motor, further comprising a preparation processing means for storing the storage pattern in the pattern storage means,
  The preparation processing means includes
  Rotation control means for sequentially applying voltages of the plurality of rotation energization patterns to rotate the motor rotor by a predetermined angle;
When the state change of the synchronization signal is detected by the state change detection unit, the pattern storage unit stores the rotation energization pattern whose generation order is one after the rotation energization pattern at the time of detection as the storage pattern. A DC brushless motor device comprising: a storage control unit;   The DC brushless motor device according to claim 1,
  The plurality of rotation energization patterns each include two N (N is a positive integer) types of rotation energization patterns, and are generated such that the same rotation energization pattern generation sequence is continuous. It consists of 2N rotating energization patterns,
The DC brushless motor device further includes
  Replacing one of the same energizing patterns for rotation in which the generation order is continued with an energizing pattern in an intermediate state in which the energizing patterns for rotation before and after that are alternately repeated, 2N different from the 2N rotating energizing patterns An energization pattern generator for inspection that generates an energization pattern (hereinafter referred to as an energization pattern for inspection);
  Prior to motor start-up, comprising a preparation processing means for storing the storage pattern in the pattern storage means,
  The preparation processing means includes
  Rotation control means for sequentially applying voltages of the 2N test energization patterns to rotate the motor rotor by a predetermined angle;
  When the state change of the synchronization signal is detected by the state change detection unit, the rotation energization pattern having the same generation order as the energization pattern for inspection that is two generations later than the energization pattern for inspection at the time of detection, DC brushless motor apparatus, comprising: storage control means for storing the memory pattern in the pattern storage means. In the DC brushless motor device according to any one of claims 1 to 3 ,
Phase difference calculation means for calculating the phase difference information based on a back electromotive voltage of at least one phase of the motor stator is provided, and the phase difference storage means stores the phase difference information calculated by the phase difference calculation means. DC brushless motor device characterized by the above. A rotary vacuum pump comprising the DC brushless motor device according to any one of claims 1 to 4 as rotational drive means of a pump rotor.

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