JP4676171B2 - Motor drive device and disk device using the same - Google Patents

Description

  The present invention relates to a motor driving device that drives a motor. Furthermore, the present invention relates to a disk device using the same.

2. Description of the Related Art In recent years, devices that drive motors by electronically switching current paths using a plurality of transistors are widely used as motor driving devices used in OA equipment and AV equipment.
In general, in a disk device such as an optical disk device (DVD device, CD device, etc.) or a magnetic disk device (HDD device, FDD device, etc.), a motor is driven by such a driving device.

  Disks used in disk devices tend to have a higher density, and accordingly, high-precision rotation of a disk and a rotor that is attached to the disk and driven to rotate is required.

  Furthermore, from the viewpoint of miniaturization and cost reduction of the device itself, development of motors with a reduced number of position detection elements, which has been indispensable for configuring motors in the prior art, has been actively conducted.

FIG. 15 shows a conventional motor, and its operation will be briefly described. The rotor 10 has a field portion made of a permanent magnet, and one position detection element 41 detects the magnetic field of the field portion of the rotor 10 . That is, the output signal of one position detection element 41 corresponding to the rotation of the rotor 10 is input to the position detector 2030, and the position detector 2030 outputs the output signals H1, H2, H3 that differ from each other by 1/3 period accordingly. Is input to the energization controller 2060. Further, the energization controller 2060 outputs two sets of three-phase voltage signals Kp1, Kp2, Kp3 and Kp4, Kp5, Kp6 according to the input H1, H2, H3. Upper power transistors 2021, 2022, and 2023 are controlled by voltage signals Kp1, Kp2, and Kp3, and lower power transistors 2025, 2026, and 2027 are controlled to be energized by voltage signals Kp4, Kp5, and Kp6. As a result, a three-phase drive voltage is supplied to the coils 11 , 12, and 13 .

  Furthermore, in order to perform stable control over a wide range of rotation, conventional motors are controlled by a single position detection element during low-speed rotation where large rotational changes occur, and position detection during high-speed rotations where only small rotational changes occur. The configuration is such that energization control is performed by detecting a counter electromotive voltage generated in the coil without using the output signal of the element (see, for example, Patent Document 1).

In another conventional motor, since the position of the rotor is detected by one position detection element, the control position may be erroneously detected during a sudden operation of the rotor. The continuous cycle of the output signal of one position detection element is measured, the increase / decrease in the rotational speed of the rotor is detected, and stop control is performed after detecting the reverse rotation of the rotor (for example, refer to Patent Document 2). .
JP 2000-350485 A JP-A-6-223489

  However, the above conventional configuration shows a motor that supplies current to the coil based on the estimated electrical angle from the output of one position detection element. However, the energization control means corresponding to the output of one position detection element has the following problems.

  In Patent Document 1, since only the output of one position detection element can be obtained as rotation information, the rotation speed can be detected but the rotation direction cannot be detected. Therefore, when the reverse torque is generated and the stop operation is performed, the rotor can be stopped once by the reverse torque. However, there is a possibility that the reverse torque is generated and rotated in the reverse direction thereafter.

  As a means for solving these problems, for example, in Patent Document 2, the rotation speed is detected by detecting the increase / decrease of the rotation speed by measuring and comparing the pulse intervals of two or more speed detection pulses according to the rotation during the stop operation. The reverse rotation phenomenon is detected, and when the reverse rotation phenomenon occurs, the supply of current to the coil is stopped, thereby preventing the reverse rotation phenomenon and enabling the stop operation. However, in Patent Document 2, since the brake control is started after actually detecting the reverse rotation phenomenon, the occurrence of the reverse rotation phenomenon cannot be prevented in advance. In addition, since the brake control is performed by stopping the current supply to the coil, the motor rotation after the start of the brake control becomes a free-run state, and it takes a very long time until the motor is completely stopped. Furthermore, since the configuration is such that the increase / decrease of the rotational speed is always detected, even if an erroneous speed detection pulse is measured and compared, the current is supplied to the coil at a rotational speed at which the rotational state cannot actually be reversed. There is a risk that a problem will occur that will stop the operation.

  A disk device that reproduces DVD-ROM, CD-ROM, CD disk, etc., requires a rotating operation in a wide speed range from high-speed reproduction at 10,000 rpm to CD reproduction at 200 rpm, and stably rotates in these rotational speed ranges. There is a demand for driving. In addition, in a rewritable disk device such as a DVD-RAM / RW device, information recording / reproduction is performed on a high-density disk, and therefore it is necessary to rotate the disk with high accuracy in recording and reproduction on the disk. In addition to optical disk devices, magnetic disk devices such as HDDs and FDDs are required to be manufactured at low cost and to realize stable disk rotation drive.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a motor drive device capable of smoothly and quickly stopping the rotation of a rotor at a low manufacturing cost and a disk device that realizes a stable recording / reproducing operation. It is in.

  A motor driving device according to the present invention is a device that drives a motor having a rotor having a field portion that generates a field magnetic flux and a plurality of coils. The motor drive device includes power supply means for supplying a DC voltage, power supply means, control means, frequency comparison means, rotation state command means, and brake switching means.

The power supply means includes a plurality of switching elements, converts the DC voltage from the power supply means into a desired AC voltage, and supplies driving power to the motor. The position detection means detects the rotational position of the rotor of the motor and outputs a single position signal. The control means controls the switching operation of the switching element of the power supply means using the position signal. The frequency comparison means is a period from the start of the brake control of the motor until the motor speed reaches zero, and the frequency of the position signal is equal to or higher than a predetermined value , and the frequency of at least two consecutive sections in the single position signal. Are detected , a frequency reversal state is detected in which the frequency of the signal in the section output later is higher than the frequency of the signal in the section output earlier, and a detection signal indicating the detection result is output. The rotation state command means outputs a command signal for exciting and controlling the coil so as to give a positive torque or a reverse torque to the rotor. The brake switching means is either a reverse torque brake control that applies a reverse torque to the rotor to brake the rotation of the rotor as a brake control of the motor, or a short brake control that shorts the motor coil to brake the rotation of the rotor. And instruct the control means. The brake switching means selects reverse torque brake control when the detection signal from the frequency comparison means does not indicate a frequency reverse state while the rotation state command means outputs a command signal for applying reverse torque. When the detection signal indicates the frequency reverse state, the short brake control is selected and the control means is instructed.

  In the motor drive device, the frequency comparison means includes a reference clock signal generation circuit that outputs a reference clock signal, a counter circuit that measures the reference clock signal within a period corresponding to the position signal, and a latch that latches the output of the counter circuit. 1 latch circuit, a delay circuit that delays the position signal by one cycle, a second latch circuit that latches the output of the counter circuit in synchronization with the output of the delay circuit, an output signal of the first latch circuit, and a second latch circuit A comparison / determination circuit that compares the output signal to detect a reverse rotation state and outputs a detection signal may be included.

  The frequency comparison means performs the reverse rotation detection operation only when the command signal for giving the reverse torque is output by the rotation state command means and the frequency of the position signal is lower than the predetermined value. You may make it perform.

  In the motor drive device, the brake switching means detects the position signal of the next section from the time when the time corresponding to the previously output section has elapsed with the end point of the previously output section as the base point. In the meantime, the short brake control may be selected.

  The position detection means may include a position detection element that detects a magnetic flux in the field portion of the rotor and creates a position signal.

  A disk device according to the present invention is a motor driving device that drives a recording medium to rotate, a motor driving device described above, a head unit that performs at least one of signal reproduction and signal recording on the recording medium, and a head unit that reproduces the recording medium. Information processing means for performing at least one of processing of the reproduced signal and signal processing of the recorded information recorded on the recording medium by the head means.

  According to the motor drive device of the present invention, by comparing the continuous rotation frequency according to the motor rotation, the timing of shifting from the deceleration of the motor to the acceleration during the motor braking is detected, and after that timing, the reverse brake is applied. Since switching to the short brake, the rotation of the motor can be stopped smoothly and quickly. As a result, it is possible to realize a disk device and a motor driving device that perform highly reliable rotational driving with a simple configuration.

  Embodiments of a motor drive device and a disk device according to the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a motor drive device according to a first embodiment of the present invention.
A motor 100 driven by a motor driving device includes a rotor 10, a stator provided with three-phase coils 11, 12, and 13, and a position detection element 41 provided on the stator. The rotor 10 is attached with a field portion that generates a multi-pole field magnetic flux by a magnet magnetic flux. Here, it is assumed that a field portion by a two-pole permanent magnet magnetic flux is attached. However, in general, multipole field parts such as four poles, six poles, etc. can be configured.

  The three-phase coils 11, 12, and 13 are electrically shifted by 120 degrees with respect to the relative relationship with the rotor 10 in the stator. Here, the electrical angle of 360 degrees corresponds to a pair of angular widths of the N pole and the S pole of the field portion of the rotor. One end of each of the coils 11, 12, 13 is commonly connected, and the other end is connected to the output terminal side of the power supplier 20 as a power supply terminal.

  The three-phase coils 11, 12, 13 generate a three-phase magnetic flux by the three-phase drive currents I 1, I 2, I 3, generate a drive force by interaction with the field part of the rotor 10, and drive the rotor 10 with the drive force give.

  The position detection element 41 is, for example, a Hall element that is a magnetoelectric conversion element, detects the magnetic pole magnetic flux in the field portion of the rotor 10, and a position detection signal H 1 whose amplitude changes smoothly according to the rotational position of the rotor 10. Is output.

  The motor driving device includes a power supply device 20, a position detector 30, a command device 40, a switching operation device 50, an energization controller 60, a rotation state command device 70, a frequency comparator 71, and a brake switch 72. With.

  The position detector 30 receives a single position detection signal H1 output from the position detection element 41, and outputs a single position signal FG subjected to waveform processing as a digital value.

  The commander 40 detects the rotational speed of the rotor 10 based on the position signal FG of the position detector 30 and generates a command signal Ac corresponding to the difference between the rotational speed of the rotor 10 and the target speed. Here, the command signal Ac of the command device 40 is a voltage signal corresponding to the position signal FG.

  The three-phase first energization control signals N1, N2, and N3 and the three-phase second energization control signals M1, M2, and M3 of the energization controller 60 are supplied to the power supply unit 20. The power supply unit 20 includes three power amplifiers 21 to 23 on the high voltage side, three power amplifiers 25 to 27 on the low voltage side, and six diodes 21d to 23d and 25d to 27d, and the current path to the coils 12, 13, and 14 is switched as the rotor 10 rotates.

  In the power supplier 20, the power amplifiers 21 to 23 are in response to the first energization control signals N1, N2, and N3, and the power amplifiers 25 to 27 are in response to the first energization control signals M1, M2, and M3. Each performs high-frequency switching operation. Thereby, the DC voltage from the DC power source 5 is converted into a desired AC voltage, and the motor 100 is driven.

  The switching actuator 50 includes a current detector 51 and a switching controller 52. The current detector 51 is a conduction current I1, I2, I3 or a combined supply current supplied from the DC power supply 5 to the three-phase coils 11, 12, 13 via the power amplifiers 21, 22, 23 in the power supply 20 Ig is detected, and a current detection signal Ad corresponding to the detected current value is output. The switching controller 52 outputs a high-frequency switching pulse signal Wp corresponding to the comparison result between the current detection signal Ad and the command signal Ac from the command device 40. The switching pulse signal Wp is usually a high-frequency signal in the range of 20 kHz to 500 kHz. As a result, the combined supply current Ig is current-controlled according to the command signal Ac. As a result, the drive currents I1, I2, and I3 to the three-phase coils 12, 13, and 14 can be accurately controlled according to the command signal Ac, and the pulsation of the generated drive force can be reduced. That is, the vibration and noise of the rotor 10 can be greatly reduced.

  The rotation state command device 70 outputs a rotation direction command signal DR that determines the rotation direction of the rotor 10.

  The frequency comparator 71 compares the frequency of at least two consecutive sections in the position signal FG output from the position detector 30, and the frequency of the signal of the section output later is compared with the frequency of the signal of the section output first. The “reversed state” is detected. Specifically, the frequency comparator 71 receives the position signal FG output from the position detector 30 and the rotation direction command signal DR output from the rotation state command unit 70. The frequency comparator 71 activates the frequency comparison signal Fs when the rotation direction command signal DR is a reverse rotation command and the frequency of the subsequent signal is higher than the previous signal in time in the continuous position signal FG. And output to the brake switch 72. In other cases, the frequency comparator 71 deactivates the frequency comparison signal Fs.

  The brake switch 72 outputs a brake switch signal Bc for switching the brake mode to the energization controller 60 in accordance with the frequency comparison signal Fs obtained from the frequency comparator 71. Here, a specific operation will be described with reference to the timing chart of FIG.

  FIG. 2 shows an operation when a reverse rotation command based on the rotation direction command signal DR is output from a state where the rotor 10 rotates in the forward direction at a predetermined frequency. Referring to FIG. 2A, in order to stop the motor 100 from the rotation state command device 70, when a reverse rotation command is output (DR signal becomes “High”), the energization controller 60 sends the rotor 10 to the rotor 10. In accordance with the position signal FG output from the position detector 30, the switching elements 21 to 23 and 25 to 27 of the power supply device 20 are driven to switch the current paths of the coils 11, 12, and 13 so as to apply reverse torque. . Hereinafter, such brake control in which reverse torque is applied to the rotor to perform braking is referred to as “reverse torque brake control”. As a result, the rotational speed of the rotor 10 gradually decreases. At this time, the frequency of the position signal FG that normally changes in accordance with the rotation of the rotor 10 gradually decreases.

  However, when the inertia of the rotor 10 is extremely small with respect to the torque that can be generated in the rotor 10 by the power supply device 20, as shown in FIG. 2B, the previous signal A (having a cycle T1). After that, a later signal B having a period T2 smaller than the period T1 may appear. In other words, a reverse phenomenon may occur in which the time (frequency) magnitude relationship is reversed. This is because the output signal of the energization controller 60 that switches the current path between the power supply unit 20 and the coils 11, 12, and 13 is based on the signal one cycle before the position signal FG output from the position detector 30. It can occur because it is generated. When the inertia of the rotor 10 is as described above, an excessive reverse torque is applied, and the rotation of the rotor 10 also changes rapidly accordingly. At that time, a large deviation occurs between the actual position signal FG and the signal used for the energization controller 60 one cycle before, and in the worst case, a torque opposite to the rotation direction of the reverse rotation command is generated. This will cause a malfunction in operation.

  In view of this, the present invention solves this problem and performs the following control in order to make it possible to stop the rotation of the rotor smoothly and quickly compared to the conventional method.

  That is, when the motor is brake controlled, the frequency comparator 71 compares the frequency of two consecutive sections in the position signal FG output from the position detector 30, and the frequency of the subsequent section is compared with the preceding section. That is, a state where the frequency becomes higher than the above-mentioned frequency, that is, a “reverse state” is detected. When this reverse rotation state is detected, the brake switch 72 applies a brake (short brake) to the motor 100 by short-circuiting the coils 11, 12, 13 from the “reverse torque brake control”. Switch to "Short brake control". This will be described in further detail below.

  The frequency comparator 71 measures the frequency (for example, only the rising edge) of the position signal FG output from the position detector 30, and a time T1 ′ equal to the period T1 of the previous signal A is based on the position signal FG. If a later signal B is detected before the time elapses, it is determined that a reverse state has occurred, and the frequency comparison signal Fs is changed from inactive (second state) to active (first state) at the time of detection. 72 (see FIG. 2D). When receiving the frequency comparison signal Fs indicating the reverse rotation state, the brake switch 72 makes the brake switch signal Bc active (“High”) and outputs it to the energization controller 60.

  When the energization controller 60 receives the active brake switching signal Bc, the energization controller 60 outputs a control signal to the power supplier 20 so that the coils 11, 12, and 13 are short-circuited by the power supplier 20. By short-circuiting the coils 11, 12 and 13, the motor 100 is braked (short brake) (see FIG. 2E).

  As described above, in this embodiment, when a large shift (reverse rotation) occurs in the position signal FG used in the current position signal FG and the energization controller 60 in the previous cycle, the reverse rotation torque brake is performed. Since the control is immediately switched from the short brake control to the short brake control, it is possible to realize a motor that can stop the rotation of the rotor 10 more smoothly and more quickly than the conventional method while preventing a problem when the inertia is light.

The frequency comparator 71 preferably performs the reverse rotation detection operation based on the position signal FG during the period from when the motor brake control is started until the motor speed reaches zero (the same applies to the following embodiments). ). For example, the reverse rotation state detection operation may be performed based on the position signal FG during a period in which the rotation frequency of the rotor 10 is not less than a predetermined value (ω _th0 ) that is not zero. In this case, the motor brake control operation is in progress and the state where the motor has shifted from deceleration to acceleration is detected before the motor stops, and the short brake control can be started before the reverse rotation of the motor occurs. There is an advantage that the reverse rotation operation of the motor can be prevented in advance.

(Embodiment 2)
Hereinafter, a second embodiment of the motor drive device according to the present invention will be described.
The basic configuration of the present embodiment is the same as that of the first embodiment, and further embodies the internal configuration of the frequency comparator. FIG. 3 is a diagram showing the configuration of the embodied frequency comparator 71A.

  The frequency comparator 71A includes a reference clock generation circuit 78 that outputs a reference clock signal CLK, and a first counter circuit 73 that counts the position signal FG based on the reference clock signal CLK and outputs a value corresponding to the rotational frequency of the rotor. A first latch circuit 74 that latches the output of the first counter circuit in synchronization with the position signal FG, a delay circuit 77 that delays the position signal FG by one period, and a first counter in synchronization with the output of the delay circuit. A second latch circuit 75 that latches the output of the circuit 73 and a comparison / determination circuit 76 that can compare the output of the first latch circuit and the output of the second latch circuit are included.

  The position signal FG from the position detector 30 and the rotation command signal DR from the rotation state command unit 70 are input to the frequency comparator 71A. The input position signal FG is input to the first counter circuit 73 and the delay circuit 77, and the reference clock signal CLK output from the reference clock generation circuit 78 is input to the first counter circuit 73. Next, the first counter circuit 73 counts the frequency of the input position signal FG based on the reference clock signal CLK, and the count value is input to the first latch circuit 74 and the second latch circuit 75, respectively. The first latch circuit 74 latches and outputs the count value in synchronization with the position signal FG, and the second latch circuit 75 latches and outputs the output of the first counter circuit 73 in synchronization with the output of the delay circuit 77. The output values of the first latch circuit 74 and the second latch circuit 75 are input to the comparison determination circuit 76. The comparison / determination circuit 76 has a smaller output value of the second latch circuit 75 than that of the first latch circuit 74 (that is, the frequency of the current cycle is higher than the frequency of the previous cycle), and the rotation command signal. When DR is a reverse rotation command signal, the frequency comparison signal Fs is made active (reverse rotation state) and output.

  In this way, the frequency comparator 71A performs frequency comparison of the position signal FG in the continuous section output from the position detector 30, and the rotor 10 is in a state different from the rotation command signal DR output from the rotation state command unit 70. (That is, when the rotor 10 accelerates when the rotation command signal DR is the reverse rotation command signal), the frequency comparison signal Fs indicating the reverse rotation state is immediately output, and the reverse rotation torque is generated to perform braking. Since the reverse torque brake control is switched to the short brake control in which the coils 11, 12 and 13 are short-circuited and braked, it is possible to realize a motor that stops the rotation of the rotor 10 more smoothly and quickly than in the conventional method. Furthermore, since the frequency comparator 71A is entirely composed of logic circuits, a very low-cost motor driving device can be realized.

(Embodiment 3)
Hereinafter, a third embodiment of the motor driving apparatus according to the present invention will be described.
The basic configuration of the motor drive device in the present embodiment is the same as that of the first embodiment, and the frequency comparator is different from that of the second embodiment (FIG. 3). FIG. 4 shows the configuration of the frequency comparator 71B of this embodiment.

The frequency comparator 71B of the present embodiment performs an operation for detecting the reverse rotation state by comparing the frequencies only when the rotational frequency of the rotor 10 is not more than a predetermined value (ω _th1 ). That is, when the rotational frequency of the rotor 10 is higher than the predetermined value (ω _th1 ), the frequency comparator 71B always outputs the inactive frequency comparison signal Fs. The predetermined value (ω _th1 ) is set so as to satisfy the relationship of ω _th1 > ω _th0 when the predetermined value (ω _th0 ) is set.

  In FIG. 4, the frequency comparator 71B counts the position signal FG based on the reference clock signal CLK, and outputs a value corresponding to the rotational frequency of the rotor 10, and the first counter circuit 73 A first latch circuit 74 that latches the output in synchronization with the position signal FG, a delay circuit 77 that delays the position signal FG by one cycle, and an output from the first counter circuit 73 that synchronizes with the output of the delay circuit 77 The second latch circuit 75 receives and latches at least one output signal from the first counter circuit 73, a comparison / determination circuit 76B that can compare the output of the first latch circuit 74 and the output of the second latch circuit 75. And a third latch circuit 79.

  Since the operations other than the third latch circuit 79 and the comparison / determination circuit 76B are the same as those in the second embodiment, they are omitted here.

The count value of the first counter circuit 73 is represented by a plurality of bits. At least one output signal (1 bit) of the first counter circuit 73 corresponding to a predetermined rotation frequency (ω _th1 ) of the rotor 10 among the plurality of bits is input to the third latch circuit 79. Based on the input signal, the third latch circuit 79 outputs a signal indicating that when the rotational frequency of the rotor 10 is equal to or less than a predetermined value (ω _th1 ).

The output signal of the third latch circuit 79 is input to the comparison determination circuit 76B. Only when the output signal of the third latch circuit 79 indicates that the rotational frequency of the rotor 10 is equal to or less than a predetermined value (ω _th1 ), the comparison determination circuit 76B and the output signal of the first latch circuit 74 An operation of detecting a reverse state is performed by comparing the output signals of the latch circuit 75. When the output signal of the third latch circuit 79 does not indicate that “the rotational frequency of the rotor 10 is equal to or lower than the predetermined value (ω _th1 )”, the comparison determination circuit 76B always deactivates the position signal Fs.

As described above, in the present embodiment, when the rotational speed of the rotor is equal to or less than the predetermined value (ω _th1 ), frequency comparison is performed, and switching from reverse torque brake control to short brake control is performed based on the result. And enters an operation mode (short brake control mode) in which short brake control is performed when a reverse rotation state is detected (see FIG. 5).

That is, since the frequency comparator 71B detects the reverse rotation state only when the rotor 10 is below the predetermined rotation frequency, the reverse rotation is detected in the position signal FG when the rotor 10 is rotating at the predetermined rotation speed or higher. Even if a state has occurred, it is not detected, so that the reverse torque brake control is not switched to the short brake control. Thereby, it is possible to prevent a malfunction of the brake switching control in a state where the rotor 10 is rotating at a high speed equal to or higher than a predetermined rotation speed (ω _th1 ), and a more reliable operation can be realized.

(Embodiment 4)
Hereinafter, a fourth embodiment of the motor drive device according to the present invention will be described.
The basic configuration of the motor drive device of the present embodiment is the same as that of the first embodiment, and a further configuration is adopted as the internal configuration of the frequency comparator. FIG. 6 shows the configuration of the frequency comparator 71C of this embodiment.

  The frequency comparator 71C of the present embodiment is a case where the relationship between the frequency of the signal in the previous section and the frequency of the signal in the subsequent section in two consecutive sections of the position signal FG is not reversed under brake control. Even if it exists, when the fluctuation range is larger than the predetermined value, the frequency comparison signal Fs is made active as in the case of detecting the reverse rotation state. Thereby, the brake control is switched from the reverse torque brake control to the short brake control. The reason for controlling in this way is that if the rotational frequency changes abruptly (decelerates) during braking, it is highly possible that the rotational frequency will be reversed or accelerated immediately thereafter. In order to achieve a smooth and quick stop of the rotor.

  In FIG. 6, the frequency comparator 71C includes a first counter circuit 73 that counts the position signal FG based on the reference clock signal CLK, and a first latch that latches the output of the first counter circuit 73 in synchronization with the position signal FG. A latch circuit 74; a delay circuit 77 that delays the position signal FG by one cycle; a second latch circuit 75 that latches the output of the first count circuit 73 in synchronization with the output of the delay circuit 77; And a comparison / determination circuit 76 </ b> C capable of comparing the output with the output of the second latch circuit 75.

  Since the operations other than the comparison determination circuit 76C are the same as those in the second embodiment, they are omitted here.

  The comparison determination circuit 76C receives the output values of the first latch circuit 74 and the second latch circuit 75, and the output value of the first latch circuit 74 is (3/2) times larger than the value of the second latch circuit 75. When the output value is smaller, the frequency comparison signal Fs is activated.

A specific operation of the comparison determination circuit 76C will be described with reference to the timing chart of FIG.
The comparison determination circuit 76C indicates that the output signal DR of the rotation state command device 70 indicates the reverse rotation command state and is 3/2 times the period T1 of the previous signal A from the time when the previous signal A ends. Even if the time corresponding to (a predetermined number of times) has elapsed, if the subsequent signal B (having the cycle T2) does not end, the output signal Fs is made active. That is, when the frequency of the subsequent signal B is smaller than a value obtained by multiplying the frequency of the previous signal A by 2/3, the output signal Fs becomes active. As a result, the brake switch 72 (see FIG. 1) outputs a brake switch signal Bc to the energization controller 60 and switches from reverse torque brake control to short brake control. In the present embodiment, the brake control is switched when the frequency of the subsequent signal B is 2/3 times the frequency of the previous signal A, but it is possible to determine that sudden fluctuation (deceleration) has occurred. If so, the brake control may be switched when the subsequent signal B satisfies another relationship with respect to the previous signal A.

  In this way, during the braking by the reverse torque brake control, by detecting a rapid decrease in the rotation frequency, the rotor 10 behaves differently from the operation according to the rotation command signal DR output from the rotation state command device 70 (for example, Since the reverse brake control is switched to the short brake control before reaching the deceleration command, the motor drive device that stops the rotation of the rotor 10 more smoothly and quickly than the conventional method can be realized.

(Embodiment 5)
FIG. 8 shows the configuration of the fifth embodiment of the motor driving apparatus according to the present invention. The configuration and operation of the motor drive device of the present embodiment are basically the same as those of the first embodiment except for the brake switch 72A.

  The brake switching device 72A of the present embodiment inputs the position signal FG output from the position detector 30 and the frequency comparison signal Fs output from the frequency comparator 71, and each of the position signal FG and the frequency comparison signal Fs. Based on this, the brake switching signal Bc is output.

  A specific operation of the brake switching unit 72A will be described with reference to the timing chart of FIG. When the output signal Fs of the frequency comparator 71 is inactive (a state where the reverse rotation state is not detected), the brake switch 72A is as follows in each cycle of the signal FG as shown in FIG. 9 (e). Operate.

  Here, description will be made by paying attention to the latter signal B of the two signals A and B that are continuous in each cycle of the signal FG. When the output signal Fs of the frequency comparator 71 is inactive, the brake switching device 72A, after the lapse of time T1 ′ equal to the cycle T1 of the signal A from the end time of the previous signal A, The brake switching signal Bc is made active (“High”) only during the time difference (T2−T1) between T1) and the period (T2) of the subsequent signal B (see FIG. 9E). Thereafter, when the output signal Fs of the frequency comparator 71 becomes active (when a reverse rotation state is detected), the brake switching device 72A activates the brake switching signal Bc from that point in order to instruct short brake control. (See FIG. 9 (d)).

  In this way, in the position signal FG, the short brake control is performed only during the period of the difference between the previous signal A and the subsequent signal B within the section of the subsequent signal B, so that the rotor 10 differs from the actual position. Therefore, it is possible to realize a motor drive device that stops the rotation of the rotor 10 smoothly and quickly.

(Embodiment 6)
FIG. 10 shows a sixth embodiment of the motor driving apparatus according to the present invention. The configuration and operation of the motor drive device of the present embodiment are basically the same as those of the first embodiment, except that a position signal adder is provided.

  In FIG. 10, a position signal adder 80 receives a position signal FG output from the position detector 30 and adds a signal having a period obtained by adding a predetermined time to the period of the input position signal FG to an added position signal FG_I +. Output as. The energization controller 60 controls the switching operation of the power amplifiers 21 to 23 and 25 to 27 based on the addition position signal FG_I +.

  A specific operation of the motor drive device of this embodiment will be described with reference to the timing chart of FIG. FIG. 11B shows the position signal FG, and FIG. 11F shows the position generated based on the position signal of the previous cycle when the position signal of the previous cycle is used in the energization controller. It is the figure which showed signal FG_I. FIG. 11G shows the output of the position signal adder 80, and is a diagram showing a signal FG_I + obtained by adding a predetermined time (T0) to the position signal one cycle before.

  When the output signal DR of the rotation state command device 70 indicates a reverse rotation command (see FIG. 11A), an added position signal FG_I + (FIG. 11 (FIG. 11 ()) obtained by adding a predetermined time T0 to the position signal FG output from the position detector 30. The period of g)) is the energization period used by the energization controller 60.

  As described above, since the addition position signal FG_I + obtained by adding the predetermined time T0 is used as a signal used in the energization controller 60, as compared with the case where the position signal one cycle before the normal is used (see FIG. 11 (f)). The deviation between the energization cycle used in the energization controller 60 and the actual rotation cycle of the rotor 10 is reduced. That is, as shown in FIG. 11, since the shift TD between the cycle T1 ′ in the signal FG and the cycle T2 in the signal FG_I is corrected at a predetermined time T0, the actual rotation cycle of the rotor 10 is more accurately reflected. Thus, a more accurate control energization cycle can be provided. Here, the predetermined time T0 is preferably set to about ½ or less of the time corresponding to the period T1 to which the predetermined time T0 is added. The predetermined time T0 may be determined according to the period T1 to which the predetermined time T0 is added. For example, the predetermined time T0 may be a value obtained by multiplying the period T1 to which the predetermined time T0 is added by a predetermined ratio (α%). With the above configuration, it is possible to realize a motor drive device that smoothly and quickly stops the rotation of the rotor 10.

(Embodiment 7)
Hereinafter, a seventh embodiment of the motor driving apparatus according to the present invention will be described.
The basic configuration of the motor drive device of the present embodiment is the same as that of the first embodiment, and another configuration is adopted as the internal configuration of the frequency comparator. FIG. 12 shows the configuration of the frequency comparator 71D.

When a reverse torque brake is applied to the rotor 10 to decelerate, the rotational speed of the rotor 10 once becomes zero as shown in FIG. Such a phenomenon may cause erroneous detection of the rotation state of the rotor 10 and may cause malfunction of the motor. Therefore, in the present embodiment, as shown in FIG. 13B, a predetermined rotational frequency (ω _th2 ) indicating a low-speed value close to the stop state is set, and the rotational frequency of the rotor 10 is set from the predetermined value (ω _th2 ). By applying a short brake when the vehicle becomes smaller, such erroneous detection and malfunction are prevented. This control is effective when the reverse rotation state is not detected and the reverse torque brake control is not switched to the short brake control even when the rotation speed is close to the stop state during the brake control.

  In FIG. 12, the frequency comparator 71D includes a first counter circuit 73 that counts the position signal FG based on the reference clock signal CLK, and a first latch that latches the output of the first counter circuit 73 in synchronization with the position signal FG. A latch circuit 74; a delay circuit 77 that delays the position signal FG by one period; a second latch circuit 75 that latches the output of the first counter circuit 73 in synchronization with the output of the delay circuit 77; A comparison / determination circuit 76D that can compare the output with the output of the second latch circuit 75 and a fourth latch circuit 79D that receives and latches at least one output signal of the first counter circuit 74 are configured.

  Since the operations other than the fourth latch circuit 79D and the comparison / determination circuit 76D are the same as those in the second embodiment, they are omitted here.

The count value of the first counter circuit 73 is represented by a plurality of bits. At least one output signal (1 bit) of the first counter circuit 73 corresponding to a predetermined rotation frequency (ω _th2 ) of the rotor 10 among the plurality of bits is input to the fourth latch circuit 79D. Here, the predetermined rotation frequency (ω _th2 ) is set to a low value near the stop of the rotor 10.

The fourth latch circuit 79D activates the output signal Fs when the rotational frequency of the rotor 10 is equal to or lower than the predetermined rotational frequency (ω _th2 ), and when the rotor 10 is higher than the predetermined rotational frequency (ω _th2 ). The output signal of the fourth latch circuit 79D is made inactive.

The output signal of the fourth latch circuit 79D is input to the comparison determination circuit 76D. The comparison determination circuit 76D outputs the output of the first latch circuit 74 when the output signal Fs of the fourth latch circuit 79D is inactive, that is, when the rotation frequency of the rotor 10 is higher than a predetermined rotation frequency (ω _th2 ). The signal is compared with the output signal of the second latch circuit 75, and the comparison result is output as the frequency comparison signal Fs. In this case, switching between reverse torque control and short brake control is performed based on the frequency comparison signal Fs.

On the other hand, when the output signal of the fourth latch circuit 79D is active, that is, when the rotational frequency of the rotor 10 is equal to or lower than the predetermined rotational frequency (ω _th2 ), the comparison determination circuit 76D does not perform frequency comparison, The comparison signal Fs is forcibly activated and output. That is, when the rotor 10 has a predetermined rotation frequency (ω _th2 ) or less, the comparison result of the output signal of the first latch circuit 74 and the output signal of the second latch circuit 75 is not related, that is, the rotation of the rotor 10. Regardless of the state, an active frequency comparison signal Fs is output from the frequency comparator 76D. When the brake switch 72 receives this frequency comparison signal Fs, the brake switch 72 activates the brake switch signal Bc, whereby braking by short brake control is performed.

  As described above, by erroneously detecting the short brake control by forcibly activating the frequency comparison signal Fs near the stop of the rotor 10 (near the rotation frequency zero), erroneous detection of the rotation state when the rotor 10 starts reverse rotation after stopping. Thus, a more reliable braking operation can be realized.

(Embodiment 8)
FIG. 14 shows the configuration of a disk device according to the present invention.
The disk apparatus shown in FIG. 14 includes the motor driving apparatus described in the above embodiment, the motor 100, a head 2 that records and reproduces information on the disk 1, and an information processing unit 3.

  The disk 1 is a recording medium such as a hard disk or an optical disk on which information signals are recorded and reproduced, and is supported by a motor 100 for rotation. Digital information signals (for example, high-quality audio / video signals) are recorded on the disc 1. The head 2 is constituted by an optical head or a magnetic head, and reproduces a signal from the disk 1 or records a signal on the disk 1. The information processing unit 3 processes the signal read by the head 2 and outputs it as a reproduction signal (for example, a high-quality audio / video signal) or generates a recording signal for the disk 1 via the head 2. Perform predetermined processing.

  Since the disk 1 is fixedly attached to the rotor 10 and directly rotated by the rotor 10, the rotation state of the disk 1 depends on the rotation state of the rotor 10. According to the motor according to the above-described embodiment, since the rotor 10 can perform a reliable and stable rotation, the disk 1 supported and supported by the rotor 10 also has a high-accuracy rotational drive and speed. Control can be implemented. As a result, a highly reliable and low-cost disk device can be provided.

  The various embodiments of the motor drive device according to the present invention have been described above. The motor drive device according to the present invention is suitable for a disk device, for example, and its application can be widely used as a device for rotational drive of OA / AV equipment and the like. Furthermore, in general, it can be widely used as a motor drive device for speed control.

  In the above-described embodiment, only one position detection element 41 is provided, and the position detector 30 inputs a single position detection signal H1 output from the position detection element 41 and performs waveform processing as a digital value. However, two or three position detecting elements 41 may be provided. In that case, at least one position signal is output from the position detector 30. By providing two or three position detecting elements 41, the controllability is improved as compared with the case where only one position detecting element 41 is provided, and more than or equal to the case where only one position detecting element 41 is provided. An effect can be obtained. Alternatively, the position detection element may not be used. In this case, the position detector 30 obtains the position signal from the position detection element by outputting the position signal using the voltage induced in the coils 11, 12, and 13 as the position detection signal when the rotor 10 rotates. The same effect as the case can be obtained.

  Note that various modifications can be made to the specific configuration of the above-described embodiment. For example, the coils 11, 12, and 13 of each phase of the motor 100 may be configured by connecting a plurality of partial coils in series or in parallel. The three-phase coil is not limited to the star connection but may be a delta connection. Further, the number of phases of the coil is not limited to three phases. The present invention can also be applied to a configuration having a plurality of phase coils. Further, the number of magnetic poles in the field portion of the rotor 10 is not limited to two but may be four or more.

  The power transistors 21 to 23 and 25 to 27 of the power supplier 20 include various types such as an NPN bipolar transistor, a PNP bipolar transistor, an N channel field effect transistor, a P channel field effect transistor, and an IGBT transistor. The transistor can be used. By performing high-frequency switching operation of the power transistor, power loss and heat generation of the power transistor can be reduced, and an integrated circuit can be easily formed.

  In addition, various modifications can be made without changing the gist of the present invention, and it goes without saying that these are included in the present invention.

  The motor drive device of the present invention is a motor drive device that can stop the rotation of the rotor smoothly and quickly at a low manufacturing cost, and can be widely used as a device for rotational drive of OA / AV equipment, for example. It is suitable for a disk device for recording / reproducing information on / from a rotating disk. The motor driving device of the present invention can be widely used as a motor driving device that performs general speed control.

It is a block diagram of the motor drive device of Embodiment 1 by this invention. It is a timing chart in the motor drive device of Embodiment 1 by this invention. It is a block diagram of the frequency comparator in the motor drive device of Embodiment 2 by this invention. It is a block diagram of the frequency comparator in the motor drive device of Embodiment 3 by this invention. It is a figure explaining switching to the short brake control mode of the motor drive device of Embodiment 3. FIG. It is a block diagram of the frequency comparator in the motor drive device of Embodiment 4 by this invention. 10 is a timing chart in the frequency comparator according to the fourth embodiment. It is a block diagram of the motor drive device of Embodiment 5 by this invention. 10 is a timing chart in the motor drive device of the fifth embodiment. It is a block diagram of the motor drive device of Embodiment 6 by this invention. 10 is a timing chart in the motor drive device of the sixth embodiment. It is a block diagram of the frequency comparator in the motor drive device of Embodiment 7 by this invention. (A) It is the figure which showed the change of the rotor rotation speed at the time of continuing reverse torque brake. (B) It is the figure which showed the change of the rotor rotational speed by the brake control of the motor drive device of Embodiment 7. FIG. FIG. 11 is a configuration diagram of a disk device according to the present invention (Embodiment 8). It is a block diagram of the conventional motor drive device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Disc 2 Head 3 Information processing part 5 DC power supply 10 Rotor 11, 12, 13 Coil 20 Power supply device 30 Position detector 40 Command device 41 Position detection element 50 Switching operation device 60 Energization controller 70 Rotation state command device 71, 71A , 71B, 71C, 71D Frequency comparator 72, 72A Brake switch 80 Position signal adder 100 Motor

Claims (6)

An apparatus for driving a motor having a rotor having a field part for generating a field magnetic flux and a coil having a plurality of phases,
Power supply means for supplying a DC voltage;
A power supply means that includes a plurality of switching elements, converts a DC voltage from the power supply means into a desired AC voltage, and supplies driving power to the motor;
Position detecting means for detecting the rotational position of the rotor of the motor and outputting a single position signal;
Control means for controlling the switching operation of the switching element of the power supply means using the position signal;
Compare the frequency of at least two consecutive sections in the single position signal during the period from the start of the brake control of the motor until the motor speed reaches zero and the frequency of the position signal is a predetermined value or more. Thus, the frequency comparison means for detecting a frequency reversal state in which the frequency of the signal of the section output later is higher than the frequency of the signal of the section output earlier, and outputting a detection signal indicating the detection result;
A rotation state command means for outputting a command signal for exciting and controlling the coil so as to apply a positive torque or a reverse torque to the rotor;
As the brake control of the motor, one of reverse torque brake control that applies reverse torque to the rotor to brake the rotation of the rotor and short brake control that short-circuits the motor coil to brake the rotation of the rotor is selected. And brake switching means for instructing the control means,
The brake switching means outputs a reverse torque when the detection signal from the frequency comparison means does not indicate the frequency reverse rotation state while the rotation state command means outputs a command signal for giving a reverse torque. A motor drive device characterized by selecting brake control, and selecting short brake control and instructing the control means when the detection signal indicates the frequency reverse state. The frequency comparison means includes a reference clock signal generation circuit that outputs a reference clock signal, a counter circuit that measures the reference clock signal within a period corresponding to the position signal, and a first latch that latches the output of the counter circuit A circuit, a delay circuit that delays the position signal by one cycle, a second latch circuit that latches an output of the counter circuit in synchronization with an output of the delay circuit, an output signal of the first latch circuit, and the second 2. The motor driving apparatus according to claim 1, further comprising a comparison / determination circuit that compares the output signal of the latch circuit to detect the frequency inversion state and outputs a detection signal. Said frequency comparison means, even if the command signal for applying a reverse torque by the rotational state command means is outputted, the frequency of the position signal only when less than the predetermined value, the frequency reverse state 3. The motor driving device according to claim 1, wherein a detection operation is performed. From the time when the time corresponding to the previously output section elapses from the end time of the previously output section until the position signal of the next section is detected, the brake switching means the motor drive apparatus according to any one of claims 1 to 3, characterized by selecting a short brake control. Said position detecting means detects a magnetic flux of the field magnet part component of the rotor, according to any one of claims 1 to 4, characterized in that it comprises a position detecting element for generating the position signal Motor drive device. A motor driving device according to any one of claims 1 to 5, as a motor driving device for rotationally driving a recording medium;
Head means for performing at least one of signal reproduction and signal recording on a recording medium;
An information processing means for performing at least one of processing of a reproduction signal reproduced by the head means and signal processing of recording information recorded on a recording medium by the head means.

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