JPH06105589A - Drive controller for dc brushless motor - Google Patents

Abstract

PURPOSE:To prevent a DC brushless motor from becoming impossible starting when the motor to be used for a magnetic disk apparatus increases a frictional force in a forward rotating direction. CONSTITUTION:A signal indicating that a motor 14 rotates is input to a CPU 11. When the motor 14 does not rotate within a predetermined period after starting, the CPU 11 once controls so as to generate torque in a reverse rotating direction. Thus, when the motor 14 reversely rotates, it is controlled so as to again in the forward rotating direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive controller for a DC brushless motor, and more particularly to a drive controller for a DC brushless motor used in a spindle motor of a magnetic disk device.

[0002]

2. Description of the Related Art A conventional drive control device for a DC brushless motor is shown in FIG. The output of the index sensor 66, which outputs one pulse per revolution by the rotation of the motor 64, is input to the CPU 61, whereby the difference between the current speed and the reference speed is calculated, and a torque command is issued to the drive circuit 63.

The hall sensor 65 detects the rotor position of the motor 64, a rotor position signal is input to the logic circuit 62, the excitation position is switched so that the rotor rotates in the forward rotation direction, and a drive signal is sent to the drive circuit 63. The drive circuit 63 sends a current proportional to the torque command from the CPU 61 to the winding of the motor 64 by this signal. In this way, rotation control and speed control are performed.

A DC brushless motor drive control device which does not use a hall sensor is shown in FIG. Instead of the output of the Hall sensor 65 of FIG.
The counter electromotive force generated at the time of rotation is compared by the counter electromotive force detection circuit 47 between the midpoint of the winding and the driving point, and this is input to the logic circuit 42 as a rotor position signal. Similarly, rotation control and speed control are performed.

FIG. 9 is a flow chart showing processing at the time of starting in the conventional DC brushless motor drive control device. First, the drive power supply is turned on to detect whether or not the motor is rotating. Then, when the motor starts rotating, normal control is performed. If the motor does not start rotating for a certain period of time after the start of startup, it is determined that the system has failed.

[0006]

In this conventional DC brushless motor drive control device, since the motor does not rotate in the constant rotation direction, dust or the like adheres between the magnetic head and the magnetic disk medium in the magnetic disk device. In a situation where the friction in the forward rotation direction is large, the friction in the reverse rotation direction is small, and even if the rotation can be started in the reverse rotation direction, there is a problem that it cannot be started.

[0007]

According to the present invention, in a drive controller for a DC brushless motor using a position sensor for controlling rotation, a rotation detecting sensor for detecting the presence or absence of rotation of the DC brushless motor, and a sensor for detecting the rotation. When the DC brushless motor does not rotate within a predetermined period after the start of the DC brushless motor output, the switching means switches the rotation direction of the DC brushless motor.

Further, instead of the rotation detection sensor, the position sensor detects whether or not the DC brushless motor is rotating, and the position sensor outputs the DC signal.
When the brushless motor does not rotate within a predetermined period after the start of activation, the switching unit may switch the rotation direction of the DC brushless motor, and instead of the rotation detection sensor, the DC brushless motor is rotated when the motor rotates. A back electromotive force detection circuit for detecting a back electromotive force generated from a winding is provided, the presence or absence of rotation is detected by the output of the back electromotive force detection circuit, and the DC brushless motor is output by the back electromotive force detection circuit. The switching means may switch the rotation direction of the DC brushless motor when the motor does not rotate within a predetermined period after the start of the.

Next, in a drive controller for a DC brushless motor that does not use a position sensor, a counter electromotive force detection circuit for detecting a counter electromotive force generated in the motor winding when the DC brushless motor is rotated, and a counter electromotive force detection circuit. When the presence or absence of rotation is detected by the output of the power detection circuit, and when the output of the counter electromotive force detection circuit does not rotate within a predetermined period after the start of activation of the DC brushless motor, other than the current excitation position of the DC brushless motor. And a switching means for switching the excitation to any phase. Further, when the DC brushless motor is started up, there is provided excitation direction determination means for detecting the stop position of the rotor of the DC brushless motor by pulse driving and determining the excitation direction, and within a predetermined period after starting the activation of the DC brushless motor. When not rotating, the switching means may switch the excitation direction of the DC brushless motor from the current excitation direction to the reverse rotation direction.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a DC brushless motor drive controller according to a first embodiment of the present invention.
3 is a flow chart showing processing at the time of startup of this embodiment. The output of the index sensor 16 is input to the CPU 11, and the CPU 11 detects that the motor 14 has rotated by changing the output of the index sensor 16. The three Hall sensors 15 are the motor 1
4 detects the rotor position, and the logic circuit 12 sends a phase switching signal 102 for switching the excitation position of the rotor to the drive circuit 13. The drive circuit 13 is the CPU 11
A drive current 103 is supplied to the motor 14 according to a torque command 101 from the.

Next, the index sensor 16 is sent within a fixed time after the CPU 11 sends a torque command to the drive circuit 13.
If there is no change in the signal from, that is, if the motor 14 is stopped, the CPU 11 sends a rotation direction switching signal 104 to the logic circuit 12 to switch the logic so that the motor 14 rotates in the reverse rotation direction.

When the motor 14 starts to rotate due to this switching, the CPU 11 sends a rotation direction switching signal 104 to the logic circuit 12 again, and switching is performed so as to return to a logic such that the motor 14 rotates in the forward rotation direction. .

FIG. 2 is a block diagram showing a DC brushless motor drive controller according to a second embodiment of the present invention. In this embodiment, the output of one of the three Hall sensors 25 is input to the CPU 21, and the output of the Hall sensor 25 changes, so that the CPU 21 detects that the motor 24 has rotated.

Hereinafter, as in the case of the first embodiment,
When the output of the hall sensor 25 does not change within a certain time after the CPU 21 sends the torque command to the drive circuit 23, the CPU 21 sends the rotation direction switching signal 1 to the logic circuit 22.
04 is sent to switch the logic so that the motor 24 rotates in the reverse rotation direction.

When the motor 24 starts to rotate due to this switching, the CPU 21 again sends a rotation direction switching signal to the logic circuit 22 to perform switching so as to return to a logic such that the motor 24 rotates in the forward rotation direction.

FIG. 3 is a block diagram showing a third embodiment of the present invention. A counter electromotive force detection circuit 37 that detects the counter electromotive force of one of the drive phases of the motor 34 is provided. As a result, when the motor 34 rotates, a counter electromotive force is generated, so that the counter electromotive force detection circuit 37 outputs a signal. This output is connected to the CPU 31, and if the motor 34 does not rotate within a fixed time after the CPU 31 sends a torque command to the drive circuit 33, the above-mentioned switching is performed.

FIG. 4 is a block diagram showing a fourth embodiment of the present invention. In this embodiment, since the motor does not use the Hall sensor, the CPU 41 sends a signal for driving an arbitrary phase to the logic circuit 42 at the time of starting. As a result, if the back electromotive force generated by the rotation of the motor 44 cannot be detected by the back electromotive force detection circuit 47 within a certain time after the CPU 41 sends the torque command to the drive circuit 43, another phase is excited. CPU 41 is a logic circuit 42
Send a signal to.

As a result, when the motor 44 rotates and the back electromotive force can be detected, the input to the logic circuit 42 is switched to the output from the back electromotive force detection circuit 47. Even if the excitation is switched to another phase, if the back electromotive force cannot be detected within the fixed time, the phase is switched to another phase and the same control is performed.

FIG. 5 is a block diagram showing a fifth embodiment of the present invention, and FIG. 7 is a flow chart showing processing at the time of starting in this embodiment. Although this embodiment is also a motor that does not use a Hall sensor, it has a control method for determining the excitation phase of the motor 51 in the positive rotation direction by outputting a pulsed drive signal from the CPU 51 at the time of startup, and it is determined based on the result. The drive signal for the generated excitation phase is sent from the CPU 51 to the logic circuit 52. As a result, if the counter electromotive force generated by the rotation of the motor 51 cannot be detected by the counter electromotive force detection circuit 57 within a certain time after the CPU 51 sends the torque command to the drive circuit 53, the previously determined excitation phase is Excitation is applied to the phase in which torque is generated in the opposite direction.

As a result, when the motor 51 rotates and the back electromotive force can be detected, the input to the logic circuit 52 is switched to the output from the back electromotive force detection circuit 57,
Control to rotate in the forward direction.

[0022]

As described above, according to the present invention, when the friction between the magnetic head and the magnetic disk medium increases in the forward rotation direction in the magnetic disk device, torque is once applied in the reverse rotation direction to enable the motor to rotate. After that, the operation of turning in the forward rotation direction has an effect of avoiding a state where the motor cannot be started due to friction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a block diagram showing a third embodiment of the present invention.

FIG. 4 is a block diagram showing a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a fifth embodiment of the present invention.

FIG. 6 is a flowchart showing processing at the time of startup in the first embodiment of FIG.

FIG. 7 is a flowchart showing processing at the time of startup in the fifth embodiment of FIG.

FIG. 8 is a block diagram showing a conventional example.

FIG. 9 is a flowchart showing processing at the time of startup in a conventional example.

[Explanation of symbols]

 11, 21, 31, 41, 51, 61 CPU 12, 22, 32, 42, 52, 62 Logic circuit 13, 23, 33, 43, 53, 63 Drive circuit 14, 24, 34, 44, 54, 64 Motor 15, 25, 35, 65 Hall sensor 16, 26, 36, 66 Index sensor 37, 47, 57 Back electromotive force detection circuit 101 Torque command signal 102 Phase switching signal 103 Drive current 104 Rotation direction switching signal 105 Start signal

Claims (5)

[Claims] 1. D using a position sensor for rotation control
In the drive controller for the C brushless motor, the DC
A rotation detection sensor that detects whether or not the brushless motor is rotating, and a switching unit that switches the rotation direction of the DC brushless motor when the DC brushless motor does not rotate within a predetermined period after the start of activation of the DC brushless motor due to the output from the sensor. A DC brushless motor drive control device comprising: 2. The DC brushless motor drive control device according to claim 1, wherein instead of the rotation detection sensor, the position sensor detects whether or not the DC brushless motor is rotating, and the output of the position sensor detects the rotation of the DC brushless motor. D
The DC brushless motor drive control device, wherein the switching means switches the rotation direction of the DC brushless motor when the C brushless motor does not rotate within a predetermined period after the start of activation. 3. The DC brushless motor drive control device according to claim 1, wherein instead of the rotation detection sensor, a counter electromotive force detection circuit that detects a counter electromotive force generated from a motor winding when the DC brushless motor rotates. The switching means detects the presence / absence of rotation by the output of the back electromotive force detection circuit, and when the output from the back electromotive force detection circuit does not rotate within a predetermined period after the start of activation of the DC brushless motor. Is a DC brushless motor drive control device, wherein the rotation direction of the DC brushless motor is switched. 4. A drive control device for a DC brushless motor that does not use a position sensor, and a back electromotive force detection circuit for detecting a back electromotive force generated in the motor winding when the DC brushless motor rotates, and a back electromotive force detection circuit. When the presence or absence of rotation is detected by the output of the detection circuit, and when the DC brushless motor does not rotate within a predetermined period after the start of activation of the DC brushless motor due to the output of the counter electromotive force detection circuit, a value other than the current excitation position of the DC brushless motor is detected. A DC brushless motor drive control device comprising: a switching unit that switches excitation to an arbitrary phase. 5. The DC brushless motor drive control device according to claim 4, further comprising an excitation direction determining means for detecting a stop position of a rotor of the DC brushless motor and determining an excitation direction by pulse driving when the DC brushless motor is started. If the DC brushless motor does not rotate within a predetermined period after the start of activation, the switching unit is configured to operate the DC
A DC brushless motor drive control device, characterized in that the excitation direction of the brushless motor is switched from the current excitation direction to the reverse rotation direction.