JPH08191591A - Device for controlling drive of brushless motor - Google Patents

Abstract

PURPOSE: To shorten a time from the end of a plugging operation to a spontaneous stop and to make the execution of a reliable quick stop operation possible by conducting a DC brake operation after the plugging operation is conducted on the basis of a motor stop signal. CONSTITUTION: A brake command circuit 6 outputs a plugging signal on the basis of a motor stop signal SS and outputs a DC brake signal DB thereafter. A control circuit 3 makes a brushless motor 4 rotate in one direction by giving an electrification timing signal to a switching circuit 5 on the basis of a position detection signal from a position detecting circuit 9, and gives a reverse rotation electrification timing signal to the switching circuit 5 so as to apply a reverse rotation torque to the brushless motor 4, on the basis of the switchover operation of a rotational direction switchover circuit 7. A DC brake circuit 8 gives DC excitation to stators 4U, 4V and 4W of the brushless motor 4 on the basis of the DC brake signal DB from the brake command circuit 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor drive device in which a brake is applied to a brushless motor which is rotating at a constant speed so as to make a sudden stop.

[0002]

2. Description of the Related Art In a conventional brushless motor, when the rotation is stopped, it is common to simply stop the power supply to the brushless motor to naturally stop the rotation by axial load, air resistance and the like. It was

Further, when it is necessary to suddenly stop the brushless motor, for example, a device for applying a reverse rotation torque for a predetermined time to decelerate the motor, and then naturally stopping it is used.

[0004]

By the way, for example, in a drive control device for a brushless motor used in an optical disk device, a sudden stop of the brushless motor is required for attachment / detachment of the disk, and in particular, since the inertia of the disk is large,
A more complete stop function is needed. However, in the conventional configuration as described above, it takes time to naturally stop after applying the reverse rotation torque, and if the time to apply the reverse rotation torque is too long in order to shorten the time until the natural stop, the reverse occurs. It may rotate in the direction.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a brushless motor which can surely make an abrupt stop in a configuration in which a reverse braking operation is performed in which a reverse torque is applied by a motor stop signal. In order to provide a drive control device.

[0006]

In order to achieve the above object, a drive control device for a brushless motor according to claim 1 of the present invention is a switching circuit for sequentially energizing a plurality of phases of stator windings of the brushless motor. , A position detection circuit that detects the relative position of the rotor and stator windings of the brushless motor and outputs a position detection signal, and a reverse brake signal based on the motor stop signal, and then a DC brake signal. The brake command circuit that outputs, the rotation direction switching circuit that switches the rotation direction based on the reverse rotation brake signal from this brake command circuit, and the energization timing signal to the switching circuit based on the position detection signal from the position detection circuit. The brushless motor is rotated in one direction by giving the brushless motor based on the switching operation of the rotation direction switching circuit. Control means for applying a reverse rotation energization timing signal to the switching circuit so as to apply a reverse rotation torque to the switching circuit, and a DC brake circuit for DC exciting the stator winding of the brushless motor based on the DC brake signal from the brake command circuit. It will be done.

According to a second aspect of the present invention, there is provided a drive control device for a brushless motor, wherein a switching circuit for sequentially energizing a plurality of phases of stator windings of the brushless motor, and a relative position of a rotor and a stator winding of the brushless motor. The position detection circuit that outputs the position detection signal when detecting the current, and continuously outputs the position detection signal at that time when the energization is stopped, and outputs the reverse brake signal based on the motor stop signal, After that, the brake command circuit that outputs a DC brake signal and the operation that switches the rotation direction based on the reverse brake signal from this brake command circuit are performed, and the rotation direction switching that stops the energization of the position detection circuit based on the DC brake signal. Circuit and a switching circuit based on the position detection signal from the position detection circuit The brushless motor is rotated in one direction, and a reverse rotation energization timing signal is applied to the switching circuit so as to apply reverse rotation torque to the brushless motor based on the switching operation of the rotation direction switching circuit. When the position signal does not change, the corresponding stator And a control means for applying a DC excitation timing signal to the switching circuit so that the winding is DC-excited.

In this case, the position detection circuit may be configured to include a hall element, and the rotation direction switching circuit may be configured to switch the direction of the current flowing through the hall element based on the reverse rotation brake signal (claim). 3). Further, the brake command circuit may be provided with a timer means, and the reverse rotation brake signal may be output for the timer time of the timer means (claim 4).

Further, a speed detecting means for detecting the rotation speed of the brushless motor is provided, and the brake command circuit is arranged to stop the output of the reverse brake signal when the speed detected by the speed detecting means becomes a predetermined value or less. You may comprise (Claim 5). Further, the DC brake circuit may be provided with a timer unit so that the DC excitation is performed only for the timer time of the timer unit (claim 6).

Further, the DC brake circuit may be configured to DC excite all of the plural-phase stator windings of the brushless motor (claim 7). The brake command circuit may be configured to stop the output of the DC brake signal when the speed detected by the speed detecting means becomes zero (claim 8).

[0011]

According to the drive control device of the brushless motor of the first aspect, the DC braking operation is performed after the reverse braking operation is performed based on the motor stop signal. Therefore, the DC braking time is used instead of the natural stopping time. Next to
A reliable sudden stop operation is possible.

According to the drive control device of the brushless motor of the second aspect, when the DC braking operation is performed after the reverse braking operation based on the motor stop signal, the rotor and the stator winding of the brushless motor are Since a position detection circuit that detects the relative position of the device and outputs a position detection signal and that outputs the position detection signal at that time continuously for a certain period of time when the energization is stopped, an additional DC brake circuit must be configured. Without it, the DC braking operation can be performed by the switching circuit for normal operation.

According to the drive control device for the brushless motor of the third aspect, since the position detection circuit is configured to include the hall element, the rotation direction switching circuit changes the direction of the current flowing through the hall element based on the reverse brake signal. All you have to do is switch.

According to the drive control device of the brushless motor of the fourth aspect, since the brake command circuit includes the timer means, it is possible to output the reverse braking signal for the timer time of the timer means.

According to the brushless motor drive control device of the present invention, since the speed detecting means for detecting the rotation speed of the brushless motor is provided, the brake command circuit detects that the speed detected by the speed detecting means is less than a predetermined value. The output of the reverse brake signal can be stopped when it becomes.

According to the brushless motor drive control device of the sixth aspect, since the DC brake circuit is provided with the timer means, it is possible to perform the DC excitation for the timer time of the timer means.

According to the drive control device of the brushless motor of the seventh aspect, since the DC brake circuit is configured to perform DC excitation of all the stator windings of a plurality of phases of the brushless motor, all the stator windings are excited. The maximum DC current can be applied to enhance the DC braking effect.

According to the brushless motor drive control device of the present invention, the brake command circuit is constructed so as to stop the output of the DC brake signal when the speed detected by the speed detecting means becomes zero. The DC braking operation can be completed in a short time.

[0019]

[First Embodiment] A first embodiment of the present invention applied to an optical disk device.
An embodiment will be described with reference to FIGS. First, the configuration of the drive control device for the brushless motor will be described with reference to FIG. The motor start / stop signal terminal 1 and the torque control signal terminal 2 are provided with a motor start / stop signal SS and a torque control signal TC from the outside.
Both of them are connected to an input terminal of a control circuit 3 which mainly includes a microcomputer as a control means. The output terminals 5a, 5b and 5c of the U, V and W phases of the switching circuit 5 are U and V connected in a star connection of the brushless motor 4.
, And W-phase stator windings 4U, 4V, and 4W, respectively.

The motor start / stop signal terminal 1 is connected to the input terminal of a one-shot multivibrator 6a which outputs a signal having a constant pulse width, for example, as timer means inside the brake command circuit 6. The output terminal of the one-shot multivibrator 6a has a signal output circuit 6b.
, And the rotation direction signal output terminal of the signal output circuit 6b is connected to the input terminal of the rotation direction switching circuit 7. The reverse torque control signal output terminal of the signal output circuit 6b is connected to the torque control signal terminal 2, and the DC brake start signal output terminal is connected to the input terminal of the DC brake circuit 8.

Output terminals 7a, 7 of the rotation direction switching circuit 7
b is connected to the respective power source input terminals of the Hall elements 9u, 9v and 9w of the position detection circuit 9 which detects the rotational position of the permanent magnet type rotor of the brushless motor 4. Then, the rotation direction switching circuit 7 switches the direction of the current flowing between the output terminals 7a and 7b according to the rotation direction signal DIR from the signal output circuit 6b. One end of each output terminal of the Hall elements 9u, 9v and 9w is grounded, and the other end is connected to each input terminal of the comparators 10u, 10v and 10w having hysteresis characteristics. The DC power supply voltage Va is applied to the other input terminals of the comparators 10u, 10v and 10w by the resistor 11a,
The potential divided by 11b to an appropriate value is applied as a reference voltage for comparison. The input terminals of the comparators 10u, 10v and 10w are connected to the input terminals of the control circuit 3.

The DC brake circuit 8 receives the DC brake signal DB input from the brake command circuit 6 at an input terminal of a one-shot multivibrator 8a which outputs a predetermined pulse width signal as an internal timer means. The output terminal of the one-shot multivibrator 8a is connected to the input terminal of the signal output circuit 8b. The drive signal output terminal of the signal output circuit 8b is connected to the base terminals of the power transistors 12u, 12v, and 12w corresponding to the U, V, and W phases of the brushless motor 4, and the power transistors 12u, 1
2v and 12w collector terminals are switching circuits 5
Of the output terminals 5a, 5b and 5c. The DC power supply voltage Vb is applied to the emitter terminal of the power transistor 12u, and the emitter terminals of 12v and 12w are grounded. The DC brake signal output terminal of the output signal circuit 8b is connected to the input terminal of the control circuit 3.

Next, the operation of this embodiment will be described with reference to FIG. The motor start / stop signal SS input from the outside to the motor start / stop signal terminal 1 is a motor stop signal when it is at a high level and a motor start signal when it is at a low level. The torque control signal TC (F) given from the outside to the torque control signal terminal 2 is large at the time of starting and smaller than this in the normal operating state.

Now, when the motor start / stop signal SS goes to a low level (motor start signal), the control circuit 3 gives a start timing signal to the switching circuit 5 to turn on / off the switching element in the switching circuit 5, so that the brushless An AC voltage is applied to the stator windings 4U to 4W of the motor 4. The control circuit 3 also controls the torque control signal TC.
The switching circuit 5 is PWM-controlled according to the size of (F), and thus the torque of the brushless motor 4 is controlled.

When the brushless motor 4 is started, the Hall elements 9u, 9v and 9w of the position detection circuit 9 output the output voltage, and the output voltage is the comparators 10u, 10v and 1
When the input voltage is 0 w and the input voltage is at a level exceeding the reference voltage, the control circuit 3 outputs a high level rectangular wave signal.
Is output to. The control circuit 3 logically operates the rectangular wave signal as a rotor position detection signal to obtain an energization timing signal, thereby turning on / off the switching element of the switching circuit 5 and setting the brushless motor 4 to the normal operation state. To do.

When the motor start / stop signal SS is changed to a high level (motor stop signal), the torque control signal TC (F) becomes zero potential at this time. Also,
The one-shot multivibrator 6a outputs a pulse having a fixed time width corresponding to the time interval for performing the reverse brake operation by the rising edge of the motor start / stop signal SS. In response to this, the signal output circuit 6b changes the rotation direction signal DIR from low level to high level in order to start the reverse braking operation.
The pulse width output by a is changed only for the time. In response to this, the rotation direction switching circuit 7 reverses the direction of the current applied to the Hall elements 9u, 9v and 9w between the output terminals 7a and 7b.

The Hall elements 9u, 9v and 9w have opposite polarities of the magnetic fields of the rotors of the brushless motor 4 to be detected when the directions of the applied currents are reversed, so that the Hall elements 9u, 9v and 9w are reversed. Receiving the output, comparator 10u,
The phases of the signals that 10v and 10w output to the control circuit 3 are the phases that rotate the brushless motor 4 in the opposite direction. The signal output circuit 6b applies the reverse rotation torque control signal TC (B) to give the reverse rotation torque.
Instead of the torque control signal TC (F) in which the drive is stopped, the torque control signal TC (F) is output to the control circuit 3 only for the duration of the pulse width output by the one-shot multivibrator 6a.

Therefore, the control circuit 3 logically operates the rectangular wave signals from the comparators 10u to 10w to obtain a reverse rotation energization timing signal, thereby turning on / off the switching element of the switching circuit 5, and causing the brushless motor 4 to rotate in reverse torque. Generate. Since such a reverse rotation braking operation is performed only for the duration of the pulse width output by the one-shot multivibrator 6a, the reverse rotation torque is applied to the brushless motor 4 for a certain period of time, and the rotation speed n of the brushless motor 4 sharply decreases. After that, when the rotation direction signal DIR returns to the low level, the direction of the current between the output terminals 7a and 7b returns to normal rotation, the reverse rotation torque control signal TC (B) stops driving the signal, and the reverse rotation braking operation ends. .

Further, the signal output circuit 6b outputs a trigger pulse, which serves as a DC braking operation start signal DB, to the DC braking circuit 8 at the trailing edge of the pulse output by the one-shot multivibrator 6a. The DC braking operation start signal DB is input to the one-shot multivibrator 8a and has a width of a predetermined time (a time interval sufficient for stopping the brushless motor 4) corresponding to the time interval for performing the DC braking operation by the rising edge thereof. Output pulse. The output of the one-shot multivibrator 8a is input to the signal output circuit 8b, the signal output circuit 8b outputs the DC brake signal DBC to the control circuit 3, and the control circuit 3 accordingly stops the switching control of the switching circuit 5. By doing so, the driving of the brushless motor 4 is stopped.

Further, the signal output circuit 8b switches the power transistors 12u, 12v and 12w from the off state to the on state, respectively.
The levels of the drive signals Tu, Tv, and Tw output to the base terminals of u, 12v, and 12w are switched from high, low, low to low, high, high, respectively. Then, from the U-phase stator winding 4U of the brushless motor 4 to V and W
A DC current flows through the phase stator windings 4V and 4W to perform DC excitation, whereby a DC braking operation is performed, and the rotation of the brushless motor 4 is rapidly stopped.

When the time of the pulse width output by the one-shot multivibrator 8a has elapsed, the signal output circuit 8b
Resets the levels of the drive signals Tu, Tv, and Tw to high, low, and low to turn off the power transistors 12u, 12v, and 12w, respectively, and outputs the DC brake signal DBC to the control circuit 3. And the DC braking operation ends.

As described above, according to the present embodiment, after the rapid deceleration is performed by the reverse braking operation which gives the reverse torque to the brushless motor 4 based on the motor stop signal, the direct current is applied to the brushless motor 4 by the direct current excitation. Since the brake operation is performed, it is possible to shorten the time from the end of the reverse brake operation, which is required when only the reverse brake is conventionally used, to the natural stop, and a quick and reliable stop operation can be performed.

3 and 4 show a second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below. Further, FIG. 4 shows each signal output. The rotation direction signal output terminal and the DC brake signal terminal of the signal output circuit 13a arranged inside the brake command circuit 13 are connected to the respective input terminals of the rotation direction switching circuit 14. In addition, the brake command circuit 13
The reverse control torque control signal output terminal of is the torque control signal terminal 2
Connected with. The output terminals 14a and 14b of the rotation direction switching circuit 14 are connected to the respective current input terminals of the Hall elements 9u to 9w.

In the above structure, the same operation as that of the first embodiment is performed until the end of the reverse braking operation. The DC brake signal DB2 is a signal output at the falling edge of the output pulse of the one-shot multivibrator 6a, and outputs a pulse having a predetermined time width according to the time interval for performing the DC braking operation. The rotation direction switching circuit 14 is
DC brake signal DB2 after reverse brake operation is completed
Is input, the levels of the output terminals 14a and 14b are both set to high (both may be low), and the supply of current to the Hall elements 9u to 9w of the position detection circuit 9 is stopped. Then, the output terminals of the Hall elements 9u to 9w are in a high impedance state, and the comparators 10u to 10w receiving the output signals of the Hall elements 9u to 9w have the hysteresis characteristic, and thus retain the previous output state.

Therefore, the energization timing signal from the control circuit 3 is held and becomes the DC excitation timing signal,
A DC current flows through any one of the stator windings 4U to 4W of the brushless motor 4 to perform a DC braking operation.
When the DC braking operation ends in accordance with the pulse width of the DC braking signal DB2, the output terminals 14a and 14b of the rotation direction switching circuit 14 have hall elements 9u to 9d during normal operation.
It switches to the direction of the current flowing with respect to w.

Therefore, according to the second embodiment, the comparator 10
Since the input of u to 10w is set to the high impedance state, the hysteresis state of the comparators 10u to 10w is used to hold the output state of the switching circuit 5 to perform the DC braking operation. Unlike the example, it is not necessary to configure the brake circuit 8, and the number of components can be reduced.

FIG. 5 shows a third embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below. The rotation speed detector 15 as speed detection means is composed of a large number of permanent magnets that rotate with the rotation of the brushless motor 4 and Hall elements that detect the magnetic force thereof, and detects the rotation speed of the brushless motor 4.

The output terminal of the rotation speed detector 15 is connected to the input terminal of the brake command circuit 16. The signal output circuit 16a inside the brake command circuit 16 is
The reverse rotation braking operation is started by the rising edge of the motor start / stop signal SS as in the first embodiment. However, the reverse rotation braking operation refers to the output signal of the rotation speed detector 15 until the rotation speed of the brushless motor 4 reaches a predetermined value. When it decreases, the process ends, and then a trigger pulse that is a DC brake start signal DB is output to the DC brake circuit 8. The subsequent operation is the same as in the first embodiment.

Therefore, according to the third embodiment, the rotation speed detector 15 for detecting the rotation speed of the brushless motor 4 is provided, and the brake command circuit 16 has this rotation speed detector 15.
Since the output of the reverse brake signal is stopped when the detected speed of the brushless motor 4 becomes equal to or lower than the predetermined value, regardless of the rotation speed of the brushless motor 4, when the rotation speed of the brushless motor 4 decreases to the predetermined value. Since the reverse rotation braking operation can be surely ended with, it is suitable for the brushless motor 4 having a variable rotation speed.

FIG. 6 shows a fourth embodiment of the present invention. The same parts as those in FIG. 5 are designated by the same reference numerals and the description thereof will be omitted. Only different parts will be described below. Brake command circuit 1
The output terminal of the DC brake signal DB3 output by 7 is connected to the input terminal of the DC brake circuit 18 and at the same time connected to the input terminal of the control circuit 3. The signal output circuit 18a inside the DC brake circuit 18 directly receives the DC brake signal DB3. The DC brake signal DBC output from the DC brake circuit 8 to the control circuit 3 in FIG. 1 or 5 is deleted.

In the above configuration, the brake command circuit 1
Reference numeral 7 refers to the output signal of the rotation speed detector 15 after starting the reverse braking operation, performs the reverse braking operation until the rotation speed of the brushless motor 4 reaches a predetermined value, and then starts the DC braking operation. The operation up to this point is similar to that of the third embodiment, but the subsequent DC braking operation is performed until the output of the rotation speed detector 15 becomes zero. That is, the DC braking operation time is determined by the output time of the DC braking signal DB3 output to the DC braking circuit 18 and the control circuit 3 by the signal output circuit 17a in the brake command circuit 17, and the control circuit 3 switches during that period. The control of the circuit 5 is stopped to stop the driving of the brushless motor 4, and the DC braking circuit 18 performs the DC braking operation.

For the DC brake signal DB3, after the DC braking operation is started, the signal output circuit 17a refers to the output of the rotation speed detector 15 and detects that the rotation speed of the brushless motor 4 has become zero. This is a significant signal. That is, the DC braking operation is performed until the rotation of the brushless motor 4 is completely stopped, and the DC braking operation is ended after detecting the stop of the rotation of the brushless motor 4. The rotation stop of the brushless motor 4 can be detected by the fact that the output signal of the Hall element of the rotation speed detector 15 has stopped changing.

Therefore, according to the fourth embodiment, the brake command circuit 17 is configured to stop the output of the DC brake signal when the detected speed of the rotation speed detector 15 becomes zero. Since the DC braking operation can be ended almost simultaneously with the stop of 4 and the time for performing the DC excitation can be minimized, the power consumption can be suppressed.

In the above first, third and fourth embodiments,
Although the DC excitation is performed for all three phases when the DC braking operation is performed, the present invention is not limited to this, and the DC excitation may be performed for any two phases.
Further, by grounding the neutral point of the brushless motor 4, the DC excitation may be performed for any one phase or a plurality of phases including the second embodiment. In the above embodiment, the one-shot multivibrator is used as the timer means, but an IC that counts a predetermined number of clock pulses may be used.

[0045]

Since the present invention is as described above,
The following effects are obtained. According to the brushless motor drive control device of the first aspect, the DC braking operation is performed after the reverse braking operation is performed based on the motor stop signal. Stop operation is possible.

According to the drive control device of the brushless motor of the second aspect, when the DC braking operation is performed after the reverse braking operation based on the motor stop signal, the rotor and the stator winding of the brushless motor are By detecting the relative position of the position detection signal and outputting the position detection signal, and when the energization is stopped, the position detection circuit that continuously outputs the position detection signal at that time is used for only the switching circuit for normal operation. Since the DC braking operation can be performed, the number of parts such as the power transistor that excites the stator winding for the DC braking operation can be reduced, and the manufacturability and the quality reliability can be improved.

According to the drive control device of the brushless motor of the third aspect, since the position detecting circuit is constituted by the hall element, the rotation direction switching circuit switches the direction of the current flowing through the hall element based on the reverse braking signal. Therefore, the circuit can be simply constructed.

According to the drive control device of the brushless motor of the fourth aspect, since the brake command circuit includes the timer means, it can be configured to output the reverse brake signal for the timer time of the timer means.

According to the drive control device of the brushless motor of the fifth aspect, since the speed detection means for detecting the rotation speed of the brushless motor is provided, the brake command circuit detects that the speed detection of this speed detection means is a predetermined value or less. When this happens, the output of the reverse brake signal can be stopped, and the reverse brake operation can be reliably completed at the specified low speed rotation regardless of the rotation speed of the brushless motor.
Suitable for brushless motors with variable speed.

According to the drive control device of the brushless motor of the sixth aspect, since the DC brake circuit is provided with the timer means, it is possible to perform the DC excitation for the timer time of the timer means.

According to the drive control device of the brushless motor of the seventh aspect, since the DC brake circuit is configured to DC-excite all the stator windings of the plurality of phases of the brushless motor, all the stator windings are excited. The maximum DC current can be applied to enhance the DC braking effect.

According to the brushless motor drive control device of the present invention, the brake command circuit is configured to stop the output of the DC brake signal when the speed detected by the speed detecting means becomes zero. Since the DC braking operation can be completed almost at the same time when the motor is stopped and the time for performing the DC excitation can be minimized, the power consumption can be suppressed.

[Brief description of drawings]

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

[Fig. 2] Timing chart

FIG. 3 is a diagram corresponding to FIG. 1 of the second embodiment of the present invention.

FIG. 4 is a view corresponding to FIG.

FIG. 5 is a diagram corresponding to FIG. 1 of the third embodiment of the present invention.

FIG. 6 is a diagram corresponding to FIG. 1 of a fourth embodiment of the present invention.

[Explanation of symbols]

1 is a motor start / stop signal terminal, 2 is a torque control signal terminal, 3 is a control circuit (control means), 4 is a brushless motor, 5 is a switching circuit, 6 is a brake command circuit, 7
Is a rotation direction switching circuit, 8 is a DC brake circuit, 9 is a position detection circuit, 9u, 9v and 9w are hall elements, 10
u, 10v and 10w are comparators, 13 is a brake command circuit, 14 is a rotation direction switching circuit, 15 is a rotation speed detector (rotation speed detecting means), 16 and 17 are brake command circuits, and 18 is a DC brake circuit. .

Claims (8)

[Claims] 1. A switching circuit for sequentially energizing multiple-phase stator windings of a brushless motor, and a position for detecting a relative position between a rotor and a stator winding of a brushless motor and outputting a position detection signal. The reverse rotation brake signal is output based on the detection circuit and the motor stop signal,
After that, a brake command circuit that outputs a DC brake signal, a rotation direction switching circuit that switches the rotation direction based on the reverse braking signal from the brake command circuit, and a position detection signal from the position detection circuit The brushless motor is rotated in one direction by applying an energization timing signal to the switching circuit, and a reverse rotation energization timing signal is applied to the switching circuit so that reverse rotation torque is applied to the brushless motor based on the switching operation of the rotation direction switching circuit. A drive control device for a brushless motor, comprising: a control means; and a DC brake circuit for DC-exciting a stator winding of the brushless motor based on a DC brake signal from the brake command circuit. 2. A switching circuit for sequentially energizing a plurality of phases of stator windings of a brushless motor, and detecting a relative position between a rotor and a stator winding of the brushless motor and outputting a position detection signal. , When the energization is stopped, the position detection circuit that continuously outputs the position detection signal at that time for a fixed time, and the reverse rotation brake signal based on the motor stop signal are output.
After that, a brake command circuit that outputs a DC brake signal and an operation that switches the rotation direction based on the reverse brake signal from this brake command circuit are performed, and rotation that stops the energization to the position detection circuit based on the DC brake signal. A brushless motor is rotated in one direction by applying an energization timing signal to the switching circuit based on a direction switching circuit and a position detection signal from the position detection circuit, and the brushless motor is switched based on the switching operation of the rotation direction switching circuit. A reverse rotation energization timing signal is applied to the switching circuit so as to apply a reverse rotation torque to the switching circuit, and a DC excitation timing signal is applied to the switching circuit so that the corresponding stator winding is DC-excited when the position signal does not change. Brushless comprising control means Over other drive control device. 3. The position detecting circuit is configured to include a Hall element, and the rotation direction switching circuit is configured to switch a direction of a current flowing through the Hall element based on a reverse brake signal. The drive control device for the brushless motor according to claim 1 or 2. 4. The brushless motor according to claim 1, wherein the brake command circuit includes timer means, and is configured to output a reverse brake signal for a timer time of the timer means. Drive controller. 5. A speed detecting means for detecting the rotational speed of the brushless motor is provided, and the brake command circuit stops outputting the reverse rotation braking signal when the speed detected by the speed detecting means becomes a predetermined value or less. The drive control device for the brushless motor according to claim 1, wherein the drive control device is configured. 6. The drive control device for a brushless motor according to claim 1, wherein the DC brake circuit is provided with timer means, and is configured to perform DC excitation for a timer time of the timer means. . 7. The drive control device for a brushless motor according to claim 1, wherein the DC brake circuit is configured to DC-excite all stator windings of a plurality of phases of the brushless motor. 8. The brushless motor according to claim 5, wherein the brake command circuit is configured to stop the output of the DC brake signal when the detected speed of the speed detecting means becomes zero. Drive controller.