JPH05244794A - Driving circuit for two-phase unipolar sensorless motor - Google Patents

Abstract

PURPOSE:To obtain a driving circuit for a two-phase unipolar sensorless motor which can select an immediate restart in response to a rotating speed of the motor or restart after a predetermined time at the time of a restart command of the motor. CONSTITUTION:The driving circuit for a two-phase unipolar sensorless motor comprises, in addition to a stator and a rotor, a comparator adapted to fan motors having different magnetic and electric stationary points to decide an amplitude of a counterelectro-motive force generated across a coil and a logic circuit for deciding an output voltage in response to the comparison result, a pulse generator 5 such as integrators 16-18 for generating a one-shot pulse, a filter 6 such as an integrator 24 for passing only an initial one-shot pulse, etc. A restart is accepted after a predetermined time is elapsed when a rotating speed of the motor is low at the time of outputting a start command after a stop command.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-phase unipolar sensorless motor, and more particularly to a fan motor having a magnetic stop point and an electric stop point which are different from each other, and is restarted immediately in accordance with the number of rotations of the motor when a restart command is issued. The present invention relates to a technique effective when applied to a drive circuit of a two-phase unipolar sensorless motor in which it is possible to select whether to apply power or to restart after a fixed time.

[0002]

2. Description of the Related Art Conventionally, as a fan motor for cooling or the like, for example, a stator that generates a magnetic field in an excited state and a rotor that obtains a rotational force by electromagnetic interaction with the stator are used, and an induced voltage of a coil is used. A sensorless type brushless motor has come to be used, and in many cases, rotation control is performed by an electronic circuit made into a semiconductor chip.

In this case, as the rotor rotates, the magnet fixed to the rotor moves, so that the magnetic flux penetrating the stator changes with time, and this change in magnetic flux causes counter-electromotive force in the coil wound around the stator. Electric power is generated.

However, at the time of starting the motor, the motor is in a stopped state and no counter electromotive force is generated in the coil.
The rotor is moved to the electrical stop point by forcibly exciting the coil on one side regardless of the position of the stator and rotor, and after the rotor starts rotating, the magnitude of the back electromotive force generated at both ends of the coil is reduced. Rotation control is performed as a switching signal.

That is, when the motor stops, it always stops at the magnetic stop point. Further, in the case of the two-phase unipolar motor, no torque is generated even if the current is applied at the electrical stop point. Therefore, in order to prevent the inability to restart when the motor stops at the electric stop point, the magnetic stop point and the electric stop point are shifted so that the motor does not stop at the electric stop point. There is.

Further, when the motor is restarted, for example, when the motor is commanded to start, the motor is completely stopped, or in the forward rotation direction at a relatively high rotational speed that generates a large back electromotive force that can be detected by the comparator. If it is rotating, the motor can be rotated in the forward direction at the rated speed.

Further, when a restart command is issued during deceleration, the excitation of both coils is unconditionally prohibited for a predetermined time in order to prevent the motor from rotating in the reverse direction, so that the motor stops completely. After waiting, it receives a restart command and is started.

[0008]

However, in the prior art as described above, if a restart command is issued before the motor has been stopped, for example, after issuing a stop command, the motor continues to rotate in the reverse direction. There is a problem.

Further, in the method of unconditionally rejecting the start command for a certain period of time after issuing the stop command and waiting until the motor is completely stopped, there is a problem that it takes too much time to restart the motor.

Therefore, an object of the present invention is to provide a two-phase unipolar that can be selected when a motor restart command is issued, depending on the number of rotations of the motor, whether to restart immediately or restart after a certain period of time. It is to provide a drive circuit for a sensorless motor.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0012]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the drive circuit of the two-phase unipolar sensorless motor of the present invention is provided with a stator that generates a magnetic field in an excited state and a rotor that obtains a rotational force by electromagnetic interaction with the stator, and is at the cogging stop position. A two-phase unipolar sensorless motor having a magnetic stop point and an electric stop point that is an electric lock position different from each other,
A pulse generation circuit that generates a one-shot pulse for a predetermined time during a start command and when the cycle of the motor rotation frequency is longer than the reference value, and a first pulse generation circuit from the pulse generation circuit after the start command and before the stop command. A filter circuit that allows only one-shot pulses to pass through is provided.

When the motor is restarted,
The braking time for braking the motor in the motor stop operation and the excitation prohibition time for prohibiting the excitation of the motor coil are set in advance.

[0015]

According to the above-mentioned drive circuit of the two-phase unipolar sensorless motor, by providing the pulse generation circuit and the filter circuit, when the motor restart command is issued, the engine is restarted immediately according to the rotation frequency of the motor, Alternatively, it is possible to select whether to reject the start command for the pulse width time of the one-shot pulse that has passed through the filter circuit and restart after a certain time.

That is, the fact that the frequency becomes high when the number of rotations of the motor is high and conversely becomes low when the number of rotations of the motor is low is used. To detect whether the frequency is high or low, the counter electromotive force of the motor is detected by the comparator. An FG (Frequency Generator) signal generated by comparing the magnitudes of the back electromotive forces at both ends of the coil is used.

For example, if the number of rotations of the motor is relatively high at the time when the start command is issued after the stop command is issued, that is, if the cycle of the FG signal is shorter than the cycle of the reference signal, the start command is accepted and the motor is accepted. Continues to rotate.

On the other hand, once the stop command is issued, the selection information of the filter circuit is cleared, and when the start command is issued next, only the first one-shot pulse passes through the filter circuit for the first time, and after this passage time. Reverse rotation can be prevented by restarting.

As a result, even if a restart command is issued while the motor is rotating, the motor does not rotate in the reverse direction, and if the motor is rotating at a relatively high rotational speed, the restart command is issued. Immediately continues rotating, so that the time required to restart the motor can be shortened.

In the motor stop operation, the braking time and the excitation prohibition time are set, so that the motor is first braked to reduce the rotation speed of the motor, and then the excitation of the motor coil is prohibited to prevent the motor from operating. You can wait until it completely stops before you restart.

As a result, the motor stop time can be shortened rather than waiting for the motor to stop naturally by the braking action, and the time required for restarting the motor can be shortened.

Further, since the excitation is prohibited until the minute vibration near the stop point of the motor is stopped and the restart command is accepted after the motor is completely stopped, the reverse rotation of the motor can be prevented.

[0023]

Embodiment 1 FIGS. 1 and 2 are circuit diagrams showing a drive circuit of a two-phase unipolar sensorless motor which is an embodiment of the present invention.

First, referring to FIG. 1 and FIG.
The configuration of the drive circuit of the single-phase unipolar sensorless motor will be described.

The drive circuit of this embodiment comprises, for example, a stator that generates a magnetic field in the excited state, and a rotor that obtains a rotational force by electromagnetic interaction with this stator, and a magnetic stationary point that is a cogging stop position. It is applied to a fan motor that has an electrical stop point that is an electrical lock position, and it determines the magnitude of the back electromotive force generated at both ends of each coil. Logic circuit 3, which determines the output voltage by
4, a pulse generation circuit 5 for generating a one-shot pulse, a filter circuit 6 for passing only the first one-shot pulse, and the like.

At the time of the motor restart command, whether to immediately restart according to the rotation frequency of the motor or reject the start command for the pulse width time of the one-shot pulse and restart after a certain time. You can choose.

Each of the comparators 1 and 2 has one non-inverting terminal, which is an input terminal, connected to the positive voltage side of the coils L1 and L2 whose common is connected to the constant voltage (+ V _DD ) via the diode D, The other inverting terminal has resistors R1 and R2
Is connected to the negative voltage side of the coils L1 and L2 via the, and output terminals are connected to the logic circuits 3 and 4. And
The two counter electromotive force voltages input to the comparators 1 and 2 are compared, and the output voltage to the logic circuits 3 and 4 is the resistances R1 to R1.
It is set to Lo level or Hi level based on R6 or the like.

The logic circuits 3 and 4 are provided with NOT elements 7 and 8, AND elements 9 and 10, AND elements 11 and 12, and transistors 13 and 14, respectively.
Either one of the transistors 13 and 14 is turned on or both of them are turned off according to the output of 2.

Input signals from the comparators 1 and 2 and an input terminal (IN) are input to the AND elements 9 and 10, respectively.
To the resistors R7 and R8, an input signal input to the constant voltage via the transistor 15 whose collector terminal is connected via the resistor R9, and the output inversion signal of the other comparators 2 and 1.

Further, the output signals of the AND elements 9 and 10 are input to one input terminals of the AND elements 11 and 12, respectively, and the coil excitation prohibiting signal from the filter circuit 6 is input to the other input terminals. Transistor 1 connected through resistors R10 and R11 by AND operation
3 and 14 are turned on / off to determine the excitation states of the coils L1 and L2.

The pulse generation circuit 5 includes an integrated circuit 16 for generating a discrimination reference signal for fast / slow rotation of the motor, and an integrated circuit 17 for comparing the discrimination reference signal of the integrated circuit 16 with the frequency of the FG signal. , An integrated circuit 18 for setting the excitation inhibition time of the coils L1 and L2, and a plurality of NOT elements 19
-23, resistors R12-R16 and capacitors C1-C
4 and.

The integrated circuit 17 includes the comparator 1
On the basis of the input signal from the input terminal, the input signal input from the input terminal through the transistor 15, and the determination reference signal from the integrated circuit 16, and the frequency cycle of the FG signal is longer than the determination reference value during the start command. In this case, the one-shot pulse for inhibiting the excitation of the coils L1 and L2 is generated for a predetermined time through the integrated circuit 18.

The filter circuit 6 includes an integrated circuit 24 that passes only one-shot pulses, and NOT elements 25 and 26.
And OR element 27, and after the start command,
And before the stop command, the integrated circuit 18 of the pulse generation circuit 5
Only the first one-shot pulse output from is passed to the AND elements 11 and 12 of the logic circuits 3 and 4 as a coil excitation inhibition signal for a certain period of time, and the excitation of the coils L1 and L2 is inhibited for this period of time. It has become so.

Next, the operation of this embodiment will be described.

For example, when the rotation speed of the motor is high when the start command is issued, the comparators 1, 2,
The NOT elements 7 and 8, the AND elements 9 and 10 and the AND elements 11 and 12 operate to operate the respective transistors 13,
Two-phase coil L by turning ON / OFF of 14
1 and L2 are alternately excited. As a result, at the time of the restart command, the rotation is continued when the rotation speed of the motor is high.

On the other hand, when the rotation speed of the motor is low when the start command is issued, the integrated circuit 18, the NOT element 26, the integrated circuit 24 and the OR element 27 operate through the integrated circuits 16 and 17, and only for a fixed time. A command for prohibiting the excitation of the coil is sent to the AND elements 11 and 12.

In this case, the integrated circuit 16 generates a discrimination reference signal for the fast / slow rotation of the motor, and the integrated circuit 17 further produces a discrimination reference for the frequency of the FG signal and the fast / slow rotation of the motor. The signal is compared and the integrated circuit 18 sets the time during which the excitation of the coil is prohibited.

After that, the comparators 1 and 2, the NOT elements 7 and 8, the AND elements 9 and 10 and the AND elements 11 and 1
2 operates to alternately excite the two-phase coils L1 and L2. As a result, at the time of the restart command, when the rotation speed of the motor is slow, the restart is possible after the time of the one-shot pulse width has elapsed.

Subsequently, when a stop command is issued, a command A for prohibiting the excitation of the coils L1 and L2 is issued.
Send to the ND elements 9 and 10. Then, the selection information of the filter circuit 6 is cleared, and the selection standby state at the time of the motor restart command is entered.

Therefore, according to the drive circuit of the two-phase unipolar sensorless motor of this embodiment, the integrated circuits 16 to 18 and the NOT elements 19 to 23 as the pulse generation circuit 5 are provided.
By including the integrated circuit 24 as the filter circuit 6, the NOT elements 25 and 26, the OR element 27, etc., when the stop command is issued and the start command is issued, when the rotation speed of the motor is relatively high, It accepts the start command as it is and enables the motor to be restarted immediately. Conversely, when the motor rotation speed is low, it is possible to accept the restart after a certain period of time, thereby responding to the restart command while the motor is rotating. Can also eliminate the reverse rotation of the motor.

In particular, when the present invention is applied to a fan motor as in this embodiment, the motor can be rotated in the correct direction at the time of restarting, so that a predetermined cooling capacity as a cooling fan can be obtained. ..

[0042]

Second Embodiment FIGS. 3 and 4 are circuit diagrams showing a drive circuit of a two-phase unipolar sensorless motor which is another embodiment of the present invention.

Like the first embodiment, the drive circuit of the present embodiment includes a stator that generates a magnetic field in an excited state and a rotor that obtains a rotational force by electromagnetic interaction with the stator. The present invention is applied to a fan motor in which the static stop point and the electric stop point that is the electric lock position are different, and the difference from the first embodiment is that the braking time for braking the motor without determining the rotation speed of the motor. Is the point.

That is, as shown in FIG. 3 and FIG.
By additionally connecting OR elements 28 and 29 to the respective logic circuits 3 and 4, and switching the pulse count number of one integrated circuit 30, for example, m pieces for setting the braking time,
For setting the excitation prohibition time, the braking time and the excitation prohibition time such as n are independently set through the integrated circuits 31, 32, the NOT elements 33 to 35, and the AND elements 36 to 38.

The setting signal of the braking time for braking the motor is input to the OR elements 28 and 29, while the setting signal of the excitation prohibition time is input to the AND elements 11 and 12 as in the first embodiment. Therefore, in the motor stop operation, first brake the motor for the braking time to reduce the rotation speed of the motor, then prohibit the excitation of the motor coil for the excitation prohibition time and wait for the motor to stop completely. You can restart from here.

Therefore, according to the drive circuit of the two-phase unipolar sensorless motor of this embodiment, OR is applied to the logic circuits 3 and 4.
By additionally connecting the elements 28 and 29 and setting the braking time in addition to the excitation prohibition time with one integrated circuit 30 for pulse setting, as compared with the case of waiting for the motor to naturally stop due to the braking action. Therefore, the stop time can be shortened, and the time required for restarting the motor can be further shortened.

Further, since the excitation is prohibited until the minute vibration near the stop point of the motor is stopped and the restart command is accepted after the motor is completely stopped, the reverse rotation of the motor can be prevented.

Further, as compared with the first embodiment, one integrated circuit for pulse oscillation can be used, so that cost reduction of circuit components and mutual interference can be prevented, and oscillation operation can be stabilized.

Although the invention made by the present inventor has been specifically described based on the first and second embodiments, the present invention is not limited to the above embodiments and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

For example, in the drive circuit of the above embodiment, the positive voltage sides of the coils L1 and L2 are the comparators 1 and 2.
Although the case where the negative voltage side of the coils L1 and L2 is connected to the inverting terminal has been described, the present invention is not limited to the above embodiment, and conversely the coil is connected to the inverting terminal of the comparator. It is also applicable to the circuit configuration in which the positive voltage side of is connected and the negative voltage side of the coil is connected to the non-inverting terminal.

In the above description, the case where the invention mainly made by the present inventor is applied to the drive circuit used in the fan motor, which is the field of application thereof, has been described.
The present invention is not limited to this, and is widely applicable to other two-phase unipolar sensorless motors.

[0052]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1). A pulse generation circuit that generates a one-shot pulse for a predetermined time when a start command is issued and the cycle of the motor rotation frequency is longer than a reference value, and after the start command and before the stop command. By providing a filter circuit that passes only the first one-shot pulse from the pulse generation circuit, immediate restart is performed according to the rotation frequency of the motor when a motor restart command is issued, or one-shot that has passed through the filter circuit. It is possible to reject the start command for the pulse width time of the pulse and select whether to restart after a certain time.

(2) When the motor is restarted, the braking time for braking the motor in the stopping operation of the motor and the excitation prohibition time for prohibiting the excitation of the motor coil are set in advance. The motor's rotation speed is reduced by stopping the motor, then the motor coil excitation is prohibited, the motor is stopped completely, and the motor is restarted.By doing so, the motor stop time can be shortened. The time required for restarting can be shortened.

(3) According to the above (2), since the restart command is accepted after the motor is completely stopped by prohibiting the excitation of the motor, the reverse rotation of the motor can be prevented.

(4) Due to the above (3), particularly when applied to a fan motor, since it can be rotated in the correct direction, it is possible to obtain a predetermined cooling capacity.

(5) Due to the above (1) to (3), especially in a two-phase unipolar sensorless motor having a magnetic stationary point and an electrical stationary point different from each other, even if a restart command is issued while the motor is rotating, Drive circuit for a two-phase unipolar sensorless motor that can continue rotating immediately and reduce the time required for restarting when the motor is rotating at a relatively high speed without reverse rotation. Obtainable.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a part of a drive circuit of a two-phase unipolar sensorless motor that is Embodiment 1 of the present invention.

FIG. 2 is a circuit diagram connected to FIG. 1 in the drive circuit of the two-phase unipolar sensorless motor of the first embodiment.

FIG. 3 is a circuit diagram showing a part of a drive circuit of a two-phase unipolar sensorless motor that is Embodiment 2 of the present invention.

FIG. 4 is a circuit diagram connected to FIG. 3 in the drive circuit of the two-phase unipolar sensorless motor of the second embodiment.

[Explanation of symbols]

 1, 2 Comparator 3, 4 Logic circuit 5 Pulse generation circuit 6 Filter circuit 7, 8 NOT element 9-12 AND element 13-15 Transistor 16-18 Integrated circuit 19-23 NOT element 24 Integrated circuit 25, 26 NOT element 27- 29 OR element 30-32 Integrated circuit 33-35 NOT element 36-38 AND element C1-C4 capacitor D diode L1, L2 coil R1-R16 resistance

Claims (2)

[Claims] 1. A stator comprising a stator that generates a magnetic field in an excited state and a rotor that obtains a rotational force by electromagnetic interaction with the stator, and a magnetic stationary point that is a cogging stop position and an electric lock position that is an electrical lock position. 2 which is different from the static stop
A phase unipolar sensorless motor, a pulse generation circuit that generates a one-shot pulse for a predetermined time when a start command is being issued and the period of the motor rotation frequency is longer than the reference value, and after the start command but before the stop command And a filter circuit that allows only the first one-shot pulse from the pulse generation circuit to pass through, and immediately restarts the motor according to the rotation frequency of the motor when the motor restart command is issued or passes the filter circuit. A drive circuit for a two-phase unipolar sensorless motor, characterized in that a start command is rejected for a pulse width time of a one-shot pulse, and whether to restart after a certain time is selected. 2. When restarting the motor, a braking time for braking the motor in a motor stop operation and an excitation prohibition time for prohibiting the excitation of the motor coil are set in advance, and the motor is braked first. 2. The driving of a two-phase unipolar sensorless motor according to claim 1, wherein the number of revolutions of the motor is reduced, then the excitation of the motor coil is prohibited, the motor is completely stopped, and then restarted. circuit.