JPS61262099A - Stepping motor drive circuit - Google Patents

Abstract

PURPOSE:To obtain no vibration of a rotor at low speed rotation time and a necessary output torque at high speed rotation time by supplying a drive voltage of the optimum amplitude in response to the rotational speed. CONSTITUTION:A pulse signal 21 for designating the rotational speed of a stepping motor is transmitted to a drive 4 from a controller 3, a variable voltage command signal 22 of the frequency corresponding to the frequency of the signal 21 is simultaneously transmitted to a voltage converter 6, the amplifier 8 of the converter 6 amplifies it to apply it to the base of a transistor 9. Thus, the drive voltage becomes that corresponding to the frequency of a variable voltage command signal 22, and is supplied to the driver 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stepping motor drive circuit, and more particularly to a stepping motor drive circuit that uses a constant voltage to drive a stepping motor.

[Conventional technology]

A conventional stepping motor drive circuit that supplies a constant voltage to drive a stepping motor uses 8
It has a configuration as shown in Fig. g2 as an example. In other words, the pulse signal 21 sent from the control section 13 to the driver circuit 14 is transmitted to the constant voltage power supply 7 in the driver circuit 14.
is supplied from the power supply voltage Vc and is amplified by the power supply voltage Vc to the excitation winding ili! of the stepping motor 5. 5a to drive the rotational movement of the stepping motor 5. The relationship between the stepping motor 50 rotation speed and the output torque at this time exhibits a characteristic as shown in FIG. That is, when the driving voltage is constant and the rotational speed is low, the output torque is quite large, but when the rotational speed exceeds a certain value, the output torque rapidly decreases. Therefore, if the stepping motor is to rotate at high speed and high output torque is required, the driving voltage of the driver circuit must be set to a considerably high voltage.

On the other hand, when a high driving voltage is supplied to a stepping motor to cause it to rotate at a low speed, the stepping motor rotor vibrates as shown in Figure 5, and it takes a considerable amount of time for the stepping motor to stably remain at a given position. If the drive voltage is set to a low voltage in order to avoid such rotor vibration, the necessary output torque cannot be obtained at high speed rotation as described above.

In this way, the conventional stepping motor drive voltage control circuit can only supply a constant 11L source voltage to the driver circuit, so when the stepping motor needs to be used at a rotation speed of more than 200 Hz.

There are two disadvantages: either it is not possible to obtain a sufficient output torque when rotating at high speeds, or the rotor of the stepping motor vibrates when rotating at low speeds, requiring a considerable amount of time to come to a stable standstill. , they are disappointed in the fact that they cannot satisfy both parties.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is to eliminate the drawbacks of the conventional stepping motor drive circuit as described above.Therefore, it is an object of the present invention to eliminate all of the above drawbacks and to To provide a stepping motor drive circuit which can obtain sufficient output torque and can quickly and stably bring the rotor to a standstill without vibration even during low-speed rotation.

[Problem 't-Means for solving]

The stepping motor drive circuit of the present invention includes a control section that sends out a pulse signal with a frequency corresponding to the rotational speed of the stepping motor, a constant voltage power source that supplies a power supply voltage for driving the stepping motor, and a control section that sends out a pulse signal with a frequency corresponding to the rotation speed of the stepping motor. and a driver circuit that receives the power supply voltage and sends a drive pulse signal to a drive winding of the stepping motor, wherein the control section is provided between the constant voltage power supply and the driver circuit. A pulse t- of a frequency corresponding to the frequency of the pulse signal from
The power supply voltage converter circuit is configured to include a voltage conversion circuit that receives a variable voltage command signal having a predetermined value, converts the power supply voltage into a drive voltage of a predetermined value, and outputs the drive voltage.

〔Example〕

The present invention will now be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

As shown in the figure, the source voltage of the constant voltage circuit 70'# which supplies a constant power supply voltage VC is manually inputted to the variable voltage circuit 6.
The output voltage ■1 of the voltage conversion circuit 6 is input to the driver circuit w64. The control unit 3 sends a pulse signal 2 to the driver circuit 3.
1, and also sends out a variable voltage command signal 22 having a frequency corresponding to the frequency of the pulse signal 210 to the voltage conversion circuit 6. The driver circuit 4 receives the pulse signal 2 from the control section 3.
1 and the output voltage (drive voltage) Vt of the conversion circuit 6 are input, and a drive pulse signal 23 of a predetermined voltage is sent to the excitation winding 5a of the stepping motor 5 to drive the stepping motor 5 at a predetermined rotation speed.

The voltage conversion circuit 6 includes an amplifier circuit 8 that inputs the variable voltage command signal 22 sent from the control unit 3, amplifies it, and outputs it, and a power supply voltage Vc from the constant voltage power supply 7 through the transistor 9t. A transformer 10 connected to the secondary winding and rectified by the output sound capacitor C and diode D from the secondary winding to output the output voltage
The transistor 9 has an output connected to its base, and a transistor 9 whose collector and emitter connect one terminal of the constant voltage power supply 7 and one terminal of the primary winding of the transformer 10.

The stepping motor drive circuit configured as described above simultaneously responds to the frequency of the pulse signal 210 when the control unit 3 sends the pulse signal 21 specifying the number of rotations of the stepping motor to the driver circuit 4. Since the variable voltage command signal 22 having the same frequency is sent to the voltage conversion circuit 6, the amplifier circuit 8 of the voltage conversion circuit 6 amplifies it and sends it to the transistor 90 pace. Therefore, since an alternating current synchronized with the pulse period of the variable voltage command signal 22 flows through the primary winding of the transformer 10, an induced current proportional to the pulse period of the variable voltage command signal 22 is generated in the secondary winding. Therefore, the rectified secondary voltage (drive voltage) {circle around (2)} is supplied to the driver circuit 4 as a voltage corresponding to the frequency of the variable voltage command signal 220.

In order to specify the stepping motor 50 rotation speed, the control section 3 sends a pulse signal 21 with a frequency corresponding to the specified rotation speed to the driver circuit 4, but at this time, the frequency of the pulse signal 210, that is, the stepping motor 7- A variable voltage command signal 22 with a predetermined frequency is sent to the voltage conversion circuit 6 so that a drive voltage Vt determined in accordance with the rotational speed of 5 is obtained. The relationship between the pulse signal 210 frequency and the variable 1 pressure command signal, that is, the relationship between the rotation speed of the stepping motor and the drive voltage, is set according to the design conditions of the device that uses this stepping motor, and is stored in a read-only memory, etc. It is built into the control unit.

FIG. 3 is a graph showing an example of the relationship between the rotation speed and drive voltage of the stepping motor when driven according to the embodiment shown in FIG.
5 is set, and when the rotation speed is low, the voltage is low so that vibrations of the stepping motor rotor do not occur, and when the rotation speed is high, the voltage is high so that a light output torque can be obtained.

FIG. 4 is a chart showing the relationship between the rotation speed and output torque of the stepping motor using the drive voltage set as shown in FIG. 3 as a parameter. As shown in the figure, when the drive voltage is constant, the output torque 7 decreases as the rotation increases, and when the rotation speed reaches a certain value, it tends to decrease rapidly, but as the drive voltage increases, the output torque 7 decreases as the rotation increases. As the output torque increases, the rotational speed at which it starts to drop rapidly also increases. Therefore, when the stepping tanabata rotation speed is set to l to r5, the output torque FiTl to T5 can be obtained by setting the drive voltage at that time to 1 to V11. It can be used as a characteristic.

〔Effect of the invention〕

As explained in detail above, the stepping motor drive circuit of the present invention can supply a drive voltage of an optimal magnitude corresponding to the rotation speed of the stepping motor.
By using the stepping motor drive circuit of the present invention, in a device that needs to drive a stepping motor at multiple rotational speeds, there is no vibration of the rotor during low-speed rotation, and the necessary output is achieved during high-speed rotation. This has the effect of providing torque.

[Brief Description of the Drawings] Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram showing an example of a conventional stepping motor drive circuit, and Fig. 3 is an embodiment t of Fig. 1. FIG. 4 is a graph showing the relationship between the rotation speed of the stepping motor and the driving voltage when driven. FIG. 4 is a graph showing the relationship between the stepping motor rotation speed and output torque using the driving voltage as a parameter.
The figure is a graph showing the movement of the rotor of a stepping motor. In the figure, C: Capacitor, D: Diode, VC: Power supply voltage, ■[... Drive voltage. Agent: Susumu Uchihara, patent attorney. ￥-22 Kokyoku Shusuke 3 Kaita#, number

Claims (1)

[Claims] a control unit that sends out a pulse signal with a frequency corresponding to the number of rotations of the stepping motor; a constant voltage power supply that supplies a power supply voltage for driving the stepping motor; A stepping motor drive circuit including a driver circuit that sends a drive pulse signal to a drive winding of a stepping motor,
A variable voltage command signal having a pulse having a frequency corresponding to the frequency of the pulse signal is inputted from the control unit provided between the constant voltage power supply and the driver circuit to adjust the power supply voltage to a predetermined value of the drive voltage. A stepping motor drive circuit comprising a voltage conversion circuit that converts and outputs voltage.