JPH05207796A - Step motor controller - Google Patents

Abstract

PURPOSE:To realize the drive control of a step motor over a wide speed range by providing a distribution circuit generating a phase excitation pulse signal for determining the exciting order of the windings of step motor with means for producing different voltage signals depending on the frequency of input pulse signal. CONSTITUTION:In case of low speed operation, input pulse 41 has low frequency and a frequency/voltage converting circuit 16 produces a low output voltage 164 and thereby the currents 43, 44, 45 to be fed from an exciting circuit 12 to the winding of a step motor 30 have low level. Consequently, the motor 30 having low torque rotates smoothly. In case of high speed rotation, the input pulse 41 has high frequency and the frequency/voltage converting circuit 16 produces a high output voltage 164 and thereby the currents 43, 44, 45 have high level. Consequently, the motor 30 having high torque rotates without causing step-out due to the deficiency of torque. According to the constitution, the drive control of the step motor can be realized over a wide speed range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stepping motor control device, and more particularly to a stepping motor control device which changes an electric current flowing through a winding of the stepping motor in response to a change of a rotation speed of the stepping motor to generate an appropriate torque. ..

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a stepping motor control device 20 has phase excitation pulse signals 66, 67 and 68 for determining the winding excitation sequence of a stepping motor 30 according to an input pulse 61 sent from a host device. And a exciting circuit 22 for outputting winding currents (exciting currents) 63, 64 and 65 to the motor 30 in accordance with phase exciting pulse signals 66, 67 and 68 from the distributing circuit 21. .. In addition, this control device uses a motor 30
Of the reference voltage generating circuit 23 for generating a reference voltage 69 for determining the value of the current flowing through the winding of the motor, and a constant voltage control circuit for controlling the exciting circuit 22 to supply a current proportional to the reference voltage 69 to the winding of the motor 30. And a current circuit 24.

The operation of this conventional example will be described with reference to FIGS. FIG. 6 shows an operation timing chart of the one-phase excitation method, in which the stepping motor 30 uses the stator winding A,
The input pulse 61 input to the distribution circuit 21, the output current 62 of the constant current circuit 24, and the A phase input to each phase winding of the stepping motor 30 are assumed to have B and C phases (not shown). , B-phase and C-phase winding currents 63, 64 and 65 are shown in time series. The heights of the current waveforms 62, 63, 64 and 65 represent current values. Every time the input pulse 61 is input to the distribution circuit 21, the distribution circuit 21 outputs the phase excitation pulse signals 66, 67 and 68 to the excitation circuit 22. This phase excitation pulse signal 66,
Although not shown, 67 and 68 are pulses in phase with the winding currents 63, 64 and 65. The excitation circuit 22 has a current value corresponding to the constant current 62 from the constant current circuit 24, and the winding current 6 corresponding to the phase excitation pulse signals 66, 67 and 68.
3, 64 and 65 are sent to the stator winding of the stepping motor 30 in the order of A phase → B phase → C phase. Input pulse 61
The value of the output current 62 of the constant current circuit 24 is constant even at the time T when the rotation speed of the stepping motor 30 becomes faster by increasing the frequency of the winding current 63 of each phase, which is the output of the excitation circuit 22. , 64 and 65 are constant.

[0004]

In the drive control of the stepping motor according to the above-mentioned prior art, constant torque drive is performed because the stepper motor is driven by a constant current set by the reference voltage, and if the variable speed range is widened, the torque is reduced in the low speed range. Is too large, the motor does not rotate smoothly, and the torque is small in the high-speed range, so there is a problem that the motor does not run normally due to step out.

[0005]

A stepping motor control apparatus of the present invention generates a phase excitation pulse signal that determines the winding excitation sequence of a stepping motor in response to an input first pulse signal. Means for supplying an exciting current to the winding of the motor in response to the phase excitation pulse signal from the first means, and a first means that varies according to the frequency of the first pulse signal. Means for outputting the voltage signal of No. 3, fourth means for generating the second voltage signal for determining the reference value of the exciting current, the first voltage signal and the second voltage signal, Fifth means for controlling the second means so as to supply the exciting current to the winding of the motor in proportion to the sum of the above.

[0006]

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

Referring to FIG. 1 showing an embodiment of the present invention, a stepping motor control device 10 determines a phase excitation pulse signal for determining the winding excitation sequence of a stepping motor 30 according to an input pulse 41 sent from a host device. Four
Distribution circuit 11 for generating 6, 47 and 48, and excitation circuit 12 for outputting winding currents 43, 44 and 45 to motor 30 in accordance with phase excitation pulse signals 46, 47 and 48 from distribution circuit 11, The frequency / voltage conversion circuit 16 converts the frequency of the input pulse 41 into a voltage and outputs the voltage. Further, the control device 10 includes a reference voltage generating circuit 13 for generating a reference voltage for determining a reference of a current value flowing through the winding of the motor 30, an output voltage of the frequency / voltage converting circuit 16, and a reference voltage generating circuit 13. It has an adding circuit 15 that outputs a voltage that is the sum of the output voltage, and a constant current circuit 14 that controls the exciting circuit 12 to supply a current proportional to this voltage to the winding of the motor 30.

As shown in detail in FIGS. 3 and 4, the frequency / voltage conversion circuit 16 includes a monostable multivibrator circuit 161 which outputs a pulse 163 having a constant width according to an input pulse 41, and the monostable multivibrator circuit 161.
Output pulse 163 is smoothed and output as voltage 164. The output voltage 164 of the smoothing circuit 162 is the monostable multivibrator circuit 161.
The voltage value is in proportion to the frequency of the output pulse 163 of.
Therefore, the output voltage 164 of the smoothing circuit 162 becomes higher from the time T when the rotation speed of the stepping motor 30 becomes faster.

The operation of this embodiment will be described with reference to FIGS. 1, 2, 3, and 4. FIG. 2 shows an operation timing chart of the one-phase excitation method. It is assumed that the stepping motor 30 has stator windings A, B, and C phases (not shown), and an input pulse 41 input to the distribution circuit 11 and a constant pulse. The output current 42 of the current circuit 14 and the stepping motor 30
The A-phase, B-phase, and C-phase winding currents 43, 44, and 45 input to the windings of each phase are shown in time series. Also,
The heights of the signals 42, 43, 44 and 45 represent current values. Each time the input pulse 41 is input to the distribution circuit 11, the distribution circuit 11 causes the phase excitation pulse signals 46, 47 and 48 to be transmitted.
Is output to the excitation circuit 12. This phase excitation pulse signal 4
6, 47 and 48 are not shown, but winding currents 43, 4
4 and 45 are in-phase pulses. The excitation circuit 12 supplies the winding currents 43, 44 and 45 corresponding to the phase excitation pulse signals 46, 47 and 48 with the current value corresponding to the constant current 42 from the constant current circuit 14 to the stator winding of the stepping motor 30. To A phase, B phase, and C phase in this order. Input pulse 4
The value of the output current 42 of the constant current circuit 14 becomes higher from the time T when the rotation speed of the stepping motor 30 becomes faster by increasing the frequency of 1, and the winding current 43 of each phase which is the output of the excitation circuit 12 is increased. , 44 and 45 are constant current circuits 14
Corresponding to the output current value of. Therefore, in the case of low speed operation, the output voltage 164 of the frequency / voltage conversion circuit 16 becomes small because the frequency of the input pulse 41 is low, and the currents 43 and 44 supplied from the excitation circuit 12 to the windings of the motor 30.
And the values of 45 are small. As a result, the motor 30 having a small torque smoothly rotates. On the contrary, in high-speed operation, the frequency of the input pulse 41 is high, so
The value of the output voltage 164 of 6 becomes large, and the winding current 43,
The values of 44 and 45 are large. As a result, the motor 30 having a large torque rotates without losing step due to insufficient torque.

In the above-described embodiment, the stepping motor 30 has three stator windings A, B and C, but the number of stator windings need not be limited to three. Also, the excitation method of the stator winding has been exemplified by the one-phase excitation method in which the phases are switched one by one, but other excitation methods such as a two-phase excitation method can be similarly applied.

[0011]

As described above, according to the present invention,
A third means for outputting a first voltage signal different depending on the frequency of the first pulse signal input to the first means for generating a phase excitation pulse signal for determining the winding excitation sequence of the stepping motor is provided. With this provision, the exciting current of the winding changes according to the rotation speed of the stepping motor to generate an appropriate torque, so that the drive control of the stepping motor can be performed over a wide range of speeds.

[Brief description of drawings]

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

FIG. 2 is an operation timing chart of an embodiment of the present invention.

FIG. 3 is a configuration diagram of the frequency / voltage conversion circuit shown in FIG. 1.

4 is an operation timing chart of the frequency / voltage conversion circuit shown in FIG.

FIG. 5 is a configuration diagram of a conventional example.

FIG. 6 is an operation timing chart of the conventional example shown in FIG.

[Explanation of symbols]

 10 Stepping Motor Control Device 11 Distribution Circuit 12 Excitation Circuit 13 Reference Voltage Generation Circuit 14 Constant Current Circuit 15 Addition Circuit 16 Frequency / Voltage Conversion Circuit 30 Stepping Motor

Claims (3)

[Claims] 1. A first means for generating a phase excitation pulse signal for determining a winding excitation sequence of a stepping motor in response to an input first pulse signal, and the phase from the first means. Second means for supplying an exciting current to the winding of the motor in response to an exciting pulse signal, and third means for outputting a different first voltage signal depending on the frequency of the first pulse signal, Second for determining the reference value of exciting current
Means for generating a voltage signal, and the second means for supplying the exciting current proportional to the sum of the first voltage signal and the second voltage signal to the winding of the motor. And a fifth means for controlling the stepping motor control device. 2. A means for the third means to generate a second pulse signal of a predetermined time width in synchronization with the first pulse signal, and a smoothing of the second pulse signal from this means. 2. The stepping motor control device according to claim 1, further comprising: means for generating the first voltage signal. 3. A third voltage signal obtained by adding the first voltage signal from the third means and the second voltage signal from the fourth means is supplied to the fifth means. The stepping motor control device according to claim 1, further comprising a sixth means.