JPS62233096A - Driving system for stepping motor - Google Patents

Abstract

PURPOSE:To allow a motor to perform a step drive at the speed of one half of the pulse speed and to reduce the vibration, by setting the halfway of the phase in short-circuited state in a specified time only in starting and finishing feeding the current to each phase. CONSTITUTION:An exciting change-over section 6 turns ON the exciting signal to the bases of each transistor 21... 24 based on the input pulse. A transistor 7 is connected to the centre tap of a coil group and the other end of the output is connected to the negative side of DC power source 5. A timer circuit 8 is connected to the base of a transistor 7 for a specified period only in starting and finishing feeding the current to each phase l, and short-circuits the halfway of a coil group comprising a phase 1.

Description

[Detailed description of the invention] a. Industrial application field The present invention relates to a stepping motor driving method.

b. Conventional technology The excitation method for stepping motors is called bipolar operation, in which a switching element is connected in a pre-Fuji format so that the monofilament coil can be energized in either direction, and the polarity of the current flowing through the coil is alternated. There is a method.

FIG. 6 shows an excitation circuit for only one phase in a multi-phase stepping motor drive system employing a bipolar excitation system.

This connects four transistors T+-...T4 to the coil constituting phase 100 by bridge connection.
An excitation switching unit 101 that provides an excitation signal is connected to each base of the transistor T#.

On the other hand, bridge-connected transistor ↑1−・−・T4
A current control unit 102 is provided on the input side of the power supply, and this current control unit 102 controls the power supply current while comparing the current command and the current detected by the current detection unit 103.

Next, Fig. 7 (al, (bl, (cl, ()
The explanation will be based on the timing chart of di and tel.

FIG. 7 (al indicates an input pulse, and this pulse causes the excitation switching unit 101 to give an excitation signal as shown in FIG. 7 to each phase 100). On the other hand, since a current based on a current command as shown in FIG. 7 fcl flows from the current control unit 102 in the Brifuji circuit, a current as shown in FIG. 7 tdl flows in each phase 100 of the motor winding. become.

In this way, the motor is driven in 1/4 steps as shown in FIG. 7 (el) by the current flowing in the human phase B.

Problems to be Solved by the C0 Invention In this way, by giving a narrow current command to the 11J1 rotation, it becomes possible to perform a step operation by minute angles.

However, according to such a system, it is necessary to control the current on the power supply side that passes through the excitation circuit, making the control circuit complicated and expensive. Furthermore, the number of pulses of the pulse signal that determines the step angle must be increased accordingly.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a driving method for a stevening motor that allows step operation at a minute angle using only an excitation signal while keeping the power supply current constant.

d. Means for Solving the Problems The present invention provides a method for driving a multi-phase stamping motor using a bipolar excitation method. The reason is that

e. Effect: At the start and end of energization to each phase, the phase is short-circuited for a certain period of time to reduce the torque by half. As a result, the step operation is performed at approximately half the normal step angle, resulting in a step MJ movement of 1/4 step.

f. Examples The present invention will now be described in detail with reference to the illustrated embodiments.

FIG. 1 is a circuit diagram showing a driving method of a stepping motor in which a monofilar winding bipolar excitation method is adopted for the windings and excitation circuit of the multiphase stepping motor.

The drawing shows only one phase of a two-phase stepping motor, and ▪ is a phase composed of a coil group.

21...24 is the 4 bridge connected to this phase 1.
This transistor functions as a switching element. Reference numeral 3 denotes a constant current circuit connected to the input side of the prefuji circuit 4, and this is connected to the anode side of the DC power supply 5.

Reference numeral 6 denotes an excitation switching unit that supplies an excitation signal to the base of each transistor 21, . . . , 24 based on an input pulse. It turns on and off.

Reference numeral 7 designates a transistor whose output end is connected to a center tap located approximately in the middle of the phase 1, that is, approximately in the middle of the coil group, and whose other output end is connected to the negative side of the DC current R5. functions as a short-circuit switching element.

Reference numeral 8 denotes a timer circuit connected to the base of the transistor 7, which detects the pulse signal and operates the transistor 7 for a certain period of time at the start and end of energization for each phase 1, thereby configuring phase 1. This short-circuits the middle of the coil group.

Next, the operation of the above-mentioned stamping motor drive system will be explained with reference to the time chart shown in FIG.

First, basically, the excitation switching unit 6 operates the transistors 2□2, . . . based on the pulse train shown in FIG. , t-0111,
Next, count the number of pulses and turn off transistors 2+ and 24.
F, transistors 2□, 2. Turn on. As a result, current flows alternately on the left and right sides of phase 1, and torque is generated by the magnetic field generated between the currents flowing in the other phases, and step drive at a constant angle is performed.

At this time, if the two phases 1 are the A phase and the B phase, the timer circuit 8 is activated to turn on the transistor 7 for a certain period of time t at the start and end of the energization of the human phase and the B phase. As a result, the A-phase and B-phase coil groups are short-circuited at their intermediate points, and the number of turns of the coils is reduced to approximately 1/2, thereby reducing the torque by half. For example, in Fig. 2d, the position of the Peltor 14 normally shifts to the position of vector 0 with the next pulse, but at this time, the midpoint of the A phase is short-circuited by the timer circuit 8 for one hour, so the A phase Torque 1/
2 and the B-phase torque l, the vector 15 is obtained as shown in Figure 3.
will be moved to the position of That is, the rotation of the motor is temporarily stopped at approximately 1/2 of 45 degrees, thereby substantially reducing the step angle. In this way, Figure 2+a
+, step drive is performed at substantially the same step angle as in the conventional case. As shown in FIG. 4, by setting the number of turns at m:n so that the step angles at the short-circuit positions are equal, the torque can be adjusted to drive the step angle at a constant value. Note that in this case, one end of transistor 71 is connected to the connection point of transistor 22.2#. Furthermore, as shown in FIG. 5, the same effect can be obtained by connecting the transistor 7□ between the phase 1 and the anode side of the power source.

g. Effects of the Invention As described above, according to the present invention, in the drive method of a multiphase stepping motor using the bipolar excitation method,
By short-circuiting the middle of each phase for a certain period of time at the start and end of energization to each phase, it is possible to perform step drive at a speed of 172 pulse speeds.
Vibration of the stepping motor can be reduced. Furthermore, since the circuit configuration can be simplified compared to the conventional one, the cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the stepping motor driving method according to the present invention, FIG. 2 is a timing chart showing the stepping motor driving method according to the present invention, and FIG.
2 is a vector representation of the operation shown in FIG. 2, FIGS. 4 and 5 are circuit diagrams showing other embodiments of the present invention, and FIG. 6 is a circuit diagram showing a conventional stepping motor drive system. FIG. 7 is a timing chart showing the driving method of the stepping motor shown in FIG. 6. 130. Phase, 21...-Track 2O, 7...Transistor, 3...Constant current circuit, 4...Bridge circuit, 5...DC power supply, 6...Excitation switching unit, 8...・Timer circuit. Patent applicant Oriental Motor Co., Ltd.] (2 others) Whistle 1, 2, 3, 4, 5, 6, 7, 7

Claims (3)

[Claims] (1) A stepping motor drive method using a bipolar excitation method that is characterized by short-circuiting the middle of each phase for a certain period of time at the start and end of energization of each phase. . (2) The stepping motor driving method according to claim (1), characterized in that a switching element for shorting is connected between each phase and the positive side or negative side of the power supply. (3) The stepping motor driving method according to claim (2), further comprising a timer circuit that operates the switching element at the start and end of energization of the phase.