JPS6020795A - Driving method of stepping motor - Google Patents

Abstract

PURPOSE:To minimize the power consumption by entirely interrupting the energization of a coil during stopping period. CONSTITUTION:Drive pulses phiA, phiB, phiC, phiD are sequentially displaced in phase, applied to coils L1, L2, L3, L4 to rotate the rotor as prescribed. All coils are interrupted at the stopping time. The applied state of the drive pulse of the step at the stopping time, i.e., the pulses phiD, phiA are, as shown, applied at the restarting time, and it becomes the state that the pulses phiB, phiC are interrupted. Thus, it is effectively returned to the state that the rotor R is stopped, the prescribed rotation is then applied, thereby providing an accurate operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a stepping motor that minimizes power consumption.

In conventional stepping motors, even when stopped, the coils on the stator poles must be energized to attract and hold the rotor poles in place using the magnetic force of the stator poles, otherwise the rotor position will deviate to an arbitrary position when restarted. This caused a problem in that the coil was energized even when the motor was stopped (this resulted in high power consumption and the stepping motor generated heat, shortening its life and reducing performance).

The present invention eliminates the above-mentioned drawbacks, minimizes power consumption by cutting off current to the coil when the stepping motor is stopped, and furthermore positions the rotor at the correct position i (i') when the stepping motor is restarted. The purpose of the present invention is to provide a method for driving a motor.

The driving method according to the present invention is characterized in that the rotor is driven by applying a predetermined sequence of driving pulses generated by the power supply voltage to the coils provided at the multiple poles of the stator that cooperate with the multiple poles of the stator. In a method of driving a stepping motor that rotates one step at a time in a predetermined direction, the power supply voltage is cut off when the rotor is stopped, and the power supply voltage is reapplied when the rotor is restarted, thereby changing the state given to each coil at the time of the stop. The present invention is capable of minimizing power consumption and ensuring an accurate restart position of the rotor by applying a drive pulse of 1000 Ω.

By doing so, when the stepping motor is stopped, the current to the coil is completely stopped, and power consumption can be minimized. In this case, the poles of the rotor cannot be held in the predetermined suction and holding position because they get caught in the stator poles, but when restarting, the rotor is attracted to the same position as when stopped by giving the coil a drive pulse in the same state as the step at the time of stop. A predetermined rotation can then be applied to ensure accurate operation.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of a stepping motor driven by the present invention, with coils Ll, L2, L3, . L4
．． Salient pole P1. having LL, L2... P
2.

P3. P4. A stake S with PL, P2..., and a pole Pi, P2. The rotor R consists of a large number of gear-shaped poles Pf that cooperate with the rotor R, and the arrangement interval of the poles P of the rotor R is as shown in FIG. When a driving pulse is applied to the poles 33 and P4, a magnetic circuit is formed between the poles P of the rotor R located between these poles, and the rotor R is held in the step position shown in FIG. When a driving pulse is applied to the coils L4 and Ll as shown in Figure (B), the rotor R is rotated so that a magnetic circuit passing through the pole P of the rotor R between the poles P4 and P is formed. It is held at the step position shown in Figure 1 (B). In this way, by appropriately selecting the energization to the coil, the rotor RIc can be rotated by a desired number of steps. When the current to the coil is cut off in this state, the pole P of the rotor R will be the pole P4 or P of the tilted stator S.
The position of the rotor R becomes unstable because it moves freely to a position opposite to the rotor R.

Conventionally, in order to prevent the rotor position from becoming unstable when stopped, the coils were energized even when stopped.

An example of a conventional coil energization control circuit is shown in FIG. D3
．． In combination with D4, transistors Tr1 + Tr2
+ Tr3 + Tr4 VC connected respectively /l/L L, L2, L3 + L4
K given, transistor Tr1゜Tr2 + Tr3 +
A command signal is given to each Tr4 from a command circuit (not shown) to rotate the rotor as desired, and the coils LL, L2, etc. are selectively energized, and when stopped, the state of the drive pulse of the step at that time is maintained. It's Sazerono.

FIG. 3 shows the application state of such driving pulses. That is, each coil Ll.

L2. L3. Drive pulses φA, φB, φ for L4
C1φD are pulses φA each having a predetermined phase difference Δφ.

Rotate the rotor R in a predetermined direction with a delay in the order of φB... If the phase shift of each pulse is reversed, rotation will occur in the opposite direction.

When the rotor R is stopped at and X, the state of the pulses of the step at that time, that is, in FIG. 3, the pulses φA and φB are kept in the energized state, and the pulses φC2φD are kept in the cut-off state. Therefore, the rotor R is stopped with the pole P of the rotor R being attracted and held between the poles Pi and P2. At the time of restart, the state is shifted to the next step pulse application state. In this way, even during the stop period, electricity continues to be applied to one of the coils, which is extremely uneconomical.

Figure 4 shows that a voltage drop circuit VD consisting of a Zener diode and a transistor is added to the constant voltage circuit S in order to reduce the amount of continuous current flow during the stop period, and during the stop period the transistor operates as shown in Figure 5. This reduces power consumption by lowering the voltage applied to the coil. However, although this method generates less heat, it requires two power supply systems and is complicated.

As described above, in any case, in the conventional rotor, it is necessary to supply electricity even during the stop period when the electric power required for rotating the rotor is not required, which is extremely uneconomical.

In order to eliminate the above-mentioned drawbacks, the present invention is designed to completely cut off the current to the coil during the stop period.

That is, as shown in FIG. 6, the driving pulse φA.

φB, φC2φD are connected to each coil Ll, L2 . L3. L4 is applied to give a predetermined rotation of the rotor, but when the rotor is stopped, power to all coils is cut off. At the time of restart, the driving pulses of the step at the time of stop are applied, that is, in FIG. 6, the pulses φD and φA are applied, and the pulses φB and φC are cut off. This ensures that the rotor R is returned to the state it was in when it stopped, and is then given a predetermined rotation to ensure accurate operation.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the operating mode of a stepping motor suitable for use in the present invention. Figure 2 shows conventional coil energization! ! The circuit diagram which shows one example of a control circuit. FIG. 3 is a diagram showing the driving pulse application state by the circuit of FIG. 2; FIG. 4 is a circuit diagram showing a modification of FIG. 2. FIG. 5 is a diagram showing how the operating voltage changes according to the circuit of FIG. 4. FIG. 6 is a diagram showing the driving pulse application state according to the stepping motor driving method of the present invention. FIG. 7 is a drawing showing the position of the rotor at the time of restart according to the present invention. φA, φB, φC1φD..., drive pulse Ll,
L2. L3. L4.・・・ Coil P・・・・・・
Rotor poles Pl, P2. P3. P4... 7f-1s(r) pole R... Loaf S... Stator patent applicant Kobal Co., Ltd.

Claims (1)

[Claims] A stepping motor is driven by rotating the rotor one step at a time in a predetermined direction by applying drive pulses in a predetermined sequence generated by a power supply voltage to the coils provided at the many poles of the stator that cooperate with the many poles of the rotor. In this method, when the rotor is stopped, the power supply voltage f is cut off, and when the rotor is restarted, the power supply voltage f is applied again, and power consumption is reduced by applying the drive pulse that was applied to each coil during the step when the rotor was stopped. A method for driving a stepping motor, characterized in that an accurate restart position of a rotor can be ensured with minimal effort.