JPS59181994A - Drive control system of step motor - Google Patents

Abstract

PURPOSE:To reduce the size of a step motor by eliminating a current flowed to a phase control transistor at the phase switching time by providing a current/ voltage control transistor, thereby reducing the withstand voltage of the transistor. CONSTITUTION:A current is interrupted by a current/voltage control transitor TR0 slightly before interrupting a current flowed to any two of drive coils C1- C4 by phase control transistors TR1-TR4. Then, a flyback voltage generated across the drive coil is erased by a current flowed through the drive coil, conducted phase control transistor and a flyback diode D. After the flyback voltage is erased, the phase control transistor is interrupted.

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a drive control method for a step motor, in particular, a method for controlling the drive of a step motor, in particular, a method for controlling a step motor by applying a power supply voltage between one pole of the power supply and a common terminal of the drive coil of the step motor. This invention relates to a step motor control method that includes a control means for controlling the drive coil and a flybank voltage erasing means between the common terminal of the drive coil and the other pole of the power supply. As a drive control method for a step motor, there is one shown in FIG. 1, for example. Its driving method uses a predetermined phase current Φ1. Φ2. Φ3. In order to supply Φ4 to each driving coil CI, C2, C'3°C4 of the step motor, each driving coil C1, C2°C3, C4 and a phase control transistor TR1.

TR2, TR3, and TR4 are connected in series and connected in parallel to the electric valve, respectively, and the phase control transistors TRI and T are connected in a predetermined order as shown in FIG. 1(B).
The step motor was driven by 0N10FF control of R2, TR3, and TR4. During this drive, the fly bank voltage erasing diode DI generated across each drive coil C1, C2, C3, C4,
D2, D3.

D4 was connected to both ends of each drive coil, respectively. For this purpose, each phase control transistor TRI.

TR2, TR3, and TR4 are required to have high withstand voltage, and flyback voltage erasing diodes D1, D2, and
3 and D4 were required for each coil. Further, in order to reduce the power consumed by each drive coil and each phase control transistor when the step motor is stopped, it is necessary to control a plurality of the above-mentioned phase control transistors even when performing chop control. In addition, the control circuit is complicated, and in two-phase and three-phase excitation systems, there is a risk that the stopping torque and stopping position may vary due to unbalanced chopper current due to variations in transistor characteristics.

(Objective and Structure of the Invention The present invention provides a braking means for controlling a power supply voltage of 0N10FF between 10,000 poles of a power supply and a common terminal of a drive coil of a step motor, It is an object of the present invention to solve the above problems by providing a flyback voltage erasing means between the poles of the stellaf0 motor of the present invention. The method is to drive a Stellaf 0 motor, which has a switching means for passing a current of a predetermined phase through a plurality of drive coils, and a flyback output and pressure elimination means.The voltage supplied from the power supply to the step motor is 0N10.
FF 1liil J a switching means for flowing a current of a constant phase; and a flyback voltage erasing means for erasing a flyback voltage generated in the drive coil between a common connection point of each of the switching means and a common voltage terminal of the plurality of drive coils. It is characterized by having the following.

D) Examples of the invention The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an example of a step motor driving method according to the present invention. In Figure 2 (4), C1°C2, C3
, C4 are step motor drive coils, Vl, V2 . V
3. V4 is a phase control signal voltage, Φ1. Φ2. Φ3. Φ
4 is each phase control signal voltage V1. ．． V2, ■3, V4
The current flowing through each drive coil when is at H level, ■0
is the power supply voltage control signal voltage, Φ0 is the current supplied to the step motor when the power supply voltage control signal voltage 0 is at L level, and D[indicates a diode for erasing flyback voltage.

First, we will explain the case of rotating a two-phase excitation type step motor.O To rotate the rotor of the step motor shown in Figure 1 (5) from the position ■ to the position @, the second
As shown in Figure CB), the phase control signal voltage V'4. V
From the state where l is at H level (phase control currents Φ4 and Φ1 are flowing), -; first, the phase control signal voltage V4 is set to L level (only Φl is flowing), and the rotor )'s drink Ri rotates. Next, when the phase control signal voltage V2 is set to H level (ψJ Φ2 is flowing), the rotor is @
Rotate to the position. By switching the H level of the phase control signal voltage from V4 vi to VIV2 as described above, the rotor rotates 90 degrees from position ■ to position @.

Similarly, the H level of the phase control signal voltage is set to Vl and V2.
From V2. V3, V2. V3 to V3. By sequentially switching to V4..., the rotor rotates. By the way, the drive coils CI, C2, C3, of the step motor
C4 has an inductance, and currents Φ1゜Φ2 . Φ3. Φ4 is a phase control transistor TRI.

If TR2, TR3, and TR4 are cut off, a large back electromotive force, ie, a flyback voltage, is generated, and the phase control transistors TRI, TR2, TR3 and TR4 are damaged. For this reason, conventionally, as shown in Figure 1 (Q),
A flyback voltage erasing diode was connected to both ends of each drive coil, and a current was passed through the diode 1' to prevent the flyback voltage from occurring. However, in the step motor disease control method 1 according to the present invention, it is not necessary to connect the flyback voltage erasing diodes to both ends of each drive coil CI, C2, C3, and C4, as shown in FIG. 2 (5). As shown, the common terminal 2 of each drive coil and each phase control transistor TRI.

A diode serving as a flybank voltage erasing means is connected only between the common connection point 3 of TR2, TR3, and TR4.

And the current Φ1゜Φ2 flowing through each drive coil. Φ3. Φ
4 is a phase control transistor TRI.

A current/voltage control transistor TRO is used to prevent the generation of a large flyback voltage that would damage the transistor when it is cut off by TR2, TR3, and TR4.
is provided between the power supply and the common connection point 2 of the drive coil. The operation will be explained below. As shown in Figure 2), the step motor drive coils CI, C2, C3,
Phase control 1 of the current flowing through any three of C4
The current/voltage control transistor TR is switched off just a little before the current/voltage control transistor (2 of TRI, TR2, TR3, TR4) is cut off (Fig. 2 (B), Φ0).
The current Φ0 flowing through each drive coil is cut off by O.

Then, the flyback voltage generated across the conductive drive coil 1 of the phase side diagonal transistor is erased by the current flowing through the drive coil, the conductive phase ilJig transistor, and the flyback diode D. I can do it. After the flyback voltage is erased or fd, the flyback voltage is applied to the phase control transistor TR in order to increase the speed of the step motor.
1, TR2, TR3゜Turn off the phase control transistor after it becomes lower than the withstand voltage of TR4 (non-conducting state)
do it. Further, when a phase control transistor that has been made non-conductive is made conductive, there is no particular need to have such a relationship.

Next, a case where the step motor is stopped will be explained. FIG. 2(C) shows the relationship between the supply voltage and the supply current in the step motor drive control method according to the present invention when the step motor is stopped. In FIG. 2 (5), the control unit 1 selects the current voltage at the time of stop.
The mother signal is output from ■0 and input to the power supply voltage control transistor TRO through a resistor, and the power supply voltage is set to 0N.
10FF control to obtain voltage waveform q' and current waveform 4. Therefore, since the power supplied to the step motor is expressed as the product of voltage and current, by chopper controlling the above transistor TKO, the average power supplied to the step motor is reduced, and the drive coil and phase control Transistor overheating is prevented and power consumption is reduced. When the above-mentioned power supply voltage control transistor TRO is subjected to chopper control, the drive coils (C1, C2, C3
. No flyback voltage is applied to the voltage control transistor TRO. Since the control section 1 is generally controlled by a microcomputer, it is easy to establish a certain relationship between the control signals.

■ Effects of the Invention As explained above, according to the present invention, the number of circuit components is reduced compared to the conventional step motor control method, and transistors with low withstand voltage, that is, small-sized transistors can be used. Therefore, miniaturization of the step motor control circuit is achieved. In particular, when the step motor is stopped, the power supplied to the step motor is limited by chopper control of only one transistor, preventing overheating of the transistor for cell smoke and phase control, and saving power consumption. In addition to this, the effect of being able to prevent torque fluctuations due to variations in transistor characteristics is outstanding.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a conventional step motor drive control system and an explanatory diagram of its operation, and FIG. 2 shows an embodiment of a step motor drive control system according to the present invention and an explanatory diagram of its operation. 1 is the step motor control unit, 2 is the common connection point of the drive coil of the step motor, V' is the present invention ((supply pressure waveform when the step motor is stopped), 4 is the same type, and the flow waveform. Patent amount 1. Yojin Fujitsu Ltd. Representative Patent Attorney Mori 1) Hiroshi (1 other person) Figure 1

Claims (2)

[Claims] (1) In a step motor drive system having a switching means for passing a current of a predetermined phase through a plurality of drive coils, and a flyback voltage erasing means, a power supply voltage for controlling the voltage supplied from the power supply to the step motor in a 0N10FF manner. a control means, a common voltage terminal for applying a voltage from the power supply voltage control means to the plurality of drive coils, a switching means for flowing a current of a constant phase to the other ends of the plurality of drive coils, respectively; Driving a step motor, characterized in that a flybank includes pressure erasing means for erasing flyback voltage generated in the drive coil between a common connection point of the switching means and a common voltage terminal of the plurality of drive coils. control method. (2) The step motor drive control method according to item 1, wherein the p power supply voltage is controlled by the power supply voltage control means when the step motor is stopped.