JPS61203899A - Operating method for step motor - Google Patents

Abstract

PURPOSE:To normally perform a function as an actuator without losing a controllability by using the remaining wirings when a winding is disconnected to switch to a unifilar bipolar drive for applying a voltage. CONSTITUTION:When wirings to be applied with a step voltage are disconnected, a corresponding voltage application signal is not input to a detector S irrespective of the output of step voltage to windings A1, A2. Accordingly, a disconnection is decided. At this time, it is switched to apply the step voltage by not disconnected wirings. The judgement and switching of the disconnection are performed by a control unit C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for operating a step motor, and more particularly, to a method for continuing operation without impairing controllability when a wire is broken in a step motor having a piezoelectric structure. It is something.

As is well known, a step motor rotates a rotor having a permanent magnet or a magnetic material in a stepwise manner in forward and reverse directions by converting an input waveform into a step waveform and applying it to the windings of a stator. It is widely used as an actuator to control the air-fuel ratio of automobile engines.

In view of torque characteristics, most of them have a four-phase structure with a pie-fila winding, and one or two phases are excited to create a bipolar structure! A is doing a lot of things.

Figure 5 shows step motor M, 1! This is one of the circuit diagrams that connects the power supply V and the electronic control unit C. If any of the two wires on the power supply side and the four wires on the control side are disconnected, controllability will be significantly impaired and the step Motor M will no longer function properly as an actuator.

The present invention relates to a step motor having a two-phase, pair of windings and a pie-filar winding structure, in which one power source is connected to any pair of the windings.

The object of the present invention is to provide an operating method in which controllability lfi does not deteriorate even if either of the two control-side wires is disconnected, and the actuator functions normally.

In a sixth aspect of the present invention, in a step motor with a bipolar winding structure, when one of the wires connected to a pair of two-phase windings is disconnected, the disconnection is detected and the bipolar motor with a unifyr winding structure is used with the remaining wire. This is a means to solve the above problems by switching to the drive mode and continuing the operation.

Example Embodiments of the present invention will be explained with reference to the drawings.

In the circuit diagram shown in FIG. 1, a step motor M having a four-phase structure with pie-filar windings includes an electronic control unit C and a power supply circuit V that apply a step voltage to the windings AI and A2, and the control unit C and each winding AI, A2 terminal 1.2.3.4
．． Each of the wires connecting 5 and 6 is connected to the detection circuit S, and whether or not a voltage is applied to each phase of winding A1 and winding 2 is input to the detection circuit S. The voltage application signal is input as a detection signal to the control unit (C) to determine whether or not there is a disconnection. That is, if the line to which the step voltage is to be applied is disconnected, the corresponding voltage application signal is not manually applied to the detection circuit S regardless of whether the step voltage is being output to the windings AI and A2, so the line is disconnected. I know that there is. At this time, the step voltage is applied using the unbroken wire.
Determination of wire breakage and switching are performed by control 22)C.

Normally, the step motor M is operated with a step voltage controlled by turning on and off a transistor. FIG. 2 is its circuit diagram.

Each terminal of two pairs of two-phase windings AI and A2 1. λ3゜4
, 5.6, transistors Trt, Try, Trz, Tr
a, Trs, Trs.

Trt, Trto, Trs, Trt t, Trg,
Two Tr12 are each combined, and the signal line 81. which leads to the detection circuit S. S2, 33. S4,8
5.86 are connected to each other, and each transistor Tr1.
...The control signal voltage of the control unit C is applied to the pace of Tr12.

In such a configuration, in a normal state, the step motor M has transistors Trl, Trg, and Trs.

It is operated by turning Tr4, Tr5, and Trg on and off. Here, 9, for example, the transistor Tr
Even though l is turned on, the fact that voltage is not yet applied to terminal l2 is fed back to control unit C via signal line S1 or S2 via detection circuit S. At this time, it is determined that the line from the transistor Tr1 to the terminal 1 is disconnected, and from then on, the line from the transistor Tr2 to the terminal 1 is disconnected. Tr
3.

Trg Trg is used to apply a step voltage to the winding A1.

When the line from transistor Tr2 to terminal 2 is disconnected, transistors Tr1, Trs, and terminal 7. When Tre is used and the line from transistor Tr3 to terminal 3 is disconnected, transistors Try, Tr2゜'l'r7
Use Tri. Transistors Tr4, Trs, Tra, Trzo, Trl used for the other winding A2
The same applies to t and Trtz.

Here, FIG. 3 is an explanatory diagram of a step motor M having a four-phase structure with a pie-filar winding.One rotor RtlI: each winding ii of a pair of two phases arranged surrounding each other.

One direction of the current flowing through A2 is indicated by an arrow,
Turn on step voltage applied to each phase.

By controlling the number of off times and the direction of application, the rotor R
can be rotated forward and backward to the desired angle.

In the windings AI and A2, as shown in FIG.
(cl (di(e)(fl) Even if current is passed only between two terminals as shown by the arrow
The same rotating magnetic field is generated in each case of (bl (cl) and (dl (el (fl). That is, any one of the three terminals 1.2.3 and 4, 5.6 is disabled. It can be seen that a rotating magnetic field is generated even if the wire is disconnected.Therefore, if any wire is disconnected, normal function can be maintained by switching to bipolar drive in the unifier winding structure by control unit C. .

In FIG. 2, a resistor, which is widely used for improving step motor characteristics and reducing heat generation, can be inserted in parallel with transistors Trl and Tr4.

1. In the present invention, as means for detecting wire breakage, a rotating magnetic field within a step motor, a rotation angle of the step motor,
It is also possible to use indirect detection means based on the operating status of the target device, and when an abnormality in the step motor is detected based on these detection signals, to sequentially selectively control the transistors to find out which wire has broken.

As described above, according to the present invention, when one of the wires connected to the windings of a step motor with a bifilar winding structure is disconnected, the remaining wire is used to apply a step voltage to the unifier winding bipolar drive. Since the actuator is switched, it can function normally as an actuator without compromising controllability.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a control circuit diagram of a step motor, and FIG. 3 is an explanatory diagram of a step motor.
FIG. 4 is a diagram showing the current flow in the winding, and FIG. 5 is a circuit diagram of a conventional example. M...Step motor, AI, A2...
・Winding wire. C...control unit, s...detection circuit.

Claims (1)

[Claims] When one of the wires connected to a pair of two-phase windings is disconnected in a step motor with a wire-wound structure,
A step motor operating method characterized by detecting a wire breakage and switching to bipolar drive in a unifyr winding structure using the remaining wires to continue operation.