JPS623679B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a step motor driving method that increases the maximum instantaneous reversible frequency of the step motor, particularly during reversal.

Conventionally, when reversing the step motor, for example, as shown in FIG.
The phase and fourth phase are immediately switched to the second and third phases, but in this case, inertia force in the rotational direction due to the third and fourth phase excitation is acting on the rotor. , the maximum instantaneous reversible frequency during this reversal is generally greatly reduced to about 1/2 of the frequency before reversal, which makes it difficult to use, for example, for air-fuel ratio control in automobiles that frequently repeat forward and reverse rotations. In the step motor, the responsiveness of the step motor is lowered, making it difficult to follow the air-fuel ratio control, and the drive circuit of the step motor becomes complicated.

An object of the present invention is to provide a method for driving a step motor that utilizes the inertia force in the reversal direction generated by the vibration damping characteristics unique to the step motor when the step motor is reversed by a reversal signal.
The object is to eliminate the above-mentioned conventional drawbacks.

Next, the configuration of an embodiment of the present invention is shown in FIGS. 2 to 5.
This will be explained using figures.

Figure 2 shows the step motor drive circuit.
The circuit connects the voltage corresponding to the inverted signal input to the non-inverting input terminal of the operational amplifier OP1 through the CR filter 1 of the resistor R1 and the capacitor C1 to the inverting input terminal of the operational amplifier OP1. Resistance R
2, R3, a forward/reverse rotation determination circuit 3 that compares the reference voltage with the reference voltage of the reference voltage setting circuit 2, and resistors R4, R5, and capacitor C each time a forward/reverse inversion signal is input.
2, C3, inverter INT1, NAND gate
By the trigger pulse generated from the trigger pulse generation circuit 4 of NAND1, the resistor R6 and the capacitor C
4. Inverter INT2, INT3, Noah gate NOR
For a certain period of time determined by the pulse width of the monostable multivibrator 5 of 1, in this case, due to the vibration damping characteristics peculiar to the step motor shown in FIG. For example, if the rotor has an outer diameter of 10 to 25
A phase excitation fixed time forming circuit 6 that generates an output for 4 to 8 msec at mm, and "L" from the circuit 6
A clock pulse generator 7 consisting of resistors R7 and R8, a capacitor C5, and NAND gates NAND2 and NAND3 which stop the generation of clock pulses for a certain period of time by the output, and the output from the forward/reverse rotation determination circuit 3 are input to the up/down terminals, and and a distribution excitation circuit 8 for inputting pulses from a clock pulse generator 7 to a clock terminal.

Next, the operation of this embodiment will be explained.

First, when looking at the 1-step displacement (1-step response) for a 1-pulse input signal of the step motor, the relationship between the displacement angle of the rotor and the elapsed time for 1-step response is as follows: The step motor is PM type, the rotor outer diameter is 10 mm, If a motor with 24 phase poles is used and the excitation method is two-phase excitation, the motion of the rotor will be as shown in Figure 4, and the rotor will reach a stable position between O and t1 in Figure 4.
15 degrees, it rotates in the direction of rotation of the 1-pulse input signal (clockwise), and between t1 and t2, it initially tries to return to the stable position and rotates counterclockwise, passing the stable position and continuing this movement. Iteratively decays.

Therefore, when the rotor is instantaneously reversed by a reversal signal, in order to input the reversal signal between O and t1 in FIG. It must be rotated counterclockwise, from t1 to t2 in Figure 4.
When the rotor is reversed in between, the inertia force is acting in the same direction as the reversal direction, so it can be seen that the rotor can be reversed easily and quickly with the help of the counterclockwise inertia force.

Therefore, when the rotor is momentarily reversed by the reversal signal, the phase excitation immediately before the reversal signal is fixed for a certain period of time required for the inertia force in the reversal direction to be generated in the rotor.

That is, in FIG. 2, even if the inverted signal from the forward/reverse rotation determination circuit 3 is input to the up/down terminals of the distribution excitation circuit 8, the "L" level from the monostable multivibrator 5 when this inverted signal is input is Depending on the output, the clock pulse output from the clock pulse generator 7 is fixed for a certain period of time required for the inertia force in the reverse direction to occur in the rotor, and for example, as shown in FIG. When an inversion signal is input in this state, this phase excitation state becomes
After the rotor is fixed for a certain period of time required to generate inertia in the reverse direction, a clock pulse is generated and the second clock pulse is generated.
phase and third phase are energized.

The maximum instantaneous reversal frequency with this drive method is as shown in Figure 5, according to actual measurement results of two-phase excitation of a PM type step motor with a rotor outer diameter of 10 mm, 4 phases, and 24 steps. The reversible frequency can be increased from 100 to 100 by providing a fixed excitation stop time.
200PPS (Hz), especially in the case of a step motor with the above specifications, by providing a fixed excitation stop time of 4 to 8 msec, the capability of the step motor can be maximized. It has been confirmed that for 14 mm, 20 mm, 25 mm, 4-phase, 24 step step motors, by providing a fixed excitation stop time of 4 to 8 msec, the maximum instantaneous reversible frequency can be improved almost in the same manner as described above.

Next, the effects of the present invention will be explained.

The present invention provides a method for reversing the step motor when driving the step motor in the forward or reverse direction using phase excitation outputs for driving the step motor from the distributed excitation circuit that are generated in response to the forward or reverse command signal and the clock pulse frequency. In order to smooth the operation and improve the responsiveness of the step motor, when the step motor is driven in reverse by reversing the forward/reverse command signal, the phase excitation immediately before the input of the reversal signal is applied to the rotor of the step motor. is fixed for a predetermined time required to generate inertia force in the reverse direction due to
The method of driving a step motor includes generating a phase excitation output for driving the step motor in accordance with the reversal signal from the distributed excitation circuit to drive the step motor in reverse when an inertial force in the reversal direction acts on the rotor after the predetermined time has elapsed.

As a result, the present invention can greatly increase the maximum instantaneous reversible frequency of the step motor, and the cumulative response time after reversal becomes faster.
For example, when this driving method is used, the control characteristics of air-fuel ratio control for automobiles can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is an operation diagram showing the phase excitation sequence of a conventional embodiment, Fig. 2 is a circuit diagram of an embodiment of the present invention, Fig. 3 is an operation diagram showing the phase excitation sequence, and Fig. 4 and Figure 5 is a diagram of its operating characteristics,
τo in FIG. 4 indicates the delay time. 3... Forward rotation/reverse rotation determination circuit, 4... Trigger pulse generation circuit, 5... Monostable multivibrator, 6... Phase excitation fixed time forming circuit, 7... Clock pulse generator, 8... Distribution excitation circuit.

Claims (1)

[Claims] 1 When driving the step motor in forward or reverse rotation using the phase excitation output for driving the step motor from the distributed excitation circuit, which is generated in response to the forward or reverse rotation command signal and the clock pulse frequency, the reversal operation of the step motor is controlled. In order to improve the response of the step motor, when the step motor is driven in reverse by reversing the forward/reverse command signal, the phase excitation immediately before the input of the reversal signal is applied to the rotor of the step motor to reverse the reversal caused by the reaction. A fixed time period required for generation of directional inertia force is fixed, and when inertia force in a reversal direction acts on the rotor after the elapse of the predetermined period of time, a phase excitation output for driving the step motor is generated from the distributed excitation circuit by the reversal signal. A step motor driving method characterized by driving the motor in reverse.