JPH0733599Y2 - Stepping motor drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a driving device for driving a stepping motor with a constant current.

b. Conventional Technology Conventionally, as a stepping motor drive device of this type,
For example, there is one as shown in the block diagram of FIG.

In this drawing, this drive device performs pulse width modulation on a DC output from a DC power source E by a chopper circuit unit 1 including a switching element, and then passes a drive circuit unit 3 through a smoothing circuit unit 2 including a coil L and a capacitor C. Drives the load stepping motor M.

The magnitude of the drive current flowing through the motor M depends on the current detection resistor.
The detected signal value detected by R ₁ is the current command unit 4
The current control unit 5 controls the output pulse width of the chopper circuit unit 1 so as to match the reference value set in. That is, the detection signal value is compared with the reference value, and the switching element is turned on and off with a pulse width corresponding to the detection signal value.
Then, the average output current of the motor M is kept constant.

Further, from the output side of the smoothing circuit section 2, a phase compensation circuit section 6 composed of resistors R ₂ and R ₃ and a capacitor C ₁ takes out a signal of only the AC component of the output voltage, and adds it. 7, the signal is added to the detection signal from the current detection resistor R ₁ and is fed back to the current control unit 5. This is to drive the stepping motor M with a stable constant current by this device, so that the phase delay of the control system by the smoothing circuit unit 2 and the motor M is compensated for and the oscillation of the control system is suppressed.

c. Problems to be Solved by the Invention However, in such a conventional stepping motor drive device, a phase compensation circuit unit for adding a phase lead action is added to suppress oscillation of the control system. . Therefore, the control gain for the drive current to the motor M is reduced, and the constant current control does not sufficiently act in the entire speed range of the motor M. Therefore, the effect of suppressing the medium speed vibration by the constant current control cannot be sufficiently exerted. There was a problem.

That is, FIG. 6 shows the relationship between the output voltage V of the smoothing circuit unit 2 and the divided voltage Vd at the voltage dividing point A ₁ of the phase compensation circuit unit 6 with respect to the speed of the motor M. In the low speed region of the motor M, the oscillation of the control system is suppressed by the phase lead action, but in the medium speed and high speed regions, the divided voltage Vd also increases and the phase compensation action remains effective, so that the control gain decreases. It is impossible to suppress the medium speed vibration.

The present invention has been made in view of such a point, and an object thereof is to solve the above-mentioned problems, and the phase compensating action of the phase compensating circuit section is remarkable in the low speed region of the motor, and the action thereof is remarkable in the middle and high speed regions. It is an object of the present invention to provide a stepping motor drive device that smoothly lowers, enables constant current drive at all times, and simultaneously suppresses oscillation of a control system at low speed and suppresses vibration at medium and high speeds.

d. Means for Solving the Problems The configuration of the present invention for achieving the above-mentioned object is a chopper circuit section including a switching element that interrupts direct current, a smoothing circuit section that smoothes the output of the chopper circuit section, and A drive circuit unit that inputs the output of the smoothing circuit unit to drive the stepping motor, a detection circuit unit that detects the drive current of the motor, and the chopper so that the signal value of the detection circuit unit matches the reference value. A current control unit for controlling the output pulse width of the circuit unit, a phase compensation circuit unit connected to the output side of the smoothing circuit unit, and an addition for adding the signal from the phase compensation circuit unit to the signal of the detection circuit unit. In the driving device including a circuit unit, the phase compensation circuit unit includes a voltage divider circuit and a filter circuit, and the voltage divider circuit inputs the output voltage of the smoothing circuit unit and divides the input voltage. Output Therefore, the voltage output at the voltage dividing output point is composed of a combination of a semiconductor element and a resistor so that the voltage output is saturated in response to an increase in the input, and the filter circuit inputs the output of the voltage dividing circuit and outputs an AC component. It is characterized in that it is taken out and used as the output of the phase compensation circuit section.

e. Operation As described above, the voltage dividing circuit of the phase compensation circuit unit is composed of a constant voltage diode or a combination circuit of a diode, a transistor and a resistor, which increases the motor speed. As the output voltage of the smoothing circuit, which is the basis of the motor drive voltage, increases, the voltage division ratio continuously decreases.

Therefore, the compensating action of the phase compensation circuit section is remarkable in the low speed region of the motor, and smoothly decreases in the middle and high speed regions.

f. Embodiment Hereinafter, a preferred embodiment of the present invention will be exemplarily described in detail with reference to the drawings.

FIG. 1 is a block diagram of a stepping motor driving device showing an embodiment of the present invention. In the figure, reference numeral 11 denotes a phase compensation circuit section, the same elements as those in FIG.

The phase compensation circuit unit 11 includes a resistor R ₁₁ , a constant voltage diode ZD ₁₁ , and a resistor from the output side of the smoothing circuit unit 2.
It is composed of a voltage dividing circuit in which circuits of R ₁₂ and R ₁₃ and a transistor Q ₁₁ are connected in series, and a capacitor C ₁₁ connected between the voltage dividing point A ₁₁ and the adding circuit unit 7.

The constant voltage diode ZD _{11 of the} voltage dividing circuit and the resistors R ₁₂ , R
₁₃ , the combined resistance value of the series circuit with the circuit of the transistor Q ₁₁ acts so as to decrease in accordance with the increase of the applied voltage, that is, the output voltage V of the smoothing circuit unit 2, and the divided voltage Vd at the voltage dividing point A ₁₁ Changes with the motor speed as shown in FIG.

That is, when the stepping motor M is stopped or in the low speed region, the output voltage V from the smoothing circuit unit 2 is lower than the Zener voltage of the constant voltage diode ZD ₁₁ , and the divided voltage Vd
Is approximately equal to the output voltage V. However, when the motor M is in the medium speed range, the output voltage V from the smoothing circuit unit 2 rises and the constant voltage diode ZD ₁₁ is turned on.
Vd is a voltage obtained by dividing the output voltage V by the resistor R ₁₁ and the resistors R ₁₂ , R ₁₃ . Next, when the motor M reaches the high speed region, the output voltage V further increases and the transistor Q ₁₁ is turned on, so that the combined resistance value of the series circuit further decreases and the voltage dividing ratio of the voltage dividing circuit further decreases. To do. The change in the voltage division ratio continuously changes before and after the constant voltage diode ZD ₁₁ and the transistor Q ₁₁ are turned on.

The divided voltage Vd thus obtained is
Since it is sent to the addition circuit unit 7 via ₁₁ , the phase compensating action is remarkable in the low speed region of the motor M, and the action continuously decreases with the speed in the medium speed to high speed region.

FIG. 3 is a block diagram of a stepping motor driving device showing another embodiment of the present invention. In the figure, reference numeral 21 denotes a phase compensation circuit section, the same elements as those in FIG.

The phase compensation circuit unit 21 includes a resistor R ₂₁ , resistors R ₂₂ , R ₂₃ , R ₂₄ , and diodes D ₂₁ , D from the output side of the smoothing circuit unit 2.
The circuit network of ₂₂ and the transistor Q ₂₁ is composed of a voltage divider circuit connected in series, and a capacitor C ₂₁ connected between the voltage dividing point A ₂₁ and the adding circuit 7.

The resistance of the voltage dividing circuit, the combined resistance value of the circuit network of the diode and the transistor is the applied voltage, that is, the smoothing circuit unit 2.
The output voltage V of the
The divided voltage Vd at the voltage dividing point A ₂₁ is 4th with respect to the motor speed.
It changes as shown in the figure.

That is, when the step motor M is stopped or in the low speed region, the output voltage V from the smoothing circuit unit 2 is low, and the divided voltage Vd changes the output voltage V to the resistor R ₂₁ and the resistors R ₂₂ , R ₂₃ . The voltage is divided by. When the motor M is in the medium to high speed range, the output voltage V increases with speed, and the diode D ₂₁ , the diode D ₂₂ , and the transistor Q _{21 of the} circuit network are sequentially turned on. _The divided voltage Vd at ₂₁ gradually decreases continuously and becomes almost AC-like at the maximum speed. Since the circuit network operates just as a variable resistance element whose combined resistance value decreases as the voltage increases, the voltage dividing ratio of the voltage dividing circuit decreases with the motor speed. Then, the phase compensating action decreases with speed as in the previous embodiment.

The technique of the present invention is not limited to the technique in the above-described embodiment, and means of another aspect having the same function may be used, and the technique of the present invention may be modified in various ways within the scope of the configuration. Can be added.

g. Effect of the Invention As is apparent from the above description, according to the stepping motor drive device of the present invention, the voltage dividing circuit in the phase compensation circuit unit increases the motor speed, that is, the output voltage of the smoothing circuit unit. Since the output voltage from the divided voltage output point is saturated according to the rise, the circuit is composed of a combination of a semiconductor element and a resistor. Is remarkable in the stop and low speed regions, and its action continuously decreases in the middle and high speed regions.

Therefore, the present drive device has a sufficient control gain even in the middle and high speed regions of the motor, and constant current drive is possible in the entire speed range of the motor.

[Brief description of drawings]

FIG. 1 is a block diagram of a stepping motor driving device showing an embodiment of the present invention, FIG. 2 is a characteristic diagram of DC voltages V and Vd with respect to motor speed in FIG. 1, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a block diagram of a stepping motor drive device showing an example, FIG. 4 is a characteristic diagram of DC voltages V and Vd with respect to motor speed in FIG. 3, FIG. 5 is a block diagram of a conventional stepping motor drive device, and FIG. 5 is a characteristic diagram of DC voltages V and Vd with respect to the motor speed in FIG. 5. FIG. 11, 21 ... phase compensating circuit unit, C _11, C ₂₁ ... capacitor, D _21, D
₂₂ … Diode, Q ₁₁ , Q ₂₁ … Transistor, R ₁₁ , R ₁₂ ,
_{R 13, R 21, R 22} , R 23 ... resistors, ZD ₁₁ ... constant voltage diode.

Claims (1)

[Scope of utility model registration request] 1. A chopper circuit section including a switching element for connecting and disconnecting a direct current, a smoothing circuit section for smoothing an output of the chopper circuit section, and a drive circuit section for inputting an output of the smoothing circuit section to drive a stepping motor. A detection circuit section for detecting the drive current of the motor; a current control section for controlling the output pulse width of the chopper circuit section so that the signal value of the detection circuit section matches a reference value; and the smoothing circuit. In a drive device comprising a phase compensation circuit unit connected to the output side of the unit and an addition circuit unit that adds the signal from the phase compensation circuit unit to the signal of the detection circuit unit, the phase compensation circuit unit is a voltage divider. The voltage dividing circuit is composed of a circuit and a filter circuit, and the voltage dividing circuit inputs the output voltage of the smoothing circuit unit, divides the input voltage, and outputs the voltage. The voltage output at the voltage dividing output point rises in the input. Tired of The stepping is characterized by comprising a combination of a semiconductor element and a resistor so that the filter circuit receives the output of the voltage dividing circuit, extracts an AC component, and outputs the AC component as an output of the phase compensation circuit section. Motor drive device.