JPH0487598A - Drive controller for stepping motor - Google Patents

Abstract

PURPOSE:To suppress wasteful power consumption and heat generation and to obtain a torque in a high speed rotation zone with a simple circuit configuration by providing a supply voltage controller for varying a supply voltage to a stepping motor in response to the output of a clock generator. CONSTITUTION:It is now assumed that a low speed rotation drive command is input to a clock generator 1. The generator 1 reduces the number of pulses per unit time and outputs it. An excitation controller 2 forms an exciting pattern of a coil corresponding thereto, and outputs it to a power amplifier 3. On the other hand, an F/V converter 4 outputs a voltage responsive to the number of pulses. Accordingly, a current waveform smoothly rises, completely rises, and a sufficient torque is obtained. When a high speed rotation drive command is then input to the generator 1, the number of pulses is increased and output, an exciting pattern corresponding thereto is formed and output. The converter 4 outputs a high voltage, and supplies a drive power. Accordingly, an exciting time is short, but an abrupt rise occurs, and sufficient torque is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive control device for a stepping motor.

(Prior Art) Conventionally, stepping motors have been widely used because they can be digitally controlled and the rotational speed can be arbitrarily controlled at a pulse rate. However, there was a drawback that the torque of the motor decreased as the rotation speed increased.

Therefore, in order to quickly start up the current flowing through the coil even at high speeds, we have developed a series resistance circuit that reduces the time constant by connecting a resistor in series with the winding, and a series resistance circuit that applies a high voltage at the rise of the current waveform. Constant voltage drive circuits such as voltage drive circuits, constant current driver circuits, etc. are being considered.

(Problem to be solved by the invention) However, series resistance circuits have disadvantages such as wasteful power consumption due to series resistance and temperature rise due to heat generation, and dual voltage drive circuits have disadvantages of requiring power supplies with different voltages. there were.

On the other hand, constant current chopper drive circuits can obtain more torque in high speed rotation ranges than constant voltage drive circuits, but have the disadvantage that they are difficult to use in low speed rotation ranges and have a complicated circuit configuration.

The present invention has been made in view of the above-mentioned conventional drawbacks, and includes:
The object of the present invention is to provide a stepping motor drive control device that can suppress wasteful power consumption and heat generation, and can also obtain torque in a high-speed rotation range with a simple circuit configuration.

(Embodiment) In the figure, ``■'' is a clock generation circuit that receives a drive command requesting driving of the stepping motor 7 from another am circuit and generates a 14aI pulse for changing the excitation speed of the motor. Reference numeral 2 denotes an excitation control circuit that receives clock pulses from the clock generation circuit 1 and creates an excitation pattern for the motor coil. Reference numeral 3 denotes a power amplification circuit that amplifies the power of the excitation pattern of the excitation control circuit 2 and drives the stepping motor 7 with power from a supply voltage control circuit 5, which will be described later. 4 is F which converts the output of clock generation circuit l into voltage.
-V conversion rgIglI, which outputs a voltage corresponding to the number of pulses to the supply voltage control circuit 5. Supply voltage l11
The 81 circuit 5 supplies the power supplied from the power supply circuit 6 to the power amplifier circuit 3 as driving power for the stepping motor, and converts the supplied voltage into the F-V conversion circuit 4.
It is variable depending on the output.

Next, the operation of the above configuration will be explained.

Assume now that a low-speed rotation drive command is input to the clock generation circuit l. The clock generation circuit 1 outputs a reduced number of pulses per unit time. The excitation control circuit 2 creates a coil excitation pattern in response to this and outputs it to the power amplification circuit 3. On the other hand, the F-V conversion circuit 4 outputs a voltage according to the number of pulses. Now the power supply circuit 6 is DC 30
If V is supplied, the supply voltage control circuit 5
Depending on the output of the -V conversion circuit 4, the voltage is stepped down to, for example, IOV and supplied to the power amplifier circuit 3 as a driving power source. Therefore,
At this time, the current waveform in the coil has a gradual rise as shown in FIG. 2, but it rises completely, and sufficient torque can be obtained.

Next, when a high-speed rotation drive command is input to the clock generation circuit 1, the clock generation time ml is outputted with an increased number of pulses. The excitation control circuit 2 creates and outputs an excitation pattern corresponding to this as in the previous case.

The F-V conversion circuit 4 outputs a higher voltage than the previous time, and the supply voltage wait circuit 5 outputs a voltage higher than the previous one, for example.
A driving power source with a voltage of 0V is supplied to the power amplifier circuit 3. Therefore, as shown in FIG. 3, the current waveform of the coil at this time has a short excitation time but has a sharp rise. Therefore,
You can also get enough torque.

The above explanation was given in the low speed range and high speed range, but the same applies to the medium speed range.If you try to increase the motor speed, the supply voltage to the motor will be high.If the rotation speed decreases, the supply voltage will also increase. It will go down.

In other words, the relationship between the supply voltage and the rotational speed of the motor is as shown in FIG. The current flowing through the coil rises completely to the rated current even at high speeds, and the torque remains constant regardless of the rotational speed as shown in FIG.

Therefore, if you experimentally find out how many V of supply voltage should be applied at what Hz clock in the operating rotation range, and have the supply voltage control circuit 5 maintain that relationship,
This allows stable torque to be obtained at all times.

(Effects of the Invention) As described above, according to the present invention, it is possible to make the torque characteristics of a stepping motor linear with respect to the rotational speed, thereby eliminating wasteful power consumption unlike conventional constant voltage drive circuits. Sufficient torque can be obtained without generating heat or heat.

Moreover, the circuit structure does not have to be complicated as in the conventional constant-voltage transistor drive circuit, and moreover, it can be used even in the low-speed rotation range.

[Brief explanation of drawings]

FIG. 1 shows a circuit block diagram of an embodiment of the present invention, and FIGS. 2 and 3 are explanatory diagrams of voltage and current waveforms of a motor coil. FIG. 4 is a characteristic diagram of supply voltage and rotational speed, and FIG. 5 is a characteristic diagram of torque and rotational speed. l... Clock generation circuit 2... Excitation control circuit, power amplifier circuit, F-V conversion circuit, supply voltage am circuit, power supply circuit, stepping motor

Claims (1)

[Claims] A device for driving a stepping motor that includes a clock generation circuit that outputs control pulses for the stepping motor, an excitation pattern generation circuit, and a power amplification circuit,
A stepping motor drive control device comprising a supply voltage control circuit that varies the voltage supplied to the stepping motor in accordance with the output of the clock generation circuit.