CS234176B1 - Connection of stepper motor stage - Google Patents

Abstract

Connection of the final stage of a stepper motor powered by a sinusoidal excitation voltage, consisting of a final amplifier, feedback elements and an electronic switch. The sinusoidal excitation voltage is connected to the input of the final amplifier. Its output is connected to the inputs of the feedback elements and to the load impedance of the stepper motor winding. The outputs of the feedback elements are connected in parallel and connected to the inverting input of the final amplifier. The control signals of the electronic switch are fed to the second inputs of the feedback elements, the input of which is the control word for selecting the type of feedback element.

Description

The invention relates to an output stage of a stepper motor powered by a sine excitation voltage, consisting of an output amplifier, feedback elements and an electronic switch.

The current design of the output stages supplying the individual phases of the winding of the stepper motor basically takes into account two possible ways of controlling the stepper motor. Firstly, a more frequent method of discrete control, with individual winding phases being switched by switching elements degrees amplify the input signal of a sine wave whose frequency is proportional to the speed of the stepper motor. In both cases, with increasing motor speed, the output impedance of the output stages increases because the individual stator windings of the stepper motor have an inductive character. In order not to decrease the output current supplied by the output stages to the motor at higher speeds and thus to the torque on the shaft, there are methods of solving the output stages such as constant current sources to the motor windings or switchable voltage sources. However, there are applications of stepper motors, where the motor operates, for example, in variable-duty operating modes or cycles, the dependence of which is known in the operation, and where it is appropriate for the power stages to supply the stepper motor with sufficient current for economical reasons. The regulation of the current to the motor is required to be continuous, depending, for example, on the motor speed and the magnitude of the known load. Existing method of solution

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In power stages it was not possible to regulate the current according to the speed of rotation and the known load torque.

The aforementioned drawback in the case of controlling stepper motors with sine wave excitation signals removes the need to do so. of the stepper motor according to the invention. Its essence is that the output of the sinusoidal excitation voltage is connected to the input of the final amplifier, the output of which is connected both to the inputs of the feedback members and to the load impedance of the winding of the stepper motor. The outputs of the feedback members are connected in parallel and connected to the inverting input of the amplifier. The outputs of the electronic switch are connected to the second inputs of the feedback members.

A specific example of wiring is given in the attached drawing.

The sinusoidal excitation voltage is connected to the non-inverting input of the final amplifier 1. Its output is connected both to the inputs of the feedback members 4, 4 and to the load impedance X _{from the} winding of the stepper motor. The outputs of the feedback members 4, 4 ... n are connected in parallel and connected to the inverting input of the output amplifier 1. The control inputs of the electronic switch 2, the input of which is the control word for selection, are applied to the other inputs of the feedback members. feedback type.

The power amplifier 1 are connected to the feedback member 4 ··· X on the load impedance _{of the} windings of the stepper motor. The feedback members 4, 4 ·, n introduce negative feedback in the amplifier 1 depending on the speed of rotation of the motor and on the operating mode of the stepper motor. The feedback elements 4, 4 ··· S are designed such that for a given operating mode of the stepper motor the magnitude of the output voltage of the amplifier 1 and the current to the winding of the load impedance X _{z is} given by the known course of the stepping motor load torque. and thus i

- 3 234 17β torque reserve of powered stepper motor.

In each operating mode, only one and feedback member J1, ..., a is energized, the switching being effected via an electronic switch 2, the input of which is the operating mode type control word.

During the individual operating modes of the stepper motor, which can be considerably long in time, by suitable selection of the feedback member for the given mode, the stepper motor is economically powered according to a predetermined load torque curve and thus energy savings of the entire drive.

Claims (1)

Connection of the output stage of a stepper motor powered by a sine excitation voltage, consisting of an amplifier, feedback members and an electronic switch, characterized in that the output of the sine wave excitation voltage is connected to the input of the amplifier (1) whose output. it is connected both to the inputs of the feedback elements (3, 4 .. n) and to the load impedance (X ^) of the stepping motor winding, the outputs of the feedback elements (3, 4 ·· n) are connected in parallel and connected to the inverting input of the the outputs of the electronic switch (2) are connected to the second inputs of the feedback members (3, 4 .. n).