Composition of stepping motor drive

2022-01-14 11:17:42 admin 2

Unipolar stepping motor and bipolar stepping motor are the two most commonly used driving structures of stepping motor.

The driving circuit of unipolar stepping motor uses four transistors to drive two groups of phases. The structure of the stepping motor is shown in Figure 1, including two groups of coils with intermediate taps. The whole motor has six wires connected to the outside.

This kind of stepping motor is sometimes called four phase stepping motor, but it is easy to be confused and misjudged because it has only two phases and the accurate expression is two-phase six wire stepping motor.

Six wire stepper motor is also called unipolar stepper motor, but it can use unipolar and bipolar driving circuits at the same time.

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Unipolar stepping motor driving circuit

The driving circuit of bipolar stepping motor is shown in the figure. It uses eight transistors to drive two groups of phases.

Bipolar drive circuit can drive four wire or six wire stepping motor at the same time. Although four wire motor can only use bipolar drive circuit, it can greatly reduce the cost of mass production application.

The number of transistors in the bipolar stepper motor drive circuit is twice that of the unipolar drive circuit. Four lower end transistors are usually driven directly by the microcontroller, while the upper end transistors need a higher cost upper end drive circuit.

The transistor of bipolar drive circuit only needs to bear motor voltage, so it does not need clamping circuit like unipolar drive circuit.