Motor driver working principle

The working principle of a motor driver is to receive weak electrical signals (such as pulses or commands) from the control system, process them through internal circuitry, and convert them into strong electrical drive signals. This precisely controls the energizing sequence, current magnitude, and timing of the motor windings, thereby adjusting the motor's speed, direction, and position. The following is a step-by-step analysis of the core principle:

Signal Input: Receives instructions from the controller (such as a PLC or microcontroller), including:

Pulse Signal (PUL): Determines the motor's rotation angle and speed (each pulse corresponds to a fixed step angle).

Direction Signal (DIR): Controls the motor's clockwise or counterclockwise rotation.

Signal Processing: Internal logic circuits (such as a pulse distributor) parse the instructions and calculate the phase sequence of the motor windings to be activated (e.g., phase A → phase B → phase C).

Power Amplification: Converts weak current signals (e.g., 5V) to strong current (24V–48V) through H-bridge or MOSFET circuits to drive the motor windings.

For example, stepper drivers use chopper constant current technology to monitor the winding current in real time and adjust the duty cycle to ensure current stability.

Current Control: A critical component that determines the motor's output force.

Constant Current Drive (Mainstream Technology): Detects current through a sampling resistor and dynamically switches the power transistor to maintain the target current, avoiding overheating and improving high-speed performance.

Subdivision drive: Subdivides a single step angle (e.g., 1.8°) into microsteps (e.g., 1/16 step), reducing vibration and improving accuracy.