A Wire Feed Control System Based on Detecting Induced Electromotive Force of the Motor

A stable and even wire feed speed is a guarantee of good quality welding. A new wire feed system, without any speed-measuring equipment, has been designed. And the motor current of this system works in a discontinuous state. When the motor current is zero, it detects the induced electromotive force; acquires the motor speed according to the relationship between the induced electromotive force and the motor speed; calculates and compares with the given speed then changes the duty cycle of the voltage added on the motor by PWM technology, that control the motor speed. Then a stable and even wire feed speed can be achieved. Verified by testing resistance, the change rate of the wire feed speed is slightly, which proves that the new system has good mechanical properties and a stable speed. Besides, it runs reliably.