Internal combustion direct current arc welding machine current regulator

The current regulator for internal combustion DC arc welder includes one rectifier circuit connected to the generator exciting winding, one micro controller and one starting circuit. The micro controller generates the PWM control signal to control the exciting voltage and has I/O interface connected to the digital display and the operation keyboard; and the starting circuit establishes exciting voltage essential for the generator to operate stably. One error detecting circuit is connected between the exciting winding and the micro controller to compare the sampled exciting voltage signal and the reference current signal the micro controller inputs, and the micro controller processes the operation result for regulating the duty ratio of the output PWM control signal. The present invention has simple structure and capacity of ensuring the stability of the arc welder.