A portable welding system, comprising: a display configured to display a graphical user interface; a power input configured to receive mains power; and being further characterized by the following: a rectifier connected to the power input and configured to output a rectified voltage; a first full bridge converter, in communication with the rectifier, that converts the rectified voltage to a first AC voltage; a control board, a pulse wave modulated controller, and a pulse transformer |, wherein the control board supplies first and second pulse wave modulated signals (PWMA, PWMB) generated by the PWM controller to the first full bridge converter and controls switches (SW1, SW2, SW3, SW4) of the first full bridge converter through signals (PWM1, PWM2, PWM3, PWM4) generated by the pulse transformer | that convert the rectified voltage to the first AC voltage, and the control board supplies one third pulse wave modulated signal (PWMC); a main transformer configured to transform the first AC voltage to a second AC voltage; an output rectifier, in communication with a secondary of the main transformer, configured to rectify the second AC voltage and output a DC welding current; and an AC unit, comprising a second full bridge converter comprising switches (SW7, SW8, SW9, SW10) configured to receive an output of the output rectifier, and selectively output at least one of the DC welding current or an AC welding current according to user input received via the graphical user interface, wherein the AC unit receives the third PWM signal (PWMC) from the control board that controls a frequency and a duty cycle of the AC welding current, and wherein the DC welding current, when output, passes through at least one of the electronic switches (SW7, SW8, SW9, SW10) of the second full bridge converter. a display configured to display a graphical user interface; a power input configured to receive mains power; and being further characterized by the following: a rectifier connected to the power input and configured to output a rectified voltage; a first full bridge converter, in communication with the rectifier, that converts the rectified voltage to a first AC voltage; a control board, a pulse wave modulated controller, and a pulse transformer |, wherein the control board supplies first and second pulse wave modulated signals (PWMA, PWMB) generated by the PWM controller to the first full bridge converter and controls switches (SW1, SW2, SW3, SW4) of the first full bridge converter through signals (PWM1, PWM2, PWM3, PWM4) generated by the pulse transformer | that convert the rectified voltage to the first AC voltage, and the control board supplies one third pulse wave modulated signal (PWMC); a main transformer configured to transform the first AC voltage to a second AC voltage; an output rectifier, in communication with a secondary of the main transformer, configured to rectify the second AC voltage and output a DC welding current; and an AC unit, comprising a second full bridge converter comprising switches (SW7, SW8, SW9, SW10) configured to receive an output of the output rectifier, and selectively output at least one of the DC welding current or an AC welding current according to user input received via the graphical user interface, wherein the AC unit receives the third PWM signal (PWMC) from the control board that controls a frequency and a duty cycle of the AC welding current, and wherein the DC welding current, when output, passes through at least one of the electronic switches (SW7, SW8, SW9, SW10) of the second full bridge converter. a rectifier connected to the power input and configured to output a rectified voltage; a first full bridge converter, in communication with the rectifier, that converts the rectified voltage to a first AC voltage; a control board, a pulse wave modulated controller, and a pulse transformer |, wherein the control board supplies first and second pulse wave modulated signals (PWMA, PWMB) generated by the PWM controller to the first full bridge converter and controls switches (SW1, SW2, SW3, SW4) of the first full bridge converter through signals (PWM1, PWM2, PWM3, PWM4) generated by the pulse transformer | that convert the rectified voltage to the first AC voltage, and the control board supplies one third pulse wave modulated signal (PWMC); a main transformer configured to transform the first AC voltage to a second AC voltage; an output rectifier, in communication with a secondary of the main transformer, configured to rectify the second AC voltage and output a DC welding current; and an AC unit, comprising a second full bridge converter comprising switches (SW7, SW8, SW9, SW10) configured to receive an output of the output rectifier, and selectively output at least one of the DC welding current or an AC welding current according to user input received via the graphical user interface, wherein the AC unit receives the third PWM signal (PWMC) from the control board that controls a frequency and a duty cycle of the AC welding current, and wherein the DC welding current, when output, passes through at least one of the electronic switches (SW7, SW8, SW9, SW10) of the second full bridge converter.