Abstract: A mathematical model of three-phases voltage PWM converter was established, two implementation methods of grid voltage orientation control of PWM converter were analyzed in details. According to vector relation of grid voltage and line voltage, an implementation method of grid voltage orientation of grid side PWM converter of doubly-fed power excitation system was determined. An experimental platform of three-phase voltage PWM converter was built by taking TMS320F2812 as main control chip, and zero-crossing comparator and software were designed. The experimental result indicated that the control method is correct and valid.