BOOST PFC convertor starting output voltage anti-overshoot digital control method

The present invention discloses a BOOST PFC convertor starting output voltage anti-overshoot digital control method. Control signals and reference voltage signals of PWM are changed through a DSP controller and a program, and the control of the algorithm is realized in the response interruption mode. At the moment of starting a PFC circuit, main power switch tube PWM signals are turned off so that the switch tube is located at the turn-off phase; and when the output direct voltage is equal to or close to a rectified output voltage, the reference value of the output voltage is equal to the rectified voltage, and the PWM signals are turned on. The reference voltage is changed to gradually increase to a setting value of the output voltage so that a soft-start function is completed. Without adding any hardware circuit elements, the starting output voltage overshoot of a BOOST PFC convertor may be avoided in a simple and effective digital control mode.