| 摘要 |
A one-cycle Power Factor Correction method, based on a boost circuit and a system main control chip, the boost circuit comprising an AC input terminal, a rectifier circuit, an inductor, a fast recovery diode, a capacitor, a DC output terminal, an inductor current sampling circuit, an output voltage sampling circuit, a switch tube drive circuit, and a switch tube is disclosed. The control method includes following steps: (1) judging whether a soft start is finished, if finished, directly going into step (2); otherwise, increasing an output voltage reference value Uref, and going into step (2); (2) reading out a bus voltage sampling value Uo and an inductor current sampling value ig according to an AID sampling triggering time; (3) calculating a duty cycle of a PWM signal driving the switch tube by Calculating parameters U1 and U2 according to the formula depicted in the drawing wherein Rs is an equivalent current sense resistance, Um is a value of a difference between an output bus voltage reference value Uref and the bus voltage sampling value Uo from the output of a PI regulator; obtaining the duty cycle of the PWM signal based on at least the parameter u1; (4) outputting the PWM signal according to the duty cycle of the PWM signal and a comparison of the parameters u1 and u2; (5) calculating a next A/D sampling triggering time according to the duty cycle of the PWM signal; and (6) returning to step (2). |
