Research On Power Factor Correction For Switching Power Supply Based On DSP

The switching power supply is widely used in electric machine and equipment for its excellent characteristic of small, light, high efficiency, low heat and constant capability. In the traditional AC-DC circuits, the rectifier made by diode connected with power network, produce plenty of current distortion and contaminate the network, the power factor is low. To increase the power factor of AC-DC input, the method of power factor correction is used.This paper implement high frequency switching power supply power factor correction by TMS320F2812, analyses the control method and realization of PFC. The equation about the per-unit value of parameter in the software program is deducted. In order to remain the output power at a specified level which determined by load, the input voltage feed-forward is used. In the voltage and current loop controllers, output saturation and integral component correction is implemented.This paper compares the simulation result of AC-DC rectifier circuit and Boost power factor correction is added, the simulated waveforms clearly show the improvement of power factor.In the hardware circuits, LEM sense and condition input inductor current, input voltage and the output voltage. These signals are fed back to the DSP via ADC channels; generate PWM duty ratio command for the PFC switch by program computed to make the waveforms of input current and voltage consistent.This paper realize the system simulation, indicate simulation wave, analyses the hardware design circuits and complete the part simulation, depict program flow charts of main program and interrupt program etc, point out the direction of further research.