Fixed-Frequency Modulator for PFC with Power Semiconductor Filter to Mitigate Oscillation in the Input Current

Abstract

A fixed-frequency modulator for buck-boost-type power factor corrector (PFC) with power semiconductor filter (PSF) to mitigate input current oscillation caused by the grid inductance and the input capacitor of the entire power converter is presented. The idea is based on comparing the voltage across the PSF with a reference voltage, which consists of a voltage offset, a compensation ramp, and a sinusoid waveform voltage, to dictate the state of the switch. A 100W, 90-264Vac / 200Vdc PFC prototype to drive a plurality of LED lights has been built and evaluated. Experiment results show that the switching frequency is fixed at 200kHz and input current oscillation can be mitigated.