Bandwidth-based analysis and controller design of power factor corrector for universal applications

The purpose of this paper is to analyze and design the controllers of power factor corrector for universal applications. And present its implementation using field programmable gate array. For the controller design, the bandwidth of voltage loop as the input voltage changes for PFC with and without input voltage feedforward will be analyzed. It will be shown that for the PFC without input voltage feedforward, the bandwidth of voltage loop varies as the input voltage changes. And the bandwidth of voltage loop for low line input is significantly reduced as it is designed based upon the high line input model. In contrast, the bandwidth of voltage loop of PFC for high line input is increased as it is designed based upon the low line input model. For the PFC with feedforward input voltage, the bandwidth of voltage loop retains constant for both low line and high line inputs and therefore no additional gains are required for universal input applications. This analysis provides a guideline for the design of PFC for universal input applications. Moreover, to fully take the advantages of digital control, an FPGA is used for the realization of digital-controlled PFC for universal input applications. Experimental results derived from an FPGA-based digital-controlled universal PFC are presented to fully support the presented PFC.