Control For PFC Converters In Parallel Operation

Modulization is one of the directions in power electronics. Multi-module redundant parallel operation is a good solution to realize high reliability and large capacity of power system. The text studied emphatically the control technology and current sharing of the PFC modules. The operation principle of Boost PFC converter was analyzed; and the emulation model of Boost PFC module under the average current control was set up. A novel method to sample synthetically the input current and output current was put forward in the text. This can realize the current sampling for the control of PFC and current sharing at the same time. The emulation model of the parallel system was built too. Based on average current control, the control scheme and realization circuit of the parallel system was studied and designed.Finally, designed and finished the prototypes of the 300W Boost PFC module based on UC3854 and formed the parallel system. The characteristic experiment of stand-alone and paralleling system was carried on. The experimental result shows the control scheme of the paralleling of PFC module work reliable with good performance and is easy to realize in practice.