Design of Interleaved Converters with Minimum Filtering Requirement

Paralleling power converters has been an attracting solution in many high power applications. Traditionally, LCL filters are adopted in each converter, which has been known as a challenge for control and reliability of the system. To simplify the control scheme and improve reliability, this study presents a system level investigation on the paralleled converters with L filter and interleaving technique. It is found that by interleaving sufficient number of converters, the total inductance of the L filter to meet the grid code can be smaller than that with LCL filter. The required number of interleaved converters to meet the grid code is determined analytically for both two-level and multilevel converters. Simulation results with 6 interleaved two-level converters and 6 interleaved three-level converters are obtained and presented in this paper. Experimental results also verify the analysis.