Fault Tolerant Operation of Interleaved Converters using a Bypass Switch Arrangement

The Secondary Loop Filter Building Block (SL-FBB) was proposed as a prospective modular Filter Building Block (FBB) candidate that is scalable and extendible to any number of converters without significant loss in harmonic attenuation. One major advantage of this filter structure is the fault tolerant aspect, also known as N-1 operation mode using an arrangement of bypass switches. Unlike conventional magnetically interconnected interleaved converters, the secondary loop based electrical interconnection allows for a seamless transition into N-1 mode with the reconfiguration of the bypass switch. Such a scheme does not exist for direct phase to phase coupling and is the major advantage of SL-FBB. Working principle and details are provided in this paper.