Three phase LCL filter and transformer with integrated magnetics for grid connected converters

Many grid connected power electronics systems need a dc/ac or ac/dc conversion stage. The LCL filter topology is commonly used to filter the harmonic content of the grid side current. Moreover, the use of a transformer provides galvanic isolation, and an extra freedom degree to adjust the output voltage level.The magnetic components often represent a significant part of the overall cost and size of the power converter, so an optimized design of the magnetic components is desirable. Magnetic integration techniques allow integrating several magnetic components in the same core, so they allow reducing the overall size and even increasing the energy efficiency in some cases. This work proposes a solution to integrate a three phase LCL filter and a transformer in a single core. The filter and the transformer can be designed by means of simple analytical equations. In addition, the windings of the proposed solution are split in sub-windings in order to allow designing the integrated components independently.