A common magnetic integration method for single-phase LCL filters and LLCL filters

Compared to conventional L filters, LCL filters and LLCL filters have better high-frequency harmonic attenuation ability with less total inductance. However, one or two more magnetic cores are commonly demanded for grid-side and paralleled trap inductors. To further reduce the weight and volume of filter inductors, magnetic integration technique is an effective way. For conventional integrated LCL filters, the inevitable magnetic coupling would weaken the high-frequency harmonics attenuation ability, while for conventional integrated LLCL filters, the inverse coupling method would result in large weight and volume of inductor core. To tackle these concerns, a common magnetic integration method is explored in this paper for both LCL filters and LLCL filters. In the method, an additional winding in series with the filter capacitor branch is wound on the common flux path. Partial experimental results are finally provided to verify the effectiveness of the method.