Design of Planar Magnetic Integrated LCL-EMI Hybrid Filter for the Grid-Connected Inverter

Numerous harmonics and electromagnetic interference (EMI) noise are prevalent in inverter system, potentially compromising output power quality. Harmonic and EMI filters serve as crucial components for mitigating harmonic distortion and EMI noise in grid-connected inverter. Nonetheless, these filters significantly increase the overall weight and volume of the inverter system, so there is a need to reduce their size and weight. This article uses planar magnetic integration technology to integrate the inductors of the LCL filter, the inductors of the passive EMI filter and the sampling coil of the active EMI filter into a single magnetic core unit through reasonable design of the PCB windings. In addition, capacitance integration is facilitated by the insertion of dielectric material between planar coil layers. This innovative approach effectively reduces the size and weight of the filter, consequently elevating the power density of the inverter system. The planar magnetic integrated LCL-EMI hybrid filter is analyzed using a single-phase Gallium-Nitride (GaN) inverter simulation and experimental platform, demonstrating that the design scheme reduces the size and weight of the filter while ensuring harmonic and EMI suppression. The feasibility of the planar magnetic integration scheme is thereby verified.