Trap filters in series with the well-known LCL filters have been proved to significantly increase the power density of inverters. This paper proposes a new method to integrate the trap and converter-side inductances in an LCL structure. The trap winding does not carry the fundamental current component, which further reduces the filter volume and loss. The proposed approach also enables the use of multiple traps coupled on one magnetic core. The equivalent circuits of the proposed integrated filter are derived and the effectiveness of this method is shown using Ansys Maxwell simulations and experimental results for a 500W/110V grid-connected inverter.
