Filter design for N-port DC-DC converters

Modern power converters use input filters as power conditioners to guarantee the quality of equipment performance. Input filters have various topologies with primary objectives to reduce noise and improve system reliability. However, a poor implementation, in turn, can often hinder the dynamic performance and the stability of the converter. In this paper, the design of a single-section low-pass LC filter for N-port DC-DC converters is addressed. Mathematical expressions for the minimum sizing of the filter components are established using the voltage and current ripple. Frequency response analyses based on the converter state-space model are employed to study its performance. A linear feedback controller is then designed to stabilize the system. The LC filter design procedure is demonstrated for a 4-port DC-DC converter tied to the utility grid, a battery bank, a renewable energy source, and a load.