Design and simulation of a π-filter for medium and low-frequency conducted emission control

This research investigates the design and simulation of a π-filter intended for the suppression of conducted electromagnetic interference (EMI) in single-phase power electronic systems. The research addresses the complex and critical problem of achieving adequate attenuation at 160 kHz in accordance with MIL-STD-461 CE102 standards, using a standardized 100-ohm source/load impedance model. Traditional multi-stage filters, although effective in some scenarios, often fail to meet the strict attenuation requirements under worst-case operating conditions, particularly in challenging environments such as naval and CIP test scenarios where performance and reliability are paramount. The proposed solution is a single-stage π-filter with optimized passive components, derived from theoretical matrix modeling and analytical calculations. Simulations and measurements confirm that the filter meets the target insertion loss while remaining compact and low in component count. A key finding is that high attenuation strongly depends on higher K values, which dominate the system’s frequency response. This observed behavior is further explained through comprehensive logarithmic magnitude analysis and detailed Pareto evaluation, revealing that values of K greater than 6 are critical and necessary for achieving optimal filtering performance. In contrast to conventional filter designs, the presented π-filter structure demonstrates robust and consistent performance even under the most demanding and unfavorable EMI conditions. The proposed single-stage π-filter is particularly well-suited for aerospace and naval applications, where reliable EMI control is essential, and strict space constraints make compactness and efficiency critically important