Benchmark of dc-link LC filters based on passive inductor and two-terminal active inductor

LC filters are widely used in power electronic systems for extracting the specific frequency band component, or absorbing harmonics. In the low-frequency harmonic filtering applications, bulky inductors and capacitors are implemented for low cutoff frequency, which contribute to high percent of volume, weight, cost, and failure rate. Recently, to exceed the limitations of the bulky inductors, a two-terminal active inductor concept has been proposed, which is implemented by power switches and energy storage elements. It has the same impedance characteristic at the frequencies of interest and has potential to replacing the bulky inductors in the LC filters. In order to explore the benefits of the new concept, this paper compares the performance of DC-link LC filters with a two-terminal active inductor and a passive inductor for a three-phase diode bridge rectifier. Benchmarking in terms of inductive energy storage, volume, and weight are compared. The electro-thermal and reliability performance of the filtering capacitors in the two filters are also investigated. Experimental results are provided to verify the accuracy of the theoretical analyses.