Novel filter approach for ripple‑free input current boost converters based on variable inductors

다국어 초록 (Multilingual Abstract)

A coupled inductor filter (CIF) is a good candidate for reducing current ripple, and improving the power density of switching power. However, because the resonance frequency of its series branch is easily affected by non-ideal factors, such as the inductance production process, ambient temperature, device aging, among others, it is usually unable to optimize its effect in practice. To solve this problem, by considering the ripple-free input current boost converter as an example, this paper proposes a novel method that adds a variable inductor (VI) into the AC resonant branch of a CIF. The value of the VI is adjusted online to optimize the ripple cancellation effect by comparing the peak-to-peak current ripples in the main power inductor and the AC branch inductor. In the aforementioned scheme, the voltage-controlled current source (VCCS) in the closed loop control circuit is critical for achieving a rapid and stable regulation of the VI. Therefore, a 1/∛s compensator is adopted to provide a sufficient stability margin under various operating conditions. Finally, the input characteristics of a 500 W boost converter are measured and presented in this study. The obtained results demonstrate that the total inductor current ripple peak-to-peak values at each operating point are within 85 mA, which confirms the correctness of the theoretic analyses.