Unified Analytical Modeling of Multicell Interleaved Buck Converters with Parallel Switching Arms for Low-Ripple Electrochemical Energy Conversion Systems

Power electronic converters play an important role in proton exchange membrane (PEM) electrolyzers, where current ripple has been associated with electrode potential fluctuations, electrocatalyst degradation, and long-term system durability. This paper presents a unified analytical framework for multicell interleaved Buck DC-DC converters with parallel switching arms intended for low-ripple operation in electrochemical energy conversion systems. Existing steady-state analytical models are generally topology-specific and require new derivations for different converter configurations, limiting scalability and design flexibility. The proposed formulation considers a converter composed of k interleaved cells and M parallel switching arms per cell, resulting in a generalized converter architecture where the total number of switching devices is n = kM. Closed-form expressions are derived for the DC voltage gain, inductor current ripple, electrolyzer voltage ripple, and capacitor RMS current. The analysis shows that ripple cancellation and ripple-frequency multiplication are governed by the operating-region distribution and the total number of switching devices. In addition, normalized closed-form expressions are developed to establish scalable ripple-oriented design charts applicable to arbitrary converter configurations. By enabling the identification of operating conditions that minimize current ripple, the proposed methodology provides practical guidelines for the design of power converters supplying PEM electrolyzers and other catalyst-based electrochemical energy conversion systems. Consequently, the proposed model contributes to the development of power electronic interfaces that mitigate electrical stress on electrocatalysts, supporting improved durability and reliability of electrochemical energy conversion systems.