Zeta-Based Universal Converter with Zero-Current Switching

AC-link universal converters have emerged as promising topologies for efficient power conversion between various sources and loads. These converters offer enhanced reliability by replacing bulky electrolytic capacitors, which have a shorter lifetime compared to other power electronic components, with small and durable film capacitors. By doing so, the overall lifetime of the converter would be significantly extended. Additionally, AC-link converters achieve high-power density by utilizing compact high-frequency transformers when isolation is required, eliminating the need for large and heavy low-frequency transformers.This paper introduces a new soft-switching Zeta-based universal converter capable of stepping up and down the voltage in a wide range. Building upon the operating principles of the Zeta DC-DC converter, the proposed converter extends its applications to inverters, rectifiers, and AC-AC converters. In this converter, an inductor and a capacitor are responsible for transferring the power from input to output. Another small inductor is employed in series with the link capacitor to allow all switches to have zero-current switching, resulting in improved efficiency. In isolated configurations, the leakage inductance of the transformer can be used for this purpose. Compared to conventional Ćuk-based universal converters, this topology employs a capacitor with a lower voltage rating. The performance of the proposed structure is verified through simulation and experimental results in this paper.