Zeta-Based AC-Link Universal Converter

AC-link universal converters are relatively new topologies that can be used for power conversion from any type of source including, DC or AC, to any type of load. These converters enhance reliability by employing small film capacitors instead of bulky unreliable electrolytic ones. Furthermore, such converters have a high power density due to the possibility of using compact high-frequency transformers when isolation is needed. Universal converters extend the principles of the operation of DC-DC Buck-Boost and Cuk converters to DC-AC, AC-DC, and AC-AC power conversion systems. In this paper, a new Zeta-based universal converter is proposed, which is capable of stepping up and stepping down the voltage in a wide range. This converter uses an inductor and a capacitor for transferring power from the source to the load. The voltage rating of the capacitor and the current peak of the inductor used in the proposed converter are lower than those of Cuk-based and Buck-Boost-based universal converters, respectively. Moreover, the proposed topology is a single-stage power converter, which has a higher efficiency compared to conventional two-stage power converters. The principles of the operation of the proposed converter are presented in this paper, and its performance is verified through simulations and experiments.