Analysis of Current in Pulsating DC Link Converter with Zero Voltage Transition

An exhaustive analysis of the evolution of current in the input power stage of insulated multistage DC/AC power converter based on the Pulsating DC link principle, characterized by Zero Voltage Transition (ZVT) of the output stage, is provided in this work. This topology is featured by an input power stage which provides on the second stage a pulsed voltage characterized by zero phases (pulsating DC link) which are used to achieve the ZVT conditions for the commutations of this stage. The specific and innovative topology of this converter influences the evolution of the main electrical characteristics and requires more attention on the design. The parameters that affects the behavior of the current in this particular topology, especially in the crucial working phases, are identified and their influence are analyzed to define the constraints of this system. A complete study of the current has been accomplished by LTSPICE simulator for different combination of leakage parameters of the architecture and switching frequency of the two power stages. The obtained results are presented and discussed to provide the limits of the design of the main components that compose this particular power converter. For the experimental validation of the results of the simulation, a 3.5kW prototype of the power converter was assembled and tested at different load conditions.