Review of Techniques for Resonant Converters with Wide Voltage Gain Range Applications

With the penetrations of renewable energies and electrified transportations, there is an increasing demand for power converters with wide voltage gain range operation capabilities due to the nature of the renewable energy sources, energy storage elements, and loads. As one of the most popular isolated DC/DC converter types, this article reviews the existing important techniques for resonant type converters with wide voltage gain range operation capabilities. The existing techniques can be classified into two groups according to whether modifications are required or not on the conventional resonant converters: 1) design and control strategy optimizations: this group includes accurate analysis methods and hybrid control strategies, and no modifications on the circuit topology are required; 2) topology improvement: based on where the modifications are made, it has three different subgroups, that is, primary inverter, resonant tank, and secondary rectifier. The general operation principles for each group are discussed and some representative literatures are selected for detailed discussions. Characteristics for each group are summarized, including advantages and disadvantages. Moreover, an application-oriented discussions and recommendations are made. Guidelines for technique selections can be obtained from the analysis and discussions that presented in this article.